Anesthesia Clinical Preparation
The hematocrit is usually ________ the hemoglobin value
3 times
Epidural catheter insertion beyond needle tip should be ______
3-5cm
All epidural solutions should be injected in increments of ________ every _________ and titrated to desired anesthetic level
3-5ml 3 minutes
The tip of the ETT can move an average of ________ toward the carina when the neck is moved from full extension to full flexion
3.8 cm (up to 6 cm)
During a Bier block, most adults, _______ of ____________ is sufficient.
30-50ml 0.5% (3ml/kg)
Oxygen flush valve required by standard to deliver...?
35 to 75 L/min
How long can you use jet ventilation on someone?
45 minutes
Dose of Sugammadex for 1-2 PTC after 5 seconds tetanic stimulation?
4mg/kg
ETT placement in the carina?
5 cm (+-2cm)
A circle system with FGF above minute ventilation greater than ____ to _____ is associated with little if any reliance on absobent granules...? What happens to exhaled CO2?
5 to 8 L/min exhaled CO2 is rapidly diluted and sent to the scavenger
Lidocaine IV doses should be decreased ____ in the following individuals to avoid CNS toxicity...
50% ->70yrs -liver disease
MAC is decreased by ____% for each decade of life
6% (or 6.7%)
LMA intracuff pressure should not exceed?
60 cm H2O (if overinflated can cause posterior cricoarytenoid muscle fatigue)
TBW questions rule
60/40/20 (15/5)
wavelength of deoxygenated hemoglobin (red light) wavelength of oxygenated hemoglobin (infared light)
660 nm 940 nm
PONV incidence in laparoscopic surgery is as high as _____ and associated with wound dehiscence, aspiration, hospital admission. _____ for susceptible patients combined with _____ has proven to be effective
72% TIVA antiemetics
Dose of Sugammadex for immediate reversal of rocuronium-induced NMB?
8-16mg/kg (or profound block)
What is the time to recovery to 90% muscle strength following 1mg/kg of succinylcholine?
9 to 13 minutes
Cervical, thoracic, midlumbar epidural space area
Cervical - 1.5-2mm Thoracic - 3-5mm Midlumbar - 5-6mm
LR is contraindicated in patients with? Why?
traumatic brain injury orother neurovascular insultsbecause LR is mildly hypotonic and may causetransient serum hypo-osmolality and associated cerebral edema
Never deflate the tourniquet less than ________ after injection, even if surgery is shorter than that time period
20 minutes
From a clinical standpoint patient usually require anesthetic concentrations that exceed the MAC by...
20-30% (1.2-1.3 times MAC)
What is the most common spinal needle used?
25g Whitacre
Assuming a service pressure of 2000psi in an e cylinder, your pipeline O2 fails. When you turn on your back up tank you notice it is half full. If you hand ventilate your patient, without using O2 flush valve, what FGF setting of 100% oxygen will get you exactly 165 minutes of supply?
2L/min Capacity L/service pressure psi = contents remaining L/gauge pressure psi
A patient can be safely discharged home from the PACU if they do not experience any of the following symptoms within _____ of aspiration, symptoms include:
2hrs -new cough or wheeze -x-ray evidence of pulm injury -SpO2 dec =>10% of preop values -A-a gradient =>300mmHg
In the spontaneously ventilating patient, we assume that dead space (Vd) is _______ in a 70kg patient, therefore __________
2mL/kg or 150mL Vd/Vt = 150mL / 450mL = 0.33
Dose of sugammadex for reversal of rocuronium-induced NMB with TOF count 2?
2mg/kg
Degradation of sevoflurane by soda lime results in the production of : A. Compound A B. Compound B C. Compound C D. Compound D
A. degraded most by soda lime.
What blood type is the universal donor for plasma?
