Apex Mega Deck

What is an acyanotic shunt? -List 4 examples.

-An acyanotic shunt is also called a left-to-right shunt. Blood in the left side of the heart recirculates through the lungs Examples -VSD (most common) -ASD -PDA -Coarctation of the aorta

What is context sensitive half-time?

-Half-times DO NOT consider time. -The context sensitive half-time solves this problem. It is the time required for the plasma concentration to decline by 50% after discontinuing the drug

What is the treatment for acute intermittent porphyria?

-Liberal hydration -glucose supplementation (reduces ALA synthase activity) -Heme arginate (reduces ALA synthase activity) -Prevention of hypothermia

What is the risk associated with IV phytonadione?

-Life-threatening anaphylaxis, IV administration is best avoided. However, if given by this route, the rate should not exceed 1 mg/min

What conditions reduce albumin concentration?

-Liver disease -Renal disease -Old age -Malnutrition -Pregnancy

How does lung elasticity change in the elderly?

-Lung elasticity decreases. This collapses the small airways and causes the lung to become overfilled with gas Consequences -Increased Vd -Decreased alveolar surface area -V/Q mismatch -Increased A-a gradient -Decreased PaO2

Characteristics of A delta fibers

-Medium myelination -Diameter 2-5 -CV +++ ** Responsible for fast pain, temperature and touch

Characteristics of A gamma fibers

-Medium myelination -Diameter 3-6 -CV +++ **Responsible for skeletal muscle tone

List 6 drugs that are selective for Beta 1 receptor

-Metoprolol, atenolol, betaxolol, esmolol, acebutolol, bisoprolol

Examples of intermediate Hepatic ER

-Midazolam -Vec -Alfentanil -Methohexital

What is the vaporizer splitting ratio?

-Modern variable bypass vaporizers split FGF into two parts 1. FGF enters the vaporizing chamber and becomes 100% saturated with volatile agent 2. FGF bypasses the vaporizing chamber and does not pick up any agent -Before leaving the vaporizer, these two fractions mix and this determines the final anesthetic concentration exiting the vaporizer

A patient is undergoing CEA with EEG monitoring. What does this monitor tell you, and what conditions can lead to false conclusions?

-Monitors cortical electrical function -Risk of cerebral hypoperfusion with loss of amplitude, decreased beta-wave activity, and/or appearance of slow wave activity - High incidence of false negatives Increased frequency = mild hypercarbia, early hypoxia, seizures, ketamine, N2O, light anesthesia Decreased frequency = extreme hypercarbia, hypoxia, cerebral ischemia, hypothermia, anesthetic OD, opioids

Discuss hyperglycemic hyperosmolar state.

-More common with Type II DM -Usually caused by insulin resistance or inadequate production -Enough insulin is produced to prevent ketosis but not hyperglycemia -Hyperglycemia (> 600 mg/dL) significantly increases serum osmolarity -Compared to DKA - HHS is associated with a greater elevation in glucose and osmolarity -Glycosuria leads to dehydration and hypovolemia -Mild metabolic acidosis may occur -Treatment = volume replacement, insulin, correct electrolytes

How do opioids contribute to urinary retention?

-Mu and delta receptor stimulation -Detrusor relaxation and urinary sphincter contraction → urinary retention

How do opioids produce nausea and vomiting?

-Mu stimulation -Chemoreceptor trigger zone stimulation, possible interaction with the vestibular apparatus

How does rhabdomyolysis affect renal function?

-Myoglobin from rhabdo does effects renal function in two ways 1. Myoglobin precipitates in the proximal tubule (given acidic urine). This results in tubular obstruction and acute tubular necrosis 2. Myoglobin scavenges nitric oxide causing renal artery vasoconstriction

-For each agent, what percentage is attributed to hepatic metabolism?

-N2O = 0.004 -Des = 0.02 -Iso = 0.2 -Sevo = 2-5% *Rule of 2's 0.02, 0.2, 2 also in alphabetical order (for VA)

How does N2O affect hemodynamics?

-N2O activates the SNS. This increases MAP as a function of increased SVR. CVP/RAP may increase -N2O is also a myocardial depressant, but the increased SNS stimulation outweighs the physiologic consequences of this -Myocardial depression is more likely when N2O is used with an opioid

What is the relationship between N2O and anesthesia equipment?

-N2O can increase the volume and pressure in an ETT cuff, LMA cuff, or balloon-tipped PAC -Best way to check cuff pressure = manometer

Why does N2O accumulate in closed air spaces?

-N2O is 34x more soluble than nitrogen, this means it will enter a space 34 times faster than nitrogen can exit -N2O B:G = 0.46 -Nitrogen B:G = 0.014

List 2 drug classes and 7 drugs that are metabolized by pseudocholinesterase.

-NMB and Ester LA -NMB- succinylcholine and mivacurium -Ester LA- chloroprocaine, tetracaine, procaine, benzocaine, cocaine

MOA for ketamine?

-NMDA receptor antagonist (antagonizes glutamate) -secondary receptor targets- opioid, MAO, 5-HT, NE, muscarinic, NA+ channels -Ketamine dissociates the thalamus (sensory) from the limbic system (awareness)

Discuss the nitric oxide pathway of vasodilation

-Nitric oxide is a smooth muscle relaxant that induces vasodilation 1. Nitric oxide synthase catalyzes the conversation of L-arginine to nitric oxide 2. Nitric oxide diffuses from the endothelium to the smooth muscle 3. Nitric oxide activates guanylate cyclase 4. Guanylate cyclase converts guanosine triphosphate to cyclic guanosine monophosphate 5. Increased cGMP reduces intracellular calcium, leading to smooth muscle relaxation 6. Phosphodiesterase deactivates cGMP to guanosine monophosphate (turns off NO mechanism)

Characteristics of C Fibers

-No myelination -Diameter 0.3-1.3 -CV + **Sympathetic = Postganglionic ANS fibers **Dorsal root = slow pain, temperature, touch

Characteristics of B fibers

-No myelination -Diameter 3 -CV ++ **Preganglionic ANS fibers

What is noncompetitive antagonism? Give an example

-Noncompetitive antagonism is not reversible. The drug binds to a receptor and its effect cannot be overcome by increasing the concentration of the agonist. -The effect of a noncompetitive agonist can only be reversed by producing new receptors -Ex: aspirin and phenoxybenzamine

Discuss the anatomy of the renal cortex

-Outer part of kidney It contains the most parts of the nephron- glomerulus, Bowman's capsule, proximal tubules, distal tubules

Why are patients with CKD often anemic? What is the treatment for this?

Decreased EPO production = normochromic, normocytic anemia. Excess PTH replaces bone marrow with fibrotic tissue Treatment- epogen or darbepoetin + iron supplementation

How do acidosis and alkalosis affect CBF?

-Respiratory acidoses increase CBF -Respiratory alkalosis decreases CBF -Metabolic disorders do not directly affect CBF, but can lead to respiratory derangements that can

Why does succinylcholine have a black box warning?

-Sch has a black box warning that details the risk of cardiac arrest and sudden death secondary to hyperkalemia in children with undiagnosed skeletal muscle myopathy -This is caused by a MH-like syndrome characterized by rhabdomyolysis → NOT MH!

What are the CNS effects of midazolam?

-Sedation dose: Minimal effects -Induction dose: Decreased CMRO2 and CBF -Cannot produce isoelectric EEG -Anterograde amnesia (not retrograde) -Anticonvulsant -Anxiolysis -Skeletal muscle relaxation -No analgesia

What are the theoretical complications of sevoflurane metabolism?

-Sevo is not metabolized to TFA, but its transformation does result in the liberation of inorganic fluoride ions -Theoretical concerns of high output renal failure d/t fluoride ions S/Sx= polyuria, hypernatremia, hyperosmolarity, increased plasma creatinine, inability to concentrate urine

Name the 3 key plasma proteins. Does each bind acidic drugs, basic drugs, or both?

Albumin- primarily binds to acidic drugs Alpha-1-acid-glycoprotein- binds to basic drugs Beta-globulin- binds to basic drugs

In the context of cerebral aneurysm, how's transmural pressure calculated?

An increased transmural pressure predisposes the aneurysm to rupture. As the vessel burts, blood flows into the subarachnoid space

What are the effects of lidocaine at 1-5mcg/mL?

Analgesia

What are the changes in pulmonary mechanics due to obstructive lung disease?

Decreased FVC, FEV1, FEV1/FVC ratio and FEF 25-75% (problem is getting air out) Increased RV, FRC, and TLC d/t gas trapping

Rank the nerve fiber types according to their sensitivity to local anesthetics in vivo (most to least).

B fibers > C fibers > small diameter A fibers (gamma and delta) > Large diameter A fibers (alpha and beta)

Cardiac effects of alkalosis

Decreased P50 Decreased coronary blood flow Increased risk of dysrhythmias

Causes of increased ETCO2 due to changes in alveolar ventilation or equipment malfunction

Decreased VA- hypoventilation, CNS depression, residual NMB, COPD, high spinal, NM disease, metabolic alkalosis, Rx SE Equipment- rebreathing, CO2 exhaustion, Unidirectional valve malfunction, leak in breathing circuit, increased apparatus Vd

A patient has a type C TEF. Where should the tip of the ETT be positioned?

Below the fistula, but above the carina If too high, gas is delivered to the stomach If too low, endobronchial intubation is likely

Describe the recurrent laryngeal nerve innervation of the airway

Below the vocal cords to the trachea

What are the 3 building blocks of the LA molecule? How does each one affect the PK/PD profile of the molecule?

Benzene ring- Lipophilic- permits diffusion through lipid bilayers Intermediate chain-determines class, ester or amide, metabolism. Also allergic potential Tertiary amine- hydrophilic, accepts proton, makes molecule a weak base

Which class of NMB provide the most predictable DOA in patients with CKD?

Benzylisoquinolines Cisatracurium and atracurium

What are the 2 classes of NDNMB?

Benzylisoquinolinium compounds- atracurium, cisatracurium, mivacurium Aminosteroid compounds- roc, vec, pancuronium

What are the best anesthetic techniques for the patient with acute pericardial tamponade undergoing pericardiocentesis?

Best anesthesia- Local Safe RX- ketamine, N2O, benzos, opioids Avoid VA, propofol, thiopental, high dose opioids, neuraxial anesthesia

When is the best time to use an Eschmann introducer?

Best used when a grade 3 view is obtained during DL (grade 2 is next best time)

What is the MOA for class 2 anti-dysrhythmics?

Beta blockers Slows phase 4 depolarization in SA node Ex: esmolol, metoprolol, atenolol, propranolol

Where is the deep peroneal nerve blocked?

Between the tendons of the anterior tibial and extensor digitorum longus muscles Deep peroneal is at 00:00

How does superior laryngeal nerve injury affect the integrity of the airway?

Bilateral- Hoarseness, no respiratory distress Unilateral- Nothing, no respiratory distress

How does the arm position affect the NIBP reading? -How about when an arterial line is used?

Blood in the circulation behaves like a column of fluid and follows the rules of hydrostatic pressure BP cuff is above heart = BP falsely decreased BP cuff below heart = BP falsely increased When an aline is used, what matters is the level of the transducer

What is the dose of liquid emulsion for treatment of LAST?

Bolus 20% 1.5ml/kg (lean body mass) over 1 minute Infusion 0.25ml/kg/min If symptoms are slow to resolve, can bolus up to 2x more, and increase gtt to 0.5ml/kg/min. Continue gtt for 10min after achieving hemodynamic stability. Max recommended dose is 10ml/kg in the first 30 min

Describe the autonomic changes that occur in the elderly

Decreased adrenergic receptor density Decreased response to catecholamines Increased circulating catecholamines as partial compensation. Reduced ability to increase HR during hypotension due to decreased baroreceptor function. Impaired thermoregulation increases the risk of hypothermia.

What blood type is the universal donor for FFP? What about universal acceptor?

Donor = AB+ Acceptor = O-

What blood type is the universal donor for RBC? What is the universal acceptor?

Donor = O- Acceptor = AB+

What factors tend to reduce CO in the patient with obstructive hypertrophic cardiomyopathy?

Decrease systolic volume Decrease preload Increase heart rate Increase contractility Decrease aorta pressure Basically....not keeping them slow full tight

Causes of decreased ETCO2 that occur d/t changes in CO2 production

Decreased BMR Increased depth of anesthesia Hypothermia Decreased pulm blood flow Decreased CO Hypotension PE VQ mismatch Medication SE

CNS effects of alkalosis

Decreased CBF Decreased ICP

A patient is receiving PCV. What conditions can *decrease* the tidal volume delivered to the patient?

Decreased compliance - pneumoperitoneum - t-berg Increased resistance - bronchospasm - kinked ETT

A patient is receiving pressure controlled ventilation. What conditions can alter the tidal volume delivered to the patient?

Decreased compliance- pneumoperitoneum, Tburg Increased resistance- bronchospasm, kinked ETT

What factors decrease myocardial oxygen supply?

Decreased coronary flow- tachycardia, decreased aortic pressure, decreased vessel diameter (spasm or hypocapnia), increased EDP Decreased CaO2- hypoxemia, anemia Decreased Oxygen extraction-left shift of Hgb dissociation curve, decreased capillary density

How does CKD affect acid-base balance?

Decreased excretion of non-volatile acid contributes to a gap metabolic acidosis The patient will develop a compensatory respiratory alkalosis (hyperventilation) Acidosis shifts the oxyhemoglobin dissociation curve to the right. This partially compensates for the anemia

What is the etiology of hepatic encephalopathy? What is the treatment?

Decreased hepatic clearance = increased ammonia = cerebral edema = increased ICP Increased ammonia is treated with lactulose, ABX and reduced protein intake.

What conditions impair the reliability of the pulse ox?

Decreased perfusion- vasoconstriction, hypothermia, Raynaud's Dysfunctional Hgb- CarboxyHgb, MetHgb (not Hgb S or F) Altered optical characteristics- methylene blue, ICG, indigo carmine Non-pulsatile flow-LVAD, CPB Motion artifact- shivering/movement Cautery, venous pulsation

How do changes in plasma protein binding affect plasma drug concentration?

Decreased plasma protein binding = increased plasma concentration -Increased plasma protein binding = decreased plasma concentration

What *cardiac pathophysiology* is associated with a *cyanotic shunt*?

Decreased pulm BF: - hypoxemia - LV volume overload - LV dysfxn

Steps of RAAS

Decreased renal perfusion, SNS activation via B1, and tubuloglomerular feedback cause renin release from the juxtaglomerular cells. The renin converts angiotensinogen to angiotensin 1 Angiotensin 1 is converted to angiotensin 2 in the lungs via ACE Angiotensin 2 causes vasoconstriction in peripheral vessels and efferent arteriole. Aldosterone release from adrenal gland ADH release from posterior pituitary NA reabsorption Thirst mechanism activation

What *cardiac pathophysiology* is associated with an *Acyanotic shunt*?

Decreased systemic BF - low CO - HoTN Increased pulm BF - pulm HTN - RVH

Factors that cause a left shift in the oxyhemoglobin dissociation curve

Decreased temp, decreased 2-3 DPG, Decreased CO2, Decreased H+, increased pH Hgb Met, HgbCO, HgbF

Describe the sensory innervation to the lower extremity

Deep Peroneal is the thong Sural is lateral foot Tibial is heel Saphenous is medial leg Posterior femoral cutaneous n is hamstrings

Why are alcoholics susceptible to Wernicke-Korsakoff syndrome?

Deficiency in vitamin B1 (thiamine) WKS is characterized by a loss of neurons in the cerebellum d/t thiamine deficiency

Define pulmonary HTN, and discuss the goals of anesthetic management

Defined as mean PAP > 25 mmHg D/t COPD, left-sided heart disease, connective tissue disorders Goal is to optimize PVR

Management of the patient with DIC

Definitive = treat underlying cause. Otherwise supportive Hypovolemia- IVF Coagulopathy- replace consumed blood components with FFP, PLT, and cryo Severe microvascular thrombosis-IV heparin or LMWH

How does hypothyroidism affect gastric emptying

Delayed gastric emptying → increased risk of aspiration

What EKG findings are consistent with WPW syndrome?

Delta wave caused by ventricular preexcitation Short PR (<0.12 seconds) Wide QRS complex Possible T wave inversion

List 3 surgical procedures that warrant antibiotic prophylaxis against infective endocarditis.

Dental procedures involving gingival manipulation and/or damage to mucosa lining, respiratory procedures that perforate the mucosal lining with incision or biopsy, biopsy of infective lesions on the skin or muscle

How do you determine who should receive perioperative steroid supplementation?

Depends on how much exogenous steroid the patient is receiving for how long

Describe the Haldane effect

Describes CO2 carriage- says that increased O2 causes the RBC to release the CO2. Occurs in the lungs

Describe the Bohr effect

Describes O2 carriage- Increased Co2 and decreased pH will cause the RBC to release O2

What are 2 consequences of *desiccated soda lime*?

Desiccated soda lime + sevo = *compound A* - - - renal dysfxn Desiccated soda lime + des = *carbon monoxide* - - -carboxyhgbemia

What factors affect agent delivery to and removal from the alveoli?

Determinants of delivery- setting on vaporizer, time constant of delivery system, anatomic dead space, alveolar ventilation, FRC Determinants of uptake-Solubility (B:G coefficient), CO, PP gradient between alveolar gas and mixed venous blood

Describe the pathophysiology of Alzheimer's disease

Development of diffuse beta amyloid rich plaques and neurofibrillary tangles in the brain Consequences of plaque formation include: dysfunctional synaptic transmission. This is most noticeable in nicotinic Ach neurons, and apoptosis

What is the A-a gradient, and what factors affect it?

Difference between alveolar oxygen and arterial oxygen -Helps dx cause of hypoxemia by quantifying the amount of venous admixture Normal is 5-15 mmHg Increased by high FiO2, aging, vasodilators, right-to-left shunting, and diffusion limitation

Discuss the differential blockade of spinal anesthesia

Different types of nerves have different sensitivities to LA blockade Autonomic fibers are blocked first Sensory fibers blocked second Motor neurons blocked last Why is this important? Autonomic blockade is 2-6 dermatomes higher than sensory block Sensory block is 2 dermatomes higher than motor block

Explain diffusion hypoxia

Diffusion hypoxia is a risk during emergence -N2O moves from the body towards the lungs → dilutes alveolar O2 and CO2= decreased respiratory drive and hypoxia -Can be prevented by administering 100% O2 for 3-5 minutes after the N20 has been turned off

What is irradiation, why is it used, and who does it benefit?

Disrupts WBC DNA in the donor erythrocytes. DILLS DiGeorge syndrome Immunocompromised patients Leukemia Lymphphoma Stem cell transplanted patients,

How do GA and neuraxial anesthesia affect hepatic blood flow?

GA/neuraxial anesthesia reduce liver blood flow as a function of decreased MAP

What is the MOA for midazolam?

GABA-A agonist = increased frequency of channel opening = neuronal hyperpolarization *Most GABA-A agonists increase channel open time, but benzos increase channel opening frequency**

What is the MOA for thiopental?

GABA-A agonist- depresses the RAS in the brainstem -Low/normal dose increases the affinity of GABA for its binding site -High dose- directly stimulates the GABA receptor

What is the most important site of halogenated anesthetic action in the brain?

GABA-A receptor -increases Cl- influx and hyperpolarizes neurons = impaired neurotransmission -VA increase the duration that the Cl- channel remains open

What conditions allow extrajunctional receptors to populate the myocyte?

GBS MMH GBS Burns Severe sepsis/Infection Muscular denervation Muscular dystrophy Hemiplegia / prolonged paralysis

How does the GFR change in the elderly?

GFR decreases 1ml/min/year after age 40 GFR is 125 ml/min in the adult male Consequences include: risk of fluid overload and impaired drug elimination.

What are the *anesthetic considerations* for a patient undergoing a FBA with a rigid bronch?a

- inhalation induction w/ sevo to keep SV is BEST - avoid PPV (can push object down airway) - TIVA is best for maintenance - coughing/bucking can push FBA distally = not good!

The breathing bag of a *piston vent* ___________ during inspiration and _________during expiration

inflates deflates

What is calcitriol and what does it do?

ingested vitamin D or UV light➡️Calciferol➡️ Converted to vitamin D3 in the liver ➡️ converted to calcitriol in the kidney Calcitriol has 3 functions, it stimulates: 1. The intestine to absorb Ca+2 from food 2. The bone to store Ca+2 3. The kidney to reabsorb Ca+2 and phosphate

Describe the pathophysiology of *Ehrlers-Danlos syndrome*

inhereted d/o of procollagen and collagen ABP Arterial aneurysm risk Bleeding tendency (esp. into joints) PTX = common complication

How does *DMD* affect pulmonary fxn?

kyphoscoliosis (restrictive dz) - - dec. pulmonary reserve - - increased secretions + risk of pneumonia respiratory muscle weakness

How is AO subluxation diagnosed?

lateral x-ray of cervical spine distance btwn anterior arch of atlas (C1)

What location of an SpO2 sensor best correlates with retinal vessels?

preductal (RUE)

How does *myasthenia gravis* affect a pregnant woman?

pregnancy worsens MG s/sx

What wrong move can allow the PISS to be bypassed?

presence of more than one washer in between the hanger yoke assembly and stem of the tank

What is the purpose of the pin index safety system (PISS)?

prevent inadvertent misconnections of *gas cylinders* misconnections are *unlikely* but not impossible

What is the purpose of the diameter index safety system (DISS)?

prevents inadvertent misconnection of *gas hoses*

How does the *proportioning device* work?

prevents you from setting a hypoxic mixture w/ flow control valves by limiting N20 flow to 3x O2 flow for an N20 max of 75%

What is CATCH 22?

-Also called DiGeorge syndrome or 22q11.2 deletion syndrome -Cardiac defects -Abnormal face -Thymic hypoplasia -Cleft palate -Hypocalcemia -22q11.2 gene deletion

What is alpha-1 antitrypsin deficiency?

-Alveolar elastase is a naturally occurring enzyme that breaks down pulmonary connective tissue, this enzyme is kept in check by alpha-1 antitrypsin (produced in the liver) -When there's a deficiency of alpha-1 antitrypsin, alveolar elastase is free to wreak havoc on pulmonary connective tissue, resulting in panlobular emphysema

Which antibiotics are nephrotoxic?

-Aminoglycosides (gentamicin, tobramycin) -Amphotericin B -Vancomycin -Sulfonamides -Tetracyclines -Cephalosporins

In the *ELS* patient, which muscles are more affected - proximal or distal?

proximal muscles most affected

What conditions increase insulin release?

-Glucose is the primary stimulator of insulin release from the pancreatic beta cells

What is the prayer sign?

-Glycosylation of the joints → stiff joint syndrome with reduced ROM of AO joint → increased risk of difficult intubation

What are examples of CYP450 enzyme inhibitors?

-Grapefruit juice -cimetidine -Omeprazole -Isoniazid -SSRIs -Erythromycin -Ketoconazole

A machine passes the negative pressure test if the bulb attached to the CGO remains deflated for _________ seconds

10

What is the dose for FFP transfusion in the neonate?

10-20 ml/kg

Pt size, cuff inflation in mL, and largest ETT that fits for LMA 2?

10-20kg 10ml air in cuff Largest ETT 4.5

At what pH does the CO2 aborbent change to purple? What does it mean?

10.3 Soda lime is exhausted and will not neutralize CO2

At what Cobb Angle is a patient at *higher risk for post-op pulmonary complications*?

100

What is the maximum dose in mg/kg and max total dose in mg for mepivacaine?

7mg/kg Max total 400mg

What is the maximum dose in mg/kg and max total dose in mg for lidocaine with epi?

7mg/kg Max total 500mg

What is the pKa of Bupivacaine, Levo-bupivacaine, Ropivacaine?

8.1

What is the pKa of tetracaine?

8.5 Tetra means 4. but tetracaine means 8.5

What is the pKa of chloroprocaine?

8.7

What is the pKa of procaine?

8.9

What are the percentages of Epi and NE released from the adrenal medulla?

80% Epi 20% NE

What is the EBV in term neonates?

80-90 ml/kg

What is the EBV for an infant?

80ml/kg

What is the maximum dose in mg/kg and max total dose in mg for prilocaine?

8mg/kg If < 70 kg, max total is 500mg If >70 kg, max total is 600 mg

What is the EBV in preterm neonates?

90-100 ml/kg

Pt size, cuff inflation in mL, and largest ETT that fits for LMA 1

< 5 kg 4mL cuff inflation Largest ETT 3.5

What are the indications for PLT transfusion?

<50,000 - invasive procedures, neuraxial blockade, most surgery <100,000 eye and neurosurgery Qualitative PLT defect

What is high dose epi? What are the effects?

>0.15mcg/kg/min - alpha effects prevail, BP increases. Supraventricular tachyarrhythmias are common, so high dose epi is limited

If a patient requires > ______mg/kg of dantrolene, reconsider the diagnosis of MH

>20mg/kg

What are the 3 waves and 2 descents on the CVP waveform? What does each one signify?

A

How does a "tet spell" present? -What situations increases the risk of "tet spells?"

A "tet spell" presents as hypoxemia and cyanosis Classic- child squats during activity. This maneuver kinks the arteries in the groin, which increases SVR, which reduces R-L shunt and improves oxygenation Stress increases myocardial contractility and may cause spasm of the infra-valvular region of the RVOT. Tet spells occur during stressful experiences- exercise, crying, defacation, IV placement in the awake child, or during induction.

Which type of viral hepatitis has the highest incidence?

A = 50% B = 35% C = 15% D= co-infection with type B

List 6 drugs that are metabolized by non-specific plasma esterases.

A E RACE Atracurium (plus Hofmann) Etomidate (plus hepatic) Remifentanil Aspirin Clevidipine Esmolol

Why is a LV vent used during CPB?

A LV vent removes blood from the LV. This blood usually comes from the Thebesian veins and bronchial circulation (anatomic shunt)

What is Ludwig's angina?

A bacterial infection characterized by a rapidly progressing cellulitis in the floor of the mouth. -Most significant concern is posterior displacement of the tongue resulting in complete supraglottic airway obstruction

What is the plica mediana dorsalis, and what is its significance?

A band of connective tissue courses between the ligamentum flavum and the dura mater. Creates a barrier that could impact spread of medications within the epidural space. The plica mediana dorsalis has been considered the culprit for difficult epidural catheter insertion as well as unilateral epidural blocks

Complete the sentence: A base donates _____

A base donates OH-

What conditions decrease pulmonary compliance? How does this affect the peak pressure and plateau pressure?

A decreased pulmonary compliance is usually due to a reduction in static compliance - PIP and PP increase Ex: endobronchial intubation, pulmonary edema, pleural effusion, tension pneumo, atelectasis, chest wall trauma, abdominal insufflation, ascites, Tburg position, inadequate muscle relaxation

What types of nerve fibers transmit pain?

A delta fibers transmit "fast pain" that is sharp and well localized C fibers transmit "slow pain" that is dull and poorly localized

What are the 5 determinants of CBF?

CMRO2 CPP Venous pressure PaCO2 PaO2

What is the normal value for CMRO2? What factors cause it to increase? To decrease?

CMRO2 describes how much O2 the brain consumes per minute. Reference value is 3-3.8 ml/O2/100g/min Decreased by hypothermia, VA, propofol, etomidate, barbiturates Increased by hyperthermia, seizures, ketamine, N2O

How do halogenated anesthetics affect cerebral metabolic rate?

CMRO2 is a function of electrical activity (60%) and cellular homeostasis (40%) -VA reduce CMRO2, but only to the extent that they reduce electrical activity. Once the brain is isoelectric, VA cannot reduce CMRO2 any further -Isoelectric EEG occurs at 1.5-2 MAC

List 4 most common infectious complications of RBC transfusion from most to least common

CMV Hep B Hep C HIV

What is the most common infectious complication of RBC transfusion? How can this risk be reduced?

CMV Leukoreduction greatly reduces this risk, so immunocompromised patients should receive leukoreduced blood

How does Thyroid Hormone affect body systems?

CNN'S BIND HIT GILS Chronotropy, Inotropy, & Lusitropy ⬆️ Number and sensitivity of cardiac beta receptors ⬆️ Number of cardiac muscarinic receptors ⬇️ SVR ⬇️ BMR ⬆️ = ⬆️ CO2 = ⬆️vT & RR Induction slower w/ HYPER faster w/ HYPO No effect on MAC Diarrhea Heat loss d/t vasodilation from ⬆️ CO2 Inc neuronal sensitivity = tremors Thyroid needed for growth and development Gluconeogenesis increase Insulin release and glucose uptake increase Lipolysis Skeletal muscle weakness from protein catabolism

What are the CNS and cardiopulmonary effects of lidocaine at 5-10mcg/ml?

CNS = tinnitus, numbness of lips/tongue, skeletal muscle twitching, restlessness, vertigo, blurry vision CV = hypotension, myocardial depression

What is the CO in the newborn? How does this affect pharmacokinetics?

CO is 200ml/kg/min Means drugs are delivered to and removed from the body at a faster rate than in the adult

Describe the anesthetic management of constrictive pericarditis

CO is dependent on HR = avoid bradycardia -Preserve HR/contractility (ketamine, pancuronium, VA with caution, opioids/benzos/etomidate are ok) -Maintain Afterload Aggressive PPV can decrease venous return and CO

A lower PO2 means higher _____ is carried

CO2

What is the 2nd most common site of leaks in the breathing circuit?

CO2 cannister

How does hyperventilation affect CBF? What is the ideal PaCO2 to achieve this effect?

CO2 dilates the cerebral vessels = decreased cerebral vascular resistance = increased CBF = increased ICP Hyperventilation (PaCO2 30-35 mmHg) constricts the cerebral vessles = increased cerebral vascular resistance = decreased CBF = decreased ICP Lowering PaCO2 < 30 mmHg increases the risk of cerebral ischemia d/t vasoconstriction and shifting the oxyHgb dissociation curve to the left

Discuss the anesthetic considerations for maternal cocaine abuse

COCAINE CV risks include tachycardia, dysrhythmias, and myocardial ischemia OB risks include SAPP: Spontaneous abortion, APGAR scores low Premature labor & Placental abruption. Chronic use decreases MAC Acute intoxication increases MAC Inc resistance to ephedrine No BB...Can cause HF is SVR is high. Use vasodilators rather Evaluate platelets b4 neuraxial b/c cocaine causes thrombocytopenia

What disease process produces an obstructive pulmonary flow volume loop?

COPD, asthma

What is the MOA for COX inhibitors? Which agents provide irreversible COX inhibition?

COX inhibitors prevent PLT aggregation by blocking cyclooxygenase 1 (COX-1). This stops the conversion of arachidonic acid to prostaglandins, and ultimately thromboxane A2 ASA is irreversible- lasts the life of the PLT NSAIDs are reversible- duration is shorter than life of the PLT

What is the formula for CPP? What is normal?

CPP = MAP - ICP (or CVP) The cerebral vasculature autoregulates its resistance (vessel diameter) to provide a constant cerebral perfusion pressure of 50-150mmHg. Autoregulation is 50-150 CPP. NOT MAP

List 7 causes of secondary HTN

CRAHHPP Coarctation of the aorta Renal artery stenosis Atherosclerosis Hyperadrenocorticism (Cushing's syndrome) Hyperaldosteronism (Conn's syndrome) Pheochromocytoma Pregnancy-induced HTN

How does *DMD* affect cardiac fxn?

CRAMPRS JD Cardiomyopathy and CHF Reduced contractility Amplitude of R wave lead 1 increased & deep Q waves in the limb leads Mitral regurg Papillary muscle dysfunction Resting tachycardia S3/S4 gallop JD JVD Displacement of point of maximal impulse

What EKG changes might you see w/ *DMD*?

CRAMPRS JD Cardiomyopathy and CHF Reduced contractility Amplitude of R wave lead 1 increased & deep Q waves in the limb leads Mitral regurg Papillary muscle dysfunction Resting tachycardia S3/S4 gallop JD JVD Displacement of point of maximal impulse

What are *cardiac complications* of *RA*?

CRAP V Coronary artery arteritis Restrictive pericarditis, AR, Pericardial effusion/tamponade Valvular fibrosis,

Describe the production, circulation, and absorption of CSF

CSF production = ependymal cells of the choroid plexus at a rate of 30ml/hr Circulation- Love My 3 Silly 4 Lorn Magpies Reabsorption- venous circulation via the arachnoid villa in the superior sagittal sinus

What is the normal volume and specific gravity of CSF?

CSF volume 150 mL Specific gravity 1.002-1.009

Describe omphalocele

CULT OP Covered Umbilicus, midline Less urgent and less common gastro but requires CV workup Trisomy 21, Cardiac defects and Beckwith-widemann syndrome a/w Organs involved = bowel and sometimes liver Prosthetic slip closure

What are the CV and respiratory effects of propofol?

CV = decreased BP/SVR/Venous tone (decreases preload)/decreased myocardial contractility Respiratory = Shifts CO2 response curve down and to the right (Less sensitive to CO2) = respiratory depression and/or apnea, inhibits hypoxic ventilatory drive

What are the effects of lidocaine at >25mcg/mL?

CV collapse

What are the CV and respiratory effects of thiopental?

CV- Hypotension d/t venodilation/decreased preload. Causes histamine release = increases hypotension, but baroreceptor reflex intact = reflex tachycardia Respiratory- Respiratory depression, shifts CO2 response curve to the right, histamine release can cause bronchoconstriction- caution with asthma

What are the CV and respiratory effects of etomidate?

CV- minimal change in HR/SV/CO, but small reduction in SVR = small drop in BP. Does not block SNS response to DL, need opioid or esmolol Respiratory- mild respiratory depression

What are the CV/respiratory effects of midazolam?

CV- sedation dose = minimal effects IV Induction dose = decreased BP/SVR Resp- sedation dose- minimal effect Induction= respiratory depression *Opioids potentiate the respiratory depressant effects, even at sedation doses. Pts with COPD are more sensitive to respiratory depression effects*

What is the MOA for class 4 anti-dysrhythmics?

Ca channel blockers Decrease conduction velocity through the AV node Ex: Verapamil, diltiazem

Equation for oxygen carrying capacity and normal values (CaO2)

CaO2 = (1.34 x SaO2 x Hgb) + (PaO2 x 0.003) Normal 20 ml O2/dl

Equation for oxygen delivery (DO2) and normal value

CaO2 x CO x 10 Normal is 1000mL O2/min

What is the definitive test for susceptibility to *MH*?

Caffeine Halothane Contracture test (only 80% specificity - risk of false negative result)

Treatment for hypermagnesemia

Calcium chloride

List the treatment options for hyperkalemia

Calcium- stabilizes cardiac membrane Insulin + D50 Hyperventilation HCO3 Albuterol Potassium wasting diuretics Dialysis

How can the lumen of the bronchial blocker be used during OLV?

Can be used to insufflate oxygen to non-ventilated lung or suction air from non-ventilated lung to improve exposure. Can NOT be used to ventilate or suction blood/pus/secretions from non-ventilated lung

What is Eisenmenger's syndrome?

Can occur when a patient with a L-R shunt develops pulmonary HTN. This reverses the flow through the shunt, which causes a R-L shunt, hypoxemia, and cyanosis

How can the risk of succinylcholine induced myalgia be reduced?

Can only be minimized, not entirely eliminated by pre-treatment with NDNMB Other methods-NSAIDs, lidocaine, higher dose succs **Opioids do not reduce incidence of myalgia

Regarding hepatic clearance, what is capacity-limited elimination?

Capacity limited elimination- ER < 0.3 -For a drug with a low hepatic extraction ratio (<0.3), clearance is dependent on the ability of the liver to extract drug from the blood. Changes in hepatic enzyme activity or protein binding have a profound impact on the clearance of these drugs. -Changes in the liver's intrinsic ability to remove drug from the blood is influenced by the amount of enzyme present -Enzyme induction = increased clearance -Enzyme inhibition = decreased clearance

Pathophysiology of carbon monoxide poisoning

Carbon monoxide reduces the oxygen carrying capacity of blood. It binds to the oxygen binding site on Hgb with an affinity 200x that of O2. Oxidative phosphorylation is impaired and metabolic acidosis results. -CO is measured with a CO-oximeter Patients are cherry red SNS stimulation may be confused as light anesthesia or pain

Discuss the pathophysiology of carcinoid syndrome

Carcinoid syndrome is associated with secretion of vasoactive substances from enterochromaffin cells. It is usually associated with tumors of the GI tract, but it can also arise from locations outside of the GI tract (lungs) -These tumors tend to release histamine, serotonin, kinins, and kallikrein

Describe the pathophysiology of pericardial tamponade

Cardiac tamponade occurs when fluid accumulates inside the pericardium. What separates it from a pericardial effusion is that the excess fluid exerts an external pressure on the heart limiting its ability to fill/act like a pump. CVP rises in tandem with pericardial pressure. As ventricular ocmpliance deteriorates, L and R sided diastolic pressure begin to equalize. TEE is the best method of dx, and the best tx is pericardiocentesis or pericardostomy

What is the cause of cauda equina syndrome? What factors increase the risk?

Cause - neurotoxicity due to exposure to high concentrations of LA Factors that increase risk- 5% lidocaine and spinal micro catheters

What is the cause of TNS? What factors increase the risk?

Cause- patient positioning, stretching of the sciatic nerve, myofascial strain, and muscle spasm. Factors that increase risk- lidocaine, lithotomy position, ambulatory surgery, knee arthroscopy

What is the Modified NY Association Functional Classification of Heart Failure?

Class 1-Asymptomatic Class 2- Symptomatic with moderate activity Class 3- Symptomatic with mild activity Class 4- symptomatic at rest

Which *antiarrhythmics* are appropriate for the treatment of MH?

Class I: - procainamide 15mg/kg IV - lidocaine 2mg/kg IV

How does the heart compensate for volume overload?

Eccentric hypertropy- Sarcomeres added in series

What area of the spinal cord do MEPs monitor?

anterior cord motor function *do NOT use NMBs*

How does *myasthenia gravis* affect a fetus?

anti-AchR IgG antibodies cross placenta and cause weakness in 15 - 20% of neonates can persist up to 2-4 weeks may require airway mgmt

*Flow tube structure & fxn* What is the *annular space*? Where is it the narrowest? What is it's purpose?

area btwn indicator float and side wall of flow tube narrowest at base, widest at top "variable orifice" architecture provides a constant gas pressure throughout a wide range of flow rates

Which ventilation mode will deliver the same tidal volume whether the machine or the patient initiates a breath?

assist control

Describe the pathophysiology of *systemic lupus erythematosus(SLE)

autoimmune dz proliferationof antinuclear antibodies affects nearly every organ system most sequelae result from antibody-induced vasculitis and tissue destruction

Describe the pathophysiology of *RA*

autoimmune dz targets synovial joints cytokines play central role in patho

Describe the temperature compensation for a *variable bypass vaporizer*

automatic

Which type of fetal decelerations cause concern?

-Late and variable decelerations require urgent assessment of fetal status

Which patient population should not receive a defasciculation dose of a NDNMB?

Patients with pre-existing skeletal muscle weakness (Ex: MG)

How do extrajunctional receptors affect the clinical use of non-depolarizing neuromuscular blockers?

Patients with upregulation of extrajunctional receptors are resistant to NDNMB Dose may need to be increased

Discuss the process of pain perception

Perception describes the processing of afferent pain signals in the cerebral cortex and the limbic system -"How we feel about pain"

List the 5 phases of the ventricular action potential and describe the ionic movement during each phase.

Phase 0- depolarization- Na influx Phase 1-Initial repolarization- K+ efflux and Cl influx Phase 2- Plateau- Calcium influx Phase 3- Repolarization- K+ efflux Phase 4- Na/K pump restores RMP

What is the architecture of the SNS efferent pathway?

Preganglionic- Short, myelinated B fiber, Releases ach Postganglionic- Long unmyelinated C fiber, releases NE (Ach is released at sweat glands, piloerector muscles and some vessels)

What are absolute contraindications to ESWL?

Pregnancy Risk of bleeding- bleeding disorder or anticoagulation

What are the 2 types of nicotinic receptors present at the NMJ? What is the function of each?

Prejunctional Nn receptor- Present on the presynaptic nerve, regulates Ach release Postjunctional Nm receptor-present at the motor end plate on the muscle cell, responds to Ach by depolarizing muscle

MAC in children- does this rule apply to all the VA?

Premature (delivered before 37wks) = MAC < neonate Neonate (<4wks) = MAC < infant Infant 1-6 months = MAC > adults Infant 2-3 months = MAC peaks Sevo is different 0 days to 6 months = MAC is > (3.2%) 6 mo to 12 years = MAC is lower, but still > adults (2.5%)

What is the #1 cause of perinatal morbidity and mortality? Define it. What newborns are at even higher risk for M&M with this condition? What maternal condition puts the neonate at risk for this? What do complications of this include?

Prematurity: < 259 days from the last menstrual cycle or < 37 weeks Risk is even ⬆️ for newborns < 1500g. Higher risk prematurity if multiple gestations and PROM. Complications include: RIN HHH RDS Intraventricular hemorrhage NEC Hypoglycemia Hypocalcemia Hyperbilirubinemia

What is the most common cause of prerenal injury? What is the treatment?

Prerenal injury = hypoperfusion Treatment = reduce risk by maintaining MAP >65 mmHg and providing appropriate hydration IVF, hemodynamic support, PRBCs Avoid NSAIDs An improvement in UOP following IVF bolus confirms the diagnosis of prerenal azotemia

How can you use renal function tests to differentiate between prerenal oliguria and ATN?

Prerenal oliguria Fe(Na) < 1 Urine Na < 20 mEq/L Urine osmolality >500 Bun:Cr >20.1 Sediment- Normal, possible hyaline casts ATN Fe(Na) >3 Urine Na >20 Urine osmolality <400 Bun:Cr 10-20.1 Sediment- tubular epithelial cells, granular casts

Clinical presentation and treatment of Epiglottitis?

Presentation- high fever, Tripod positioning. 4 D's: drooling, dysphonia, dyspnea, dysphagia OSAP Oxygen Spontaneous ventilation induction - CPAP 10-15cmH20 prevents airway collapse An ENT surgeon must be present Post-op ICU Urgent airway mgmt - Tracheal intubaiton - Tracheostomy

Discuss the clinical presentation and treatment of Croup?

Presentation- mild fever, inspiratory stridor, barking cough OH FRIC O2 Humidification Fluids Racemic epinephrine Intubation rarely required Corticosteroids

What is the best way to minimize the risk of postintubation laryngeal edema?

