Complete Board Review

What is the treatment of opioid induced skeletal muscle rigidity?

-Naloxone can reverse rigidity, but not a great option right before surgery -Best treatment: Paralysis and intubation

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 occur just before or after the ductus arteriosus, but in rare instances it occurs proximal to the left subclavian artery *Turner's syndrome has a high association with coarctation of the aorta

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

-Nasal and buccal routes are useful for preoperative sedation in children -3-4 mcg/kg 1 hour prior to surgery

What is Ma huang? -What are the complications of its use?

-Natural source of ephedrine -Complications → adrenergic overstimulation, HTN, CVA, seizures, death

Discuss the presentation of hypercalcemia.

-Nausea -Abdominal pain -HTN -Psychosis -Mental status changes → seizures

Discuss the consequences of an epidural that is placed in the subdural space.

-Neither catheter aspiration or test dose will rule out subdural placement -Within 10-25 minutes after the epidural is dosed, the patient will experience symptoms of an excessive cephalic spread of LA -It will resemble a high spinal

What is the dose for IM succinylcholine? -Which IM site has the fastest onset of action?

-Neonates and infants → 5 mg/kg -Older children → 4 mg/kg -Intralingual administration via the submental approach has the fastest onset

Contrast neostigmine reversal in adults and children.

-Neostigmine reversal is faster in children and infants

In what situations should ephedrine NOT be used to treat hypotension?

-Neural catecholamine stores are depleted (sepsis) or absent (heart transplant) -Risk of hypertensive crisis in patients on MAO inhibitors -Conditions where increased HR or contractility can be detrimental

How can you differentiate neurogenic shock from hypovolemic shock?

-Neurogenic shock → bradycardia, hypotension, hypothermia with pink, warm extremities -Hypovolemic shock → tachycardia, hypotension, cool, clammy extremities

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

-Neurotoxicity is the result of exposure to high concentrations of local anesthetic Factors that increase risk -5% lidocaine and spinal micro catheters -Microcatheters focus local anesthetic on a small area of the cord, exposing this region to a high concentration of LA

What are the functions of the 5 types of white blood cells?

-Neutrophils (60%) - Fight bacterial and fungal infection -Basophils - Essential component of hypersensitivity reactions. Release histamine, serotonin, herparin, bradykinin -Eosinophils - Defend against parasites -Monosites - Phagocytosis, release cytokines, present pieces of pathogens to T-lymphocytes -Lymphocytes - B -lymphocytes (humoral immunity) and T-lymphocytes (cell-mediated immunity)

List 3 safety relief devices that prevent a cylinder from exploding when the ambient temperature increases.

-Never expose gas cylinders to temperatures > 130 degrees F. 1. Fusible plug made of Wood's metal 2. Frangible disk that ruptures under pressure 3. Valve that opens at elevated pressures

Is it ever safe to use an oxygen cylinder in the MRI suite?

-Never, unless it is MRI safe and made of a nonmagnetic material such as aluminum

List the 3 types of cholinergic receptors. -Where are each of these found inside the body?

-Nicotinic type M (muscle): Found in the neuromuscular junction -Nicotinic type N (nerve): Found in preganglionic fibers at the autonomic ganglia (SNS & PNS) and in the CNS -Muscarinic: Found in the postganglionic PNS fibers at effector organs and in the CNS

Compare and contrast the glucocorticoid and mineralocorticoid potencies of the endogenous and synthetic steroids.

-No glucocorticoid effects = Aldosterone -No mineralocorticoid effects = dexamethasone, betamethasone, triamcinolone

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

Can 0.9% NaCl and/or LR be used as an irrigation solution for TURP? -Why or why not?

-Nope, they're highly ionized so they're good conductors of electricity. -They are contraindicated when unipolar electrocautery is used, but are allowed with bipolar electrocautery

What is the normal ACT? -What value should be achieved prior to transitioning to CPB?

-Normal ACT → 90-120 seconds -ACT should be > 400 before initiation of CPB -ACT is measured before heparin administration, 3 minutes after it's given, and every 30 minutes thereafter

When do GFR and renal tubular function achieve full maturity?

-Normal GFR is reached at 8-24 months of age -Normal tubular function is reached at 2 years of age

What is the normal intracranial pressure? -What values are considered abnormal?

-Normal ICP = 5-15 mmHg -Cerebral hypertension occurs if ICP > 20 mmHg

How do you interpret the results of the dibucaine test?

-Normal test → A normal dibucaine number is 80. This means that dibucaine has inhibited 80% of the pseudocholinesterase in the sample and suggest that the normal enzyme is present -Abnormal test → Dibucaine does not inhibit atypical plasma cholinesterase. If the patient has a dibucaine number of 20, this means that dibucaine did not inhibit the patients plasma cholinesterase and an atypical variant is present

What is the normal value for platelets? -What are the critical values?

-Normal → 150,000 - 300,000 mm3 -< 50,000 mm3 increases surgical bleeding risks -< 20,000 mm3 increases spontaneous bleeding risks

What is the active metabolite of meperidine and why is it a problem?

-Normeperidine reduces the seizure threshold and increase CNS excitability -Impaired renal function → decreased normeperidine excretion → seizures

State the equation and normal value for oxygen carrying capacity.

-O2 Carrying Capacity (CaO2) - How much O2 is carried in the blood -CaO2 = (1.34 x Hgb x SaO2) + (PaO2 x .003) -Normal = 20 mL O2/dL

When is hypothermia a good thing?

-O2 consumption is reduced by 5-7% for every 1 degree C reduction in body temperature -Cerebral ischemia -Cerebral aneurysm clipping -TBI -Cardiopulmonary bypass -Cardiac arrest -Aortic cross clamping -Carotid endarterectomy

Pressing the oxygen flush valve exposes the breathing circuit to _____ O2 flow and _____ O2 pressure.

-O2 flow = 35-75 L/min -O2 pressure = 50 psi (pipeline pressure)

What is the safest flowmeter configuration on the anesthesia machine?

-O2 flowmeter should always be the furthest to the right - closest to the manifold outlet -If a leak develops in any other flowmeter, it won't reduce the FiO2 delivered to the patient

Discuss the pathophysiology of obstructive sleep apnea.

-OSA → The cessation of airflow for at least 10 seconds with 5 or more unsuccessful efforts to breathe (obstruction) and a greater than 4% reduction in SaO2

How does obesity affect respiratory gas tensions?

-Obese patients have increased O2 consumption and increased CO2 production → minute ventilation must be increased -PaCO2 is usually normal, an elevated PaCO2 signals impending respiratory failure

Does a morbidly obese patient require a rapid sequence intubation? -Why or why not?

-Obesity alone does not mandate an RSI -Patients with other risk factors → GERD, diabetes, difficult airway → candidates for aspiration prophylaxis and/or RSI

What is post renal injury? -What is the treatment?

-Obstruction → The source of obstruction can arise anywhere between the collecting system and the urethra Treatment -Relieve the obstruction

What are the diagnostic criteria for TRALI?

-Onset < 6 hours following transfusion -Bilateral infiltrates on frontal CXR -PaO2/FiO2 < 300 mmHg or SpO2 < 90% on RA -Normal PAOP

What is the best location to assess the onset of neuromuscular blockade? -How about recovery?

-Onset is measured at the orbiculares oculi muscle with the facial nerve -Recovery is measured at the adductor pollicis muscle with the ulnar nerve

What is the onset, duration, and clearance mechanism for ketamine?

-Onset: IV = 30-60 seconds, IM = 2-4 minutes, PO = variable -Duration: 10-20 minutes (may require 60-90 minutes to return to full orientation) -Clearance: Liver (P450 enzymes) -It produces an active metabolite - norketamine -Chronic ketamine use induces liver enzymes

What is the difference between open and closed angle glaucoma?

-Open angle is caused by sclerosis of the trabecular meshwork, this impairs aqueous humor drainage -Closed angle glaucoma is caused by a closure of the anterior chamber, this creates a mechanical outflow obstruction

Discuss the use of Sch in the patient with renal failure.

-Opening of the nicotinic acetylcholine receptor can increase serum K+ by 0.5-1.0 mEq/L for up to 10-15 minutes -Sch is safe in patients with renal failure and a normal K+ level. -In the patient with hyperkalemia, Sch may increase K+ to a dangerous level

Discuss damping and the interpretation of the high pressure flush test.

-Optimally damped system → baseline is re-established after 1 oscillation -Under-damped system → Baseline is re-established after several oscillations = SBP is overestimated, DBP is underestimated, MAP is accurate -Over-damped system → Baseline is re-established after 0 oscillations = SBP is underestimated, DBP is overestimated, MAP is accurate

What's the difference between osmolarity and osmolality?

-Osmolarity → the number of osmoles per liter of solvent -Osmolality → the number of osmoses per kg of solvent

What is the difference between osmosis and diffusion?

-Osmosis → Net movement of water across a semipermeable membrane, where the direction of the water movement is driven by the difference in solute concentration on either side of the membrane (only the solvent moves) -Diffusion: Net movement of molecules from a region of high concentration to a region of low concentration (solvent and solute moves)

What are the 3 zones of the adrenal cortex? -What substances does each synthesize?

-Outside to inside → GFR release salt, sugar, sex

State the equation and normal value for oxygen delivery.

-Oxygen Delivery (DO2) - How much O2 is delivered to the tissues -DO2 = CaO2 x Cardiac output x 10 -Normal = 1000 mL O2/min

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 RR than it is to increase Vt, this is why newborns have a high RR

What clinical situations increase ADH release?

-PEEP -Positive-pressure ventilation -Hypotension -Hemorrhage

What is the dose for PRBC, FFP, platelets, and cryo for adults?

-PRBC → 1 unit increases Hgb by 1 g/dL -FFP → warfarin reversal = 5-8 mL/kg, coagulopathy = 10-20 mL/kg increases factor concentration by 20-30% -Platelets → 1 pack per 10 kg -Cryo → 5 bag pool increases fibrinogen by 50 mg/dL

What lab results are consistent with DIC (PT/INR, D-dimer, platelets, fibrinogen)?

-PT → increased -PTT → increased -D-dimer → increased -Platelets → decreased -Fibrinogen → decreased

List 3 thionamides that can be used to treat hyperthyroidism. -What is their mechanism of action?

-PTU, methimazole, carbimazole -These agents inhibit thyroid synthesis by blocking iodine addition to the tyrosine resides on thyroglobulin. PTU also inhibits the peripheral conversion of T4 to T3 -Only available PO, require 6-7 weeks to achieve a euthyroid state

List the triggers that cause sickling of HgbS.

-Pain -Hypothermia -Hypoxemia -Acidosis -Dehydration

Which neuromuscular blocker should be avoided in the patient with hypertrophic cardiomyopathy?

-Pancuronium (vagolytic effect), atracurium (histamine release), or mivacurium (histamine release)

Which neuromuscular blocker has a vagolytic effect?

-Pancuronium is unique in that it has a vagolytic effect -It inhibits M2 receptors at the SA node, stimulates the release of catecholamines, and inhibits catecholamine reuptake → Increased HR and CO

What is intrinsic renal injury? -What is the treatment?

-Parenchymal → ATN is usually caused by ischemia (medulla is at the highest risk) or nephrotoxic drugs (IV contrast dye, abx, NSAIDs) Treatment -Restore renal perfusion -Supportive

List 2 contraindications for metoclopramide.

-Parkinsons disease → dopamine antagonist effect -Bowel obstruction → prokinetic agent effect

What are the risk factors for placental abruption? -How does it present?

-Partial or complete separation of the placenta from the uterine wall prior to delivery. It results in hemorrhage and fetal hypoxia Risk factors -PIH -Preeclampsia -Chronic HTN -Cocaine use -Smoking -Excessive alcohol use *Painful vaginal bleeding

In which patient will the onset of sevoflurane be the fastest? Patient A has a heart rate of 55 ppm with a stroke volume of 100 mL/beat. Patient B has a heart rate of 60 ppm and a stroke volume of 85 mL/beat (all other factors are equal)?

-Patient B → slower CO

Which population of stroke patients should receive a throbolytic agent?

-Patient should first receive an emergent non-contrast CT -If treatment can begin < 3 hours after the onset of symptoms → patient should receive TPA -Aspirin is an acceptable alternative if TPA cannot be administered

What is the relationship between SLE and antiphospholipid syndrome?

-Patients with SLE are prone to developing antiphospholipid antibodies. Although the aPTT is prolonged, these patients are prone to a state of hypercoagulability and thrombosis. -They are at risk for stroke, DVT, and pulmonary embolism

Name two patient populations who are at increased risk for developing methemoglobinemia.

-Patients with glucose-6-phosphate reductase deficiency will need exchange transfusion -Neonates are at higher risk for toxicity

What is the rate of seroconversion following exposure to HIV infected blood?

-Percutanous injury (needle-stick) = 0.3% -Mucus membrane exposure = 0.09%

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

-Pharmacokinetics: "What the body does to the drug." It explains the relationship between the dose that you administer and the drug's plasma concentration over time. It is affected by absorption, distribution, metabolism, and elimination -Pharmacobiophysics: Considers the drug's concentration in the plasma and the effect site (biophase) -Pharmacodynamics: "What the drug does to the body." It explains the relationship between the effect site concentration and the clinical effect.

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 depolarization → K+ efflux & Cl- influx -Phase 2: Plateau → Ca+2 influx -Phase 3: Repolarization → K+ efflux -Phase 4: Na+/K+ pump restores RMP

What is the function of a phase 1 reaction? -List 3 examples.

-Phase 1 reactions result in small molecular changes that increase the polarity (water solubility) of a molecule to prepare it for a phase 2 reaction 3 phase I reactions we need to understand: 1. Oxidation - Adds an oxygen molecule to a compound 2. Reduction - Adds electrons to a compound 3. Hydrolysis - Adds water to a compound to split it apart

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+2 influx occurs at the very end of phase 4) -Phase 0: Depolarization → Ca+2 influx -Phase 3: Repolarization → K+ efflux

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

What is the difference between a phase I and phase II block? -What risk factors increase the likelihood of a phase II block with succinylcholine?

-Phase I block = No fade -Phase II block = Fade -Phase II block with Sch -Dose 7-10 mg/kg -30-60 minutes of continuous exposure (IV infusion) -Do not reverse a phase II block with Sch, wait it out!

List 3 alpha antagonists. -What is the MOA of each?

-Phenoxybenzamine: Long acting, non-selective, noncompetitive antagonists of the alpha-1 and alpha-2 receptors -Phentolamine: Short acting, non-selective, competitive antagonist of the alpha-1 and alpha-2 receptor -Prazosin: Selective alpha-1 antagonist

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

-Placenta accreta → attaches to the surface of the myometrium -Placenta increta → invades the myometrium -Placenta percreta → extends beyond the uterus -Uterine contractility is impaired and there is a potential for tremendous blood loss. Neuraxial is safe, but GA is preferred

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

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

-Plasma osmolarity is normally 280-290 mOsm/L -The 3 most important determinants are sodium (most important), glucose, and BUN

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

List 6 drugs that are selective for the beta-1 receptor.

-Pneumonic* - MABE-AB -Metoprolol -Atenolol -Betaxolol -Esmolol -Acebutolol -Bisoprolol

How is Poiseuille's law related to Ohm's law?

-Poiseuille's law is a modification of Ohm's law that incorporates vessel diameter, viscosity, and tube length -Blood flow = πR^4ΔP/8nl -R = radius -P = arteriovenous pressure gradient n = viscosità -l = length

What is the definitive test for OSA? -What does it measure? -How do you interpret the findings?

-Polysomnography → the results of this test allows for the calculation of the apnea-hypopnea index (AHI), which is used to determine the severity of OSA -Mild = 5-15 episodes/hr -Moderate = 15-30 episodes/hr -Severe = > 30 episodes/hr

In which regions of the brain do halogenated anesthetics produce autonomic modulation?

-Pons -Medulla

Which vessels supply blood to the liver? -Which provides comparatively more blood flow? -Which provides more oxygen?

-Portal vein and hepatic artery -Aorta → splanchnic organs → portal vein → liver -Aorta → hepatic artery → liver -Portal vein supplies 75% of liver blood flow and 50% of oxygen content -Hepatic artery supplies 25% of liver blood flow and 50% of oxygen content

What is the significance of the NBG pacemaker identification code?

-Position I = Chamber paced -Position II = Chamber sensed -Position III = Response to sensed event -Position IV = Programmability -Position V = Pacemaker can pace multiple sites

What factors influence FRC?

-Positioning -Anesthetic induction -NMB's -Surgical displacement -Obesity/Pregnancy

What are the potential side effects of flumazenil?

-Post operative benzodiazepine reversal does NOT increase SNS tone or anxiety -Flumazenil reversal can precipitate signs of withdrawal in benzodiazepine-dependent patients

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

Where is the posterior tibial nerve blocked?

-Posterior to the medial malleolus

Contrast the treatment of postoperative delirium and postoperative cognitive dysfunction.

-Postop delirium → treat underlying cause, antipsychotics, minimize polypharmacy -POCD → no specific treatment, most cases tend to resolve after 3 months *To minimize the risk of either condition, use rapidly metabolized drugs

Contrast the onset of postoperative delirium and postoperative cognitive dysfunction.

-Postop delirium: Early post period -POCD: Weeks to months after surgery

Discuss the relationship between remifentanil and opioid induced hyperalgesia. -What drugs can prevent this phenomenon?

-Postoperative opioid requirements are particularly high in these patients -OIH can be prevented with ketamine or magnesium sulfate

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 the precursors of the endogenous opioids?

-Pre-proopiomelanocortin → Endorphins (Mu receptor) -Pre-enkephalin → Enkephalins (Delta receptor) -Pre-dynorphin → Dynorphins (Kappa receptor)

What are contraindications to radioactive iodine?

-Pregnancy and breastfeeding mothers

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

-Prejunctional Nn receptor: Present at the presynaptic nerve → Regulates Ach release -Postsynaptic Nm receptor: Present at the motor end plate on the muscle cell → Responds to Ach

Define premature delivery and list the potential complications from its occurrence.

-Premature delivery is defined as delivery before 37 weeks gestation -It is the leading cause of perinatal morbidity and mortality, risk is even higher for newborns weighing < 1500g -Incidence of prematurity rises with multiple gestations and premature ROM Complications of premature delivery -Respiratory distress syndrome -Intraventricular hemorrhage -NEC -Hypoglycemia -Hypocalcemia -Hyperbilirubinemia

What are the risk factors for ROP?

-Prematurity -Low birth weight -Hyperoxia

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

-Prepared as a 1% solution in an emulsion of egg lecithin, soybean oil, and glycerol -Nothing to worry about, most people allergic to eggs are allergic to the albumin in eggs whites. Egg lecithin is derived from the yolk

Describe the presentation of a radial nerve injury.

-Presentation = Wrist drop, inability to extend the hand at the wrist

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

-Presents as nightmares and hallucinations (risk persists up to 24 hours) -Benzodiazepines are the most effective way to prevent emergence delirium (midazolam > diazepam) Risk Factors: -Age > 15 years -Female -Ketamine dose > 2 mg/kg -Hx of personality disorder

Define pressure.

-Pressure = Force/Area

How can the risk of succinylcholine induced myalgia be reduced?

-Pretreatment with non-depolarizing neuromuscular blocker -NSAIDS, lidocaine 1.5 mg/kg -Higher rather than lower dose of Sch *Opioids do not reduce the incidence of myalgia

Name the two local anesthetics that are most likely to produce a leftward shift of the oxyhemoglobin dissociation curve. -Why does this happen?

-Prilocaine and benzocaine → methemoglobinemia -O2 biding site on the heme portion of the Hgb molecule contains an iron molecule in its ferrous form -Oxidation of this iron molecule creates methemoglobin -Methemoglobin impairs O2 binding and unbinding from the Hgb molecule → shifting the oxyhemoglobin dissociation curve to the left

What's the difference between primary and secondary HTN?

-Primary (essential) HTN: More common - 95% of cases, has no identifiable cause -Secondary HTN: Caused by some other pathology - 5% of cases

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 types of surgical procedures are well suited for an interscalene block? -Which are not?

-Procedures involving the shoulder and proximal upper extremity -It is not the best option for procedures below the level of the elbow, as it frequently spares roots C8-T1 (lower trunk). This region innervates portions of the forearm and hand

What are the common characteristics of the opioid partial agonists?

-Produce analgesia without the risk of respiratory depression -Have a ceiling effect -Reduce the efficacy of previously administered full-agonists -Can cause opioid withdrawal in an opioid dependent patient

What conditions cause an increased a wave on the CVP waveform?

-Produced when the atria contract and empties against a high resistance -Tricuspid stenosis -Diastolic dysfunction -Myocardial ischemia -Chronic lung disease leading to RV hypertrophy -AV dissociation -Junctional rhythm -V-pacing -PVC's

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

Which positions increase the risk of post-operative airway edema and how can you assess the severity of this complication?

-Prone and Trendelenburg: Increased hydrostatic pressure → edema formation -Sitting: Neck flexion impairs venous drainage from the head → edema formation If you have a concern about the potency of the airway -Perform a leak test to assess for air movement around the ETT -Visually inspect the larynx with direct laryngoscopy

Discuss the antipruritic and antiemetic effects of propofol.

-Propofol (10 mg IV) can reduce itching caused by spinal opioids and cholestasis -Propofol (10-20 mg IV or infusion of 10 mcg/kg/min) can be used to treat PONV

What are the risk factors for propofol infusion syndrome?

-Propofol dose > 4 mg/kg/hr (67 mcg/kg/min) -Propofol infusion duration > 48 hours -Children > Adults -Inadequate oxygen delivery -Sepsis -Significant cerebral injury

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

-Propofol supports bacterial and fungal growth -Syringe → Discarded in 6 hours -Infusion → Discarded in 12 hours (including tubing)

List 3 mechanisms that promote renal vasodilation.

-Prostaglandins (inhibited by NSAIDs) -Atrial natriuretic peptide (increased RAP → Na+ and water excretion) -Dopamine-1 receptor stimulation (increased RBF)

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, it helps it do its job. -A deficiency of protein C or S can produce a hypercoagulable state, increasing the risk of thrombosis -Treatment → A thromboembolism is treated with heparin that is transitioned to warfarin

What factors determine local anesthetic duration of action?

-Protein binding is the primary determinant of duration of action -After LA injection, some of the molecules penetrate the epineurium, some defuse into circulation, and some bind to tissue proteins. Those that bind to tissue proteins serve as a reservoir that extends the duration of action -Lipid solubility and intrinsic vasodilating activity are secondary determinants of duration of action -Higher degree of lipid solubility → longer duration of action -Intrinsic vasodilating activity → increased rate of vascular uptake and shortened duration of action

What types of surgical procedures are well suited for an axillary block? -Which are not?

-Provides anesthesia to procedures distal to the elbow, not recommended for procedures proximal to the elbow

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 are the 4 most important side effects of neuraxial opioids? -Which is most common?

-Pruritus (most common side effect) -Respiratory depression (hydrophilic drugs are higher risk d/t greater rostral spread) -Urinary retention -N/V

Which acetylcholinesterase inhibitors pass through the blood brain barrier? -Which do not? Why?

-Psysostigmine 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

What lab results are consistent with hemophilia A (PT/INR, Ptt, platelet count, bleeding time, fibrinogen)?

-Ptt is prolonged because factor VIII is part of the intrinsic pathway

What are the side effects of magnesium?

-Pulmonary edema -Hypotension -Skeletal muscle weakness -CNS depression -Reduced responsiveness to ephedrine and phenylephrine

In addition to local anesthetic toxicity, what are other potential complications of a large volume of tumescent anesthesia?

-Pulmonary edema as a result of volume overload -General anesthesia is recommended if > 2-3 L of tumescent solution is injected

Define pulmonary hypertension and discuss the goals of anesthetic management.

-Pulmonary hypertension = Mean PAP > 25 mmHg -Causes: COPD, left sided heart disease -Goals: Optimize PVR

Describe the ventilatory management of the patient with a congenital diaphragmatic hernia.

-Pulmonary hypoplasia will be present, keep PIP < 25-30 cmH20 to minimize barotrauma -This may require permissive hypercapnia, this is the lesser of two evils -Abdominal closure may increase PIP, a pulse oximeter placed on the lower extremity can warn you of increased intra-abdominal pressure

How can you tell the difference between cholinergic crisis and myasthenic crisis?

-Pyridostigmine is the first-line treatment for myasthenia gravis -Administer 1-2 mg IV edrophonium (Tenilon test) -Muscle weakness is worse → cholinergic crisis → treat with anticholinergic -Muscle weakness improves → myasthenia gravis → treat with anticholinesterase and immunosuppression

What is the equation for mixed venous oxygen saturation?

-Q = CO -VO2 = O2 consumption -Hgb = Hemoglobin -SaO2 = Loading of hgb in arterial blood -Normal → 65-70%

Discuss the pathophysiology of rheumatoid arthritis.

-RA is an autoimmune disease that targets the synovial joints. There is also widespread systemic involvement due to infiltration of immune complexes into the small and medium arteries leading to vasculitis. Cytokines play a central role in the pathogenesis of RA. -The hallmark of RA is morning stiffness that generally improves with activity. The joints are painful, swollen, and warm -Other S/Sx → Weakness, fatigue, anorexia, lymph node enlargement -2-3x more common in women

What is the indication to transfuse packed red blood cells?

-RBCs are transfused to increase CaO2 -Hgb > 10 g/dL → Transfusion rarely required -Hgb < 6 g/dL → Transfusion often required -Decision to transfuse is guided by patient factors

Discuss recurrent laryngeal nerve injury in the context of thyroidectomy.

-RLN innervates all of the intrinsic laryngeal muscles except for the cricothyroid muscle (SLN) -Unilateral injury → hoarseness -Bilateral injury → airway obstruction -Have the patient say the letter "E" or "moon" to assess for nerve injury

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 mechanisms of heat transfer? -Rank them from most to least important.

-Radiation (Infrared) → 60% -Convection (Air) → 15-30% -Evaporation (Water loss) → 20% -Conduction (Contact) → <5%

What does the V/Q ratio represent? -What is the normal V/Q ratio? What do the abnormal values tell us?

-Ratio of perfusion to ventilation (minute ventilation/cardiac output) -Normal V/Q ratio is 0.8 -V/Q ratio > 0.8 = dead space -V/Q ratio of < 0.8 = shunt

Define reabsorption, secretion, and excretion.

-Reabsorption: Substance is transferred from the tubule to the peritubular capillaries -Secretion: Substance is transferred from the peritubular capillaries to the tubule -Excretion: Substance is removed from the body in the urine

What is the role of recombinant factor 7 in the management of hemophilia A and B?

-Recombinant factor 7 is a "bypass" agent because it skips over factor 8 or 9 in patients with inhibitors -Dose = 90-120 mcg/kg -Can increase the risk of arterial thrombosis as well as venous thrombosis

What wavelengths of light are emitted by the pulse oximeter? -What law is used to make the SpO2 calculation?

-Red light (660 nm) → absorbed by deoxyhemoglobin -Near-infrared light (940 nm) → absorbed by oxyhemoglobin -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

Describe the presentation of median nerve injury.

-Reduced sensation of palmar surface of the thumb, index finger, middle finger, and lateral aspect of the ring finger -Unable to oppose the thumb (chronic injury can lead to the ape hand deformity)

What is the clinical presentation of propofol infusion syndrome?

-Refractory bradycardia → asystole and one of the following: -Metabolic acidosis -Rhabdomyolysis -Enlarged or fatty liver -Renal failure -Hyperlipidemia -Lipemia (cloudy plasma or blood) → early sign

Discuss the anatomy of the renal cortex and medulla.

-Renal Cortex: Outer part of the kidney → contains most parts of the nephron (glomerulus, Bowman's capsule, proximal tubules, distal tubules) -Renal medulla: Inner part of the kidney → contains the parts of the nephron not in the renal cortex (loops of Henle and collecting ducts) -The medulla is divided into pyramids, the apex of each pyramid is called the papilla

Discuss the significance of renal autoregulation.

-Renal autoregulation is present with a MAP of 50-180 mmHg -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 decreased by increasing renal vascular resistance

How much of the renal blood flow is filtered at the glomerulus? -Where does the rest go?

-Renal blood flow = 1000-1250 mL/min -Glomerular filtration rate = 125 mL/min or 20% of RBF -Filtration fraction is 20% → 20% is filtered by the glomerulus 80% is delivered to the peritubular capillaries

Discuss the complications of an acute hemolytic reaction.

-Renal failure - acute tubular necrosis -Disseminated intravascular coagulation -Hemodynamic instability

How does renal failure affect the dosing of acetylcholinesterase inhibitors after an aminosteroid neuromuscular blocker is administered?

-Renal failure prolongs the duration of action for both AchE and aminosteroidal neuromuscular blockers -No need to adjust dose of AchE inhibitor

Describe the renal changes that accompany cirrhosis.

-Renal hypoperfusion → decreased GFR → increased RAAS → Na+ and water retention -Hepatorenal syndrome → decreased GFR → renal failure (liver transplant is definitive treatment)

What ratio should be used to replace blood loss with crystalloid, colloid, and blood?

-Replace with crystalloid at 3:1 ratio -Replace with colloid at 1:1 ratio -Replace with blood at 1:1 ratio

Why is hypocalcemia a potential complication of thyroidectomy? -How and when does it present?

-Resection of parathyroid glands → hypocalcemia at least 6-12 hours after surgery -Muscle spasm -Laryngospasm -Mental status changes -Hypotension -Prolonged QT -Paresthesias -Chvostek's sign → tapping on the angle of the jaw → facial contraction -Trousseau's sign → muscle spasm in hand or forum in response to BP cuff inflation for 3 minutes

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

How does hypoxemia affect ventilation in the newborn?

-Respiratory control don't mature until 42-44 weeks -Before maturation → hypoxemia depresses ventilation -After maturation → hypoxemia stimulates ventilation

What physiologic changes accompany tourniquet deflation?

-Restores blood flow to the extremity, producing a relative decrease in the circulating blood volume -Products of cellular hypoxia enter the systemic circulation Releasing the tourniquet → -Increased EtCO2 -Decreased temperature -Decreased BP -Decreased SvO2 -Metabolic acidosis

Describe the pulmonary changes that accompany cirrhosis.

-Restrictive defect: Ascites and/or pulmonary effusion reduces pulmonary compliance -Respiratory alkalosis: Hypoxemia → compensatory hyperventilation -Hepatopulmonary syndrome: Pulmonary vasodilation → intrapulmonary shunt → hypoxemia -Portopulmonary HTN → PAP > 25 mmHg in the setting of portal hypertension

How does pregnancy affect the oxyhemoglobin dissociation curve?

-Right shift (Increased p450) → facilitates O2 unloading to the fetus

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

-Right-to-left shunt → the FA/FI of an agent with low solubility will be affected more than one with high solubility

Describe the airway in the patient with Trisomy 21.

-Risk for difficult ventilation and intubation -Small mouth -Large tongue -Palate is narrow with a high arch -Midface hypoplasia -Atlantoaxial instability (C1&C2 subluxation) -Subglottic stenosis -OSA -Chronic pulmonary infection

What is the risk of neuraxial anesthesia in the patient with coagulopathy? -What lab values are considered contraindications to a neuraxial technique?

-Risk of spinal or epidural hematoma -Neuraxial blocks are contraindicated in significant pathologic or therapeutic coaguopathic state -Platelet count < 100,000 -PT, aPTT, and/or bleeding time twice the normal value

Discuss the use of the aminosteroid neuromuscular blocker in patients with chronic kidney disease.

-Rocuronium is associated with an unpredictably increased duration of action -Vecuronium is associated with a prolonged duration of action -Pancuronium is primarily eliminated by the kidneys and has no use in this population

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 -Prematurity -Newborns of diabetic mothers -Children with diabetes who received insulin on the day of surgery -Children who receive glucose-based parenteral nutrition

Where do the heart sounds match up on the left ventricular pressure loop?

-S1: Closure of mitral and tricuspid valves (marks onset of systole) -S2: Closure of aortic & pulmonic valves (marks onset of diastole) -S3: May suggest systolic dysfunction (normal in kids and athletes) -S4: May suggest diastolic dysfunction

Describe the autonomic innervation of the heart.

-SNS: Cardiac accelerator fibers arise from T1-T4 -PNS: Vagus Nerve

What ligament covers the sacral hiatus and what is the significance of this?

-Sacrococcygeal ligament -This ligament is punctured during the caudal approach to the epidural space

What signs and symptoms suggest a congenital diaphragmatic hernia?

-Scaphoid abdomen (sunken in), respiratory distress, barrel chest, cardiac displacement

Detail the anesthetic management of ALS.

-Sch can cause lethal hyperkalemia -Increased sensitivity to nondepolarizing neuromuscular blockers -Bulbar muscle dysfunction increases the risk of pulmonary aspiration -Consider postoperative mechanical ventilation

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!