AB positive (donor plasma does not contain plasma antibodies)
List the absolute and relative contraindications of peripheral nerve blocks:
Absolute -patient refusal -infection at inj site -coagulopathy or bleeding diathesis Relative -uncooperative/psychiatric -preexisting neurologic disease
Where does the spinal cord end? Adult Infant
Adult - spinal cord ends L1/L2, dural sac ends at S2 Infant - spinal cord ends L3, dural sac ends at S3
What are the basal O2 requirements:
Adult: 4 mL/kg/min (250 mL/min)
Advantages and disadvantages of extubation of an awake patient
Advantages 1. return of airway reflexes 2. decreased risk of aspiration 3. airway reflex return 4. spontaneous ventilation Disadvantages 1. inc CV stimulation 2. inc cough & straining
CO formula (2)
CO = HR x SV or HR x (EDV - ESV) divide by BSA for CI
Cardiovascular effects of inhalation anesthetics (CO, SVR, MAP, HR) Isoflurane Desflurane Sevoflurane N20
CO, SVR, MAP, HR Isoflurane: dec, dec, dec, inc Desflurane: -, dec, dec, inc Sevoflurane: -, dec, dec, - N20: dec, inc, -, inc
what is the crisis management algorithm
COVER ABCD C- circulation, color, capnography O- oxygen V- ventilation, vaporizer E- ETT R- review monitors & equipment A-airway B-breathing C-circulation D- drugs (evaluating effects)
CPP formula
CPP = DBP - LVEDP (preload) -normal conditions LVEDP (10mmHg) sig less than DBP (80mmHg) -Major determinant of CPP is DBP
Formula to calculate how long oxygen cylinder will last
Capacity L/service pressure psi = contents remaining L/gauge pressure psi example, if the oxygen flow is 2 L/min, and the cylinder's oxygen gauge pressure is 500 psi, how long will the cylinder last? we know that the service pressure is 1900 psi and that the capacity is 660 L. Substituting these values into the previous relationship, we obtain the following: Because 2 L of oxygen flow each minute, the cylinder will last approximately 87 minutes (174 L ÷ 2 L/min). This type of calculation is not applicable to compressed gases stored as liquids (nitrous oxide or carbon dioxide)
Cauda Equina Syndrome cause, factors, s/sx, tx
Cause - neurotoxicity result of high conc of LA Factors that increase - 5% lidocaine & spinal micro catheters S/Sx - B&B dysfunction, sensory deficits, weakness, paralysis Tx - supportive
Transient Neurologic Symptoms (TNS) cause, factors, s/sx, tx
Cause - pt position, stretching sciatic nerve, myofascial strain, muscle spasm Factors that increase risk - lidocaine, lithotomy position, ambulatory surgery, knee arthroscopy S/Sx - severe back and butt pain radiates to legs, develops 6-36hrs, last 1-7 days Tx - NSAIDs, opioids, trigger point injections
What are the two classifications and types of spinal needles?
Cutting tip Quincke Pitkin Non-Cutting tip Sprotte Whitacre Pencan Greene
Decreased pulmonary changes in the elderly include:
Decreased -pulm elasticity -arterial O2 tension -muscle strength -cough effectiveness -breathing capacity -small airway diameter -resp center sensitivity -chest wall compliance -alveolar surface area
oxyhemoglobin dissociation curve factors causing right shift
Decreased affinity for O2 (right=release) -increased temperature -increased 2,3-DPG -increased CO2, H+ -decreased pH
The volatile agent of choice for patients with emphysema or sleep apnea is?
Desflurane
Which inhalation agent is considered a respiratory irritant when used for mask induction in high concentrations?
Desflurane (concentrations >6%) (not used to induce anesthesia in pediatric and adult patients) -pungent
DISS
Diameter Index Safety System - prevent misconnections, cross connection difficult but not impossible
Respiratory effects associated with pneumoperitoneum: Diaphragm shifts cephalad Insufflation of CO2
Diaphragm shifts cephalad Decreased - FVC, FEV1, FRC, VC Increased - PIP Insufflation of CO2 Decreased - pulm compliance Increased - PaCO2 & ETCO2 (acidosis), intrathoracic pressure
Which bedside subjective monitoring technique of neuromuscular blockade using the peripheral nerve stimulator is thought to offer the greatest sensitivity to recovery from blockade?
Double burst stimulation
EF formula
EF = (SV/EDV) x 100 EF 60-70%, <40% sig LV dysfunction
Estimated fluid deficit
EFD = maintenance fluid requirement x fasting hours
Which beta blocker is the best choice for asthma patients?
Esmolol (short half-life & B1 selectivity)
Which sympothalytic agent is useful in treating adverse systemic bp and hr increases intraoperatively in response to noxious stimulation as during tracheal intubation?
Esmolol 150mg IV administered 2 minutes before direct laryngoscopy and tracheal intubation
What do fail-safe systems do?
Halt the supply of all other gases in the event of oxygen supply pressure failure
Pulmonary Reflexes/Receptors
Hering-Breur -stretch receptors in smooth m. of airways -dec rr Irritant receptors -located in epithelium -initiate cough reflex to mechanical/chemical stimuli J receptors -respond to hypoxic conditions that jam pulm vasculature (PE/CHF) -inc rr Bronchial c-fibers -pain (slow throbbing pain) Paradoxical reflex of head -causes newborn take 1st breath
The most serious risk of Bier block is...
LAST d/t cuff failure
The ________ _________, also termed the laryngospasm notch, can be applied while performing a vigorous jaw thrust using bilateral firm pressure on the styloid process behind the posterior ramus of the mandible and anterior to the mastoid process.