Prevention Maintain an air leak < 25 cm H2O Use a manometer to intermittently measure cuff pressure

Anesthetic management of the patient with AH

Prevention is best! GA or spinal anesthesia Treat HTN by removing stimulus, deepening GA, rapid acting vasodilator- SNP Tx bradycardia with atropine/glyco May present in post-op period as effects of anesthesia wear off = closer post-op monitoring is required

Name the 2 LA most likely to produce a leftward shift of the oxyhemoglobin dissociation curve. Why does this happen?

Prilocaine and benzocaine The O2 binding site on the heme portion of the Hgb molecule contains an iron molecule in it's ferrous form (Fe2+) Oxidation of the iron molecule to its ferric form (Fe3+) creates MetHgb MetHgb impairs O2 binding and unbinding from the Hgb molecule, shifting the curve to the left, creating physiologic anemia

What's the difference between primary and secondary HTN?

Primary HTN- AKA essential HTN- occurs in 95%, has no identifiable cause Secondary is caused by some other pathology- about 5% of cases

What is the site of action for spinal anesthesia?

Primary site of action is on the myelinated preganglionic fibers of the spinal nerve roots LA also inhibit neural transmission in the superficial layers of the spinal cord.

A patient with a respiratory infection presents for a tonsillectomy. Which signs and symptoms favor postponing the procedure?

Proceed with caution: RAN COCA Runny nose w/o other s/s Active No fever Clear nasal discharge Older child Clear lungs Appears happy Good reasons to cancel: PPFL Purulent nasal discharge Persistent cough Poor appetite Fever Lethargic Wheezing/rales that doesn't clear with cough Child < 1yo, or previous preemie

What are the common characteristics of the opioid partial agonists?

Produce analgesia with a reduced risk of respiratory depression Ceiling effect = additional analgesia is not possible Reduce efficacy of previously administered opioids Can cause acute opioid withdrawal in the opioid dependent patient Can cause dysphoric reactions Low risk of dependence

How does pregnancy affect minute ventilation?

Progesterone is a respiratory stimulant, it increases minute ventilation by up to 50% -Vt increases by 40% -RR increases by 10%

Describe the pathophysiology of *myotonic dystrophy*. What does it result from?

Prolonged contracture after voluntary contraction. Contractions so severe they can interfere with ventilation and intubation Results from dysfunctional calcium sequestration by the SR

What is propofol infusion syndrome?

Propofol contains long chain triglycerides and increased LCT load impairs oxidative phosphorylation and fatty acid metabolism. This starves cells of O2, particularly cardiac and skeletal muscles. -High mortality rate

What is another name for the *hypoxia prevention safety device*?

Proportioning device

Contrast neostigmine reversal in adults and children.

When compared to adults, antagonism with neostigmine is faster in infants and children

4 contraindications to IABP?

Severe aortic insufficiency Descending aortic disease Severe PVD Sepsis

What is the Hamburger shift?

When the RBC releases HCO3 into the plasma, Cl is transported into the RBC to maintain electroneutrality

What does it mean when a CO2 absorbent becomes *desiccated*?

granules are 13 - 20% water by weight "desiccated" means devoid of water

How should succinylcholine dosing be adjusted in the patient with *MG*?

potency is decreased INCREASE dose to 1.5 - 2.0mg/kg

How should non-depolarizer dosing be adjusted in the patient with *MG*?

potency is increased REDUCE dose by 1/2 to 2/3

What conditions impair atlanto-occipital joint mobility?

DRATS KD Degenerative joint disease RA Ankylosing spondylitis Trauma Surgical fixation Klippel-Feil Down syndrome

Discuss the path blood follows after it enters the renal artery.

Filtration occurs at the glomerular capillary bed Reabsorption and secretion occur at the peritubular capillary bed.

What is the key function of the distal tubule?

Fine tunes the solute concentration (variable aldosterone and ADH)

What is the architecture of the PNS efferent pathway?

Preganglionic- Long, myelinated, B fiber, releases Ach Postganglionic- short, unmyelinated C fiber, releases Ach

Which syndromes are associated with difficult airway management?

"Big Tongue"= Beckwith & Trisomy "Please Get That Chin" = Pierre Robin, Goldenhar, Treacher collins & Cri du chat "Kids Try Gold" = Klippel fell, trisomy & Goldenhar

In the patient with *ToF*, the heart may mimic the appearance of what on an x-ray?

"boot-shaped"

Be able to calculate the GCS

(4) Eyes: (5) Verbal: distinguish between inappropriate vs incomprehensible vs none (3,2,1) (6) Motor: Flexion vs abnormal flexion vs extension (3,2,1)

What are the hemodynamic goals for diastolic HF?

(Kind of like concentric hypertrophy goals - Slow, Full Tight) -Increase preload -Keep afterload elevated to perfuse a thick myocardium, preserve CPP -Keep heart slow/normal to increase diastolic time and CPP

What are the hemodynamic goals for systolic HF?

(Kind of like eccentric goals - Full, Fast and Forward) Decrease to afterload to reduce myocardial workload, maintain CPP. -Augment contractility with inotropes -HR is usually high d/t increased SNS tone, if EF is low a higher HR is needed to preserve CO

What induction agents produce an active metabolite?

*Always think about active metabolites when a patient has kidney or liver dysfunction, or with prolonged administration** -Midazolam produces 1-hydroxymidazolam -Ketamine- Norketamine -Fospropofol produces propofol

What factors affect myocardial contractility?

*Chemicals affect Contractility - particularly Calcium

What are the complications of rigid bronchoscopy?

*Rigid bronchoscopy is the "gold standard" procedure to retrieve the foreign body Complications -Laryngospacm -Bradycardia during scope insertion -Post-intubation croup -Pneumothorax

What are the precursors of the endogenous opioids?

*The only one you really have to remember is endorphins. All others are their namesake + "pre" Pre-proopiomelanocortin - endorphins (mu receptor) Pre-enkephalin- enkephalins (delta receptor) Pre-dynorphin - dynorphins (kappa receptor)

The negative pressure relief valve opens at _________cmH20 to protect against negative end-expiratory pressure

- 8

Describe the pathophysiology of *Eaton-Lambert syndrome*

- IgG mediated destruction of *pre*-synaptic voltage-gated Ca+2 channel @ presynaptic nerve term - When AP depolarizes nerve term, Ca+2 entry into presynaptic neuron is limited, thereby reducing amnt of Ach released into synaptic cleft - Postsynaptic nicotinic receptor is normal in quantity and function

Describe the pathophysiology of *Guillain-Barre Syndrome (GBS)*.

- acute idiopathic polyneuritis - immunologic assault on myelin in peripheral nerves - AP cannot be conducted, so motor endplate never receives incoming signal

What are the *airway considerations* for a patient with *cleft lip and palate*?

- airway obstruction - difficult DL - difficult mask - aspiration risk *Dingman-Dott mouth retractor can reduce venous drainage and cause tongue engorgement, thus increasing the risk of post-extub airway obstruction*

Describe the pathophysiology of *myasthenia gravis (MG)*

- autoimmue dz - IgG antibodies destroy *post*-junctional Ach *receptors* at NMJ - Ach quantity is not decreased; there are not enough receptors to translate response - manifests as *skeletal muscle weakness*

What are the 7 ways to monitor for disconnection of the breathing circuit?

- precordial stethoscope - visual inspection of chest rise - capnography - respiratory volume monitors - low expired volume alarm - low peak pressure alarm - failure of bellows to rise (ascending) *O2 analyzer monitors conc% of O2 in circuit, does NOT alarm for disconnect*

Discuss the antipruritic and antiemetic effects of propofol.

-10mg IV can reduce itching d/t spinal opioids or cholestasis -Propofol 10-20mg IV can be used to treat PONV. An infusion of 10mcg/kg/min can also be used

What % of pts w/ TEF suffer from other congenital anomalies. What is the VACTERL association?

-25-50% of patients with TEF suffer from other congenital anomalies, collectively known as the VACTERL association -Vertebral defects -Imperforated anus -Cardiac anomalies -Tracheoesophageal fistula -Esophageal atresia -Renal dysplasia -Limb anomalies

Discuss the Monroe-Kellie hypothesis.

-3 Components: brain, blood, and CSF -If there is an increase or decrease in any of these components, the others must inversely adjust to maintain a baseline

Who is at highest risk for developing gallstones?

-3 F's → Female, fat, forty Incidence of gallstones increases with obesity, aging, rapid weight loss, pregnancy, and women > men

What are the constituents of EMLA cream?

-50/50 combination of 2.5% lidocaine and 2.5% prilocaine -Prilocaine can result in methemoglobinemia

How does PaO2 affect CBF?

-A PaO2 below 50 mmHg causes cerebral vasodilation and increases CBF. -A PaO2 above 60 mmHg has no affect on CBF

How do you interpret cardiac enzymes in the patient with a suspected ischemic event?

-A cell requires O2 to maintain the integrity of its cell membrane, and a cell deprived of O2 dies and releases its contents into systemic circulation -Infarcted myocardium releases 3 key biomarkers: creatinine kinase-MB, troponin I, and troponin T -Cardiac troponins are more sensitive than CK-MB for the dx of MI -These values must be evaluated in the context of time on the patient's EKG

What is a cyanotic shunt? List 5 examples

-A cyanotic shunt is also called a right-to-left shunt. Venous blood bypasses the lungs Examples (5 T's) -Tetralogy of Fallot -Transposition of the great arteries -Tricuspid valve abnormality (Ebstein's anomaly) -Truncus arteriosus -Total anomalous pulmonary venous connection

What is the extraction ratio?

-A measure of how much drug is delivered to a clearing organ vs how much is removed by that organ -ER of 1.0 means that 100% of the drug delivered to the clearing organ is removed -ER of 0.5 means that 50% of the drug delivered to the clearing organ is removed Formula- ER = arterial concentration-venous concentration/arterial concentration

What is a racemic mixture? List some commonly used examples

-A racemic mixture contains 2 enantiomers in equal amounts - About 1/3 of the drugs we give are enantiomers, and almost all are racemic mixtures. -Ex: bupivacaine, ketamine, isoflurane, desflurane

Name 2 tests of hepatocellular injury

-AST (10-40 units/L) -ALT (10-55 units/L) -Marked elevation of both suggests hepatitis -AST/ALT ratio of > 2 suggests cirrhosis or alcoholic liver disease

How is fospropofol converted to its active form?

-Alkaline phosphatase converts fospropofol to propofol -This explains the slower onset (5-13 mins) and longer duration (15-45 mins)

What plasma proteins are produced by the liver?

-All of the plasma proteins except for immunoglobulins -Albumin -Alpha-1 acid glycoprotein -Pseudocholinesterase

Name 2 antifibrinolytics and 4 fibrinolytics

-Antifibrinolytics stop the conversion of plasminogen to plasmin, they promote clot formation → Tranexamic acid, aminocaproic acid -Fibrinolytics facilitate the conversion of plasminogen to plasmin. They break down clots → tPA, urokinase, reteplase, alteplase

What are the unique effects of kappa stimulation?

-Antishivering -Diuresis -Dysphoria -Delirium -Hallucinations

How is the anesthetic delivery affected by altitude? When does this matter?

-As atmospheric pressure decreases at higher elevations, the vol% of a gas remains the same, however the partial pressure of the gas decreases. The risk is underdosing the patient (PP determines depth of anesthesia) -For sevo or iso at elevation, not an issue because the variable-bypass vaporizer compensates for changes in elevation -Des = underdosing, because the injector does not compensate for elevation

How does pregnancy affect gastric emptying?

-Before onset of labor = no change -After onset of labor = slowed

What is amaurosis fugax?

-Blindness in one eye -Sign of impending stroke. Emboli travel from the internal carotid artery to the ophthalmic artery, which impairs perfusion of the optic nerve and causes retinal dysfunction.

What are the respiratory effects of ketamine?

-Bronchodilation -Upper airway muscle tone and airway reflexes remain intact -Maintains respiratory drive, although a brief period of apnea may occur following induction -Does not shift the CO2 response curve -Increased PO and pulmonary secretions → increased risk of laryngospasm

Theophylline has a low hepatic extraction ratio. Which will have a greater effect on its metabolism: prolonged hypotension or CYP inhibition?

-CYP inhibition

What are the potential SE of flumazenil?

-Can produce signs of withdrawal in chronic benzo user = seizures

How do you manage the patient with thyroid storm?

-Cardiopulmonary support -Active cooling measures -PTU or methimazole -Beta-blockers -Acetaminophen for fever -Avoid aspirin -Management is the same in pregnant and non-pregnant patients

What is salvaged blood syndrome?

-Cell saver blood does not return platelets and coagulation factors to the patient -If a large volume of salvaged blood is returned to the patient → consider the possibility of dilutional coagulopathy

What is chirality?

-Chirality is a division of stereochemistry. It deals wth molecules that have a center of three-dimensional asymmetry. In biologic systems, this type of asymmetry generally stems from the tetrahedral bonding of carbon - carbon binds to 4 different atoms -A molecule with 1 chiral carbon will exist as 2 enantiomers, the more chiral carbons, the more enantiomers

How does HTN affect cerebral autoregulation?

-Chronic HTN shifts the curve to the right. This adaptation helps the patient's brain tolerate a higher range of blood pressures, however this comes at the expense of not being able to tolerate a lower blood pressure.

Describe the anatomy of the circle of willis

-Circle of Willis functions to provide redundancy of blood flow in the brain. If one side becomes occluded, the other side should be able to perfuse the affected areas.

How does circulation time change in the elderly?

-Circulation time increases, reduced CO prolongs the time of drug delivery -Slower IV induction, faster inhalation induction

What is clearance? What factors increase/decrease it?

-Clearance is the volume of plasma that is cleared of drug per unit time -Clearance is directly proportional to blood flow, to clearing organ, extraction ratio, and drug dose. -Clearance is inversely proportional to half-life and drug concentration in the central compartment

What are the indications for FFP transfusion?

-Coagulopaty → PT or PTT > 1.5x control -Coumadin reversal (acute need) -Antithrombin III deficiency -Massive transfusion -DIC -C1 esterase deficiency

What is the CHARGE association?

-Coloboma (a hole in one of the eye structures) -Heart defects -(A) -Choanal atresia -Retardation of growth and development -Genitourinary problems -Ear anomalies

What is competitive antagonism? Give an example

-Competitive antagonism is reversible -Increasing the concentration of the agonist can overcome competitive antagonism -Ex: Atropine, vecuronium, rocuronium

What is the minimum FGF requirement for sevo?

-Compound A is a halogenated vinylic ether. While its associated with renal tubular necrosis in rats, there is no supporting evidence that this complication occurs in humans. -Even so, the FDA recommends a minimum FGF of 1L/min for up to 2 MAC hours, and 2L//min after 2 MAC hours

What is the relationship between adrenocortical suppression and etomidate?

-Cortisol and aldosterone synthesis are dependent on the enzyme 11-beta-hydroxylase located in the adrenal medulla. -Etomidate is a known inhibitor of 11-beta-hydroxylase and 17-alpha-hydroxylase -A single dose of etomidate suppresses adrenocortical function for 5-8 hours -Etomidate should be avoided in patients reliant on the intrinsic stress response (sepsis, acute adrenal failure)

How do halogenated agents affect heart rate?

-Decrease SA node automaticity -Decreased conduction velocity through AV node, Purkinje system, and ventricular conduction pathways -Increase duration of myocardial depolarization by impairing the outward K+ current (prolongs action potential duration and QT interval) -Altered baroreceptor function

What are the CNS effects of etomidate?

-Decreased CMRO2 -Decreased CBF -Decreased ICP -Cerebral perfusion pressure remains stable -No analgesia

What are the CNS effects of thiopental?

-Decreased CMRO2 -Decreased CBF -Decreased ICP -Decreased EEG activity -No analgesia

What are the CNS effects of propofol?

-Decreased CMRO2 -Decreased CBF -Decreased ICP -Decreased IOP -No analgesia -Anticonvulsant properties

What factors stimulate glucagon release?

-Glucagon is secreted by pancreatic alpha cells. It's a catabolic hormone that promotes energy release from adipose and the liver.

Describe the components of the neuron and their functions

-Dendrites receive and processes signal -Soma integrates signal/cellular machinery -Axon sends signal -Presynaptic terminal releases neurotransmitters Axon Hillock Nodes of Ranvier Myelin

Describe the Frank-Starling relationship

-Describes the relationship between ventricular volume (preload) and ventricular output (cardiac output) -Increasing preload increases ventricular output, but only up to a point. To the right of the plateau additional volume over-stretches the ventricular sarcomeres, reducing cardiac output.

Discuss differential blockade using epidural bupivacaine as an example

-Differential blockade is the idea that some fiber types are blocked sooner (easier) than others -Epidural bupivacaine serves as an excellent example, because at lower concentrations, it provides excellent analgesia but spares motor function -As concentration is increased, it anesthetizes more resistant nerve types- those that control motor function and proprioception

What preservatives are used in brand and generic propofol? What patient populations are at risk?

-Diprivan (brand) contains EDTA- not a concern for any specific population -Generic propofol formulations contain different preservatives with unique problems -Metabisulfite = bronchospasm in asthmatic patients -Benzyl alcohol=avoid in infants

What is the MOA of propofol?

-Direct GABA-A agonist = increased chloride conducance = neuronal hyperpolarization

What is the dose, onset, duration, and clearance mechanism for etomidate?

-Dose = 0.2-0.4 mg/kg IV -Onset- 30-60 seconds -Duration- 5-15 minutes -Clearance- Hepatic P450 enzymes + plasma esterases

What is the dose, onset, DOA, and clearance mechanism for thiopental?

-Dose Adult 2.5-5mg/kg, Kids 5-6 mg/kg -Onset 30-60 seconds -DOA- 5-10 min -Clearance- Liver via CYP 450 enzymes *awakening is d/t redistribution

How is potency measured on the dose-response curve?

-Drug A is more potent than Drug B - Drug A- curve shifts left with increased affinity for receptor, higher potency, lower dose required -Drug B- curve shifts right with decreased affinity for the receptor, lower potency, higher dose required

What is efficacy, and how is it measured on the dose-response curve?

-Efficacy is a measure of the intrinsic ability of a drug to produce a clinical effect -The height of the plateau on the Y-axis represents efficacy

What is an enantiomer? What is the clinical relevance?

-Enantiomers are chiral molecules that are non-superimposable mirror images of one another. -Different enantiomers can produce different clinical effects. For example, the SE profile of one enantiomer of a drug can be different from another enantiomer of the same drug

What is the treatment for hemophilia A?

-Factor VIII concentrate prior to surgery -FFP and cryoprecipitate can also be used to replace factor VIII, however their use increases the risk of transfusion related disease -Antifibrinolytics (tranexamic acid or aminocaproic acid) can be used to minimize bleeding during dental procedures -A type and crossmatch is required for any surgical procedure

How does anterior spinal artery syndrome present?

-Flaccid paralysis of LE -Bowel and bladder dysfunction -Loss of Temperature and Pain sensation -Preserved Touch and Proprioception (Dorsal column FPP V) Remember...Anterior is Spinothalamic tract SPTIC T Sexual sensation, Pain Temperature Itch Crude touch Tickle

What is the reversal agent for benzodiazepines? How does it work?

-Flumazenil is a competitive antagonist of the GABA-A receptor -High affinity but short DOA-may require repeat dose -Initial dose 0.2 mg IV, titrated in 0.1mg increments Q1M

What conditions decrease FA/FI?

-For FA/FI to decrease, there must be lower wash-in or increased uptake -Decreased wash-in- Low FGF, low VA, High FRC, high time constant, high anatomic dead space -Increased uptake - high solubility, high CO, high Pa-Pv difference

What conditions increase FA/FI?

-For FA/FI to increase, there must be greater wash-in or reduced uptake -Increased wash in= high FGF, high VA, low FRC, low time constant, low anatomic dead space -Decreased uptake- low solubility, low CO, low Pa-Pv difference

Discuss the intrinsic vasodilating effects of local anesthetics. -Which local anesthetic has the opposite effect?

-For most of the drugs we administer, absorption into the bloodstream begins the process of delivering a drug to its site of action. LA are different, we administer them directly to their site of action. Absorption into the systemic circulation removes the LA from its site of action and contributes to termination of its effect. -Cocaine is unique- it always causes vasoconstriction, because it inhibits NE reuptake in sympathetic nerve endings in vascular smooth muscle

What are the differences between a full agonist, partial agonist, antagonist, and inverse agonist?

-Full agonist- binds to receptor and turns on a specific cellular response - Partial agonist- binds to a receptor, but it is only capable of partially turning on a cellular response. It is less efficacious than a full agonist - Antagonist- occupies the receptor and prevents an agonist from binding to it. It does not tell the cell to do anything -Inverse agonist- binds to the receptor and causes an opposite effect to that of a full agonist. It has negative efficacy

What are other uses for glucagon?

-Glucagon 1-5 mg IV increases myocardial contractility, heart rate, and AV conduction by increasing the intracellular concentration of cAMP. It does this independently of the ANS Useful in: -Beta-blocker overdose -CHF -Low cardiac output after MI or CPB -Improving MAP during anaphylaxis Also administered during ERCP to relax the biliary sphincter

How does head position affect ICP?

-Head elevation > 30 degrees facilities venous drainage away from the brain -Neck flexion or extension can compress the jugular veins, reduce venous outflow, increase CBV, and increase ICP -Head down positions increase CBV and ICP

Why do neonates receive vitamin K after birth?

-Healthy intestinal flora is required for the gut to synthesize vitamin K -Neonates don't have the intestinal flora that synthesizes vitamin K, so 0.5-1 mg IM after delivery is common

Characteristics of A beta nerve fibers

-Heavy myelination - Diameter 5-12 - CV ++++ **Responsible for touch and pressure

Characteristics of A alpha nerve fibers

-Heavy myelination - diameter 12-20 -+++++ CV *Responsible for motor function of skeletal muscle, and proprioception

Define therapeutic index

-Helps to determine the safety margin for a desired clinical effect Therapeutic index = LD50/ED50 -Drug with narrow TI = narrow margin of safety -Drug with wide TI = wide margin of safety

Discuss the pathophysiology of acute intermittent porphyria

-Heme is a key component of Hgb, myoglobin, and the CYP450 enzymes. Porphyria is d/t a defect in heme synthesis that promotes the accumulation of heme precursors (ALA induction)

How is hemophilia B different from hemophilia A?

-Hemophilia B is a factor 9 deficiency. -Labs and anesthetic management are similar to hemophilia A with 1 exception → Factor IX concentrate is used instead of factor VIII

How does protamine reverse heparin?

-Heparin is a large negatively charged particle -Protamine is a highly alkaline compound with a strong positive charge -The positive charge of protamine and the negative charge of heparin neutralize each other and stop heparin's anticoagulant activity

Anesthetic overpressure results in a more profound effect for agents with a (higher/lower) blood solubility?

-Higher blood solubility -the concentration effect says that an anesthetics' onset is directly proportional to the concentration delivered to the alveolus -When applied to VA, overpressure will have a more profound effect with agents of higher blood solubility. -Can offset effects of higher blood solubility by increasing inspired concentration on vaporizer. Helps reach FA/FI equilibration faster

What are mineralocorticoid effects?

-Hypertension (Na+ and water retention) -Hypokalemia (K+ wasting) -Metabolic alkalosis (K+ wasting)

Heart Block Poem

-If the R is far from the P then you have a first degree -Longer, longer, longer drop then you have a Wenkebach -if some Ps don't get through then you have a Mobitz II -If Ps and Qs don't agree then you have a third degree

What is the relationship between etomidate and seizure activity?

-If the patient does not have a hx of seizures, then etomidate does not increase the risk of seizures. -If the patient has a hx of seizures, then etomidate can increase epileptiform (seizure like) activity and possibly increase the risk of seizures. This property can make it useful for mapping seizure foci

What are the CNS effects of ketamine?

-Increased CMRO2 -Increased CBF -Increased ICP -Increased IOP -Increased EEG activity -Nystagmus -Emergence delirium

What conditions affect alpha-1-acid-glycoprotein concentrations?

-Increased concentrations with surgical stress, MI, chronic pain, RA, advanced age -Decreased concentration in neonates and pregnancy

What is the concentration effect?

-Increased rate of alveolar uptake as the concentration of a gas is increased -Function of 2 mechanisms: -Concentrating effect: When N2O is introduced into the lung, the volume of N2O going from the alveoli to the pulmonary blood is much higher than the amount of nitrogen moving in the opposite direction → Alveoli shrink and the reduction in alveolar volume causes a relative increase in FA -Augmented gas inflow: On the subsequent breath, the concentrating effect causes an increased inflow of tracheal gas containing anesthetic agent to replace the lost alveolar volume. This increases alveolar ventilation and augments FA

What are the CV effects of ketamine?

-Increases SNS tone. -Increases CO/HR/SVR/PVR *requires intact SNS- if catecholamine stores are depleted or with sympathectomy, will actually have myocardial depression**

What is the pumping effect?

-Increases vaporizer output -Anything that causes gas that has already left the vaporizer to re-enter the vaporizer chamber → PPV or O2 flush valve

How can propofol injection pain be minimized?

-Injecting into a larger vein -Lidocaine (before or mixed with propofol) -Administration of an opioid prior to propofol

What are the 4 classifications of receptors?

-Ion channel -G-protein coupled receptor -Enzyme linked receptor -Intracellular receptor

What is ionization? What 2 factors determine how much a molecule will ionize?

-Ionization describes the process where a molecule gains a positive or negative charge. -The amount of ionization is dependent on 2 things: pH of solution, and pKa of the drug

What is the relationship between isoflurane and coronary steal?

-Iso is the most potent coronary artery dilator -Underlying principal is that atherosclerotic vessels can't dilate but normal vessels can. This would preferentially divert blood away from the areas of higher resistance, starving those regions of O2

How can methergine be administered?

-It can be given 0.2 mg IM (not IV) -IV administration can cause significant vasoconstriction, hypertension, and cerebral hemorrhage

What is Kussmaul's sign?

-JVD and increased CVP- most pronounced during inspiration

How do LA affect neuronal depolarization?

-LA bind to alpha-subunit on the inside of the sodium channel when it's in either the active or inactive state -when a critical number of sodium channels are blocked, there aren't enough open channels for sodium to enter the cell in sufficient quantity -The cell can't depolarize and the AP can't be propagated. Whatever modality that nerve services (pain, mvmt, etc) is blocked

6 complications of HTN?

-LVH -IHD -CHF -Arterial aneurysm (aorta, cerebral circulation) -CVA -ESRD

Define pharmacokinetics, pharmacobiophysics, and pharmacodynamics. How do they relate to each other?

-Pharmacokinetics- "what the body does to the drug" Explains the relationship between dose given and plasma concentration over time. Influenced by absorption/distribution/metabolism and elimination -Pharmacobiophysics- considers the drug concentration in the plasma and the effect site (biophase) -Pharmacodynamics- what the drug does to the body- explains the relationship between the effect site concentration and the clinical effect

What is a function of a phase 1 reaction? What are 3 examples?

-Phase 1 reactions result in molecular changes that increase the polarity (water solubility) of a molecule to prepare it for a phase 2 reaction- it creates a location on the molecule that will allow the phase 2 reaction to take place. Most phase 1 biotransformations are carried out by the P450 system -3 key phase 1 reactions -Oxidation- adds an oxygen molecule Reduction- adds electrons to a compound Hydrolysis-adds water to a compound to split it apart (usually an ester)

Describe the 4 phases of the normal capnograph

-Phase I (A-B) → Exhalation of anatomic dead space -Phase II (B-C) → Exhalation of anatomic dead space + alveolar gas -Phase III (C-D) → Exhalation of alveolar gas -Phase IV (D-E) → Inspiration of fresh gas that does not contain CO2

List 5 ways the fetal circulation is different than the adult circulation.

-Placenta is the origin of respiration - Circulation is arranged in parallel -R-L shunting occurs across the foramen ovale and ductus arteriosus -PVR is high because the lungs are collapsed and filled with fluid. There is very little pulmonary blood flow. -SVR is low, the placenta provides a large, low resistance vascular bed.

What is placenta previa? How does it present?

-Placenta previa occurs when the placenta attaches to the lower uterine segment -It partially or completely covers the cervical os -Associated with painless vaginal bleeding -Potential for hemorrhage

Describe the process of fibrinolysis

-Plasminogen is a proenzyme that is synthesized in the liver. It is incorporated into the clot as it's being formed, but it lays dormant until it is activated -Plasmin is a proteolytic enzyme that degrades fibrin into fibrin degradation products

What is potency and how is it measured?

-Potency: The dose required to achieve a given clinical effect (x-axis of the dose-response curve) -The ED50 and ED90 are measures of potency. They represent the dose required to achieve a given effect in 50% and 90% of the population respectively.

What are contraindications to radioactive iodine?

-Pregnancy and breastfeeding mothers

What are the risk factors for ROP?

-Prematurity (biggest risk factor) -Low birth weight -Hyperoxia SIM B LVH Sepsis IVH Mechanical ventilation Blood transfusion Low birth weight Vitamin E deficiency Hyperoxia

Discuss ketamine and emergence delirium (presentation, treatment, risk factors)

-Presents as nightmares and hallucinations (risk for up to 24 hours) - Benzos are best way to prevent (midazolam > diazepam) -Risk factors- >15 years, female, ketamine dose >2mg/kg, or history of personality disorder

How do halogenated agents reduce blood pressure?

-Primary cause: Decreased intracellular Ca+2 in vascular smooth muscle → systemic vasodilation → decreased SVR and venous return -Secondary cause: Decreased intracellular Ca+2 in the myocyte → myocardial depression → decreased inotropy

What are the CNS effects of dexmedetomidine?

-Produces sedation that resembles natural sleep -Sedation is the result of decreased SNS tone and decreased arousal -Does not provide reliable amnesia -Decreased CBF -No change in CMRO2 -No change in ICP

What is the formulation of propofol? Is there a patient population where this is a problem?

-Profol is prepared as a 1% solution in an emulsion of egg lecithin, soybean oil, and glycerol -Theoretical concern to giving to patients with egg allergy

When must a propofol syringe be discarded? -How about an infusion?

-Propofol supports bacterial and fungal growth, therefore, strict attention to asepsis must be observed while withdrawing the drug from the vial. Additionally, the vial and rubber stopper must be cleansed with 70% isopropyl alcohol before removing the drug. - Syringe (drug out of vial) = discard w/in 6 hours -Infusion- must be discarded w/in 12 hours

Discuss the analgesic properties of ketamine

-Provides good analgesia & opioid-sparing effect -Relieves somatic pain > visceral pain -Blocks central sensitization and wind-up in the dorsal horn of the spinal cord -Prevents opioid induced hyperalgesia (after remifentanil infusion) -Good for burn patients and those with pre-existing chronic pain

What is retinopathy of prematurity?

-ROM causes abnormal vascular development in the retina. -The immature retinal blood vessels are at risk of vasoconstriction and hemorrhage → retinal detachment and blindness

What are the 4 defects associated with tetralogy of Fallot?

-RVOT obstruction - RVH due to high pressure load from RV obstruction - VSD d/t septal malalignment -Overriding aorta that receives blood from both ventricles *Ratio of PVR to SVR determines how much blood travels to the lungs and the systemic circulation

Which inhalation anesthetics are stable in soda lime? What byproducts can each agent produce in soda lime?

-Sevo- not stable in soda lime, can produce compound A -Des- not stable in soda lime, can produce CO with dessicated soda lime -Iso-Not stable in soda lime, can produce CO with dessicated soda lime

What is the treatment of vaso-occlusive crisis?

-Sickled cells → impaired tissue perfusion → ischemic injury -Most common manifestation of sickle cell disease -Treatment → analgesics and hydration -Hydroxyurea reduces the incidence and severity of vaso-occlusive crisis

Discuss the role of ionization with respect to local anesthetics.

-Since LA are weak bases with pKa values >7.4, we can predict that >50% of the LA will exist as the ionized, conjugate acid after injection -The non-ionized fraction diffuses into the nerve. Once inside the neuron, the law of mass action promotes re-equilibration of charged/uncharged species. The charged species binds to the alpha-subunit on the interior of the voltage-gated Na channel

What is solubility, and how do we measure it?

-Solubility: The tendency of a solute to dissolve into a solvent. The ability of the anesthetic agent to dissolve into blood and tissues. -The blood:gas partition coefficient describes the solubility of an inhalation anesthetic in the blood vs. in the alveolar gas when the partial pressures between the 2 compartments are equal

Define the 3 stages of labor

-Stage 1: Beginning of regular contractions to full cervical dilation (10 cm) -Stage 2: Full cervical dilation to delivery of the fetus -Stage 3: Delivery of the placenta

Describe the 4:2:1 rule of fluid management.

-Step 1: 0-10 kg → Begin with 4 mL/kg/hr -Step 2: 10-20 kg → Add 2 mL/kg/hr to the previous total -Step 3: > 20 kg → Add 1 mL/kg/hr to the previous total Shortcut-If the patient is > 20 kg → patient's weight in kg + 40

How do opioids affect ventilation?

-Stimulation of the mu and delta receptors produce the ventilatory effects -Decreased ventilatory response to CO2 -Decreased RR and compensatory increase in Vt - increased PaCO2 which increases ICP if ventilation is not maintained

What signs suggest dehydration in the neonate?

-Sunken anterior fontanel -Weight loss (a 10% reduction the first week is normal) -Irritability or lethargy -Dry mucus membranes -Absence of tears -Decreased skin turgor -Increased hematocrit in the absence of transfusion

What does the FA/FI curve tell us? -How does anesthetic solubility affect the FA/FI curve for each agent?

-The FA/FI curve allows us to predict the speed of induction -Low solubility = less uptake into the blood = increase rate of rise = faster FA/FI equilibration = faster onset -High solubility = more uptake into the blood = decrease rate of rise = slower FA/FI equilibration = slower onset

Which region of the heart is most susceptible to myocardial ischemia and why?

-The LV subendocardium is most susceptible to ischemia -THe LV subendocardium is best perfused during diastole. As aortic pressure increases, the LV tissue compresses its own blood smupply and reduces blood flow. The high compressive pressure in the LV subendocardium coupled with a decreased coronary artery blood flow during systole increases coronary vascular resistance and predisposes this region to ischemia.

Describe the function of the sodium-potassium pump

-The Na/K Pump maintains the cell's resting potential. It keeps the inside of the cell negative and the outside of the cell positive. -For every 3 Na+ ions it removes, it brings 2 K+ ions into the cell

Describe the pin index safety system

-The PISS prevents inadvertent misconnections of gas cylinders -The pin configuration on each hanger yoke assembly is different for each gas, making unintended connections of the wrong gas unlikely, but not impossible. -The presence of one washer between the anger yoke assembly and the stem of the tank may allow the PISS to be bypassed

Compare and contrast the effects of halogenated anesthetics and N2O on CBF?

-The brain matches its blood flow with its metabolic requirement -When metabolic demand increases, the blood vessels dilate (cerebrovascular resistance decreases) -When metabolic demand decreases, the blood vessels constrict (Resistance increases) -VA uncouple this relationship: CMRO2 decreases and CBF increases. Can increase ICP -N2O increases CMRO2 and CBF the same

When compared to nitrous oxide, desflurane has a lower blood-gas partition coefficient. Why does the FA/FI ratio for N2O rise faster than desflurane?

-The concentration effect explains this phenomenon -Despite a slightly higher blood/gas partition coefficient, the alveolar partial pressure of N2O rises faster than desflurane. This is because we can safely deliver a much higher inspiratory concentration, and this negates the small difference imposed by the slightly higher blood/gas partition coefficient

Discuss the context sensitive half-times of fentanyl, alfentanil, sufentanil, and remifentanil. -Which has the longest? -Which has the shortest? -Why?

-The context-sensitive half-time for a fentanyl infusion increases as a function of how long it was infused. A longer infusion had more time to fill up the peripheral compartments, therefore more fentanyl has to be eliminated and it will have a longer elimination half-time. -Remifentanil is the exception. even though it is highly lipophilic, It is quickly metabolized by plasma esterases and has a similar context-sensitive half-time regardless of how long it was infused

Give 1 example of how the oxygen pressure failure device (failsafe) might permit the delivery of a hypoxic mixture

-The failsafe device checks pressure- NOT FLOW! -If there is a pipeline crossover, then the pressure of the new gas will provide the pressure to defeat the failsafe device. The patient will be exposed to a hypoxic mixture

Midazolam contains an imidazole ring. -How does this affect solubility?

-The imidazole ring can assume the open or closed position depending on the environmental pH. -Acidic pH - ring opens = increased water solubility -Physiologic pH- ring closes = increased lipid solubility

What law can be used to describe ventricular afterload?

-The law of Laplace helps to better understand ventricular afterload Wall stress = (Intraventricular pressure x radius)/ ventricular thickness -Intraventricular pressure is the force that pushes the heart apart -Wall stress is the force that holds the heart together (counterbalances intraventricular pressure) Wall stress is reduced by decreased intraventricular pressure, decreased radius, and increased wall thickness

Discuss excitation-contraction coupling in the cardiac myocyte

-The myocardial cell membrane depolarizes -During the plateau of the ventricular action potential (phase 2), Ca2+ enters the cardiac myocycte through L-type Ca channels in the T tubules -Ca influx turns on the ryanodine-2 receptor, which releases Ca from the SR -Ca binds to troponin C -Ca unbinds from troponin C -Most of the Ca is returned to the SR via the SERCA2 pump -Once inside the SR, Ca binds to a storage protein called calsequestrin -The next time the myocyte depolarizes, the whole process repeats

Aside from IV, what other routes can dexmedetomidine be administered? -What is the dose?

-The nasal and buccal routes have a high degree of bioavailability. This makes it useful for preop sedation in children -3-4mcg/kg 1 hour prior to surgery

Discuss the use of magnesium for preeclampsia.

-The presence of seizures differentiates between preeclampsia and eclampsia Seizure prophylaxis with mag sulfate -Loading dose → 4 g over 10 minutes -Infusion → 1-2 g/hr Treatment for Mg. toxicity -10 mL of 10% calcium gluconate IV

What is angioedema

-The result of increased vascular permeability that can lead to swelling of the face, tongue, and airway.

What does the slope of the dose-response curve tell you?

-The slope tells us how many of the receptors must be occupied to elicit a clinical effect -Steeper slope = small increase in dose can have a profound clinical effect -Flatter slope- higher doses are required to increase the clinical effect

Define volume of distribution and recite the equation.

-The volume of distribution describes the relationship between a drug's plasma concentration following a specific dose. It is a theoretical measure of how a drug distributes throughout the body. Equation VD = amount of drug/desired plasma concentration

Describe the innervation of the adrenal medulla. How is it different than the typical SNS efferent architecture?

-There are no postganglionic fibers -The preganglionic fibers release Ach onto the chromaffin cells and the chromaffin cells release EPI and NE into systemic circulation

What is the relationship between CMRO2 and CBF?

-Things that increase the amount of O2 the brain uses tend to cause cerebral vasodilation → hyperthermia and ketamine -Things that decrease the amount of O2 the brain uses tend to cause cerebral vasoconstriction → hypothermia and propofol *Volatile anesthetics are the exception, they decouple to relationship between CMRO2 and CBF → reduce CMRO2 but cause cerebral vasodilation

Describe the treatment of aspiration

-Tilt head downward or to the side -Upper airway suction, don't worry as much about lower airway suction -Secure the airway -PEEP to reduce shunt -Bronchodilators to reduce wheezing -Lidocaine to reduce neutrophil response -Steroids probably don't help -Antibiotics are only indicated if the patient develops a fever or increased WBC count > 48 hours

What are examples of drugs that cause CYP450 enzyme induction?

-Tobacco smoke - barbiturates -ethanol -phenytoin -rifampin -Carbamazepine

How is each type of viral hepatitis transmitted?

-Type A = Oral/Anal -Type B = percutaneous or sexual contact -Type C = percutaneous -Type D = percutaneous

Discuss the relationship between FiO2 and ROP. When does the retina mature?

-Until retinal maturation is complete (44 weeks post-conception) FiO2 should be titrated to SpO2 of 85-93%

Which VA are metabolized to trifluoroacetic acid? What is a potential consequence of this?

-Up to 40% of halothane undergoes hepatic biotransformation, and a high concentration of TFA in the liver is the mechanism for halothane hepatitis -Although des and iso undergo a much smaller degree of hepatic biotransformation, there remains a very small possibility that TFA could precipitate an immune-mediated hepatic dysfunction, especially in a patient with previous TFA exposure

What does the Apgar score mean?

-Used to assess the newborn and guide resuscitation efforts -Parameters are evaluated at 1 and 5 minutes after delivery. The score at 1 minute correlates with acid-base status, the score at 5 minutes is predictive of neurologic outcome. -Normal → 8-10 -Moderate distress → 4-7 -Impending demise → 0-3

Discuss the use of 2-chloroprocaine for labor

-Useful for emergency C/S when epidural is already in place -Metabolized by pseudocholinesterase in the plasma - minimal placental transfer -Antagonizes opioid receptors (mu & kappa) and reduces the efficacy of epidural morphine -Risk of arachnoiditis when used for spinal

What conditions can reduce uterine blood flow?

-Uterine blood flow does not autoregulate → dependent on MAP, CO, and uterine vascular resistance -Decreased perfusion → maternal hypotension -Increased resistance → uterine contraction, hypertensive conditions

What are the treatment options for uterine atony?

-Uterine massage -Oxytocin -Ergot alkaloids -Intrauterine ballon

How do halogenated anesthetics contribute to hypercarbia?

-VA cause a dose-dependent depression of the central chemoreceptor and respiratory muscles. This contributes to hypercarbia -Alters respiratory pattern (decreased VT and compensatory increase in RR = decreased minute ventilation with increased Vd) -Impairing response to CO2 (shifts response curve down and right) -Impairing motor neuron output and muscle tone to upper airway and thoracic muscles

What is vapor pressure, and how is it affected by the ambient temperature?

-Vapor pressure is the pressure exerted by a vapor in equilibrium with its liquid or solid phase inside a closed container -VP is directly proportional to temperature (increase temp = increased VP)

What are the 3 types of Von Willebrand disease?

-Von Willebrand disease is the most common inherited disorder of platelet function, the platelet count is normal, but the platelets do not function properly. -Type I: Mild-moderate reduction in the amount of vWF produced -Type II: The vWF that is produced doesn't work well -Type III: Severe reduction in the amount of vWF produced

What are androgenic effects?

-Women become masculinized (hirsutism, hair thinning, acne, amenorrhea) -men become feminized (gynecomastia, impotence)

Describe the pathophysiology of hemophilia A

-X-linked chromosomal disorder (more common in males) that causes factor VIII deficiency -Severe disease (Factor VIII activity < 1%) is associated with spontaneous bleeding into the joints, muscles, and vital organs

Who is at the highest risk of myalgia following succinylcholine? Who is at lowest risk?