Is succinylcholine safe to give to a patient with renal failure?

-Sch is safe in patients with renal failure that have a normal serum K+ -Renal failure patients with an elevated K+ do not have an increased release, but the normal release may increase serum K+ to a dangerous level

How does succinylcholine affect intraocular pressure?

-Sch will transiently IOP by 5-15 mmHg for 10 mins -Weigh this option against the need to rapidly secure the airway -De-fasciculating dose of NDNMB does not attenuate the increase in IOP

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 is the most common sign of local anesthetic systemic toxicity?

-Seizure -Bupivacaine is the exception → cardiac arrest can occur before seizures

Envision the anatomy of the spinal cord and spinal nerve in cross section.

-Sensory neurons from the periphery via the dorsal nerve root -Motor and autonomic neurons exit via the ventral nerve roots

Which type of nerve injury provides a greater risk for long term injury (sensory or motor)

-Sensory → more common, less serious, usually resolve on their own with in 5 days -Motor → less common, more serious

Name 3 conditions that are associated with a high risk of developing DIC.

-Sepsis (highest risk = gram (-) bacteria) -Obstetric complications (highest risk = preeclampsia, placental abruption, AFE) -Malignancy (highest risk = adenocarcinoma, leukemia, lymphoma)

How do serum creatinine and creatinine clearance change in the elderly?

-Serum creatinine does not change -Even though GFR is reduced, muscle mass also declines with age, so less creatinine is produced -Creatinine clearance however, is decreased

Discuss the use of lipid emulsion for the treatment of LAST.

-Serves as an intravascular reservoir that sequesters LA and reduces the plasma concentration Treatment for LAST: -Bolus = 20% 1.5 mL/kg over 1 minute -Infusion = 0.25 mL/kg/min -Can repeat bolus up to 2 more times and increase infusion to 0.5 mL/kg/min -Continue infusion for 10 minutes after achieving hemodynamic stability *Max recommended dose is 10 mL/kg in the first 30 mins

List 4 contraindications to the intra-aortic balloon pump.

-Severe aortic insufficiency -Descending aortic disease -Severe peripheral vascular disease -Sepsis

What is the blood:gas solubility for: -Sevo -Des -Iso -N2O

-Sevo = 0.65 -Des = 0.42 -Iso = 1.45 -N2O = 0.46

What are the vapor pressures: -Sevo -Des -Iso -N2O

-Sevo = 157 -Des = 669 -Iso = 238 -N2O = 38,770 -Halogenated anesthetics have vapor pressures < ATM pressure → liquid state. N2O has vapor pressure > ATM pressure → gaseous state

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

-Sevo: Not stable/Compound A -Des: Not stable/Carbon monoxide (if soda lime is desiccated) -Iso: Not stable/Carbon monoxide (if soda lime is desiccated) -N2O: Stable/None

What are the theoretical consequences of sevoflurane metabolism?

-Sevoflurane is not metabolized to TFA, but its biotransformation does result in the liberation of inorganic fluoride ions → High output renal failure (no literature to support this) -S/Sx of high output renal failure → polyuria, hypernatremia, hyperosmolarity, increased creatinine, inability to concentrate the urine

What are the fresh gas flow recommendations for sevoflurane? -Why is this?

-Sevoflurane should be administered at a rate of 1L/min for no more than 2 MAC hours, after that FGF should be increased to 2L/min

Name 3 drugs that can be used to treat postoperative shivering.

-Shivering increases O2 consumption up to 400-500% -Meperidine (kappa) -Clonidine (alpha-2) -Dexmedetomidine (alpha-2)

Discuss the potential complications of opioid reversal with naloxone.

-Short duration -SNS stimulation -N/V -Fetal withdrawal

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

Compare and contrast the site of action for spinal vs epidural anesthesia.

-Site of Action: Spinal Anesthesia -The primary site of local anesthetic action is on the myelinated preganglionic fibers of the spinal nerve roots -Local anesthetics also inhibit neural transmission in the superficial layers of the spinal cord -Site of Action: Epidural Anesthesia -Local anesthetics in the epidural space must first diffuse through the dural cuff before they can block the nerve roots -Local anesthetics also leak through the intervertebral foramen to enter the paravertebral area. Here, local anesthetics cause multiple paravertebral blocks

Which position is most likely to cause venous air embolism?

-Sitting position -Venous air embolism → right heart → pulmonary vasculature → increased dead space and RV workload -Paradoxical air embolism → right heart → patent foramen ovale → left heart → systemic circulation → stroke

Discuss the presentation of hypocalcemia.

-Skeletal muscle cramps -Nerve irritability → paresthesia and tetany -Chvostek sign -Trousseau sign -Laryngospasm -Mental status changes → seizures -Long QT interval

In what situation can atropine cause a paradoxical bradycardia?

-Small doses (< 0.5 mg in an adult) can cause paradoxical bradycardia -Due to inhibition of the presynaptic M1 receptor on vagal nerve endings

List 6 indications for the Bullard laryngoscope.

-Small mouth opening -Impaired cervical spine mobility -Short, thick neck -Treacher Collins syndrome -Pierre-Robin syndrome

List 10 risk factors for difficult tracheal intubation.

-Small mouth opening -Palate is narrow with high arch -Long upper incisors -Interincisor distance < 3 cm -Mallampati class 3 or 4 -Mandibular protrusion test class 3 -Poor compliance of submandibular space -Thyromental distance < 6 cm or > 9 cm -Neck is thick and short -Poor AO joint mobility (can't touch chin to chest and/or extend neck)

How does sodium bicarbonate affect local anesthetic onset of action? -Are there any other benefits?

-Sodium bicarbonate shortens local anesthetic onset time -Alkalization increases the number of lipid soluble molecules, which speeds up the onset of action. -Mix 1 mL of 8.4% sodium bicarbonate with 10 mL of local anesthetic -The addition of sodium bicarbonate will also reduce the pain during injection

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

What drugs are used in the treatment of a carcinoid crisis?

-Somatostatin (octreotide or lanreotide) → inhibits release of vasoactive substances from carcinoid tumors -Antihistamines (H1 & H2) → diphenhydramine + ranitidine or cimetidine -5-HT3 antagonists -Steroids -Phenylephrine or vasopressin for hypotension

Which patients are at the highest risk of latex allergy?

-Spina bifida/myelomeningocele -Atopy -Health care workers -Food allergy to banana, kiwi, mango, papaya, pineapple, tomato

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

What are the 2 most important determinants of fluid transfer between the capillaries and interstitial space?

-Starling forces -Glycocalyx

What are two primary ways a heart valve can fail?

-Stenosis: There is a fixed obstruction to forward flow during chamber systole, the chamber must generate a higher than normal pressure to eject the blood. -Regurgitation: The valve is incompetent, some blood flows forward and some blood flows backwards during chamber systole

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 -If the patient is > 20 kg → patient's weight in kg + 40

What is the treatment for acute adrenal crisis?

-Steroid replacement therapy (hydrocortisone 100 mg + 100-200 mg q24h) -ECF volume expansion (D5NS is best) -Hemodynamic support

List 6 situations that can precipitate autonomic hyperreflexia.

-Stimulation of hollow organs - bladder, bowel, uterus -Bladder catheterization -Surgery - especially cystoscopy or colonoscopy -Bowel movement -Cutaneous stimulation -Childbirth

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

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

At the level of the ankle, which nerve is not immediately adjacent to a vascular structure?

-Superficial peroneal nerve -All of the other nerves are very close to an artery and/or vein -Blockade of the superficial peroneal nerve is LEAST likely to result in an intravascular injection

List 3 factors that worsen tracheobronchial compression in the patient with an anterior mediastinal mass.

-Supine position -Induction of GA -PPV

What is the treatment for TURP syndrome?

-Support oxygenation and cardiovascular support -Tell surgeon to abort procedure -Labs and 12-lead EKG -If Na+ > 120 mEq/L, restrict fluids and give furosemide -If Na+ < 120 mEq/L give 3% NaCl at < 100 mL/hr -Midazolam for seizures

What types of surgical procedures are well suited for a supraclavicular block? -Which are not?

-Supraclavicular block targets the trunks/divisions of the brachial plexus. -It provides a dense block for surgeries at or below the elbow -Not ideal for shoulder surgeries

List 8 consequences of too much Ca+2 inside of the skeletal myocyte.

-Sustained muscle contraction -Accelerated metabolic rate and depletion of ATP -Increased O2 consumption -Increaed CO2 and heat production -Mixed respiratory and lactic acidosis -Sarcolemma breaks down -Potassium and myoglobin leak into systemic circulation -Rigidity from sustained contraction

Discuss the cardiovascular 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, cardiac output, and blood pressure. Volume loading with 15 mL/kg and vasopressors will minimize hypotension Bradycardia is caused by: -Blockade of the pregangnlionic cardioaccelerator fibers at T1-T4. This promotes a relative increase of parasympathetic tone -Unloading of cardiac mechanoreceptors (Bezold-Jarisch reflex) -Unloading of the stretch receptors in the SA node

Which anesthetic agents should be avoided in the hyperthyroid patient?

-Sympathomimetics -Anticholinergics -Ketamine -Pancuronium

Describe the cardiovascular effects of isoproterenol.

-Synthetic catecholamine that stimulate Beta-1 and Beta-2 -Increases HR, contractility, and myocardial O2 consumption -Decreases SVR, which reduces diastolic BP (May reduce coronary perfusion pressure) -Can cause severe dysrhythmias and tachycardia -Vasodilates nonessential vascular beds (muscle and skin)

What information can you learn from the arterial BP waveform?

-Systolic + Diastolic BP -Pulse pressure -Contractility (upstroke) -Stroke volume (area under the curve) -Closure of aortic valve (dicrotic notch)

What is the difference between systolic and diastolic heart failure?

-Systolic Heart Failure: The ventricle doesn't empty well -The hallmark of SHF is decreased ejection fraction with an increased end-diastolic volume. -Volume overload commonly causes systolic dysfunction. -Diastolic Heart Failure: The ventricle doesn't fill properly -DHF occurs when the heart is unable to relax and accept the incoming volume, because ventricular compliance is reduced. -Defining characteristic of diastolic dysfunction of symptomatic heart failure with a normal ejection fraction

How does systolic and diastolic function change in the elderly?

-Systolic function → no change -Diastolic function decreases as a function of reduced compliance and increased wall stiffness that impairs myocardial relaxation

Discuss the pathophysiology of transfusion-related acute lung injury.

-TRALI is probably caused by HLA and neutrophil antibodies present in the donor plasma -FFP and platelets contain the highest concentration of these antibodies.

What are the signs and symptoms of a carcinoid crisis?

-Tachycardia -Hyper or hypotension -Intense flushing -Abdominal pain -Diarrhea

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, it is bordered medially by the semitendinosus 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 femurs and the semitendonosus muscles

Describe the anatomy and physiology of the Bainbridge reflex.

-The Bainbridge reflex increases the HR when venous return is too high, this minimizes venous congestion and promotes forward flow. -Sensor: SA node, RV, pulmonary veins -Afferent: Vagus -Control: Vasomotor center in medulla -Efferent: Vagus (inhibition) -Effector: SA node increases HR -Treatment: None

Describe the anatomy and physiology of the Bezold-Jarisch reflex.

-The Bezold-Jarisch reflex decreases HR when venous return is too low, this gives an empty heart adequate time to fill -Sensor: Cardiac mechanoreceptors and cardiac chemoreceptors -Afferent: Vagus -Control: Vasomotor center in the medulla -Efferent: Vagus -Effector: SA node decreases HR and AV node decreases conduction velocity -Treatment: Restore preload and increase HR (EPI is best)

What is the Cobb angle, and what is its significance?

-The Cobb angle describes the magnitude of the spinal curvature

Describe the diameter index safety system.

-The DISS presents inadvertent misconnections of gas hoses. Each gas hose and connector are tied and threaded for each individual gas

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 → increased rate of rise → faster equilibration of FA/FI → faster onset -High solubility → more uptake into the blood → decreased rate of rise → slower equilibration of FA/FI → slower onset

Which law determines which drugs will pass through the placenta?

-The Fick principle Drug characteristics that favor transfer -Low molecular weight (, 500 daltons) -High lipid solubility -Unionized -Nonpolar

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

-The GABA-A receptor -Stimulation of GABA-A → chloride influx → neuronal hyperpolarization

How does the glomerular filtration rate change in the elderly?

-The GFR decreases -Normal GFR 125 mL/min, this decreases 1 mL/min/year after age 40 Consequences -Risk of fluid overload -Impaired drug elimination

How does tubuloglomerular feedback affect renal autoregulation?

-The JXG apparatus is located in the distal tubule, specifically in the region that passes between the afferent and efferent arterioles -Tubuloglomerular feedback about the Na+ and Cl- composition in the distal tubule affects arteriolar tone

Which region of the heart is most susceptible to myocardial ischemia? -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 supply and reduces blood flow. The high compressive pressure in the LV subendocardium coupled with a decreased coronary artery blood flow during systole increase coronary vascular resistance and predisposes this region to ischemia

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

-The MELD score analyzes bilirubin, INR, and serum creatinine to determine hepatic function -Low risk < 10 -Intermediate risk = 10-15 -High risk > 15

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

What is the risk of a patent foramen ovale?

-The PFO increases the risk of paradoxical embolism → embolus goes to the brain instead of the lungs -30% of adults have a patent foramen ovale

Describe the pin index safety system.

-The PISS prevents inadvertent misconnections of gas cylinders -The presence of one washer between the anger yoke assembly and the stem of the tank may allow the PISS to be bypassed

What is the best bedside tool to identify undiagnosed OSA? -How do you interpret the findings?

-The STOP-BANG scoring system is a bedside tool that allows you to predict the likelihood that a patient has undiagnosed OSA -High risk = > 3 questions answered yes -Low risk = < 3 questions answered yes

Define volume of distribution and recite the equation. -What does Vd assume?

-The Vd describes the relationship between a drug's plasma concentration following a specific dose - theoretical measure of how drug distribute through the body. -Vd assumes two things: 1. The drug distribute instantaneously 2. The drug is not subjected to biotransformation or elimination before it fully distributes

Discuss the anatomy and innervation of the anterior and posterior branches of the femoral nerve.

-The anterior branch innervates the ventral surface of the thigh and the sartorius muscle -The posterior branch innervates the quadriceps muscle, knee joint and its medial ligament -The posterior branch gives rise to the saphenous nerve

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 -It supplies the anterior cord in the thoracolumbar region → originates between T11-T12 (usually on the left)

Describe the architecture of an atom.

-The atom is the basic building block that makes up all matter -Protons (+) charge -Neutrons (neutral) charge -Electrons (-) charge -Protons and neutrons are in the center of the atom (nucleus), electrons orbit the nucleus in the electron cloud

Describe the anatomy and physiology of the baroreceptor reflex.

-The baroreceptor reflex regulates short term BP control. -When BP rises, the baroreceptor reflex decreases HR, contractility, and SVR -When the BP falls, the baroreceptor reflex increases HR, contractility, and SVR

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

-The concentration effect explains the phenomenon. -We can safely deliver a much higher inspiratory concentration, which negates the small difference in 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. Also true for alfentanil and sufentanil to a lesser degree. -Remifentanil is an 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 is infused.

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

What is the difference between a strong and weak acid or base?

-The difference is the degree of ionization -If you put a strong acid or base in water, it will ionize completely -If you put a weak acid or weak base in water, a fraction will be ionized and a fraction will be unionized

How do hyperthyroidism and hypothyroidism affect MAC? -Why?

-The do not directly affect MAC -However, the changes in cardiac output may affect the anesthetic uptake of inhaled agent

How do you block the ulnar nerve at the elbow?

-The elbow is flexed 90 degrees and 3-5 mL of LA is injected between the olecranon and medial epicondyle of the humerus -Using too high a volume can compress the ulnar nerve → ischemic injury

What is the glycocalyx and what factors disrupt it?

-The endothelial glycocalyx forms a protective layer on the inferior wall of the blood vessel. It can be viewed as the gatekeeper that determines what can pass from the vessel into the interstitial space. It also contains anticoagulant properties. -Disruption of the glycocalyx → capillary leak Conditions that impair the integrity of the glycocalyx -Sepsis -Ischemia -Diabetes mellitus -Major vascular surgery

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

-The failsafe device checks pressure, not flow -If there is a pipeline crossover, the oxygen pressure failure device will not catch it

Describe the organization of the 3 neuron pathway common to the spinal tracts.

-The first-order neuron links the peripheral nerve to the spinal cord or brainstem -The second-order neuron links the spinal cord or brainstem to a subcortical structure -The third-order neuron links the subcortical structure to the cerebral cortex

How does neuraxial anesthesia affect GI function?

-The gut receives parasympathetic innervation from the vagus nerve (CN X) and sympathetic innervation from the sympathetic chain between T5-L2. -Inhibition of the sympathetic chain between T5-L2 allows parasympathetic output to the gut to function unopposed. -Inhibition of sympathetic outflow causes sphincters to relax and increase peristalsis

Discuss the balance of prostacyclin and thromboxane in the patient with preeclampsia.

-The healthy placenta produces thromboxane and prostacyclin in equal amounts -The patient with preeclampsia produces up to 7x more thromboxane than prostacyclin -TXA2 favors vasoconstriction, platelet aggregation, and reduced placental blood flow

What factors affect the accuracy of the noninvasive blood pressure cuff measurement?

-The ideal length is long enough to wrap around 80% of the extremity -The ideal width is 40% the circumference of the patients arm

How does pregnancy affect the mother's arterial blood gas?

-The increase in minute ventilation results in a respiratory alkalosis with renal compensation -Arterial pH = no change -PaO2 = Increased (104-108 mmHg) -PaCO2 = Decreased (28-32 mmHg) -HCO3- = Decreased (20 mmol/L)

Why is an inhalation induction faster with a neonate than with an adult?

-The increased ratio of ventilation relative to the size of the FRC explains the quicker induction. -A faster turnover of FRC allowed for a speedier development of anesthetic partial pressure inside the alveoli.

Describe the structure an function of the flow tube.

-The internal diameter of the flow tube is narrowest at the base and progressively widens along its ascent -Laminar flow is dependent on gas viscosity (Poiseuille) -Turbulent flow is dependent on gas density (Graham)

How does the kidney contribute to acid-base balance? -What other organ is essential to this process?

-The kidneys maintain acid-base balance by titrating hydrogen in the tubular fluid, which creates acidic or basic urine -The lungs excrete volatile acids (CO2) and the kidneys excrete non-volatile acids

Describe the anatomy of the psoas compartment.

-The lumbar plexus is contained within a sheath inside the psoas compartment -It is lateral to the vertebral column, anterior to the quadratus lumborum muscle, and posterior to the psoas muscle

What is lymph and how does the lymphatic system work?

-The lymph system removes fluid, protein, bacteria, and debris that has entered the interstitium. It accomplishes this goal with a pumping mechanism that propels lymph though 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.

Which nerve is most likely to be missed during an axillary block? -Which terminal branch is not included in an axillary block?

-The musculocutaenous nerve resides in the coracobrachialis muscle - it's not part of the neuromuscular sheath that surrounds the axillary artery -It must be blocked separately

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

-The number of blood vessels passing through the liver is reduced → increased hepatic vascular resistance -To offset this increased resistance, the body creates collateral vessels that bypass the liver → portosystemic shunts -Since this blood bypasses the liver → drugs and toxins remain in the systemic circulation for a longer period of time.

Explain latent heat of vaporization and apply this to anesthetic vapor inside of a vaporizer.

-The number of calories required to concert 1 gram of liquid to vapor without a temperature change -Anesthetic liquid exerts a vapor pressure, this means some of the agent exists as liquid and some exists as a gas -FGF flows over the liquid, carrying away some of the agent in the gas phase -This cools the remaining liquid, which reduces the vapor pressure -Net result is a decreased in the vaporizer output

What is the function of a phase 2 reaction? -List 5 common substrates.

-The phase 2 reaction conjugates an endogenous, highly polar, water soluble substrate to the molecule. This results in a water soluble, biologically inactive molecule ready for excretion. -Some drugs may proceed directly to a phase 2 reaction Examples: -glucuronic acid -glycine -acetic acid -sulfuric acid -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 healthy patients, this rarely results in respiratory compromise -In patient with respiratory disease, such as COPD, phrenic nerve paralysis may result in severe dyspnea, hypercapnia, and hypoxemia

Describe the structure of 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 -Composed of 5 subunits that align around an ion conducting pore - 2 alpha, 1 beta, 1 delta, and 1 epsilon subunits

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 osmotic pressure and what is its primary determinant?

-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 of their molecular weights

Which position provides the most optimal V/Q matching in the patient with ARDS?

-The prone position provides optimal V/Q matching

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

-The require a dosage adjustment to both -Intrathecal - CSF volume is reduced → greater spread of LA -Epidural - volume of epidural space is reduced → greater spread of LA

What is angioedema?

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

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 -It provides sensory innervation from he medial aspect of the knee to the medial malleolus - no motor component -Useful when combined with a popliteal or ankle block

Describe the anatomy of the sciatic nerve.

-The sciatic nerve arises from L4-L5 and S1-S3 -The sciatic nerve is actually two nerves contained within a sheath (tibial n. and peroneal n.) -It 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 third of the thigh. This is where the sciatic nerve divides into tibial and common peroneal nerves

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 profound clinical effect -Flatter slope = Higher doses are required to increase the clinical effect

Compare and contrast the level of the conus medullaris and dural sac in the adult vs infant.

-The spinal cord ends in a taper as the conus medullaris -Adult: L2-L3, Infant L3 -The subarachnoid space terminates at the dural sac -Adult S2, Infant S3

Which approach to the brachial plexus is most likely to cause Horner's syndrome? -What are the clinical implications of this?

-The stellate ganglion is located at C7 - this structure is often blocked during the interscalene approach. -Horner's syndrome indicates a successful block → ptosis, miosis, and anhidrosis

What happens when you accidentally inject local anesthetic into the subdural space during a SAB? -How about during an epidural?

-The subdural space is a potential space between the dura mater and the arachnoid mater. -Spinal dose → failed spinal -Epidural dose → High spinal with delayed onset (15-20 minutes)

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 → oliguria and edema -This predisposes the kidneys to ischemic injury and nephrotoxicity

Define Dalton's law. List several examples of how it can be used in the operating room.

-The total pressure is equal to the sum of the partial pressures exerted by each gas in the mixture P total = P1+P2+P3

Who is at risk for ulnar nerve injury?

-The unlar nerve is the most commonly injured nerve. At risk -Male gender (especially if > 50 years) -Preexisting ulnar neuropathy -Extremes of body hiatus (very thin or obese) -Prolonged hospital stay/bedrest

Describe sensory innervation of the upper extremity.

-The ventral portion is supplied by the median, ulnar, and musculocutaneous nerves (lateral and medial cords) -The dorsal portion is supplied by the radial and axillary nerves (posterior cord) -The hand is the exception

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

Define therapeutic index.

-Therapeutic index = LD50/ED50 -A drug with a narrow TI has a narrow margin of safety -A drug with a wide TI has a wide margin of safety

What is the most common organism responsible for post-spinal bacterial meningitis?

-There are 2 routes by which an infectious organism can reach the CSF 1. Failure of aseptic technique 2. Bacteria in the patient's blood at the time of SAB -Streptococcus viridans is one of the most common culprits responsible for post-spinal bacterial meningitis. It is commonly found int he mouth, and this is why it's so critical to wear a mask while performing a neuraxial block

What is the relationship between PaCO2 and CBF? -What is the CBF at a normal PaCO2?

-There is a linear relationship between PaCO2 and CBF -At a PaCO2 of 40 mmHg, CBF is 50 mL/100g/min

How does the cardiac conduction system change in the elderly?

-There is fibrosis of the conduction system and loss of SA node tissue -Increased chance of dysthrythmias

How is differential blockade different with epidural anesthesia?

-There is no autonomic differential blockade with epidural anesthesia -Sensory bock is 2-4 dermatomes higher than motor block

What drugs can be used to augment heart rate in the patient with a heart transplant?

-There is no autonomic input from the cardiac accelerator fibers (T1-T4) or the vagus nerve -Drugs that directly stimulate the SA node can be used to increase HR → EPI, isoproterenol, glucagon -Drugs that indirectly stimulate the SA node cannot be used to increase HR → atropine, glycopyrrolate, ephedrine

How do nitroglycerine and nitroprusside affect ICP?

-These agents are cerebral vasodilators, they increase CBF and ICP

Discuss the management of patients with NEC.

-These babies are managed medically, however, bowel perforation necessitates bowel resection and usual colostomy. These patients often have a metabolic acidosis and require substantial fluid replacement -Bowel resection early in life can lead to short gut syndrome

How do isotonic IV fluids distribute to the patient?

-These solutions expand the plasma volume and the ECF -Crystalloids tend to remain in the intravascular space for about 30 minutes before moving to the ECF

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

-Things that distend the LVOT are good for cardiac output, things that narrow the LVOT are bad for cardiac output

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

What is the transcellular potassium shift and what causes it to occur?

-Things that shift K+ into cells result in hypokalemia -Things that shift K+ out of cells result in hyperkalemia

Discuss the anesthetic management of the patient who has previously undergoing Fontan completion.

-This patient has a single ventricle that pumps blood into the systemic circulation - no ventricle to pump blood into the pulmonary circulation -Blood flow into the lungs is completely dependent on negative intrathoraci pressure during spontaneous breathing -PPV disrupts this arrangement -These patient's are preload dependent, don't let them get dry

How do you assess a patient for thoracic outlet syndrome? -Which surgical position increases the likelihood of this complication?

-Thoracic outlet syndrome is more likely to occur in any position where the arms are placed over the head (prone) -During the preoperative interview, ask the patient to clasp her hand behind her head. If she complains of pain, this may suggest an increased risk of thoracic outlet syndrome → may be prudent to tuck the arms while in the prone position

What drugs can be used to provide anticoagulation in a patient who is unable to receive heparin? -How long must each be stopped prior to surgery?

-Thrombin inhibitors can be used to provide anticoagulation in patients who are unable to receive heparin -Bivalirudin → 2-3 hours -Argatroban → 4-6 hours -Hirudin → 8 hours

What are the indications for platelet transfusion?

-Thrombocytopenia (<50,000/uL) → Invasive procedures, neuraxial blockade, most surgeries -Thrombocytopenia (<100,000/uL) → Eye and neurosurgery -Qualitative platelet defect

What surgical procedure can reduce symptoms in the patient with myasthenia gravis?

-Thymectomy brings symptom relief to many patients -Surgical approach is by median sternotomy or by transcervical approach

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 is the purpose of the unidirectional valves in the breathing circuit?

-To ensure that gas moves in one direction -If the valve becomes incompetent, the patient will rebreathe exhaled gas -Definitive fix is to correct the valve, temporary fix is to convert a closed or semi-closed system into a semi-open system

What is the difference between a hypotonic and hypertonic solution?

-Tonicity compares the osmolarity of a solution relative to the osmolarity of the plasma

How long must the tourniquet remain inflated after a Bier block? -Why?

-Tourniquest must be inflated for at least 20 minutes after the LA is injected, premature relieve increases the risk of seizure and/or cardiac arrest -Bier block upper extremity → 300 mmHg -Bier block lower extremity → 300 mmHg or 2x SBP (whichever is higher)

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 begins at 45-60 minutes after inflation, this is the most common reason why patients are unable to tolerate a procedure lasting more than 1 hour

For the patient who received a Bier block, when can you deflate the tourniquet?

-Toxicity is the most significant risk -The tourniquet must remain inflated for a minimum of 20 minutes following local anesthetic injection, this allows enough time for the LA to absorb into the tissue

Describe the presentation of the child who presents with foreign body aspiration.

-Triad of cough, wheezing, and decreased breath sounds on the affected side -Supraglottic obstruction → Stridor -Infraglottic obstruction → Wheezing

What conditions cause a large v wave on the CVP waveform?

-Tricuspid regurgitation -Acute increase in intravascular volume -RV papillary muscle ischemia

What is tic douloureux? -What cranial nerve contributes to this problem?

-Trigeminal neuralgia - CN V → causes excruciating neuropathic pain in the face

What is the difference between trismus and masseter spasm (malignant hyperthermia)? -How should you proceed if the patient presents with either condition?

-Trismus describes a tight jaw that can still be opened -Masseter muscle rigidity describes a jaw that cannot be opened -Trismus is a normal response to Sch -Masseter muscle rigidity is related to increased Ca+2 in the myoplasm → a NMB will not relax the jaw → assume MH until proven otherwise

Discuss local anesthetic allergy and cross sensitivity.

-True allergy to LA is rare -Allergy potential → Ester >> Amide -Ester-type LA's are derivatives of PABA, which can cause an allergic reaction -If a patient has a true LA allergy, choose the opposite class to use

What enzymes metabolize NE and EPI? -What is the final metabolic byproduct?

-Two metabolic pathways for NE and EPI - Monoamine oxidase (MAO) and Catechol-O-methyltransferase (COMT) -The final byproduct of NE and EPI metabolism is vanillymandelic acid (VMA)

Which type of viral hepatitis has the highest incidence?

-Type A = 50% -Type B = 35% -Type C = 15% -Type D = Co-infection with Type B

How is each type of viral hepatitis transmitted?

-Type A = oral/fecal -Type B = percutaneous or sexual contact -Type C = percutaneous -Type D = percutaneous

What is the prescribed prophylaxis regimen after exposure to hepatitis A, B, or C?

-Type A: Pooled gamma globulin, Hep A vaccine -Type B: Hep B immunoglobulin, Hep B vaccine -Type C: Interferon + ribavirin

Describe the 5 types of tracheoesophageal atresia. -Which one is the most common?

-Type C accounts for 90% of all TEFs -Type C → upper esophagus ends in a blind pouch and the lower esophagus communicates with the distal trachea

What is the difference between fast and slow twitch muscle fibers? -How does this relate to neonatal pulmonary mechanics?

-Type I = slow twitch muscle fibers that are built for endurance - resistant to fatigue -Type II = fast twitch muscle fibers that are built for short bursts of heavy work - they tire easily -The neonatal diaphragm has 25% type I fibers (adults have 55%) → neonates tire easily

What are the most common causes of type I and type II DM?

-Type I DM → Autoimmune response (early in life) -Type II DM → Obesity

What is the difference between type I and type II diabetes mellitus?

-Type I DM → characterized by the lack of insulin production -Type II DM → characterized by a relative lack of insulin + insulin resistance

Describe the pathophysiology of the 4 types of hypersensitivity reactions. List examples of each.

-Type I: Immediate hypersensitivity → anaphylaxis, extrinsic asthma -Type II: Antibody-mediated → ABO-incompatability, HIT -Type III: Immune complex mediated → Snake venom reaction, protamine induced vasoconstriction -Type IV: Delayed → Contact dermatitis, graft-vs-host reaction, tissue rejection

What are the most common signs of an anastomotic leak following gastric bypass?

-Unexplained tachycardia is the most sensitive sign of an anastomotic leak → an unexplained HR of > 120 ppm should send up a red flag -Tachycardia → 72% -Fever → 63% -Abdominal pain → 54% -Ketorolac can increase the incidence of this complication → avoid it in the perioperative period

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

-Unique, 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 (80% EPI/20%NE)

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

-Universal FFP donor = AB positive -Universal FFP acceptor = O negative

What blood type is the universal donor for erythrocytes? -How about the universal acceptor?

-Universal RBC donor = O negative -Universal RBC acceptor = AB positive

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

-Unpaired: Epiglottis, thyroid, cricoid -Paired: Corniculate, arytenoid, cuneiform

List 2 indications for retrograde intubation.

-Unstable cervical spine (most common use of RI) -Upper airway bleeding

Discuss the relationship between FiO2 and ROP.

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

Which volatile agents 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 -Des and Iso undergo a much smaller degree of hepatic biotransformation, but there is a small risk of immune mediated hepatic dysfunction

Discuss the use of neuromuscular blockers in burn patients.

-Up-regulation of exntrajunctional receptors begins after 24 hours -Sch is safe within the first 24 hours following the burn, not after 24 hours -The dose of non-depolarizing NMB should be increased 2-3 fold

Contrast the presentation of upper vs lower motor neuron injury.

-Upper motor neuron injury presents with hyperreflexia and spastic paralysis -Lower motor neuron injury presents with impaired reflexes and flaccid paralysis

What conditions allow extrajunctional receptors to populate the myocyte?

-Upper or lower motor neuron injury -Spinal cord injury -Burns -Skeletal muscle trauma -Cerebrovascular accident -Prolonged chemical denervation -Tetanus -Severe sepsis -Muscular dystrophy

How does uremia affect coagulation? -How can bleeding be minimized in these patients?

-Uremic patients are at increased risk of bleeding -PT, PTT, and platelet counts are normal → bleeding time (measure of platelet function) is increased -First line treatment is desmopressin, cry may be used to provide VIII-vWF -Dialysis improves bleeding time, should be performed within 24 hours of surgery

What is the optimal tidal volume for a morbidly obese patient who is mechanically ventilated?