-Young adults undergoing ambulatory surgery (women > men) and those who do not routinely engage in strenuous activity -Children, elderly and pregnant patients have the lowest rate of occurrence

Which inhalation anesthetics are most greatly affected by a left-to-right shunt?

-a Left to right shunt will not have a meaningful effect on anesthetic uptake or induction time

Compare/contrast the alpha and beta distribution phases on the plasma concentration curve

-alpha distribution phase- describes the distribution from the plasma to the tissues -beta distribution phase begins as plasma concentration falls below tissue concentration. The concentration gradient reverses, which causes the drug to re-enter the plasma. The beta phase describes drug elimination from the plasma by the clearing organs.

List 6 nonselective BB

-carvedilol, labetolol, nadolol, pindolol, propranolol, timolol

How do hyper- and hypothyroidism affect MAC?

-do not directly affect MAC, however, changes in CO associated with these conditions may affect the anesthetic uptake and subsequent onset of action -profoundly hypothyroid patients have a reduced CO leading to decreased uptake into blood and faster rate of rise of FA/FI = higher risk for anesthetic OD

Why is dexmedetomidine attractive for procedural sedation?

-does not cause respiratory depression -no change in oxygenation -no change in pH -no change in slope of CO2 response curve

Examples of high hepatic ER

-fentanyl -sufentanil -morphine -meperidine -naloxone -ketamine -propofol -lidocaine/bupivacaine -Metoprolol/propranolol -nifedipine -diltiazem/verapamil

Examples of drugs with low hepatic ER

-roc -diazepam -lorazepam -methadone -thiopental -theophylline -phenytoin

List 5 factors that govern the uptake and plasma concentration of LA

-site of injection -tissue blood flow -physiochemical properties of LA -metabolism -addition of vasoconstrictor

Describe the CV effects of isoproterenol

-synthetic catecholamine that stimulates B1 and B2 receptors -increases HR, contractility and MVO2 -Decreases SVR -Causes severe dysrhythmias and tachycardia -vasodilates non-essential vascular beds in muscle and skin = not able to be used with sepsis

How and when do local anesthetics bind to the voltage-gated sodium channel?

-the guarded receptor hypothesis states that LA can only bind to Na channels in their active (open) and inactive (closed refractory) states. LA do not bind to sodium channels in their resting states LA are more likely to bind to axons that are conducting action potentials and are less likely to bind to those that are not. This is AKA use-dependent or phasic blockade

What is conduction velocity, and how is it affected by myelination and axon diameter?

-the measure of how fast an axon transmits the action potential -increased by myelination- action potential skips along the nodes of Ranvier (AKA saltatory conduction) and large fiber diameter

What is the MELD score, and what do the numbers mean?

...MELD with and C BIS Creatinine Bilirubin INR Sodium . Low risk = < 10 Intermediate = 10-15 High = >15

What is low-dose epi? What are the effects?

0.01-0.03mcg/kg/min -At low doses, nonselective beta effects predominate. B1 stimulation increases HR/contractility, while B2 mediates vasodilation in skeletal muscle. Net effect is increased CO with reduced SVR, possible for slight reduction in BP. Pulse pressure is wider

What is intermediate dose epi? What are the effects?

0.03-0.15mcg/kg/min -this dose range is characterized by mixed alpha and beta effects

What is the blood gas solubility for des?

0.42

What is the blood gas solubility for N2O?

0.46

What is the OSHA limit for exposure to halogenated agents + N20?

0.5 ppm and 25ppm respectively

What is the blood gas solubility for sevo?

0.65

For every cm above the heart MAP drops ___mmHg. For every inch it drops ___mmhg

0.74 per centimeter 2 per inch

Treatment for hypercalcemia

0.9% NaCl Loop diuretic - furosemide

What is a MAC hour?

1 MAC hour equals: -1% sevo x 2 hours -2% sevo x 1 hour -4% sevo x 30 minutes

At what point in a child's life is a cleft *lip* typically repaired? What about cleft Palate?

1 month old 12 months old

What is the dose for PLT?

1 pack per 10kg body weight

What is the dose for PRBCs?

1 unit to increase Hgb by 1 or Hct by 3%

How is *dantrolene* formulated? How is it prepared?

1 vial = 20mg dantrolene + 3mg mannitol reconstitute w/ 60mL preservative-free H20

What factors are part of the final common pathway?

1, 2, 5, 10, 13 The final common pathway can be purchased at the five and dime for 1 or 2 dollars on the 13th of the month

What is the PISS configuration for AIR?

1, 5

3 ways to inhibit acetylcholinesterase, and examples of each

1. Electrostatic attachment- competitive inhibition Ex: edrophonium 2. Formation of carbamyl esters-competitive inhibition Ex: neostigmine, pyridostigmine, physostigmine 3. Phosphorylation-Non-competitive inhibition Ex: organophosphates and echothiophate

The bourdon pressure gauge on an O2 cylinder reads 500psi. The flow rate is 4L/min. How long will the tank last?

1. 660L/1900psi = X/500psi = 174L 2. 174L/4L per min = 43.5 minutes 43.5 minutes

What are 2 common causes of angioedema? What is the treatment for each?

1. ACE-Is- Tx is Epi, antihistamines and steroids (just like anaphylaxis) 2. C1 esterase deficiency- Tx is C1 esterase concentrate or FFP

What are the 4 significant cardiac defects associated with esophageal atresia?

1. ASD 2. VSD 3. ToF 4. Coarctation of aorta

What are the 3 steps of platelet plug formation? (Primary hemostasis?)

1. Adhesion 2. Activation 3. Aggregation PLT plug is formed in ~5 minutes

Describe the flow of bile from its site of production to release into the duodenum

1. Bile is produced @ Hepatocytes 2. The Canaliculi 3. Bile Duct 4. Common hepatic duct 5. The Cystic duct (from the GB) and the Pancreatic duct joins the Common Bile duct before it empties into the Duodenum. 6. Sphincter of Oddi controls the flow of bile released from the common hepatic duct. Contraction of the sphincter of Oddi increases biliary pressure`

What are the 3 most common culprits that cause *GBS*?

1. Campylobacter jejuni bacteria 2. Ebstein-Barr virus 3. CMV

4 clinical indications for isoproterenol

1. Chemical pacemaker for bradycardia unresponsive to atropine 2. Heart transplant 3. Bronchoconstriction 4. Cor pulmonale

What are *4 LATE indicators* of MH?

1. DIC 2. Irregular rhythm 3. Cola-colored pee 4. Muscle rigidity

List 6 conditions that are NOT linked to *MH*.

1. DMD 2. Becker MD 3. Neuroleptic malignant syndrome 4. Myotonia congenita 5. Myotonic dystrophy 6. Ostogenesis imperfecta

How do you determine the appropriate distance to thread a central line or PA catheter?

1. Distance from site of entry to VC junction 2. Distance from VC junction to where the tip of catheter should be placed 3. Add these 2 #s to determine distance from site of insertion to tip of catheter

Describe the Starling forces in

1. Hydrostatic Pressure: pressure exerted by fluid Pc = capillary hydrostatic pressure - pushes fluid out of capillary Pie if- Interstitial oncotic pressure (pulls fluid out of the capillary) 2. Osmotic Pressure: pressure exerted by movement of fluid in response to solute concentration Pif = interstitial hydrostatic pressure (pushes fluid into capillary) pie-C = capillary oncotic pressure (pulls fluid into capillary)

What does the pulmonary flow volume loop look like with restrictive disease?

Shape is similar to normal loop, but the restrictive loop is smaller and shifted to the right

*MH* is definitively linked to what 3 other co-existing diseases?

1. King-Denborough syndrome 2. Central core disease 3. Multiminicore disease

How does methadone reduce pain?

1. Mu receptor agonist 2. NMDA receptor antagonist 3. Inhibits reuptake of monoamines in the synaptic cleft

What 2 mishaps can an *oxygen analyzer* detect?

1. O2 pipeline crossover 2. leak in the breathing circuit

The oxygen pressure failure device activates when what 2 circumstances occur?

1. O2 tank is exhausted 2. O2 pressure in supply line < 20psi

12 cranial nerves

1. Olfactory 2. Optic 3. Oculomotor 4. Trochlear 5. Trigeminal 6. Abducens 7. Facial 8. Vestibulocochlear (auditory) 9. Glossopharyngeal 10. Vagus 11. Spinal Accessory 12. Hypoglossal

What are the mechanisms of heat loss? Order from highest to lowest

1. Radiation(60%) 2. Convection(15-20%) 3. Evaporation (20%) 4. Conduction (<5%)

Relate the 6 stages of the cardiac cycle to the LV pressure-volume loop

1. Rapid filling (diastole) 2. Reduced filling (diastole) 3. Atrial kick (diastole) 4. Isovolumic contraction (systole) 5. Ejection (systole) 6. Isovolumic relaxation (diastole)

How does sugammadex improve safety?

1. Rocuronium can be used for difficult intubation without the drawbacks of Sch 2. It can reverse a sense neuromuscular block quickly, thus greatly reducing the risk of residual paralysis 3. It allows for a dense block until the very end of the surgical procedure without the concerns of a delayed extubation

What are *3 INTERMEDIATE indicators* of MH?

1. cyanosis 2. pt warm to touch 3. irregular rhythm

What 2 things must you do in the event of an oxygen supply line crossover?

1. Turn ON the O2 cylinder 2. Disconnect the pipeline O2 supply

How do we establish an anesthetic concentration inside the alveolus?

1. Turn the vaporizer on. This creates a concentration gradient that pushes the anesthetic agent from the vaporizer towards the alveoli. This = FI 2. Ventilation washes the anesthetic agent into alveoli = FA 3. The buildup of anesthetic partial pressure inside the alveoli is opposed by continuous uptake of agent into the blood = uptake 4. The CO distributes the anesthetic agent throughout the body. This is distribution

What are the 4 steps of hemostasis?

1. Vascular spasm 2. Formation of the platelet plug (primary hemostasis) 3. Coagulation and the formation of fibrin (secondary hemostasis) 4. Fibrinolysis when the clot is no longer needed

The risk for post-op ventilation for the *MG* patient increases in the presence of what 5 factors?

1. dz duration > 6 yrs 2. daily pyridostigmine > 750mg/day 3. VC < 2.9L 4. COPD 5. surgical approach: median sternotomy > transcervical thymectomy

A patient in need of a *Fontan* operating likely has one of which 2 diagnoses?

1. hypoplastic L heart (single RV) 2. pulmonary atresia (single LV)

What are 8 differential diagnoses to consider if *MH* is suspected?

1. thyroid storm 2. malignant neurleptic syndrome 3. sepsis 4. pheo 5. serotenergic syndrome 6. heat stroke 7. metastatic carcinoid 8. cocaine intoxication

What are 3 drawbacks of Amsorb plus?

1. lower CO2 absorbtion capacity 2. requires more frequent replacement 3. higher cost

What are 3 benefits of calcium hydroxide lime (Amsorb plus)?

1. no CO production 2. very little/no compount A production 3. lower fire risk vs. soda lime

What are *3 risk factors* for *kernicterus*?

1. prematurity 2. low plasma protein % 3. acidosis

Regarding *MH*, list 8 consequences of too much Ca+2 inside the skeletal myocyte.

1. sustained muscle contraction 2. accelerated BMR, rapid depletion of ATP 3. increased VO2 4. increased CO2 + heat production 5. mixed respiratory + lactic acidosis 6. sarcolemma breaks down 7. K and myoglobin leak into systemic circulation 8. rigidity from sustained contraction

What is the specific gravity of CSF?

1.002 - 1.009

What is the blood gas solubility for iso?

1.45

Discuss the mgmt of hypoxemia during OLV

100% FiO2 Confirm DLT position with bronchoscope CPAP 10cm H2O to non-dependent lung PEEP 5-10 cm H2O to dependent lung Alveolar recruitment maneuver Clamp PA to non-ventilated lung Resume 2 lung ventilation***

What is the treatment of laryngospasm?

100% FiO2 Remove noxious stimuli Deepen anesthesia CPAP 15-20 cm H2O Open airway- head extension, chin lift Larsen's maneuver Succinylcholine

What is the treatment of CO poisoning?

100% FiO2 until CoHgb is < 5% or for 6 hours Hyperbaric O2 if COHgb is >25% or if patient is symptomatic

What is the treatment for acute bronchospasm?

100% FiO2, deepen anesthetic- (lidocaine, VA, propofol, ketamine) Albuterol, inhaled anticholinergic (ipratropium) Epi 1mcg/kg IV Hydrocortisone 2-4mg/kg Aminophylline Heliox

For every 10 cm change, the BP changes by ___? For every inch change, the BP changes by ___?

10cm = 7.4 mmHg Inch = 2 mmHg

What is the max dose of EMLA for patient 1-6 years and >10kg?

10g Max area of application 100cm2

What is the maximum dose in mg/kg and max total dose in mg for chloroprocaine?

11mg/kg Max total 800mg

You have administered 30mg of esmolol to a patient after a sudden and profound elevation in HR. After 3 half-lives, what percentage of initial dose remains in the bloodstream?

12.5% The half time is the amount of time required for the drug concentration to decrease by 50%. Know the chart!

Exposing a gas cylinder to a temp higher than ________F/______C will cause it to explode

130 degreesF 57degreesC

When is the pregnant patient who presents for non-OB surgery at risk for aspiration?

14 weeks gestation = aspiration risk Administer an antacid (sodium citrate) within 30 min of induction, ranitidine 1 hour prior to induction, and consider reglan to facilitate gastric emptying. If mom is beyond 14 weeks gestation, secure the airway with RSI and a 6-7 ETT

What is the maximum dose in mg/kg and max total dose in mg for chloroprocaine with epi?

14mg/kg Max total 1000mg

How much cortisol is produced per day? -What is the normal cortisol level?

15-30mg/day Normal serum level of 12 mcg/dL Stress can increase cortisol production upwards of 100mg/day, with a serum level up to 30-50 mcg/dL during and after major surgery

What is the vapor pressure of sevo?

157

Class 1A MOA?

1A- moderate depression of phase 0, prolongs phase 3 repolarization Ex: Quinidine, procainamide, disopyramide

Class 1C MOA?

1C- Strong depression of phase 0, little effect on phase 3 Ex: flecainide, propafenone

What is the max dose of EMLA for patient 0-3months or < 5 kg?

1g Max area of application 10cm2

Describe the general architecture of the G protein second messenger system

1st messenger - extracellular signal Receptor- responds to signal G protein- turns off or on effector Effector- activates or inhibits the second messenger Second messenger- primary intracellular signal Enzymatic cascade Cellular response- physiologic change

Is *RA* more common in women or men?

2 - 3 x more common in women

What is the *ideal postponement for elective surgery * for a peds patient with a *URI*?

2 - 4 weeks after onset of symptoms *risk of pulmonary complications persists up to 6 - 8 weeks*

What is *familial periodic paralysis*?

2 distinct dz processes characterized by acute episodes of skeletal muscle weakness accompanied by hypo - or hyper- kalemia

Why is the risk of cardiac morbidity higher with bupivacaine than with lidocaine?

2 features determine the extent of cardiotoxicity of any LA - affinity for the receptor and rate of dissociation away from the receptor during diastole Bupivacaine has a greater affinity for the receptor, and a slower rate of dissociation away during diastole. Net result, more bupivacaine remains at the receptor for a longer period of time = more cardiac mortality and harder resuscitation

Describe the NPO guidelines

2 hours- clear liquids 4 hours- breast milk 6 hours- formula, nonhuman milk or light meal 8 hours- fried/fatty foods

What is the OSHA limit for exposure to halogenated agents ALONE?

2 ppm

Discuss fade in the context of succinylcholine and NDNMB

2 supplies of Ach vesicles -Ach that is available for immediate release -Ach that must be mobliized before it can be made available for immediate release NDNMB competitively antagonize the presynaptic Nn receptors. This impairs the mobilization process, so only the vesicles available for immediate release are able to be used. Since this is a limited quantity, nerve stimulation can quickly exhaust this supply. With each successive stimulation, less Ach is released. Clinically this manifests as fade with TOF, DBS, and tetanus Succinylcholine stimulates the prejunctional receptors- it has the same effect as Ach. When succs binds to the presynaptic Nn receptor, it facilitates the mobilization process, so there is always Ach available for immediate release. This explains why fade is not observed with succs.

What is the PISS configuration for OXYGEN?

2, 5

What coagulation factors are dependent on vitamin K? What anticoagulants are dependent on vitamin K?

2, 7, 9, 10 Anticoagulants dependent on vitamin K = Proteins C, S, Z

Which local anesthetic can reduce the efficacy of epidural opioids?

2-chloroprocaine reduces the efficacy of epidural opioids

A patient is suffering from an acute hemorrhage, and there is not time to wait for crossmatched blood. What is the next best option for this patient?

2nd best- Type specific, partially crossmatched blood 3rd- type specific uncrossmatched blood 4th- Type O- uncrossmatched blood

How does N2O affect a patient with an ocular gas bubble? When can N2O be used in these patients?

Air = Avoid N2O for 5 days SF6 bubble: Avoid for 7-10 days Perfluoropropaine = 30 days Silicone oil = no contraindication to N2O

How many cords are in the brachial plexus? Which nerve roots give rise to each cord?

3 cords- posterior, lateral and medial C5-C7 - anterior divisions of superior and middle trunks = lateral cord C8-T1 = anterior division of the inferior trunk = Medial cord C5-T1 = all 3 posterior divisions = posterior cord

What is the maximum dose in mg/kg and max total dose in mg for bupivacaine?

2.5 mg/kg Max total 175mg

Describe the *dosing of dantrolene* in the tx of *MH*

2.5mg/kg IV, repeat q5-10min stop dantrolene when s/sx of hypermetabolism subside continue in ICU at 1mg/kg q6hr or 0.1 - 0.3mg/kg/hr for 48-72hr

Pt size, cuff inflation in mL, and largest ETT that fits for LMA 2.5?

20-30kg 14ml of air in cuff Largest ETT 5.0

What is the max dose of EMLA for patient 7-12 years and >20kg?

20g Max area of application 200cm2

What is the vapor pressure of iso?

238

What is the OSHA limit for exposure to N20 ALONE?

25 ppm

What is the reference value for plasma osmolarity, and what are the 3 most important contributors?

280-290 mOsm/L 3 most important determinants sodium, glucose and BUN

Voluntary movement is a ___ neuron path. Sensory input is a ___n neuron path. Discuss each neuron with the location of its cell body?

2;3 Lower motor neuron =. Spinal cord - ventral horn Upper motor neuron = cerebral cortex - pre-central gyrus 2nd order neuron, Lemniscal system = brainstem - gracilis nucleus 2nd order neuron, Spinothalamic tract = spinal cord - dorsal horn

What is the max dose of EMLA for patient 3-12 months and > 5 kg?

2g Max area of application 20cm2

How do you dose succinylcholine in the neonate?

2mg/kg D/t relatively larger ECF

What is the maximum dose in mg/kg and max total dose in mg for levobupivacaine?

2mg/kg Max total 150 mg

What is the clinical presentation of *DMD*?

30 KAMP 30 year lifespan Kyphoscoliosis Atrophy More common in males Painless muscle degeneration

How do you treat a patient who's become hyperkalemic in response to succinylcholine?

3 goals- stabilize the myocardium, shift K into cells, and enhance K elimination Myocardium-IV Ca Shifting K- Glucose, insulin, NaHCO3, hyperventilation, albuterol Elimination-Lasix, volume, HD

What are the 3 paired and 3 unpaired cartilages of the larynx?

3 paired- cuneiform, corniculate, arytenoids 3 unpaired-thyroid, cricoid, epiglottis

5 terminal nerves at the level of the ankle. What is the origin for each nerve?

3 sensory nerves begin with S The 2 mixed sensory/motor nerves don't begin with S

How many trunks are in the brachial plexus? Which nerve roots give rise to each trunk?

3 trunks- superior, middle, inferior C5-C6 = superior C7 = middle C8-T1 = inferior

What are examples of hypertonic solutions - both crystalloids and colloids

3% NS D5NS D51/2 NS D5LR 10% dextran

What is the PISS configuration for N20?

3, 5

Pt size, cuff inflation in mL, and largest ETT that fits for LMA 3

30-50 kg 20 mL of air in cuff Largest ETT 6.0

What is the ml/kg of FRC?

35ml/kg of ideal body weight

What is the vapor pressure of N2O?

38,770

What is the maximum dose in mg/kg and max total dose in mg for ropivacaine?

3mg/kg Max total 200 mg

What is the maximum dose in mg/kg and max total dose in mg for bupivacaine with epi?

3mg/kg Max total 200mg

What are the maximum pressures and volumes for cylinders that contain air, oxygen, and nitrous?

Air- 1900 psi, 625L Oxygen- 1900 psi, 660L Nitrous- 745 psi, 1590L

List 7 ways to monitor for disconnection of the breathing circuit.

4 modalities- pressure, volume, ETCO2, vigilance Precordial stethoscope visual inspection of chest rise capnography respiratory volume monitors low expired volume alarm low peak pressure alarm Failure of bellows to rise (only with ascending)

What is the maximum pressure and volume for a cylinder containing *N20*? What about the weight of a full and empty tank, respectively?

745psi 1590L Weight - full = 20.7lb - empty = 14.1lb

In a *piston vent*, the positive pressure relief valve will open at _____________ cmH20 to prevent excessive pressure build up in the circuit

75 +/- 5

How many terminal branches are in the brachial plexus? Which roots give rise to each branch?

5 terminal branches Musculocutaneous (C5-C7) Axillary (C5-C6) Median (C5-T1) Radial (C5-T1) Ulnar (C8-T1)

Oxygen consumption falls by __-__% for every 1 degree celcius reduction in core body temperature

5 to 7 %

Pt size, cuff inflation in mL, and largest ETT that fits for LMA 1.5?

5-10 kg 7 mL air in cuff Largest ETT- 4.0

Name 3 tests of biliary duct obstruction. Which is the most specific?

5-nucleotidase (0-11u/L) is the most specific indicator of biliary duct obstruction Y-glutamyl transpeptidase (0-30u/L) Alkaline phosphatase (45-115u/L) is not very specific

Finish this sentence: When pKa and pH are the same, ________

50% of the drug will be ionized and 50% will be unionized

You are providing anesthesia for a 90kg undergoing liposuction. The plastic surgeon wants to use tumescent lidocaine 0.1% and asks you to calculate the max dose. How much tumescent lidocaine can the patient receive?

50-55ml/kg 4500-4950

Pt size, cuff inflation in mL, and largest ETT that fits for LMA 4

50-70kg 30ml of air in cuff Largest ETT 6.0

*MH* can occur as late as _______ hours after exposure to a triggering agent

6

How many divisions are in the brachial plexus? Which nerve roots give rise to each division?

6 divisions- 3 anterior/3 posterior C5-C7 = anterior divisions of superior and middle trunks C8-T1 = Anterior division of inferior trunk C5-T1 = all 3 posterior divisions

How long before surgery should you discontinue heparin?

6 hours

What Cobb Angle will result in *decreased pulmonary reserve*?

60

What is the maximum dose in mg/kg and max total dose in mg for procaine?

7mg/kg Max total 350-600mg

What is the vapor pressure of des?

669

CMRO2 decreases ___% for every 1°C decrease in temperature. For every 1mmHg change in CO2, CMRO2 will change __

7% 1-2ml/100g

What is the pKa of mepivacaine?

7.6

What is the pKa of lidocaine and prilocaine?

7.9

At what Cobb Angle will *pulmonary symptoms manifest*?

70

How is CO2 transported in the blood?

70% Bicarbonate 23% on Hgb 7% Plasma

Pt size, cuff inflation in mL, and largest ETT that fits for LMA 5

70-100kg 40ml of air Largest ETT 7.0

What is the EBV for an adult?

70ml/kg

What Cobb Angle is an *indication for surgery*?

40 - 50

What is the maximum dose in mg/kg and max total dose in mg for lidocaine?

4mg/kg Max total 300mg

What is the dose for cryo?

5 bag pool increases fibrinogen by 50mg/dl

List 4 conditions that reduce CPP as a function of increased venous pressure.

A high venous pressure decreases cerebral venous drainage and increases cerebral volume. This creates a backpressure to the brain that reduces the arterial/venous pressure gradient (MAP-CVP) Conditions that impair venous drainage include: -Jugular compression secondary to improper head positioning -Increased intrathoracic pressure d/t coughing/PEEP -Vena cava thrombosis - Vena cava syndrome

How does a hyperbaric solution distribute in the sitting patient? How about the supine patient?

A hyperbaric solution will settle to the lowest point of the spinal canal If patient remains sitting after block, hyperbaric LA will sink and anesthetize sacral nerve roots = saddle block If patient is supine after block, hyperbaric solution will slide down the lumbar lordosis and eventually pool in the sacrum and the thoracic kyphosis (T4)

How does a hypobaric solution distribute in the sitting patient? How about the supine patient?

A hypobaric solution will settle to the highest point of the spinal canal. If sitting after block, LA rises to brain = BAD Supine- solution will float toward the lower lumbar region. Will not float towards cervical region, because that would require it to sink in the thoracic kyphosis first

What is the concern about an Rh-negative mother and pregnancy?

A person who is Rh- can be sensitized by exposure to Rh+ blood during transfusion or pregnancy. An Rh- mother can be sensitized by an Rh+ fetus. Transfer occurs across the placenta. The mother receives Rhogam to prevent sensitization If the mother becomes sensitized and develops antibodies, a subsequent pregnancy with an Rh+ fetus may result in erythroblastosis fetalis

Discuss the use of pre and postductal Spo2 monitoring in the newborn.

A preductal pulse oximeter is placed on the RUE, and the postductal monitor is placed on a LE (either side) A difference between the pre-post values suggests: Pulmonary HTN, R-L cardiac shunt, or return to fetal circulation via the PDA

What is the treatment for a total spinal?

A total spinal may result from: -An epidural dose injected into the subarachnoid space -An epidural dose injected into the subdural space -A single shot spinal after a failed epidural block Treatment: Vasopressors, IVF, left uterine displacement, elevation of legs, intubation if LOC

Rank the NMB according to their likelihood of causing anaphylaxis

Succs> atracurium >cisatracurium> roc > vec

What are examples of decreased CO2 elimination?

Airway obstruction, increased dead space, Increased Vd/Vt, ARDS, COPD, Respiratory center depression, Drug overdose, Inadequate NMB reversal

Where is ADH produced and what is its function?

ADH is produced in the supraoptic and paraventricular nuclei of the hypothalamus. It is released from the posterior pituitary gland in response to increased osmolarity of the ECF and decreased blood volume. ADH increases blood pressure by increasing blood volume from V2 receptor stimulation in the collecting ducts, and increasing SVR from V1 receptor stimulation in the vasculature

Describe the autonomic innervation of the uterus

A1 = contraction B2 = relaxation

Describe the autonomic innervation of the sweat glands

A1 and M = increased secretion

Describe the autonomic innervation of the liver

A1/B2 = increased serum glucose

What second messenger system is associated with the alpha-2 receptor? What other receptors share a similar pathway?

A2- GI- stops adenylate cyclase and conversion of ATP to cAMP Other receptors- Muscarinic 2, dopamine 2 (pre-synaptic)

What hormones are released from the posterior pituitary? What are their functions?

ADH = water retention Oxytocin- uterine contraction and breast feeding

Disadvantages of Colloids

Albumin- binds Ca = hypocalcemia FDA black box warning on synthetic colloids d/t risk of renal injury Coagulopathy Dextran > hetastarch > hextend Don't exceed 20ml/kg Anaphylactic potential Highest risk = dextran

What is Conn's syndrome? How does it present?

AHH KANT PMS Aldosterone overload HTN (Na+ and water retention) Hypokalemia (K+ wasting) K+ supplementation needed Aldosterone antagonists needed Na restriction Tumor removal needed Primary - ⬆️ aldosterone release from adrenal gland Metabolic alkalosis (H+ wasting) Secondary - Usually due to increased renin release or aldosterone-secreting tumor

List the conditions that can cause left axis deviation

AI CALM Aortic Insufficiency Chronic HTN Aortic stenosis LBBB Mitral regurg

What are the anesthetic considerations for multiple system atrophy?

AKA Shy-Drager syndrome- causes degeneration of the locus coeruleus, intermediolateral column of the s.c. (where the cell bodies for the SNS efferent nerves live) and the peripheral autonomic nerves ATE -Autonomic dysfunction -Treat hypotension with volume and direct acting sympathomimetics -Exaggerated HTN with ephedrine and ketamine

What nerves are anesthetized by a psoas compartment block? What is another name for this block?

AKA lumbar plexus block Targets 3 major nerves of lumbar plexus- Blocking the LAP is blocking the LOF Lateral femoral cutaneous Obturator Femoral Block is useful when neuraxial anesthesia is contraindicated and/or anesthesia to one extremity is preferred

Pathophysiology and presentation of postintubation laryngeal edema

AKA post-intubation croup, post-intubation laryngeal edema is a complication of ETT or rigid bronch The tracheal mucosa perfusion pressure is 25 cm H2O. Using an ETT that is too large, or injecting an excessive amount of air into the cuff reduces tracheal perfusion = edema = decreased subglottic airway diameter = increased WOB Patient presents with hoarseness, barky cough, and/or stridor. Typically occurs within 30-60 minutes following extubation.

Structure and function of anterolateral system

AKA spinothalamic tract SPTIC T Sexual sensation, Pain Temperature Itch Crude touch Tickle No 2 point discrimination Smaller, myelinated, slower conducting fibers Primitive system

What is tic douloureax? What cranial nerve contributes to this problem?

AKA trigeminal neuralgia- excruciating neuropathic pain in the face Trigeminal nerve

What patient populations are at risk for developing hyperkalemia following succinylcholine?

ALS Charcot-Marie-Tooth DMD GB Hyperkalemic periodic paralysis MS Upregulation of extrajunctional receptors (burns, denervation injury)

Which anesthetic techniques can be used to maintain hepatic blood flow

ANAL R Avoid PEEP Normocapnia Avoid Halothane Liberal IVF RA is fine as long as there are no coagulation defects

How does diabetes mellitus affect the autonomic nervous system?

ANS dysfunction -painless MI -Reduced vagal tone- tachycardia -Risk of dysrhythmias -Orthostatic hypotension -Impaired respiratory compensation to hypoxia and hypercarbia = increased sensitivity to anesthetic drug Delayed gastric emptying - increased risk of aspiration Impaired thermoregulation = increased risk of hypothermia RA may worsen neurologic defect in the patient with diabetic polyneuropathy Diarrhea and constipation

Calculate the Apgar score

APGAR Appearance(Color):A bit pink, extremities blue = 1 Pulse(HR): <100 = 1 Grimace(reflex irritability): = 1 A(Muscle tone): A little flexion = 1 R(Respirtory effort): Slow irregular = 1 0 is none 1 is some 2 is good

Categories of aldrete score

ARCCS Activity Respiration Circulation Consciousness Skin color

How do you treat a patient with ATIII deficiency?

AT III concentrate or FFP Common cause for failure to achieve anticoagulation despite adequate heparin dosing prior to CPB

What is truncus arteriosus?

AV OD Artery that gives rise to the pulmonary, systemic, and coronary circulations. VSD as well Only one artery = no specific pathway for blood to enter the pulmonary circulation Decreasing PVR or increasing pulmonary flow steals blood from systemic and coronary circulations

What are the s/s and treatment for Alcohol Withdrawal Syndrome?

AWS: 6-8 hours after the BAC returns to near normal. Symptoms peak @ 24-36 hours. Early- tremors, disordered perception (hallucinations, nightmares) Late- Increased SNS activity- tachycardia, HTN, dysrhythmias, N/V, insomnia, confusion, agitation. Treatment- ETOH, BB, A2 agonists

List 3 examples of GIIb/IIIa receptor antagonists, and state how long each must be discontinued prior to surgery

Abciximab - 3 days Eptifibatide - 1 day Tirofiban - 1 day Tiros Fibin Epcot for 1 day was better than 3 days having Ab Sexi Mab

How does a flow volume loop appear with an extrathoracic obstruction?

Abnormal during inspiration, normal during expiration

5 risk factors for difficult invasive airway placement

Abnormal neck anatomy Obesity Short neck Limited access to cricothyroid membrane (halo, neck flexion issue) Laryngeal trauma

What is afterload, and how do you measure it in the clinical setting?

Afterload is the force the ventricle must overcome to eject the SV. -In the clinical setting, we use SVR as a surrogate for LV afterload

What is the difference between placenta accreta, increta, and percreta? What is the major risk that these complications present?

Accreta- attaches to the surface of the myometrium Increta- Invades the myometrium Percreta-extends beyond the uterus (P = Pelvis) Uterine contractility is impaired and there is potential for tremendous blood loss. Neuraxial is safe, but GA is preferred.

What is the tx for both HYPER and HYPOkalemic periodic paralysis?

Acetazolamide - creates a non-gap acidosis which protects against hypokalemia; also facilitates renal K excretion, which protects against hyperkalemia

How do cholinesterase inhibitors reverse paralysis caused by a NDNMB?

Acetylcholinesterase hydrolyzes Ach into choline and acetate. This enzyme is concentrated around the nicotinic receptors at the NMJ Drugs such as edrophonium, neostigmine, and pyridostigmine reversibly inhibit AchE, which indirectly increases the concentration of Ach at the NMJ. Since more Ach is present, it is better able to compete for the alpha binding sites on the nicotinic receptor and antagonize the block.

How is the Ach signal "turned off" at the NMJ?

Acetylcholinesterase is strategically positioned around the pre and postsynaptic nicotinic receptors; it hydrolyzes Ach almost immediately after it activates the receptors

What happens when Ach activates the post-synaptic, nicotinic receptor at the NMJ?

Ach binds to the alpha units of the receptor (1 Ach at each of the 2 alpha subunits). This prompts the channel to open. Na and Ca enter the cell, K exits the cell At rest, the inside of the muscle cell is negative relative to the outside of the cell. When the Nm receptor is activated by Ach, Na flows down it's concentration gradient and enters the cell. This makes the cell interior more positive, activates voltage-gated sodium channels, depolarizes the muscle cell, and initiates an AP Depolarization of the myocyte instructs the ER to release Ca into the cytoplasm, where it engages with the myofilaments and initiates muscle contraction

Which anesthetic agents have been implicated in apoptosis? What drugs are NOT?

Agents that have been implicated in apoptosis tend to antagonize the NMDA receptor, stimulate the GABA receptor, or both Opioids, Dexmedetomidine, Xenon

What conditions can cause right axis deviation?

Acute bronchospasm COPD Cor pulmonale Pulm HTN PE

Is the patient with acute hepatitis a candidate for surgery? -How about if had chronic hepatitis?

Acute hepatitis- non-emergent surgery should be postponed until symptoms have resolved and LFTs have returned to normal. Chronic- patient may proceed to surgery as long as they are stable.

Give examples of intrinsic lung diseases (acute and chronic)

Acute: Red Rover, Come Over, Now! *******! Reversal of opioid overdose, Re-expansion of collapsed lung, Cocaine, Obstruction(upper airway), Neurogenic, Aspiration, NPPE Chronic- pulmonary fibrosis, sarcoidosis

How does fluorination affect the physiochemical characteristics of halogenated anesthetics?

Adding fluoride ions tends to decrease potency, increase vapor pressure, and increase resistance to biotransformation *Sevo is heavily fluorinated, but still 3x more potent than des, d/t bulky propyl side chain

Etiologies of metabolic alkalosis

Addition of HCO3- D/t HCO3 administration, or massive transfusion (liver converts preservatives to HCO3) Loss of Nonvolatile acid- Loss of gastric fluid, vomiting, NG suction, loss of acid inurine, diuretics, ECF depletion Increased mineralocorticoid activity- Cushing's syndrome, hyperaldosteronism

What is Acute Adrenal Crisis? How does it present?

Additional stress (infection, illness, sepsis, surgery) exacerbates adrenal insuficiency Hemodynamic instability- collapse Impaired mental status Fever Hypoglycemia

What is the level of the conus medullaris and subarachnoid space in an adult? In an infant?

Adult = L1-L2 and S2 for Subarachnoid space. Infant = L3 and S3 for Subarachnoid space. BaBEE is L3 & S3

Why does HgbF have a higher affinity for O2?

Adult Hgb = 2 α & 2 β chains Fetal Hgb = of 2 α and 2 γ chains -The β chains are the binding site for 2,3 DPG → Infants don't have these beta chains so they can't bind 2,3 DPG. This shifts the curve to the left, which increases the affinity for oxygen

What conditions cause the loss of the a wave on the CVP waveform?

Afib V-pacing if underlying rhythm is asystole

What are the immediate term effects of smoking cessation?

After 6 weeks = return of E MAPS EMAPS Enzyme induction subsides Mucociliary clearance Airway function Pulmonary immune function. Sputum production

When does a patient with SCI become at risk for autonomic hyperreflexia? What factor (other than time) contributes to this risk?

After the neurogenic shock phase ends (1-3 weeks), the body begins to mend itself in a pathologic and disorganized way. There is a return of spinal sympathetic reflexes below the level of the injury, but without inhibitory influences that would normally come from above the level of injury, the SNS reflexes below the level of injury exist in an overactive state. Up to 85% of patients with injury above T6 will develop AH, it is very unlikely to occur in patients with an injury below T10. The higher the injury = more intense response

How is sugammadex metabolized?

Sugammadex and the sugammadex-rocuronium complex are excreted unchanged by the kidneys

Where is aldosterone produced, and what is its function?

Aldosterone is a steroid hormone that is produced in the zona glomerulosa of the adrenal gland By stimulating the Na/K ATPase in the principal cells of the distal tubules and collecting ducts, aldosterone causes sodium and water reabsorption, and potassium excretion. Net effect = aldosterone increases blood volume but doesn't change osmolarity. Water follows sodium in direct proportion when its reabsorbed.

How does the kidney contribute to the volume and composition of the extracellular fluid

Aldosterone- controls ECF volume (Na + H2O are reabsorbed together) ADH-controls plasma osmolarity- water is reabsorbed, Na is not The kidneys also regulate potassium, chloride, phosphate, magnesium, hydrogen, bicarbonate, glucose and urea

What physiologic disturbances result from massive transfusion?

Alkalosis- citrate is metabolized to bicarb in the liver Hypothermia Hyperglycemia from dextrose in stored blood Hypocalcemia from binding of calcium by citrate Hyperkalemia from administration of older blood

What is the unitary hypothesis?

All anesthetics share a similar mechanism of action, although each may work at a different site

What coagulation factors are NOT produced by hepatocytes?

All but Calcium are made in endothelial cells which line the inside surface of blood vessels, and bone marrow cells. vWF Factor 3 Factor 4 Factor 8 3 whores 8 out Von Willibran

What second messenger system is associated with the alpha-1 receptor? What other receptors share a similar pathway?

Alpha 1- GQ- Phospholipase C- IP3 + CA+ DAG Other receptors- histamine 1, muscarinic 1, muscarinic 3, muscarinic 5, vasopressin 1

How does the production of plasma proteins change in the elderly?

Alpha 1-acid glycoprotein = increases...."think aag increases with age.." Albumin= decreases Pseudocholinesterase = decreases- increased succs duration (Men > women)

How does dexmedetomidine produce analgesia?

Alpha-2 stimulation in the dorsal horn of the spinal cord = decreased substance P and glutamate release

What is the difference between alpha-stat and pH-stat blood gas measurement during CPB?

Alpha-stat- does not correct for patient's temperature. This technique aims to keep intracellular charge neutrality across all temperatures. It is associated with better outcomes in adults. pH-stat corrects for temperature. This technique aims to keep a constant pH across all temperatures. This is associated with better outcomes in peds.

RBC storage lesion

Although the CDPA preservative extends the life of banked blood, there are several important changes that occur during storage- AKA RBC storage lesion -Decreased 2,3 DPG -Decreased ATP -Decreased pH -Increased K -Impaired ability to change shape -Hemolysis -Increased production of proinflammatory mediators

What is the difference between Cushing's syndrome and Cushing's disease?

Although they present similarly, the etiologies are a little different. Cushing's syndrome = too much cortisol Cushing's disease = too much ACTH

What does the alveolar compliance curve tell you?

Alveolar ventilation is a function of alveolar size and its position on the alveolar compliance curve Best ventilated- alveoli that are most compliant- on the steep slope of the curve Poorest ventilated are the least compliant- flattest portion of the curve ** ventilation is greatest at the lung base due to high alveolar compliance**

Describe the hemodynamic management of the patient with pheochromocytoma

Always alpha block first!!! Alpha-antagonists Nonselective- phenoxybenzamine and phentolamine Alpha-1 selective- doxazosin and prazosin

Which regulatory agency sets the standards for the required components of the anesthesia machine with the ASTM F1850 document?

American Society for Testing and Materials

What is the role of the liver and amino acid deamination? What happens when the liver is unable to perform this function?

Amino acid deamination allows the body to convert proteins to carbohydrates and fats. Some of these are utilized in Kreb's cycle to produce ATP Deamination process produces a large quantity of ammonia. Liver converts ammonia to urea, which is eliminated by the kidney. Failure to clear ammonia leads to hepatic encephalopathy.

What test can be done to assess fetal lung maturity in utero? What value suggests adequate lung development?

Amniocentesis can assist in the determination of fetal lung development L/S ratio gives advance ratio about the state of fetal lungs by providing the ratio of lecithin (surfactant) to sphingomyelin (surfactant precursor) L/S > 2 suggests adequate lung development

In what regions of the brain do halogenated anesthetics produce amnesia?

Amygdala Hippocampus

What's behind the confusion of DMD being mistakenly linked to *MH*?

An MH-like syndrome is associated w/ DMD, but it is d/t rhabdomyolosis - NOT true MH Pt w/ DMD has a normal RyR1 receptor

What is an action potential, and how does it depolarize a nerve?

An action potential is a temporary change in transmembrane potential followed by a return to transmembrane potential -In order for a neuron to depolarize, sodium must enter the cell (inside cell more +) - Once threshold potential is achieved, the cell depolarizes and propagates an action potential -Depolarization is all or none- either cell depolarizes or it doesn't -The AP only travels in one direction, because Na channels in upstream portion of the neuron are in closed/inactive state

Discuss the significance of the alpha and beta angles on the capnograph

An increased alpha angle signifies an expiratory airflow obstruction- COPD, bronchospasm, kinked ETT The beta angle is increased in most etiologies of rebreathing. It is specific to rebreathing d/t a faulty unidirectional valve, but will appear normal in case of exhausted CO2 absorbent.

What conditions increase pulmonary resistance? How does this affect peak pressure and plateau pressure?