-Use a tidal volume of 6-8 mL of IBW -Higher tidal volumes only minimally increase PaO2 and may cause sheer stress to the lungs -Control PaCO2 by adjusting the respiratory rate, not by increasing the tidal volume

What steps can be taken to prevent nephrotoxicity from radiographic contrast media?

-Use nonionic iso or low-osmolar contrast instead of hyperosmolar contrast -Use the lowest volume necessary -IV hydration with 0.9% NaCl prior to administration of contrast dye -Sodium bicarbonate injection or infusion -N-acetylcysteine is no longer recommended

What is the mandibular protrusion test and what values suggest an increased risk of difficult intubation?

-Used to assess the function of the temporomadibular joint -Class III indicates a difficult intubation

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 -Normal → 8-10 -Moderate distress → 4-7 -Impending demise → 0-3

Describe the inter-incisor gap. -What is normal?

-Used to assess the patient's ability to open their oral cavity -Normal = 2=3 finger breaths or 4 cm

Describe the Mallampati score.

-Used to assesses the oropharyngeal space. -Pneumonic - PUSH* -Class I: Pillars, Uvula, Soft palate, Hard palate -Class II: Uvula, Soft palate, Hard palate -Class III: Soft palate, hard palate -Class IV: Hard palate

What is the thyromental distance and what values suggest an increased risk of difficult intubation?

-Used to estimate the size of the submandibular space -Measure from the tip of the thyroid cartilage to the tip of the mentum. -< 6 cm or > 9 cm = worrisome

What are unique side effects of epidural triamcinolone?

-Used to treat lumbar disc disease. It is associated with a higher incidence of skeletal muscle weakness and it is more likely to cause sedation and anorexia

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

-Usually due to a reduction in static compliance → PIP and PP increase -Endobronchial intubation -Pulmonary edema -Pleural effusion -Tension pneumothorax -Atelectasis -Chest wall trauma -Abdominal insufflation -Ascites -Trendelenburg position -Inadequate muscle relaxation

What is the most common cause of postpartum hemorrhage? -What are the risk factors?

-Uterine atony is the most common cause of postpartum hemorrhage Risk factors -Multiparity -Multiple gestations -Polyhydamnios -Prolonged oxytocin infusion prior to surgery

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 does the cerebral oximeter work? -What value is considered a significant change from baseline?

-Utilizes near-infrared spectroscopy to measure cerebral oxygenation -Analyzes non-pulsatile cerebral perfusion based on the assumption that 75% of perfusion is venous/25% of perfusion is arterial. -A > 25% change from baseline suggests a reduction in cerebral oxygenation

How does vasopressin increase blood pressure?

-V1 receptor stimulation → intense vasoconstriction -V2 receptor stimulation → increases intravascular volume by stimulating the synthesis and insertion of aquaporins into the walls of collecting ducts

What is the antibiotic of choice to treat MRSA? -What are the special considerations for the administration of this antibiotic?

-Vancomycin -To reduce histamine release and hypotension, vancomycin should be administered at a rate of 10-15 mg/kg over 1 hour -The histamine response can be minimized by diphenhydramine and cimetidine 1 hour before anesthesia

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

-Vapor pressure: The pressure exerted by a vapor in equilibrium with its liquid or solid phase inside of a closed container -Vapor pressure is directly proportional to temperature

How is carbon dioxide transported in the blood?

-Venous blood transports it to the lungs, where it's excreted into the atmosphere -Mechanisms of CO2 transport: -Bicarbonate = 70% -Bound to Hgb = 23% -Dissolved in plasma = 7%

List all the antidotes for warfarin. -When should each be used?

-Vitamin K (10-20 mg PO, IM, or IV) may be used to reverse warfarin for non-emergent, minor surgical procedures -This requires 4-8 hours to restore the concentration of vitamin K dependent clotting factors -Emergent or high-risk procedures require reversal with FFP (1-2 units), recombinant factor VIIa, or prothrombin complex concentrate

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

-Vitamin K is required to synthesize factors II, VII, IX, and X. Absorption of vitamin K is dependent on the presence of bile in the gut -Anticoagulants that are dependent on vitamin K: Proteins S, C, and Z

How do halogenated anesthetics affect evoked potentials? How about N2O?

-Volatile agents decrease amplitude and increase latency -N2O can potentiate this effect, it should not be used during neuromonitoring

Compare and contrast the effects of halogenated anesthetics and N2O on cerebral blood flow.

-Volatile agents uncouple to CMRO2/CBF relationship -N2O increases CRMO2 and CBF appropriately

How do halogenated anesthetics contribute to hypercarbia?

-Volatile anesthetics cause a dose dependent depression of the central chemoreceptor and the respiratory muscles → hypercarbia -Respiratory pattern is altered → decreased Vt and compensatory increased RR -Response to CO2 is impaired -Motor neuron output and muscle tone to upper airway is impaired

How do halogenated anesthetics affect cerebral metabolic rate?

-Volatile anesthetics reduce CMRO2, but only to the extent that they reduce electrical activity -Once the brain is isoelectric (1.5-2 MAC), volatile agents cannot reduce CMRO2 any further

Compare and contrast volume controlled and pressure controlled ventilation.

-Volume control → 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 -Pressure control → Delivers a preset inspiratory pressure over a predetermined time. Since the pressure and time are fixed, the tidal volume and inspiratory flow will be variable and dependent on the patient's lung mechanic. If airway resistance rises or lung compliance decreases, then tidal volume will suffer and a higher inspiratory flow ll be required to achieve the preset airway pressure.

List 5 indications for dialysis.

-Volume overload -Hyperkalemia -Severe metabolic acidosis -Symptomatic uremia -Overdose with a drug that is cleared by dialysis

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

How do you treat the patient with an intracerebral bleed who is on warfarin?

-Warfarin can be reversed with FFP, prothrombin complex concentrate, and/or recombinant factor VIIa -Vitamin K is not the best option for acute warfarin reversal

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 -This process prevents anaphylaxis in IgA deficient patients

Describe the distribution of body water.

-Water represents 60% of TBW = 42L

What is Eisenmenger syndrome?

-When a patient with a left-to-right shunt develops pulmonary HTN, which reverses the flow through the shunt → right-to-left shunt

What conditions increase the risk of failure to capture?

-When the myocardium becomes more resistant to depolarization -Hyper and Hypokalemia -Hypocapnia -Hypothermia -Myocardial Infarction -Fibrotic tissue buildup around pacing leads -Antiarrhythmic medications

If type O- uncrossmatched blood is administered, most people may safely receive Rh-positive blood. Name 2 populations where Rh-negative blood is best.

-Woman of child bearing age -Patient has not received a previous transfusion

What are androgenic effects?

-Women become masculinized, men become feminized

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

Can you calculate the stroke volume and/or ejection fraction with a pressure volume loop?

-Yes, simply look at the numbers you need -EF = (SV/EDV) x 100 -Answer = 69%

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

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

Alcohol is cleared from the body via zero-order kinetics. How will this drug's rate of elimination change as plasma drug concentration change?

-Zero-order kinetics: A constant AMOUNT of drug is eliminated per unit time. -Examples: aspirin, phenytoin, warfarin, heparin, theophylline

The tip of the PAC should be positioned in West lung zone _____.

-Zone III

What happens when you put an acid in a basic solution? -How about an acidic solution?

"Like dissolves Like" An acid in a basic solution -An acidic drug will be highly ionized in a basic pH An acid in an acidic solution -An acidic drug will be highly unionized in an acidic pH

Discuss the PK/PD profile of remifentanil.

"Rapid On Rapid Off" -Context-sensitive half-time is about 4 minutes, regardless of infusion length -Maintencance infusion = 0.1 - 1.0 mcg/kg/min -Calculated based on LBW

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

*Best treatment is prevention -Post-intubation laryngeal edema can occur with cuffed or uncuffed tubes -Maintain an air leak < 25 cmH2O

What factors affect myocardial contractility?

*Chemicals affect Contractility - particularly Calcium

List the possible causes of a non-gap acidosis.

*Mneumonic: HARDUP -Hypoaldosteronism -Acetazolamide -Renal tubular acidosis -Diarrhea -Ureterosigmoid fistula -Pancreatic fistula -Large volume resuscitation with NaCl solutions can cause a non-gap metabolic acidosis with hypercholoremia

List the possible causes of an anion gap acidosis.

*Mneumonic: MUDPILES -Methanol -Uremia -DKA -Paraldehyde -Isoniazid -Lactate -Ethanol, ethylene glycol -Salicylates

What conditions increase the risk of Torsades de points?

*Mneumonic: Pointes -Phenothiazines -Other meds (methadone, droperidol, amiodarone w/ hypokalemia) -Intracranial bleed -No known cause -Type I antiarrhythmics -Electrolyte disturbances (Low K+, Ca+2, or Mg+2) -Syndromes (Romano-Ward, Timothy)

Should shoulder braces be used for the patient in Trendelenburg position? -Why or why not?

*Never use shoulder braces, a non-sliding mattress is a safer option -If shoulder braces are used, they should be placed at the distal end of each clavicle -Shoulder braces applied near the base of the neck or midway along the clavicle increase the risk of a compression injury

List 5 risk factors for difficult mask ventilation.

*Pneumonic - BONES -Beard -Obese (BMI > 26 kg/m2) -No teeth -Elderly (age > 55 years) -Snoring

What hormones are released from the anterior pituitary gland?

*Pneumonic - FLAT PiG -Follicle-stimulating hormone -Lutenizing hormone -Adrenocorticotropic hormone -Thyroid stimulating hormone -Prolactin -Growth hormone

What are the common causes of fetal deceleration patterns?

*Pneumonic: VEAL CHOP -Variable decels → Cord compression -Early decels → Head compression -Accelerations → Ok or give oxygen -Late decels → Placental insufficiency

What drugs can exacerbate SLE?

*Pneumonoic: PISSED CHIMP -Pregnancy -Infection -Surgery -Stress -Enalapril -D-penicillamine -Captopril -Hydralazine -Isoniazid -Methyldopa -Procainamide

What are 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 is the treatment for hypercalcemia?

-0.9% NaCl -Loop diuretic (furosemide)

What is the specific gravity of CSF? -What factors increase or decrease the specific gravity of CSF?

-1.002 - 1.009

Discuss the management of hypoxemia during one-lung ventilation.

-100% FiO2 -Confirm DLT position with bronchoscope -CPAP 10 cmH2O to non-dependent lung -PEEP 5-10 cmH2O to dependent lung -Alveolar recruitment maneuver -Clamp the PA to the non-dependent lung -Resume 2 lung ventilation

What is the treatment for acute bronchospasm?

-100% FiO2 -Deepen anesthetic (volatile agent, propofol, lidocaine, ketamine) -Inhaled beta-2 agonist (albuterol) -Inhaled anticholinergic (ipratropium) -Epinephrine 1 mcg/kg IV -Hydrocortisone 2-4 mg/kg IV (takes several hours to have an effect) -Aminophylline -Helium-oxygen reduces airway resistance *Montelukast is not used in the treatment of acute bronchospasm

What is the treatment for laryngospasm?

-100% FiO2 -Remove noxious stimulation -Deepen anesthesia -CPAP 15-20 cmH2O -Open the airway (head extension, chin lift) -Larson's maneuver -Succinylcholine

Discuss the treatment of carbon monoxide poising.

-100% FiO2 until CoHgb is < 5% for 6 hours -Hyperbaric oxygen if CoHgb > 25% or the patient is symptomatic

You have administered 30 mg of esmolol to a patient after a sudden (and profound) elevation in heart rate. After three half-lives, what percentage of your initial dose remains in the patient's bloodstream?

-12.5% of the drug remains in the patient's bloodstream.

Describe the general architecture of the G protein second messenger system.

-1st messenger - extracellular signal -Receptor - responds to the extracellular signal -G protein - turns on or turns off an effector -Effector - activates or inhibits the second messenger -2nd messenger - primary intracellular signal -Enzymatic cascade - a bunch of steps you don't have to worry about -Cellular response - causes a physiologic change

Describe the Practice Guidelines for Preoperative Fasting and Use of Pharmacologic Agents to Reduce the Risk of Pulmonary Aspiration.

-2 hours = Clear liquids -4 hours = Breast milk -6 hours = Nonhuman milk, infant formula, solid food -8 hours = Fried or fatty foods

How do you dose Sch in the neonate?

-2 mg/kg due to relatively higher ECF

What is the VACTERL association?

-25-50% of patients with TEF suffer from other congenital anomalies -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

How much blood flow does the liver receive (percentage of cardiac output and total)?

-30% of CO - 1500 mL

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

-5'-Nucleotidase (0-11 units/L) is the most specific indicator of biliary duct obstruction -Y Glutamyll transpeptidae (0-30 units/L) -Alkaline phosphatase (45-115 units/L) is not very specific

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

What is a covalent bond?

-A covalent bond involves the sharing of electrons - this is the strongest type of bond -Single bond = 1 pair of electrons is shared -Double bond = 2 pair of electrons are shared -Triple bond = 3 pair of electrons are shared

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 (Epstein's anomaly) -Truncus arteriosus -Total anomalous pulmonary venous connection

What is acute adrenal crisis? -How does it present?

-A deteriorated version of adrenal insufficiency → medical emergency -Hemodynamic instability/collapse -Fever -Hypoglycemia -Impaired mental status

Discuss the presentation of Guillain-Barre syndrome.

-A flu-like illness usually precedes paralysis by 1-3 weeks S/Sx -Flaccid paralysis begins in the distal extremities and ascends bilaterally towards the proximal extremities, trunk, and face -Intercostal muscle weakness impairs ventilation -Sensory deficits → parenthesis, numbness, pain -Autonomic dysfunction → tachycardia or bradycardia, hypo or hypertension, orthostatic hypotension

What is orlistat? -What are the complications of its use?

-A lipase inhibitor that reversibly binds to lipase and hinders the absorption and digestion of consumed fats -Insufficient quantities of vitamin K will impair synthesis of clotting factors 2, 7, 9, and 10 → coagulopathy

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

What is the purpose of a positioning device for a patient in the prone position?

-A positioning device and padding help distribute the patient's weight to the thoracic cage and the boney pelvis. This allows the abdomen to hang freely, which promotes normal diaphragmatic excursion throughout the respiratory cycle -If the abdomen is compressed, intraabdominal pressure increases, which reduced pulmonary compliance and increases intrathoracic pressure -The Jackson table is better than the Wilson frame or chest rolls

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

-A preductal pulse oximeter is placed on the right upper extremity, while the postductal monitor is usually placed on a lower extremity A difference between the readings indicates -Pulmonary HTN -Right to left cardiac shunt -Return to fetal circulation via the PDA

What is a racemic mixture? List some commonly used examples.

-A racemix mixture contains 2 enantiomers in equal amounts. -Ex: bupivicaine, ketamine, isoflurane, desflurane (not sevo)

What is steady state? -How long does this take to occur?

-A steady state occurs when the amount of drug entering the body is equivalent to the amount of drug being eliminated from the body - stable plasma concentration. -A steady state is achieved after 5 half-times

Can you tell if a drug is an acid or a base by looking at its name? -If yes, how?

-A weak acid is paired with a positive ion such as sodium, calcium, or magnesium -A weak base is paired with a negative ion such as chloride or sulfate

What type of nerve fibers transmit pain?

-A-delta fibers transmit "fast pain" → sharp and well localized -C fibers transmit "slow pain" → dull and poorly localized

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

-ACE inhibitor-related angioedema: Treatment = Epinephrine, antihistamines (benadryl), steroids -Hereditary angioedema (C1 esterase deficiency): Treatment = C1 esterase concentrate or FFP

Where is antidiuretic hormone 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 -Decreased blood volume How ADH increase blood pressure -Increased blood volume from V2 receptor stimulation in the collecting ducts (increased cAMP) -Increased SVR from V1 receptor stimulation in the vasculature (increased IP3, DAG, and Ca+2)

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

-ADH → Water retention -Oxytocin → Uterine contraction and breast feeding

What is obesity hypoventilation syndrome? -How do you identify a patient with this condition?

-AKA Pickwickian syndrome → Long term consequence of untreated OSA -Over time, the respiratory center in the medulla fails to respond to hypercarbia appropriately Diagnostic criteria -BMI > 30 kg/m2 -Awake PaCO2 > 45 mmHg -Dysfunctional breathing during sleep Signs -Obesity -Hypersomnolence during the day -Hypoxemia -Hypercarbia -Respiratory acidosis -Compensatory metabolic alkalosis -Polycythemia -Pulmonary hypertension

What are the anesthetic considerations for multiple system atrophy?

-AKA Shy-Drager syndrome -Causes degeneration of the locus coeruleus, intermediolateral column of the spinal cord, and peripheral autonomic nerves. -Autonomic dysfunction (orthostatic hypotension) -Treat hypotension with volume and direct-acting sympathomimetics -Exaggerated hypertensive response to ephedrine and possibly ketamine.

Which beta blockers have local anesthetic properties? -What is another name for this?

-AKA membrane stabilizing properties -This effect reduces the rate of rise of the cardiac action potential -Ex: propranolol and acebutolol

Discuss the pathophysiology and presentation of postintubation laryngeal edema.

-AKA post-intubation croup -Complication of endotracheal intubation or rigid bronchoscopy -The tracheal mucosa perfusion pressure is 25 cmH2O, using an ETT that is too large or injecting excessive air into the cuff reduces tracheal perfusion → edema → subglottic stenosis → increased work of breathing -The patient presents with hoarseness, a balky cough, and/or stridor. It typically occurs within 30-60 minutes following extubation

What is the best treatment for vasoplegic syndrome?

-AKA refractory hypotension -Vasopressin is the best treatment - 0.5 - 1 unit IV bolus followed by an infusion of 0.03 units/min. -Methylene blue is the next best choice

What are the diagnostic indicators for metabolic syndrome?

-AKA syndrome X -Incorporates a number of disease states that coincide with obesity One must have 3 of the following signs: -Large waist circumference (men > 40 inches, women > 35 inches) -Triglycerides > 150 mg/dL -HDL < 40 mg/dL for men and < 50 mg/dL for women -Blood pressure > 130/85 -Fasting glucose > 100 mg/dL

Describe the anatomy and physiology of the oculocardiac reflex.

-AKA the 5 and dime reflex -Sensor: Pressure to the eye or globe -Afferent: Long and short ciliary n. → ciliary ganglion → ophthalmic division V1 of trigeminal n. → Gasserian ganglion -Control: Vasomotor center in the medulla -Efferent: Vagus -Effector: SA node decreases HR and AV node decreases conduction velocity Treatment: Remove stimulus, administer 100%FiO2 and ensure oxygenation, increase HR (atropine or glycopyrrolate)

Name 2 tests of hepatocellular injury.

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

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

-Abiciximab → 3 days -Eptifibatide → 1 day -Tirofiban → 1 day

List 5 risk factors for difficult invasive airway placement.

-Abnormal neck anatomy -Obesity -Short neck -Limited access to cricothyroid membrane -Laryngeal trauma

What is the risk of using succinylcholine in a patient with up regulation of extrajunctional receptors?

-Absence of exntrajunctional receptors → succinylcholine will transiently increase serum K+ levels by 0.5 - 1.0 mEq/dl for up to 10-15 minutes -Extrajunctional receptors are more sensitive to succinylcholine and they remain open for longer → Life-threatening hyperkalemia

What is desiccation? -How does it apply to soda lime?

-Absorbent that is devoid of water. -Soda lime granules are hydrated to 13-20% -Dessicated soda lime increases the production of carbon monoxide (iso and des) and compound A (sevo)

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

-Absorption into the systemic circulation removes the LA from its site of action and contributes to the termination of its effect -LA's with a greater degree of intrinsic vasodilator effects undergo a faster rate of vascular uptake -Addition of a vasoconstrictor can prolong the duration of action → most benefit in drugs that have a good deal of vasodilation *Cocaine is unique, it always causes vasoconstriction

Which drugs should be avoided in the patient with hepatitis?

-Acetaminophen -Halothane -Amiodarone -Antibiotics → PCN, tetracycline, sulfonamides

How do cholinesterase inhibitors reverse paralysis caused by a non depolarizing neuromuscular blocker?

-Acetylcholinesterase hydrolyzes Ach into choline and acetate -Drugs such as edrophonium, neostigmine, and pyridostigmine reversely inhibit AchE, which indirectly increases the concentration of Ach at the NMJ

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

-Ach binds to the alpha units of the receptor, this prompts the channel to open → Na+ and Ca+2 enter the cell, K+ exits the cell

What is the lethal triad of trauma?

-Acidosis -Hypothermia -Coagulopathy

Describe the physiologic changes that occur as a result of massive transfusion in the neonate/infant.

-Acidosis from inadequate oxygenation and increased serum lactate -Alkalosis from citrate metabolism to bicarbonate in the liver -Hypothermia from transfusion of cold blood -Hyperglycemia from dextrose additive in stored blood -Hypocalcemia from binding of calcium by citrate -Hyperkalemia from administration of older blood → The risk is reduced by administering washed or fresh cells that are less than 7 days old

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

-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 (this makes the cell more positive) -Once the threshold potential is achieved, the cell depolarizes and propagates an action potential. -Depolarization is an all or none phenomenon -The action potential only travels in one direction

Regarding the intrinsic pathway: -What activates it? -What lab tests measure it? -What drug inhibits it?

-Activated by blood injury or exposure to collagen -Measured by the PTT and ACT -Inhibited by heparin

Regarding the extrinsic pathway: -What activates it? -What lab tests measure it? -What drug inhibits it?

-Activated by vascular injury -Measured by the PT and INR -Inhibited by coumadin

How does nitrous oxide (by itself) affect hemodynamics?

-Activates the SNS → Increased SVR and MAP -N2O is also a myocardial depressant, but the increased SNS stimulation outweighs this

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

-Acute → non-emergent surgery should be postponed until symptoms have resolved and LFT return to normal -Chronic → Patient may proceed as long as condition is stable -Goals → preserve hepatic blood flow and avoid drugs that can potentiate hepatocellular injury

During endocascular coil placement for a cerebral aneurysm, the aneurysm ruptures. -What is the best treatment at this time?

-Administer protamine - 1 mg/100 units heparin administed -Lower MAP to low/normal range -Adenosine can be given to arrest the heart so the radiologist can control the bleeding

What is an acceptable urine output in a burned patient? -Is this different in children or patients who've suffered a high voltage electrical injury?

-Adult = > 0.5 mL/kg/hr -Child = > 1 mL/kg/hr -High voltage electrical injury = > 1-1.5 mL/kg/hr *Myogobinemia is the result of extensive muscle damage following a high voltage electrical injury

Contrast the laryngeal position in adults and infants.

-Adult = C5-C6 -Infant = C3-C4 -Larynx is more superior/cephalad, but NOT anterior. The only time the infant's airway is more "anterior" is during neck flexion -Same position as adult at age 5-6 years

Contrast the narrowest point of the airway in adults and infants.

-Adult = Glottis (vocal cords) -Infant = Cricoid or glottis* *Resistance to ETT insertion beyond the vocal cords is at the cricoid ring. Cricoid tissue is prone to inflammation and edema formation

Contrast the epiglottis shape in adults and infants.

-Adult = Leaf (C shape), floppier, shorter -Infant = U (omega shape), stiffer, longer

Contrast the orientation of the right mainstream bronchus in adults and infants.

-Adult = More vertical -Infant = Less vertical -Up to age 3, both bronchi take off at 55 degrees -In the adult, the right bronchus takes off at 25 degrees, and the left at 45 degrees

Contrast the relative size of the tongue in adults and infants.

-Adult = Small relative to oral volume -Infant = Large relative to oral volume -Tongue is closer to the soft palate in infants, which makes it more likely to obstruct the upper airway and more difficult to displace during laryngoscopy

Contrast the optimal intubation position for adults and infants.

-Adult = Sniffing position -Infant = Head on bed with shoulder roll (large occiput)

Contrast the breathing pattern in adults and infants.

-Adult = mouth or nose -Infant = Preferential nose breather for up to 5 moms of age -Infants convert to oral breathing if nasal passages are obstructed -Bilateral china atresia may require emergency airway management if the infant is unable to mouth breathe

Why does HgbF have a higher affinity for O2?

-Adult Hgb consist of 2 alpha and 2 beta chains -Fetal Hgb consist of 2 alpha and 2 gamma chains -The beta chains are the binding site for 2,3 DPG → Infants don't have these beta chains so they can't bind 2,3 DPG

Contrast the relative neck length in adults and infants.

-Adults = Longer -Infant = Shorter

Contrast the vocal cord position in adults and infants.

-Adults = Perpendicular to trachea -Infant = Anterior slant - passage of ETT may be more difficult

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

-Affinity for voltage-gated sodium channel in the active and inactive state -Rate of dissociation from the receptor during diastole -Essentially more bupivicaine remains at the receptor for a longer period of time Difficulty of cardiac resuscitation - bupivacaine > levobupivacaine > ropivacaine > lidocaine

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

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

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

-Afterload is the force the ventricle must overcome to eject its stroke volume -SVR is a surrogate for LV afterload

What are the risk factors for postintubation laryngeal edema?

-Age < 4 years -ETT too large -ETT cuff volume to high -Traumatic or multiple intubation attempts -Prolonged intubation -Coughing -Head or neck surgery -Head repositioning during surgery -History of infectious or post-intubation croup -Trisomy 21 -Upper respiratory tract infection

What are the risk factors for halothane hepatitis?

-Age > 40 years -Female -Greater than 2 exposures -Genetics -Obesity -CYP2E1 induction (alcohol, isoniazid, phenobarbital)

What factors reduce ventricular compliance?

-Age > 60 years -Ischemia -Pressure overload hypertrophy -Hypertropic obstructive cardiomyopathy -Pericardial pressure *Higher filling pressures are required to prime the ventricle

How do you treat intraoperative myocardial ischemia?

-Aim for interventions that make the heart slower, smaller, and better perfused.

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

-Albumin - Primarily binds to acidic drugs. However, it also binds to some neutral and basic drugs -Alpha-1-acid glycoprotein - Binds to basic drugs -Beta-globulin: Binds to basic drugs

What is the treatment for Conn's syndrome?

-Aldosterone antagonists → spironolactone or eplerenone -K+ supplementation -Na+ restriction -Removal of aldosterone-secreting tumor

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

-Aldosterone controls extracellular fluid volume (Na+ and water are reabsorbed together) -Antidiuretic hormone (vasopressin) controls plasma osmolarity (water is reabsorbed but Na+ is not) -The kidneys also regulate potassium, chloride, phosphate, magnesium, hydrogen, bicarbonate, glucose, and urea

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 principle cells of the distal tubules and collecting ducts, aldosterone causes: -Na+ reabsorption -Water reabsorption -K+ excretion -The net effect is that aldosterone increases blood volume but it does NOT affect osmolarity.

How does the ionization characteristics of alfentanil influence its onset of action?

-Alfentanil's pKa is 6.5, it is 90% unionized -It also has a low Vd, more drug available to enter the brain

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 physiologic disturbances result from massive transfusion?

-Alkalosis from citrate metabolism to bicarbonate in the liver -Hypothermia from cold blood -Hyperglycemia from dextrose additive in stored blood -Hypocalcemia from binding of Ca+2 by citrate -Hyperkalemia from administration of older blood

What plasma proteins are produced by the liver?

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

What does Reynold's number tell you?

-Allows us to predict the type of flow that will occur -Re < 2000 → laminar flow dependent on gas viscosity -Re > 4000 → turbulent flow dependent on gas density -Re 2000-4000 → transitional flow

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

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

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

-Alpha-1-acid glycoprotein increase -Albumin production decreases -Pseudocholinesterase production decreases

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

-Alpha-stat: Does not correct for patient's temperature, associated with better outcomes in adults -pH-stat: Corrects for patient's temperature, associated with better outcomes in pediatrics

What is CATCH 22?

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

How do changes in radius affect laminar flow (x2, x3, x4, and x5)

-Altering the radius of the tube exhibits the greatest impact on flow -x2 = 16x change -x3 = 81x change -x4 = 256x change

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

Describe the hemodynamic management of the patient with pheochromocytoma.

-Always alpha-block before you beta-block* -Non-selective alpha antagonists: phenoxybenzamine and phentolamine -Alpha-1 selective antagonists: doxazosin and prazosin

Discuss 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 the Kreb's cycle to produce ATP -The deamination process produces a large quantity of ammonia → the liver converts ammonia to urea -Failure to clear ammonia leads to hepatic encephalopathy

Which antibiotics are nephrotoxic?

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

What neuromuscular blockers can be reversed by sugammandex?

-Aminosteroidal neuromuscular blockers -rocuronium > vecuronium > pancuronium

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 -Lecithin to sphingomyelin (L/S ratio) > 2 suggests adequate lung development

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

-Amygdala -Hippocampus

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

-Amyotrophic lateral sclerosis -Charcot-Marie-Tooth -Duchenne's muscular dystrophy -Guillain-Barre -Hyperkalemic periodic paralysis -Multiple sclerosis -Upregulation of extrajunctional receptors

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

Where should an axillary roll be placed for the patient in the lateral decubitus position?

-An axillary role is placed distal to the axilla -A roll placed inside the axilla can cause neuromuscular compression *A poor SpO2 signal in the dependent arm is a good monitor for this

How do you perform an epidural blood patch? -What is the success rate?

-An epidural blood patch is the definitive treatment for PDPH and each patch is associated with a 90% success rate. If the H/A does not improve after 2 blood patches, other etiologies should be sought -Using sterile technique, 10-20 mL of venous blood is withdrawn from he patient and then reintroduced into the epidural space. When the patient senses pressure in her legs, buttocks, or back, the injection is complete. A blood patch is useful for 2 reasons: 1. It compresses the epidural and subarachnoid spaces, which increases CSF pressure 2. It acts as a plug that prevents further leaks.

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

-An increased alpha angle signifies an expiratory airflow obstruction, such as COPD, bronchospasm, or a kinked ETT -The beta angle is increases in some etiologies of rebreathing

How does dexmedotomidine produce analgesia?

-Analgesia is produced by alpha-2 stimulation in the dorsal horn of the spinal cord → decreased substance P and glutamate release

Define the 4 types of dead space

-Anatomic Vd: Air confined to the conducting airways -Alveolar Vd: Alveoli that are ventilated but not perfused -Physiologic Vd: Anatomic Vd + Alveolar Vd -Apparatus Vd: Vd added by equipment

How do you block the radial nerve at the wrist?

-Anatomic landmark → Radial styloid -Field block of 10 mL of LA proximal to the radial styloid

How do you block the median nerve at the wrist?

-Anatomic landmarks → Flexor carpi radialis tendon, flexor palmaris longus tendon -Inject 5 mL of LA between the flexor carpi radialis tendon and the flexor palmaris longus tendon

How do you block the ulnar nerve at the wrist?

-Anatomic landmarks → Ulnar styloid, ulnar pulse, flexor carpi ulnaris tendon -Inject 3-5 mL of LA medial and below the flexor carpi ulnaris tendon

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

-Anterior and posterior circulations converge at the circle of Willis -Anterior internal carotid arteries supply the anterior circulation -Aorta → carotid a. → internal carotid a. → Circle of Willis → cerebral hemispheres -The vertebral arteries supply the posterior circulation -Aorta → subclavian a. → vertebral a. → basilar a. → posterior fossa structures and cervical spinal cord

Where is the superficial peroneal nerve blocked?

-Anterior to the lateral malleolus

Where is the saphenous nerve blocked?

-Anterior to the medial malleolus

What drugs can potentiate the effects of neuromuscular blockers?

-Antibiotics -Antidysrhythmics -Local anesthetics -Diuretics -Others

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

What drugs and conditions should be avoided in the patient with acute intermittent porphyria? -Why?

-Any drug or condition that induces ALA synthase will accelerate the production of heme precursors -Drugs to avoid: Barbiturates, etomidate, glucocorticoids, hydralazine -Conditions to avoid: Emotional stress, prolonged NPO status, hypothermia

Explain the Venturi effect and give some examples.

-Application of the Bernoulli principle -As air flow in a tube moves past the point of constriction, the pressure at the constriction decreases. If the pressure inside the tube falls below atmospheric pressure, then air is entrained into the tube -Examples → jet ventilator, venturi, and nebulizer

How does arterial compliance change in the elderly?

-Arterial compliance decreases as a function of loss of elastin and increased collagen. -Increased SVR → increased BP -Increased pulse pressure -Increased Myocardial wall tension to overcome high after load -Eccentric hypertrophy

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

-As the atmospheric pressure decreases at higher elevations, the volume% of gas remains the same, but the partial pressure decreases. -Under-dosing with desflurane (not sevo or iso) is a problem at elevation because the injector design of the Tec 6 vaporizer does not compensate for elevation

Which position is most likely to cause midcervical tetraplegia?