An increased pulmonary resistance is usually due to a reduction in dynamic compliance (PIP increases, and PP is unchanged) Ex: kinked ETT, ETT cuff herniation, bronchospasm, bronchial secretions, compression of airway, FB aspiration

Why is it more difficult to place a neuraxial block in the elderly?

Anatomic changes make it more difficult to place a neuraxial block in the elderly: Less space between posterior spinous processes Decreased intravertebral disc heigh Narrow intervertebral foramen Calcification of joints

How do you block the median nerve at the wrist?

Anatomic landmarks- flexor carpi radialis tendon, flexor palmaris longus tendon Inject 5mL between the 2 tendons

How do you block the radial nerve at the wrist?

Anatomic landmarks- radial styloid Where to inject- SubQ, 10mL proximal to radial styloid. Field block is used because there are several branches of the radial nerve at this point in the wrist

How do you block the ulnar nerve at the wrist?

Anatomic landmarks- ulnar styloid, ulnar pulse, flexor carpi ulnaris tendon Where to inject- 3-5 ml medial to and below the flexor carpi ulnaris tendon. Confirm negative aspiration prior to injection d/t proximity to ulnar artery

Provide an example of each type of dead space

Anatomic- Nose/mouth to terminal bronchioles Alveolar- reduced pulmonary blood flow Physiologic- anything that increases anatomic or alveolar dead space Apparatus- facemask, HME, limb of circle system if incompetent valve present

Define the 4 types of dead space

Anatomic- air confined to the conducting airways Alveolar- alveoli that are ventilated but not perfused Physiologic- Anatomic + Alveolar Apparatus- dead space added by equipment

What are *hematologic complications* of *RA*?

Anemia Plt dysfxn secondary to NSAIDs

How long should elective surgery be delayed in the patient with a bare metal stent? Drug eluting stent? s/p angioplasty? s/p CABG?

Angioplasty with no stent: 2-4 weeks Bare metal 30 days (3 months preferred) After CABG: 6 weeks (3 months preferred) Drug eluting: -Second gen 6 months -First gen 12 months After ACS: 12 months minimum

Describe the pharmacologic prophylaxis of aspiration pneumonitis

Antacids- sodium citrate, NAHCO3 H2 angagonists- ranitidine, famotidine GI stim- reglan PPI- omeprazole, lansoprazole Antiemetics-droperidol, ondansetron

Describe the anterior and posterior circulation of the brain. Where do these pathways converge?

Anterior circulation- Internal carotid arteries supply the anterior circulation. They enter the skull through the foramen lacerum Aorta- Carotid artery-Internal carotid artery - CoW- cerebral hemispheres Posterior circulation-vertebral arteries supply the posterior circulation. They enter the skull through the foramen magnum. Aorta - subclavian artery - vertebral artery - basilar artery - posterior fossa structures and cervical spinal cord

How does the hypothalamus communicate with the anterior pituitary gland? How does it communicate with the posterior pituitary gland?

Anterior pituitary- via releasing and inhibiting hormones Posterior- via neural connections

Where is the superficial peroneal nerve blocked?

Anterior to the lateral malleolus Superficial peroneal is at 02:00

Where is the saphenous nerve blocked?

Anterior to the medial malleolus Saphenous at 11:00

What conditions decrease insulin release

Anything that decreases serum glucose will also decrease insulin release

What things impair HPV and what are the consequences of this?

Anything that increases shunt Halogenated anesthetics PDE-I Dobutamine Vasodilators

What factors influence FRC?

Anything that reduces outward lung expansion or reduces lung compliance Increased abd pressure- obesity, pregnancy Positioning

List 3 conditions that set afterload proximal to the systemic circulation

Aortic stenosis, hypertrophic cardiomyopathy, coarctation of the aorta

Name 3 types of machines with *piston ventilators*

Apollo Fabius Narkomed 6000

How does arterial compliance change in the elderly?

Arterial compliance decreases as a function of loss of elastin and increased collagen. Increase SVR = increase BP Increase pulse pressure Increased myocardial wall tension to overcome higher afterload Increased myocardial hypertrophy

Describe the autonomic innervation of the vasculature

Arteries - A1 >A2 vasoconstriction Veins- A2 >A1 vasoconstriction Myocardium and skeletal muscle- B2 = vasodilation Renal and Mesenteric- DA = vasodilation

Describe the sensory innervation of the upper extremity

As a general rule The ventral portion is supplied by the median, ulnar, and musculocutaneous nerves (lateral/medial cords) Dorsal portion is supplied by the radial and axillary nerves (posterior cord) Hand is the exception

Discuss the management of patients with NEC

B BMS Bowel resection early in life can lead to short gut syndrome Bowel resection and usual colostomy. Metabolic acidosis Substantial fluid replacement

What is the order of nerve block onset?

B fibers C fibers A Gamma and delta fibers A Alpha and beta fibers

How does cirrhosis affect liver blood flow? What is the consequence of this?

As the number of hepatocytes dwindles, so does the liver's ability to perform all of its essential functions. The number of blood vessels passing through the liver is reduced, which increases hepatic vascular resistance (Portal HTN) To partially offset the increased resistance, the body creates collateral vessels that bypass the liver. This are called portosystemic shunts. Since this blood bypasses the liver, drugs and toxins (ammonia) remain in the systemic circulation for a longer period of time.

How does the site of measurement affect the BP reading?

As the pulse moves from the aortic root towards the periphery, the systolic pressure increases, diastolic pressure decreases, and pulse pressure widens. MAP is constant throughout the arterial tree At the aortic root - SBP is lowest, DBP is highest, and PP is narrowest At dorsalis pedis- SBP is highest, DBP is lowest, and PP is widest

Characteristics of DI

Associated with pituitary surgery (most common), TBI, SAH Presents as polyuria Hypovolemia, hypertonic osmolarity, high plasma Na High UOP, normal urine Na Treatment- DDAVP or vasopressin, supportive

How does pregnancy affect uterine blood flow?

At term, uterine blood flow increases to 500-700 mL/min (10% of CO)

What is the most common airway complication of *RA*?

Atlantoaxial subluxation

Discuss the metabolism of benzylisoquinolinium NMB

Atracurium- Hofmann elimination (33%) and non-specific plasma esterases (66%) Cisatracurium- Hofmann elimination only Mivacurium is metabolized by pseudocholinsterase (same as succs)

What is the most common dysrhythmia associated with mitral stenosis?

Atrial fibrillation

Which antimuscarinics pass through the BBB? Which do not? Why?

Atropine and scopolamine are naturally occurring tertiary amines. Because they are lipophilic, they easily cross lipid membranes including the BBB, GI tract, and placenta Glyco-quarternary ammonium-ionized, cannot cross BBB/placenta

Compare and contrast the SE of atropine, scopolamine, and glycopyrrolate

Atropine- increases HR the most Scopolamine- highest sedation, antisialagogue, mydriasis/cycloplegia, and prevention of motion-sickness Glyco-Increases HR medium, medium antisialagogue

Describe the autonomic influence on the newborn's heart

Autonomic regulation of the heart is immature at birth, with the SNS being less mature than the PNS. Stressful situations, such as DL or airway suctioning may cause bradycardia. Atropine may be administered prior to induction to mitigate this response. Additionally, the baroreceptor reflex is poorly developed, so the reflex fails to increase HR in the setting of hypovolemia.

Describe the pathophysiology of *Marfan syndrome*

Autosomal dominant trait Connetive tissue d/o a/w increased risk of: MARFAN got all the heart stuff MVP Aortic dissection (can extend to pericardium, inc. risk of tamponade) Regurg Aortic & Mitral

What is the risk of NSAIDs when used in the pregnant patient?

Avoid NSAIDs after the first trimester, they may close the ductus arteriosus

What are the hemodynamic goals for the patient with left to right shunt (acyanotic)?

Avoid increased SVR Avoid decreased PVR - decrease FiO2 - hypoventilation

How can you reduce the risk of airway complications while anesthetizing a child with a URI?

Avoid mechanical irritation of airway- Facemask >LMA>> ETT. Mechanical irritation increases risk of bronchospasm x 10 If an ETT must be used, use a smaller size, higher risk for post-intubation croup Dexamethasone Ensure deep anesthesia before instrumentation of the airway Propofol attenuates airway reactivity and may reduce the risk of bronchospasm Sevoflurane is the best VA d/t not pungent

Which anesthetic agents should be avoided in the hyperthyroid patient?

Avoid sympathomimetics, anticholinergics, ketamine and pancuronium

What is the best way to secure the airway in a patient with a large goiter?

Awake intubation Next best choice- technique that maintains spontaneous ventilation

What is the best way to secure the airway in a patient with Ludwig's angina?

Awake nasal intubation Awake tracheostomy

What is baricity and how does it influence your selection of LA?

Baricity describes the density of a LA solution relative to CSF. Isobaric- baricity similar to CSF Higher density = hyperbaric Lesser density = hypobaric

What reflex can be activated during CEA or following carotid balloon inflation?

Baroreceptor reflex

What factors impact Hofmann elimination?

Base-catalyzed reaction dependent on normal blood pH and temperature -Faster → Alkalosis and hyperthermia -Slower → Acidosis and hypothermia

How do you treat PDPH?

Bed rest Hydration NSAIDs Caffeine Epidural blood patch

Plasma protein binding in the neonate

Before 6 months of age, there are lower concentrations of albumin and alpha-1 acid glycoprotein Highly protein bound drugs will display higher free drug levels which increases the risk of toxicity

Describe the autonomic innervation of the heart

B1 = increased contractility, HR and CV M2 = decreased contractility, HR and CV SNS- cardiac accelerator fibers arise from T1-T4 PNS- vagus- CN X

What second messenger system is associated with the beta-1 and beta-2 receptor? What other receptors share a similar pathway?

B1 or B2- GS- Stimulates adenylate cyclase, allows conversion of ATP to cAMP Other receptors-Histamine 2, vasopressin 2 (renal), dopamine 1 (Post-synaptic)

Describe the autonomic innervation of the bronchial tree

B2 = bronchodilation M3 = bronchoconstriction **B2 are not innervated. They respond to circulating catecholamines or inhaled to airway

Discuss the prevention of premature delivery?

BAT away premature delivery! Betamethasone: Hastens fetal lung maturity. Take effect in 18 hours. Peak @ 18 hours. Seldom given after 33 weeks gestation. (Beta 🔊 like Eight...Peak at Eighteen hours...) ABX prophylaxis: for Chorioamnionitis is also given. Tocolytics: Halts labor for 24-48 hours. Seldom given after 33 weeks gestation. They provide the bridge that allows the corticosteroids time to work.

What is intrinsic sympathomimetic activity? What drugs exert this effect?

BB that exert a partial agonist effect, while simultaneously blocking other agonists that have a higher affinity for the beta receptor are said to have intrinsic sympathomimetic activity. Examples- labetolol and pindolol

5 risk factors for difficult mask ventilation

BONES Beard Obese No teeth Elderly Snoring hx

How do the blood pressure and pulse pressure change in the elderly?

BP increases as a function of reduced arterial compliance (Increased SVR) Pulse pressure is also increased for the same reason.

Describe the A&P of the baroreceptor reflex

BRR regulates short term BP control. When the BP rises, the BRR decreases HR, contractility and SVR. When blood pressure falls, the BRR increases HR, contractility and SVR. Long term BP control is mediated by the RAAS and ADH

List 3 tests of GFR and give the normal values for each

BUN 10-20 mg/dl Serum creatinine 0.7-1.5mg/dL Creatinine clearance 110-150 mL/min

What bedside exam can assess the integrity of the corticospinal tract? -How do you interpret it?

Babinski test- a firm stimulus is applied to the underside of the foot yields the following responses Normal- downward motion of all toes Upper motor neuron injury- Upward extension of the big toe, fanning of other toes Lower motor neuron- no response

What are the most common side effects of an epidural blood patch?

Backache Radicular pain

What factors do NOT significantly affect the spread of LA in the subarachnoid space?

Barbotage Increased intra-abdominal pressure Speed of injection Orientation of bevel Weight Addition of a vasoconstrictor Gender

What is Bell's palsy? What cranial nerve contributes to this problem?

Bell's palsy results from injury to the facial nerve Causes ipsilateral facial paralysis

How do you dose the reversal agent with CKD

Both anticholinesterases and anticholinergics used to reverse NMB undergo renal elimination, and thus share a similar increase in action. Neither require dose adjustments.

What is the difference between osmolarity and osmolality?

Both are measures of concentration- the amount of solvent within a defined space Osmolarity- measures the number of osmoles per liter of solvent. Larry measure osmoles Liter Osmolality- number of osmoles per kg of solvent.

What does the pulmonary flow volume loop look like with a fixed obstruction?

Both inspiration and expiration are affected.

Do the elderly require a dosage adjustment for intrathecal or epidural anesthesia? Why?

Both require dose adjustment Intrathecal- CSF volume is reduced = greater spread of LA Epidural- volume of epidural spaace is reduced = greater spread of LA

What is the primary hemodynamic concern when a small child receives a second dose of succinylcholine?

Bradycardia or asystole IV atropine (0.02mg/kg) will mitigate the response

How does succinylcholine affect heart rate? Why?

Bradycardia or tachycardia -Bradycardia or systole by stimulating the M2 receptor on the SA node (a second dose of Sch increases this risk) -Succinylmonocholine (metabolite of Sch) is responsible for this bradycardia -Antimuscarinics may prevent or revers these bradyarrhythmias Tachycardia -Sch can cause tachycardia and HTN by mimicking the action of Ach -Tachycardia is more common with adults than bradycardia

What are the CV effects of dexmedetomidine?

Bradycardia/hypotension

What is the key function of the proximal tubule?

Bulk reabsorption of solutes & water "PCT = RE absorb ME!"

Compare and contrast bupivacaine and ropivacaine for labor

Bupi: Racemic Cardiac toxicity common with R-enantimer Cardiac toxicity before seizures Minimal tachyphylaxis Low placental transfer d/t high PB and ionization Greater sensory & motor block Ropi: S isomer of bupi w/ sub of propyl group Cardiac risk less Potency is less Less motor block

List the SE common to acetylcholinesterase inhibitors

By increasing the concentration of Ach at the muscarinic receptor, AchE inhibitors cause a predictable set of parasympathetic effects

How does neuraxial anesthesia affect the neuroendocrine response to stress?

By inhibiting the afferent traffic originating from the surgical site, neuraxial anesthesia diminishes the surgical stress response. This reduces circulating levels of catecholamines, renin, angiotensin, glucose, TSH and GH

What are the risk factors for propofol infusion syndrome?

C PISS Children > adults Propofol dose >4mg/kg/hr (67mcg/kg/min). Propofol infusion >48 hours Inadequate O2 delivery Sepsis Significant cerebral injury

4 substances that extend the shelf life of RBCs. What is the function of each?

Citrate- anticoagulant Phosphate- buffer that combats acidosis Dextrose- substrate for glycolysis Adenine- helps RBCs re-synthesize ATP

What is the MOA for class 1 anti-dysrhythmics.?

Class 1 = Na channel blockers 3 sub-classes

What are the s/s and treatment for Delirium Tremens?

DT: Occurs after 2-4 days without alcohol s/s- grand mal seizures, tachycardia, HTN or hypotension, combativeness Tx- diazepam (benzos) and BB

What are the *airway complications* of *SLE*?

CHARS Cricoarytenoiditis Hoarseness Airway obstruction RLN palsy Stridor,

What are *4 indications for surgical repair* in the patient with *coarctation of the aorta*?

CHIL Chest pain Headaches Intolerance of exercise Lower extremity claudication

Describe the MOA, clinical use, and key side effects of carbonic anhydrase inhibitors

CAI- acetazolamide, dorzolamide MOA- noncompetitive inhibition of CA in the proximal tubule = net loss of HCO3 and Na with a net gain of H+ and Cl- Uses- open angle glaucome, altitude sickness, central sleep apnea syndrome Key side effects- metabolic acidosis, hypokalemia

What conditions cause an increased A wave on the CVP waveform?

CAMP DAT J Chronic lung disease leading to RV hypertrophy AV dissociation MI PVCs Diastolic dysfunction Asynchronous V pacing Tricuspid stenosis Junctional rhythm

What are 3 ways *rheumatoid arthritis (RA)* affects the airway?

CAT Cricoarytenoid arthritis, AO instability TMJ synovitis

What is the formula for cerebral blood flow? What are the normal values for global, cortical, and subcortical flow?

CBF = CPP/cerebral vascular resistance Global 45-55 ml/100g/min - 15% of CO Cortical- 75-80mL/100g/min Subcortical 20ml/100g/min

Co-administration of which antiarrhythmic with dantrolene can precipitate life-threatening hyperkalemia?

CCB

What is the cause of bradycardia with neuraxial anesthesia?

Caused by blockade of preganglionic cardioaccelerator fibers at T1-T4. This promotes a relative increase in PNS tone Unloading of cardiac mechanoreceptors (Bezold-Jarisch reflex) Unloading of the stretch receptors in the SA node

Pathophysiology of restrictive pericarditis?

Caused by fibrosis or any condition where the pericardium becomes thicker - During diastole, the ventricles cannot fully relax, this reduces compliance and limits diastolic filling. Ventricular pressures increase, which creates a backpressure to the peripheral circulation. The ventricles adapt by increasing myocardial mass, but over time this impair systolic function

Type 1 and type 2 heparin induced thrombocytopenia

Causes clot formation throughout the body HIT occurs when the body mounts an immune response against heparin after it binds to PLT factor 4. IgG antibodies activate PLTs, which ultimately results in uncontrolled clot formation. The PLT count falls because PLT are consumed faster than they are produced. Type 2 is the worst to have

How is cell saver blood different from PRBC's?

Cell saver blood has a higher concentration of 2,3 DPG and ATP, so CaO2 is greater and the cells are better able to maintain their biconcave shape (less sludging in the microcirculation)

What increases the patient's susceptibility to microshock?

Central line, PAC and pacing wires

What complication can result when hypertonic saline is administered too quickly?

Central pontine myelinolysis

In what regions of the brain do halogenated anesthetics produce unconsciousness?

Cerebral cortex Thalamus RAS

How does the cerebral oximeter work? What value is considered a significant change from baseline?

Cerebral oximetry utilizes near infrared spectroscopy (NIRS) to measure cerebral oxygenation Cerebral oximetry relies on the fact that the cerebral blood volume is 1 part arterial to 3 parts venous NIRS does not have the ability to detect pulsatile blood flow- it is primarily a measure of venous oxyhemoglobin saturation and oxygen extraction A >25% change from baseline suggests a reduction in cerebral oxygenation

What is the most significant source of morbidity and mortality in the patient with SAH?

Cerebral vasospasm is a delayed contraction of the cerebral arteries. It can lead to cerebral infarction. Free Hgb that is in contact with the outer surface of the cerebral arteries increases the risk of vasospasm. Indeed, there is a positive correlation between the amount of blood observed on CT and the incidence of vasospasm.

What regional technique can be used for the patient undergoing CEA? What levels must be blocked?

Cervical plexus block- C2-C4

What is the formula to measure compliance?

Change in volume/Change in pressure

What is cirrhosis?

Characterized by cell death, where healthy hepatic tissue is replaced by nodules and fibrotic tissue. This reduces the number of functional hepatocytes and the number of sinusoids.

Describe the pathophysiology of DIC

Characterized by disorganized clotting and fibrinolysis that lead to the simultaneous occurence of hemorrhage and systemic thrombosis Generalized thrombin formation creates microvascular clots that impair tissue perfusion, resulting in tissue hypoxia and acidosis. The body attempts to break down these clots by activating its anticoagulant system, however this leads to widespread consumption of clotting factors, fibrinogen, and PLT.

Define restrictive lung disease

Characterized by: -Impaired lung expansion -Decreased lung volumes -Normal pulmonary flow rates

What is Mendelson's syndrome?

Chemical aspiration pneumonitis first described in OB patients receiving inhalational anesthesia Gastric pH < 2.5, Gastric volume >25mL (0.4ml/kg)

How does chest wall compliance change in the elderly?

Chest wall compliance decreases. The chest is stiffer and more difficult to expand. This is caused by: Flatter diaphragm Increased A:P diameter Increased intercostal muscle mass Joint calcification Loss of intervertebral disc height

What LA reduces the effectiveness of opioids in the epidural space?

Chloroprocaine

Which hormone stimulates bile release? What is the stimulus for release?

Cholecystokinin (CCK) stimulates GB contraction and increases the flow of bile into the duodenum. Production and release = duodenum Release d/t food ingestion (fat and amino acids) and increased PNS tone

Discuss the presentation and pathophysiology of autonomic hyperreflexia

Classic = HTN + bradycardia Vasoconstriction below level of injury, vasodilation above level of injury. Other s/sx = nasal stuffiness, HA, blurry vision, severe HTN = CVA, seizure, LVF, dysrhythmias, pulmonary edema, MI

What is the relationship between neuraxial anesthesia and MS?

Classic teaching = epidural is safe, spinal may exacerbate symptoms. No supporting data.

Discuss the use of phenylephrine and ephedrine in the laboring patient

Classic teaching states that phenylephrine increases uterine vascular resistance and reduces placental perfusion. More recent evidence suggests that phenylephrine is as efficacious as ephedrine in maintaining placental perfusion and fetal pH in healthy mothers. Mothers that received phenylephrine had higher fetal pH values (less fetal acidosis)

What is the clinical presentation of propofol infusion syndrome?

Clinical presentation includes acute refractory bradycardia leading to asystole + at least one of the following. RR HELM Rhabdo Renal failure HLD Enlarged or fatty liver Lipemia (cloudy plasma/blood)- may be an early sign Metabolic acidosis (base deficit > 10 mmol/L)

What drugs can be added to LA to provide supplemental analgesia? What is the MOA?

Clonidine- A2 agonist Epinephrine A2 agonist Opioids- Mu2 agonist

How do you treat the patient with an intracerebral bleed who is on clopidogrel?

Clopidogrel, ASA, or both can be reversed with PLT transfusion. Also evidence of reversal with recombinant factor VIIa.

What drugs can be used to close the ductus arteriosus? What can be used to keep it open?

Closed with indomethacin Opened with PGE1

Under normal conditions, why does blood remain a liquid?

Coagulation proteins circulate in the inactive form Endothelium is smooth, glycocalyx repels clotting factors Undamaged endothelium does not express tissue factor or collagen. This prevents activation of PLT and the coagulation cascade. Activated factors are removed by brisk blood flow through the vessels as well as anticoagulants in circulation.

What is the lethal triad of trauma?

Coagulopathy Hypothermia Acidosis

What factors increase MAC?

Coke 2 Hyper Cat's Youth

What are the effects of lidocaine at 15-25mcg/ml?

Coma, respiratory arrest

What structures lie within the carotid sheath?

Common carotid Internal carotid Internal jugular Vagus nerve

What are the FGF recommendations for sevoflurane? Why is this?

Compound A is produced when sevoflurane is degraded by soda lime. FDA recommends that sevoflurane be administered at a rate of 1 L/min for no more than 2 MAC hours. After 2 MAC hours have elapsed, the FGF should be increased to 2L/min

How does the heart compensate for pressure overload?

Concentric hypertrophy- sarcomeres added in parallel

Define dromotrophy

Conduction velocity- how fast the action potential travels per time

A patient has a hernia at the foramen of Bochdalek. What congenital condition does this patient have?

Congenital diaphragmatic hernia is a diaphragmatic defect that allows the abdominal contents to enter the thoracic cavity. The foramen of Bochdalek is the most common site of herniation (usually Left side) Other sites = foramen of Morgagni and around the esophagus The view of the diaphragm is from the abdomen looking up towards the thorax

List 2 conditions commonly associated with Kussmaul's sign

Constrictive pericarditis Pericardial tamponade

List 2 conditions commonly associated with pulsus paradoxus

Constrictive pericarditis Pericardial tamponade

How does succinylcholine affect intragastric pressure?

Contraction of the abdominal muscles increases intragastric pressure. At the same time, lowers LES tone. These processes cancel each other out, so the barrier pressure at the GE junction is unchanged Risk of aspiration is not increased

What factors contribute to the spread of LA in the subarachnoid space?

Controllable: Baricity of LA Injection site Dose Positioning Non-controllable- Volume of CSF Density of CSF

What is the most common eye complication in the perioperative period? What is the most common cause of vision loss?

Corneal abrasion is the most common eye complication Ischemic optic neuropathy is the most common cause of vision loss

What is the equation for coronary perfusion pressure?

Coronary perfusion pressure = AoDBP-LVEDP -AoDBP is the pushing force -LVEDP is the resistance to the pushing force -CPP can be improved by increasing AoDBP or decreasing LVEDP (PAOP)

What is the medical treatment for *SLE*? Which drug can affect Succinylcholine metabolism?

Corticosteroids NSAIDs Immunosuppressants *Cyclophosphamide*: may inhibit plasma cholinesterase, inc. DOA succ Azathioprine Methotrexate Myocephenolate motefil

How can you tell the difference between the chemical structures of the halogenated agents?

Count the halogens -Iso has 5 Fl + 1 chlorine -Des has 6 Fl -Sevo has 7 Fl

What is the key function of the descending Loop of Henle?

Countercurrent mechanism High permeability to H2O "D" in descending is for dehydrated = reabsorbs water

What is the key function of the ascending Loop of Henle?

Countercurrent mechanism concentrates urine No permeability to H2O "A" in ascending is for all other = reabsorbs all other solutes

What is the origin of the efferent PNS pathway?

Craniosacral- CN 3, 7, 9, 10 S2-S4 Preganglionic fibers synapse with postganglionic fibers near or in each effector organ ( precise control of each organ)

What are the 3 different types of epidural needles? How are they different from each other?

Crawford = 0 degrees Hustead = 15 degrees. Hustead is fiftean Tuohy = 30 degrees Tuohy = Thirty

Describe the Crawford classification system of aortic aneurysms.

Crawford discusses strictly Thoracic and abdominal Aneurysms Type 1- all or most of descending thoracic aorta, upper portion of abdominal aorta Type 2- all or most of descending thoracic aorta, most of abdominal aorta Type 3- Lower portion of descending thoracic aorta, most of abdominal aorta Type 4- none of descending thoracic aorta, most of abdominal aorta

When is NPA contraindicated?

Cribiform plate injury LeFort 2 or 3 fracture Basilar skull fracture Raccoon eyes CSF rhinorrhea Periorbital edema Coagulopathy Previous transphenoidal hypophysectomy Previous Caldwell-Luc procedure Nasal FX **Caution during pregnancy d/t risk of epistaxis**

Which muscles tense and relax the vocal cords?

CricoThyroid- Cords Tense ThyroaRytenoid- They Relax

Aside from desmopressin, list 3 other treatments that can improve the coagulopathy of Von Willebrand disease?

Cryoprecipitate contains factors 8, 13, fibrinogen and vWF. Can be used for type 1, 2, or 3 disease FFP contains all the clotting factors- can be used for type 1, 2, or 3 disease Purified VIII-vWF concentrate reduces the risk of transfusion related infection. It is the first line agent for patients with type 3 disease

What ratio should be used to replace blood loss with crystalloid, colloid, and blood?

Crystalloid at 3:1 ratio Colloid at 1:1 ratio Blood at 1:1 ratio

What are the 2 classifications of spinal needles?

Cutting tip and non-cutting tip

What are calcineurin inhibitors, and how do they affect renal function?

Cyclosporine and tacrolimus are immunosuppressant agents used to prevent rejection of transplanted organs. SE- HTN and renal vasoconstriction.

Name 6 models of *variable bypass vaporizers*

Datex-Ohmeda Tec 4 Datex-Ohmeda Tec 5 Datex-Ohmeda 7ADU Aladin Drager Vapor 19 Drager Vapor 2000

Name 2 models of *injector (desflurane) vaporizers*

Datex-Ohmeda Tec 6 Drager D-Vapor

What is the most common cause of CKD?

DM

What are examples of hypotonic solutions?

D5W NaCl 0.45%

Location and function of dopamine receptors

DA1 are present in the kidney and splanchnic circulation DA2 are present on the presynaptic adrenergic nerve terminal

What are the *10 steps* in the *treatment of MH*?

DHHD CCC PUD 1. Discontinue triggering agent 2. HELP!!! 3. Hyperventilate w/ 100% FiO2 @ 10L/min 4. Dantrolene 2.5mg/kg q 5-10 min. Continue @ 1mg/kg in ICU. Stop when s/s of hypermetabolism subside 5. Cool the patient to 38degC 6. Correct Lactic Acidosis (sodium bicarb 1-2mEq/kg IV titrated to ABG) 7. Correct/treat Hyperkalemia (CaCl 5-10mg/kg IV + insulin 0.15u/kg + D50 1mL/kg) 8. Protect against Dysrhythmias (Procainamide 15mg/kg) 9. UOP > 2mL/kg/hr (IVF, mannitol 0.25g/kg, furosemide 1mg/kg) 10. Check DIC panel

What are the 2 major classes of CCB?

DHP- nifedipine, nicardipine, nimodipine, amlodipine Non-DHP- verapamil = phenylalkylamine diltiazem- benzothiazepine

What endocrine disorder can occur after transsphenoidal resection of pituitary gland?

DI- usually transient

What is Somatostatin? Where is it released? What does it do?

DIGS Delta cells release it Inhibits Insulin & Glucagon Growth hormone- Inhibiting hormone, regulates endocrine hormone output from the islet cells Splanchnic blood flow, Gastric motility, and Gallbladder contraction all inhibited by Somatostatin (explains why its used portal hypertension)

How do you determine the fraction of a vapor leaving the vaporizer at a given atmospheric pressure?

Divide the agents vapor pressure by given pressure

What are the short term effects of smoking cessation?

Does NOT reduce the risk of POPC SNS stimulating effects of nicotine dissipate after 20-30 min P50 returns to near normal in 12 hours (improved O2 carrying ability)

The structure and function of the dorsal column with the spinothalamic tract

Dorsal column AKA medial lemniscal system FPP V -Transmits mechanoreceptive sensations: fine touch, proprioception, vibration, and pressure -Capable of 2 point discrimination- high degree of localizing the stimulus - Consists of large, myelinated, rapidly conducting fibers -Transmits sensory information faster than the anterolateral system -more evolved system

Regarding neostigmine, what is the dose, onset, duration, metabolism, and best antimuscainic pairing?

Dose 0.02-0.07 mg/kg Onset 5-15 minutes Duration 45-90 minutes Metabolism- 50% renal/50% hepatic Best paired with glycopyrrolate

Regarding pyridostigmine, what is the dose, onset, duration, metabolism, and best antimuscarinic pairing?

Dose 0.1-0.3mg/kg Onset- 10-20min Duration 60-120min Metabolism 75% renal/25% hepatic Best paired with glyco

Regarding edrophonium, what is the dose, onset, duration, metabolism, and best antimuscarinc pairing?

Dose 0.5-1mg/kg Onset 1-2 minutes Duration 30-60min Metabolism 75% renal/25% hepatic Best paired with atropine

What is the dose for PRBC transfusion in the neonate? How much will this increase Hgb?

Dose 10-15 ml/kg 10ml/kg will raise Hgb by 1-2 g/dL

What is the dose, onset, DOA and clearance mechanism for dexmedetomidine?

Dose = 1mcg/kg over 10 minutes Infusion 0.4-0.7mcg/kg/hr Onset- 10-20 minutes Duration-10-30 minutes after infusion stops Clearance-liver via CYP450

What is the dose, onset, duration, and clearance mechanism for propofol?

Dose- Induction 1.5-2.5 mg/kg Infusion- 25-200mcg/kg/min - Onset 30-60 seconds - Duration 5-10 min - Clearance = Liver (P450 enzymes) + extrahepatic metabolism (lungs)

What drugs increase the risk of EPS in the patient with Parkinson's disease?

Drugs that antagonize dopamine should be avoided. Ex: Reglan Butyrophenones (haldol/droperidol) Phenothiazines (promethazine)

What drugs can be used to augment heart rate in the patient with a heart transplant?

Drugs that directly stimulate the SA node can be used- Epi, isoproterenol, glucagon

List the drugs and conditions that decrease pseudocholinsterase activity

Drugs- Reglan, esmolol, neostigmine, echothiophate, oral contraceptives/estrogen, cyclophosphamide, MAOIs, Nitrogen mustard Conditions- atypical PChE, severe liver disease, chronic renal disease, organophosphate poisoning, burns, neoplasm, advanced age, malnutrition, pregnancy (late stage)

Give the name, location, and function of the 3 fetal shunts

Ductus venosus Function- allows umbilical blood to bypass the liver Location- umbilical vein to IVC Foramen ovale Function- shunts blood from RA to LA to bypass the lungs to perfuse the upper body (heart and brain) Location- RA to LA Ductus arteriosus Function-shunts blood from pulmonary trunk to aorta to perfuse lower body Location- Pulmonary artery to proximal descending artery

When does each fetal shunt close? What is the adult remnant of each?

Ductus venosus- closes with clamping of the umbilical cord. Remnant = ligamentum venosus Foramen ovale- closes within 3 days Remnant = fossa ovalis Ductus arteriosus- closes several weeks after birth Remnant- ligamentum arteriosum

What is the relationship between hyperglycemia and cerebral hypoxia?

During cerebral hypoxia, glucose is converted to lactic acid. Cerebral acidosis destroys brain tissue and is associated with worse outcomes. Monitor serum glucose and treat hyperglycemia with insulin

A 3 kg neonate requires emergency ex-lap for NEC. Her preop hct is 50%. What is the MABL to maintain a hct of 40%?

EBV = 3kg x 80-100 ml = 240-300ml Hct starting = 50 Target = 40 MABL = 48-60 mL

Formula for max allowable blood loss

EBV x (Starting Hgb - target Hgb)/starting Hgb

What stimulates the kidney to release erythropoietin? What does EPO do after it's released? How is does this relate to severe kidney disease

EPO is released in response to inadequate O2 delivery to the kidney. Ex: anemia, reduced intravascular volume, hypoxia (high altitude, cardiac/pulmonary failure) EPO stimulates stem cells in the bone marrow to produce RBC Severe kidney disease = ⬇️ EPO production = chronic anemia

Describe how extracorporeal shock wave lithotripsy breaks up kidney stones

ESWL delivers shock waves in rapid succession that are directed at the stone Because the acoustic impedance of water and human tissue is roughly similar, the shock wave moves through the body until it reaches the body-stone interface. At this point, the energy is released, breaking up the stone, producing smaller stone fragments that are eliminated via the urine. Its important that there is nothing between the energy source and the stone.

Contrast the recommended cuff pressure for ETT vs LMA

ETT < 25 cm H2O LMA < 60 cm H2O

What is the MOA of opioids?

Each opioid receptor is linked to a G protein, and agonism of the receptor instructs the G protein to "turn off" adenylate cyclase. This reduces the intracellular concentration of cAMP (second messenger) which alters ionic currents and reduces neuronal function

How do you perform an epidural blood patch? What is the success rate?

Each patch is associated with a 90% success rate. If the HA doesn't improve after 2 blood patches, other etiologies should be sought. Using sterile technique, 10-20cc of venous blood is withdrawn from the patient, then reintroduced into the epidural space. When the patient senses pressure in her legs, buttocks, or back, the injection is complete.

How does hyperkalemia affect the EKG?

Early = long PR, peaked T wave, short QT Middle- flat P, wide QRS Late- QRS progresses to sine wave then to VF

Which type of fetal decelerations are unremarkable?

Early decelerations do not present a risk of fetal hypoxemia.

How do opioids affect the pupil?

Edinger Westphal nucleus stimulation → PNS stimulation of ciliary ganglion and oculomotor nerve → pupil constriction

Define ED50

Effective dose 50: The dose that produces the expected clinical response in 50% of the population. -A measure of potency

What factors do not affect MAC?

Electrolytes -Hyper or hypokalemia -Hyper or hypomagnesemia Other -Hyper or hypothyroidism -Gender -HTN -PaCO2 - 15-95 mmHg

What are the indications for FFP transfusion in the neonate?

Emergency reversal of warfarin Correction of coagulopathic bleeding with increase PT > 1.5 or increased PTT Correction of coagulopathic bleeding if >1 blood volume has been replaced and coags are not easily obtained. FFP is NOT indicated for expansion of intravascular volume

What are low risk surgical procedures according to cardiac risk?

Endoscopic procedures Cataract surgery Superficial procedures Breast surgery Ambulatory procedures

What is the purpose of the unidirectional valves in the breathing circuit?

Ensure gas moves in one direction If a valve becomes incompetent, the patient will rebreathe exhaled gas

What is the primary risk of neuraxial anesthesia in the anticoagulated patient? How does this complication present?

Epidural hematoma Can cause paralysis- presenting s/s include LE weakness, numbness, low back pain, bowel/bladder dysfunction. Surgical decompression within 8 hours offers the best chance of recovery.

Which neuraxial opioid can reactivate herpes simplex labialis?

Epidural morphine Best explained by cephalad spread to trigeminal nucleus. Usually presents 2-5 days after epidural morphine administration

Contrast the regions affected by epiglottitis and croup. -How do these present on a lateral neck x-ray?

Epiglottitis- affects supraglottic structures. On lateral neck XR shows swollen epiglottis (thumb sign) Croup- affects laryngeal structures. On lateral neck XR shows subglottic narrowing (Steeple sign)

Epiglottitis and Croup: What organisms? What age group? What is the onset? What structures are affected

Epiglottitis: B PIGS 2-6RS Bacterial - Pneumococci - Influenza - Group A strep - Staphylococci 2-6y/o Rapid (<24hrs) Supraglotic structures "thumbs sign" Croup: G2 LV Gradual (24 - 72 hours) <2y/o Laryngeal structures: "Steeple sign" Viral - H. parainfluenzae - RSV - Flu type A and B Bacterial (rare): - Mycoplasma pneumoniae

What drugs counter the hypoglycemic effect of insulin?

Epinephrine Glucagon Cortisol

Discuss the modifications to the ACLS treatment protocol when applied to LAST?

Epinephrine can hinder resuscitation from LAST and also reduces the effectiveness of lipid emulsion tx. If epi is used, should be < 1mcg/kg Amiodarone is the agent of choice for ventricular arrhythmias **Avoid vasopressin, lidocaine and procainamide

5 types of tracheoesophageal fistula, which is the most common?

Esophageal atresia is the most common congenital defect of the esophagus, and most of these children also have a tracheoesophageal fistula. Type C accounts for ~90% of all TEF- in this configuration, the upper esophagus ends in a blind pouch and the lower esophagus communicates with the distal trachea

What clinical situations increase ADH release?

Essentially, anything that causes systemic vasodilation PPHH = ADH -PEEP -Positive-pressure ventilation -Hypotension -Hemorrhage IHA impact arterial blood pressure and venous blood volume.

Contrast the metabolism of ester and amide local anesthetics. -Which local anesthetic participates in both metabolic pathways?

Ester metabolism- pseudocholinesterase Amide metabolism- hepatic carboxylesterase/P450 *Cocaine is an exception, it is an ester that is metabolized by pseudocholinesterase and the liver

How can you use the drug name to determine if it's an ester or amide? List examples from each class

Ester- no "i" before "caine" Ex: benzocaine, cocaine, chloroprocaine, procaine, tetracaine Amide- has an "i" before "caine" Ex: lidocaine, prilocaine, etidocaine, bupivacaine, ropivacaine, mepivacaine

What induction agent is most likely to cause PONV?

Etomidate

What is the relationship between etomidate and seizures?

Etomidate commonly causes myoclonus. This is not associated with increased EEG activity in patients that do not have epilepsy. In patients with seizure disorders, etomidate (or methohexital or alfentanil) increases EEG activity and can be used to help determine the location of seizure foci during cortical mapping.

How do the respiratory muscles function during exhalation?

Exhalation is usually passive, driven by recoil of chest wall Active exhalation is carried out by the abdominal musculature (rectus abdominis, transverse abdominis, internal and external obliques) The internal intercostals serve a secondary role in active exhalation Exhalation becomes an active process with minute ventilation increases or in patients with lung disease such as COPD A forced exhalation is required to cough and clear airway of secretions

You see that the CO2 absorbent has changed from white to purple in color. Does this notify you of desiccation or exhaustion?

Exhaustion

Describe the surgical stress response in patients on chronic steroid therapy

Exogenous steroid supplementation suppresses ACTH release from the anterior pituitary gland. Some patients on chronic steroid therapy won't be able to increase cortisol release in response to perioperative stress

How does adding epinephrine affect the DOA of LA?

Extends the duration Decreases systemic uptake of LA, prolongs block duration, and enhances block quality

What are the risks of using succinylcholine with upregulated extrajunctional receptors?

Extrajunctional receptors are much more sensitive to succinylcholine; they remain open for a longer period of time. This augments the potassium leak and may precipitate life-threatening hyperkalemia

Give examples of extrinsic lung diseases (acute and chronic)

Extrinsic lung disease:- Kyphoscoliosis, Ankylosing Spondylosis, Flail chest, Pneumo, Pregnancy, Pleural effusion, Mediastinal mass Neuromuscular disorders, Kytes An Fights PPP Media Nights

What is the treatment for a "tet spell" that occurs during the perioperative period?

FAP DIK FiO2 100% AVOID Inotropes & excessive airway pressures d/t RVOT obstruction Phenylephrine to augment PVR to SVR ratio Deepen anesthesia & BB with short-acting agent (esmolol) to ⬇️ RVOT Intravascular volume expansion Knee-chest position to mimic squatting

What is the diagnostic criteria for DM?

FART Fasting plasma glucose >126 A1c- >6.5% Random glucose level >200mg Two hour plasma glucose >200

Which regulatory agency created the 1993 Anesthesia MAchine Pre-Use Checkout procedures?

FDA

What are the presenting S/sx of *GBS*?

FF FAMS Flu-like illness precedes paralysis by 1-3 weeks Flaccid paralysis: distal extremities ascends to proximal extremities, trunk, face Facial and pharyngeal weakness = difficulty swallowing Autonomic dysfxn including tachy/bradycardia, HTN/HoTN, diaphoresis/anhidrosis, orthostatic HoTN Muscle weakness = impaired vent Sensory deficits include paresthesias, numbness, pain

How does pregnancy affect the lung volumes and capacities

FRC is reduced as a function of decreased ERV and RV. ERV decreases more than RV. An increased oxygen consumption paired with a decreased FRC hastens the onset of hypoxemia. Failure to reverse hypoxemia results in brain death of the mother and the fetus.

What is the function of each of the anterior pituitary hormones?

FSH = germ cell maturation and ovarian follicle growth (females) LH = testosterone production (males) and ovulation (females) ACTH- adrenal hormone release TSH- thyroid hormone release Prolactin- lactation GH- cell growth

What are the changes in pulmonary mechanics due to restrictive lung disease?