-Associated with hyper flexion of the neck (chin to chest). Ischemia occurs as a result of stretching and/or compression of the midcervical spinal cord (usually C5) -Most common in the sitting position -You should be able to place at least 2 fingers in between the chin and the chest

Define Henry's law. List several examples of how it can be used in the operating room.

-At a constant temperature, the amount of gas that dissolves in solution is directly proportional to the partial pressure of that gas over the solution. -The higher the gas pressure, the more of it will dissolve into a liquid -Anesthetic emergence is prolonged in the hypothermic patient -Dissolved oxygen in the oxygen carrying capacity equation.

What is the most common airway complication of rheumatoid arthritis? -What is its clinical significance?

-Atlantoaxial subluxation due to the weakening of the transverse axial ligament

Which antimuscarinics pass through the blood brain barrier? -Which do not? Why?

-Atropine and scopolamine are naturally occurring tertiary amines → they easily cross the BBB, GI tract, and placenta -Glycopyrrolate is different, as a quaternary ammonium derivative, it is ionized → does not cross the BBB, GI tract, or placenta

Discuss the differential blockade of spinal anesthesia.

-Autonomic fibers blocked first, sensory fibers blocked second, motor neurons are blocked last -Autonomic blockade is 2-6 dermatomes higher than sensory -Sensory block is 2 dermatomes higher than the motor block

Describe the autonomic influence on the newborns heart.

-Autonomic regulation of the heart is immature at birth, with the SNS being less mature than the PNS. Stressful situations such as laryngoscopy and suction of the airway 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

What drugs should be avoided in the patient with each type of familiar periodic paralysis? -How about temperature?

-Avoid hypothermia for both forms of the disease -Acetazolamide is the treatment for both forms of the disease

How can you reduce the risk of airway complications while anesthetizing a child with an upper respiratory infection?

-Avoid mechanical irrigation of the airway: Facemask > LMA >> ETT -ETT use increases the risk of bronchospasm 10-fold -If an ETT must be used, use a smaller size -Dexamethasone 0.25-0.5 mg/kg -Ensure a deep plane of anesthesia before instrumenting the airway -Propofol may reduce the risk of bronchospasm -Sevoflurane is the best volatile agent *Pretreatment with a bronchodilator or glycopyrrolate does not provide a clear benefit

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

-Awake nasal intubation or awake tracheostomy

How does 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

What is included in the differential diagnosis of a low BUN? -How about a high BUN?

-BUN is a better indicator of uremic symptoms than a measurement of GFR

What is the BUN:Creatinine ratio? -What do the numbers mean?

-BUN undergoes filtration AND reabsorption -Creatinine undergoes filtration but not reabsorption -The ratio of these substance can help us evaluate the state of hydration -Normal ratio = 10:1 -BUN:Cr ratio of > 20:1 suggest prerenal azotemia -Non-renal causes of elevated BUN can also affect this ratio

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

-BUN → 10-20 mg/dL -Serum creatinine → 0.7-1.5 mg/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 -Normal response: Downward motion of all the toes -Upper motor neuron injury: Upward extension of the big toe with fanning of the others -Lower motor neuron injury: No response

Explain how understanding Reynold's number helps you treat status asthmatics.

-Because turbulent flow is dependent on gas density, we can improve flow by having the patient inhale a lower density gas -An oxygen/helium mixture improves Reynold's number by reducing density -We are converting turbulent flow to laminar flow

What is Beck's triad? -What conditions are associated with it?

-Becks triad occurs in patients with acute cardiac tamponade -S/Sx: Hypotension, JVD, Muffled heart tones

How do you treat PDPH?

-Bed rest -Hydration -NSAIDs -Caffeine -Epidural blood patch -Opioids are not used to treat PDPH

Discuss 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.

How does pregnancy affect gastric emptying?

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

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

-Below the fistula, but above the carina

Which class of neuromuscular blockers provides the most predictable duration of action in patients with chronic kidney disease?

-Benzoquinolines → cisatracurium and atracurium

Discuss the metabolism of the benzylisoquinolinium neuromuscular blockers.

-Benzylisoquinolinum compounds undergo spontaneous degradation in the plasma → not dependent on hepatic or renal function -Atracurium → hydrolyzed by Hofmann elimination (33%) and non-specific plasma esterases (66%) -Cisatracurium → Hofman elimination only -Mivacurium → metabolized by pseudocholinesterase (same as Sch)

What does the alveolar compliance curve tell you?

-Best ventilated alveoli are the most compliant (steep portion of the curve) -Poorest ventilated alveoli are the least compliant (flat portion of the curve)

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

-Beta blockers that exert a partial agonist effect, while simultaneously blocking other agonists that have a higher affinity for the beta receptor -Ex: Labetalol and pindolol

What are the side effects of beta-2 agonists when used for tocolysis?

-Beta-2 agonists: Terbutaline, Ritodrine Side effects -Hypokalemia from intracellular K+ shift -May increase FHR (cross placenta) -Hyperglycemia from glycogenolysis in the liver *The newborn of a hyperglycemic mother is at risk of post-delivery hypoglycemia. The mother's glucose supply is gone, but the insulin in the neonatal circulation remains

What are problems that can arise if you beta-block before alpha-block with a pheochromocytoma?

-Beta-2 blockade inhibits skeletal muscle vasodilation and increases SVR -Beta-1 blockade reduces inotropy and can precipitate CHF in the setting of increased SVR

Describe the autonomic innervation of the bronchial tree.

-Beta-2 receptors are not innervated. Instead, they respond to catecholamines in systemic circulation

Where is the deep peroneal nerve blocked?

-Between the tendons of the anterior tibial and extensor digitorum longs muscles

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

-Bilateral = Hoarseness/No respiratory distress -Unilateral = No respiratory distress

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

-Bile is produced by the hepatocytes -The canaliculi drain bile into the bile duct -The bile ducts converge to form the common hepatic duct -The cystic duct (from the gallbladder) and the pancreatic duct join the common hepatic duct before it empties into the duodenum. -The spinchter of Oddi controls the flow of bile released from the common hepatic duct. -Contraction of the sphincter of Oddi (narcotics) increases biliary pressure

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 is the mechanism of action of NK-1 antagonists? Give an example of a drug in this class.

-Block substance P in the chemoreceptor trigger zone -Ex: Aprepitant

List several examples of how Boyle's law can be applied in the operating room.

-Boyle's law (P x V) -Diaphragm contraction increases tidal volume -Pneumatic bellows -Squeezing an Ambu bag -Using the bourdon pressure gauge to calculate how much O2 is left in a cylinder

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

Know the temperature conversion formulas.

-C = K - 273.15 -K = C + 273.15 -C = (F-32) x 5/9 -F = (C x 1.8) + 32

Which hormone stimulates bile release? -What is the stimulus for release?

-CCK stimulates gallbladder contraction and increases the flow of bile into the duodenum -Production and release = duodenum -Release due to food ingestion and increased vagal stimulation

Wha is the normal value for CMRO2? -What factors cause it to increase and decrease?

-CMRO2 describes how much O2 the brain consumes per minute -Normal CMRO2 → 3.0-3.8 mL/O2/100g/min -Decreaed by hypothermia (7% per 1 degree decrease), halogenated anesthetics, propofol, etomidate, and barbiturates -Increased by hyperthermia, seizures, ketamine, and N2O

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

-CMV (1-3% of transfusions) -Hepatitis B -Hepatitis C -HIV

Which cranial nerve resides in the CNS? -What is the implication of this?

-CN II - Optic nerve, is the only cranial nerve that is part of the CNS -Because it is part of the CNS, it is bathed in CSF → can be blocked

Discuss the clinical considerations for the patient with carbon monoxide poisoning.

-CO binds to Hgb with an affinity 200x that of O2 -CO shifts the oxyhemoglobin dissociation curve to the left -Inadequate oxygen delivery causes metabolic acidosis -Blood takes on cherry red appearance -Pulse oximeter is not accurate, a co-oximeter is needed -Treatment: 100% FiO2 or hyperbaric oxygen

What color goggles must be worn for each type of laser: CO2, Nd:YAG, Ruby, Argon

-CO2 = Clear -Ruby = Red -Argon = Amber -Nd:YAG = Green

Discuss the role of the cyclooxyrgenase enzyme in the arachidonic acid cascade.

-COX-1 is always present, it maintains normal physiologic function -Inhibition of the COX-1 enzyme impairs platelet function, causes gastric irritation, and reduces renal blood flow -COX-2 is not always present, it is expressed during inflammation -Inhibition of the COX-2 enzyme produces analgesic, anti-inflammatory, and antipyretic effects. There is a ceiling to analgesic effects

What is the equation for coronary perfusion pressure?

-CPP = Aortic DBP - LVEDP -CPP can be improved by increasing AoDBP or decreasing LVEDP

What is the formula for cerebral perfusion pressure? -What is normal?

-CPP = MAP - ICP (or CVP, whichever is higher) -Cerebral vasculature auto regulates to provide a constant CPP of 50-150 mmHg *MAP must be 60-65 mmHg to maintain autoregulation

What is the function of CSF? -Where is it located?

-CSF cushions the brain, provides buoyancy, and delivers optimal conditions for neurologic function -It is located in the ventricles, cisterns around the brain, and subarachnoid space in the brain and spinal cord

Describe the production, circulation, and absorption of CSF.

-CSF production → Ependymal cells of the chorioid plexus at a rate of 30 mL/hr -Circulation - *pneumonic → Love My 3 Silly 4Lorn Magpies -Reabsorption → Venous circulation via the arachnoid villi in the superior sagittal sinus

What is the normal volume and specific gravity of CSF?

-CSF volume → 150 mL -CSF specific gravity → 1.002 - 1.009

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

-CYP inhibition -Because theophylline has a low hepatic extraction ratio, prolonged hypotension will not impact its rate of metabolism like CYP inhibition will

What is calcitriol and what does it do?

-Calciferol is synthesized from ingested vitamin D or following exposure to ultraviolet light -Calciferol is converted to vitamin D3 in the liver -Vitamin D3 is 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

List all the treatment options for hyperkalemia.

-Calcium -Insulin + D50 -Hyperventilation -Bicarbonate -Albuterol -Potassium wasting diuretics -Dialysis

How can oxytocin be administered? -What are the potential side effects?

-Can be given IV or the OB can inject it directly into the uterus Side effects -Water retention -Hyponatremia -Hypotension -Reflex tachycardia -Coronary vasoconstriction

Describe the presentation of thyroid storm.

-Can occur in hyperthyroid AND euthyroid patients -Brought on by stressful events -Most commonly occurs 6-18 hours after surgery

Regarding hepatic clearance, what is capacity-limited elimination?

-Capacity Limited Elimination (ER < 0.3) -Low hepatic extraction ratio, 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 clearance -Enzyme induction → Increased clearance -Enzyme inhibition → Decreased clearance

Discuss the pathophysiology of carbon monoxide poisoning. -How is it measured? What do patient's look like?

-Carbon monoxide reduces the O2 carrying capacity of blood. It binds to the oxygen binding site on hemoglobin with an affinity 200x that of oxygen -CO is measured with a co-oximeter -Patients appear cherry-red -SNS stimulation can be confused with light anesthesia or pain

Describe the pathophysiology of pericardial tamponade.

-Cardiac tamponade occurs when fluid accumulates inside the pericardium. What separates it from a pericardial effusion is that excess fluid exerts an external pressure on the heart, limiting its filling ability. -CVP rises in tandem with pericardial pressure. As ventricular compliance deteriorates, CVP and PAOP begin to equalize -Diagnosis → TEE -Treatment → Pericardiocentesis or pericardiostomy

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

-Cardiac troponin are more sensitive than CK-MB for the diagnosis of MI

How do you manage the patient with thyroid storm?

-Cardiopulmonary support -Active cooling measures -PTU or methimazole -Beta-blockers -Acetaminophen for fever -Avoid aspirin

List 6 non-selective beta antagonists.

-Carvedilol -Labetalol -Nadolol -Pindolol -Propranolol -Timolol

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

In which regions of the brain do halogenated anesthetics produce unconsciousness?

-Cerebral cortex -Thalamus -Reticular activating system

What is the most significant source of morbidity and mortality in the patient with SAH?

-Cerebral vasospasm is delayed contraction of the cerebral arteries. It can lead to cerebral infarction and is the most significant source of morbidity and mortality in the patient with SAH. -Positive correlation between the amount of blood observed on a CT and the incidence of vasospasm.

What regional technique can be used for the patient undergoing carotid endarterectomy? -What levels must be blocked?

-Cervical plexus block (superficial or deep) -Local infiltration -Regional anesthesia must cover C2 - C4

What is truncus arteriosus?

-Characterized by a single artery that gives rise to the pulmonary, systemic, and coronary circulations. -With only one artery, there is no specific pathway for blood to enter the pulmonary circulation -Usually a VSD as well -Decreasing PVR or increasing pulmonary flow steals blood from systemic and coronary circulations

What is familial periodic paralysis and how can the 2 variants of this disease be distinguished from each other?

-Characterized by acute episodes of skeletal muscle weakness that is accompanied by either hypo or hyperkalemia -Hypokalemic periodic paralysis → Diagnosed if skeletal muscle weakness follows a glucose-insulin infusion. The patient becomes weak after the serum K+ is reduced -Hyperkalemic periodic paralysis → Diagnosed if skeletal muscle weakness follows oral potassium administration, the patient becomes weak after the serum K+ is increased

Describe the pathophysiology of disseminated intravascular coagulation.

-Characterized by disorganized clotting and fibrinolysis that lead to the simultaneous occurrence 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 the widespread consumption of its coagulation factors, fibrinogen, and platelets

List several examples of how Charles's law can be applied in the operating room.

-Charles's law (V / T) -LMA cuff ruptures when placed in an autoclave

What is Medndelson's syndrome?

-Chemical aspiration pneumonitis -Risk factors: Gastric pH < 2.5, Gastric volume > 25 mL (0.4 mL/kg)

List 5 indications for the use of a bronchial blocker.

-Children < 8 years -Require nasotracheal intubation -Have a tracheostomy -Have a single lumen ETT in place -Require intubation after surgery and you want to avoid changing the DLT to a single-lumen ETT at the end of the case

What is an enantiomer? What is the clinical relevance?

-Chiral molecules that are non-superimposable mirror images of one another -Different enantiomers can produce different clinical effects

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

What is the best way to prepare the skin prior to neuraxial anesthesia?

-Chlorhexidine, isopropyl alcohol, and iodine solutions -The best method is a combination of chlorhexidine + isopropyl alcohol -Chlorhexidine is neurotoxic, so it's imperative that you allow it to dry completely before you penetrate the skin with the needle

What class of drugs is used to treat Alzheimer's disease? -How do they interact with succinylcholine?

-Cholinesterase inhibitors → tacrine, donepezil, rivastigmine, galantamine -These drugs increase the duration of action of Sch

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.

Define the following terms: -Chronotropy -Inotropy -Dromotropy -Lusitropy

-Chronotropy: Heart rate -Inotropy: Strength of contraction (contractility) -Dromotropy: Conduction velocity (how fast the action potential travels per time) -Lusitropy: Rate of myocardial relaxation (during diastole)

Describe the anatomy of the circle of Willis.

-Circle of Willis functions to provide redundancy of blood flow in the brain

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 cirrhosis?

-Cirrhosis is characterized by cell death, where healthy hepatic tissue is replaced by nodules and fibrotic tissue. This reduces the number of functional hepatocytes as well as the number of sinusoids

Rank the non depolarizing neuromuscular blockers in terms of ED95 (lowest to highest).

-Cisatracurium -Vecuronium -Mivacurium = Pancuronium -Atracurium -Rocuronium *Dose required to provide optimal conditions for tracheal intubation is 2-3x the ED95

Name 4 substances that extend the shelf life of RBCs. What is the function of each?

-Citrate: An anticoagulant that inhibits calcium. After transfusion of multiple units, the citrate load can cause hypocalcemia -Phosphate: Buffer that combats acidosis -Dextrose: Primary substrate for glycolysis -Adenine: Substrate that helps RBCs re-sythessize ATP, extends storage time from 21 to 35 days

What is the Modified New York Association Functional Classification of Heart Failure?

-Class I: Asymptomatic -Class II: Symptomatic with moderate activity -Class III: Symptomatic with mild activity -Class IV: Symptomatic at rest

Discuss the presentation and pathophysiology of autonomic hyperreflexia.

-Classic presentation is HTN and bradycardia -Reflex vasodilation above the level of the spinal cord injury → nasal stuffiness -H/A and blurred vision

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 for fetal pH in healthy mothers

What is the relationship between neuraxial anesthesia and multiple sclerosis?

-Classic teaching suggests that, while epidural anesthesia is safe, an intrathecal technique may exacerbate symptoms. There is no good data to support this, however. -If a spinal anesthetic would benefit the patent with MS, then the patient should be informed that there may be a small risk of symptom exacerbation.

What is clearance? -What factors increase/decrease it?

-Clearance is the volume of plasma that is cleared of drug unit per time

What drugs can be added to local anesthetics to provide supplemental analgesia? -What is the mechanism of action for each one?

-Clonidine (alpha-2 agonist) -Epinephrine (alpha-2 agonist) -Opioids (mu against)

List 4 examples of ADP receptor inhibitors, and state how long each must be discontinued prior to surgery.

-Clopidogrel → 7 days -Ticlopidine → 14 days -Prasugrel → 2-3 days -Ticagrelor → 1-2 days

How do you treat the patient with an intracerebral bleed who is on clopidogrel?

-Clopidogrel, aspirin, or both can be reversed with a platelet transfusion or factor VIIa.

What drugs can be used to close the ductus arteriosus? -Which can be used to open it?

-Closed with indomethacin -Opened with PGE1

What is closing volume and what increases it?

-Closing volume is the point at which dynamic compression of the airways begins. -The volume above residual volume where the small airways being to close during expiration. Increased - pneumonic CLOSE-P -COPD -Left ventricular failure -Obesity -Smoking -Extreme age -Pregnancy

Under normal conditions, why does blood remain a liquid?

-Coagulation proteins circulate in an inactive form -The endothelium is smooth and the glycocalyx repels clotting factors -Undamaged endothelium does not express tissue factor or collagen. This prevents activation of platelets and the coagulation cascade -Activated factors are removed by brisk blood flow through the vessels as well as anticoagulants in circulation

What are the indications for FFP transfusion?

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

List 6 causes of secondary hypertension.

-Coarctation of the aorta -Renovascular disease -Hyperadrenocorticism (Cushing's syndrome) -Hyperaldosteronism (Conn's disease) -Pheochromocytoma -Pregnancy-induced HTN

What is 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

Discuss the FDA recommendations for the minimum fresh gas flow requirement for sevoflurane?

-Compound A is a halogenated vinyl ether. It is associated with renal tubular necrosis in rats → No supporting literature in humans -Minimum FGF of 1L/min for up to 2 MAC hours and 2 L/min after 2 MAC hours

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

-Conduction velocity is a measure of how fast an axon transmits the action potential CV is increased with: -Myelination (AP skips along the nodes of Ranvier - saltatory concussion) -Large fiber diameter

A patient has a hernia at the foramen of Bochdalek. Which congenital condition does this patient have?

-Congenital diaphragmatic hernia → allows the abdominal contents to enter the thoracic cavity -Foramen of Bochdalek is the most common side of herniation (left side) -Diagram is from the abdomen looking up towards the thorax

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

-Conn's syndrome = Too much aldosterone -Primary - Increased aldosterone release from adrenal gland -Secondary - Usually due to increased renin release or aldosterone-secreting tumor -Hypertension (Na+ and water retention) -Hypokalemia (K+ wasting) -Metabolic alkalosis (K+ wasting)

Discuss the pathophysiology and treatment of flail chest.

-Consequence of blunt chest trauma with multiple rib fractures - paradoxical movement of the chest wall at the site of the fractures -Flail chest will move inward and collapse the affected region on inspiration, move outward and affected region doesn't empty on expiration -Treatment: Epidural catheter or intercostal nerve blocks

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

-Consider aspiration prophylaxis if mom is beyond 14 weeks gestation -Administer an antacid (sodium citrate 15-30 mL) within 30 minutes of induction, ranitidine 1 hour prior to induction, and consider metoclopramide to facilitate gastric emptying -If mom is beyond 14 weeks gestation, secure the airway with a RSI and a 6.0-7.0 ETT

Describe the pathophysiology of constrictive pericarditis.

-Constrictive pericarditis is caused by fibrosis or any condition where the pericardium becomes thicker -During diastole, the ventricles cannot fully relax, and this reduces compliance and limits diastolic filling. Ventricular pressures increase, which creates a back pressure to the peripheral circulation. -Ventricles adapt by increasing myocardial mass, but this impairs systolic function

How do opioids affect biliary pressure, gastric emptying, and peristalsis?

-Contraction of sphincter of Oddi → increased biliary pressure (reversed with naloxone or glucagon) -Prolonged gastric emptying -Slowed peristalsis → constipation

What is the treatment for postintubation laryngeal edema?

-Cool and humidified O2 -Nebulized racemic epinephrine → 0.5 of 2.25% solution in 2.5 mL of 0.9% NaCl -Dexamethasone 0.25 - 0.5 mg/kg IV -Heliox is a helium + oxygen mixture that improves laminar airflow by reducing Reynold's number -Patient should be observed for a minimum of 4 hours after the racemic epinephrine treatment is complete

What is strabismus correction? -What unique considerations apply to the anesthetic management of these patients?

-Corrects the misalignment of the extraoculasr muscles and re-establish the visual axis. -Increased risk of malignant hyperthermia -Increased risk of PONV -Increased risk of activating the oculocardiac reflex

Discuss the use of steroids and tocolytic agents in the prevention of premature delivery.

-Corticosteroids (betamethasone) hasten fetal lung maturity. These drugs begin to take effect within 18 hours, with peak benefit at 48 hours -Tocolytic agents stop labor for about 24-48 hours. They provide a bridge that allows the corticosteroids time to work. Antibiotic prophylaxis for chorioamnionititis is also given at this time -Tocolytic agents or corticosteroids are seldom given after 33 weeks

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 -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 or acute adrenal failure) -Mortality may be increased with etomidate (particularly with sepsis)

How does cortisol affect cardiovascular function?

-Cortisol improves myocardial performance by increasing the number and sensitivity of beta receptors on the myocardium -Cortisol is also required for the vasculature to respond to the vasoconstrictive effects of catecholamines

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

-Cortisol production is 15-30 mg/day with a normal serum level of 12 mcg/dL -Stress can increase cortisol production upwards of 100 mg/day with a serum level of up to 30-50 mcg/dL

How can you tell the difference between chemical structures of the halogenated agents?

-Count the halogens -Isoflurane → 5 fluorine atoms + 1 chlorine atom -Desflurane → 6 fluorine atoms -Sevoflurane → 7 fluorine atoms

What test is the best indicator of GFR? -How is this value calculated?

-Creatinine clearance is the best determinant of GFR

-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 VIII, XIII, fibrinogen, and vWF. It can be used for type I, II, or III disease. -FFP → contains all of the clotting factors, so it too can be used for type I, II, or III disease -Purified VIII-vWF concentrate → reduces the risk of transfusion related infection, first-line agent for the patient with type III disease

Define Ohm's law.

-Current passing through a conductor is directly proportional to the voltage and inversely proportional to the resistance. We can adapt Ohm's law to understand fluid flow

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

-Cushing's syndrome → Too much cortisol -Cushing's disease → Too much ACTH

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

-Cytomegalovirus -Leukoreduction greatly reduces this risk

What is the treatment for intraoperative anaphylaxis?

-D/C offending agent -Airway support → 100% FiO2 -Epinephrine → 5-10 mcg for hypotension, 100 mcg - 1 mg for CV collapse -Liberal IV hydration → crystalloid 10-25 mL/kg -H1 and H2 receptor antagonists → diphenhydramine and ranitidine/famotidine -Hydrocortisone 250 mg IV -Albuterol for bronchospasm -Vasopressin for refractory hypotension

How do you treat MH?

-D/C triggering agent -Administer 100% O2 at > 10L/min -Administer dantrolene 2.5 mg/kg IV and repeat q5-10 minutes -Hyperventilate -Correct lactic acidosis with sodium bicarbonate -Treat hyperkalemia with Ca+2, dextrose/insulin -Protect against dysrhythmias -Maintain urine output -Cool the patient until the temperature drops below 38 degrees C -Monitoring coagulation

Compare and contrast the location and function of dopamine-1 and dopamine-2 receptors.

-DA1 receptors are present in the kidney and the splanchnic circulation -DA2 receptors are present on the presynaptic adrenergic nerve terminal

What is the mechanism of action of desmopressin? -What is the dose?

-DDAVP is a synthetic analogue of antidiuretic hormone. It stimulates the release of endogenous vWF and increases factor VIII activity -Patients with Type I disease respond best to desmopressin -Patients with Type III disease do not respond to DDAVP because they do not produce vWF -Dose = 0.3-0.5 mcg/kg -Side effect = hypotension with rapid administration

What does the diffusing capacity for carbon monoxide tell us?

-DLCO is used to assess how well the lung can exchange gas -Normal = 17-25 mL/CO/min/mmHg -Using Fick's law of diffusion, this tells us 2 key characteristics about the alveolar-capillary interface - surface area and thickness -DLCO is reduced by anything that reduces alveolar surface area (emphysema) and/or increases the thickness of the alveolar capillary interface (pulmonary fibrosis and pulmonary edema)

How does dantrolene treat MH? -What are its most common side effects?

-Dantrolene is classified as a muscle relaxant -It halts Ca+2 release from the RyR1 receptor -It prevents Ca+2 entry into the myocyte which reduces the stimulus for Ca+2-induced-Ca+2-release -The most common side effects are muscle weakness and venous irritation

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 -Altered baroreceptor function

Discuss the RBC storage lesion.

-Decreased 2,3 DPG → shifts oxyhemoglobin dissociation curve to the left -Decreased ATP → shift to anaerobic metabolism -Decreased pH → increased lactic acid -Increased potassium -Impaired ability to change shape → important for capillary flow -Hemolysis -Increased production of pro inflammatory mediators

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

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

-Decreased PP binding → Increased Cp -Increased PP binding → Decreased Cp

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 (decreased baroreceptor function) -Impaired thermoregulation increases the risk of hypothermia

Why are patients with chronic kidney disease often anemic? -What is the treatment for this?

-Decreased erythropoietin production leads to a normochromic normocytic anemia -Excess PTH replaces bone marrow with fibrotic tissue Treatment: -Exogenous EPO + iron supplementation -Blood transfusion is not a first-line treatment

How does chronic kidney disease affect acid-base balance?

-Decreased excretion of non-volatile acid contributes to a gap metabolic acidosis -Gap acidosis is the result of an accumulation of non-volatile acids -Compensatory respiratory alkalosis

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, antibiotics, and reduced protein intake

What conditions impart the reliably of the pulse oximeter?

-Decreased perfusion -Dysfunctional Hgb (NOT HgbS or HgbF) -Altered optical characteristics (methylene blue) -Non-pulsatile flow -Motion artifact (shivering)

What conditions impair atlanto-occipital joint mobility?

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

What EKG findings are consistent with Wolff-Parkinson-White syndrome?

-Delta wave caused by ventricular pre excitation -Short PR interval -Wide QRS complex -Possible T wave inversion

Describe the Haldane effect.

-Describes CO2 carriage -Increased O2 causes the erythrocyte to release CO2

Describe the Bohr effect.

-Describes O2 carriage -Increased CO2 and Decreased pH cause the erythrocyte to release O2

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.

Describe Fick's law of diffusion.

-Describes the transfer rate of gas through a tissue medium

How does the intra-aortic balloon pump function throughout the cardiac cycle? -How does it help the patient?

-Diastole: Pump inflation augments coronary perfusion, inflation correlates with the dicrotic notch on the aortic pressure waveform -Systole: Pump deflation reduces after load and improves cardiac output, deflation correlates with R wave on the EKG -The IABP improves myocardial oxygen supply while reducing myocardial oxygen demand

Discuss differential blockade using epidural bupivacaine as an example

-Differential blockade: Some fiber types are blocked sooner than others Epidural bupivacaine -At lower concentrations, epidural bupivacaine provides analgesia while sparing motor function -As the concentration is increased, it anesthetizes more resistant nerve types, such as those that control motor function and proprioception

List clinical examples of Fick's law of diffusion.

-Diffusion hypoxia -A patient with COPD has a reduced alveolar surface area and therefore has a slower rate of inhalation induction -Calculation of cardiac output -Drug transfer across the placenta

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

-Diprivan contains EDTA - no issues -Metabisulfite can precipitate a bronchospasm in asthmatics -Benzyl alcohol should be avoided in infants

List 3 ways to protect yourself from radiation exposure.

-Distance -Duration -Shielding

What are the anesthetic implications of acromegaly.

-Distorted facial features (difficult mask) -Large tongue, teeth, and epiglottis (difficult DL) -Subglottic narrowing and vocal cord enlargement (smaller ETT) -Turbinate enlargement (avoid nasal intubation) -OSA is common -Increased risk of HTN, CAD, rhythm disturbances -Glucose interolernce -Skeletal muscle weakness and neuropathies

What is the treatment for hypermagnesemia?

-Diuresis -IV calcium

Why is dexmedomidine attractive for procedural sedation?

-Does not cause respiratory depression, this makes it attractive for procedural sedation and during difficult airway management -No change in oxygenation -No change in blood pH -No change in the slope of the CO2 response curve

How does the source of blood products affect the risk of TRALI?

-Donor groups with the highest risk of TRALI -Multiparous women (highest risk) -History of blood transfusion -History of organ transplant

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 Pairing: Glycopyrrolate

Regarding pyridostigmine, what is the dose, onset, duration, metabolism, and best antimuscarinic pairing?

-Dose: 0.1-0.3 mg/kg -Onset: 10-20 minutes -Duration: 60-120 minutes -Metabolism: 75% renal/25% hepatic -Best Pairing: Glycopyrrolate

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

Regarding edrophonium, what is the dose, onset, duration, metabolism, and best antimuscarinc pairing?

-Dose: 0.5-1 mg/kg -Onset: 1-2 minutes -Duration: 30-60 minutes -Metabolism: 75% renal/25% hepatic -Best Pairing: Atropine

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

-Dose: Adult = 2.5-5 mg/kg, Children = 5-6 mg/kg -Onset: 30-60 seconds -Duration: 5-10 minutes -Clearance: Liver (P450 enzymes) -Awakening is determined by redistribution (not metabolism) -Repeated doses → tissue accumulation → prolonged wake up and hangover effect

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

-Dose: Induction → 1.5-2.5 mg/kg, Infusion → 25-200 mcg/kg/min -Onset: 30-60 seconds -Duration: 5-10 minutes -Clearance: Liver (P450 enzymes) + extrahepatic metabolism (lungs)

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

-Dose: Loading = 1 mcg/kg over 10 minutes, Maintenance infusion = 0.4 - 0.7 mcg/kg/hr -Onset: 10-20 minutes -Duration: 10-30 minutes after infusion is stopped -Clearance: Liver (P450 enzymes)

Name 2 antiemetics that prolong the QT interval.

-Droperidol and ondansetron

How is potency measured on the dose-response curve?

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

What is the primary risk of neuraxial anesthesia in the anticoagulated patient? -How does this complication present?

-Drug block placement and catheter removal -Epidural hematoma can cause paralysis. Presenting symptoms include lower extremity weakness, numbness, low back pain, and bowel and bladder dysfunction. -Surgical decompression within 8 hours offers the best chance of recovery

Which drugs reduce aqueous humor production? -Which increase aqueous humor drainage?

-Drugs that decrease aqueous humor production → Acetazolamide, timolol -Drugs that increase aqueous humor drainage → Echothiophate

Why are the alcoholics susceptible to Wernicke-Kosakoff syndrome?

-Due to vitamin B1 deficiency -Wernicke-Korsakoff syndrome is characterized by a loss of neurons in the cerebellum, brought on by thiamine deficiency

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

-During retinal detachment surgery → N20 diffuses into the SF6 bubble and expands it → decreased retinal perfusion and blindness -D/C N2O 15 minutes before the bubble is placed and 7-10 days after the bubble is placed *Silicone oil has no contraindication to N2O

Describe the pathophysiology of Duchenne muscular dystrophy.

-Dystrophin is a critical structural component of the cytoskeleton of skeletal and cardiac muscle cells. It helps anchor actin and myosin to the cell membrane. The absence of dystrophin destabilizes the sarcolemma during muscle contraction and increases the membrane permeability. -The absence of dystrophin allows extrejunctional receptors to populate the sarcolemma. This predisposes these patients to hyperkalemia following Sch administration.

How do you calculate ejection fraction?

-EF: The percentage of blood that is ejected from the heart during systole -EF = (SV/EDV) x 100 -Normal EF = 60-70% -LV dysfunction present when EF < 40%

How does ESWL affect cardiac conduction? -What is done to minimize this risk?