FVC, FEV1, RV, FRC, TLC are all decreased FEV1/FVC ratio and FEF 25-75% are normal, because all other capacities are decreased proportionally

Describe the pathophysiology and treatment of factor V Leiden mutation

Factor V Leiden causes a resistance to the anticoagulant effect of protein C Treatment- only patients with thromboembolism require anticoagulation. Lifelong anticoagulation is unwarranted unless the patient experiences recurrent thrombotic events.

What is another name for the *oxygen pressure failure device*?

Fail-safe device

What conditions increase the risk of failure to capture?

Failure to capture occurs when the myocardium becomes more resistant to depolarization Due to Hyper or Hypokalemia Things that can cause either of these: - Hypocapnia (intracellular K shift. Every 10 mmHg decrease in PaCO2 causes concomitant reduction in serum K+ by approximately 0.5 mmol/L) - Hypothermia - MI - Fibrotic tissue buildup around pacing leads - Antiarrhythmic medications

How do you interpret the fraction excretion of sodium

Fe(Na) relates sodium clearance to creatinine clearance. If Fe(Na) < 1% = suggests prerenal azotemia. If Fe(Na) >3%, = impaired tubular fluid.

What are the risk factors for halothane hepatitis?

Female Age >40 Fat CYP2E1 induction- ETOH, isoniazid, phenobarbital Genetics >2 exposures

What is the P50 of fetal hemoglobin? -Why is this important?

Fetal Hgb has a P50 of 19 mmHg This shifts the curve left It benefits the fetus by creating an oxygen partial pressure gradient across the uteroplacental membrane that facilitates the passage of O2 from the mother to the fetus.

What is in cryoprecipitate?

Fibrinogen Factor 8 Factor 13 vWF

What are the indications for cryoprecipitate transfusion?

Fibrinogen deficiency (<80-100 mg/dl) vWB disease Hemophilia

Describe the organization of the 3 neuron pathway common to the spinal tracts.

First order = connects peripheral nerve to spinal cord or brainstem Second order = links spinal cord/brainstem to a subcortical structure Third order = Links subcortical structure to cerebral cortex

Compare and contrast the pain that results from the first and second stages of labor. Type of pain? Orgin? Transmitted by?

First stage- Pain begins in the lower uterine segment and the cervix. Dull, achy, poorly localized. Origin: T10-L1 posterior nerve roots Transmitted: slow C fibers. Second stage- adds in pain impulses from the vagina, perineum, and pelvic floor. Origin: S2-S4 posterior nerve roots Transmitted: Rapid A delta fibers

A new anesthetic drug is cleared from the body at a rate proportional to its plasma concentration. What kinetic model best describes the elimination of this drug?

First-order kinetics -a constant fraction of drug is eliminated per unit time

Discuss the pathophysiology of flail chest, and treatment options

Flail chest is a consequence of blunt chest trauma with multiple rib fractures. The key characteristic is paradoxical movement of the chest wall at the site of the fractures. Treatment- epidural catheter or intercostal nerve blocks

Regarding hepatic clearance, what is flow-limited elimination?

Flow limited elimination = ER >0.7 -Clearance is dependent on liver blood flow - Hepatic blood flow greatly exceeds enzymatic activity, so alterations in hepatic enzyme activity has little effect -Increase in liver blood flow = increased clearance and vice versa

Pressing the oxygen flush valve exposes the breathing circuit to _____ O2 flow and _____ O2 pressure.

Flow- 35-75L/min Pressure- 50 psi (pipeline)

Anesthetic management for preeclampsia Fluid management? Neuraxial? Airway Response to rx?

Fluid management is balanced between a volume contracted patient and a 'leaky' vasculature from endothelial dysfunction Neuraxial anesthesia assists with BP control and also provides better uteroplacental perfusion. Be sure to r/o thrombocytopenia before performing a neuraxial block. Airway swelling = higher incidence of difficult intubation Response to Rx: Exaggerated response to sympathomimetics and methergine If on mag, increased sensitivity to NMB. Mag relaxes the uterus and increases the risk of postpartum hemorrhage

What is lymph and how does the lymphatic system work?

Fluid scavenger- removes fluid, protein, bacteria, and debris that has entered the interstitium. It accomplishes this goal with a pumping mechanism that propels lymph through a vessel network lined with one-way valves. This creates a net-negative pressure in the interstitial space. Edema occurs when the lymphatic system is unable to do its job.

In what circumstances can thiopental be used for neuroprotection?

Focal ischemia- CEA, temporary occlusion of cerebral arteries No neuroprotection for global ischemia (cardiac arrest)

For every ___mmHg increase/decrease in PaCO2 CBF will increase/decrease by how much? At what PaCO2 does maximal cerebral vasodilation occur? How about maximal cerebral vasoconstriction?

For every 1 mmHg increase (or decrease) in PaCO2, CBF will increase (or decrease) by 1-2 ml/200g/min Max vasodilation occurs at PaCO2 of 80-100mmHg Max vasoconstriction occurs at a PaCO2 of 25 mmHg

Where are PLT formed? Where are they metabolized?

Formed by megakaryocytes in the bone marrow Cleared by macrophages in the reticuloendothelial system and the spleen

List 1 drug that is biotransformed by alkaline phosphatase hydrolysis?

Fospropofol

List the name of function of the 4 lobes of the cerebral cortex

Frontal- contains the motor cortex Parietal- contains somatic sensory cortex Occipital- contains visual cortex Temporal- contains auditory cortex and speech centers Wernicke's area = understanding speech Broca's area = motor control of speech

What is Pancreatic Polypeptide?

GIG Gallbladder contraction, and gastric motility inhibited (like Somatostatin) Inhibits Pancreatic Exocrine hormone secretion Gastric acid secretion inhibited (unlike Somatostatin) Secreted by PP cells on pancreas

A *Right to Left shunt* occurs when PVR is ____________ than SVR. (greater/less than?)

GREATER PVR > SVR = R to L shunt

List 3 safety relief devices that prevent a cylinder from exploding when the ambient temperature increases.

Gas cylinders should never be exposed to temperatures higher than 130 F- temperatures higher than this may lead to a fire or explosion Safety relief devices include: -Fusible plug made of Wood's metal -Frangible disk that ruptures under pressure -Valve that opens at elevated pressures

Anesthetic management for patient with omphalocele or gastroschisis

Gastroschisis = SSC MEN Schisis in a bag! (minimize water/heat loss) Surgical closure may require staging if >25-30 cmH2O then Closure may increase IAP = decreased venous return/CO= decreased systemic perfusion. Measure SpO2 on LE to monitor for increased IAP Electrolyte/fluid shifts N2O distends bowel and may impair surgical closure

What is the risk of perioperative myocardial infarction in the patient with a previous MI?

General population- 0.3% MI if > 6 months = 6% MI if 3-6 months = 15% MI < 3 months = 30% -The highest risk of reinfarction is greatest within 30 days of an acute MI. For this reason, the ACC/AHA guidelines recommend a minimum of 4-6 weeks before considering elective surgery in a patient with a recent MI.

How does the kidney eliminate toxins and metabolites?

Glomerular filtration and tubular secretion clear the blood of metabolic byproducts, toxins and drugs Like the liver, the kidney is capable of phase 1 and 2 biotransformation

What are the 3 determinants of glomerular hydrostatic pressure?

Glomerular hydrostatic pressure is the most important determinant of GFR. 3 determinants Arterial blood pressure Afferent arteriole resistance Efferent arteriole resistance

A patient presents for removal of a glomus tumor. What are your primary concerns when planning your anesthetic?

Glomus tumors originate from neural crest cells. They tend to grow in neuroendocrine tissues that lay in close proximity to the carotid artery, aorta, glossopharyngeal nerve, and middle ear. -They can release several vasoactive substances that can lead to exaggerated hyper or hypotension (NE, 5-HT, bradykinin, histamine) -CN dysfunction can cause swallowing impairment, aspiration or airway obstruction Surgical dissection of a glomus tumor that has invaded the IJ increases risk of VAE

Name 3 airway blocks and identify key landmarks for each one

Glossopharyngeal- palatoglossal arch at the anterior tonsillar pillar SLN block- at the greater cornu of the hyoid Transtracheal nerve block- cricothyroid membrane

What drugs can be used to relax the sphincter of Oddi?

Glucagon Narcan NTG Glycopyrrolate and atropine may help as well

How does dextrose affect the tonicity of IVF?

Glucose is metabolized to carbon dioxide and water = Water is hypotonic

How can acetaminophen cause hepatic injury? -What is the treatment?

Glutathione is a substrate for many phase 2 conjugation reactions. It increases a substances' water solubility, so the substance can be excreted in the bile or by the kidney. APAP produces a toxic metabolite called n-acetyl-p-benzoquinoneimine (NAPQI) With normal APAP dosing, NAPQI is conjugated with glutathione. The conjugated metabolite is not toxic. APAP OD consumes the liver's supply of glutathione Since the conjugation substrate isn't available, the concentration of NAPQI rises, and leads to hepatocellular injury. Treatment = Mucomyst within 8 hours of OD

What is the risk of glycine when used for irrigation during TURP?

Glycine metabolism can increase Ammonia production= Encephalopathy. Glycine is an inhibitory neurotransmitter in the retina = Transient blindness or blurry vision for up to 24-48 hours

List the 4 types of oropharyngeal airways. Which are best suited for FOB intubation?

Guedel Berman Williams Ovassapian Williams/ovassapian are best for FOB intubation

List the s/s of intracranial HTN

HA N/V Papilledema (swelling of optic nerve) Focal neurologic deficit Decreased LOC Seizure Coma

What drugs should be avoided in the patient with acute intermittent porphyria? Why?

HA BEG Hydralazine Avoid emotional stress and prolonged NPO status Barbiturates Etomidate Glucocorticoids

Which drugs should be avoided in the patient with hepatitis?

HAAA Halothane Acetamenophen Amiodarone ABX- PCN, tetracycline, sulfonamides

Describe the physiologic changes that occur as a result of massive transfusion.

HAHAHH Hypothermia from transfusion of cold blood Alkalosis from citrate metabolism to bicarb in the liver Hyperglycemia from dextrose added to stored blood Acidosis from inadequate oxygenation and increased serum lactate Hypocalcemia from binding of calcium by citrate Hyperkalemia from administration of older blood.

What are the *hematologic complications* of *SLE*?

HALT A Hypercoagulability Anemia Leukopenia Thrombocytopenia Antiphospholipid antibodies

Describe aspiration prophylaxis for the patient scheduled for a cesarean section.

Triple prophylaxis -Sodium citrate -H2 antagonist- Ranitidine -Gastrokinetic agent- Reglan

How should you induce anesthesia in a patient undergoing a type C TEF repair?

HAP GEAR Head up with frequent suction to minimize the risk of gastric aspiration Awake intubation or inhalation induction with spontaneous ventilation PPV = gastric distension = decreased thoracic compliance = increased PIP to ventilate- vicious cycle G tube allows for gastric decompression. If pt already has a G tube, open to atmosphere before induction. ETT below the fistula, but above the carina A precordial stethoscope placed on the left chest will immediately detect a right mainstem intubation Right lung compression during a surgical repair is common. Right mainstem will cause rapid desaturation.

Possible causes of non-gap acidosis

HARDUP Hypoaldosteronism Acetazolamide Renal tubular acidosis Diarrhea Ureterosigmoid fistula Pancreatic fistula Large volume resuscitation with NaCL= non gap metabolic acidosis with hyperchloremia

Describe the pulmonary changes that accompany cirrhosis

HARP Hepatopulmonary syndrome- pulmonary vasodilation = intrapulmonary shunt = hypoxemia Alkalosis- hypoxemia = compensatory hyperventilation Restrictive defect- ascites and/or pulmonary effusion reduces pulmonary compliance Portopulmonary HTN = PAP >25 in the setting of portal HTN

What are the s/sx of methemoglobinemia?

HAT CCT Hypoxia AMS Tachycardia Cyanosis Chocolate colored blood Coma or death Tachypnea

What is the treatment for acute adrenal crisis?

HEH Hydrocortisone 100 mg + 100-200 mg q24h ECF volume expansion (D5NS is best) Hemodynamic support

What factors reduce ventricular compliance?

HIPPA Hypertropic obstructive cardiomyopathy Ischemia Pericardial pressure Pressure overload hypertrophy Age > 60 years *Higher filling pressures are required to prime the ventricle

What are the immunologic effects of opioids?

HIS -Histamine release -Inhibition of cellular and humoral immune function -Suppression of natural Killer cell function

How and when does pyloric stenosis present?

HONO Hypertrophy of the pyloric muscle creates a mechanical obstruction at the gastric outlet (between the stomach and duodenum) Olive shaped mass can be palpated just below the xiphoid process Non-bilious projectile vomiting Occurs in the first 2-12 weeks of life, more common in males

What are glucocorticoid effects?

HOW I M&M -Hyperglycemia -Osteoporosis -Weight gain -Infection -Muscle weakness -Mood disorder

How do heart rate and stroke volume and cardiac output change in the elderly?

HR, SV, CO all decrease

How do opioids affect HR, BP, and myocardial function?

HR- bradycardia d/t Mu stimulation (Mu-2). Meperidine can increase HR d/t atropine-like ring in chemical structure which produces anticholinergic effects: tachycardia, mydriasis, dry mouth BP- minimal, may have some hypotension with histamine releasing opioids Myocardial function- contractility unaffected, can have myocardial depression if combined with N2O

What is the second most common cause of CKD?

HTN

What is Cushing's triad? What is the clinical relevance of this reflex?

HTN/Bradycardia/irregular respirations Increased ICP decreases CPP. In an effort to improve the CPP, BP increases. HTN activates the BRR leading to bradycardia. Compression of the medulla causes irregular respirations.

What process determines the intrinsic heart rate, and what physiologic factors alter it?

Heart rate is determined by the rate of spontaneous phase 4 depolarization in the SA node -We can increase HR by manipulating 3 variables -The rate of spontaneous phase 4 depolarization increases (reaches TP faster) -TP becomes more negative (shorter distance between RMP and TP) -RMP becomes less negative (Shorter distance between RMP and TP) -When RMP/TP are close = easier for cell to depolarize -When RMP/TP are far = harder for cell to depolarize

What is the primary determinant of blood pressure in the neonate?

Heart rate is the primary determinant of cardiac output and SBP. BP = HR x SV x SVR The neonatal myocardium lacks the contractile elements to significantly adjust contractility or SV; the ventricle is noncompliant. Furthermore, the Frank-Starling relationship is underdeveloped in the newborn. Therefore, HR must be maintained to ensure adequate tissue perfusion and oxygen delivery.

What are the hemodynamic goals for mitral stenosis?

Heart rate- slow normal Avoid increase in peripheral vascular resistance

What are the hemodynamic goals for aortic stenosis?

Heart rate- slow normal Increase preload Increase or normal SVR

Calculate IBW for female

Height in cm - 105

Describe the Cormack and Lehanne score

Helps measure the view obtained during DL. Grade 1- full view, can see anterior/posterior commisure Grade 2-Cannot see anterior commisure Grade 3- can only see epiglottis, no glottic opening Grade 4- can't see anything

What is HELLP syndrome? What is the definitive treatment?

Hemolysis, elevated liver enzymes, low PLT count. Develops in 5-10% of patients with preeclampsia. These patients experience epigastric pain and upper abdominal tenderness. Treatment for HELLP = Help DELIVER the BABY

What are the potential complications of mediastinoscopy? What is the most common?

Hemorrhage (most common) Pneumothorax (second most common) Impaired cerebral perfusion Dysrhythmias Air embolism Chylothorax Hoarseness/VC paralysis

What are the doses of heparin for CPB and protamine?

Heparin - 300-400 u/kg Protamine dose- 1mg for every 100U of heparin predicted to be in circulation

What is the MOA of heparin?

Heparin inhibits the intrinsic and final common pathways Antithrombin III is a naturally occuring anticoagulant that circulates in the plasma. Heparin binds to AT and greatly accelerates its anticoagulant activity. The heparin-AT complex neutralizes thrombin and activated factors X, XII, XI, and IX

What is the hepatic arterial buffer response?

Hepatic Arterial Perfusion Pressure = MAP - Hepatic Venous Pressure Hepatic arterial buffer response: A reduction in Portal Vein flow is compensated by an increase in Hepatic Arterial flow ➡️Mediated by Adenosine 🚫Severe Liver Disease impairs this response

What are the best tests of Hepatic synthetic function? Which is best for Acute Injury? Why?

Hepatic synthetic function: PT. Normal 10.9-12.5 seconds Acute injury: Factor 5 and 7 (T1/2 i= 3-6 hours). Albumin (normal 3.5-5) not sensitive for acute injury(T1/2 = 21 days)

Which reflex prevents overinflation of the lungs?

Hering-Breuer inflation reflex

What factors increase compound A production with sevoflurane?

High concentrations over a long period of time Low FGF High temperature CO2 absorbent Increased CO2 production

What is the risk of neuraxial anesthesia in the patient with coagulopathy? What lab values are considered contraindications to a neuraxial technique?

Higher risk of spinal or epidural hematoma Neuraxial blocks are contraindicated in significant pathologic or therapeutic coagulopathic states. PLT <100,000 PT, aPTT, and/or bleeding time 2x the normal value

Discuss the presentation, risks, and treatment of hypoglycemia in the perioperative period?

Highest risk if insulin given during fasting s/s-SNS stimulation Difficult to dx under GA Possible cause of delayed emergence Rebound hyperglycemia (Somogyi effect) may cloud diagnosis Tx- D50 (50-100ml) or glucagon (0.5-1 mg) IV or SQ

What drugs should be avoided in the patient with carcinoid syndrome?

Histamine releasing drugs Succs- fasciculations can increase hormone release from the tumor Exogenous catecholamines Sympathomimetic agents- ephedrine/ketamine

How does CKD affect the serum potassium? How is hyperkalemia treated in this patient population?

HyperK d/t impaired potassium excretion Dialysis is indicated when serum K is > 6mEq/L Other tx: Glucose + insulin Hyperventilation NaHCO3 CaCL

What conditions increase the risk of CNS toxicity from LAST?

Hypercarbia- increases CBP = increased drug delivery to the brain. Also decreases protein binding = increased free fraction Hyperkalemia- raises RMP making neurons more likely to depolarize Metabolic acidosis- decreases the convulsion threshold and favors ion trapping inside the brain

Why is calcium used to treat hyperkalemic cardiac arrest caused by succinylcholine?

Hyperkalemia raises RMP, so excitable tissues are closer to TP and depolarization Administration of IV calcium increases the TP, which helps re-establish the normal difference between TMP

What are the two most significant risks associated with sugammadex?

Hypersensitivity In the event that additional surgery is required shortly after sugammadex administration, there is a concern about the ability to re-paralyze the patient with an aminosteroid NMB -In this situation, a larger dose of rocuronium may be required - Roc will have a longer onset and shorter DOA -Makes more sense to use a benzylisoquinolinium compound

When is it ok for a patient with hyperthyroidism to undergo surgery? -What about a hypothyroid patient?

Hyperthyroid- do NOT proceed with elective surgery until the patient is euthyroid. Successful medical management may require up to 6-8 weeks. Emergency surgery warrants administration of a BB, potassium iodide, glucocorticoid, and PTU Hypothyroid- ok to proceed to surgery if mild to moderate disease

How are TSH, T3, and T4 levels affected by hyper and hypothyroidism?

Hyperthyroidism = low TSH + High levels of T3 and T4 Hypothyroidism = High TSH + Low T3 and T4

What are 2 common ways of reducing ICP that should specifically be avoided in the patient with a TBI?

Hyperventilation can worsen cerebral ischemia in patients with TBI. Steroids worsen neurologic outcome.

Misc. effect of alkalosis

Hypokalemia Decreased ionized calcium

What is the risk of distilled water when used for irrigation for TURP?

Hyponatremia, hypo-osmolality, hemolysis and hemoglobinuria

What is the most common complication of dialysis

Hypotension

What are the SE of protamine?

Hypotension - d/t histamine release, give over 5 minutes Pulmonary HTN- TxA2 and serotonin release Allergic reaction- previous sensitization to NPH insulin Fish allergy

What is the relationship between the tonicity of IV solutions and increased ICP?

Hypotonic solutions have a lower osmolarity than the plasma. These fluids are the same as giving free water, and this free water distributes throughout all the body compartments. This is why hypotonic solutions are poor expanders of intravascular volume, and also why you should never give a hypotonic solution to a patient with an increased ICP. It will cause the cells to swell, increase their volume, and increase ICP. Hypertonic solutions are useful for treating cerebral edema (pulls water out of cells causing them to shrink)

Factors that increase pulmonary vascular resistance

Hypoxemia, hypercarbia, acidosis, SNS stimulation, pain, hypothermia Increased intrathoracic pressure- PEEP, atelectasis, mechanical ventilation Drugs- N2O, ketamine, desflurane

What is HPV?

Hypoxic pulmonary vasoconstriction minimizes shunt by reducing blood flow through poorly ventilated alveoli (atelectasis or OLV) A low alveolar PO2 is the trigger that activates HPV. The effect begins almost immediately and reaches full effect after 15 minutes

Cobb angle ranges

I PP Gas Indication for surgery Pulm reserve decrease Pulm symptoms present Gas exchange impaired + POPC

What is the normal ICP? What values are considered abnormal?

ICP is the supratentorial CSF pressure. Normal is 5-15 mmHg HTN occurs if ICP >20 mmHg

When is ICP measurement indicated? -What is the gold standard for measurement?

ICP measurement is indicated with a GCS <7 An intraventricular catheter is the gold standard for ICP measurement. ICP can also be measured with a subdural bolt or a catheter placed over the convexity of the cerebral cortex.

List the absolute indications to one-lung ventilation.

ICU Isolation of one lung to avoid contamination- infection or massive hemorrhage Control of distribution of ventilation- BP fistula, Surgery on Major airway, Uilateral lung cyst or bulla, Life threatening hypoxemia r/t lung disease Unilateral bronchopulmonary lavage- pulmonary alveolar proteinosis

What factors are in the extrinsic pathway?

III, VII Extrinsic pathway can be purchased for 37 cents

Describe the pathophysiology of ischemic optic neuropathy

ION is a consequence of ischemia of the optic nerve. The most likely explanation is that venous congestion in the optic canal reduces perfusion pressure. Increased IAP and/or intrathoracic pressure can also increase IOP The central retinal and posterior ciliary arteries are at highest risk because they are "watershed" areas - they lack anastomoses with other arteries. A rise in IOP can compress these vessels, which reduces O2 delivery to the retina.

Define the 5 lung volumes and give reference values for each

IRV- 3L- Amount of gas that can be forcibly inhaled after tidal inhalation TV- 500mL- ERV 1.1L- amount of gas that can be forcibly exhaled after tidal expiration RV 1.2L- volume remaining after complete expiration Closing volume- variable- volume above RV where small airways begin to close

What are the IV and PO doses for midazolam? -Why are they different?

IV sedation = 0.01-0.1mg/kg IV induction- 0.1-0.4mg/kg PO sedation in kids 0.5-1mg/kg PO bioavailability = 50% d/t significant first pass metabolism

What are the potential routes of administration for ketamine? Doses for each route?

IV- Induction 1-2mg/kg Analgesia- 0.1-0.5mg/kg IM-4-8mg/kg PO-10mg/kg

What are the implications when a drug's VD exceeds TBW?

If VD>TBW the drug is assumed to be lipophilic. It distributes into TBW + fat, and will require a higher dose to achieve a given plasma concentration Ex: propofol, fentanyl

How is *Hypokalemic* periodic paralysis diagnosed?

If skeletal muscle weakness follows glucose-insulin infusion (serum K reduced), then pt has HYPOkalemic PP .

How is *Hyperkalemic* periodic paralysis diagnosed?

If skeletal muscle weakness follows oral K administration(serum K increased), then pt has HYPERkalemic PP .

Under what circumstances are abx indicated for a patient with either VSD or ASD?

If surgical repair of defect is < 6 months old

How does atrial pacing affect the QRS complex? How about ventricular pacing?

If the atrium is paced, the electrical signal travels through the AV node and the QRS maintains its normal, narrow appearance. If the ventricle is paced, the electrical signal is delivered beyond the AV node, and the QRS takes on a wide appearance.

Describe the myogenic mechanism of renal autoregulation

If the renal artery pressure is elevated, the myogenic mechanism constricts the afferent arteriole to protect the glomerulus from excessive pressures. When the renal artery pressure is too low, the myogenic mechanism dilates the afferent arteriole to increase blood flow going to the nephron

Pathophysiology of neurogenic shock

Impairment of cardioaccelerator fibers (T1-T4) = unopposed cardiac vagal tone = bradycardia and reduced inotropy Decreased SNS tone = vasodilation-venous pooling = decreased CO and BP Impairment of SNS pathways to blood vessels = inability to vasoconstrict or shiver- hypothermia

Discuss the respiratory effects of neuraxial anesthesia

In healthy patients = negligible effects Accessory muscle function is reduced. Impairment of the intercostal muscles (inspiration and expiration) as well as the abdominal muscles (inability to cough and clear secretions) will decrease pulmonary reserve. This is particularly important for patients with severe COPD. Apnea is usually the result of cerebral hypoperfusion NOT phrenic nerve paralysis or high concentrations of LA in the CSF

How and where is EPI synthesized?

In the adrenal medulla, NE (phenylethanolamine-N-methyltransferase) to Epi

How do you block the median nerve at the forearm?

In the antecubital fossa, LA is injected medial to the brachial artery Volume 3-5 ml Avoid this block in the patient with carpel tunnel syndrome

Describe the pathophysiology of Parkinson's disease

In the patient with Parkinson's disease, the dopaminergic neurons in the basal ganglia are destroyed. Decreased dopamine + normal acetylcholine = relative acetylcholine increase = suppression of corticospinal motor system + overactivity of extrapyramidal motor system.

Which inhalation anesthetics are most greatly affected by a right-to-left shunt?

In the presence of a right-to-left shunt, the FA/FI of an agent with lower solubility (Des) will be more affected than an agent with higher solubility (Iso)

Who is at risk for aortocaval compression, and how do you treat it?

In the supine position, the gravid uterus compresses both the vena cava and the aorta. This decreases venous return to the heart as well as the arterial flow to the uterus and LE. Decreased CO compromises fetal perfusion and can also cause the mother to lose consciousness. By displacing the uterus away from the vena cava and aorta, we can reduce its compressive effect. We can accomplish this by elevating the mother's right torso 15 degrees. It should be used for anyone in their second or third trimester.

What happens when you accidently inject LA into the subdural space during a SAB? How about during an epidural?

Inadvertent injection of LA into the subdural space will yield the following outcomes Epidural - high spinal with delayed onset (15-20min) Spinal dose = failed spinal

What are examples of rebreathing?

Incompetent one-way valve Exhausted soda lime

The sodalime becomes exhausted mid-procedure. What is the best action to take at this time?

Increase FGF to convert the circle system to a semi-open system

WHat are the hemodynamic goals for aortic insufficiency?

Increase HR Increase preload Decrease SVR

What are the hemodynamic goals for mitral insufficiency?

Increase HR Increase preload decrease SVR avoid increases in PVR

What are the hemodynamic goals for tetralogy of Fallot?

Increase SVR Increase preload Decrease PVR Maintain contractility

You notice that the soda lime has become exhausted in the middle of a surgical procedure. What is the best action to take at this time?

Increase the FGF to 3x the patient's MV

What is the MOA of sugammadex?

Sugammadex is a gamma-cyclodextrin made of 8 sugars assembled in a ring. The rink encapsulates the NMB, rendering it inactive and unable to engage with the nicotinic receptor.

What factors increase or decrease the CVP?

Increase- transducer below the phlebostatic axis, hypervolemia, RV failure, Tricuspid stenosis or regurg, pulmonic stenosis, pulmonary HTN, PEEP, VSD, constrictive pericarditis, cardiac tamponade Decrease- transducer above the phlebostatic axis, hypovolemia

Causes of increased ETCO2 that occur d/t changes in CO2 production

Increased BMR MH Thyrotoxicosis Fever Sepsis Seizures Laparoscopy Tourniquet or vascular clamp removal NaHCO3 administration Anxiety Pain Shivering Increased muscle tone (occurs after NMB reversal) Medication SE

CNS effects of acidosis

Increased CBF Increased ICP

What hemodynamic conditions reduce the CO in the patient with hypertrophic cardiomyopathy?

Increased HR (tx with BB/CCB) Increased contractility Decreased preload (IVF) Decreased afterload (Neo)

Cardiac effects of acidosis

Increased P50 Decreased contractility Increased SNS tone Increased risk of dysrhythmias

What lab results are consistent with DIC?

Increased PT, PTT, and D-Dimer Decreased PLT and fibrinogen

What lab results are consistent with Von Willebrand disease?

Increased PTT Increased bleeding time

Factors that decrease pulmonary vascular resistance

Increased PaO2, hypocarbia, alkalosis Decreased intrathoracic pressure- Prevent coughing/straining, normal lung volumes, spontaneous ventilation, HFJV Drugs-inhaled nitric oxide, NTG, PDE-I (sildenafil), Prostaglandins, CCB, ACE-I

Causes of decreased ETCO2 due to changes in alveolar ventilation or equipment malfunction

Increased VA- hyperventilation, inadequate anesthesia, metabolic acidosis, Rx SE Equipment- vent d/c, esophageal intubation, poor seal with ETT/LMA, sample line leak, airway obstruction, apnea

A patient is receiving PCV. What conditions can *increase* the tidal volume delivered to the patient?

Increased compliance - release of pneumo - going from t-berg to supine Decreased resistance - bronchodilator therapy - removing airway secretions

What electrolyte disturbances can potentiate the effects of NMB?

Increased lithium and mag Decreased calcium and potassium

Pulmonary effects of acidosis

Increased pulmonary vascular resistance

*MG* patients will have ____________ sensitivity to non-depolarizing NMBs.

Increased sensitivity - reduction in # of receptors at NMJ means they are saturated faster

What factors cause a right shift in the oxyhemoglobin dissociation curve?

Increased temp, increased 2-3 DPG, increased CO2, Increased H+, decreased pH

How does minute ventilation change in the elderly?

Increases Increased dead space necessitates an increased minute ventilation to maintain a normal PaCO2

How does thyroid hormone affect the respiratory system?

Increases BMR = increased O2 consumption = Increased CO2 production = Increased Vte

5 indications for use of a bronchial blocker

Indicated for lung separation in patients who: are children < 8 years old Require nasal intubation Have a tracheostomy Have a single lumen ETT in place Require intubation post-op and want to avoid changing a DLT for single-lumen ETT at end of case

What types of surgical procedures are well suited for an interscalene block? Which are not?

Indicated for procedures involving the shoulder and proximal upper extremity. Not the best option for procedures below the level of the elbow- frequently spares roots C8-T1. This region innervates portions of the forearm and hand.

What tests can measure FRC?

Indirect measurement via nitrogen washout, helium wash-in or body plethysmography

How do brain waves change during general anesthesia?

Induction or light anesthesia = increased beta wave activity Theta and delta waves predominate during GA Deep anesthesia = burst suppression At 1.5-2 MAC, GA cause complete suppression or isoelectricity

What is the most common congenital cardiac anomaly in infants and children? How about adults?

Infants/kids- VSD (closes by age 2) Adults- bicuspid aortic valve

What is the dose for IM succs? Which IM site has the fastest onset?

Infants/neonates = 5mg/kg Older children = 4mg/kg Intralingual administration via the submental approach has the fastest onset

List 7 patient factors that warrant antibiotic prophylaxis against infective endocarditis

Infective endocarditis Prosthetic heart valve Unrepaired cyanotic CHD Repaired CHD if < 6 months old Repaired CHD with residual effects that have impaired endotheliazation at the graft site Heart transplant with valvuloplasty

What is the role of inflammation in pain transduction?

Inflammation contributes to reduced threshold to pain stimulus (allodynia) Increased response to pain (hyperalgesia)

What types of surgical procedures are well suited for an infraclavicular block?

Infraclavicular = cord level Covers the upper extemity below the elbow Shoulder/upper arm not anesthetized

How do intracardiac (Acyanotic & Cyanotic) shunts affect an inhalation or IV induction?

Inhalation induction R-L shunt = slower induction L-R shunt = minimal effect IV induction R-L shunt = faster induction L-R shunt = slower induction (potentially)

How are inhalation anesthetics removed from the body?

Inhaled anesthetics are eliminated from the body in 3 ways -elimination from alveoli -hepatic biotransformation -percutaneous loss -

MOA of warfarin

Inhibits the enzyme vitamin K epoxide reductase complex 1, which is responsible for converting inactive vitamin K to active vitamin K Indirectly blocks the manufacture of the vitamin K dependent factors- 2, 7, 9, 10 and protein C&S

What is the initial elevation, peak elevation and return to baseline for CK-MB?

Initial elevation within 3-12 hours Peak elevation at 24 hours Returns to baseline within 2-3 days

What is the initial elevation, peak elevation and return to baseline for Troponin I?

Initial elevation- 3-12 hours Peak elevation at 24 hours Returns to baseline in 5-10 days

What is the initial elevation, peak elevation, and return to baseline for Troponin T?

Initial elevation- 3-12 hours Peak in 12-48 hours Return to baseline in 5-14 days

How does pregnancy affect the mother's abg?

Initially mom's PaCO2 falls = respiratory alkalosis. However, Renal compensation eliminates bicarbonate to normalize blood pH. A small reduction in physiologic shunt explains the mild increase in PaO2. This increases the driving pressure of oxygen across the feoplacental interface and improves fetal gas exchange. Arterial pH = no change PaO2 = Increased (104-108) PaCO2 = Decreased (28-32) HCO3 = Decreased (20)

What are the 3 phases of the contemporary cell-based coagulation cascade?

Initiation Amplification Propagation

Discuss the process of pain transduction

Injured tissues release a variety of chemicals that activated peripheral nerves and/or cause immune cells to release pro inflammatory compounds. The peripheral nerves traduce this chemical soup into an action potential so the extent of tissue injury can be interpreted by the brain

Discuss the anatomy of the renal medulla

Inner part of kidney Contains the parts of the nephron not in the renal cortex (loops of Henle and collecting ducts) Medulla is divided into Pyramids➡️ Papilla ➡️ Minor Calyxes ➡️ Major Calyxes.➡️ Renal pelvis➡️ Ureter➡️ Bladder.

Discuss the association between insulin and allergic reactions

Insulin allergy was more common when animal derived insulin products were used Chronic NPH use (or fish allergy) may sensitize the patient to protamine. This may not manifest until a large dose of protamine is administered (cardiac surgery)

In addition to a brachial plexus block, which nerve must also be anesthetized to foster the tolerance of an upper extremity tourniquet?

Intercostobrachial blockade may faster tolerance for an upper arm tourniquet in an awake patient. Arises from T2 Field block is required to block this nerve.

Describe the superior laryngeal nerve innervation of the airway

Internal branch- posterior side of epiglottis to the level of the VC External- no sensory, provides motor innervation to cricothyroid muscle

Rank injection sites to the corresponding plasma concentrations of local anesthetics.

Interpleural intercostal caudal epidural brachial plexus femoral sciatic sub Q

What is the risk of intra-arterial injection of thiopental? What is the treatment?

Intra-arterial injection = intense vasoconstriction + crystal formation + inflammation = tissue necrosis Tx- Injection of vasodilator (phentolamine or phenoxybenzamine) Sympathectomy- stellate ganglion block or brachial plexus block

What are intermediate risk surgical procedures according to cardiac risk?

Intrathoracic or intraperitoneal surgery CEA Head and neck surgery Orthopeduc surgery Prostate surgery

What lab results are consistent with hemophilia A?

Intrinsic pathway = increased PTT

What is intrinsic renal injury? What is the treatment?

Intrinsic- parenchymal ATN ischemia (medulla at highest risk) or nephrotoxic drugs (IV contrast dye, ABX, NSAIDS) Treatment- Restore renal perfusion, supportive

How does ionization affect solubility, pharmacologic effect, hepatic biotransformation, renal elimination, and diffusion across lipid bilayers?

Ionized = water soluble, not pharmacologically active, more likely to undergo renal elimination, cannot diffuse across BBB, GI tract or placenta Unionized- lipid soluble, pharmacologically active, more likely to undergo hepatic biotransformation, can diffuse across BBB, GI tract and placenta

Describe the autonomic innervation of the pancreas

Islet B cells- A2 = decreased insulin release B2= increased insulin release

How do isotonic IVF distribute in the patient?

Isotonic solutions have an osmolarity that is very close to the plasma. These solutions expand the plasma volume and the ECV Crystalloids tend to remain in the intravascular space for ~ 30 minutes before moving to the ECF.

When is the incidence of cerebral vasospasm. When is it most likely to occur?

It occurs in about 25% of patients following SAH and is most likely 4-9 days following SAH

What is Beck's triad? What conditions are associated with it?

It occurs in patients with acute cardiac tamponade Hypotension, JVD, muffled heart tones

Where do the roots turn into trunks?

Just beyond the lateral border of the scalene muscles

What is the MOA for class 3 anti-dysrhythmics?

K channel blockers Prolongs phase 3 repolarization (increases QT) Increases effective refractory period Ex: amiodarone, bretylium

Presentation of Adrenal Insufficiency

KAM CAN HAM Knees, elbows, knuckles, lips and buccal mucosa hyperpigmented Androgen, Mineralocorticoid & Glucocorticoid ⬇️ Muscle weakness/fatigue CRH or ACTH release ⬇️ (secondary) d/t exogenous steroid use. Addison's (primary): Adrenal glands don't secrete enough steroid hormone (most common is autoimmune) N/V HOTN, Hypoglycemia, Hyponatremia, Hyperkalemia Anorexia Metabolic acidosis (mild)

What is the treatment for Conn's syndrome?

KANT -K+ supplementation -Aldosterone antagonists → spironolactone or eplerenone -Na+ restriction -Tumor removal

What is the best IV induction agent for the patient with tetralogy of Fallot?

Ketamine (1-2 mg IV or 3-4 mg IM) is the best agent, it increases SVR and reduces shunting

What is the primary site of action for epidural anesthesia?

LA in the epidural space must first diffuse through the dural cuff before they can block the nerve roots. LA also leak through the intervertebral foramen to enter the paravertebral area. In this area, LA can cause multiple paravertebral blocks

How do you block the radial nerve in the forearm?

LA is injected between the biceps tendon and brachioradialis

What drugs are capable of causing methemoglobinemia?

LA-benzocaine, cetacaine, prilocaine, EMLA cream Other- SNP, NTG, sulfonamides, phenytoin

What are the maximum recommended peak inspiratory pressures for an LMA unique, LMA proseal, and LMA supreme?

LMA unique- < 20cm H2O LMA proseal and LMA supreme < 30 cm H2O

Laminar flow is dependent on ______ according to what law?

Laminar flow is dependent on gas viscosity- dictated by Poiseuille

Which law describes the relationship between aortic diameter and the risk of aortic rupture in the patient with AAA?

Laplace *Surgical correction recommended when the aneurysm > 5.5cm or if it grows >0.6-0.8 cm/year

Which opioid has the largest volume of distribution? Which has the smallest?

Largest = Fentanyl Smallest = Remifentanil

*GBS* usually persists for about ______ weeks and resolves with a full recovery in about _______ weeks.

Lasts 2 weeks Full recovery @ 4 weeks

What is the active metabolite of atracurium and cisatracurium? What is the clinical significance?

Laudanosine-capable of producing seizures

How does lean body mass change in the elderly? -Why is this important?

Lean body mass decreases as a function of reduced muscle mass. This causes: Decreased BMR Decreased TBW Decreased blood volume Decreased plasma volume Decreased volume of distribution for hydrophilic drugs Decreased neuromuscular reserve Hypothermia sets in faster

A *Left to Right shunt* occurs when PVR is ____________ than SVR. (greater/less than?)

Less than

What are the consequences of a CPP than exceeds the limit of autoregulation?

Less than 50- vessels are maximally dilated, CBF becomes pressure dependent, risk of cerebral hypoperfusion 50-150- range of autoregulation, CBF is constant over a range of pressures >150- Vessels maximally constricted, CBF becomes pressure dependent, risk of cerebral edema and hemorrhage

Define LD50

Lethal dose 50: The dose that will produce death in 50% of the population

What are s/s of gallstones?

Leukocytosis Fever RUQ pain- pain is worse on inspiration = Murphy's sign

Signs and symptoms of carcinoid crisis

Life-threatening -tachycardia -HTN or hypotension -Intense flushing -Abd pain -Diarrhea

Disadvantages of crystalloids

Limited ability to expand plasma volume- increases volume for 20-30 minutes. Increases potential for peripheral edema. Large volume of NaCl = hyperchloremic metabolic acidosis. Increased chloride causes increased bicarb excretion by the kidney Dilutional effect on albumin- reduces capillary oncotic pressure Dilutional effect on coagulation factors

Discuss the use of lipid emulsion for the treatment of LAST.

Lipid emulsion acts as a lipid sink- an intravascular reservoir that sequesters LA and reduces plasma concentration.

What is the Meyer-Overton rule?

Lipid solubility is directly proportional to the potency of an inhaled anesthetic. -Implies that depth of anesthesia is determined by the number of anesthetic molecules dissolved in the brain

What determines LA potency?

Lipid solubility is the primary determinant of potency. The more lipid soluble a LA, the easier it is for the molecule to traverse the neuronal membrane. Because more drug enters the neuron, there will be more of it available to bind to the Na channel An intrinsic vasodilating effect is the secondary determinant of potency. Vasodilation increases uptake into the systemic circulation, and this reduces the amount of LA available to anesthetize the nerve

Rank the opioids from the most lipophilic to the most hydrophilic. How does lipophilicity affect rostral spread in the subarachnoid space?

Lipophilic = sufentanil and fentanyl Hydrophilic = hydromorphone and morphine Hydrophilic drugs tend to remain in the subarachnoid space and travel towards the brain Lipophilic drugs tend to diffuse out of the subarachnoid space and enter the systemic circulation

How is vecuronium eliminated?

Liver 40-50% Renal 50-60%

What factors decrease the specific gravity of CSF?

Liver disease: third spacing ⬇️ hyperosmality Jaundice: kind of like liver dz Warmer temperature: allows for diffusion of molecules

How is rocuronium eliminated?

Liver elimination >70% Renal elimination 10-25%

Discuss glycogenesis, glycogenolysis and gluconeogenesis. -What is the stimulus for each? -How does each affect serum glucose?

Liver is an important regulator of serum glucose, and also clears insulin from the circulation. Patients with liver failure are at risk of hypoglycemia

What is the definitive treatment for alpha-1 antitrypsin deficiency?

Liver transplant

What is the definitive treatment for hepatorenal syndrome?

Liver transplant

How do you calculate the loading dose for an IV medication?