-ESWL can produce dysrhythmias and the pulse wave is timed to the R wave on the EKG to minimize the risk of "R-on-T" phenomenon

Contrast the maximum recommended cuff pressures for an endotracheal tube vs. LMA.

-ETT < 25 mmHg -LMA < 60 mmHg

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

-Each one is a branch of either the femoral or sciatic nerves -The 3 sensory nerves begin with an "s", the 2 mixed nerves don't

How is dantrolene formulated? -How is it prepared?

-Each vial contains 20 mg dantrolene + 3 g of mannitol → the vial must be reconstituted with preservative free water -Warming the diluent can make the process much faster

What are the signs, symptoms, and treatment for alcohol withdrawal symptom?

-Early S/Sx → tremors and disordered perception -Late S/Sx → increased SNS activity -Treatment → alcohol, beta blockers, alpha-2 agonists

Which type of fetal decelerations are unremarkable?

-Early decelerations do not present a risk of fetal hypoxia

How does hyperkalemia affect the EKG (list the events in order of appearance)?

-Early: long PR, peaked T-wave, short QT -Middle: flat P-wave, wide QRS -Late: Sine wave QRS, VF

Describe the pathophysiology of Eaton-Lambert syndrome.

-Eaton-Lambert syndrome is caused by IgG mediated destruction of the presynaptic voltage-gated calcium channel at the presynaptic nerve terminal. -When the action potential depolarizes the nerve terminal, Ca+2 entry into the presynaptic neuron is limited, thereby reducing the amount of Ach that is released into the synaptic cleft -The postsynaptic nicotinic receptor is present in normal quantity and functions normally

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 -Higher plateau = greater efficacy -Lower plateau = lower efficacy -Once the plateau phase is reached, additional drug does NOT produce additional effect, it will only increase the risk of toxicity

How do you know if an atom carries a charge? -What is a charged atom called?

-Electrons = protons → neutral charge -Protons > electrons → positive charge -Electrons > protons → negative charge -An ion is an atom that carries a charge -Cations carry a positive charge -Anions carry a negative charge

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?

-Emergency decompression of the surgical site, if the surgeon isn't immediately available this falls on you - cricothyroidotomy may be required

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 coagulation studies are not easily obtained

Which neuraxial opioid can reactivate herpes simplex labialis?

-Epidural morphine -Usually presents 2-5 days after epidural morphine administration

What drugs counter the hypoglycemic effect of insulin?

-Epinephrine -Glucagon -Cortisol

How does adding epinephrine affect the duration of action of local anesthetics?

-Epinephrine extends local anesthetic duration -The alpha-1 agonist effect of EPI makes it a potent vasoconstrictor → decreased systemic uptake of drug

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

-Esmolol -Remifentanil -Aspirin -Clevidipine -Atracurium (and Hoffman elimination) -Etomidate (and hepatic)

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 ester, but it is metabolized by pseudocholinesterase and the liver

What is the relationship between etomidate and seizures?

-Etomidate causes myoclonus -In patients with seizure disorders, etomidate (or methohexital or alfentanil) may increase EEG activity and can be used to help determine the location of the seizure during cortical mapping

What are the causes of a radial nerve injury?

-External compression by an IV pole -Excessive cycling of the NIBP cuff -Upper extremity tourniquet -Sheets that are too tight if arms are tucked

How are inspiration and expiration affected with a fixed obstruction?

-Extrathoracic obstruction = normal during expiration, abnormal during inspiration -Intrathoracic obstruction = normal during inspiration, abnormal during expiration

What factors are in the extrinsic pathway, intrinsic pathway, and final common pathway?

-Extrinsic pathway → 3, 7 -Intrinsic pathway → 8, 9, 11, 12 -Final common pathway → 1, 2, 5, 10, 13

How does obesity affect FRC? -How about the other lung volumes and capacities?

-FRC is inversely proportional to BMI -The reduction in FRC (due to a decrease in ERV) below CC creates a situation where distal airway collapse occurs during tidal breathing -This leads to V/Q mismatch, stunt, and hypoxemia -GA causes FRC to fall by 50% (20% in non-obese) -A higher O2 consumption coupled with a smaller FRC predisposes this population to rapid desaturation during apnea

How does pregnancy affect the lung volumes and capacities?

-FRC is reduces as a function of a decrease in ERV and RV (ERV > RV) -An increased O2 consumption paired with a decreased FRC hastens the onset of hypoxemia

What is the function of each of the anterior pituitary hormones?

-FSH → Germ cell maturation and ovarian follicle growth -LH → Testosterone production (males) and ovulation (females) -ACTH → Adrenal hormone release -TSH → Thyroid hormone release -Prolactin → Lactation -Growth hormone → cell growth

What is the treatment for hemophilia A?

-Factor VIII concentrate -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

What factors impact Hofmann elimination?

-Faster → Alkalosis and hyperthermia -Slower → Acidosis and hypothermia

What are the diagnostic criteria for diabetes mellitus?

-Fasting plasma glucose > 126 mg/dL -Random glucose level > 200 mg/dL + classic symptoms -Two hour plasma glucose > 200 mg/dL during OGTT -Hemoglobin A1C > 6.5%

What is the mechanism of action of fenoldapam? -Why is it used?

-Fenoldopam is a selective DA1 receptor agonist that increases renal blood flow -Low dose fenoldopam (0.1-0.2 mcg/kg/min) is a renal vasodilator and increases RBF, GFR, and facilities Na+ excretion without affecting arterial blood pressure → may offer renal protection during CPB

What is the treatment for a "tet spell" that occurs during the perioperative period?

-FiO2 100% -Intravascular volume expansion -Increase SVR with phenylephrine -Reduce SNS (deepen anesthesia, beta-blockade) -Avoid inotropes (worsened RVOT obstruction) -Avoid excessive airway pressure *An infant may be placed in knee-chest position to mimic squatting

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

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

-Filtration occur at the glomerular capillary bed -Reabsorbtion and secretion occur at the peritubular capillary bed

Describe the pathophysiology of Alzheimer's disease.

-Findings include development of diffuse beta amyloid rich plaques and neurofibrillary tangles in the brain -Dysfunctional synaptic transmission & apoptosis

Describe the circulatory changes that occur during the transition to extrauterine life.

-First breath → lung expansion → decreased PVR -Placenta separates from uterine wall → increased SVR -PVR and SVR switch → LA pressure > RA pressure → the flap of the foramen ovale closes -Decreased PVR → reversal of blood flow through the ductus arteriosus → closure of DA -Decresed circulating PGE1 → closure of DA

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 *Most drugs follow this model

How does anterior spinal artery syndrome present?

-Flaccid paralysis of the lower extremities -Bowel and bladder dysfunction -Loss of temperature and pain sensation -Preserved touch and proprioception

Discuss the anesthetic considerations for maternal cocaine abuse.

-Flooding the synaptic cleft with NE increases the SNS tone -CV risks → tachycardia, dysrhythmias, myocardial ischemia -Acute intoxication increases MAC/Chronic use decreases MAC -OB risks → spontaneous abortion, premature labor, placental abruption, low APGAR scores -HTN is best treated with vasodilators, beta blockers can use HF is the SVR is significantly elevated -Hypotension may not respond to ephedrine in chronic cocaine users -Chronic cocaine abuse is associated with thrombocytopenia

Regarding hepatic clearance, what is flow-limited elimination?

-Flow-Limited Elimination (ER > 0.7) -High hepatic extraction ratio, clearance is dependent on liver blood flow -Increased liver blood flow → Increased clearance -Decreased liver blood flow → Decreased clearance

Detail the anesthetic management for the patient with preeclampsia.

-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 rule out thrombocytopenia (< 100,000) before performing a neuraxial block -Due to airway swelling, these patients have a higher incidence of difficult intubation -These patients have an exaggerated response to sympathomimetics and methergine -If they are receiving magnesium therapy, they will exhibit an increased sensitivity to neuromuscular blockers -Magnesium relaxes the uterus and increases the risk of postpartum hemorrhage

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

-Flumazenil is a competitive antagonist of the GABA-A receptor -Very high affinity, but short duration of action (30-60 minutes) -Repeat dosing may be necessary to prevent re-sedation -Initial dose → 0.2 mg IV, then titrated in 0.1 mg increments q1min

In what circumstances can thiopental be used for neuroprotection?

-Focal ischemia: Yes (CEA, temporary occlusion of cerebral arteries) -Global ischemia: No (Cardiac arrest)

What conditions increase FA/FI? -Which conditions decrease it?

-For FA/FI to increase → greater wash in and/or reduced uptake -For FA/FI to decrease → reduced wash in and/or increased uptake

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/100g/min -Maximal vasodilation occurs at a PaCO2 of 80-100 mmHg -Maximal vasoconstriction occurs at a PaCO2 of 25 mmHg

Where are platelets formed? -Where are they metabolized?

-Formed by megakaryocytes in the bone marrow -Cleared by macrophages in the reticuloendothelial system and the spleen

List 4 tests of tubular function and give the normal values for each.

-Fractional excretion of Na+ → 1-3% -Urine osmolality → 65-1400 mOsm/L -Urine sodium concentration → 130-260 mEq/day -Urine specific gravity → 1.003 - 1.030

List the name and function of the 4 lobes of the cerebral cortex

-Frontal - Contains the motor cortex -Parietal - Contains the somatic sensory cortex -Occipital - Contains the vision cortex -Temporal - Contains the auditory cortex and speech center *Wernicke's area - understanding speech *Broca's area - motor control of speech

What are the 3 ingredients required to produce a fire? -Give examples of each.

-Fuel -Oxidizer -Ignition source

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

-Full agonist: Binds to a receptor and turns on a specific cellular response -Partial agonist: Binds to a receptor, but is only capable of partially turning on a cellular response. 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. By definition, it does not have efficacy -Inverse agonist: Binds to the receptor and causes an opposite effect to that of a full agonist. It has negative efficacy.

What is the functional unit of the liver? -Describe its anatomy.

-Functional unit → lobule

What is the mechanism of action of opioids?

-G-protein coupled receptor: The agonism of the receptor instructs the G-protein to "turn off" adenylate cyclase. This reduces intracellular concentration of cAMP (second messenger) which reduces neuronal function

What is the mechanism of action for thiopental?

-GABA-A agonist → Depresses the reticular activating system in the brainstem -Low/normal dose: Increases the affinity of GABA for its binding site -High dose: Directly stimulates the GABA-A receptor

List 4 herbal supplements that increase bleeding risk.

-Garlic -Ginger -Gingko biloba -Saw palmetto

What are the 5 most important GI hormones? -What is the key function of each?

-Gastrin → When food enters the stomach, gastrin increase stomach acid and stimulates chief cells to secrete pepsinogen. In the presence of stomach acid, pepsinogen is converted to pepsin -Secretin → Tells the pancreas to secrete bicarbonate and the liver to secrete bile -Cholecystokinin → Tells the pancreas to release digestive enzymes and the gallbladder to contract -Gastric inhibitory peptide → Slows gastric emptying and stimulates pancreatic insulin release -Somatostatin → The universal "off" switch for digestion

List several examples of how Gay-Lussac's law can be applied in the operating room.

-Gay-Lussac's law (P / T) -Oxygen tank explodes in a heated environment

Detail the anesthetic management of the patient with autonomic hyperreflexia.

-General or spinal are the best options -An epidural may be used for a laboring mother, but is not as good as a spinal -HTN is treated with removal of the stimulus, deepening the anesthetic, and a rapidly acting vasodilator such as sodium nitroprusside -Bradycardia can be treated with atropine or glycopyrrolate -Administration of a positive chronotrope will worsen HTN -Adding lidocaine jelly to the cystoscope does not prevent AH

What is the risk of perioperative myocardial infarction in the patient with a previous MI?

-General population = 0.3% -MI within > 6 months = 6% -MI within 3-6 months = 15% -MI within < 3 months = 30% -Highest risk of reinfarction is greatest within 30 days of an acute MI. ACC/AHA guidelines recommend a minimum of 4-6 weeks before considering elective surgery

A patient presents for removal of a gloms tumor. What are your primary concerns when planning your anesthetic?

-Glomangiomas originate from neural crest cells. -They can release several vasoactive substances -Octreotide can be used to treat carcinoid-like s/sx (flushing, diarrhea, tachycardia) -Cranial nerve dysfunction can cause swallowing impairment → risk of aspiration and airway obstruction

What are the 3 determinants of glomerular hydrostatic pressure?

-Glomarular hydrostatic pressure is the most important determinant of GFR -Three determinants of glomerular hydrostatic pressure 1. Arterial BP 2. Afferent arteriole resistance 3. Efferent arteriole resistance

Name 3 airway blocks and identify the key landmarks for each one

-Glossopharyngeal nerve block: Palatoglossal arch at the anterior tonsillar pillar -Superior laryngeal nerve block: Greater cornu of hyoid -Transtracheal nerve block: Cricothyroid membrane

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

What factors stimulate glucagon release?

-Glucagon is secreted by pancreatic alpha cells

What drugs can be used to relax the sphincter of Oddi?

-Glucagon → increases risk of PONV -Naloxone → poor choice in surgical patient -Nitroglycerine

How does dextrose affect the tonicity of IV fluids?

-Glucose contributes to osmotically active molecules in the plasma -Glucose in D5W is metabolized to carbon dioxide and water → essentially these fluids are hypotonic -D5W = hypotonic -D5NS, D50.45%NS, D5LR = hypertonic

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

Describe the goals and strategies for mechanical ventilation in the patient with COPD.

-Goal is to prevent barotrauma and reduce air trapping. -Low tidal volume (6-8 mL/kg IBW) -Increased expiratory time to minimize air trapping -Slow inspiratory flow rate -Low levels of PEEP

When is the best time to use an Eschmann introducer?

-Grade 3 > Grade 2

What is somatostatin?

-Growth hormone-inhibiting hormone, regulates endocrine hormone output from the islet cells -Released by delta cells -Inhibits insulin AND glucagon -Inhibits splanchnic blood flow, gastric motility, and gall bladder contraction

Describe the pathophysiology of Gullain-Barre syndrome.

-Guillain-Barre Syndrome is characterized by an immunologic assault on myelin in the peripheral nerves. The action potential can't be conducted, so the motor endplate never receives the incoming signal -It usually persists for 2 weeks and ends with full recovery in 4 weeks

List the signs and symptoms of intracranial hypertension.

-H/A -N/V -Papilledema -Focal neurologic deficit -Decreased LOC -Seizures -Coma

What is HELLP syndrome? -What is the definitive treatment?

-HELLP → Hemolysis, Elevated liver enzymes, low platelets -HELLP develops in 5-10% of preeclamptic mothers. These patients experience epigastric pain and upper abdominal tenderness -Definitive treatment for HELLP syndrome (and preeclampsia) is delivery of the fetus

Compare and contrast type I and type II heparin induced thrombocytopenia.

-HIT occurs when the body mounts an immune response against heparin after it binds to platelet factor 4. IgG antibodies activate platelets, which ultimately results in uncontrolled clot formation.

How do HR, SV, and CO change in the elderly?

-HR, SV, and CO decrease

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 are the OSHA recommendations regarding inhalation anesthetic exposure for health care workers in the OR?

-Halogenated agents alone < 2 ppm -Nitrous oxide alone < 25 ppm -Halogenated agents and nitrous oxide < 0.5 ppm and 25 ppm

What things impair HPV? -What is the consequence of this?

-Halogenated anesthetics > 1 = 1.5 MAC -Phosphodiesterase inhibitors -Dobutamine -Vasodilators -IV anesthetics DO NOT inhibit HPV* -Anything that inhibits HPV will increase shunt

What is the definitive test for susceptibility to malignant hyperthermia?

-Halothane contracture test -Risk of false-negative result

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

How should you induce anesthesia in a patient undergoing a type C TEF repair?

-Head up position and frequent suctioning to minimize the risk of gastric aspiration -Awake intubation or inhalation induction with spontaneous ventilation -PPV → gastric distention → decreased thoracic compliance → downward spiral -Placement of g-tube allows for gastric decompression, open it to atmosphere before induction if patient already has one -Place the ETT below the fistula, but above the carina

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

What is the primary determinant of blood pressure in the neonate?

-Heart rate is the primary determinant of cardiac output and systolic BP -The neonatal myocardium lacks the contractile elements to significantly adjust contractility or stoke volume; the ventricle is noncompliant. Furthermore, the Frank-Starling relationship is underdeveloped in the newborn -The HR must be maintained to ensure adequate tissue perfusion and O2 delivery

Describe the Cormack and Leanne score.

-Helps us measure the view we obtain during direct vision laryngoscopy.

Discuss the pathophysiology of acute intermittent porphyria.

-Heme is a key component of hemoglobin, myoglobin, and the cytochrome P450 enzymes -Porphyria is caused by a defect in heme synthesis that promotes the accumulation of heme precursors (ALA induction) -Can be classified as acute or cutaneous → Acute intermittent porphyria is the most common and dangerous type

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

What are the doses for heparin (for CPB) and protamine?

-Heparin dose = 300-400 units/kg -Protamine dose = 1 mg for every 100 units of heparin

What is the mechanism of action of heparin?

-Heparin inhibits the intrinsic and final common pathways -Antithrombin III is a naturally occurring anticoagulant that circulates in the plasma. Heparin binds to antithrombin (AT) and accelerates its anticoagulant ability 1000x. -The heparin-AT complex neutralizes thrombin and activated factors X, XII, XI, and IX.

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

-Name 4 areas where brain herniation can occur.

-Herniation of the cingulate gyrus under the falx -Herniation of the contents over the tentorium cerebelli -Herniation of the cerebellar tonsils through the foramen magnum -Herniation of contents through a site of surgery or trauma

What is the P50 of fetal hemoglobin? -Why is this important?

-HgbF has a P50 of 19 mmHg, this shifts the curve to the left, creating an O2 partial pressure that facilitates passage of O2 from the mother to the fetus

What factors increase compound A production with sevoflurane?

-High concentrations over a long period of time -Low FGF -High temperature of CO2 absorbent -Increased CO2 production

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

-High risk procedures are "dirty" procedures 1. Dental procedures involving gingival manipulation and/or damage to mucosa lining 2. Respiratory procedures that perforate the mucosal lining with incision or biopsy 3. Biopsy of infective lesions on the skin or muscle

List 6 risk factors for perioperative cardiac morbidity and mortality for non-cardiac surgery.

-High risk surgery -History of ischemic heart disease (Unstable angina confers the greatest risk of perioperative MI) -History of CHF -History of CVD -Diabetes mellitus -Serum creatinine > 2 mg/dL

Which populations tend to have a greater percentage of TBW by weight? -Which have less?

-Higher TBW by weight = neonates -Lower TBW by weight = Females, obese, elderly

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

-Higher blood solubility -We can offset the effects of a higher blood solubility by increasing the inspired concentration on the vaporizer

Discuss the presentation, risks, and treatment of hypoglycemia in the perioperative period.

-Highest risk if insulin given during fasting -S/Sx: SNS stimulation -Difficult to diagnose under GA (even harder is patient is on a beta-blocker) -Possible cause of delayed emergence -Rebound hyperglycemia (Somogyi effect) may cloud diagnosis

What are the immunologic effects of opioids?

-Histamine release -Inhibition of cellular and humoral immune function -Suppression of natural Killer T cell function

What drugs should be avoided in the patient with carcinoid syndrome?

-Histamine releasing drugs -Succinylcholine induced fasciculations can cause hormone release from the tumor -Exogenous catecholamines can potentiate hormone release -Sympathomimetic agents: ephedrine and ketamine

What drug can be used to improve local anesthetic diffusion through tissue?

-Hyaluronidase can improve local anesthetic diffusion through tissue -Commonly used in ophthalmic blocks

Rank the opioids from most lipophilic to most hydrophilic. -How does lipophilicity affect rostral spread in the subarachnoid space?

-Hydrophilic drugs tend to remain in the subarachnoid space and travel towards the brain (rostral spread) -Lipophilic drugs tend to diffuse out of the subarachnoid space and enter the systemic circulation

What conditions increase the risk of CNS toxicity from LAST?

-Hypercarbia: Increases cerebral blood flow and increases drug delivery to the brain. Also decreases protein binding and increases the free fraction available to the brain -Hyperkalemia: Raises RMP, making neurons more likely to depolarize -Metabolic acidosis: Decreases the convulsion threshold and favors ion trapping inside the brain

What are glucocorticoid effects?

-Hyperglycemia -Weight gain -Increased risk of infection -Osteoporosis -Muscle weakness -Mood disorder

How does chronic kidney disease affect the serum potassium concentration? -How is hyperkalemia treated in this patient population?

-Hyperkalemia is the result of impaired potassium excretion → dialysis is indicated when serum K+ exceeds 6 mEq/L Other treatments -Glucose (25-50g) + insulin (10-20 units) -Hyperventilation → for every 10 mmHg decrease in PaCO2, the serum potassium level is reduced by 0.5 mEq/L -Sodium bicarbonate (50-100 mEq) -Calcium chloride does not change serum K+ concentration, it raises the TP in the myocardium an reduces the risk of lethal dysrhythmias

Why is calcium used to treat hyperkalemic cardiac arrest caused by succinylcholine?

-Hyperkalemia raises RMP -Administration of IV Ca+2 increase the threshold potential, which helps re-establish the normal difference between transmembrane potentials.

What are mineralocorticoid effects?

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

When is it ok for a patient with hyperthyroidism to undergo surgery? -What about a hypothyroid patient?

-Hyperthyroidism → DO NOT proceed to elective surgery until patient is euthyroid. Emergency surgery → beta blockers, potassium iodide, glucocorticoid, PTU -Hypothyroidism → Ok to proceed with mild to moderate disease

How are TSH, T3, and T4 levels affected by hyper and hypothyroidism?

-Hyperthyroidism → Low TSH + High T3 & T4 -Hypothyroidism → High TSH + Low T3 & T4

How and when does pyloric stenosis present?

-Hypertrophy of the pyloric muscle creates a mechanical obstruction at the gastric outlet (between the stomach and duodenum) -An 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

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

-Hyperventilation (PaCO2 30-35 mmHg) constricts the cerebral vessels → decreased CBF and ICP -Lowering the PaCO2 < 30 mmhm increases the risk of cerebral ischemia due to vasoconstriction and shifting the oxyhemoglobin dissociation curve to the left

What are the unique anesthetic considerations for the patient with DiGeorge syndrome?

-Hypocalcemia is common -If the thymus is absent, the child is at high risk for infection Treatment -Thymus transplant of mature T cell infusion *Use leukocyte-depleted irradiated blood

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

-Hypoperfusion → no intrinsic damage...yet Treatment -The risk is reduced by maintaining MAP > 65 mmHg and providing appropriate hydration -Restoration of RBF with IVF, hemodynamic support, and/or PRBCs -Renal prostaglandins mediate vasodilation in the kidney. NSAIDs reduce prostaglandin synthesis → avoid them if injury is a concern -An improvement in UOP following an intravenous fluid bolus confirms the diagnosis of prerenal azotemia

What is the most common complication of dialysis.

-Hypotension due to intravascular volume deletion and osmotic shifts

Describe the management for the patient with DIC.

-Hypovolemia → Treat with IV fluids -Coagulopathy → Replace consumed blood components with FFP, platelets, and cryoprecipitate -Severe microvascular thrombosis → IV heparin or LMWH

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

-Hypoxemai and cyanosis -Classically the child presents with a history of squatting during activity → this increases SVR and reduces the right-to-left shunt -Stress increases myocardial contractility and can cause a spasm of the infravalvular region of the RVOT -"tet spells" occur during stressful circumstances → exercise, crying, defamation, IV placement, during induction

What are the signs and symptoms of methemoglobinemia?

-Hypoxia -Cyanosis -Chocolate-colored blood -Tachycardia -Tachypnea -Mental status change -Coma or death *Cyanosis in the presence of a normal PaO2 is highly suggestive of methemoglobinemia

When is ICP measurement indicated? -What is the gold standard for measurement?

-ICP measurement is indicated with a GCS of < 7 -An intraventricular catheter is the gold standard for ICP measurement, but it can also be measured with a subdural bolt

What are the causes of median nerve injury?

-IV placed in the antecutibal space -Carpel tunnel syndrome -Elbow hyperextension -Forced elbow extension during positioning after neuromuscular blocker has been administered

What are the IV and PO doses for midazolam? -Why are they different?

-IV sedation: 0.01 - 0.1 mg/kg -IV Induction: 0.1 - 0.4 mg/kg -PO sedation: 0.5 - 1 mg/kg -PO bioavailability → 50% due to first-pass metabolism

What are the potential routes of administration for ketamine? -Include the dosages for each.

-IV: Induction → 1-2 mg/kg, Analgesia → 0.1-0.5 mg/kg -IM: 4-8 mg/kg -PO: 10 mg/kg

Discuss the modifications to the ACLS treatment protocol when applied to LAST.

-If EPI is used, the dose should be < 1 mg/kg -Amiodarone is the agent of choice for ventricular arrhythmias -Avoid vasopressin, lidocaine, and procainamide

How do you interpret the fraction excretion of sodium?

-If Fe(Na+) is < 1% then more sodium is conserved relative to the amount of creatinine cleared → prerenal azotemia If Fe(Na+) is > 3% then more sodium is excreted relative to the amount of creatinine cleared → impaired tubular function

What are the implications when a drug's Vd exceeds TBW? -What if Vd is less than TBW?

-If Vd > TBW, the drug is assumed to be lipophilic -It distributes into TBW + fat -It will require a higher dose to achieve a given plasma concentration -Ex: propofol, fentanyl -If Vd < TBW, the drug is assumed to be hydrophilic -It distributes into some or all of the body water, but not fat -It will require a lower dose to achieve a given plasma concentration -Ex: NMB's, albumin

Discuss the use of cephalosporins in the PCN allergic patient.

-If a patient reports an allergy to PCN, the he/she may receive a cephalosporin if the reaction A. Was not IgE mediated (anaphylaxis, bronchospasm, urticaria) B. Did not produce exfoliative dermatitis (Stevens-Johnson syndrome)

Describe the anesthetic concerns for a patient with omphalocele or gastroschisis.

-If gastroschisis, abdominal contents are placed in a bag after delivery, this minimizes water and heat loss -Monitor peak airway pressure, if PIP > 25-30 cmH20 the surgical closure may require staging -Measure SpO2 on the lower extremity to monitor for impaired venous return -Major fluid/electrolyte shifts

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

-If the BP cuff location is above the heart → BP reading will be falsely decreased -If the BP cuff location is below the heart → BP reading will be falsely increased -Arterial line: for every 10 cm change, the BP changes by 7.5 mmHg

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

Explain Bernoulli's principle and discuss it in the context of a river.

-If the fluid's velocity is high, then the pressure exerted on the walls of the tube will be low -If the fluid's velocity is low, then the pressure exerted on the walls of the tube will be high

What are your options if you lose the airway during induction in the patient with an anterior mediastinal mass?

-If the mass compresses the tracheobronchial tree before the airway is secured, it may be impossible to advance the ETT beyond the tumor. -Should airway collapse occur, repositioning the patient laterally or prone may restore potency to the airway -Emergent femoral-femoral CPB may be required if ventilation becomes impossible

What is the relationship between etomidate and seizure activity?

-If the patient does not have a history of seizures, then etomidate does not increase the risk of seizures -If the patient has a history of seizures, then etomidate can increase seizure-like activity

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 pressure -When the renal artery pressure is too low, the myogenic mechanism dilates the afferent arteriole to increase blood going to the nephron

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?

-If you are unable to replace the CO2 absorbent, increase the FGF to convert the circle system into a a semi-open system -Dont increase the minute ventilation

What are calcineurin inhibitors and how do they affect renal function?

-Immunosuppressant agents used to prevent rejection of transplanted organs -Side effects → HTN and renal vasoconstriction -Sirolumus carries a much lower risk of nephrotoxicity

Describe the presentation of ulnar nerve injury.

-Impaired sensation of 4th and 5th digits -Inability to abduct or oppose pinky finger -Chronic injury presents with claw hand (muscular atrophy)

Discuss the 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 sympathetic pathways from hypothalamus to blood vessels → inability to vasoconstrict or shiver → hypothermia *Hypothermia is the result of the inability of the cutaneous vasculature to vasoconstrictor, causing a redistribution of blood flow towards the periphery and allowing more heat to escape from the body

How does myasthenia gravis affect the pregnant mother and fetus?

-In 1/3 of women pregnancy intensifies the symptoms of myasthenia gravis -15-20% of infants have weakness and may require airway management

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

-In children < 5 years, Sch may cause bradycardia or asystole -More likely after repeat administration, atropine (.02 mg/kg) will mitigate this response

Discuss the pathophysiology of respiratory distress syndrome.

-In the absence of adequate surfactant, the alveoli remain stiff and non-compliant -Small alveoli tend to collapse -Larger alveoli become over distended -This promotes atelectasis, reduces the surface area where gas exchange can take place → V/Q mismatch -Hypoxemia leads to acidosis and the possibly the return to fetal circulation

How do you block the median nerve at the forearm?

-In the antecubital fossa, 3-5 mL of LA is injected medial to the brachial artery -Avoid this block in patients with carpal tunnel syndrome

In which region of the esophagus should an esophageal temperature probe be placed? -How does misplacement affect the reading?

-In the distal 1/3 to 1/4 of the esophagus -Increased if placed in the stomach -Decreased if placed in the proximal esophagus

Where is Ach released in the SNS?

-In the postganglionic region of sweat glands, piloerector muscles, and some vessels

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

-In the setting of an acute hemorrhage, there may not be time for a full crossmatch) -2nd best: Type-specific partially crossmatched blood -3rd best: Type-specific uncrossmatched blood -4th best: Type O negative uncrossmatched blood

Where does bilirubin come from? -How is it cleared from the body?

-In the spleen → Hgb → heme → unconjugated bilirubin -Unconjugated bilirubin is lipophilic → it's transported to the liver bound to albumin -The liver conjugates bilirubin with glucuronic acid, this increases it's water solubility -Conjugated bilirubin is excreted into the bile, metabolized by intestinal bacteria, and eliminated from the stool

How do halogenated anesthetics produce immobility?

-In the ventral horn of the spinal cord

Discuss bladder perforation that can occur during TURP.

-Inadvertent stimulation of the obturator nerve through the bladder wall can cause lower extremity movement, which may cause the resectoscope to puncture the bladder wall -Presentation → Abdominal and/or shoulder pain -A reduction of irrigation fluid is an early sign of bladder rupture -Patient will require emergent suprapubic cystotomy or possible Ex lap

What are the CNS effects of ketamine?

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

What are the cardiovascular effects of ketamine?

-Increased SNS tone (harmful with CAD) -Increased CO -Increased HR -Increased SVR -Increased PVR -Subhypnotic doses (< 0.5 mg/kg) usually don't activate the SNS -Ketamine is actually a myocardial depressant, the cardiovascular effects discussed above require an intact SNS. The myocardial depressant effects will be unmasked in patients with depleted catecholamine stores (sepsis) or sympathectomy

What factors affect volume of distribution in the obese population?

-Increased blood volume -Increased CO -Altered plasma protein binding -Lipid solubility of the drug → large fat mass greatly increased Vd of lipophilic drugs -Vd lipophilic drugs >> Vd for hydrophilic drugs → but both increase

What electrolyte disturbances can potentiate the effects of neuromuscular blockers?

-Increased concentration of lithium or magnesium -Decreased concentration of calcium and potassium

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

Describe the consequences of the capillary leak that occurs after a burn.

-Increased vascular permeability → edema -Loss of protein-rich fluid to the interstitial space → edema -Loss of intravascular volume → hypovolemia, hemoconcentation, and shock -Fluid shifts and edema are greatest in the first 12 hours following a burn -Colloids should be avoided the first 24 hours

How is tobacco smoke harmful?

-Increases SNS tone, sputum production, carboxyhemoglobin concentration, and risk of infection

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 do brain waves change during general anesthesia?

-Induction of general anesthesia → increased beta wave activity -Light anesthesia → increased beta wave activity -Theta and delta waves predominate during general anesthesia -Deep anesthesia produces burst suppression -Complete suppression or isoelectricity → 1.5-2 MAC

Discuss MAC in children. Does this rule apply to all volatile anesthetics?

-Infant → 2-3 months → MAC peaks at its highest level -Neonate → 0-30 days → MAC is lower than the infant -Premature → MAC is lower than the neonate

What is the most common congenital cardiac anomaly in infants and children? -How about adults?

-Infants and children = VSD -Adults = Bicuspid aortic valve

What should you keep in mind about infants and small children receiving succinylcholine? -What site produced the fastest onset (excluding IV)?

-Infants and small children should receive atropine 0.02 mg/kg (20 mcg/kg) with succinylcholine -If no IV access, submittal administration will produce the fastest onset

What is pancreatic polypeptide?

-Inhibits pancreatic exocrine hormone secretion, gallbladder contraction, gastric acid secretion, and gastric motility.