Loading dose = (VD x desired plasma concentration) /bioavailability -For IV, bioavailability is always 1 -PO encounters metabolism, bioavailability will be < 1

What is the functional unit of the liver?

Lobule: histologic unit. Classic functional unit Acinus: Functional unit. Cells grouped into concentric zones centered around portal triad.

Where are peripheral chemoreceptors located? What are their function?

Located in carotid bodies (Nerves of Hering to CN IX) Located in aortic arch (CN X) Respond to decreased O2, increased CO2, and increased H+

Where are central chemoreceptors located? What is their function?

Located in medulla Responds to the H+ concentration in the CSF

Chronic consumption of what food can produce a syndrome that resembles hyperaldosteronism?

Long term licorice ingestion (glycyrrhizic acid) causes a syndrome that highly resembles hyperaldosteronism (Conn's syndrome)

Presentation of hypermagnesemia

Loss of DTRs 4-6 mEq/L or 10-12 mg/dl Respiratory depression - 6.5-7.5 mEq/L or > 18mg/dl Cardiac arrest- >10 mEq/L or > 25mg/dl

Where are leaks in the anesthesia machine most likely to occur?

Low pressure system

Which inhalation agents are most affected by the slower FA/FI caused by a *cyanotic shunt*?

Low solubility agents: - Des - N20

How is lymph returned to the systemic circulation?

Lymph is returned to the venous circulation by way of the thoracic duct at the juncture of the internal jugular and subclavian vein. You can injury the thoracic duct during venous cannulation. Since the thoracic duct is larger on the left side, there is a greater risk of chylothorax (lymph in the chest) during left sided IJ insertion

How does MAC change in the elderly?

MAC decreases by 6% each decade of life after age 40

How do we quantify anesthetic potency? -What is this value for each inhalation agent?

MAC is a measure of potency Iso = 1.2 Sevo = 2 Des = 6.6 N2O = 104

How does MAC change during pregnancy

MAC is decreased by 30-40% due to increased progesterone

How is the anesthetic requirement altered in the alcoholic patient? -Why?

MAC is decreased if acutely intoxicated Increased in chronic ETOH user ETOH potentiates GABA- increased effect of benzos Inhibits NMDA receptors

What enzymes metabolize NE and Epi? What is the final metabolic by-product?

MAO COMT Final byproduct is vanillylmandelic acid (VMA)

What drugs extend or enhance the hypoglycemic effect of insulin?

MAOIs Salicylates Tetracycline

What is the calculation for mean arterial blood pressure?

MAP = SBP + 2DBP/3

What is the formula for SVR? What are normal values?

MAP-CVP/CO x 80 Normal 800-1500dynes/sec/cm5

What are *6 EARLY indicators* of MH?

MET WIT Masseter spasm EtCO2 ⬆️ Tachypnea Warm soda lime Irregular rhythm Tachycardia

What is the MOA of the dipeptidyl-peptidase-4 inhibitors?

MOA- Increase insulin release from pancreatic beta cells and decrease glucagon release from alpha cells. Ex: Suffix- liptin Key facts: Risk of hypoglycemia

What is the MOA of the amylin agonists?

MOA- decrease glucagon release from pancreatic alpha cells and reduce gastric emptying Ex: pramlintide Key facts: Risk of hypoglycemia if co-administered with insulin

What is the MOA of thiazolidinediones?

MOA- decrease peripheral insulin resistance, and increase hepatic glucose utilization Ex: Rosiglitazone, pioglitazone Key facts: Does NOT cause hypoglycemia Black box warning d/t risk of CHF

What is the MOA of the biguanides?

MOA- inhibit gluconeogenesis and glycogenolysis in the liver and decrease peripheral insulin resistance Ex: Metformin Key facts: -Does not cause hypoglycemia -risk of metabolic acidosis -Often used for PCOS

What is the MOA of alpha-glucosidase inhibitors?

MOA- slows digestion and absorption of carbohydrates from the GI tract Ex: Acarbose, Miglitol Key facts- Does not cause hypoglycemia

What is the MOA of the meglitinides?

MOA- stimulate insulin secretion from pancreatic beta cells Ex: Repaglinide, nateglinide Key facts: Risk of hypoglycemia

What is the MOA of the glucagon-like peptide-1 receptor agonists?

MOA: Increases insulin release from beta cells, decrease glucagon release from alpha cells, and prolongs gastric emptying. Ex: Exenatide, liraglutide Key facts: risk of hypoglycemia

How does Cushing's syndrome present? Why?

MOWS HIS HAM Mood disorder Osteoporosis Weight gain Syndrome = too much cortisol Hyperglycemia Increased risk of infection Skeletal muscle weakness HTN (Na+ and water retention) & Hypokalemia (K+ wasting) Androgenic effects: Women become masculinized, men become feminized Metabolic alkalosis (K+ wasting)

Pathophysiology of pyloric stenosis

MR KAL Metabolic alkalosis from Vomiting = hyponatremic, hypokalemic, hypochloremic, Respiratory acidosis from lungs compensating Kidneys try to compensate initial alkalosis by excreting HCO3 Aldosterone ⬆️ to maintain electroneutrality = kidneys lose hydrogen to the urine = acidification of the urine despite HCO3. LATE complication = metabolic acidosis.

Which BB have LA properties? What is the other name for this?

MSA Propranolol Acebutolol

Causes of anion gap acidosis

MUDPILES Methanol Uremia Diabetic ketoacidosis Paraldehyde or Phenformin Iron tablets or Isoniazid Lactic acidosis, Ethylene glycol Salicylates

What is the difference between macro and microshock?

Macroshock- a comparatively larger amount of current that is applied to the external surface of the body. The impedence of the skin offers a high resistance, so it takes a larger current to induce VF Microshock- current is applied directly to the myocardium, so it takes a significantly smaller amount of current to induce VF.

What is the treatment for torsades de pointes?

Mag sulfate Cardiac pacing to increase the HR will reduce AP duration and QT interval

What are the hemodynamic goals for the patient with a right to left shunt (Cyanotic shunt)?

Maintain SVR Decrease PVR - hyperoxia - hyperventilation - avoid lung hyperinflation

How can you prevent or minimize renal injury in the patient with rhabdomyolysis?

Maintenance of RBF and tubular flow with IV hydration Osmotic diuresis with mannitol UOP should be >100-150ml/hr NaHCO3 or acetazolamide to alkalize the urine

What prenatal finding suggests esophageal atresia? -How is the diagnosis confirmed after birth?

Maternal polyhydramnios is a key diagnostic indicator for TEF Diagnosis is confirmed by inability to pass a gastric tube into the stomach. Other: choking, coughing, cyanosis during oral feeding

What is mediastinoscopy and why is it performed?

Mediastinoscopy is performed to obtain biopsy of the paratracheal lymph nodes at the level of the carina, this helps the surgeon stage the tumor prior to resection

Describe A&P of oculocardiac reflex

Mediated via CN 5 and CN 10 Afferent branch= long and short ciliary nerves to ciliary ganglion to ophthalmic division V1 of trigeminal nerve to gasserian ganglion Treatment- ask surgeon to remove stimulus, 100% FiO2, proper ventilation, deepen GA, can give anticholinergic

Describe the presentation of thyroid storm

Medical emergency- Can occur in hyperthyroid AND euthyroid patients -Brought on by stressful events -Most commonly occurs 6-18 hours after surgery

Describe the 4 areas in the respiratory center

Medullary centers Dorsal respiratory center- inspiratory pacemaker Ventral respiratory center- active during expiration Pontine respiratory centers Pneumotaxic center in upper pons- inhibits the DRC Apneustic center in lower pons- stimulates the DRC

Discuss the co-administration of meperidine and MAO inhibitors.

Meperidine + MAOIs cause serotonin syndrome Meperidine is a weak serotonin reuptake inhibitor S/Sx= hyperthermia, AMS, hyperreflexia, seizures, death

Which opioid is most likely to cause QT prolongation?

Methadone

What induction agent is the gold standard for ECT? -Why? -What is the induction dose?

Methohexital is the gold-standard for ECT. It decreases the seizure threshold and produces a better quality seizure - Dose 1-1.5mg/kg

What is the treatment for methemoglobinemia? How does it work?

Methylene blue 1-2mg/kg up to max of 7-8mg/kg Reduces methemoglobin back to hemoglobin

Which opioid antagonist is least likely to reverse respiratory depression? Why?

Methylnaltrexone has a quaternary amino group that prohibits its passage across the BBB Since it doesn't enter the brain, it doesn't reverse respiratory depression Useful for mitigating the peripheral effects of opioids, such as opioid-induced bowel dysfunction

What is the treatment for TURP syndrome?

Mi SLITT Midazolam for seizures Support O2 & CV Labs & 12-lead EKG If Na+ > 120 mEq/L, restrict fluids & give Lasix. Na+ < 120 mEq/L give 3% NaCl at < 100 mL/hr Tracheal intubation and mechanical ventilation if the patient has difficulty with oxygenation and/or pulmonary edema. Tell surgeon to abort procedure

What ligaments are penetrated during the midline approach to the epidural space? How about the paramedian approach?

Midline: supraspinous, interspinous, ligamentum flavum Paramedian: ligamentum flavum

What is the best TEE view for diagnosing myocardial ischemia?

Midpapillary muscle level in short axis

Mild and severe preeclampsia

Mild: <160SBP <110DBP <5g/24 hour protein or <3 dipstick >500ml 24 hour urine Edema No pulmonary edema, cyanosis headache, visual impairment or epigastric pain Severe: essentially the numbers are greater than rather than less than (except urine is less than). Additionally they will have all of the symptoms above

How should third space losses be replaced in the neonate?

Minimal surgical trauma = 3-4 ml/kg/hr Moderate surgical trauma- 5-6 ml/kg/hr Major surgical trauma- 7-10 ml/kg/hr As a general rule, 3rd space losses are not included in the first hour of anesthesia

What concept is analogous to ED50 for local anesthetics?

Minimum effective concentration (Cm) is the concentration of LA that is required to block conduction. It is analogous to ED50 or MAC -Fibers that are more easily blocked have a lower Cm -Fibers that are resistant to blockade have a higher Cm

What is the difference between minute ventilation and alveolar ventilation?

Minute ventilation is the amount of air in a single breath multiplied by the number of breaths/min Alveolar ventilation only measures the amount of minute ventilation available for gas exchange- it removes anatomic dead space from the equation

What is closing volume, and what increases it?

Mnemonic- CLOSE-P COPD, LVF, Obesity, supine, Extreme age, pregnancy

Discuss DKA

More common with Type 1 DM Usually caused by infection Not enough insulin = ketoacidosis, hyperosmolarity from increased glucose, and dehydration Patient is hyperglycemic (>250mg/dl) but cells are starved for fuel Metabolic acidosis = Kussmaul respirations Acetone = fruity smelling breath Treatment- volume resuscitation, insulin, K + after acidosis subsides

What is the active metabolite of morphine, and why is it a problem?

Morphine is conjugated to morphine-3-glucuronide (inactive) and morphine-6-glucuronide (active) Impaired renal function decreases MP6 excretion and causes accumulation and respiratory depression

Discuss the use of opioids in the patient with CKD

Morphine is metabolized to morphine-6-glucuronide. This product is more potent than morphine, and it relies on renal excretion. Accumulation can contribute to respiratory depression. Meperidine is metabolized to normeperidine. Accumulation of normeperidine can cause convulsions. Fentanyl, sufentanil, alfentanil, and remifentanil do not produce active metabolites and are better choices with renal failure. Hydromorphone may or may not produce an active metabolite.

What are the pros and cons of general anesthesia for cesarean section?

Mortality is 17x higher with GA Failure to successfully manage the airway is the most common cause of maternal death Difficult things about GA with Moms MAD MD Mask Aspiration potential DL MHxf Depressed neonate CNS

What is the primary site of metabolism for the commonly used BB? What are 2 exceptions?

Most BB depend on liver for metabolism. 2 exceptions- esmolol (RBC esterases) Atenolol- Kidneys

What surgical procedure presents the most significant risk of ION? What are other procedure and patient risk factors?

Most common after spine surgery in the prone position Procedure risk factors Prone position, Wilson frame, Long case, High EBL, Low ratio of colloid to crystalloid resuscitation, Hypotension Patient risk factors- Male sex, Obesity, DM, HTN, Smoking, Old age, Atherosclerosis

What is the most common cause of perioperative AKI? Who is at highest risk?

Most common cause- ischemia-reperfusion injury At risk patients- J CHAPPS Jaundice CHF High risk surgery- use of AoXc and liver transplant Advanced age Pre-existing kidney disease Prolonged renal hypoperfusion Sepsis

What is the most common etiology of hyperthyroidism? What are the other causes?

Most common- Grave's disease (autoimmune) MG Multinodular goiter Carcinoma Pregnancy Pituitary adenoma Amiodarone

What is the most common etiology of hypothyroidism? What are the other causes?

Most common- Hashimoto's thyroiditis (autoimmune) Iodine deficiency Hypothalamic-pituitary dysfunction Neck radation Thyroidectomy

What are the 1st and 2nd most common causes of chronic hepatitis?

Most common-alcoholism Second- Hep C (most common cause but not the most common hepatitis)

What are the common causes of fetal deceleration

VEAL CHOP Varible = cord compression Early = head compression Accelerations = Ok or O2 Late = placental insufficiency

Can you tell if a drug is an acid or a base by looking at it's name? How?

Most drugs are weak acids or weak bases, usually prepared as a salt that dissociates in solution -Weak acids-paired with positive ion such as Na, Ca, Mag Ex: sodium thiopental -Weak bases are paired with negative ions such as Cl or sulfate Ex: lidocaine hydrochloride, morphine sulfate

Why do desflurane and isoflurane sometimes increase heart rate?

Most likely d/t SNS activation from respiratory irritation -rapid increases in desflurane = tachycardia Pulmonary irritation = SNS activation = increase NE release = B1 stimulation -Tachycardia can be minimized with opioids, A2 agonists or B1 antagonists

How do opioids affect biliary pressure, gastric emptying and peristalsis?

Mu receptor stimulation Biliary pressure- contraction of sphincter of Oddi increases biliary pressure (reversed by naloxone or glucagon) Gastric emptying is prolonged Peristalsis is slowed = constipation

Pretend for a moment that mu receptor subtypes exist. What are the physiologic effects of Mu-1, mu-2, and mu-3 receptor stimulation?

Mu-1 Analgesia (supraspinal and spinal) and bradycardia Mu-2 Analgesia (spinal only), respiratory depression, constipation, physical dependence Mu3- immune suppression

How does the source of blood products affect the risk of TRALI?

Multiparous women History of blood transfusion History of organ transplant

How should the NPO fluid deficit be replaced?

Multiply the patient's hourly fluid maintenance rate by the number of hours of NPO time → replace this over three hours -1st hour → 50% -2nd hour → 25% -3rd hour → 25%

Which nerve is most likely to be missed during an axillary block? Which terminal branch is not included in an axillary block?

Musculocutaneous nerve resides in the coracobrachialis muscle- not part of the neurovascular sheath that surrounds the axillary artery. This nerve must be blocked separately. Ironically, the axillary nerve is not included in an axillary block

A patient suffers from retained placental fragments. What IV medication can you give to help with the extraction?

NTG

What are examples of isotonic solutions- both crystalloids and colloids

NaCl 0.9% LR Plasmalyte A 5% albumin 6% voluven 6% Hespan

How does sodium bicarbonate affect LA onset? Are there any other benefits?

NaHCO3 shortens onset time Alkalinization increases the # of lipid soluble molecules Can alkalize LA by mixing 1ml of 8.4% NAHCO3 with 10mL of LA Addition of NaHCO3 reduces pain during injection

Which opioid antagonist has the longest DOA?

Naltrexone No significant first-pass metabolism, can be given orally with a DOA of up to 24 hours

How does myocardial compliance change in the elderly?

Myocardial compliance decreases Impaired relaxation may cause diastolic dysfunction Atrial kick becomes more important for ventricular priming and maintenance of CO

What factors cause decreased contractility?

Myocardial ischemia, severe hypoxia, acidosis, hypercapnia, hyperkalemia, hypocalcemia, VA, propofol, BB, CCB

What is the relationship between etomidate and myoclonus?

Myoclonus= involuntary skeletal muscle contractions, dystonia, or tremor -Exact MOA is unclear, but is likely d/t imbalance between excitatory and inhibitory pathways in the thalamocortical tract. It is NOT a seizure

What is the difference between myxedema coma and cretinism?

Myxedema coma occurs with end-stage hypothyroidism. Coma is a consequence (not a cause) of severely impaired thyroid function. Cretinism is caused by neonatal hypothyroidism that leads to physical and mental retardation.

Name 2 drugs that are most likely to reduce the reliability of the BIS value

N2O - increases the amplitude of high frequency activity and reduces the amplitude of low frequency activity. ** does not affect BIS value** Ketamine- increases high frequency activity. This can produce a BIS value that is higher than the level of sedation/anesthesia would otherwise suggest

What is the relationship between N2O and bone marrow depression?

N2O inhibits methionine synthase and folate metabolism = megaloblastic anemia

Presentation of hypercalcemia

NAH PMS Nausea Abdominal pain HTN Psychosis Mental status changes Seizures

What is necrotizing enterocolitis, and who is at risk?

NEC is necrosis of the bowel; usually the terminal ileum and proximal colon. The pathophysiology is not completely understood, but can be the result of early feeding. Impaired absorption by the gut = Stasis Infection Bacterial overgrowth. Bowel perforation risk At risk: Premature < 32 weeks Low birth weight < 1500g

Which cerebral receptors are stimulated by N2O

NMDA antagonism Potassium 2P-channel stimulation

Can an O2 analyzer alert you to a circuit disconnect?

NO

Can the *fail-safe* or *proportioning* devices detect an oxygen pipeline crossover?

NO

Do neuraxial opioids cause sympathectomy, skeletal muscle weakness, and/or changes in proprioception?

NO

Does a *injector (desflurane) vaporizer* account for elevation compensation?

NO

What factors are in the intrinsic pathway?

VIII, IX, XI, XII If you can't buy the intrinsic pathway for 12$, you can buy it for 11.98

What is coarctation of the aorta? Which syndrome is highly associated with this anomaly?

Narrowing of the thoracic aorta, in the vicinity of the ductus arteriosus. It typically occurs just before or after the ductus arteriosus. In rare instances it occurs proximal to the LSC artery. Turner syndrome is highly associated with coarctation of the aorta.

While a patient is spontaneously ventilating, you notice that a FGF of 10L/min is needed to fill the breathing bag and determine that the scavenger is malfunctioning. Which mechanism has failed?

Negative pressure relief valve

Do LA change the RMP or the TP?

Neither- LA do not affect RMP or TP

Discuss the MOA of neuraxial opioids

Neuraxial opioids inhibit afferent pain transmission in the substantia gelatinosa (lamina II) of the dorsal horn Neurotransmission is reduced by decreased cAMP, decreased Ca conductance (pre-synaptic neuron), and increased K conductance (post-synaptic neuron) Epidural opioids also diffuse into the systemic circulation, where blood delivers them to opioid receptors throughout the body.

Compare and contrast the regional anesthetic techniques that can be used for first and second stage labor pain

Neuraxial techniques that provide analgesia to T10-L1 during the first stage of labor must be extended to cover S2-S4 during the second stage of labor.

How can you differentiate neurogenic shock from hypovolemic shock?

Neurogenic = bradycardia, hypotension, hypothermia with pink/warm extremities Hypovolemic shock = tachycardia, hypotension, cool/clammy extremities

Is it ever safe to use an oxygen cylinder in the MRI suite?

Never take a cylinder into the MRI scanner unless it is made of a non-magnetic material, such as aluminum An MRI safety cylinder will have 2 colors: most of the tank is silver, only the top is the color that signifies the gas it contains

List the 3 types of cholinergic receptors. -Where are each of these found inside the body?

Nicotinic type M- found at NMJ Nicotinic type N- found in CNS and preganglionic fibers at autonomic ganglia (SNS & PNS) Muscarinic- found in CNS and postganglionic PNS fibers at effector organs

Unlike gas-driven bellows which automatically add 2 - 3cmH20 PEEP d/t design of ventilator spill valve, the *piston vent* adds ________ PEEP.

No PEEP

How does neuraxial anesthesia affect renal and hepatic blood flow?

No change so long as BP is not changed

Can you reverse a phase 2 block with succinylcholine?

No- have to wait it out

Is N2O safe in the patient with TBI

No- injuries may only become evident after induction of anesthesia and PPV.

Discuss how anesthesia in the lateral decubitus position affects the V/Q relationship.

Nondependent lung- moves from flatter region (less compliant) to an area of better compliance (slope) Ventilation is optimal Dependent lung- Moves from the slope to the lower, flatter area of the curve (less compliant). Perfusion is best in this lung. A reduction of alveolar volume contributes to atelectasis

What is the normal value for PLT? What are the critical values?

Normal 150,000-300,000 < 50,000 increases surgical bleeding risk < 20,000 increases spontaneous bleeding risk

How do you interpret the results of the dibucaine test?

Normal = 80 Abnormal = 20 means atypical variant is present, dibucaine is unable to inhibit PChE

5 causes of hypoxemia- which are reversed by supplemental O2?

Normal A-a gradient- Reduced FiO2 or hypoventilation- both fixed wth O2 Increased A-a gradient- Diffusion limitation, V/Q mismatch- both fixed by O2 Shunt- not fixed with O2 because pulmonary blood is bypassing alveoli

When do GFR and renal tubular function achieve full maturity?

Normal GFR is reached at 8-24 months of age Before maturation, neonates do a poor job of conserving water, so they are intolerant of fluid restriction. On the flip side, they can't excrete large volumes of water, so they don't do great with fluid overload either. Normal tubular function is reached at 2 years of age In the first few days of life, the neonate is an obligate sodium loser. After that, they are better able to retain sodium than excrete it. Neonates also have a tendency to lose glucose in the urine.

How does a flow volume loop appear with an intrathoracic obstruction?

Normal during inspiration, abnormal during expiration

What does the pulmonary flow volume loop look like with obstructive disease?

Normal inspiration, expiratory obstruction (someone took a bite out of the ice cream cone)

What is the normal ACT? What value should be achieved prior to transitioning to CPB?

Normal is 90-120 Should be >400 prior to CPB ACT is measured before heparin administration, 3 minutes after it's given, and every 30 minutes after

What is the active metabolite of meperidine, and why is it a problem?

Normeperidine is 1/2 as potent as parent compound reduces the seizure threshold and increases CNS excitability Impaired renal function = impaired excretion = accumulation = seizures

What should the colors of each E-cylinder gas tank be according to the WHO?

O2 = white N20 = blue Air = black and white

What are the 5 tasks of oxygen in the anesthesia machine?

O2 pressure failure alarm O2 pressure failure device O2 flowmeter O2 flush valve Ventilator drive gas (if pneumatic bellows)

What factors decrease MAC?

OH CAMP PALP

What are the diagnostic criteria for TRALI?

OPIN Onset < 6 hours following transfusion PaO2/FiO2 < 300 mmHg or SpO2 < 90% on RA Infiltrates Bilateral on frontal CXR Normal PAOP

Which regulatory agency sets standards for acceptable occupational exposure to volatile anesthetics?

OSHA

Diagnostic criteria for gestational HTN?

Occurs after 20 weeks HTN

Diagnostic criteria for eclampsia?

Occurs after 20 weeks HTN Proteinuria Edema Seizures

Diagnostic criteria for preeclampsia?

Occurs after 20 weeks HTN Proteinuria edema

Discuss the pathophysiology of renal osteodystrophy

Occurs d/t ⬇️ vitamin D production & secondary hyperparathyroidism ⬇️ vitamin D = ⬇️ Ca absorption in GIT = ⬆️ PTH release = demineralizes bone to restore the serum Ca Net result is decreased bone density and increased risk of bone fractures

How does the ionization characteristics of alfentanil influence its onset of action?

Of all the opioids, alfentanil has the fastest onset pKa is 6.5, which is < physiologic pH which makes it 90% unionized, 10% ionized Has a low Vd, and high degree of plasma protein binding

List 4 examples of ADP receptor inhibitors, and how long each must be discontinued prior to surgery

One-Twosday Tica TOOK-3 Prassed WEEK Cloves TWOweeking Ticlothes Ticagrelor 1-2 days Prasugrel 2-3 days Clopidogrel - 7 days Ticlopidine - 14 days

What is the onset, DOA, and clearance mechanism for ketamine?

Onset -IV = 30-60 seconds -IM = 2-4 minutes -PO = variable Duration- 10-20 minutes Clearance - liver (CYP450 enzymes) *Active metabolite- Norketamine (1/5-1/3 potency of ketamine) *Chronic use induces liver enzymes (burn patients)

What is the best location to assess the onset of neuromuscular blockade? How about recovery?

Onset- best measured at orbicularis oculi muscle with the facial nerve Recovery- best measured at adductor pollicis with ulnar nerve

4 types of breathing circuits, and examples of each

Open- insufflation, face mask, NC, open drop Semi-open- Mapleson circuit, circle system if FGF > Vte Semi-closed- Circle system if FGF < Vte Closed- Circle system with low FGF and closed apl

Discuss the use of succinylcholine in the patient with renal failure

Opening of the nAChR at the NMJ can increase serum K by 0.5-1mEq/L for up to 10-15 minutes Succs is safe in patients with renal failure and a normal K level In the patient with hyperK, the normal response to succs may increase serum K to a dangerous level

How do opioids affect thermoregulation?

Opioids reset the hypothalamic temperature set point → decreased core body temperature

Discuss damping and the interpretation of the high pressure flush test

Optimal waveform morphology balances the amount of damping with the amount of distortion from the transducer system. The high pressure flush test helps us determine this when we flush the system and observe the oscillations that result. Optimally damped- baseline re-established after 1 oscillation Under-damped- baseline is re-established after several oscillations (SBP overestimated, DBP underestimated, MAP accurate) Over-damped- baseline re-established with no oscillations (SBP underestimated, DBP overestimated, MAP accurate) Can be d/t air bubble or clot in pressure tubing, or low flush bag pressure

What is the difference between osmosis and diffusion?

Osmosis- net movement of water across a semipermeable membrane, where the direction of water movement is driven by the difference in solute concentration on either side of the membrane (only the solvent moves) Diffusion is the net movement of molecules from a region of high concentration to a region of low concentration (solvent and solute move)

How does mannitol reduce ICP? What problems can arise when mannitol is used in this way?

Osmotic diuresis (0.25-1g/kg) increases serum osmolarity and pulls water across the BBB into the blood stream If the BBB is disrupted, mannitol enters the brain and promotes cerebral edema Mannitol transiently increases blood volume, which can increase ICP and stress a failing heart

What is osmotic pressure, and what is its primary determinant?

Osmotic pressure is the pressure of a solution against a semipermeable membrane that prevents water from diffusing across that membrane. Osmotic pressure is a function of the number of osmotically active particles in solution. Not a function of molecular weights

Discuss the presentation of the child who presents with foreign body aspiration

Over 60% of children with FBA present with the classic triad of cough, wheezing, and decreased breath sounds on the affected side (usually the right) Airway obstruction significant enough to impair gas exchange can quickly progress to hypoxemia, cyanosis, AMS, cardiac arrest and death. Supraglottic obstruction = stridor Infraglottic obstruction = wheezing

What does an *oxygen analyzer* monitor?

Oxygen concentration (NOT pressure)

Why is the neonate's minute ventilation higher than the adult?

Oxygen consumption and CO2 production are twice those of the adult. Therefore, the neonate must increase alveolar ventilation accordingly. It is metabolically more efficient to increase the RR than it is to increase the Vt. This explains why newborns have a high RR, but the Vt is the same as an adult on a per weight basis- 6ml/kg

Give 4 examples of how the hypoxia prevention safety device (proportioning device) might permit the delivery of a hypoxic mixture

Oxygen pipeline crossover Leaks distal to the flowmeter valves Administration of a 3rd gas (helium) Defective mechanic or pneumatic components

What is the difference between the oxygen pressure failure device and the hypoxia prevention safety device?

Oxygen pressure failure device AKA Fail safe- shuts off and/or proportionally decreases N2O flow if O2 pressure drops below 20 psi Hypoxia prevention safety device AKA proportioning device- prevents you from setting a hypoxic mixture with the flow control valves. Limits N2O flow to 3x the O2 flow (N2O max ~75%)

Where is oxytocin synthesized? Where is it released? What are the potential side effects?

Oxytocin is synthesized in the supraoptic and paraventricular nuclei of the hypothalamus. It is released from the posterior pituitary gland. You can give it IV (diluted with IVF) or the OB can inject it directly into the uterus. SE: WaHHR C Water retention Hyponatremia Hypotension Reflex tachycardia Coronary vasoconstriction

What drugs/conditions exacerbate *SLE*? PISSED CHIMP

P = pregnancy I = infection S = surgery S = stress E = enalapril D = D-penicillamine C = captopril H = hydralazine I = isoniazid M = methyldopa P = procainamide

What are relative contraindications for ESWL?

Pacemaker/ICD Calcified Aneurysm of the Aorta or Renal artery Untreated UTI Obstruction beyond the renal stone Morbid obesity

Triggers that cause sickling of Hgb S

Pain Hypothermia Hypoxemia Acidosis Dehydration Anesthetic management focuses on avoiding these triggers

Anesthetic management of the patient with pyloric stenosis

PALAP Pyloromyotomy postponed until the fluid, electrolyte and acid-base status are optimized. Anticipate a full stomach, so empty the stomach before induction. Liberal hydration to correct dehydration. May require glucose supplementation. Awake intubation or RSI, and awake extubation. Postoperative apnea is common. This is possibly due to the fact that the CSF pH remains alkalotic even after serum acid-base status is normalized.

Recite the alveolar gas equation

PAO2 = FiO2 x (Pb-PH2O)- (PaCo2/RQ) Pb= atmospheric pressure PH2O = 47 RQ- 0.8

Describe the ventilatory management of the patient with CDH

PAPA PIP < 25-30 to minimize barotrauma and risk of pneumothorax in the good lung. Avoid conditions that increase PVR (hypoxia, acidosis, hypothermia) Pulse ox placed on LE can warn of increased IAP Abdominal closure may increase PIP-surgeon may create temporary ventral hernia to increase abdominal volume.

What are the risk factors for placental abruption? How does it present?

PC PECS PIH Chronic HTN Preeclampsia Excessive ETOH use Cocaine use Smoking Presents as painful vaginal bleeding- pain can be so severe it causes breakthrough pain when a functional epidural is in place.

Describe the fate of sodium at each location in the nephron

PCT: 65% Ascending limb LOH: 20% DCT: 5% CD: 5% Urine: 5%

What are 3 treatments for exacerbation of *MG*symptoms?

PIA Plasmapheresis Immunosuppression Anticholinesterase

Name 6 risk factors for RDS?

PIG MOB Pos pressure ventilation Intubation Gestation age Maternal DM Oxygenation Birth weight

What 1 thing is variable with *volume controlled ventilation*?

PIP

What 2 variables are fixed with *pressure controlled ventilation*?

PIP inspiratory time

When is PLT transfusion indicated in the neonate? What is the dose?

PLT is recommended for invasive procedures to maintain PLT >50,000 Dose if obtained from apheresis = 5ml/Kg Dose if pooled PLT concentrate = 1pack/10kg

Contrast the treatment of POD and POCD?

POD- treat underlying cause, antipsychotics, minimize polypharmacy POCD- no specific treatment, most cases are mild and tend to resolve after ~3 months **To minimize either/both conditions, best to use rapidly metabolized drugs**

What conditions increase the risk of torsades de pointes?

POINTES Phenothiazines Other meds (methadone, droperidol, amiodarone + hypoK) Intracranial bleed No known cause Type 1 antiarrhythmics Electrolyte disturbances (low K, Ca, or Mag) Syndromes - DiGeorge, Conns

What are high risk surgical procedures according to cardiac risk?

POLE Peripheral vascular surgery Open aortic surgery Long surgical procedure with significant volume shifts and/or blood loss Emergency surgery-especially in the elderly

What are the *cardiovascular complications* of *SLE*?

PRE HC Pericarditis Raynaud's Endocarditis HTN Conduction defects

What is the first-line medical treatment for *MG*? What are the consequences of ODing this drug?

PYRidostigmine (anticholinesterase) OD = cholinergic crisis, mimics s/sx of MG

Which NMB has a vagolytic effect?

Pancuronium d/t inhibition of M2 receptors at the SA node, stimulating the release of catecholamines, and inhibition of catecholamine reuptake in adrenergic nerves

Which NMBs should be avoided in the patient with hypertrophic cardiomyopathy?

Pancuronium-d/t vagolytic effect Atracurium d/t histamine release Mivacurium d/t histamine release

What is the risk of PFO?

Paradoxical embolism

What is the treatment of opioid induced skeletal muscle rigidity?

Paralysis/intubation

In which patient will the onset of sevoflurane be the fastest? Patient A has a HR of 55 bpm with a SV of 100ml/beat. Patient B has a HR of 60 bpm with a SV of 85ml/beat

Patient B -High CO removes more VA from the alveoli, so it slows the rate of rise of FA/FI

During endovascular coil placement for a cerebral aneurysm, the aneurysm ruptures. What is the best treatment at this time?

Patients who undergo endovascular coiling require heparinization during the procedure. If the aneurysm ruptures during the procedure, you should give protamine (1mg per 100U of heparin administered) MAP should be lowered into the low/normal range.

Name 2 patient populations who are at increased risk for developing methemoglobinemia

Patients with glucose-6-phosphate reductase deficiency do not possess methemoglobin reductase, so an exchange transfusion may be required. Fetal Hgb is relatively deficient in methemoglobin reductase, making it susceptible to oxidation. Neonates are higher risk for toxicity

What is the role of recombinant factor 7 in the management of hemophilia A and B? Whats the dose?

Patients with hemophilia A or B can develop inhibitors that prevent exogenous factor 8 or 9 from achieving a therapeutic goal. For a clot to form, the missing coagulation factor must be replaced or "bypassed". Recombinant factor 7 is a "bypass" agent because it skips over factor 8 or 9 in patients with inhibitors, allowing the patient to form clot. Dose is 90-120 mcg/kg Can also be used as "last-ditch" treatment for bleeding without identifiable cause. Dose is 20-40mcg/kg

Compare and contrast the phase 1 and phase 2 block in terms of TOF, DBS, and post-tetanic potentiation.

Phase 1 response to stimulation are diminished, but equal. No fade Phase 2 response to stimulation is characterized by fade No post-tetanic potentiation with a phase 1 block, but it is present with a phase 2 block

List the 3 phases of the SA node action potential and describe the ionic movement during each phase.

Phase 4- spontaneous depolarization- Leaky to Na (Ca influx occurs at the very end of phase 4) Phase 0- Depolarization- Ca influx Phase 3- Repolarization- K efflux

List 3 alpha antagonists. What is the MOA for each?

Phenoxybenzamine- long acting, nonselective, noncompetitive antagonist of A1 and A2 Phentolamine is a short acting, nonselective, competitive antagonist of A1 and A2 Prazosin is a selective A1 antagonist

Which acetylcholinesterase inhibitors pass through the blood brain barrier? -Which do not? Why?

Physostigmine is a tertiary amine- it passes through the BBB Edrophonium, neostigmine, and pyridostigmine are quaternary amines- they carry a positive charge that prevents them from passing through the BBB

Where is the pituitary gland located? What is another name for the anterior and posterior pituitary glands?

Pituitary gland resides in the sella turcica and is connected to the hypothalamus by the pituitary stalk Anterior = adenohypophysis Posterior = neurohypophysis

How do you perform a Bier block?

Place a double tourniquet on the patient, do not inflate Place 22g PIV in a distal peripheral vein of the operative extremity. Elevate extremity for 1-2 minutes to allow passive exsanguination Wrap the Esmarch bandage around the extremity to further exsanguinate it. Inflate the distal cuff Inflate the proximal cuff Deflate distal cuff Remove Esmarch

What conditions increase the risk of abnormal placental implantation?

Placenta Previa and Previous C sections

What are *pulmonary complications* of *RA*?

Pleural effusion Restrictive ventilatory dz - diffuse interstitial fibrosis - costochondral involvement limits chest rise

In the event of a fire, what are the 3 safety relief devices built into a cylinder that allow it to empty its contents in a slow and controlled way?

Plug, disk and a valve 1. Plug made of Wood's metal (melts at elevated temps) 2. Disk that ruptures under pressure 3. Valve that opens at elevated pressures

What is the greatest risk of a supraclavicular block? Why?

Pneumothorax The cupola of the lung is just medial to the first rib. It is higher on the right side. Tall, thin patients have a higher risk of this complication. Consider pneumothorax if the patient coughs or complains of chest pain during needle insertion or manipulation.

In which regions of the brain do halogenated anesthetics produce autonomic modulation?

Pons Medulla

Which populations tend to have a greater percentage of TBW % by weight? Which have less?

Populations with higher TBW - Neonates Populations with lower TBW - females, obese, elderly

What is the normal portal vein pressure? What value is diagnostic of portal HTN?

Portal perfusion pressure = portal vein pressure - hepatic vein pressure Normal portal vein pressure = 7-10, >20-30 mmHg is diagnostic for portal HTN Normal Sinusoidal pressure = 0 >5 = diagnostic for portal HTN

Which vessels supply blood to the liver? Which provides more flow? Which provides more oxygen?

Portal vein and hepatic artery Portal vein- 75% of liver blood flow, 50% of oxygen content Hepatic artery- 25% of liver blood flow, 50% of O2 content

What is the significance of the NBG pacemaker identification code?

Position 1 = chamber paced Position 2 = chamber sensed Position 3 = response to sensed event Position 4 = programmability Position 5 = Pacemaker can pace multiple sites

Contrast the onset of POD and POCD

Post-op delirium = early postop period POCD- weeks to months after surgery

Describe the glossopharyngeal innervation of the airway

Posterior 1/3 of tongue Soft palate Oropharynx Vallecula Anterior side of epiglottis

Which muscles abduct and adduct the vocal cords?

Posterior CricoArytenoid- Please come apart Lateral CricoArytenoid- Let's Close Airway

Where is the sural nerve blocked?

Posterior to the lateral malleolus Sural is 04:00

Where is the posterior tibial nerve blocked?

Posterior to the medial malleolus Tibial is 08:00

What is postrenal injury? What is the treatment?

Postrenal- obstruction Treatment- relieve the obstruction

How does hypermagnesemia affect neuromuscular blockade?

Potentiates NMB

Chromaffin cells in the adrenal medulla are stimulated by ______ _____ neurons

Preganglionic sympathetic neurons

Give 4 examples of how the hypoxia prevention device (proportioning device) might permit delivery of a hypoxic mixture.

Proportioning device will NOT prevent hypoxic mixture in the following circumstances: 1. O2 pipeline crossover 2. Leaks distal to flowmeter valves 3. Admin of a 3rd gas (helium) 4. Defective mechanic/pneumatic components

Pros and cons of awake extubation

Pros- airway reflexes intact, ability to maintain airway patency, decreased risk of aspiration Cons- Increased CV/SNS stimulation, increased coughing, increased ICP, increased IOP, increased IAP

Pros and cons of deep extubation

Pros-decreased CV/SNS stimulation, decreased coughing Cons- airway reflexes ineffective, increased risk of airway obstruction, increased risk of aspiration

3 mechanisms that promote renal vasodilation

Prostaglandins- inhibited by NSAIDs ANP Dopamine- 1 receptor stimulation

Describe the pathophysiology and treatment of protein C and S deficiency

Protein C produces an anticoagulant effect by inhibiting factors Va and VIIIa. This creates a feedback mechanism that prevents unnecessary clot formation. Protein S is a co-factor of protein C. (Helps it do its job) Deficiency in C or S can produce hypercoagulable state = increased risk of thrombosis Treatment- a thromboembolism is treated with heparin and transitioned to warfain. Patient's may or may not require life-long anticoagulation with warfarin

What factors determine LA duration of action?

Protein binding is the primary determinant of DOA. After injection, some molecules penetrate the epineurium, some diffuse away, and some bind to tissue proteins. The molecules that bind to proteins serve as a reservoir that extends the DOA Lipid solubility and intrinsic vasodilating activity are secondary determinants. Higher lipid solubility = longer DOA. A LA with intrinsic vasodilating activity will increase the rate of vascular uptake and shorten the DOA.

What types of surgical procedures are well suited for an axillary block? Which are not?

Provides anesthesia to upper extremity distal to the elbow Not recommended for procedures above the elbow

What are the 4 most important SE of neuraxial opioids? Which is the most common?

Pruritus (Most common) Respiratory depression (hydrophilic drugs are at higher risk d/t greater rostral spread) Urinary retention N/V

What are the SE of magnesium?

Pulmonary edema Hypotension Skeletal muscle weakness CNS depression Reduced responsiveness to ephedrine and phenylephrine

In addition to LAST, what are other potential complications of a large volume of tumescent anesthesia?

Pulmonary edema d/t circulatory overload

What disease process produces a restrictive pulmonary flow volume loop?

Pulmonary fibrosis

What is pulsus paradoxus?

Pulsus paradoxus represents an exaggerated decrease in SBP during inspiration (SBP falls by >10mmHg during inspiration) = impaired diastolic filling

Describe the pathophysiology and presentation of PDPH

Puncturing the dura causes CSF to leak from the subarachnoid space. As CSF pressure is lost, the cerebral vessels dilate. In addition, the brainstem sags into the foramen magnum, which stretches the meninges and pulls on the tentorium. These factors contribute to PDPH Classic presentation includes a fronto-occipital HA, may be accompanied by nausea, emesis, photophobia, diplopia, and tinnitus. In the upright position, gravity makes the HA worse.

What is the equation for mixed venous oxygen saturation? What are normal values?

Q = CO VO2 = O2 consumption SaO2 = loading of Hgb in arterial blood Normal 65-75%

How does ESWL affect cardiac conduction? -What is done to minimize this risk?

R on T phenomenon The pulse wave is timed to the R wave on the EKG to minimize the risk of

What is the indication to transfuse PRBCs?

RBC are transfused to increase CaO2 Hgb < 6 Decision to transfuse is guided by patient factors

Where does bilirubin come from? How is it cleared from the body?

RBC life cycle is 120 days. Aged RBCs are processed by the reticuloendothelial cells in the spleen. In the spleen, Hgb- heme- unconjugated bilirubin. Unconjugated bilirubin is lipopnilic. It is transported to the liver bound to albumin. The liver conjugates bilirubin with glucuronic acid. This increases its water solubility. Conjugated bilirubin is excreted into the bile, metabolized by intestinal bacteria, and eliminated in the stool.

How much of the RBF is filtered at the glomerulus? Where does the rest go?