What is the mechanism of action of warfarin?

-Inhibits the enzyme vitamin K epoxide reductase complex, which is responsible for converting inactive vitamin K to active vitamin K. -Indirectly blocks the manufacturing of the vitamin K dependent factors → II, VII, IX, X, and protein C and S

Describe the physiologic changes that accompany electroconvulsive therapy.

-Initial response → increased PNS during the tonic phase -Secondary response → Increased SNS activity during the clonic phase

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

-Injury to facial nerve - CN VII - This causes ipsilateral facial paralysis

In addition to a brachial plexus block, which nerve must also be anesthetized to foster the tolerance of an upper extremity tourniquet?

-Intercostalbrachial nerve block -It arises from T2 -A field block is required to block this nerve. With the arm abducted and externally rotated, begin at the deltoid prominence and move inferiorly. A total of 5 mL of local anesthetic is sufficient

What is the risk of intra-arterial injection of thiopental? -What is the treatment?

-Intra-arterial injection → intense vasoconstriction + crystal formation → tissue necrosis -Treatment: Injection of vasodilator (phentolamine or phenoxybenzamine) or sympathectomy (stellate ganglion block, brachial plexus block)

What are the determinants of intraocular pressure? -What is the normal value?

-Intraocular perfusion pressure = MAP - IOP -Normal IOP = 10-20 mmHg -Aqueous humor is produced by the posterior chamber and reabsorbed by the anterior chamber

When is platelet transfusion indicated in the neonate? -What is the dose?

-Invasive procedures to maintain platelet count above 50,000 -Dose if obtained form aphaeresis = 5 mL/kg -Dose if pooled platelet concentrate = 1 pack/10 kg

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: The process where a molecule gains a positive or negative charge -Dependent upon: 1. The pH of the solution 2. The pKA of the drug

What is the most common cause of perioperative acute kidney injury? -Who is at the highest risk?

-Ischemia-reperfusion injury Highest risk -Pre-existing kidney disease -Prolonged renal hypoperfusion -Congestive heart failure -Advanced age -Sepsis -Jaundice -High risk surgery (aortic cross clamp and liver transplant)

What is the relationship between isoflurane and coronary steal?

-Iso is the most potent coronary artery dilator -Atherosclerotic vessels can't dilate, but normal vessels can → diversion of blood away from areas of higher resistance -No literature to support this

Which anesthetic technique can be used to maintain hepatic blood flow?

-Iso preserves hepatic blood flow best -Avoid PEEP → increased resistance to hepatic drainage -Ensure normocapnia -Liberal use of IV fluids -Regional anesthesia is ok as long as there are no coagulation defects

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 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

List 2 herbal supplements that reduce MAC.

-Kava kava -Valerian

How can you reduce atelectasis in the morbidly obese patient who is mechanically ventilated?

-Keep FiO2 < 80% during anesthetic maintenance to prevent absorption atelectasis To recruit collapsed alveoli → -Re-open collapsed alveoli with a recruitment maneuver (Valsalva). Give a breath to 40 cmH2O and hold for 10 seconds. This may temporarily reduce venous return, blood pressure, and heart rate -Hold open the re-expanded alveoli with PEEP or CPAP 5-10 cmH2O. This improves FRC, V/Q matching, and arterial oxygenation

What is the best IV induction agent for the patient with tetralogy of Fallot?

-Ketamine is the best induction agent, it increases SVR and reduces shunting

How does obesity impact the cardiovascular system?

-Key changes: Expansion of intravascular blood volume and high cardiac output state -Increased CO is mainly a result of increased SV - HR is usually normal -Venous return increases → leading to a dilated heart, which eventually becomes thicker to compensate for increased wall stress → diastolic dysfunction

How does Duchenne muscular dystrophy affect pulmonary function?

-Kyphoscoliosis → decreased pulmonary reserve → increased secretions -Respiratory muscle weakness

Discuss the use of a thoracic paravertebral block.

-LA is injected into the paravertebral space and targets the ventral rams of the spinal nerve as it exits the vertebral foramen -Think of it like a single shot, unilateral epidural -Provides analgesia for breast surgery, thoracotomy, and rib fracture

Discuss the role of ionization with respect to local anesthetics.

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

How do local anesthetics affect neuronal depolarization?

-LA's bind to the alpha-subunit on the inside of the Na+ channel. -When a critical number of sodium channels are blocked, there aren't enough open channels for sodium to enter → the cell can't depolarize and the AP can't be propagated

Contrast the maximum recommended peak inspiratory pressures for an LMA-Unique vs LMA-Proseal vs LMA-Supreme.

-LMA-Unique = < 20 cmH2O -LMA-ProSeal = < 30 cmH2O -LMA-Supreme = < 30 cmH2O

Which opioid has the largest volume of distribution? -Which has the smallest?

-Largest Vd = Fentanyl -Smalles Vd = Remifentanil

Which type of fetal decelerations cause concern?

-Late and variable decelerations require urgent assessment of fetal status

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

-Lateral femoral cutaneous n. -Femoral n. -Obturator n. -AKA lumbar plexus block

What is the active metabolite of atracurium and cisatracurium? -What is the clinical significance?

-Laudanosine -It is capable of producing seizures -Not a problem in the OR, but can be a problem with a prolonged infusion in the intensive care unit

What law can be used to describe ventricular afterload?

-Law of Laplace -Wall stress = (Intraventricular pressure x radius) / Ventricular thickness Wall stress is reduced by: -Decreased intraventricular pressure -Decreased radius -Increased wall thickness

Which law describes the relationship between aortic diameter and risk of aortic rupture in the patient with an abdominal aortic aneurysm? -When is surgical correction for an abdominal aortic aneurysm recommended?

-Law of Laplace → the diameter of the AAA correlates with the risk of rupture -Wall tension = Transmural pressure x Vessel radius -Increased diameter → Increased transmural pressure → Increased wall tension -Surgical correction is recommended when the aneurysm exceeds 5.5 cm

When is a nasopharyngeal airway contraindicated?

-LeFort II or III fracture -Basilar skull fracture -CSF rhinorrhea -Raccoon eyes -Periorbital edema -Coagulopathy -Previous transsphenoidal hypophysectomy or Caldwell-Luc procedure

List 6 complications of hypertension.

-Left ventricular hypertrophy -Ischemic heart disease -Congestive heart failure -Arterial aneurysm (aorta, cerebral circulation) -Stroke -End-stage renal disease

What are the S/Sx of gallstones?

-Leukocytosis -Fever -RUQ pain → worse with inspiration (Murphy's sign)

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

-Leukoreduction removes WBCs from RBCs and platelets -Removing the WBCs reduces the risk of HLA alloimunization, febrile non hemolytic transfusion reactions, and CMV transmission.

What is the treatment for acute intermittent porphyria?

-Liberal hydration -Glucose supplementation -Heme arginate -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 does "laser" stand for? -How is this different from ordinary light?

-Light Amplification by Stimulated Emission of Radiation -Laser light is monochromatic, coherent, and collimated

List 6 risk factors for difficult supraglottic device placement.

-Limited mouth opening -Upper airway obstruction -Altered pharyngeal anatomy -Poor airway compliance -Increased airway resistance -Lower airway obstruction

What is the role of the line isolation monitor? What should you do if it alarms?

-Line isolation monitor assesses the integrity of the ungrounded power system in the OR, it tells you how much current could potentially flow though you or a patient if a second fault occurs -Primary purpose of LIM → Alert OR staff of first fault -Does NOT protect you or the patient from shock -LIM will alarm when 2-5 mA of leak current is detected -Alarm sounds → unplug the last piece of equipment that was plugged in

What determines local anesthetic potency?

-Lipid solubility is the primary determinant of potency -The more lipid soluble an LA, the easier it can traverse the neuronal membrane -Intrinsic vasodilating effect is a secondary determinant of potency -Vasodilation increases uptake into systemic circulation → less LA available to anesthetize the nerve

What conditions reduce albumin concentration?

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

How can halogenated anesthetics cause hepatic injury? -Which agent presents the greatest risk?

-Liver metabolizes des, iso, and halothane into inorganic fluoride ions and TFA -Hepatitis is believed to be the result of an immune-mediated reaction caused by TFA. -Halothane presents the greatest risk >>> des > iso

How do you calculate the loading dose for an IV medication? -How about a PO medication?

-Loading dose = (Vd x Desired plasma concentration) / Bioavailability -For an IV drug, the bioavailability is always 1 -For a PO drug, the bioavailability will be less than 1. It may not be absorbed completely and/or it may be subjected to first pass metabolism

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

-Local anesthesia is the preferred technique for pericardiocentesis -If general anesthesia is required → preserve myocardial function

Describe the presentation of hypermagnesemia.

-Loss of deep tendon reflexes → 4-6.5 mEq/L or 10-12 mg/dL -Respiratory depression → 6.5-7.5 mEq/L or > 18 mg/dL -Cardiac arrest → > 10 mEq/L or > 25 mg/dL

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

-Loss of the a wave occurs when synchronized contraction of the right atrium is lost -Atrial fibrillation -V-pacing if the underlying rhythm is asystole

Compare and contrast low, intermediate, and high dose epinephrine.

-Low (0.01-0.03 mcg/kg/min): At low doses, non-selective beta effects predominate. Beta-1 stimulation increases HR and contractility while beta-2 stimulation mediates vasodilation on the skeletal muscle. The net effect is typically an increased CO with a reduction in SVR and possible a slight reduction in BP -Intermediate (0.03 - 0.15 mcg/kg/min): Dose range is characterized by mixed beta and alpha effects -High (> 0.15 mcg/kg/min): The alpha effects prevail and BP rises. Supra ventricular tachyarrythmias are common

Describe the EKG changes that can accompany obesity.

-Low voltage EKG → increased distance between heart and leads -Left-axis deviation → The stomach pushes the heart up and to the left. There is also LVH secondary to volume overload and HTN -Right axis deviation → RVH from OSA and volume overload -QT prolongation → Increases the risk of sudden death -Ischemia → Oxygen supply and demand mismatch -Dysrhythmias → Caused by fatty infiltration of the conduction system, myocardial hypertrophy, hypoxemia, hypercarbia, obesity hypoventilation syndrome, and ischemic heart disease

Name the 6 terminal branches of the lumbar plexus.

-Lumbar plexus arises from the anterior rami of L1-L4

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

A 3 kg term neonate requires emergency exploratory laparotomy for necrotizing enterocolitis. Her preoperative hematocrit is 50%. What is the maximum allowable blood loss to maintain a hematocrit of 40%?

-MABL = 80 mL x [(50-40)/50] = 48 mL

How is the anesthetic requirement altered in the alcoholic patient? -Why?

-MAC is decreased in the acutely intoxicated patient -MAC is increased in the chronic alcohol abuser that is not intoxicated -Alcohol potentiates GABA → increased effect of benzodiazepines -Alcohol inhibits NMDA receptors

How does obesity impact your selection if inhaled anesthetic agents?

-MAC is not changed by obesity -Agents with the lowest blood:gas coefficients should be used -Sevoflurane or desflurane provide a faster emergence than isoflurane or propofol -N2O is generally avoided because it restricts the FiO2 available

How do we quantify anesthetic potency? -What is this value for each inhalation agent?

-MAC is the measure of potency

What are MAC-bar and MAC-awake?

-MAC-bar → The alveolar concentration required to block the autonomic response following a supra maximal painful stimulus - 1.5 MAC -MAC-awake → The alveolar concentration at which a patient opens his or her eyes - 0.4-0.5 MAC during induction, as low as 0.15 MAC during recovery

What drugs extend or enhance the hypoglycemic effect of insulin?

-MAOIs -Salicylates -Tetracycline

What is the mechanism of action of the amylin agonists? List an example from this drug class.

-MOA: Decrease glucagon release from pancreatic alpha cells and reduce gastric emptying -Examples: Pramlintide Key Facts: -Risk of hypoglycemia if co-administered with insulin

What is the mechanism of action of the thiazolidinediones? List an example from this drug class.

-MOA: Decrease peripheral insulin resistance and increase hepatic glucose utilization -Examples: Rosiglitazone, Pioglitazone Key Facts: -Does NOT cause hypoglycemia -Black box warning d/t risk of CHF

What is the mechanism of action of the dipeptidyl-peptidase-4 inhibitors? List an example from this drug class.

-MOA: Increase insulin release from pancreatic beta cells and decrease glucagon release from alpha cells -Examples: suffix - liptin Key Facts: -Risk of hypoglycemia

What is the mechanism of action of the glucagon-like peptide-1 receptor agonists? List an example from this drug class.

-MOA: Increases insulin release from beta cells, decreases glucagon release from alpha cells, and prolongs gastric emptying -Examples: Eventide, Liraglutide Key Facts: -Risk of hypoglycemia

What is the mechanism of action of the biguanides? List an example from this drug class.

-MOA: Inhibit gluconeogenesis and glycogenolysis in the liver and decrease peripheral insulin resistance -Examples: Metformin Key Facts -Does not cause hypoglycemia -Risk of metabolic acidosis -Often used for polycystic ovarian disease

What is the mechanism of action of the alpha-glucosidase inhibitors? List an example from this drug class.

-MOA: Slows digestion and absorption of carbohydrates from the GI tract -Examples: Acarbose, Miglitol Key Facts: -Does NOT cause hypoglycemia

What is the mechanism of action of the sulfonylureas? List an example from this drug class.

-MOA: Stimulate insulin secretion from pancreatic beta cells -Examples: Glyburide, Glipizide, Glimepiride Key Facts -Risk of hypoglycemia -Avoid if sulfa allergy

What is the mechanism of action of the meglitinides? List an example from this drug class.

-MOA: Stimulate insulin secretion from pancreatic beta cells -Examples: Repaglinide, Nateglinide Key Facts: -Risk of hypoglycemia

What is the difference between macro and microshock?

-Macroshock → Comparatively larger amount of current that is applied to the external surface of the body. The impedance of the skin offers a high resistance, so it takes a larger current to induce V-fib -Microshock → Comparatively smaller amount of current that is applied directly to the myocardium. The high resistance of skin is bypassed, so it takes a significantly smaller amount of current to induce V-fib

What is the treatment for Torsades de points?

-Magnesium sulfate -Cardiac pacing to increase the heart rate will reduce the AP duration and the QT interval

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 > 100-150 mL/hr -Sodium bicarbonate or acetazolamide to alkalize the urine *Hemolysis from a hemolytic reaction is treated the same way

What conditions cause vitamin K deficiency?

-Malabsorptive diseases -Impaired GI flora -Decreased bile production

How does mannitol reduce ICP? -What problems can arise when mannitol is used this way?

-Mannitol (0.25-1 g/kg) increases serum osmolarity and pulls water across the BBB towards the bloodstream -If the BBB is disrupted, mannitol enters the brain and promotes cerebral edema -Mannitol transiently increases blood volume → stress on the heart

What prenatal finding suggests esophageal atresia? -How is the diagnosis confirmed after birth?

-Maternal polyhydramnios is a key diagnostic indicator for TEF → EA prevents the fetus from swallowing amniotic fluid -Diagnosis is confirmed by the inability to pass a gastric tube into the stomach -Other S/Sx → choking, coughing, and cyanosis during oral feeding

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

-Max dose of lidocaine for tumescent anesthesia is 55 mg/kg -4,950 mL of tumescent solution

Why is the burn patient at risk for abdominal compartment syndrome? -What is the diagnosis and treatment of this complication?

-May result from aggressive fluid resuscitation -Intra-abdominal HTN is defined as IAP > 20 mmH2O AND evidence of organ dysfunction -Treatment → neuromuscular blockade, sedation, diuresis, abdominal decompression via laparotomy

Describe the anesthetic management of the patient with pyloric stenosis.

-Medical (not surgical) emergency, surgery should be postponed until the fluid, electrolyte, and acid-base status are optimized -Anticipate a full stomach, empty the stomach before induction -Liberal hydration to correct dehydration -Postoperative apnea is common → CSF pH remains alkalotic even after serum acid-base status is normalized

How can you calculate ideal body weight for a man? -For a woman?

-Men (kg) → Height (cm) - 100 -Women (kg) → Height (cm) - 105

Which opioid is most likely to cause QT prolongation?

-Methadone → Torsades de pointes → very rare

What induction agent is the gold standard for ECT? -Why? -What is the induction dose?

-Methohexital is the gold standard for ECT therapy -It decreases the seizure threshold and produces a better quality seizure -Induction dose: 1 - 1.5 mg/kg

What is the treatment for methemoglobinemia? -How does this work?

-Methylene blue - 1-2 mg/kg over 5 minutes to a maximum of 7-8 mg/kg -Methylene blue is metabolized by methemoglobin reductase to form leucomethylene blue → reduces methemoglobin (Fe+3) back to hemoglobin (Fe+2)

Which opioid antagonist is least likely to reverse respiratory depression? -Why?

-Methylnaltrexone has a quaternary amino group that prohibits passage across the BBB -Helpful for peripheral effects, such as opioid induced bowel dysfunction

What drugs increase the risk of extrapyramidal S/Sx in the patient with Parkinson's disease?

-Metoclopramide -Butyrophenones (haloperidol & droperidol) -Phenothiazines (promethazine)

Which induction agents produce an active metabolite?

-Midazolam → 1-hydroxymidazolam (0.5 potency of parent compound) -Ketamine → norketamine (0.3-0.5 potency of parent compound) -Fospropofol produces propofol -Propofol, etomidate, dexmedetomidine → no active metabolites

What ligaments are penetrated during the midline approach to the epidural space? -How about the paramedian approach?

-Midline: Supraspinous ligament, interspinous ligament, ligamentum flavum -Paramedian approach: Ligamentum flavum *You should never pass through the anterior or posterior longitudinal ligaments

What concept is analogous to ED50 for local anesthetics?

-Mimimum effective concentration (Cm) → the concentration of local anesthetic that is required to block conduction -Fibers that are more easily blocked have a lower Cm -Fibers that are more resistant to blockade have a higher Cm

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 -Third-space loss is not included in the first hour of anesthesia

How can we apply the inverse square law to radiation exposure?

-Minimum safe distance from the radiation source is 6 feet -Inverse-square law

How does minute ventilation change in the elderly?

-Minute ventilation increases -Increased Vd necessitate an increased Ve to maintain a normal PaO2

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

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

Discuss diabetic ketoacidosis.

-More common with type I DM -Usually caused by infection -Not enough insulin → ketoacidosis, hyperosmolarity and dehydration -Patient is hyperglycemic (> 250 mg/dL), but cells are starved for fuel -Metabolic acidosis causes Kussmaul respirations -Acetone causes 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 glucoronide (inactive) and morphine-6-glucuronide (active) -Impaired renal function → decreased MP6 excretion → respiratory depression

Discuss the use of opioids in the patient with chronic kidney disease.

-Morphine is metabolized to morphine-6-glucuronide. This product is more potent than morphine and relies on renal excretion → respiratory depression -Meperidine is metabolized to normeperidine → convulsions -Fentanyl, sufentanil, alfentanil, and remifentanil do not produce active metabolites -Hydromorphone may or may not, but is safe in renal failure

What are the pros and cons of general anesthesia for cesarean section?

-Mortality is 17x higher with a general anesthetic -Most common cause of maternal death is failure to successfully manage the airway

Discuss the flammability of endotracheal tubes in the context of laser surgery on the airway.

-Most ETTs are flammable -Don't use laser reflective tape, use a laser reflective ETT -The cuff is the most vulnerable component of the ETT -Fill the cuff with saline (dye is optional) -Laser resistant ETTs do not reduce the risk of fire when electrosurgical cautery is used

What is the primary site of metabolism of the commonly used beta blockers? -What are 2 exceptions?

-Most beta-blockers depend on the liver as their primary site of metabolism. Exceptions -Esmolol is metabolized by RBC esterases -Atenolol is eliminated by the kidneys

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 radiation -Thyroidectomy

What are the first and second most common causes of chronic hepatitis?

-Most common = alcoholism -Second most common = hepatitis C

Describe the "needle through needle" technique for CSE.

-Most common approach -The epidural space is identified with the epidural needle. -A spinal needle is placed through the epidural needle and the LA and/or opioid is injected into the intrathecal space -The spinal needle is removed -An epidural catheter is threaded through the epidural needle

Discuss the absolute and relative contraindications to ECT.

-Most common cause of death is MI and dysrhythmias

What are the first and second most common causes of chronic kidney disease?

-Most common cause → DM -Second most common cause → HTN

Discuss Epstein's anomaly.

-Most common congenital defect of the tricuspid valve, usually an ASD or PFO -Characterized by a downward displacement of the tricuspid valve and atrialization of the right ventricle -Tricuspid regurgitation can be severe -Right-to-left shunting -SVT is common -RV failure is common in the postoperative period

When is the best time to use an airway exchange catheter and what can you do with it?

-Most common device used to manage extubation of a difficult airway -ETCO2 measurement -Jet ventilation -Oxygen insufflation

Which position is most likely to cause compartment syndrome?

-Most common in the lithotomy position -The lithotomy position is associated with increased leg compartment pressure and raising the legs above the heart reduces lower extremity perfusion pressure -Taken together, these changes set the stage for leg ischemia -This process can progress to rhabdomyolysis and/or reperfusion injury → treatment - fasciotomy

What surgical procedure presents the most significant risk of ION? -What are other procedure and patient risk factors?

-Most common procedure that places patients at risk of ION is spine surgery

What are the cardiovascular effects of dexmedetomidine?

-Most common side effects are bradycardia and hypotension -Rapid administration of dexmedetomidine can cause HTN (alpha-2 stimulation in the vasculature → vasoconstriction), this effect is usually short lived

What is the most common clinical finding in a patient with subarachnoid hemorrhage? -What are other S/Sx?

-Most common → Intense H/A that is often described as "the worst one of my life" -Loss of consciousness -N/V -Photophobia

What is the most common eye complication in the perioperative period? -What is the most common cause of vision loss?

-Most common: Corneal abrasion -Ischemic optic neuropathy is the most common cause of vision loss

What is the most common etiology of hyperthyroidism? -What are the other causes?

-Most common: Graves disease (autoimmune) -Myasthenia gravis -Multinodular goiter -Carcionma -Pregnancy -Pituitary adenoma -Amiodarone

Why do desflurane and isoflurane sometimes increase heart rate?

-Most likely due to SNS activation from respiratory irritation -Can be minimized with opioids, alpha-2 agonists, or beta-1 antagonists

What its the most sensitive indicator of MH? -What is the time course of the other S/Sx?

-Most sensitive indicator is an EtCO2 that rises out of proportion

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

Describe the pathophysiology of myasthenia gravis.

-Myasthenia gravis is an autoimmune disease. IgG antibodies destroy post-junctional nicotinic acetylcholine receptors at the NMJ. Although Ach is present in sufficient quantity, there aren't enough receptors to translate the extracellular signal into an intracellular response → skeletal muscle weakness -Key feature: Skeletal muscle weakness that becomes worse later in the day

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 cardiac output

What is the relationship between etomidate and myoclonus?

-Myoclonus: Involuntary skeletal muscle contractions, dystonia, or tremor -Likely due to an imbalance between excitatory and inhibitory pathways → NOT a seizure

How does rhabdomyolysis affect renal function?

-Myoglobin binds oxygen inside of the myocyte, when it is released into circulation it is freely filtered at the glomerulus -This results in tubular obstruction and acute tubular necrosis -In addition, myoglobin scavenges nitric oxyde, leading to renal vasoconstriction and ischemia.

What is the difference between myxedema coma and cretinism?

-Myxedema coma → occurs with end-stage hypothyroidism. Coma is a consequence of severely impaired thyroid function -Cretinism → 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 anesthesia would otherwise suggest

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

What is the relationship between N2O and anesthetic equipment?

-N2O will increase the volume and pressure in: -ETT cuff -LMA cuff -Balloon-tipped PA catheter *Always attach a manometer

What is the mechanism of action for ketamine?

-NMDA receptor antagonist (antagonizes glutamate) -Secondary receptor targets → opioid, MAO, serotonin, NE, muscarinic, Na+ channels -Ketamine dissociates the thalamus (sensory) from the limbic system (awareness)

Discuss the pathophysiology of amyotrophic lateral sclerosis.

ALS causes progressive degeneration of motor neurons in the corticospinal tract. Astrocytic gliosis replaces the affected motor neurons. Both the upper as well as the lower motor neurons are affected *Etiology is unknown

How does diabetes mellitus affect the autonomic nervous system?

ANS dysfunction: -Painless myocardial ischemia -Reduced vagal tone → tachycardia -Risk of dysrhythmias -Orthostatic hypotension -Imparied respiratory compensation to hypoxia and hypercarbia → increased sensitivity to anesthetic drugs -Delayed gastric emptying -Impaired thermoregulation -Regional anesthesia may worsen neurologic defects in the patient with diabetic polyneuropathy -Diarrhea and constipation

How do you treat a patient with ATIII deficiency?

AT III concentrate or FFP

Define dysesthesia and give an example.

Abnormal and unpleasant sense of touch -Ex: Burning sensation from diabetic neuropathy

List the absolute and relative contraindications to extracorporeal shock wave lithotripsy.

Absolute contraindications -Pregnancy -Risk of bleeding Relative contraindications -Pacemaker/ICD -Calcified aneurysm of the aorta or renal artery -UTI -Obstruction beyond the renal stone -Morbid obesity

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

Describe the presentation of adrenal insufficiency.

Adrenal insufficiency → too little mineralocorticoid, glucocorticoid, and androgen -Primary: Addison's disease → Adrenal glands don't secrete enough steroid hormones -Secondary: Decreased CRH or ACTH release Presentation -Muscle weakness/fatigue -Hypotension -Hypoglycemia -Hyponatremia -Hyperkalemia -Metabolic acidosis -Anorexia -N/V -Hyperpigmentation of the knees, elbows, knuckles, lips, and buccal mucosa

What is the main difference between vasopressin and aldosterone?

Aldosterone increases water and sodium reabsorption, vasopressin only increases water reabsorption.

What is the unitary hypothesis?

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

What is the mechanism of action for dexmedetomidine?

Alpha-2 agonist → decreased cAMP → Inhibits the locus coeruleus in the pons (sedation)

List 2 conditions commonly associated with Kussmaul's sign.

Although it can occur with any condition that limits RV filling, associate Kussmaul's sign with: -Constrictive pericarditis -Pericardial tamponade

What is the difference between minute ventilation and alveolar ventilation?

Alveolar ventilation removes the anatomic dead space gas from the minute ventilation equation

How does the aortic cross clamp contribute to the risk of anterior spinal artery syndrome?

An aortic cross clamp 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 → Beck's syndrome

What is pulsus paradoxus?

An exaggerated decrease in SBP during inspiration (more than 10 mmHg) → this finding suggests impaired diastolic filing

What is an ionic bond?

An iconic bond involves the complete transfer of valence electrons from one atom to another. This leaves one atom with a negative charge and the other with a positive charge -Common with metals, acids, and bases

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

Anatomic changes -Less space between the posterior spinous processes -Decreased intravertebral disc height -Narrow intervertebral foramen -Calcification of joints

Compare and contrast android and gynecoid obesity.

Android obesity (Apple shape) -More common in men -Characterized by central or abdominal visceral fat accumulation -Increased risk of ischemic heart disease, HTN, dyslipidemia, insulin resistance, and death Gynecoid obesity (Pear shaped) -More common in women -Characterized by gluteal and femoral fat accumulation -Gynecoid fat is metabolically inactive (better than central fat) -Increased risk of joint disease and varicose veins -This type of fat is associated with a reduced incidence of non-insulin dependent DM

What is the anion gap? -What does it tell you?

Anion gap = Major cations - major anions -Anion gap = [Na+] - ([Cl-] + [HCO3-]) -AG > 14 → Gap acidosis -AG < 14 → Non-gap acidosis

How does fluorination affect the physiochemical characteristics of halogenated anesthetics?

As a general rule, fluoride ions tend to: -Decrease potency -Increase vapor pressure -Increase resistance to biotransformation

How is blood pressure affected in the patient with coarctation of the aorta?

As a general rule: -SBP is elevated in the upper extremities -SBP is reduced in the lower extremities

How does the site of measurement affect the BP reading?

As the pulse moves from he aortic root towards the periphery, the systolic pressure increases, diastolic pressure decreases, and pulse pressure widens. -MAP remains constant through the arterial tree

What is Samter's triad? -Why is it important?

Aspirin exacerbated respiratory disease -Asthma -Allergic rhinitis -Nasal polyps *These patients can develop life threatening bronchospasm after aspirin administration

How does pregnancy affect uterine blood flow?

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

What is a polar covalent bond?

Atoms share electrons, but the electrons tend to remain closer to one atom than the other. This creates a polar molecule.

What is the most common dysrhythmia associated with mitral stenosis?

Atrial fibrillation due to the altered anatomy from increased LA pressure

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

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

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 & delta) > Large diameter A fibers (alpha & beta)

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

Backache and radicular pain

What is baricity and how does it influence you selection of local anesthetic?

Baricity describes the density of a local anesthetic solution relative to the CSF. -An isobaric solution describes a local anesthetic solution whose basicity is similar to CSF -A higher density solution is hyperbaric -A lesser density solution is hypobaric -A hyperbaric solution will sink, a hypobaric solution will rise, and an isobaric solution will remain in place -As a general rule, solutions in dextrose are hyperbaric, in saline are isobaric, and in water are hypobaric. Procaine 10% in water is an exception (it's hyperbaric; presumable because there are so may molecules in 10% solution)

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

Baroreceptor reflex

Why can't spirometry measure FRC?

Because the FRC contains the RV

How do patients with myasthenia gravis respond to neuromuscular blockers?

Because there is a reduction in the number of nicotinic M receptors at the NMJ, patients have an increased sensitivity to non-depolarizing NMB's and a resistance to Sch -Usually volatile agent provides enough relaxation for surgery

What are the 2 classes of non depolarizing neuromuscular blockers? -Which drugs belong in each?

Benzylisoquinolinum compounds -Atracurium -Cisatracurium -Mivacurium -Aminosteroid compounds -Rocuronium -Vecuronium -Pancuronium

Why are beta blockers used to treat hyperthyroidism?

Beta blockers reduce SNS stimulation and inhibit peripheral conversion of T4 to T3

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

Bilateral -Acute = Respiratory distress (unopposed action of cricothyroid muscles) -Chronic = No respiratory distress

How does the Trendelenburg position affect the distribution of blood volume, MAP, and venous pressure?

Blood shifts towards the central circulation -Increased venous return → increased position on Frank-Starling curve MAP stays the same or increases -Although venous return initially increases, this is followed with vasodilation and a slower HR Venous pressure increases -Hydrostatic pressure → edema of the face, eye, and airway -Intracranial HTN

Discuss the relationship between blood type, erythrocyte antigens, and plasma antibodies.

Blood type is determined by specific glycoproteins present on the erythrocyte membrane, these glycoproteins have an antigenic potential -If an antigen is expressed on the erythrocyte, there will NOT be an antibody against that specific antigen in the plasma -If an antigen is NOT expressed on the erythrocyte, then there will be an antibody against that specific antigen in the plasma

What is the boiling point and how is it affected by atmospheric pressure?

Boiling point is the temperature at which a liquid's vapor pressure equals atmospheric pressure -Increased atmospheric pressure → increased boiling point -Decreased atmospheric pressure → decreased boiling point

How do you dose the reversal agent for the patient with chronic kidney disease?

Both anticholinesterases and anticholinergics sued to reverse NMBs under go renal elimination → they require no dosage adjustments

Describe the anatomy of the cubital tunnel.

Boundaries of the cubital tunnel: -Medial epicondyle of the humerus -Olecranon process of the ulna -Cubital tunnel retinaculum -The ulnar nerve emerges from the cubital tunnel between the humeral and ulnar heads of the flexor carpi ulnaris

How does succinylcholine affect heart rate? -Why?

Bradycardia -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

Why are patients with myasthenia gravis prone to aspiration?

Bulbar muscle weakness (mouth and throat) manifests as difficulty handling oral secretions → increased risk of aspiration

How does neuraxial anesthesia affect the neuroendocrine response to stress?

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

How is lymph returned to the systemic circulation?

By way of the thoracic duct at the juncture of the internal jugular and subclavian vein -Greater risk of chylothorax during left sided IJ insertion

What is the mechanism of action for COX inhibitors? -Which agents provide irreversible COX inhibition?

COX inhibitors prevent platelet aggregation by blocking COX-1. This stops the conversion of arachidonic acid to prostaglandins and ultimately thromboxane A2. -Aspirin is irreversible - it lasts for the life of the platelet -NSAIDs are reversible - their duration is shorter than the life of the platelet

What is the treatment for hypermagnesemia?

Calcium chloride

Describe the mechanism of action, clinical use, and key side effects of carbonic anhydrase inhibitors.