RBF 1000-1250 ml/min GFR = 125ml/min or ~20% of RBF

What are the 3 primary causes of hypercapnia?

RID Rebreathing Increased CO2 production Decreased CO2 elimination

What are the *pulmonary complications* of *SLE*?

RIPPP Restrictive defect Interstitial lung dz w/ impaired diffusing capacity Pulmonary HTN Pulmonary emboli recurring Pleural effusion

Discuss RLN injury in the context of thyroidectomy

RLN innervates all of the intrinsic laryngeal muscles except the cricothyroid muscle. Injury to the RLN = airway obstruction -Unilateral injury = hoarseness -Acute bilateral injury = airway obstruction Have patient say letter 'E' or moon for RLN integrity Use a NIMs tube-can assess RLN integrity intraop At the end of the procedure, DL can be used to assess VC function and help identify glottic edema

Describe gastroschisis

RUN COLD Right of umbilicus Urgent (w/n 24hrs) No, not covered Closure same as omphacele Organs = bowel only Loss of fluid and heat is greater Disease a/w = prematurity

What is the *pathophys* of *transposition of the great arteries*?

RV gives rise to aorta LV gives rise to pulmonary artery

What is the etiology of opioid induced skeletal muscle rigidity?

Rapid IV administration of the potent IV opioids can cause skeletal muscle rigidity (mu receptor stimulation in CNS) Greatest resistance to ventilation occurs at the larynx

PK/PD profile of remifentanil

Rapid on/Rapid off mu agonist Contains an ester linkage = susceptible to hydrolysis by RBC and tissue esterases

Discuss the consequence of an epidural that is placed in the subdural space

Rare/unpreventable, tip of the epidural catheter is in the subdural space between dura and arachnoid. Neither catheter aspiration or a test dose will r/o subdural placement. Within 10-25 minutes after the epidural is dosed, the patient will experience symptoms of an excessive cephalad spread of LA. Because the subdural space is a potential space, it holds a very low volume. For this reason, the block height for a given amount of local anesthetic will be much higher than if the same volume was administered in the epidural space.

Define lusitropy

Rate of myocardial relaxation during diastole

What TOF ratio correlates with full recovery from neuromuscular blockade?

Ratio >0.9 @ adductor pollicis

The *size and direction* of shunt is dependent on what 3 factors?

Ratio of PVR:SVR - R to L shunt when PVR > SVR - L to R shunt when SVR > PVR Pressure gradients btwn cardiac chambers or artries involved Compliance of the cardiac chambers

Why are BB used to treat hyperthyroidism?

Reduce SNS stimulation and inhibit peripheral conversion of T4 to T3

What is the key function of the collecting duct?

Regulates final concentration of urine (variable depending on aldosterone and ADH)

What hormones are released from the anterior pituitary gland?

Remember "FLAT PiG" Follicle-stimulating hormone Luteinizing hormone Adrenocorticotropic hormone TSH Prolactin Growth hormone

What happens when you put acid in a basic solution? How about an acidic solution?

Remember "Like dissolves like" Acid in basic solution- drug will be highly ionized Acid in acidic solution- highly unionized

Discuss the relationship between remifentanil and opioid induced hyperalgesia. What drugs can prevent this phenomenon?

Remifentanil causes acute opioid induced hyperalgesia following discontinuation Post-op opioid requirements are particularly high in these patients Can be prevented with ketamine or mag

Can remifentanil be used for neuraxial anesthesia? -Why or why not?

Remifentanil powder is mixed with a free base and glycine to provide a buffered solution following reconstitution Glycine is an inhibitory neurotransmitter Causes skeletal muscle weakness, should not be administered in epidural or intrathecal space

What is leukoreduction, why is it used, and who does it benefit?

Removes WBCs from RBCs and PLT. Thus reducing the risk for CHF CMV transmission HLA alloimmunization Febrile nonhemolytic transfusion reactions

How is pancuronium eliminated?

Renal 85% Liver 15%

How does renal failure affect the dosing of acetylcholinesterase inhibitors after an aminosteroid NMB is administered?

Renal failure prolongs the DOA for both AchE inhibitors and aminosteroid NMB Since both drugs will remain in the body for a longer period of time, there is no need to adjust the dose of AchE inhibitor or redose it

Discuss the complications of an acute hemolytic reaction

Renal failure- ATN from free Hgb precipitating in renal tubules causing a mechanical obstruction DIC- Erythrocyin is released from the RBC = activates intrinsic clotting cascade Hemodynamic instability- free Hgb activates kallikrein system. Final product = bradykinin- potent vasodilator

Describe the renal changes that accompany cirrhosis

Renal hypoperfusion = decreased GFR = increased RAAS, causing sodium/water retention Hepatorenal syndrome- decreased GFR = renal failure

Describe the autonomic innervation of the kidney

Renal tubules- A2- Diuresis d/t ADH inhibition Renin release - B1- increases renin release

What happens when a nerve repolarizes?

Repolarization is the removal of the positive charges from inside the cell → accomplished by potassium efflux

How much blood flow do the kidneys receive?

The kidneys receive 20-25% of the CO 1000-1250 ml/min

Why is hypocalcemia a potential complication of thyroidectomy? -How and when does it present?

Resection of the parathyroid glands (without reimplantation) = hypocalcemia at least 6-12 hours after surgery. Most s/s are due to increased nerve/muscle irritability. -Muscle spasm = tetany -Laryngospasm -AMS -Hypotension -Prolonged QT -Paresthesias -Chvostek's sign/Trousseau's sign

What is the best indicator of ventilation during neonatal resuscitation?

Resolution of bradycardia is the best indicator of adequate ventilation.

When does respiratory control mature? That being said, how does hypoxemia affect ventilation in the newborn?

Respiratory control doesn't mature until 42-44 weeks. Before maturation- hypoxemia depresses ventilation. After maturation- hypoxemia stimulates ventilation

What are the 3 possible configurations of the voltage-gated sodium channel?

Resting- channel is closed, able to be open if the neuron depolarizes Active-Channel is open, and Na is moving along it's concentration gradient into the neuron Inactive-the channel is closed, unable to be opened (refractory)

What are *early respiratory complications* of scoliosis?

Restrictive ventilatory defect: - FEV1 and FRC decreased - FEV1/FVC ratio is normal Decreased lung volumes: - VC - TLC - RV - FRC Decreased chest wall compliance

What are the 3 ways that NE can be removed from the synaptic cleft? Which is the most important?

Reuptake into presynaptic neuron Diffusion away from synaptic cleft Reuptake by extraneural tissue *Reuptake is most important

How does pregnancy affect the oxyhemoglobin dissociation curve?

Right shift = increased P50 = facilitates O2 unloading in the fetus

What are the risk factors for postintubation laryngeal edema?

Risk factors are all related to a small airway or airway trauma. PEET CHAT HUH Prolonged intubation ETT too large ETT cuff volume too high Traumatic/multiple intubation attempts Coughing Head and neck surgery Age < 4 years Trisomy 21 Head repositioning during surgery URI possibly History of infectious or post-intubation croup

What is the MOA of sulfonylureas?

Risk of hypoglycemia Stimulate insulin release Avoid if sulfa allergy Cardiac morbidity increased in high risk patients due to closing of KATP channels and prohibiting preconditioning

An infant that is susceptible to malignant hyperthermia develops a laryngospasm during induction of anesthesia. There is no IV in place. -What is the best drug to give at this time?

Roc is the only NDNMB that can be given via IM If < 1 year = 1mg/kg If > 1 year = 1.8mg/kg

Discuss the use of the aminosteroid neuromuscular blocker in patients with chronic kidney disease.

Rocuronium primarily undergoes hepatobiliary elimination, however it is associated with an unpredictably increased DOA. Possible causes include reduced clearance, altered protein binding, and/or increased potency. Vec is metabolized to 3-OH. Its duration is prolonged as a function of decreased clearance and an increased elimination half-life Pancuronium is primarily eliminated by the kidneys

What are the 5 main components of the brachial plexus?

Roots, trunks, divisions, cords, branches

Which pediatric patient populations should receive an IVF that contains glucose?

Routine use of glucose-containing solutions is generally not recommended. These fluids should be reserved for infants and children at risk of developing hypoglycemia including: C PNC Prematurity Newborns of diabetic mothers Children with DM who have received insulin the day of surgery Children who receive glucose-based parental nutrition

Describe the MOA, clinical use, and key side effects of thiazide diuretics

Rx- HCTZ, metolazone, indapamide MOA- inhibit Na-Cl transporter in the distal tubule Clinical uses- HTN, CHF, osteoporosis (reduces Ca excretion), nephrogenic DI SE: Hyperglycemia, -calcemia & -uricemia Hypokalemic, -chloremic & -volemia Metabolic alkalosis

Describe the MOA, clinical use, and key side effects of loop diuretics

Rx- furosemide, bumetanide, ethacrynic acid MOA- Poison the Na-K-2Cl transporter in the medullary region of the thick portion of the ascending loop of Henle. The amount of sodium that remains in the tubule overwhelms the distal tubule's reabsoprtion capability- large volume of dilute urine is excreted. K, Ca, mag, Cl, are lost in urine as well. Uses- HTN, CHF, acute pulmonary edema, hypercalcemia Key SE- hypokalemic, hypochloremic metabolic alkalosis, hypocalcemia, hypomagnesemia

Describe the autonomic innervation of the bladder

Trigone/sphincter - A1 = contraction M = relaxation Detrusor - B2 = relaxation M = contraction

Describe the MOA, clinical use, and key side effects of osmotic diuretics

Rx- mannitol, glycerin, isosorbide MOA- sugars that undergo filtration but not reabsorption. They inhibit water reabsorption in the proximal tubule (primary site) as well as the loop of Henle. Water is excreted more than electrolytes. Clinical use- free radical scavenging, prevention of AKI, intracranial HTN Key SE- volume overload in CHF patients, pulmonary edema. If the BBB is disrupted, mannitol will enter the brain and cause cerebral edema.

Describe the MOA, clinical use, and key side effects of potassium-sparing diuretics.

Rx- spironolactone, amiloride, triamterene MOA- amiloride and triamterene inhibit potassium secretion and sodium reabsorption in the collecting ducts. Their function is independent of aldosterone Spironolactone exists in a subclass of K-sparing diuretics called aldosterone antagonists. By blocking aldosterone at mineralocorticoid receptors, spironolactone inhibits K secretion and soium reabsorption in the collecting ducts. Clinical uses- reduce potassium in a patient receiving a loop or thiazide diuretic SE- hyperkalemia- risk is increased with concurrent use of NSAIDs, BB and ACE-I Metabolic acidosis Gynecomastia

How do TNS symptoms present? What is the treatment?

S/s- this one causes pain. Back and Butt pain that radiates to both legs. Generally develops within 6-36 hours, and persists for 1-7 days Tx- NSAIDs, opioid analgesics, trigger point injections

How does cauda equina syndrome present? What is the treatment?

S/s: Does not have pain Bowel and bladder dysfunction Sensory deficits Weakness and/or paralysis Treatment- supportive

Where do the heart sounds match up on the left ventricular pressure loop?

S1- Closure of mitral and tricuspid valves (onset of systole) S2- Closure of aortic and pulmonic valves (onset of diastole) S3- May suggest systolic dysfunction (normal in kids and athletes) S4-May suggest diastolic dysfunction

List 5 indications for cardiac pacemaker insertion

SA node disease AV node disease Long QT syndrome Dilated cardiomyopathy Hypertrophic obstructive cardiomyopathy

Discuss the pathophysiology of RDS

SALSA Surfactant production ⬇️ = at risk for RDS. Alveoli remain stiff and noncompliant d/t ⬇️ surfactant Larger alveoli = overdistended d/t accepting volume from collapsed smaller alveoli Small alveoli tend to collapse Atelectasis = VQ mismatch

What is the treatment plan for an acute hemolytic reaction?

SAMS CSS Stop transfusion Alkalinize urine with NaHCO3 Maintain UOP >75-100ml/hr Send urine/plasma Hgb to blood bank Check PLT, PT, fibrinogen Send unused blood back to blood bank to double-check cross match Support hemodynamics with IVF/pressors

Discuss the anesthetic management of the patient who has previously undergoing Fontan completion.

SAPB Single ventricle pumps blood into the systemic circulation - 🚫 pulmonary AVOID PPV Preload dependent- do not let them get dry Blood flow into the lungs is completely dependent on negative intrathoracic pressure during spontaneous breathing

How is blood pressure affected in the patient with coarctation of the aorta?

SBP is elevated in the upper extremities SBP is lower in the lower extremities

Characteristics of SIADH

SIADH-associated with TBI, CA (small-cell lung carcinoma), noncancerous lung disease and carbamazepine Presents as hyponatremia Volume overload, hypotonic osmolarity, low plasma sodium Low UOP, high urine osmolarity, high urine NA Treatment- fluid restriction Na replacement if Na <120 mEq/L or if patient is symptomatic (do not correct faster than 1 mEq/L) Demeclocycline reduces responsiveness to ADH

List 6 risk factors for perioperative cardiac morbidity and mortality for non-cardiac surgery

SICC DS Surgery Ischemic heart disease CHF Cerebrovascular disease DM Serum creatinine > 2mg/dL

10 risk factors for difficult intubation

SIMPL MTP NP Small mouth opening Interincisor distance < 3cm Mandibular protrusion test class 3 Palate is narrow with high arch Long upper incisors Mallampati 3 or 4 TMD < 6cm or >9cm Poor AO joint mobility Neck is thick/short Poor compliance of submandibular space

Which ventilation mode guarantees a minimum Vm and is useful for weaning or with an LMA?

SIMV

What are the *CV considerations* for a patient with *Down syndrome*?

SLAM ASS COP Small mouth Large tongue AO instability (C1/C2 subluxation = avoid neck flexion) Midface hypoplasia Chronic pulmonary infection OSA Palate is narrow with a high arch ASD most common CV defect, then VSD Sevo induction = bradycardia common Subglottic stenosis- smaller ETT

Describe the airway in the patient with Trisomy 21.

SLAM COPS Small mouth Large tongue AO instability (C1/C2 subluxation = avoid neck flexion) Midface hypoplasia Chronic pulmonary infection OSA Palate is narrow with a high arch Subglottic stenosis- smaller ETT

What cardiac pathologies present a risk of hemodynamic collapse with neuraxial anesthesia?

Valve lesions with fixed stroke volume -Severe AS -Severe MS -Hypertrophic cardiomyopathy

What factors cause increased contractility?

SNS stimulation, catecholamines, calcium, digitalis, PDE-I

What are the anesthetic implications of acromegaly?

SOFT R LEGS Subglottic narrowing and vocal cord enlargement- difficult ETT placement- use a smaller tube OSA is common Facial features distorted- difficult mask ventilation Turbinate enlargement- risk of bleeding, avoid nasal airways Risk of HTN, CAD, rhythm disturbances Large tongue, teeth, and epiglottis - difficult DL Entrapment neuropathies are common Glucose intolerance Skeletal muscle weakness

3 conditions that increase renin release, give examples of each

STD SNS activation Tubuloglomerular feedback Decreased renal perfusion pressure

Describe the CV changes that accompany cirrhosis

SVR PADS SVR/BP decreases = increased CO Vasopressors response decrease RAAS increases = increase blood volume Portal HTN- increased hepatic vascular resistance = increased backpressure to proximal organs, esophageal varices = bleeding, splenomegaly = thrombocytopenia Ascites- decreased oncotic pressure, decreased protein binding, increased Vd. Draining ascites = HOTN Diastolic dysfunction SvO2 increases d/t increase in peripheral blood flow

Is succinylcholine safe to give to a patient with renal failure?

Safe in patients with renal failure who have a normal K level RF patients with an elevated K do not have an increased release, however, the normal response to succinylcholine may increase the K to a dangerous level

How do you dose NDNMB in the neonate? Why?

Same as adults on mg/kg basis ECF is larger, the NMJ is very sensitive to NDNMB. These 2 factors cancel each other out.

What s/s suggest a congenital diaphragmatic hernia?

Scaphoid abdomen and likely experience respiratory distress. Other findings: Barrel chest Cardiac displacement Fluid filled GI segments in the thorax

CREST syndrome is associated with what MS disorder?

Scleroderma C = calcinosis R = reynaud's E = esoph hypomotility S = sclerodactyly T = telangiectasia (spider veins)

What is the most common sign of LAST?

Seizures *Bupivacaine is the exception, cardiac arrest can occur before seizures

What are the CNS effects of lidocaine at 10-15 mcg/ml?

Seizures, LOC

What is the MOA of fenoldapam? Why is it used?

Selective DA1 receptor agonist that increases RBF Low dose (0.1-0.2mcg/kg/min) is a renal vasodilator and increases RBF, GFR, and facilitates Na excretion without affecting arterial BP May offer renal protection during aortic surgery and CPB

How does sensitivity to local anesthetics change in the elderly?

Sensitivity increases Decreased number and diameter of myelinated nerves, decreased conduction velocity

Which type of evoked potential is the most sensitive to the effects of volatile anesthetics? -Which is the most resistant?

Sensitivity ranking: Visual, SSEP/MEP, Brainstem, 1. Visual evoked potentials are most sensitive 2. SSEPs/MEPs are somewhere in-between 3. Brainstem evoked potentials are most resistant

List the 5 components of the autonomic reflex arc

Sensor- afferent pathway- control center- efferent pathway- Effector

Name 3 conditions that are associated with a high risk of developing DIC

Sepsis Ob complications Malignancy

What are examples of increased Co2 production?

Sepsis, overfeeding, MH, intense shivering, prolonged seizure activity, thyroid storm, burns

How do serum creatinine and creatinine clearance change in the elderly?

Serum creatinine does not change. Creatinine clearance is decreased. This is the most sensitive indicator of glomerular function in the elderly.

Discuss the potential complications of opioid reversal with naloxone

Short DOA, may be shorter than the opioid you're trying to reverse. Consider an infusion if a long-acting opioid is the cause of respiratory depression SNS stimulation- tachycardia, cardiac dysrhythmias, pulmonary edema, sudden death N/V Fetal withdrawal- can precipitate opioid withdrawal in the neonate

What is a TIPS procedure?

Shunts flow from the Portal vein to the Hepatic vein -This reduces portal pressure and minimizes back pressure on the splanchnic organs. This also decreases the likelihood of bleeding from the esophageal varies and reduces the amount of ascites *Hemorrhage is a significant risk during TIPS

Describe the pathophysiology of sickle cell anemia

Sickle cell disease is an inherited disorder that affects erythrocytes. Amino acid substitution (valine is substituted for glutamic acid) on the beta globulin chain alters RBC geometry. This affects RBC function: -Deoxygenation of HgbS leads to sickling -In severe cases, sickling causes the RBCs to clump together, which causes mechanical obstruction of the microvasculature in the vital organs and joints. This impairs tissue perfusion and causes intense pain -Sickled cells are more prone to hemolysis and removal by the spleen (lifespan = 12-17 days)

What colors will designate a cylinder as being "MRI-safe"?

Silver tank, top of tank is the color of gas it contains

What is the BUN:Creatinine ratio? What do the numbers mean?

Since BUN undergoes filtration and reabsorption and creatinine undergoes filtration but NOT reabsorption, the ratio of these substances in the blood can help us evaluate the state of hydration. The normal ratio is 10:1 A BUN:Cr ratio of >20:1 suggests prerenal azotemia Non-renal causes-trauma, sepsis, hemorrhage, hematoma, high protein diet

What is the function of the Kupffer cells?

Since portal vein blood drains the intestine, the liver receives a significant bacterial load. Kupffer cells (part of the reticuloendothelial system) removes the bacteria before the blood drains into the vena cava

Presentation of hypocalcemia

Skeletal muscle cramps Nerve irritability- paresthesia and tetany Chvostek sign Laryngospasm Mental status changes- seizures Long QT interval

In what situation can atropine cause a paradoxical bradycardia?

Small dosing - < 0.5mg

6 indications for the Bullard laryngoscope

Small mouth opening Impaired C-spine mobility Short, thick neck Treacher-Collins syndrome Pierre-Robin syndrome

How is tobacco smoke harmful?

Smoking increases SNS tone, sputum production, carboxyhemoglobin concentration and risk of infection

What drugs are used in the treatment of carcinoid crisis?

Somatostatin (octreotide) Antihistamines 5-HT3 antagonists Steroids Neo or vasopressin for hypotension

Discuss enterohepatic circulation and list 1 drug example.

Some conjugated compounds are excreted in the bile, reactivated in the intestine, and then reabsorbed into the systemic circulation Ex: diazepam

When is the *diagnosis* of *RDS* made?

Soon after birth: MINT GHH - Mixed acidosis - Inter/sub costal retractions - Nasal flaring - Tachypnea -Grunting -Hypoxemia -Hypercarbia

Describe autonomic innervation of the eye

Sphincter muscle = M = Contraction = Miosis (near vision) Radial muscle = A1 = Contraction = Mydriasis Ciliary muscle = B2 = Relaxation (far vision)

Describe the autonomic innervation of the GI tract

Sphincters: M = relaxation A1 = contraction Gallbladder and ducts: M = contraction B2 = relaxation, Motility and tone: M = ⬆️ A1/A2/B1/B2 = ⬇️, Salivary glands: M = ⬆️ A2 = ⬇️

Discuss the blood flow to the spinal cord

Spinal cord is perfused by -1 anterior spinal artery (anterior 2/3 of spinal cord) -2 posterior spinal arteries (posterior 1/3 of spinal cord) -6-8 radicular arteries

Which Mapleson circuit is the most efficient for spontaneous ventilation? -Which is best for controlled ventilation?

Spontaneous = Mapleson A Controlled- Mapleson D

AKIN AKI criteria

Stage 1 = Increased serum creatinine 50% or 0.3mg/dl UOP < 0.5ml/kg/hr x 6 hr Stage 2= increased serum creatinine 100% UOP <0.5ml/kg/hr x 12 hours Stage 3- Increased serum creatinine 200% or serum creatinine > 4mg/dL, with an acute rise of 0.5mg/dL UOP <0.3 ml/kg/hr x 24 hours or anuria x 12 hours

5 stages of CKD

Stage 1- normal - GFR >90 Stage 2- mildly decreased - GFR 60-89 ml/min Stage 3- Moderately decreased- GFR 30-59 ml/min Stage 4- Severely decreased- GFR 15-29 ml/min Stage 5- Kidney failure requiring dialysis. GFR < 15

Describe the DeBakey and Stanford classification systems of aortic dissection.

Stanford: ascending or not ascending Type A: Ascending aorta. Type B: No ascending aorta. DeBakey: Type 1: tear in ascending + dissection along ENTIRE aorta. Type 2: tear in ascending + dissection @ ascending. Type 3: Tear in proximal descending aorta 3a- dissection limited to thoracic 3b-dissection along thoracic and abdominal aorta

What is steady state? How many half lives must elapse to achieve it?

Steady state occurs when the amount of drug entering the body is equivalent to the amount of drug being eliminated from the body- there is a stable plasma concentration. - each of the compartments has equilibrated, although the total amount of drug may be different in different compartments - SS rate of administration = rate of elimination -steady state is achieved after 5 half-lives

What are the 2 primary ways a heart valve can fail?

Stenosis- fixed obstruction to forward flow during chamber systole, chamber must generate a higher than normal pressure to eject the blood Regurgitation- the valve is incompetent (its leaky), some blood flows forward and some blood flows backwards during chamber systole

What is the treatment for adrenal insufficiency?

Steroid replacement → 15-30 mg cortisol equivalent/day

What is the MOA for desmopressin? What type of vWF diseases responds best to it? What is the dose?

Stimulates the release of endogenous vWF and increases factor 8 activity. Type 1 disease respond best to desmopressin. Type 3 disease do not respond to desmopressin because they don't produce vWF. Dose is 0.3-0.5 mcg/kg IV SE- HOTN with rapid administration

6 situations that can precipitate AH

Stimulation of hollow organs - bowel, bladder or uterus Bladder catheterization Surgery- esp. cysto or colonoscopy BM Cutaneous stimulation Childbirth

Why is bacterial contamination more common in PLT than with RBC or FFP?

Stored at room temperature

What is the most common organism responsible for post-spinal bacterial meningitis?

Streptococcus viridans- commonly found in the mouth = mask during neuraxial block

Where does the subarachnoid space terminate in an adult? In an infant?

Subarachnoid space terminates at the dural sac Adult = S2. "Think Subarachnoid space is two words and only adults can say that" Infant = S3. "Infants can only say "SAB" which is three letters

Definition of secretion

Substance is transferred from the peritubular capillaries to the tubule

Discuss the use of succinylcholine in the patient with spinal cord injury.

Succinylcholine should be avoided 24 hours after injury, and should not be used for at least 6 months thereafter (some texts say 1 year)

What is the best way to prepare the skin prior to neuraxial anesthesia?

Suitable methods include chlorhexidine, isopropyl alcohol, and iodine solutions. According to Miller, best method is combo of CHG and isopropyl alcohol. CHG is neurotoxic, so it's imperative that it's allowed to dry completely before you penetrate the skin with a needle.

At the level of the ankle, which nerve is not immediately adjacent to a vascular structure?

Superficial peroneal nerve

Which component of the anesthesia machine/circuit goes with which part of the SPDD model?

Supply = cylinder Processing = vaporizer Delivery = circle system Disposal = scavenger

What is the treatment for hypermagnesemia?

Supportive Diuretics to increase Mag excretion IV calcium

What are the relative indications for one-lung ventilation?

Surgical exposure (high priority) - TPTUM Thoracic aortic aneurysm Pneumonectomy, Thoracoscopy, Upper lobectomy, Mediastinal exposure Surgical exposure (low priority) - P METS Pulmonary edema s/p CABG Middle/lower lobe lobectomy, Esophageal resection, Thoracic spine surgery Severe hypoxmie r/t lung disease

Discuss the CV effects of neuraxial anesthesia

Sympathectomy vasodilates the arterial and venous circulations, although it predominantly affects the venous capacitance vessels. Consequently, there is a reduction in venous return, CO, and BP. Volume loading with ~15ml/kg and vasopressors will minimize hypotension.

Where is vWF synthesized, and what is its function?

Synthesized by the vascular endothelium and megakaryocytes 2 functions Anchors PLT to the vessel wall at the site of vascular injury (PLT adhesion) Carries inactivated factor VIII in the plasma

How do systolic and diastolic function change in the elderly?

Systolic = no change Diastolic function decreases as a function of reduced compliance and increased wall stiffness that impairs myocardial relaxation.

What information can you learn from the ABP waveform?

Systolic BP = peak of waveform Diastolic = trough of waveform PP = peak - trough Contractility = upstroke SV= AUC Closure of aortic valve = dicrotic notch

What are the 3 determinants of flow through the LVOT?

Systolic LV volume Force of LV contraction Transmural pressure gradient

What is the difference between systolic and diastolic heart failure?

Systolic heart failure- the ventricle doesn't empty well- the hallmark of systolic heart failure is a decreased EF with an increased EDV. Volume overload commonly causes systolic dysfunction. Diastolic heart failure- ventricle doesn't fill properly- Diastolic failure occurs when the heart is unable to relax and accept the incoming volume, because ventricular compliance is reduced. The defining characteristic of diastolic dysfunction is symptomatic heart failure with a normal EF.

Order the sensitivity for detecting VAE from most to least sensitive

TEE>Doppler>ETCO2>CVP>Stethoscope

Define the lung capacities and give reference values for each

TLC- 5.8L (IRV+TV+ERV+RV) VC- 4.5L (IRV+TV+ERV) IC- 3.5L (IRV + VT) FRC- 2.3L (RV +ERV) CC- varies, RV + CV

What are the contraindications for intraoperative blood salvage?

TO SIT Topical drugs in sterile field- betadine, CHG, ABX Oncologic procedure Sickle cell disease Infected surgical site Thalassemia

Discuss the pathophysiology of TRALI

TRALI is probably caused by HLA and neutrophil antibodies present in the donor plasma Donor antibodies - neutrophil activation in lungs - endothelial injury - capillary leak - pulmonary edema - impaired gas exchange - hypoxemia- acidosis = death FFP and PLT contain the highest concentration of these antibodies

How does iodine deficiency affect T3 and T4?

TSH stimulates the iodide pump. Iodine is a substrate that the thyroid requires to synthesize T3 and T4. When iodine is not available the thyroid is unable to produce a sufficient quantity of T3 and T4

Discuss Ebstein's anomaly

TURDS R Tricuspid valve defect. TR can be severe. Usually an ASD or PFO R-L shunting occurs at the level of the atria Downward displacement of the tricuspid valve and atrialization of the RV SVT is common RVF is common in the post-op period

What is the target for non-DHPs? What is the effect?

Target = myocardium Decreases chronotropy, decreases inotropy, decreases dromotropy, decreases coronary vascular resistance

What is the target for dihydropyridines? What is the effect?

Targets VSM, causes vasodilation which decreases SVR

Describe the relevant anatomy for a popliteal block

Targets the sciatic nerve in the proximal popliteal fossa At this location, the sciatic nerve is posterior and lateral to the popliteal artery and vein, and is bordered medially by the smitendinosus and semimembranosus muscles and laterally by the biceps femoris muscle. A triangle is formed in the posterior knee with the base being the popliteal crease at the knee, and the apex formed by the convergence of the biceps femoris and semitendinosus muscles

What is the test for distinguishing *MG* from cholinergic crisis? How is it performed? How are results interpreted?

Tensilon test 1-2mg edrophonium muscle weakness worse = cholinergic crisis improved muscle strength = exacerbation of MG

-Name 4 areas where brain herniation can occur.

Tent Site Sings Tonsils Tentorium cerebelli Site of surgery or trauma (transtentorial herniation) Cingulate gyrus under the falx Cerebellar tonsils through the foramen magnum

What are the side effects of beta-2 agonists when used for tocolysis?

Terbutaline, ritodrine SE: Hypokalemia Beta-2 agonists cross the placenta = ⬆️ FHR Glycogenolysis in the liver = hyperglycemia Hyperglycemic mom = neonate post-delivery hypoglycemia.

Cell bodies of the third order neurons in the spinothalamic tract reside where?

Thalamus Reticular activating system 1st order reside in dorsal root ganglion 2nd order reside in dorsal horn of spinal cord

When is the best time to use an AEC, what can you do with it?

The AEC is a long, thin, flexible, hollow tube that maintains direct access to the airway after extubation. Most commonly used to manage extubation of difficult airway. Can also obtain ETCOs, Jet ventilate through it using adapter, or insufflate O2 with adapter

What regions of the brain are NOT protected by the BBB?

The BBB separates the CSF from the plasma. It has tight junctions that restrict passage of large molecules and ions. The BBB is not present in the CTZ, posterior pituitary gland, pineal gland, choroid plexus, and parts of the hypothalamus.

Describe the A&P of the Bezold-Jarisch reflex

The BJR decreases HR when venous return is too low. This gives an empty heart more time to fill. Treatment- restore preload with IVF or elevating legs, and increase HR (epi is best)

Describe the A&P of the Bainbridge reflex, and provide an example

The Bainbridge reflex increases HR when venous return is too high. This is beneficial because it minimizes venous congestion and promotes forward flow. Ex: Increased venous return d/t autotransfusion during childbirth

Discuss the relationship between shoulder arthroscopy, interscalene blockade, and hypotensive bradycardic episodes

The Bezold-Jarisch reflex is the proposed mechanism for hypotensive bradycardic episodes during shoulder arthroscopy with interscalene blockade. These patients are typically in the sitting or semi-upright position. S/s- bradycardia, hypotension, syncope Theory- venous pooling in LE reduces venous return. Combined effects of unloaded ventricle, SNS stimulation, and epinephrine uptake from block result in a profoundly underfilled ventricle that slows its rate to increase diastolic filling time.

Describe the "needle through needle" technique for CSE.

The CSE technique provides the dual benefit of a rapid onset of spinal anesthesia and the ability to prolong the duration of anesthesia with an indwelling epidural catheter. This technique is particularly useful in labor and delivery. The needle through the needle technique is the most common approach. The epidural space is identified with the epidural needle. A spinal needle is placed through the epidural needle, and then LA and/or opioid is injected into the intrathecal space The spinal needle is removed An epidural catheter is threaded through the epidural needle.

What is the function of CSF, and where is it located?

The CSF cushions the brain, provides buoyancy, and delivers optimal conditions for neurologic function. It is located in the Ventricles (left lateral, right lateral, 3rd and 4th) cisterns around the brain subarachnoid space in the brain and spinal cord

Discuss the fetal heart rate

The FHR is a surrogate measure of overall fetal wellbeing. It provides an indirect method to assess fetal hypoxia and acidosis. Use of this modality guides clinical decision making, so that we can minimize the risk of fetal injury and demise. Fetal oxygenation is a function of uterine and placental blood flow. The fetus responds to stress with peripheral vasoconstriction, HTN, and a baroreceptor mediated reduction in heart rate.

What principle determines which drugs will pass through the placenta? What is the formula?

The Fick principal determines which drugs can pass across the placenta Drug characteristics that favor placental transfer: -Low molecular weight < 500 daltons -High lipid solubility -Unionized -Nonpolar

How does the IABP function throughout the cardiac cycle? How does it help the patient?

The IABP is a counter pulsation device that improves myocardial oxygen supply while reducing the myocardial oxygen demand. Diastole- pump inflation augments coronary perfusion- Inflation correlates with dicrotic notch on AoBP waveform Systole-pump deflation reduces afterload and improves CO- deflation correlates with R wave on EKG

What is the mandibular protrusion test, and what values suggest an increased risk of difficult intubation?

The MPT assesses the function of the temporomandibular joint. The patient is asked to sublux the jaw, and the position of the lower incisors is compared to the position of the upper incisiors. Class 1- pt can move LI past UI and bite above lip Class 2- can align UI with LI Class 3- patient cannot move LI in line with UI- suggests increased risk of difficult intubation

Desribe the Mallampati score

The Mallampati exam assesses the oropharyngeal space. Helps to quantify the size of the tongue relative to the volume in the mouth. Mnemonic (PUSH) Class 1-pillars, uvula, soft palate, hard palate Class 2- uvula, s.p., h.p. Class 3- s.p., h.p. Class 4- h.p.

What is the safest flowmeter configuration on the anesthesia machine?

The O2 flowmeter should always be furthest to the right. The oxygen flowmeter should be positioned closest to the manifold outlet, because if a leak develops in the other flowmeters, it will not reduce the FiO2 delivered to the patient. If a leak develops in the oxygen flowmeter, all bets are off

What is the difference between a hepatic enzyme inducer and an enzyme inhibitor?

The P450 system is the most important mechanism of drug biotransformation in the body. In the liver, these enzymes reside in the smooth ER. -Inducers increase clearance -Inhibitors decrease clearance

Why does RV increase in the elderly? When does closing capacity surpass FRC supine vs standing?

The aged lung has a reduced elastic recoil, which causes it to become overfilled with gas. This process increases RV, which explains why the FRC increases as we age. Closing capacity surpasses FRC at ~ 45 years in the supine position, and ~65 years old when standing When CC>FRC, the small airways collapse during tidal breathing. This contributes to V/Q mismatch, increased anatomic dead space, and a reduction in PaO2

What is MAC-awake?

The alveolar concentration at which a patient opens his/her eyes. -0.4-0.5 during induction -as low as 0.15 MAC during recovery

What is anion gap, and what does it tell you?

The anion gap helps us determine the cause of the acidosis Anion ion gap = Major cations - Major anions Normal is 8-12 mEq/L Accumulation of acid = >14 = gap acidosis Loss of bicarb or ECF dilution = non-gap acidosis

What is the most important radicular artery? Which spinal segment does it typically enter the spinal cord?

The artery of Adamkiewicz is the most important radicular artery Along with the anterior spinal artery, the artery of Adamkiewicz supplies the anterior cord in the thoracolumbar region. Most commonly originates between T11-T12

Describe the relationship of the terminal branches relative to the axillary artery

The axillary block targets four terminal branches of the brachial plexus as they course distally with the axillary artery and vein along the humerus from the apex of the axilla. MURM 01:00 is Median 04:00 is Ulnar 08:00 is Radial 11:00 is Musculocutaneous

Where do cords turn into terminal branches?

The cords separate into the terminal branches in the axilla

What is a dermatome, and which ones are important to know as you assess a neuraxial anesthetic?

The dermatome relates to an area of skin that is innervated by a spinal nerve- not necessarily the area of skin that is in the same plane as the spinal nerve.

Describe how the respiratory muscles function during inhalation?

The diaphragm and external intercostals contract during inspiration (tidal breathing) The diaphragm increases the superior-inferior dimension of the chest The external intercostals increase the anterior-posterior diameter Accessory muscles include the sternocleidomastoid and scalene muscles

What is the difference between a strong acid and a weak acid, and a strong base and a weak base?

The difference is the degree of ionization -if you put a strong acid or strong base in water, it will ionize completely -If you put a weak acid or weak base in water, a fraction of it will be ionized, and the remaining fraction will be unionized.

Where do divisions turn into cords?

The divisions converge into cords when the brachial plexus goes under the pectoralis minor muscle

What are the implications when VD is < TBW?

The drug is assumed to be hydrophilic. It distributes into some or all of the body water, but does not distribute into fat. It will require a lower dose to achieve the given plasma concentration. Ex: NMB (ECF), albumin

How do you calculate ejection fraction

The ejection fraction is a measure of systolic function (contractility). It is the percentage of blood that is ejected from the heart during systole. (SV/EDV) x 100 Normal EF 60-70%

How do you block the ulnar nerve at the elbow?

The elbow is flexed 90 degrees and LA is injected between the olecranon and medial epicondyle of the humerus. Volume 3-5mL Using too much volume can compress the ulnar nerve, resulting in ischemic injury

What is the glycocalyx, and what factors disrupt it?

The endothelial glycocalyx forms a protective layer on the interior wall of the blood vessel. It is the gatekeeper that determines what can pass from the vessel into the interstitial space. It also contains anticoagulant properties. Disruption of the glycocalyx contributes to capillary leak. Accumulation of fluid and debris in the interstitial space reduces tissue oxygenation. Conditions that impair the integrity of the glycocalyx include: Sepsis Ischemia DM Major vascular surgery

What is Batson's plexus, and what is its significance?

The epidural veins (Batson's plexus) drain venous blood from the spinal cord. These valveless veins pass through the anterior and lateral regions of the epidural space. Obesity and pregnancy increase intra-abdominal pressure, causing engorgement of the plexus. This is associated with an increased risk of needle injury or cannulation during neuraxial techniques.

Regarding the extrinsic pathway: -What activates it? -What lab tests measure it? -What drug inhibits it?

The extrinsic pathway is activated by vascular injury (tissue trauma liberates tissue factor from the subendothelium) Measured by PT and INR Inhibited by coumadin

What are the anatomic borders of the facet joint?

The facet joint is formed by the superior articular process of one vertebra and the inferior articular process of the vertebra directly above Injury to the facet joint can compress the spinal nerve that exits the respective intervertebral foramina, causing pain and muscle spasm along the associated dermatome.

Discuss the anatomy of the femoral triangle

The femoral nerve = L2-L4. Femoral nerve stays in the groove between the psoas major and iliac muscles before entering the femoral triangle. Inside the triangle, the femoral nerve runs -deep to inguinal ligament -anterior to iliopsoas muscle -inferior to fascia lata and fascia iliaca Triangle is shaped like the "SAIL" of a ship S = sartorius A = adductor longus IL= inguinal ligament

Discuss the anatomy and innervation of the anterior and posterior branches of the femoral nerve

The femoral nerve divides into anterior and posterior branches. This occurs either just before or just after the nerve passes under the inguinal ligament Anterior branch: innervates the ventral surface of the thigh and the sartorius muscle Posterior branch: innervates quadriceps muscles, knee joint, and its medial ligament -Posterior branch gives rise to saphenous nerve

Describe the goals and strategies for mechanical ventilation in the patient with COPD?

The goal is to prevent barotrauma and to reduce air trapping. This is accomplished by: Low tidal volume (6-8ml/kg IBW), increased E time to minimize trapping, slow inspiratory flow to optimize V/Q matching, and low levels of PEEP

How does neuraxial affect GI function?

The gut receives PNS innervation from the vagus nerve, and SNS innervation from the sympathetic chain between T5-L2. Inhibition of the SNS chain allows the PNS output to the gut to function unopposed. Inhibition of SNS outflow causes sphincters to relax and increases peristalsis.

What factors affect the accuracy of the NIBP measurement?

The ideal bladder length is enough to wrap around 80% of the extremity The ideal bladder width is 40% of the circumference of the patient's arm Falsely increased- cuff too small, cuff too loose, measured below level of heart Falsely decreased- cuff too big, cuff deflated too rapidly, cuff above level of heart

Insulin receptor physiology

The insulin receptor is made up of 2 alpha and 2 beta subunits that are joined together by disulfide bonds. When insulin binds to the receptor, the beta subunits activate tyrosine kinase which then activates insulin-receptor substrates (IRS). The insulin cascade turns on the GLUT4 transporter, which increases glucose uptake by skeletal muscle and fat.

Describe the structure and function of the flow tube

The internal diameter of the flow tube is narrowest at the base and progressively widens along its ascent. The annular space is the area between the indicator float and side wall of the flow tube. Indeed, the annular space is also narrowest at the base and widest at the top. This "variable orifice" architecture provides a constant gas pressure throughout a wide range of flow rates.

Regarding the intrinsic pathway: -What activates it? -What lab tests measure it? -What drug inhibits it?

The intrinsic pathway is activated by blood injury or exposure to collagen Measured by PTT and ACT Inhibited by heparin

How does tubuloglomerular feedback affect renal autoregulation?

The juxtaglomerular apparatus is located in the distal tubule, specifically the region that passes between the afferent and efferent arterioles. Tubuloglomerular feedback about the sodium and chloride composition in the distal tubule affects arteriolar tone. In turn, this creates a negative feedback loop to maintain RBF

How does the kidney contribute to acid-base balance? What other organ is essential to this process?

The key organs of acid-base balance include the lungs and the kidneys The lungs excrete volatile acids (CO2) and the kidneys excrete non-volatile acids The kidneys maintain acid-base balance by titrating hydrogen in the tubular fluid, which creates acidic or basic urine.

How do the kidneys help to regulate blood pressure? What other systems also contribute to blood pressure regulation?

The kidneys provide intermediate and long term blood pressure control. Long term control of BP is carried out by the thirst mechanism (input) and sodium and water excretion (output) Intermediate control of BP is carried out by the RAAS Short term control is carried out by the baroreceptor reflex

What is the role of the line isolation monitor? What should you do if it alarms?