Carbonic anhydrase inhibitors -Acetazolamide -Dorzolamide MOA -Noncompetitive inhibition of carbonic anhydrase in the proximal tubule → net loss of HCO3 and N+ with a net gain of H+ and Cl- Clinical uses -Open angle glaucoma -Altitude sickness -Central sleep apnea Key side effects -Metabolic acidosis -Hypokalemia

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

How does Duchenne muscular dystrophy affect cardiac function? -What EKG findings might you expect?

Cardiac considerations -Degeneration of cardiac muscle → reduced contractility, cardiomyopathy, CHF EKG changes -Impaired cardiac conduction → sinus tachycardia and short PR interval

What are the cardiovascular and respiratory effects of propofol?

Cardiovascular -Decreased BP -Decreased SVR -Decreased venous tone → decreased preload -Decreased myocardial contractility Respiratory effects -Shifts CO2 response curve down and to the right → respiratory depression and/or apnea -Inhibits hypoxic ventilatory drive

What are the cardiovascular and respiratory effects of etomidate?

Cardiovascular -Etomidate's key benefit is hemodynamic stability -SVR is decreased, which accounts for a small reduction in BP -It does not block the SNS response to laryngoscopy → opioids or esmolol will help Respiratory -Mild respiratory depression (less than propofol or barbiturates)

What are the cardiovascular and respiratory effects of thiopental?

Cardiovascular -Hypotension is the result of venodilation and decreased preload; myocardial depression is a secondary cause -Non-immunogenic histamine release -Baroreceptor reflex is preserved → reflex tachycardia helps restore CO -Less hypotension than propofol Respiratory -Respiratory depression → shifts the CO2 response curve to the right -Histamine release can cause bronchoconstriction → caution with asthma

What are the cardiovascular and respiratory effects of midazolam?

Cardiovascular -Sedation dose: Minimal effects -Induction dose: Decreased BP and decreased SVR Respiratory -Sedation dose: Minimal effects -Induction dose: Respiratory depression -Opioids potentiate the respiratory depression -Patients with COPD are more sensitive to the respiratory depressant effects

What is the cause of transient neurologic symptoms? -What factors increase the risk?

Cause -Patient positioning, stretching of the sciatic nerve, myofascial strain, muscle spasm Factors that increase risk -Lidocaine, lithotomy postion, ambulatory surgery, knee arthroscopy

What structures are anesthetized by a celiac plexus block? -How about a superior hypogastric block?

Celiac Plexus Block -Innervates the upper abdominal viscera, NOT the pelvic organs -Useful for pain from the upper abdominal organs (cancer patients) Superior Hypogastric Plexus Block -The superior hypogastric plexus innervates the pelvic organs -Blockade of the superior hypogastric plexus is useful with pain involving the pelvic organs (cancer patients)

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

Contrast the location and function of the central and peripheral chemoreceptors.

Central Chemoreceptor -Located in the medulla -Responds to the H+ concentration in the CSF (a function of the PaCO2 in blood) Peripheral Chemoreceptors -Located in the carotid bodies (Nerves of Hering - Glossopharyngeal n.) -Located in the aortic arch (Vagus n.) -Respond to decreased O2, increased CO2, and increased H+

What complication can result when hypertonic saline is administered too quickly?

Central pontine myelinolysis

Define restrictive lung disease.

Characterized by: -Impaired lung expansion -Decreased lung volumes -Normal pulmonary flow rates

How does chest wall compliance change in the elderly?

Chest wall compliance decreases. The chest is stiffer and more difficult to expand. -Flatter diaphragm -Increased A:P diameter -Increased intercostal muscle mass -Joint calcification -Loss of intervertebral disc height

Discuss the association between insulin and allergic reactions.

Chronic NPH use (or fish allergy) may sensitize the patient to protamine. This may not manifest until a large dose of protamine is administered

Why did we include an asterisk on the narrowest region of the infant airway?

Classic teaching -Infant = Narrowest at the cricoid ring & funnel shaped airway -Adult = Narrowest at the vocal cords & cylinder shaped airway *The narrowest non-displacible portion of the pediatric airway is the cricoid cartilage, the glottis is actually more narrow, but it can be easily displaced

Compare and contrast the diagnostic criteria for gestational HTN, preeclampsia, and eclampsia.

Classic triad of preeclampsia → hypertension after 20 weeks gestation, proteinuria, and generalized edema

Discuss the clinical presentation and treatment of epiglottis.

Clinical presentation -High fever -Tripod position helps breathing -4 D's: Drooling, dysphonia, dyspnea, dysphagia Treatment -O2 -Urgent airway management → intubation or tracheostomy -Abx (if bacterial) -Induction with spontaneous ventilation (CPAP 10-15 cmH2O) -ENT surgeon must be present -Post-op ICU care

Discuss the clinical presentation and treatment of croup.

Clinical presentation -Mild fever -Inspiratory stridor -Barking cough Treatment -O2 -Racemic epinephrine -Corticosteroids -Humidification -Fluids -Intubation rarely required

How does succinylcholine affect intragastric pressure?

Contraction of the abdominal muscles increases intragastric pressure. At the same time, succinylcholine raises lower esophageal sphincter tone → these cancel each other out → no risk of aspiration

List the contraindications and controversial uses for intraoperative blood salvage.

Contraindications -Sickle cell disease -Thalassemia -Topical drugs in sterile field (butadiene, chlorhexidine, antibiotics) -Infected surgical site -Oncologic procedures -Use during cesarean section is controversial (AFE)

What is the origin of the efferent PNS pathways?

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)

How does Cushing's syndrome present? -Why?

Cushing's syndrome → glucocorticoid, mineralocorticoid, and androgenic effects Glucocorticoid effects -Hyperglycemia -Weight gain -Increased risk of infection -Osteoporosis -Muscle weakness -Mood disorder Mineralocorticoid effects -Hypertension (Na+ and water retention) -Hypokalemia (K+ wasting) -Metabolic alkalosis (K+ wasting) Androgenic effects -Women become masculinized, men become feminized

What is Cushing's triad? -What is the clinical relevance of this reflex?

Cushing's triad -Hypertension → Effort to preserve cerebral perfusion -Bradycardia → Baroreceptor reflex from HTN -Irregular respirations → Compression of the medulla

What are the 2 classifications of spinal needles?

Cutting tip and non-cutting tip (pencil point & rounded bevel)

What determines local anesthetic onset of action? -Which drug disobeys this rule and why?

-pKa determines onset of action -If the pKa is closer to the pH, the onset is faster -If the pKa is further from the pH, the onset is slower -Chloroprocaine disobeys this rule - High pKa, which usually means a slow onset - however, we give a higher concentration (3%) which has a rapid onset due to mass effect

Where is vWF synthesized and what is its function?

-vWF is synthesized by the vascular endothelium and megakaryocytes -It anchors the platelet to the vessel wall at the site of vascular injury (platelet adhesion) -It carries inactivated factor VIII in the plasma

What coagulation factors are NOT produced by hepatocytes?

-vWF: Vascular endothelial cells -Factor III (tissue factor): Vascular endothelial cells -Factor IV (Ca+2): Diet -Factor VIII (antihemophilic factor): Liver sinusoidal cells and endothelial cells

Know the pressure conversion factors.

1 ATM = 760 mmHg = 760 torr = 1 bar = 100 kPa = 1033 cmH2O = 14.7 lb/inch^2

What is a MAC hour?

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

What is Avogadro's number?

1 mole of any gas is made up of 6.023 x 10^23 atoms

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

1. Adhesion 2. Activation 3. Aggregation

List 3 conditions that set afterload proximal to the systemic circulation.

1. Aortic stenosis 2. Hypertrophic cardiomyopathy 3. Coarctation of the aorta

What are 2 risks of pressing the oxygen flush valve?

1. Barotrauma -Pressing the O2 flush valve during inspiration 2. Awareness Dilution of the partial pressure of the volatile agent

What are the 5 determinants of cerebral blood flow?

1. Cerebral metabolic rate for O2 (CMRO2) 2. Cerebral perfusion pressure 3. Venous pressure 4. PaCO2 5. PaO2

List 4 clinical indications for isoproterenol.

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

List 6 conditions that are NOT definitively linked to MH.

1. Duchenne muscular dystrophy 2. Becker muscular dystrophy 3. Neuroleptic malignant syndrome 4. Myotonia congenita 5. Myotonic dystrophy 6. Osteogenesis imperfecta

List 3 ways to inhibit acetylcholinesterase. Give examples of each.

1. Electrostatic attachment → Edrophonium 2. Formation of caramel esters → Neostigmine, pyridostigmine, physostigmine 3. Phosphorylation → Organophosphates and echothiophate (non-competitive)

Describe the Starling forces in the context of capillary fluid transfer.

1. Forces that move fluid from the capillary to the interstitium -Pc = Capillary hydrostatic pressure - pushes fluid out of the capillary -π if = Interstitial oncotic pressure - pulls fluid out of the capillary 2. Forces that move fluid from the interstitium into the capillary -Pif = Interstitial hydrostatic pressure - pushes fluid into the capillary π c = Capillary oncotic pressure - pulls fluid into the capillary

What are the two most significant risks associated with sugammadex?

1. Hypersensitivity 2. Concern about the ability to re-paralyze patient with an aminosteroidal NMB -A larger dose of paralytic may be required, it will have a longer onset and shorter duration *Instead, just choose a benzylisoquinolinium compound instead.

What are 2 common ways of reducing ICP that should be specifically avoided in patients with traumatic brain injury?

1. Hyperventilation can worsen cerebral ischemia in patients with TBI 2. Steroids worsen outcome in TBI

What hemodynamic conditions reduce cardiac output in the patient with hypertrophic cardiomyopathy?

1. Increased HR or contractility 2. Decreased preload 3. Decreased afterload

What are the 3 phases of the contemporary cell-based coagulation cascade?

1. Initiation 2. Amplification 3. Propagation

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

1. Jugular compression secondary to improper head positioning 2. Increased intrathoracic pressure secondary to coughing or PEEP 3. Vena cava thrombosis 4. Vena cava syndrome

Identify 3 conditions that are definitively linked to MH.

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 are the 3 most common causes of intraoperative anaphylaxis?

1. Neuromuscular blockers (Sch most common) 2. Latex 3. Antibiotics

Discuss the nitric oxide pathway of 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)

What are the 5 tasks of oxygen in the anesthesia machine?

1. O2 pressure failure alarm 2. O2 pressure failure device (failsafe) 3. O2 flowmeter 4. O2 flush valve 5. Ventilator drive gas

Give 4 examples of how the hypoxia prevention safety device might permit the delivery of a hypoxic mixture.

1. Oxygen pipeline crossover 2. Leaks distal to the flowmeter valves 3. Administration of a third gas (helium) 4. Defective mechanic or pneumatic components

How do you perform a Bier block?

1. Place a double cuff tourniquet on the patient, do not inflate it 2. Place a 22g PIV in a distal peripheral vein 3. Elevate the extremity for 1-2 minutes to allow for passive exsanguination, then wrap the Esmarch bandage around the extremity to further exsanguinate it. Begin at the distal limb and move proximally until you reach the distal tourniquet cuff 4. Inflate the DISTAL cuff → this helps further exsanguinate the arm 5. Inflate the PROXIMAL cuff 6. Deflate the DISTAL cuff 7. Remove the Esmarch bandage 8. Inject a large volume of dilute LA, such as 50 mL 0.5% lidocaine

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

1. Precordial stethoscope 2. Visual inspection of chest rise 3. Capnography 4. Respiratory volume monitors 5. Low expired volume alarm 6. Low peak pressure alarm 7. Failure of bellows to rise or fall *4 ways to monitor for circuit disconnect → pressure, volume, EtCO2, vigilance

What are the 3 possible configurations of the voltage-gated sodium channel?

1. Resting: The channel is closed and able to be opened if the neuron depolarizes 2. Active: The channel is open and Na+ is moving along its concentration gradient into the neuron 3. Inactive: The channel is closed and unable to be opened

What are the 3 ways that NE can be removed from the synaptic cleft? -Which are the most important?

1. Reuptake into the presynaptic neuron (accounts for 80%) 2. Diffusion away from the synaptic cleft 3. Reuptake by extra neural tissue

What are the 4 defects associated with tetralogy of Fallot?

1. Right ventricular outflow obstruction 2. Right ventricular hypertrophy due to high venous pressure load from RV obstruction 3. Ventricular septal defect due to septal malalignment 4. Overriding aorta that receives blood from both ventricles

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

List 5 factors that govern the uptake and plasma concentration of local anesthetics.

1. Site of injection 2. Tissue blood flow 3. Physiochemical properties of the LA 4. Metabolism 5. Addition of vasoconstrictor

What is the treatment plan for an acute hemolytic reaction?

1. Stop the transfusion 2. Maintain urine output > 75-100 mL/hr → IV fluids, mannitol, furosemide 3. Alkalinize the urine with sodium bicarbonate 4. Send urine and plasma hemoglobin samples to blood bank 5. Check platelets, PT, and fibrinogen 6. Send unused blood to blood bank to double check cross match 7. Support hemodynamics with IVF and pressors as needed

What 3 things can increase the risk of contractions in the patient with myotonic dystrophy?

1. Succinylcholine 2. Reversal of NMB with anticholinesterases 3. Hypothermia (shivering → sustained contraction)

What are the 3 key determinants of flow through the left ventricular outflow tract?

1. Systolic LV volume 2. Force of LV contraction 3. Transmural pressure gradient

Discuss excitation-contraction coupling in the cardiac myocyte.

1. The myocardial cell membrane depolarizes 2. During the plateau of the ventricular action potential (phase 2), Ca+2 enters the cardiac myocyte through L-type Ca+2 channels in the T-tubules 3. Ca+2 influx turns on the RYR2 receptor, which releases Ca+2 from the sarcoplasmic reticulum (Ca+2 induced Ca+2 release) 4. Ca+2 binds to troponin C (myocardial contraction) 5. Ca+2 unbinds from troponin C (myocardial relaxation) 6.Most of the Ca+2 is returned to the SR via the SERCA2 pump

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

1. The placenta is the organ of respiration (adult = lungs) 2. The circulation is arranged in parallel (adult = series) 3. Right-to-left shunting occurs across the foramen oval and ductus arteriosus 4. PVR is high - the lungs are collapsed and filled with fluid, so there is very little pulmonary flow 5. SVR is low - the placenta provides a large, low resistance vascular bed

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

1. Turn ON the oxygen cylinder 2. Disconnect the pipeline oxygen supply -If a crossover occurs and adequate oxygen pipeline pressure is present, it will prevent the O2 tank from providing O2 to the patient

How do we establish an anesthetic concentration inside the alveolus?

1. Turn the vaporizer on. This creates a concentration gradient that pushes anesthetic agent from he vaporizer towards the alveoli → this is FI 2. Ventilation washes the anesthetic agent into the alveoli → this is FA 3. The buildup of anesthetic partial pressure inside the alveoli is opposed by continuous uptake of agent into the blood → this is uptake 4. The cardiac output distributes the anesthetic agent thought 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

Which local anesthetic can reduce the efficacy of epidural opioids?

2-Chloroprocaine reduces the efficacy of epidural opioids

How do you block the radial nerve in the forearm?

3-5 mL of LA is injected between the biceps tendon and brachioradialis

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 (C6-T1) -Radial (C5-T1) -Ulnar (C8-T1)

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

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

The bourdon pressure gauge on an oxygen cylinder ready 500 psi. If the flow rate is 4 L/min, how long will this cylinder provide O2 to the patient?

660 L/1900 psi = x/500 psi = 174 L or 43.5 minutes

Define hypopnea.

A 50% reduction in airflow for 10 seconds, 15 or more times per hour, and is linked to snoring and decreased oxygen saturation

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

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 we keep the patient in the sitting position after the block, a hyperbaric solution will sink and anesthetize the sacral nerve roots - this is a saddle block. -If we lay the patient supine after the block, a hyperbaric solution will slide down he lumbar lordosis and eventually pool in the sacrum and thoracic kyphosis (T4)

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

A hypobaric solution will settle to the highest point of the spinal canal -If we keep the patient in the sitting position after the block, a hypobaric solution will rise towards the brain - this isn't a good idea -If we inject a hypobaric solution and then place the patient supine, the solution will float towards the lower lumbar region. It does not float towards the cervical region, because this would first require the local anesthetic to sink into the thoracic kyphosis.

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

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

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

What is an adiabatic process?

A process that occurs without gain or loss of energy, for example a very rapid expansion of a gas were there is no transfer of energy

What is the treatment for a total spinal?

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

What are Van der Waals forces?

A very weak intermolecular force that holds molecules of the same type together -Weakest type of molecular attraction

Describe the relationship of the terminal branches relative to the axillary artery.

The axillary block targets four terminal branches of the brachial plexus -Musculocutaneous nerve is anterior and lateral -Median nerve is anterior and medial -Radial nerve is posterior and lateral -Ulnar nerve is posterior and medial

What are the 5 main components of the brachial plexus?

The brachial plexus is divided into 5 components -Roots = 5 -Trunks = 3 -Divisions = 6 -Cords = 3 -Branches = 5 Pneumonic → Reach To Drink Cold Beer

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 → increased risk of needle injury or cannulation during neuraxial techniques

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.

Discuss the anatomy of the femoral triangle.

The femoral nerve arises from he posterior divisions of L2-L4. After these nerve roots exit the spinal column, they give rise to the femoral nerve within the psoas major. The femoral nerve stays in the groove between the psoas major and iliac muscle before entering the femoral triangle -Femoral nerve runs deep to the inguinal ligament, anterior to the iliopsoas muscle, and inferior to the fascia late and fascia iliaca

What components are present in the high pressure system the anesthesia machine? -What is the gas pressure in this region?

The high pressure system begins at the cylinder and ends at the cylinder regulators. -Hanger yoke -Yoke block with check valves -Cylinder pressure gauge -Cylinder pressure regulators -Gas pressure = Cylinder pressure

What is the gastric barrier pressure? Why is it important?

The higher the barrier pressure, the lower the likelihood of reflux

What is critical temperature and how does this apply to gas cylinders?

The highest temperature where a gas can exist as a liquid -The critical temperature for N2O is 36.5, which explains why it primarily exists as a liquid inside the cylinder

What is the function of the ideal gas law?

The ideal gas law unifies all 3 gas laws into a single equation -PV = nrT -n = number of moles -r = constant 0.0821 liter-atm/K/mole

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

The imidazole ring can assume the open or closed position, depending upon environmental pH -Acidic pH → imidazole ring opens → increased water solubility -Physiologic pH → imidazole ring closes → increased lipid solubility

What types of surgical procedures are well suited for an infraclavicular block? -Which are not?

The infraclavicular approach is a cord-level block. -This approach covers the upper extremity below the elbow, the shoulder and upper arm are not anesthetized

Describe the pathophysiology of the insulin receptor.

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. The insulin cascade turns on the GLUT4 transporter, which increases glucose uptake by skeletal muscles and fat.

What components are present in the intermediate pressure system of the anesthesia machine?

The intermediate pressure system begins at the pipeline and ends at the flowmeter valve -Pipeline inlets -Pressure gauges -Ventilator power inlet -Oxygen pressure failure system -Oxygen second stage regulator -Oxygen flush valve -Flowmeter valve -Gas pressure = 50 psi (pipeline) or 45 psi (tank)

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 BP control -Long term BP control is carried out by the thirst mechanism and Na+ and water excretion -Intermediate BP control is carried out by the RAAS -Short term BP control is carried out by the baroreceptor reflex

How much blood flow do the kidneys receive (percentage of CO and total flow)?

The kidneys receive 20-25% of cardiac output → 1000-1250 mL/min

How does obesity affect the dosing of propofol?

The loading dose of propofol is based on lean body weight -Induction → LBW -Maintenance → TBW

What is critical pressure?

The minimum pressure required to convert a gas to a liquid at its critical temperature

What is post-retrobulbar block apnea syndrome?

The optic nerve is the only cranial nerve that is part of the CNS -Local anesthetic inject into the optic sheath is permitted direct entry to the brain - just like giving a subarachnoid block

What does the oxygen analyzer measure? -Where is it located?

The oxygen analyzer monitors 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

Where is the pituitary gland located? -What is another name for the anterior and posterior pituitary gland?

The pituitary gland resides in the sella turcica and is connected to the hypothalamus by the pituitary stalk -Anterior pituitary = Adenohypophysis -Posterior pituitary = Neurohypophysis

What determines how much blood is delivered to the portal vein?

The portal vein receives venous blood that has passed through the splanchnic circulation

Define vaporization.

The process by which a liquid is converted to a gas → requires energy

What conditions increase the risk of abnormal placental implantation?

The risk of abnormal implantation is closely associated with placenta previa and previous cesarean sections

What is the primary determinant of cardiac output in the patient with a heart transplant? -What is the consequence of this?

The transplanted heart is severed from autonomic influence, so the heart rate is determined by the intrinsic rate of the SA node - many of these patients have resting tachycardia - 100-120 bpm -Cardiac output becomes dependent upon preload, these patients are very sensitive to hypovolemia

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 → Second gas effect

What are the 3 most important inputs to the vomiting center? -What receptors are involved in each one?

The vomiting center resides in the nucleus tracts solitaires. Sensory input arises from the: -CTZ -GI tract -Vestibular system

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

There are 3 cords → posterior, lateral, medial -C5-C7 → Anterior divisions of superior and middle trunks → lateral cord -C8-T1 → Anterior division of inferior trunk → medial cord -C5-T1 → All 3 posterior divisions → posterior cord

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

There are 3 trunks → superior, middle, inferior -C5-6 → superior trunk -C7 → middle trunk -C8-T1 → inferior trunk

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

There are 6 divisions → 3 posterior & 3 anterior -C5-C7 → Anterior divisions of superior and middle trunks -C8-T1 → Anterior division of inferior trunk -C5-T1 → All 3 posterior divisions

What is the risk of a neuraxial technique in the patient with intracranial hypertension?

There is an increased chance of brain herniation with sudden change in CSF pressure

Describe the mechanism of action, clinical use, and key side effects of thiazide diuretics.

Thiazide diuretics -Hydrochlorothiazide -Metolazone -Indapamide MOA -Thiazides inhibit the Na-Cl transporter in the distal tubule Clinical uses -HTN -CHF -Osteoporosis (reduces Ca+2 excretion) -Nephrogenic diabetes insipidus Key side effects -Hyperglycemia -Hypercalcemia -Hyperuricemia -Hypokalemic, hypochloremic metabolic alkalosis -Hypovolemia

What are the 2 sub-classes of barbiturates? -List examples of each.

Thiobarbiturates -There is a sulfur molecule in the second position -Ex: thiopental, thiamylal Oxybarbiturates -There is an oxygen molecule in the second position -Ex: methohexital, pentobarbital

What is the origin of the efferent SNS pathways?

Thoracolumbar -T1-L3 -Cell bodies arise from the intermediolateral region of the spinal cord and axons exit via the ventral nerve roots. -Preganglionic fibers usually synapse with postganglionic fibers in the 22 paired sympathetic ganglia (mass effect)

How does thyroid hormone affect cardiac function?

Thyroid hormone is independent of the ANS -Increased chronotropy, inotropy, lusitropy -Decreased SVR -Increased number and sensitivity of cardiac beta receptors, decreased number of cardiac muscarinic receptors

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 valvular defect is highly suggestive of pulmonary HTN in the obese patient?

Tricuspid regurgitation

Describe the sensory innervation of the upper airway

Trigeminal -V1 (Ophthalmic) = Nares and anterior 1/3 of septum -V2 (Maxillary) = Turbinates and septum -V3 (Mandibular) = Anterior 2/3 of tongue Glossopharyngeal -Posterior 1/3 of tongue -Soft palate -Oropharynx -Vallecula -Anterior side of epiglottis Superior laryngeal -Internal branch = posterior side of epiglottis to the level of the vocal cords -External branch = 0 sensory function, motor innervation to the cricothyroid muscle Recurrent laryngeal -All intrinsic muscles except the cricothyroid

What is the treatment for cerebral vasospasm?

Triple H therapy → Hypervolemia, hypertension, and hemodilution (Hct 27-32%) -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

Describe aspiration prophylaxis for the patient scheduled for a cesarean section.

Triple prophylaxis against aspiration -Sodium citrate to neutralize gastric acid -H2 receptor antagonist (ranitidine) to reduce gastric acid secretion -Gastrokinetic agent (metoclopramide) to hasten gastric emptying and increase LES tone

Why are extrajunctional receptors sometimes called fetal receptors?

Two pathologic variants of the nicotinic receptor; The traditional subtype in lieu of an epsilon subunit, and a 7-alpha subtype that consists of 5 alpha subunits -Extrajunctional receptors resemble those that are present early in fetal development, once innervation takes place, the fetal nicotinic receptors are replaced by the adult subtype -Denervation later in life allows for the return of both types of exntrajunctional receptors

Discuss fade in the context of succinylcholine and non-depolarizing neuromuscular blockers.

Two supplies of Ach vesicles: 1. Ach that is available for immediate release 2. Ach that must be mobilized before it can be made available for immediate release -Nondepolarizing neuromuscular blockers competitively antagonize the presynaptic Nn receptors, which impairs the mobilization process. -Succinylcholine stimulates the pre junctional receptors → it has the same effect as Ach. It binds to the presynaptic Nn receptor and facilitates the mobilization process → no fade

What is the defining characteristic between type I and type II complex regional pain syndrome?

Two types of CRPS: -Type I: Reflex sympathetic dystrophy - no nerve injury -Type II: Causalgia - nerve injury

How does uncontrolled labor pain affect the fetus? -Why?

Uncontrolled pain can result in: -Increased maternal catecholamines → HTN → reduced uterine blood flow -Maternal hyperventilation → leftward shift of oxyHgb curve → reduced delivery of O2 to the fetus

Where do the trunks turn into divisions?

Underneath the clavicle and over the 1st rib

What cardiac pathologies present a risk of hemodynamic collapse with neuraxial anesthesia?

Valve lesions with a fixed stroke volume -Severe aortic stenosis -Severe mitral stenosis -Hypertropic cardiomyopathy

What is the primary determinant of spread for epidural anesthesia?

Volume

Describe the pathophysiology of pyloric stenosis.

Vomiting depletes water → hyponatremic, hypokalemic, hypochloremic metabolic alkalosis *Metabolic acidosis is a late complication!

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 can we apply Poiseuille's law to the administration of a unit of packed red blood cells?

We can deliver PRBCs faster if we: -Increase the radius with a large bore IV -Increase the pressure gradient with a pressure bag and/or increase the height of the pole -Decrease the viscosity by diluting the blood with 0.9% NaCl and or running it through a fluid warmer -Decrease the length by not using longer tubing than you really need

Where do divisions turn into cords?

When the brachial plexus goes under the pectorails minor muscle

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

While its existence remains controversial, many speculate that a band of connective tissue courses between the ligamentum flavum and the dura mater. If it does exist, it could conceivably create a barrier that would impact spread of medications within the epidural space -Considered the culprit for unilateral epidural blocks

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 non depolarizing block?

Yes, they should receive a muscarinic antagonist with an AchE inhibitor just like everyone else

Define the West zones of the lung

Zone I -PA > Pa > Pv -Dead space - ventilation without perfusion Zone II -Pa > PA > Pv -Waterfall - normal physiology Zone III -Pa > Pv > PA -Shunt - perfusion without ventilation Zone IV -Pa > Pist > Pv > PA -Pressure in the interstitial space impairs ventilation and perfusion

How do you calculate changes in plasma protein binding?

[Free drug] + [Unbound protein binding sites] = [Bound drug] -Ex: If a drug is 98% bound and the bound fraction is reduced to 96%, the unbound or free fraction has increased by 100% (2% → 4%)

Rank the IV opioids in terms of potency.

sufentanil > fentanyl = remifentanil > alfentanil > hydromorphone > morphine > meperidine

How does hypothyroidism affect gastric emptying?

Delayed gastric emptying → increased risk of aspiration

What are the signs, symptoms, and treatment for delirium tremens?

Delirium tremens occurs after 2-4 days without alcohol -S/Sx: Grand mal seizures, tachycardia, hyper or hypotension -Treatment: Diazepam (or other benzodiazepine) and beta blockers

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

Depolarizing NMB's -Succinylcholine -Mivacurium Ester-type LA's -Chloroprocaine -Tetracaine -Procaine -Benzocaine -Cocaine

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

Determinants of delivery -Setting on the vaporizer -Time constant of the delivery system -Anatomic dead space -Alveolar ventilation -FRC Determinants of uptake -Solubility of anesthetic in the blood (blood:gas partition coefficient) -Cardiac output -Partial pressure gradient between alveolar case and mixed venous blood

What endocrine disorder can occur after transphenoidal resection of pituitary gland?

Diabetes insipidus → too little ADH

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

Difference between alveolar oxygen and arterial oxygen. -It helps us diagnose the cause of hypoxemia by quantifying the amount of venous admixture -Normally 5-15 mmHg -Increased by high FiO2, aging, vasodilators, right-to-left shunting, and diffusion limitation

Explain diffusion hypoxia.

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

What is the mechanism of action of propofol?

Direct GABA-A agonist → increased Cl- conductance → neuronal hyperpolarization

What is the risk of distilled water when used for irrigation during TURP?

Distilled water has an osmolality of zero. This creates a dilutional effect that increases the risk of hyponatremia, hypoosmolality, hemolysis, and hemoglobinuria (renal failure)

Describe the pathophysiology of Parkinson's disease.

Dopaminergic neurons in the basal ganglia are destroyed

Compare the structure and function of the dorsal column with the spinothalmic tract.

Dorsal column - Medial lemniscal system (more evolved system) -Transmits mechanoreceptive sensations: fine touch, proprioception, vibration, and pressure -Capable of two point discrimination -Consists of large, myelinated, rapidly conducting fibers -Transmits sensory information faster than the anterolateral system Anterolateral System - Spinothalamic Tract (more primitive system) -Transmits: Pain, temperature, crude touch, tickle, itch, and sexual sensation -Two point discrimination is not present -Consists of smaller, myelinated, slower conducting fibers

What is the dose for PRBC transfusion in the neonate? -How much will this increase Hgb?

Dose = 10-15 mL/kg -10 mL/kg will raise Hgb by 1-2 g/dL

What is the dose for FFP transfusion in the neonate?

Dose = 10-20 mL/kg

How do you dose nondepolarizing neuromuscular blockers in the neonate? -Why?

Dose = same as adults on a mg/kg basis -ECF is larger, but the NMJ is more sensitive to the effects of nondepolarizers

What factors decrease MAC?

Drugs -Acute alcohol intoxication -IV anesthetics -N2O -Opioids -Alpha-2 agonists -Lithium -Lidocaine Electrolytes -Hyponatremia Age -Older age -Prematurity Body Temperature -Hypothermia Other -Hypotension -Hypoxia -Anemia -Metabolic acidosis -Pregnancy → Postpartum (24-72 hours)

What factors increase MAC?

Drugs -Chronic alcohol consumption -Acute cocaine/amphetamine intoxication -MAOIs -Ephedrine -Levodopa Electrolytes -Hypernatremia Age -Increased in infants 1-6 months Body Temperature -Hyperthermia Other -Red hair

Give the name, location, and function of the 3 fetal shunts.

Ductus venosus: -Function - Allows umbilical blood to bypass the liver -Location - Umbilical vein → inferior vena cava Foramen ovale: -Function - Shunts blood from RA to LA to bypass lungs to perfuse the upper body -Location - Right atrium → left atrium Ductus arteriosus: -Function - Shunts blood from the pulmonary trunk to the aorta -Location - Pulmonary artery → proximal descending aorta

When does each fetal shunt close? -What is the adult remnant of each?

Ductus venous -Closes - Clamping of the umbilical cord -Remnant - Ligamentum venosus Foramen ovale: -Closes - 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 → treat hyperglycemia with insulin

Describe how extracorporeal shock wave lithotripsy breaks up kidney stones.

ESWL delivers shock waves in rapid succession that are directed at the stone -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 and producing smaller stone fragments that are eliminated via the urine *There is nothing between the energy source and the stone

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

Discuss the pathophysiology of Ehlers-Danlos syndrome.

Ehlers-Danlos syndrome is an inherited disorder of pro collagen and collagen. There are severe types, but only type IV is associated with blood vessel rupture. -There is an increased bleeding tendency, this is the result of a lack of blood vessel integrity, not coagulopathy -Avoid all regional and IM injections -Pneumothorax is a common complication.

What factors do not affect MAC?

Electrolytes -Hyper or hypokalemia -Hyper or hypomagnesemia Other -Hyper or hypothyroidism -Gender -HTN -PaCO2 - 15-95 mmHg

How does obesity affect the dosing of an epidural?

Engorgement of the epidural veins and an increased epidural fat content will cause a greater spread of LA in the epidural space → dose should be reduced to 75% of normal dose

Discuss enterohepatic circulation and list 1 drug example.

Enterohepatic circulation → Some conjugated compounds are excreted in the bile, reactivated in the intestine, and then reabsorbed into systemic circulation -Ex: Diazepam

What are the 3 different types of epidural needles? -How are they different from each other?