The line isolation monitor assesses the integrity of the ungrounded power system in the OR. it tells you how much current could potentially flow through you or a patient if a second fault occurs. The primary purpose is to alert the OR staff of the first fault Does not protect against shocks Will alarm when 2-5 mA of leak current is detected If the alarm sounds, the last piece of equipment that was plugged in should be unplugged

How can halogenated anesthetics cause hepatic injury? -Which agent presents the greatest risk?

The liver metabolizes desflurane, isoflurane and halothane to inorganic fluoride ions and TFA Halothane hepatitis is believed to be the result of an immune mediated reaction caused by TFA. Up to 40% of halothane is metabolized, so it makes sense that halothane metabolism produces a significant quantity of TFA. 0.02% of desflurane and 0.2% of isoflurane are metabolized. Since these drugs produce miniscule quantities of TFA, there is a theoretical risk that they can cause hepatitis in sensitized patients. Sevoflurane does not produce TFA

Describe the anatomy of the psoas compartment

The lumbar plexus is contained within a sheath inside the psoas compartment Plexus is LAP -Lateral to vertebral column -Anterior to QL muscle -Posterior to psoas muscle

What is the Child-Pugh score?

The modified Child-Pugh score examines 5 factors of hepatic function: E PABA Encephalopathy PT Albumin Bilirubin , Ascites Class A- 5-6 points- 10% risk of perioperative mortality Class B- 7-9 points = 30% risk of perioperative mortality Class C 10-15 points = 80% risk of perioperative mortality If a patient with class A or B disease is otherwise optimized, it is reasonable to proceed with surgery. A patient with class C disease should be managed medically until hepatic function improves

Discuss the relationship between blood type, erythrocyte antigens, and plasma antibodies

The most clinically important antigens are the ABO and Rh systems. If the antigen is expressed on the erythrocyte, then there will NOT be an antibody against that specific antigen in the plasma. If an antigen is NOT expressed on the RBC, then there WILL be an antibody against that specific antigen in the plasma.

What is the most common clinical finding in a patient in a patient with a subarachnoid hemorrhage? What are the other s/sx?

The most common symptom in a patient with a sAH is an intense HA that is often described as the "worst one in my life" Consciousness is lost about 50% of the time, and other s/sx include focal neurologic deficits, N/V, photophobia, and fever. Meningismus (signs of meningitis) occurs as blood spreads throughout and irritates the subarachnoid space. The blood can also block CSF flow, causing obstructive hydrocephalus and increasing ICP

Describe the anatomy of the nephron

The nephron is the functional unit in the kidney.

Which cranial nerve resides in the CNS? What is the implication of this?

The optic nerve is the only nerve surrounded by the dura. The rest of the cranial nerves are part of the peripheral nervous system.

What does the oxygen analyzer measure and where is it located?

The oxygen analyzer measures oxygen concentration (not pressure) and is the only device downstream of the flowmeters that can detect a hypoxic mixture.

Discuss the process of pain modulation

The pain signal is modified (inhibited or augmented) as it advances towards the cerebral cortex *Most important site of modulation is the substantial gelatinous in the dorsal horn -Pain is inhibited when spinal neurons release GABA and glycine, or the descending pain pathway releases NE, 5-HT, and endorphins -Pain is augmented by central sensitization and wind-up

Discuss the process of pain transmission

The pain signal is relayed through the three-neuron afferent pain pathway along the spinothalmic tract -First-order neuron: periphery → dorsal horn -Second-order neuron: dorsal horn → thalamus -Third-order neuron: thalamus → cerebral cortex

Discuss the balance of prostacyclin and thromboxane in the patient with preeclampsia.

The patient with preeclampsia produces up to 7x more thromboxane than prostacyclin. Thromboxane = Vasoconstriction, PLT aggregation, & reduced placental blood flow.

Describe the inter-incisor gap. What is normal?

The patient's ability to open the mouth directly affects your ability to align the oral, pharyngeal, and laryngeal axes. A small inter-incisor gap creates a more acute angle, and increases the difficulty of intubation. Normal 2-3 FB or 4 cm

What is the function of a phase 2 reaction? List 5 common substrates

The phase 2 reaction conjugates (adds on) an endogenous, highly polar, water soluble substrate to the molecule. This results in a water soluble, biologically inactive molecule ready for excretion. Ex: glucuronic acid, glycine, acetic acid, sulfuric acid, or a methyl group

Which approach to the brachial plexus is most likely to cause phrenic nerve paralysis? What are the clinical implications of this?

The phrenic nerve is nearly always blocked when performing an interscalene block, resulting in ipsilateral hemiparesis of the diaphragm. In patients with respiratory disease (COPD) phrenic nerve paralysis may result in severe dyspnea, hypercapnia, and hypoxemia

What are the 2 most important determinants of fluid transfer between capillaries and interstitial space?

The plasma is in direct contact with the interstitial fluid by way of pores in the capillaries. The movement of fluid between the intravascular space and interstitial space is determined by: Starling forces The glycocalyx

What determines how much blood is delivered to the portal vein?

The portal vein receives venous blood that has passed through the splanchnic circulation

Describe the subunits in the post-synaptic, nicotinic receptor at the NMJ?

The postsynaptic nicotinic receptor (Nm) is a pentameric ligand-gated ion channel located in the motor endplate at the NMJ Comprised of 5 subunits = 2 Alpha, 1 Beta, 1 Delta, and 1 Epsilon subunit

What is the difference between a phase 1 and phase 2 block? What risk factors increase the likelihood of a phase 2 block with succinylcholine?

The presence or absence of fade distinguishes between a phase 1 or phase 2 block -phase 1 = no fade -phase 2 = fade The only time succinylcholine causes fade is when it produces a phase 2 block-otherwise, succinylcholine does not produce fade. 2 situations that favor development of phase 2 block -dose >7mg/kg -30-60 minutes of continuous exposure (gtt)

What is apoptosis

The process of programmed cell death. While this is a healthy response during normal development, there are concerns that commonly used anesthetic agents can kill neurons, potentially causing neurocognitive delays later in life.

What wavelengths of light are emitted by the pulse oximeter? What law is used to make the SpO2 calculation?

The pulse oximeter is based on the Beer-Lambert law, which relates the intensity of light transmitted through a solution and the concentration of the solute within the solution 2 wavelengths Red light- 660 nm- preferentially absorbed by deoxyHgb (venous blood) Near-infrared light-940 nm- preferentially absorbed by oxyHgb- arterial blood

Discuss the significance of renal autoregulation

The purpose of autoregulation is to ensure a constant amount of blood flow is delivered to the kidneys over a wide range of arterial blood pressures. Glomerular filtration becomes pressure dependent when MAP is outside the range of autoregulation. When renal perfusion is too low, renal blood flow is increased by reducing renal vascular resistance When renal perfusion is too high, renal blood flow is reduced by increasing renal vascular resistance. There isn't a good agreement about the range of RBF autoregulation. Best is 150-180 mmHg

What does the V/Q ratio represent?

The ratio of ventilation to perfusion (minute ventilation/CO) Normal is 0.8 If >0.8- dead space <0;8 - shunt

What ligament covers the sacral hiatus? What is the significance of this?

The sacral hiatus is covered by the sacrococcygeal ligament This ligament is punctured during the caudal approach to the epidural space.

Describe the innervation of the saphenous nerve. What are the implications of this in the context of surgery on the lower extremity?

The saphenous nerve is the terminal branch of the posterior division of the femoral nerve. Provides sensory innervation from the medial aspect of the knee to the medial malleolus. There is no motor component. This block is useful when combined with a popliteal or ankle block- these don't capture the saphenous distribution.

Describe the anatomy of the sciatic nerve

The sciatic nerve arises from L4-L5 and S1-S3 Sciatic nerve is actually 2 nerves contained within a sheath (tibial and peroneal) Exits the pelvis inferior to the piriformis muscle via the great sacrosciatic foramen As it continues caudally, it passes between the major trochanter and the tuberosity of the ischium into the lower 1/3 of the thigh. This is where the sciatic nerve divides into tibial and common peroneal nerves.

Envision the anatomy of the spinal cord and spinal nerve in cross section.

The spinal cord links the peripheral nerves to the brain. Sensory neurons from the periphery via the dorsal nerve root. Motor and autonomic neurons exit via the ventral nerve root.

Setting the concentration on the vaporizer dial determines?

The splitting ratio. Setting a higher concentration directs more FGF towards the liquid anesthetic, while setting a lower concentration directs less FGF towards the liquid anesthetic.

Which approach to the brachial plexus is most likely to cause Horner's syndrome? What are the clinical implications of this?

The stellate ganglion (cervothoracic ganglion) is located at C7 Structure is often blocked during the interscalene approach, resulting in Horner's syndrome Ptosis, miosis, anhidrosis Horner's syndrome indicates a successful block

What types of surgical procedures are well suited for a supraclavicular block? Which are not?

The supraclavicular block targets the trunks/divisions of the brachial plexus Dense block for surgeries at or below the level of the elbow Not good for shoulder procedures

How does the surgical stress response affect renal blood flow?

The surgical stress response induces a transient state of vasoconstriction and sodium retention. This persists for several days, resulting in oliguria and edema. Vasoconstriction of the renal vasculature during this time predisposes the kidneys to ischemic injury and nephrotoxicity from drugs administered during the perioperative period

What is the thyromental distance and what values suggest an increased risk of difficult intubation?

The thyromental distance helps us estimate the size of the submandibular space. DL may be more difficult if the TMD is < 6cm (3fb) or >9cm

The tip of the PAC should be positioned in West lung zone _____.

The tip of the PAC should be in zone 3. In this region there is a continuous column of blood between the tip of the PAC and the LV. Since LVEDP reflects back through the pulmonary circulation, a tip positioned in zone 3 provides the most accurate estimation of LVEDP.

What is the transcellular potassium shift, and what causes it to occur?

The transcellular K+ shift describes a number of processes that alter serum K+ by shifting K+ in or out of cells Things that cause the K to shift in= alkalosis, B2 agonists, theophylline, insulin Things that cause the K to shift out= acidosis, cell lysis, hyperosmolarity, succinylcholine

What is the best treatment for vasoplegic syndrome?

Vasopressin is best, 0.5-1u IV bolus, followed by infusion of 0.03u/min Methylene blue is next best choice

What is the primary determinant of CO in the patient with heart transplant? What is the consequence of this?

The transplanted heart is severed from autonomic influence, so the HR is determined by the intrinsic rate of the SA node. These patients often have a resting tachycardia. -CO becomes dependent on preload = these patients are VERY sensitive to hypovolemia

Where do the trunks turn into divisions?

The trunks split into the divisions underneath the clavicle and over the 1st rib

Which population of stroke patient should receive a thrombolytic agent?

The type of CVA should be determined prior to treatment, because a thrombolytic agent should NOT be given to a patient hemorrhagic stroke. The patient should receive an emergent, non-contrast CT

Contrast the presentation of upper vs lower motor neuron injury

The upper motor neurons begin in the cerebral cortex and end in the ventral horn of the spinal cord, while lower motor neurons begin in the ventral horn and end at the NMJ. Upper motor neuron injury = hyperreflexia and spastic paralysis Lower motor neuron injury = impaired reflexes and flaccid paralysis

How does N2O affect the uptake of a halogenated anesthetic during induction? -What is this called?

The use of N2O during anesthetic induction will hasten the onset of a second gas. -called second gas effect

What are the 5 divisions of the spinal column, and how many vertebrae are present in each?

The vertebral column is made up of 33 vertebrae

What is the relationship between PaCO2 and CBF? What physiologic mechanism is responsible for this?

There is a linear relationship between PaCO2 and CBF the pH of the CSF around the arterioles controls cerebral vascular resistance At a PaCO2 of 40 mmHg, CBF is 50ml/100g/min

What is the risk of a neuraxial technique in the patient with intracranial HTN?

There is an increased chance of brain herniation with sudden change in CSF pressure

How does the cardiac conduction system change in the elderly?

There is fibrosis of the conduction system and loss of SA node tissue. These changes increase the incidence of dysrhythmias

How is differential blockade different with epidural anesthesia?

There is no autonomic differential blockade with epidural anesthesia Sensory block is 2-4 dermatomes higher than motor block

How do NTG and SNP affect ICP?

These are both cerebral vasodilators. By increasing CBF, they increase ICP

Can 0.9% NaCl and/or LR be used as an irrigation solution for TURP? -Why or why not?

They are highly ionized So they can conduct electricity. These fluids are CONTRAINDICATED w/ Unipolar electrocautery is used.

What are the unique anesthetic considerations for the patient with DiGeorge syndrome?

Think..Georgie Died of Hypocalcemia Hypocalcemia Infection risk if thymus is absent Tx = thymus transplant or mature T cell infusion. Transfusion of leukocyte-depleted irradiated blood is best.

What are the 2 sub-classes of barbiturates? What are examples of each?

Thiobarbiturates- sulfur molecule in the second position. Ex: thiopental and thiamylal (Notice the Ts) -Oxybarbiturates- oxygen in second position. Ex: methohexital, pentobarbital (O's)

List 3 thionamides that can be used to treat hyperthyroidism. -What is their mechanism of action?

Thionamides = propylthiouraciil (PTU), methimazole, carbimazole These agents inhibit thyroid synthesis by blocking iodine addition to the tyrosine residues on thyroglobulin. PTU also inhibits the peripheral conversion of T4 to T3. These agents require 6-7 weeks to achieve euthyroid state Only available PO, but can be crushed and given via OGT/NGT

Discuss bladder perforation that can occur during TURP?

This complication is more easily recognized in a conscious patient, especially if the sensory anesthesia isn't much >T10 Early sign: Abdominal/shoulder pain. Reduction of irrigation fluid return is a sign of bladder rupture Treatment: Supportive IVF, Pressors w/ serial H&H Emergent Suprapubic Cystostomy or possibly even ex-lap

A patient in the PACU develops a hematoma following a right endartereacotmy. Her airway is completely obstructed. What is the best treatment at this time?

This patient requires emergency decompression of the surgical site. If the surgeon isn't immediately available, this falls on you. Cricothyroidotomy may be required.

What is the treatment for cerebral vasospasm?

Triple H therapy → Hypervolemia, hypertension, and hemodilution (Hct 27-32%) Liberal hydration supports blood pressure and CPP. Hemodilution reduces blood viscosity and cerebrovascular resistance. -Nimodipine is the only CCB shown to reduce morbidity and mortality associated with vasospasm. It does not relieve the spasm, but instead increases collateral blood flow

What is the origin of the efferent SNS pathway?

Thoracolumbar- T1-L3 Cell bodies arise from the intermediolateral region of the s.c. and axons exit via the ventral nerve roots. -Preganglionic fibers usually synapse with postganglionic fibers in the 22 paired sympathetic ganglia (mass effect)

What drugs can be used to provide anticoagulation in a patient unable to receive heparin? How long must each be discontinued prior to surgery?

Thrombin inhibitors can be used to provide anticoagulation in patients unable to receive heparin Bivalirudin 2-3 hours Argatroban 4-6 hours Hirudin 8 hours Bival means two so stops for 2-3hours. Argatroban has 4 syllables and stopes from 4-6hours. Hirudin is the Highest and stops for 8 hours

What surgical procedure can reduce symptoms in patients with *MG*?

Thymetctomy - reduces circulating anti-AchR IgG

How does thyroid hormone affect MAC?

Thyroid hormone levels do NOT affect MAC. -However: -Hyperthyroidism = slower induction → higher CO -Hypothyroidism = faster induction → slower CO

What is the difference between a hypotonic and hypertonic solution?

Tonicity compares the osmolarity of a solution relative to the osmolarity of the plasma.

A patient complains of tourniquet pain when using a double cuff tourniquet under Bier block. List the sequence of deflating one of the cuffs and inflating the other cuff

Tourniquet pain typically begins ~45-60 minutes after inflation, and this is the most common reason why a patient would be unable to tolerate a procedure lasting more than 1 hour Steps 1. Inflate distal cuff 2. Deflate proximal cuff

For the patient who received a Bier block, when can you deflate the tourniquet?

Toxicity is the most significant risk for IVRA Tourniquet must remain inflated for minimum of 20 minutes

What disease process produces a fixed obstruction flow volume loop?

Tracheal stenosis

How does succinylcholine affect IOP?

Transiently increases IOP by 5-15mmHg for up to 10 minutes

What is the treatment for postintubation laryngeal edema?

Treatment aims to reduce swelling and improve airflow Cool/humidified O2 Racemic epi- 0.5 mL of 2.25% solution in 2.5mL of 0.9%NS Dexamethasone Heliox Patient should be observed for a minimum of 4 hours after racemic epi

What class of drugs is used to treat Alzheimer's disease? How do they interact with succinylcholine?

Treatment for Alzheimer's disease is palliative and aims to restore the concentration of Ach. This is accomplished with cholinesterase inhibitors such as tacrine, donepezil, rivastigmine, and galantamine. Cholinesterase inhibitors increase the DOA of succinylcholine- clinical significance is debatable.

How do you treat intraoperative MI?

Treatment should focus on interventions that make the heart slower, smaller, and better perfused. -BB to HR < 80 -Increase depth of anesthesia -vasodilators

What are unique SE of epidural triamcinolone?

Triamcinolone is commonly administered in the epidural space to treat lumbar disc disease. This drug is unique, it is associated with a higher incidence of skeletal muscle weakness. It's also more likely to cause sedation (not euphoria) and anorexia (not increased appetite)

What conditions cause a large V wave on the CVP waveform?

Tricuspid regurgitation allows a portion of the RV volume to pass through a closed but incompetent tricuspid valve during RV systole. This increases the volume/pressure in the RA = large V waves TAR Tricuspid regurg Acute increase in intravascular volume RV papillary muscle ischemia

Discuss LA allergy and cross sensitivity

True allergy is rare, but more common with esters, d/t being derivatives of para-aminobenzoic acid (PABA) No cross-sensitivity between esters and amides. If allergy to ester, avoid all other esters, but an amide is safe

List 4 tests of tubular function and give the normal values for each

Tubular function is measured by urine concentrating ability. Fractional excretion of Na (1-3%) Urine osmolality 65-1500 mOsm/L Urine sodium concentration 130-260 mEq/day Urine specific gravity 1.003-1.030

Turbulent flow is dependent on ____ according to what law?

Turbulent flow is dependent on gas density according to Graham's law

Which nerve roots give rise to each nerve of the lumbar plexus?

Two from L1 Iliohypogastric + Ilioinguinal Two from L2 Genitofemoral = L1 + L2 Lateral femoral cutaneous = L2 + L3 Two from L3 Obturator = L2+L3+L4 Femoral = L2+L3+L4

What are the extrajunctional receptors composed of?

Two types of EJR 1. 1 gamma sub for epsilon, 2 alpha, beta and delta 2. The A7 subtype consists of 5 alpha subunits Extrajunctional receptors resemble those that are present early in fetal development. Once innervation takes place, fetal nicotinic receptors are replaced by the normal adult subtype Denervation later in life allows for the return of both types of extrajunctional receptors. They are distributed at the NMJ and also throughout the sarcolemma

What is the most common cause of Type 1 DM and Type 2 DM?

Type 1 = autoimmune Type 2 = Obesity

5 names for the enzyme that metabolizes Ach.

Type 1 cholinesterase acetylcholinesterase true cholinesterase specific cholinesterase genuine cholinesterase

What is the difference between type 1 and type 2 diabetes mellitus?

Type 1- lack of insulin production Type 2- relative lack of insulin + insulin resistance

5 names for the enzyme that metabolizes succinylcholine

Type 2 cholinesterase Butyrlcholinesterase Pseudocholinesterase False cholinsterase Plasma cholinesterase

What is the prescribed prophylaxis regimen after exposure to hepatitis A, B, C

Type A - pooled gamma globulin, Hep A vaccine Type B- Hep B immunoglobulin Hep B vaccine Type C- Interferon + ribavirin

Compare and contrast type and screen and type and crossmatch in terms of what each tests for and how long each takes

Type: tests for antigens Screen: Antibodies

What are the 3 variants of pseudocholinesterase, and what is the DOA of succinylcholine for each?

Typical homozygous- Dibucaine # 70-80, DOA 5-10 minutes Heterozygous-dibucaine # 50-60, DOA 20-30min Atypical homozygous- dibucaine # 20-30, DOA 4-8 hours

The steps of NE synthesis What is the rate-limiting step?

Tyrosine (tyrosine hydroxylas) to DOPA (DOPA decarboxylase) to Dopamine (Dopamine B-hydroxylase) to NE Rate limiting step is tyrosine hydroxylase

6 risk factors for difficult supraglottic device placement

U A PILL Upper airway obstruction Altered pharyngeal anatomy Poor airway compliance Increased airway resistance Limited mouth opening Lower airway obstruction

What factors increase the specific gravity of CSF?

UHH AC Uremia High protein content Hyperglycemia Advanced age Colder temperature

Describe the presentation of each upper extremioty nerve injury Ulnar Median Radial

Ulnar = Claw Median = inability Radial = wrist drop

How does uncontrolled labor pain affect the fetus? Why?

Uncontrolled pain may result in increased maternal catecholamines- HTN- decreased uterine blood flow Maternal hyperventilation = leftward shift of oxyHgb curve = reduced delivery of O2 to the fetus.

Alcohol is cleared from the body via zero-order kinetics. How will this drug's rate of elimination change as plasma drug concentration change?

Under zero-order kinetics, a constant amount of drug is eliminated per unit time. The rate of elimination is independent of plasma drug concentration. Ex: alcohol, ASA, phenytoin, warfarin, heparin, theophylline

How does RLN injury affect the integrity of the airway?

Unilateral- no distress, hoarseness Bilateral- acute- respiratory distress due to unopposed action of cricothyroid muscles Chronic- no respiratory distress

Which regulatory agency sets the standards for compressed gas cylinders?

United States DOT

2 indications for retrograde intubation

Unstable C-spine (most common) Upper airway bleeding

Compare and contrast the variable bypass vaporizer with the injector-type vaporizer

Variable bypass- Vaporizer splits fresh gas, vaporized via flow over, automatic temperature and elevation compensation Injector- Dual circuit, fresh gas doesn't flow over VA, instead is a gas/vapor blender, vapor is injected into FGF. Electronically heated to 39C, no compensation for elevation

What does a normal pulmonary flow volume loop look like?

Upside down ice cream cone

What is included in the differential diagnosis of a low BUN? How about a high BUN?

Urea is the primary metabolite of protein metabolism in the liver Because urea undergoes filtration and reabsorption, it is a better indicator of uremic symptoms than as a measure of GFR

How does uremia affect coagulation? How can bleeding be minimized in these patients?

Uremic patients are at increased risk of bleeding. Bleeding time is a measure of PLT function. It is elevated by uremia, and is the most accurate predictor of bleeding risk. 1st line treatment is desmopressin Cryo can also help, but increases the risk of viral transmission Dialysis improves bleeding time, so it should be performed within 24 hours of surgery

What steps can be taken to prevent nephrotoxicity from radiographic contrast media

Use non-ionic iso or low osmolar contrast instead of hyperosmolar contrast Use the lowest volume of contrast that the procedure will allow. Withholding other drugs with known nephrotoxic effects IV hydration with 0.9% NaCl prior to the administration of contrast dye NaHCO3 injection or infusion N-acetylcysteine is a free radical scavenger.

What does the diffusing capacity for CO tell us? What are normal values?

Used to assess how well the lung can exchange gas. Normal is 17-25 mL/CO/min/mmHg

In what situations should ephedrine NOT be used to treat hypotension?

Uses endogenous catecholamine stores from presynaptic sympathetic nerve. Multiple doses = tachyphylaxis. -Doesn't work well when neuronal catecholamine stores are depleted (sepsis) or absent (heart transplant) -Risk of HTN crisis with MAOIs -Caution in conditions where increased HR or contractility is detrimental to hemodynamics

What is the most common cause of PPH? What are the risk factors?

Uterine atony is the most common cause of postpartum hemorrhage. Risk of atony is increased by: MMPP Multiparity Multiple gestations Polyhydramnios Polonged oxytocin infusion before surgery

What is the *VACTERL* association?

V = vertebral anomalies A = imperforate Anus C = cardiac abnormalities T = tracheoesophageal fistula E = esophageal atresia R = renal dysplasia L = limb anomalies

What are *late respiratory complications* of scoliosis?

V/Q mismatch Hypoxemia Hypercarbia (sign of impending faillure) Pulmonary HTN Reduced response to hypercapnia Cor pulmonale Cardiorespiratory failure

How does vasopressin increase BP?

V1 = intense vasoconstriction V2= increases intravascular volume by stimulating the synthesis and insertion of aquaporins into the walls of CD. Increases H2O but not NA = decreased serum osmolarity.

Describe the trigeminal innervation of the airway

V1- Opthalmic- nares and anterior 1/3 of septum V2-Maxillary- Turbinates and septum V3- Mandibular- Anterior 2/3 of tongue

What drugs can potentiate effects of NMB?

VA Abx- aminoglycosides, clindamycin, tetracycline Antidysrhythmics- verapamil, amlodipine, quinidine LA-most all Diuretics-lasix Other-dantrolene, tamoxifen, cyclosporine

What are the OSHA recommendations regarding VA exposure for healthcare workers in the OR

VA alone ≤ 2 ppm N2O alone ≤ 25 ppm VA + N2O ≤ 0.5 ppm and ≤ 25 ppm

How do halogenated agents affect evoked potentials? How about N2O?

VA produce dose-dependent effect- decrease amplitude and increase latency -N2O = more profound amplitude reduction

Compare and contrast VCV and PCV

VCV- delivers a preset tidal volume over a predetermined time. Since the tidal volume is fixed, the inspiratory pressure will vary as the patient's compliance changes. The inspiratory flow is held constant during inspiration. PCV-delivers a preset inspiratory pressure over a predetermined time. Since pressure and time are fixed, tidal volume and flow will depend on patient's lung mechanics.

What are the 4 tissue groups? How much CO does each receive?

Vessel rich group (10% of body mass) = 75% Muscle and skin (50% of body mass) = 20% Fat (20% of body mass) = 5% Vessel poor group (20% of body mass) = < 1%

List all the antidotes for warfarin. -When should each be used?

Vitamin K (10-20mg PO, IM, IV) may be used to reverse warfarin for non-emergent, minor surgical procedures. It requires 4-8 hours to restore the concentration of vitamin K dependent clotting factors in the blood. Emergent or high-risk procedures require reversal with FFP 1-2 units, recombinant factor 7a, or prothrombin complex concentrate

What conditions can cause vitamin K deficiency?

Vitamin K is a fat-soluble vitamin that requires the presence of fat and bile for absorption. It is also manufactured by bacteria in the gut. Malabsorptive diseases, impaired GI flora, and decreased bile production can impair fat absorption and therefore create vitamin K deficiency

What is an alternative relaxant option for *MG* patients during GA?

Volatile anesthetics - cause skeletal muscle relaxation by acting in ventral horn of SC

What is the primary determinant of spread for epidural anesthesia?

Volume

5 indications for dialysis

Volume overload Hyperkalemia Severe metabolic acidosis Symptomatic uremia OD with a Rx cleared by dialysis

When using a ventilator that couples FGF to Vt, what types of ventilator changes will impact tidal volume delivered to the patient?

Vt increases with lower RR, Increased I:E ratios, Increased FGF, increased bellows height Vt decreases with increased RR, lower I:E ratios, lower FGF, lower bellows height

An anesthesia machine uses fresh gas coupling. How do you determine the total tidal volume that will be delivered to this patient?

Vt total = Vt set on ventilator + FGF during inspiration - volume lost to compliance

How do you treat the patient with an intracerebral bleed who is warfarin

Warfarin can be reversed with FFP, prothrombin complex concentrate, and/or recombinant factor 7a. Vitamin K is not the best option for acute warfarin reversal

What is the dose for FFP?

Warfarin reversal 5-8 ml/kg Coagulopathy 10-20 ml/kg

What is washing, why is it used, and who does it benefit?

Washing the blood products with saline removes any remaining plasma and antigens in the donor RBCs. Prevents anaphylaxis in IgA deficient patients

What is dessication, and how does it apply to soda lime?

Water is required to facilitate the reaction of CO2 with CO2 absorbent. The granules are hydrated to 13-20% by weight. When the absorbent is devoid of water, it is said to be dessicated. In the presence of VA, desiccated soda lime increases the production of CO with des and iso, and compound A with sevo

Describe the distribution of body water

Water represents 60% of TBW = 42L TBW can be divided into: ICF = 40% of TBW- 28L ECF 20% of TBW - 14L ECV can be further divided into Interstitial fluid = 16% of TBW- 11L Plasma fluid = 4% of TBW - 3L

Class 1B MOA?

Weak depression of phase 0, shortened phase 3 repolarization Ex: Lidocaine, phenytoin

What is the pathophysiology of AO subluxation?

Weakening of Transverse Axial Ligament ➡️ Odontoid process compresses SC at level of Foramen Magnum = Paralysis

Describe the function of the ventilator spill valve in relation to using the O2 flush valve

When circuit pressure >2-4cmH2O expired gas is directed through the spill valve to the scavenger

Describe the proper placement of a lighted stylet

When the patient is supine, the trachea is anterior to the esophagus. Therefore, we can look at the quality of the light shining through the neck to determine if the tip of the device is in the esophagus or trachea When the stylet is in the trachea, there is a well-defined circumscribed glow below thyroid If stylet is in the esophagus, the light is more diffusely transilluminated

If type O- uncrossmatched blood is administered, most people may safely receive Rh-positive blood. Name 2 populations where Rh-negative blood is best.

Women of child bearing age Patient who has not received a previous transfusion

Does a *variable bypass vaporizer* account for elevation compensation?

YES

Can a pregnant patient receive IV heparin?

Yes, it does not cross the placenta.

Do patients with a history of heart transplantation require an antimuscarinic for reversal of a NDNMB?

Yes- not for the bradycardia, but for the other SE

What are the 3 zones of the adrenal cortex? What substances does each synthesize?

Zona glomerulosa = mineralcorticoids (salt) Zona fasciculata = Glucocorticoids (sugar) Zona reticularis = androgens (sex)

Define the West zones of the lung

Zone 1- PA>pa>pv- dead space, ventilation without perfusion Zone 2- Pa>PA>pv- Waterfall, normal physiology Zone 3- Pa>Pv>PA-shunt- perfusion without ventilation Zone 4- Pa>Pist>Pv>PA- pressure in the interstitial space impairs ventilation and perfusion

What is the formula for pulmonary vascular resistance? What are normal values?

[(MPAP-PAOP)/CO] x 80 Normal 150-250 dynes/sec/cm5

How do you calculate changes in plasma protein binding?

[Free drug] + [Unbound protein binding sites] ↔ [Bound drug] -If a drug is 98% bound and the bound fraction is reduced to 96%, the unbound or free fraction has increased by 100%

What is the relationship between antiphospholipid syndrome and aPTT?

aPTT is prolonged with SLE...BUT they are prone to Hypercoagulable state and Thrombosis due to the Antiphospholipid Antibodies (CVA DVT & PE) *pregnant pts w/ SLE are at higher risk*

Describe the calibration for a *variable bypass vaporizer* AND a *injector (desflurane) vaporizer*

agent specific

Ductus venosus function, location, functional + anatomic closure and adult remnants?

allows umbilical blood to bypass the liver umbilical V → IVC clamping of UC ligamentum venosus

What is the MOA for dexmedetomidine?

alpha-2 agonist- decreases cAMP-inhibits the locus coeruleus in the pons ( sedation)

What NMB can be reversed by sugammadex?

aminosteroid NDNMB roc > vec > pancuronium

How does the aortic cross clamp contribute to the risk of anterior spinal artery syndrome?

an AoXc placed above the artery of Adamkiewicz may cause ischemia to the lower portion of the anterior spinal cord. This can result in anterior spinal artery syndrome (AKA Beck's syndrome)

Complete the sentence: An acid donates _____

an acid donates H+

*Flow tube structure & fxn* Which 1 float is read in the middle?

ball

What is the *pathophysiology* of *kernicterus*?

bilurubin = byproduct of RBC breakdown anything that increases serum bilirubin can cause kernicterus - glucuronyl transferase metabolizes bilirubin - this pathway is immature at birth

Foramen Ovale function, location, functional + anatomic closure and adult remnants?

blood from RA → LA to bypass lungs to perfuse upper body (heart and brain) RA → LA LAP > RAP when clamping of UC → ↑SVR 3 days fossa ovalis Remains open in 30% of adults

The combination of Sevo and Baralyme has been implicated in what disastrous outcome?

breathing circuit fire

Why are *MG* patients prone to aspiration?

bulbar muscle weakness (mouth and throat) = difficulty handling secretions

*Hypokalemic* periodic paralysis is associated with a ________________ channelopathy.

calcium

Which ventilation mode is best for apneic patients?

controlled mandatory ventillation

What is the most common site of leaks in the breathing circuit?

circuit disconnect, usually the y-piece

What is the MOA of *dantrolene*?

classified as a muscle relaxant - halts Ca+2 release from RyR1 - prevents Ca+2 entry into myocyte, which reduces stimulus for Ca+2-induced Ca+2 release

Describe the pathophysiology of *Osteogenesis imperfecta*

connecive tissue d/o w/ autosomal dominant trait Thy BBC Thyroxine increased in > 50% of patients (inc. BMR + VO2 - - hypothermia); risk of MH is NOT increased Brittle bones Blue sclera Compliance ⬇️ d/t Kyphoscoliosis & Pectus Excavatum ➡️V/Q mismatch ➡️ Arterial Hypoxemia

What is *dystrophin*?

critical component of skeletal + cardiac muscle cells helps anchor actin + myosin to cell membrane absence of distrophin destabilizes sarcolemma during muscle contraction and increases membrane permeability

What factors increase oxygen demand?

tachycardia, HTN, SNS stimulation, increased wall tension, increased EDV, increased afterload, increased contractility

Pulmonary effects of alkalosis

decreased pulmonary vascular resistance

What is the *Cobb angle*?

describes magnitude of spinal curvature

Where is an *oxygen analyzer* located?

downstsream of flowmeters

Describe the splitting ratio of a *injector (desflurane) vaporizer*

dual circuit (fresh gas does not split)

What are some unique features of a *piston ventilator*?

electic motor compresses piston to generate positive pressure will not consume tank O2 in the event of pipeline failure require oxygen to compress bellows during mechanical ventilation

Describe the temperature compensation for a *injector (desflurane) vaporizer* What pressure is set inside the chamber?

electronically heated to 39degreesC 2atm pressure

What is 1 example of how the oxygen pressure failure device (failsafe) might permit the delivery of a hypoxic mixture.

failsafe devices checks *pressure*, not flow if there is pipeline crossover, then the pressure of the new gas will provide the pressure to defeat the failsafe, exposing pt to hypoxic mixture

What is *kernicterus*?

fetal encephalopathy

Describe the method of vaporization of a *variable bypass vaporizer*

flow over

List the 4 components of the *low pressure* system

flowmeter tubes (Thorpe tubes) vaporizers check valves (if present) common gas outlet

What is the gas pressure in the *intermediate pressure* system?

gas pressure = 50psi (if pipeline) = 45psi (if tank)

What is the gas pressure in the *high pressure* system?

gas pressure = cylinder pressure

Describe the method of vaporization of a *injector (desflurane) vaporizer*

gas/vapor blender (heat creates vapor that is injected into fresh gas)

List the 4 components of the *high pressure* system

hanger yoke yoke block w/ check valves cylinder pressure gauge cylinder pressure regulators

Define chronotropy

heart rate

What drug can be used to improve LA diffusion through tissue?

hyaluronidase

What condition must be avoided at all costs in both HYPER and HYPOkalemic periodic paralysis?

hypothermia *even w/ CPB!

In the patient with *ToF*, polycythemia is proportional to the degree of chronic _____________.

hypoxemia

How is vecuronium metabolized?

in the liver (30-40%)

Patients with *GBS* will have _____________ sensitivity to nondepolarizers

increased *REDUCE dose *Avoid Succ d/t EJRs

What is the MOST sensitive indicator of *MH*?

increased EtCO2

Describe what the typical pt w/ *Marfan syndrome* looks like

tall pectus excavatum (sunken chest) kyphoscoliosis hyperflexible joints

When the ambient temperature increases, the bi-metallic strip in a variable bypass vaporizer directs ________ FGF to the vaporizing chamber and ___________ to the bypass chamber

less to vap more to bypass *higher temp = higher VP*

How is pancuronium metabolized?

liver (10-20%)

What is a key diagnostic indicator for *tracheoesophageal fistula*?

maternal polyhydramnios

What is MAC-BAR?

minimum alveolar concentration required to block adrenergic response following a supramaximal painful stimulus. ~1.5x MAC

What are the *presenting symptoms* of *RA*?

morning stiffness that improves with activity painful, swollen, warm joints weakness, fatigue, anorexia, lymphnode enlargement in cervical, axillary, and epitrochlear regions

What opioids produce an active metabolite?

morphine and meperidine

What are the 2 most common side effects of *dantrolene*?

muscle weakness venous irritation

*Flow tube structure & fxn* What area of the flow tube is *narrowest*?

narrowest at base progressively widens along its ascent

What is the leak test for the *low pressure system*? What is the only component that should be left ON during this test?

negative pressure test perform test with each vaporizer turned on, one at a time

What are the *renal complications* of *SLE*?

nephritis w/ proteinuria

What is *ryanodex*?

newer dantrolene formulation each vial = 250mg dantrolene reconstitute in 5mL sterile water

At what point during the day are symptoms of *myasthenia gravis* worst?

weakness worse later in day or with exercise periods of rest improve symptoms

Describe the position of a *variable bypass vaporizer* AND a *injector (desflurane) vaporizer*

out of circuit

What device will be the FIRST to detect an oxygen pipeline crossover?

oxygen analyzer

What determines LA onset of action? Which drug disobeys this rule and why?

pKa determines onset of action. The closer the pKa to pH = faster onset *Chloroprocaine exception- has a high pKa, so should have slow onset. However, not very potent, so requires high dose, so because there are more molecules given, it's a rapid onset despite the high pKa

At what point during the day are symptoms of *ELS* worst?

weakness worst in morning, gets better throughout the day

List the 7 components of the *intermediate pressure* system

pipeline inlets pressure gauges ventilator power inlet oxygen pressure failure sys oxygen 2nd stage regulator oxygen flush valve flowmeter valve

What is the treatment for *GBS*?

plasmapheresis and/or IV IgG

What area of the spinal cord do SSEPs monitor?

posterior cord (dorsal column) sensory function

Which 2 congenital heart defects are associated with ventricular outflow tract obstruction?

pulmonary stenosis w/ ASD ToF

*MG* patients will have _______________ to succinylcholine.

resistance

Scoliosis creates a ______________ ventilatory defect.

restrictive

What feature on a ventilator minimizes the risk of barotrauma from the O2 flush valve?

risk is minimized by ventilators with fresh gas *decoupling*

Which receptor is defective in a patient with *malignant hyperthermia (MH)*?

ryanodine receptor *exposure to volatiles and/or succ activates the defective RYR1 which stimulates the SR to release way too much Ca+2 into the cell

Patients with *ELS* are ______________ to succinylcholine and _____________ to nondepolarizers.

sensitive to succ AND sensitive to nondepols *REDUCE doses of both

Ductus arteriosus function, location, functional + anatomic closure and adult remnants?

shunts blood from pulm trunk to aorta to perfuse lower body PA → prox descending aorta SVR > PVR (↑ PaO2 and ↓ prostaglandins from placenta) several weeks after birth ligamentum arteriosum

How does the *fail-safe device* work?

shuts off and/or proportionately reduces N20 flow if O2 pressure drops *< 20psi*

*Flow tube structure & fxn* Which 3 floats are read at the top?

skirted plumb bob nonrotating

What is the gas pressure in the *low pressure* system?

slightly above atmospheric pressure

What comorbidity is associated with *ELS*? What is the incidence?

small-cell lung carcinoma (oat cell) up to 60% of ELS pts also have oat-cell carcinoma

*Hyperkalemic* periodic paralysis is associated with a _______________ channelopathy.

sodium

What pulmonary complication is very common in the patient with *Marfan syndrome*?

spontaneous PTX

Define inotropy

strength of contraction (contractility)

What are the *nervous system complications* of *SLE*?

stroke

Definition of excretion

substance is removed from the body in the urine

Definition of reabsorption

substance is transferred from the tubule to the peritubular capillaries

What 3 things can increase the risk of contractures with *myotonic dystrophy*?

succinylcholine reversal of NMB w/ AchE (theoretical) hypothermia (shivering --> sustained contractions)

What 3 NMB cause histamine release?

succinylcholine atracurium mivacurium

Rank the IV opioids in terms of potency.

sufentanil > remifentanil = fentanyl > alfentanil > hydromorphone > morphine > meperidine **Mnemonic- superman rescued 5 american horses monday morning

What is signal transduction?

the process by which a cell converts an extracellular signal into an intracellular response

What 2 things are variable with *pressure controlled ventilation*?

tidal volume inspiratory flow

What 3 variables are fixed with *volume controlled ventilation*?

tidal volume inspiratory flow rate inspiratory time

Define *masseter muscle rigidity (MMR)*. What causes it? Is it safe to proceed with surgery if the patient displays MMR?

tight jaw CANNOT be opened spasm d/t inc. Ca+ in myoplasm assume MH until proven otherwise - abort surgery!

Define *trismus*. What causes it? Is it safe to proceed with surgery if the patient displays trismus?

tight jaw that can still be opened normal response to succ ok to proceed w/ surgery

Risk factors for aspiration pneumonitis

trauma emergency surgery pregnancy GI obstruction GERD PUD Hiatal hernia ascites difficult airway management Cricoid pressure impaired airway reflexes head injury seizures Residual NMB

Describe the splitting ratio of a *variable bypass vaporizer*

variable bypass (vaporizer splits fresh gas)

How do halogenated anesthetics produce immobility?

ventral horn of spinal cord

Describe the pathophysiology of *Duchenne muscular dystrophy (DMD)*

x-linked recessive dz results in absence of dystrophin protein EJRs to populate sarcolemma, predisposing pts to hyperkalemia after succ admin

*SLE* is more common in women or men?

young women incidence 1:1000 up to 50% of pts develop the malar "butterfly" rash

How much blood flow does the liver receive?

~30% of CO 1500mL

How does cortisol affect cardiovascular function?

⬆️ # and sensitivity of beta receptors on the myocardium Required for the vasculature to respond to the vasoconstrictive effects of catecholamines

Constriction of efferent arteriole on RBF, GFR, and filtration fraction

⬇️⬆️⬆️ Decrease RBF Increase both GFR and FF

Constriction of afferent arteriole on RBF, GFR, and filtration fraction

⬇️⬇️🚫 Decrease both RBF and GFR

Decreased plasma protein effect on RBF, GFR, and filtration fraction

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Increased plasma protein effect on RBF, GFR, and filtration fraction

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