Epidural needles differ in the angle of the needle tip. Notice that the needle angle increase in alphabetical order. -Crawford = 0 degrees -Hustead = 15 degrees -Tuohy = 30 degrees -Tuohy needle has the most pronounced curvature → this curvature plus its blunt tip helps prevent dural puncture

Contrast the regions affected by epiglottitis and croup. -How do these present on a lateral neck x-ray?

Epiglottitis -Region affected → supraglottic structures -Lateral neck x-ray → swollen epiglottitis (Thumb sign) Croup -Region affected → laryngeal structures -Lateral neck x-ray → subglottic narrowing (Steeple sign)

What stimulates the kidney to release erythropoietin? -What does EPO do after it is released?

Erythropoietin is released in response to inadequate O2 delivery to the kidney (anemia, hypovolemia, hypoxia) -EPO stimulates stem cells in the bone marrow to produce erythrocytes -Severe kidney disease reduces EPO production and leads to chronic anemia

Discuss the etiology, presentation, and prevention of femoral nerve injury.

Etiology -Excessive traction during lower abdominal surgery Presentation -Impaired knee extension and hip flexion -Reduced sensation over the anterior thigh and anteromedial aspect of the leg Prevention -Avoid excessive traction during lower abdominal surgery

Discuss the etiology, presentation, and prevention of sciatic nerve injury.

Etiology -Lithotomy - Extreme hip flexion and/or external rotation of the legs -Sitting - Straight legs Prevention -Ample padding under buttocks -Avoid excessive external rotation of the hips -Flex table at the knees Presentation -Foot drop

Discuss the etiology, presentation, and prevention of saphenous nerve injury.

Etiology -Medial aspect of the leg leans against the supporting cradle in the lithotomy position Prevention -Place padding between leg and stirrup Presentation -Reduced sensation over the anteromedial aspect of the leg

Discuss the etiology, presentation, and prevention of peroneal nerve injury.

Etiology -The common peroneal nerve is highly susceptible to injury when the patient is placed in stirrups. The nerve wraps around the fibular head and can be composed when the lateral aspect of the leg leans against the stirrup bar Presentation -Foot drop -Inability to evert the foot -Inability to extend the toes dorsally Prevention -Place padding between the leg and stirrup -Place pad under the fibular head -Knees should be flexed with minimal rotation

Discuss the etiology, presentation, and prevention of obturator nerve injury.

Etiology: -Excessive flexion of the thigh towards the groin -Excessive traction during lower abdominal surgery -Forceps delivery Presentation -Inability to adduct the leg -Reduced sensation over the medial aspect of the thigh Prevention -Minimize hip flexion

What is the Child-Pugh score?

Examines 5 factors of hepatic function: Albumin, PT, bilirubin, ascites, and encephalopathy -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 -A or B can go to surgery, C should be optimized before surgery

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

Give examples of extrinsic lung diseases (chest wall disorders and increased intraabdominal pressure disorders).

Extrinsic lung disease - Affects areas around lungs -Chest wall/mediastinum: kyphoscoliosis, flail chest, neuromuscular disorders, mediastinal mass -Increased intraabdominal pressure: pregnancy, obesity, ascites

What tests can measure FRC?

FRC is measured indirectly by nitrogen washout, helium wash in, or body plethysmography

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 patient with thromboembolism require anticoagulation, lifelong anticoagulation is unwarranted unless recurrent thrombotic events are experienced

How does obesity affect the dosing of opioids?

Fent/Sufent -Loading → TBW -Maintenance → LBW Remi -Loading → LBW -Maintenance → LBW

Describe the Parkland formulas for resuscitation in burn patients.

First 24 hours -Crystalloid = 4 mL LR x %TBSA burned x kg (1/2 in first 8 hours, 1/2 in next 16 hours) -Colloid = none Second 24 hours -Crystalloid = D5W at a normal maintenance rate -Colloid = 0.5 mL x %TBSA x kg

Compare and contrast the pain that results from the first and second stages of labor.

First stage: Pain begins in the lower uterine segment of the cervix → origin T10-L1 posterior nerve roots Second stage: Adds in pain impulses form the vagina, perineum, and pelvic floor → origin S2-S4 posterior nerve roots

List 1 drug that is bioransformed by alkaline phosphatase hydrolysis.

Fospropofol

Which type of evoked potential is the most sensitive to the effects of volatile anesthetics? -Which is the most resistant?

From most to least sensitive to volatile anesthetics -VEP > SSEP/MEP > BEP -Visual evoked potentials are the most sensitive -Brainstem evoked potentials are the most resistant

What is the mechanism of action for midazolam?

GABA-A agonist → Increased frequency of channel opening → neuronal hyperpolarization *Most GABA-A agonist increase channel open time, but benzodiazepines increase open frequency

Explain the Joule-Thompson effect in the context of gas cylinders.

Gas stored at high pressure that si suddenly released escapes from its container into a vacuum. It quickly loses speed as well as a significant amount of energy → results in a fall in temperature -Ex: O2 cylinder opened too quickly feels cool to the touch

How do general and neuraxial anesthesia affect hepatic blood flow?

General and neuraxial anesthesia reduce liver blood flow as a function of decreased MAP

How does the kidney eliminate toxins and metabolites?

Glomerular filtration and tubular secretion clear the blood of metabolic byproducts, toxins, and drugs -The kidney is capable of phase I and II biotransformation

How can acetaminophen cause hepatic injury? -What is the treatment?

Glutathione is a substrate for many phase 2 conjugation reactions, it increases a substance's water solubility -Acetaminophen produces a toxic metabolite calle N-acetyl-p-benzoquinoneimine -With normal acetaminophen dosing → the metabolite is conjugated with glutathione -Acetaminophen overdose consumes the liver's supply of glutathione Treatment -Oral n-acetylcysteine within 8 hours of acetaminophen overdose

What is the risk of glucose when used for irrigation during TURP?

Glycine metabolism can increase ammonia production, which reduces LOC and contributes to encephalopathy -Glycine can cause blindness or blurry vision for 24-48 hours

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

Goiter = awake intubation -Next best → technique that maintains spontaneous ventilation

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

Guarded receptor hypothesis → Local anesthetics can only bind to sodium channels in their active and inactive states. LA's cannot bind to sodium channels in their resting states. -Use-dependent or phasic blockade → LA's are more likely to bind to axons that are conducting AP's and less likely to bind to those that are not conducting AP's

What is hypoxic pulmonary vasoconstriction? -What is the trigger? How long does it take to begin?

HPV minimizes shunt by reducing blood flow through poorly ventilated alveoli. -A low alveolar PO2 is the trigger that activates HPV. The effect begins almost immediately and reach its full effect after 15 minutes

How do opioids affect HR, BP, and myocardial function?

Heart rate -Bradycardia is the result of mu stimulation (mu 2 > mu 1) -Meperidine can increase HR Blood pressure -There is a minimal effect on BP in healthy patients -Hypotension with morphine or meperidine is the result of histamine release Myocardial function -Contractility is not affected -Myocardial depression if combined with N2O

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: 1. The rate of spontaneous phase 4 depolarization increases (reaches TP faster) 2. TP becomes more negative 3. RMP becomes less negative -When RMP and TP are close, it's easier for cells to depolarize -When RMP and TP are far, it's harder for cells to depolarize

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 -This response is mediated by adenosine -Severe liver disease impairs this response

Which reflex prevents overinflation of the lungs?

Hering-Breuer inflation reflex

Categorize high, medium, and low risk surgical procedures according to cardiac risk.

High Risk(> 5%) -Emergency surgery -Open aortic surgery -Peripheral vascular surgery -Long surgical procedures with significant fluid shifts/blood loss Intermediate Risk (1-5%) -Carotid endarterectomy -Head and neck surgery -Intrathoracic or intraperiotoneal surgery -Orthopedic surgery -Prostate surgery Low Risk (< 1%) -Endoscopic procedures -Cataract surgery -Superficial procedures -Breast surgery -Ambulatory procedures

List 6 patient factors that warrant antibiotic prophylaxis against infective endocarditis.

Highest risk of developing infective endocarditis 1. Previous infective endocarditis 2. Prosthetic heart valve 3. Unprepared cyanotic congenital heart disease 4. Repaired congenital heart defect if repair is < 6 months old 5. Repaired congenital heart disease with residual defects that have impaired endothelialization at the graft site 6. Heart transplant with valvuloplasty

Describe the cardiovascular changes that accompany cirrhosis.

Hyperdynamic circulation -Decreased SVR and BP → increased CO -Increased RAAS → increased blood volume -Increased peripheral blood flow (shunting) → increased SvO2 -Diastolic dysfunction Portal hypertension -Increased hepatic resistance → back pressure to proximal organs -Esophageal varices → bleeding -Splenomegaly → thrombocytopenia Ascites -Decreased oncotic pressure -Decreased protein binding -Increased volume of distribution -Drainage → hypotension

How does hypermagnesemia affect neuromuscular blockade?

Hypermagnesemia potentiates neuromuscular blockade (Sch and NDNMB's)

What is the relationship between the tonicity of IV solutions and increased ICP?

Hypotonic solution have a lower osmolarity than plasma. These fluids are the same as giving free water, and this free water distributes throughout all of the body compartments. -This is why hypotonic solutions are poor expanders of intravascular volume an why you should never give a hypotonic solution to a patient with increased ICP → cells will swell and increase ICP

Describe the pathophysiology of ischemic optic neuropathy.

ION is a consequence of ischemia to the optic nerve -Ocular perfusion pressure = MAP - Intraocular pressure

A patient suffers from retained placental fragments. -What IV medication can you give to help with the extraction?

IV nitroglycerine provides uterine relaxation for placental extraction

Define vapor pressure.

In a closed container, molecules from a volatile liquid escape the liquid phase and enter the gas phase. Vapor pressure is the pressure on the walls of the container that the molecules exert

Discuss the respiratory effects of neuraxial anesthesia.

In healthy patients, neuraxial anesthesia has negligible effects on minute ventilation, tidal volume, respiratory rate, dead space, and arterial blood gas tensions -Accessory muscle function is reduced. Impairment of the intracoastal muscles (inspiration and expiration) as well as the abdominal muscles will decrease pulmonary reserve. This is particularly important for the patient with severe COPD. -Apnea is usually the result of cerebral hypoperfusion, not phrenic nerve paralysis or high concentration of LA in the CSF

Where do cords turn into terminal branches?

In the axilla

What is the cardiac output in the newborn? -How does this affect pharmacokinetics?

In the newborn, cardiac output is 200 mL/kg/min, which means that drugs are delivered to and removed from the rest of the body at a faster rate than the adult

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 → decreased venous return and CO -Displace the mothers uterus away from the vena cava and aorta -Left lateral displacement 15 degrees should be used for anyone in their 2nd or 3rd trimester

How does thyroid hormone affect the respiratory system?

Increased BMR → Increased O2 consumption → Increased CO2 production → Increased minute ventilation

What conditions affect alpha-1 acid glycoprotein concentration?

Increased concentration -Surgical stress -Myocardial infarction -Chronic pain -Rheumatoid arthritis -Advanced age Decreased concentration -Neonates -Pregnancy

What is the role of inflammation in pain transduction?

Inflammation contributes to: -Reduced threshold to pain stimulus (allodynia) -Increased response to pain stimulus (hyperalgesia)

How do intracardiac shunts affect an inhalation or IV induction?

Inhalation induction -Right-to-left shunt = slower induction -Left-to-right shunt = minimal effect IV induction -Right-to-left shunt = faster induction -Left-to-right shunt = slower induction

How are inhalation anesthetics removed from the body? -For each agent, what percentage is attributed to hepatic metabolism?

Inhaled agents are eliminated from the body in 3 ways 1. Elimination from the alveoli (most important) 2. Hepatic biotransformation 3. Percutaneous loss *Rule of 2's

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

Describe how the respiratory muscles function during the breathing cycle

Inspiration -Diaphragm and external intercostals contract -Accessory muscles include the sternocleidomastoid and scalene muscles Expiration -Exhalation is usually passive -Active exhalation is carried out by the abdominal musculature (rectus abdominis, transverse abdominis, internal obliques, external obliques) -Internal intercostals serve secondary role in active exhalation

Give examples of intrinsic lung diseases (acute and chronic).

Intrinsic lung disease - affects lung parenchyma -Acute: aspiration, NPPE -Chronic: Pulmonary fibrosis, sarcoidosis

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

Irradiation exposes PRBCs to gamma radiation, which disrupts WBC DNA in the donor erythrocytes. This is useful in preventing graft vs. host disease in immunocompromised patients who require transfusion. -Populations who benefit → leukemia, lymphoma, hematopoietic stem cell transplants, DiGeorge syndrome

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

It can be used to: -Insufflate oxygen into the non-ventilated lung -Suction air from the non-ventilated lung It CANNOT be used to: -Ventilate -Suction blood, pus, or secretions from the non-ventilated lung

How does obesity affect the dosing of succinylcholine?

It doesn't, dose on TBW

Where do the roots turn into trunks?

Just beyond the lateral border of the scalene muscles

Compare the equianalgesic dose of ketorolac and morphine.

Ketorolac 30 mg IV = morphine 10 mg IV

What is the function of Kupffer cells?

Kupffer cells remove the bacteria before the blood drains into the vena cava

What is Kussmaul's sign?

Kussmaul's sign indicates impaired right ventricular filling due to a poorly compliant RV or pericardium. Since RV filling is affected, the blood essentially "backs up" which causes JVD and increased CVP -More pronounced during inspiration

Why is a left ventricular vent used during CAB surgery?

LV vent removes blood from the LV, this blood comes from Thespian veins and bronchial circulation (anatomic shunt)

How does lean body mass change in the elderly? -Why is this important?

Lean body mass decreases as a function of reduced muscle mass -Decreased BMR -Decreased TBW -Decreased blood volume -Decreased plasma volume -Decreased Vd -Decreased neuromuscular reserve *Hypothermia sets in faster

Define LD50.

Lethal dose 50: The dose that will produce death in 50% of the population

Chronic consumption of what food can produce a syndrome that resembles hyperaldosteronism?

Licorice ingestion causes a syndrome that resembles Conn's syndrome

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 is the definitive treatment for alpha-1 antitrypsin deficiency?

Liver transplant

Chronic ingestion of which herbal medication can mimic Conn's syndrome?

Locorice

What is the difference between a long and short wavelength laser? -What are the clinical consequences of this?

Long wavelength lasers: Absorb more water and do NOT penetrate deep into tissue - cornea at risk -Short wavelength lasers: Absorb less water and penetrate deeper into tissue - retina at risk

Describe the mechanism of action, clinical use, and key side effects of loop diuretics.

Loop diuretics -Furosemide -Bumetanide -Ethacrynic acid MOA -Loop diuretics 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 reabsorption capacity. Thus, a large volume of dilute urine is excreted. Potassium, calcium, magnesium, and chloride are lost the urine as well Clinical uses -HTN -CHF/Acute pulmonary edema Key side effects -Hypokalemic, hypochloremic metabolic alkalosis -Hypocalcemia -Hypomagnesemia -Hypovolemia -Ototoxicity -Reduced lithium clearance

What components are present in the low pressure system of the anesthesia machine?

Low pressure system begins at the flowmeter tubes and ends at the common gas outlet -Flowmeter tubes (Thorpe tubes) -Vaporizers -Check valves -Common gas outlet -Gas pressure = Slightly above ATM pressure

Describe how obesity creates a greater restrictive ventilatory defect.

Lung inflation is inhibited due to: -Chest fat compresses the rib cage and hinders outward expansion -Abdominal fat shifts the diaphragm cephalic and compresses the lungs -Kyphosis and lordosis develop over time and alter the geometry of the ribcage -The extra weight increases the work of breathing -A rapid and shallow breathing patter provides the most energy efficient way to achieve this goal

How does MAC change in the elderly?

MAC decreases by 6% each decade of life after age 40

How does MAC change during pregnancy?

MAC is decreased by 30-40% due to increased progesterone

What is the calculation for mean arterial blood pressure?

MAP = [SBP + (DBP x 2)] / 3 -Normal = 70-105 mmHg

What is the most common DLT complication?

Malposition of the DLT

Discuss the pathophysiology of Marfan syndrome.

Marfan syndrome is an autosomal dominant trait. It is a connective tissue disorder that's associated with an elevated risk of aortic dissection, mitral valve prolapse, mitral regurgitation, and aortic insufficiency. -Dissection of the ascending aorta can extend into the pericardium and increase the risk of cardiac tamponade. -Spontaneous pneumothorax is a very common complication in the patient with Marfan Syndrome

What is mediastinoscopy and why is it performed?

Mediastinoscopy is performed to obtain biopsy of the paratracheal lymph nods at the level of the carina, this helps the surgeon stage the tumor prior to resection

Describe the 4 areas in the respiratory center.

Medullary Respiratory Centers -Dorsal respiratory center: Active during inspiration (respiratory pacemaker) -Ventral respiratory center: Active during expiration Pontine Respiratory Centers -Pneumotaxic center (upper pons): Inhibits the DRC -Apneustic center (lower pons): Stimulates the DRC

Discuss the co-administration of meperidine and MAO inhibitors.

Meperidine + MAO inhibitors can cause serotonin syndrome S/Sx → Hyperthermia, mental status changes, hyperreflexia, seizures, death MAO inhibitors: phenelzine, isocarboxazid, tranylcypromine

What is the best TEE view for diagnosing myocardial ischemia?

Mid papillary muscle level in short axis

What opioids produce an active metabolite?

Morphine and meperidine

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%

Discuss the pathophysiology of myotonic dystrophy.

Myotonic dystrophy is characterized by a prolonged contracture after a voluntary contraction. This is the result of dysfunctional calcium sequestration by the sarcoplasmic reticulum. Contractions can be so severe that they interfere with ventilation and intubation

What is the relationship between N2O and bone marrow depression?

N2O inhibits methionine synthase and folate metabolism → megaloblastic anemia

Which cerebral receptors are stimulated by nitrous oxide?

N2O produces: -NMDA antagonism -Potassium 2P-channel stimulation *N2O does not stimulate the GABA receptor

What is necrotizing enterocolitis and who is at risk?

NEC is necrosis of the bowel; usually the terminal ilium and proximal colon. -Likely the result of early feeding, impaired absorption by the gut leads to states, bacterial overgrowth, and infection At risk babies -Prematurity (< 32 weeks) -Low birth weight (< 1500 g)

Compare and contrast neuroleptic malignant syndrome with malignant hyperthermia.

NMS is caused by dopamine depletion in the basal ganglia and hypothalamus -Causes → dopamine antagonists -Treatment → bromocriptine, dantroline, ECT

Which opioid antagonist has the longest duration of action?

Naltrexone does not undergo significant first pass metabolism -PO → duration of 24 hours

How do position changes affect the position of the ETT?

Neck position -Neck flexion pushes the ETT towards the carina → increased risk of endobronchial intubation -Neck extension pulls the ETT towards the vocal cords → increased risk of inadvertent extubation Carina position -In the Trendelenburg position, the abdominal contents shift cephalad →this pushes the diaphragm towards the ETT increasing the risk of endobronchial intubation *Remember, the tube goes where the nose goes

Why do neonates desaturate faster than adults?

Neonates have a/an: -Increased oxygen consumption to support metabolic demand -Increased alveolar ventilation to increase oxygen supply -Slightly decreased FRC reflects a reduced oxygen reserve -The net result is that the neonate has an increased ratio of alveolar ventilation relative to the size of its FRC.

Do neuraxial opioids cause sympathectomy, skeletal muscle weakness, and/or changes in proprioception?

Neuraxial opioids do NOT cause: -Sympathetcomy -Skeletal muscle weakness -Changes in proprioception

Discuss the mechanism of action of neuraxial opioids?

Neuraxial opioids inhibit afferent pain transmission in the substantial gelatinosa of the dorsal horn. -Neurotransmission is reduced by: -Decreased cAMP -Decreased Ca+2 conductance (pre-synaptic neuron) -Increased K+ conductance (post-synaptic neuron) -Epidural opioids also diffuse into the systemic circulation, where the blood delivers them them to opioid receptors throughout the body

Is N2O safe in the patient with a traumatic brain injury?

No, it can worsen other injuries such as an undiagnosed pneumothorax

Where is the P6 acupressure point and why is it important?

Non-pharmalogic method of reducing PONV

What is the yearly maximum for radiation exposure? -How does this change if someone is pregnant?

Non-pregnant -Yearly maximum is 5 rem -Eye and thyroid are most susceptible to injury Pregnant -The yearly maximum exposure for the fetus of a pregnant worker is 0.5 rem or 0.05 rem/month -The fetus is most susceptible to injury

Discuss how anesthesia in the lateral decubitus position affects the V/Q relationship.

Nondependent lung -Moves from an area of less compliance to more compliance, ventilation of optimal in this lung Dependent lung -Moves to an area of less compliance -Perfusion is better in this lung *Net effect - Ventilation is better in the nondependent lung, perfusion is better in the dependent lung - this creases a V/Q mismatch and increases the risk of hypoxemia during OLV

Can remifentanil be used for neuraxial anesthesia? -Why or why not?

Nope, it can cause skeletal muscle weakness

Define heat of vaporization.

Number of calories required to vaporize 1 mL of liquid

How do opioids affect thermoregulation?

Opioids reset the hypothalamic temperature set point → decreased core body temperature

Describe the mechanism of action, clinical use, and key side effects of osmotic diuretics.

Osmotic diuretics -Mannitol -Glycerin -Isosorbide MOA -Osmotic diuretics are sugars that undergo filtration but not reabsorption. They inhibit water reabsorption in the proximal tubule as well as the loop of Henle. Water is excreted in excess of electrolytes Clinical uses -Free radical scavenging -Prevention of acute kidney injury (little evidence) -Intracranial hypertension Key side effects -Volume overload in CHF patients -Pulmonary edema -If the blood-brain barrier is disrupted → cerebral edema

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

Other receptors that share a similar pathway -Histamine-1 -Muscarinic-1, 3, 5 -Vasopressin-1

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

Other receptors that share a similar pathway -Histamine-2 -Vasopressin-2 -Dopamine-1 (postsynaptic)

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

Other receptors that share a similar pathway -Muscarinic-2, 4 -Dopamine-2 (presynaptic)

Define the alveolar gas equation

PAO2 = FiO2 x (Pb - PH2O) - (PaCO2/RQ) -Pb = Atmospheric pressure (760 mmHg at sea level) -PH2O = 47 mmHg -RQ = Respiratory quotient = 0.8 Normal = 105.98 mmHg

Compare and contrast the architecture of the SNS and PNS efferent pathways.

PNS -Preganglionic: Long, myelinated, B-fiber - releases Ach -Postganglionic: Short, unmyelinated, C-fiber - releases Ach SNS -Preganglionic: Short, myelinated, B-fiber - releases Ach -Postganglionic: Long, unmyelinated C-fiber, releases NE

Which induction agent is most likely to cause PONV?

PONV is more common with etomidate than with any other induction agent (may be as high as 30-40%)

What are the best tests of hepatic synthetic function? -Which are best for acute injury? Why?

PT -Normal value = 10.9-12.5 seconds -Very sensitive for acute injury Albumin -Normal value = 3.5-5.0 g/dL -Not sensitive for acute injury

What is the formula for pulmonary vascular resistance?

PVR = [(MPAP - PAOP) / CO] x 80 -Normal = 150-250 dynes/sec/cm^5

Define allodynia and give an example.

Pain due to a stimulus that does not normally produce pain -Ex: Fibromyalgia

Define neuralgia and give an example.

Pain localized to a dermatome -Ex: Herpes zoster (shingles)

At sea level, the agent monitor measures the end-tidal sevoflurane as 3%. What is the partial pressure of sevoflurane in the exhaled volume?

Partial pressure = 0.03 x 760 mmHg -Answer = 22.8 mmHg

Which patient populations should not receive a defasiculation dose of a non depolarizing neuromuscular blocker?

Patients with pre-existing skeletal muscle weakness, such as myasthenia gravis

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

Patients with up regulation of extrajunctional receptors are resistant to nondepolarizers, the 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"

Why is bacterial contamination more common with platelets than with RBC's or FFP?

Platelets are stored at room temperature

What is the greatest risk of a supraclavicular block? -Why?

Pneumothorax -Tall and thin patients have a higher risk of this complication -Consider pneumothorax if the patient coughs or complains of chest pain during needle manipulation

Describe the mechanism of action, clinical use, and key side effects of potassium-sparing diuretics.

Potassium-sparing diuretics -Spironlactone -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 potassium-sparing diuretics called aldosterone antagonists. By blocking aldosterone at mineralocorticoid receptors, spironolactone inhibits potassium secretion and sodium reabsorption the collecting ducts. Clinical uses -To reduce K+ loss in a patient receiving a loop or thiazide diuretic -Secondary hyperaldosteronism Key side effects -Hyperkalemia -Metabolic acidosis -Gynecomastia -Libido changes -Nephrolithiasis

How does pregnancy affect gastric pH and volume?

Pregnancy increases gastric volume and decreases gastric pH → due to increased gastrin

What is apoptosis?

Process of programmed cell death. This is the main concern related to anesthesia and children

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%

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 are the key functions of each part of the nephron?

Proximal tubule -Bulk reabsorption of solutes and water Loop of Henle (Desceding) -Countercurrent mechanism -High permeability to H2O Loop of Henle (Ascending) -Countercurrent mechanism -No permeability to H2O Distal tubule -Fine tunes solute concentration (aldosterone and ADH) Collecting duct -Regulates final concentration of urine (aldosterone and ADH)

List 2 conditions commonly associated with pulsus paradoxus.

Pulsus paradoxus → constrictive pericarditis and pericardial tamponade

Describe the pathophysiology and presentation of postdural puncture headache.

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. -The classic presentation includes a fronto-occipital headache, which may be accompanied by nausea, emesis, photophobia, diplopia, and tinnitus. In the upright position, gravity makes the headache worse, while the supine position brings relief.

What is the etiology of opioid induced skeletal muscle rigidity?

Rapid IV administration of potent IV opioids can cause skeletal muscle rigidity (mu receptor). -Historically → woody chest syndrome -No known that the most resistance is at the larynx

Discuss the pathophysiology of renal osteodystrophy.

Renal osteodystrophy is caused by: -Decreased vitamin D production -Secondary hyperparathyroidism An inadequate supply of vitamin D impairs calcium absorption in the GI tract. The body response to hypocalcemia by increasing parathyroid hormone release, this action demineralizes bone to restore the serum Ca+2 concentration. -Net result is a decreased bone density and increased risk of bone fractures

What happens when a nerve repolarizes?

Repolarization is the removal of the positive charges from inside the cell → accomplished by potassium efflux

What is the best indicator of ventilation during neonatal resuscitation?

Resolution of bradycardia is the best indicator of adequate ventilation

How does obesity affect the dosing of nondepolarizing neuromuscular blockers?

Roc/Vec -Induction → LBW -Maintenance → LBW -Cis/Atracurium -Induction → TBW -Maintenance → TBW or LBW

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?

Rocuronium is the only nondepolarizer that can be given via the IM route -If < 1 year = 1 mg/kg -If > 1 year = 1.8 mg/kg

How does cauda equina syndrome present? -What is the treatment?

S/Sx -Bowel and bladder dysfunction, sensory deficits, weakness and/or paralysis Treatment -Supportive

How do transient neurologic symptoms present? -What is the treatment?

S/Sx -Severe back and butt pain that radiates to both legs -It generally develops within 6-36 hours and persists for 1-7 days Treatment -NSAID's, opioid analgesics, and trigger point injections

What is the formula for systemic vascular resistance?

SVR = [(MAP - CVP) / CO] x 80 -Normal = 800 - 1500 dynes/sec/cm^5

Describe the Modified Brooke formula for resuscitation in burn patients.

Same as parkland, but 4 mL LR in first 24 hours is reduced to 2 mL LR

Discuss the use of succinylcholine in the patient with spinal cord injury.

Sch should be avoided 24 hours after injury and should not be used for at least 6 months thereafter

How does sensitivity to LA's change in the elderly?

Sensitivity to LA's increases -Decreased number of myelinated nerves -Decreased diameter of myelinated nerves -Decreased conduction velocity

What is the etiology and treatment of serotonin syndrome?

Serotonin syndrome occurs when there's excess 5-HT activity in the CNS and PNS -SSRI and meperidine, fentanyl, methylene blue -MAOI and meperidine, ephedrine

Describe the short and intermediate term benefits of smoking cessation.

Short term (Does NOT reduce the risk of postoperative pulmonary complications) -SNS stimulating effects dissipate after 20-30 minutes -P50 returns to near normal in 12 hours (CaO2 improves) Long term - Return of normal pulmonary function (6 weeks) -Airway function -Mucociliary clearance -Sputum production -Pulmonary immune function -Hepatic enzyme induction subsides

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)

How does neuraxial anesthesia affect renal and hepatic blood flow?

So long as systemic blood pressure is maintained, hepatic and renal blood flow and function are unchanged

Aside from an epidural blood patch, which regional technique is used to release post-dural puncture headache?

Sphenopalatine block

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 Ventilation -Best = Mapleson A -Worst = Mapleson B Controlled Ventilation -Best = Mapleson D -Worst = Mapleson A

What is the best induction technique for a patient with an anterior mediastinal mass?

Spontaneous ventilation preserves the normal airway, distending the pressure gradient. -This pressure gradient is often abolished during PPV -The sitting position and maintenance of spontaneous ventilation will minimize, but not always prevent, compression of the vital chest structures

What is the treatment for adrenal insufficiency?

Steroid replacement → 15-30 mg cortisol equivalent/day

Discuss how the brachial plexus is susceptible to stretch and compression injury.

Stretch Injury -Occurs because the brachial plexus is anatomically fixed at two location → the cervical vertebrae and the axillary fascia -As a general rule, the risk of stretch injury is highest when he arms are abducted > 90 degrees and/or the head is rotated to one side Compression injury -Usually occurs when the brachial plexus is compressed as it passes between the clavicle and first rib or by an external force (shoulder brace or bean bag)

Rank the neuromuscular blockers according to their likelihood of causing anaphylaxis.

Succinylcholine > atracurium > cisatracurium > rocuronium > vecuronium

How is sugammadex metabolized?

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

What is the mechanism of action of sugammadex?

Sugammadex is a gamma-cyclodextrin made of 8 sugars assembled in a ring. The ring encapsulates the neuromuscular blocker, rendering it inactive and unable to engage with he nicotinic receptor

How do you calculate the law of Laplace for a sphere? -For a cylinder?

Surface tension of a sphere -Tension = (Pressure x Radius) / 2 -Examples: alveolus, cardiac ventricle, saccular aneurysm Surface tension of a cylinder -Tension = (Pressure x Radius) -Examples: blood vessels, aortic aneurysm

Describe the pathophysiology of systemic lupus erythematous.

Systemic lupus erythematous is an autoimmune disease characterized by the proliferation of antinuclear antibodies. SLE affects nearly every organ system, and most of the consequences are the direct result of antibody induced vasculitis and tissue destruction

What TOF ratio correlates with full recovery from neuromuscular blockade?

TOF ration of > 0.9 is achieved at the adductor pollicis

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

What regions of the brain are NOT protected by the blood-brain-barrier?

The BBB is not present at the chemoreceptor trigger zone, posterior pituitary gland, pineal gland, choroid plexus, and parts of the hypothalamus

Discuss the relationship between shoulder arthroscopy, interscalene blockade, and hypotensive bradycardia episodes.

The Bezold-Jarisch reflex is the proposed mechanism for hypotensive bradycardia episodes during shoulder arthroscopy with the inter scalene blockade. These patients are typically in the sitting or semi-upright position. -S/Sx → bradycardia, hypotension, syncope -Venous pooling in the lower extremities reduces venous return. The combined effects of an unloaded ventricle, SNS stimulation, and epinephrine uptake (from the block) results in a profoundly undefiled ventricle that slows its rate to increase diastolic filling time

Explain the Coanda effect and give some examples.

The Coanda effect describes how a jet flow attaches itself to a nearby surface and continues to flow along that surface, even when the surface curves away from the initial jet direction

Which patient populations benefit from a TAP block?

The TAP block targets the nerves of the anterior and lateral abdominal wall -Best suited for abdominal procedures that involve T9-L1 (general, GYN, urologic) -Bilateral TAP blocks are required for a midline incision or laparoscopic surgery

What is the TIPS procedure?

The TIPS procedure bypasses a portion of the hepatic circulation by shunting blood 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

Why does RV increase in the elderly? -What are the consequences of this?

The aged lung has a reduced elastic recoil, which causes it to become over filled with gas → increased RV and subsequent increased FRC -CC surpass FRC at 45 years in the supine position and 65 years when standing -When CC > FRC the small airways collapse during tidal breathing

Define specific heat.

The amount of heat required to increase the temperature of 1 gram of a substance by 1 degree C