Larson maneuver (anecdotal evidence for breaking laryngospasms)
Causes of decreased compliance
Less change in volume at equal pressures -tissue fibrosis -alveolar edema -atelectasis -pulmonary hypertension -low surfactant -high lung volumes
_________ 1-3 minutes before extubation suppresses airway reflexes
Lidocaine 1-1.5mg/kg
What is LAST?
Local Anesthetic Systemic Toxicity -due to excess plasma concentration of LA -accidental direct intravascular injection of LA during peripheral nerve block or epidural
Ventilation protocol used in the ARDS network study:
Mode: volume AC VT: =<6mL/kg PBW Plateau pressure: =<30cmH2O Frequency: 6-35 breaths/min, titrate pH 7.3-7.45 I:E ratio: 1:1 to 1:3 Oxygenation goal: PaO2 55-80mmHg or SpO2 88-95% PEEP: 5-24 Weaning: PS, FiO2/PEEP =< 0.4/8
Damage to the liver results from what acetaminophen metabolite?
N-acetyl-p-benzoquinoneimine (NAPQI)
Which inhalation agent antogonizes NMDA receptors and may produce a significantly lower risk of chronic pain after surgery?
N20
Which inhalation agent increases the risk of PONV?
N20
Which inhalation agent is not a triggering agent for MH?
N20
The most common location for a leak to occur in the low pressure system is...
-internal leak in the vaporizer -leak can only be detected when vaporizer is turned on
Which PNBs have the highest incidence of phrenic nerve blockade?
-interscalene -supraclavicular
What is ED50?
-is the median effective dose at which 50% of a population responds as desired -often used for comparing potency of drugs within a class
How should an open scavenging interface be set?
-keep indicator float between lines (audible suction means working) -closed interfact you hear a hiss sound from waste gas escaping into room -open interface safe for pt d/t no chance of excess pos or neg pressure transmit to breathing circuity, but potential for waste gas exposure
Anesthetic management for robotic procedures:
-keep paralyzed -OG/NG to decompress stomach -limit fluids (facial edema) -pulse ox placement (no pressure) -caution prolonged press back of scalp
Surgical risk factors which increase risk of PONV include:
-long surgical procedures -gynecologic surgery -laparoscopic surgery -ENT surgery -breast surgery -plastic surgery -orthopedic surgery
What factors decrease dead space?
-longer inspiration -ETT (50%), LMA, tracheostomy -neck flexion, head down position -supine
Preoperative management for patients with obstructive lung disease
-look for tests results: PFT, ABG, CBC, CXR -consider PNB (caution with ISB) -No H2 blockers: unopposed H1-mediated bronchoconstriction
Spinal and Epidural differences Spinal
-low dose (1.5-2ml) -fast onset (5min) -cause sig nm block -single dose only -only given at specific point along backbone to prevent damage to spinal cord
OSA characteristics
-men>woman -apnea/hypopnea during sleep, obstruction (pharyngeal collapse) -definitive diagnosis: polysomnography (abn resp events/hr) (AHI>15-30) -assoc comorb: htn, pulm htn, ischemic heart disease, chf, obesity, diabetes
Elderly age-related CV changes include:
-myocardial hypertrophy (failure to maintain preload) -myocardial stiffening (diastolic dysfunction) -reduced LV relaxation (diastolic dysfunction) -reduced β receptor responsiveness (hypotension, Frank Starling) -conduction abnormalities (severe brady with potent opioids, dec CO) -stiff arteries (labile BP) -stiff veins (changes in blood volume)
Features of GlideScope Video Laryngoscope
-no sniffing position required -distal 60 degree anterior bend, 18mm wide -antifog system heats lens around camera
How are TLC, FRC, FEV1/FVC, and FVC altered in obstructive lung disease?
-normal TLC, FRC, FVC -decreased FEV1, FEV1/FVC
Oxygen capacity (content): max O2 combined with Hb:
-o2 content is measure of o2 present in 1 dL of blood -CaO2 = (SaO2 x Hb x 1.34) + (0.003 x PaO2)
Intraoperative bronchospasm causes:
-obstructed ETT (kinking, biting, secretions, overinflated cuff) -light anesthesia (deepen VA, IV) -endobronchial intubation -PE, pulm edema, pneumothorax, aspiration
Airway anatomic difference in the elderly include:
-obstruction: d/t dec laryngeal & pharyngeal sup -endentulous: poor mask ventilation -arthritis: dec ROM -dec protective laryngeal reflexes-inc risk of asp
Epidural blood patch procedure
-obtain consent -patent IV (AC) -prep & drape back -insertion site at or below level of lowest initial needle insertion -draw 20ml blood from IV -after LOR, inject blood into space -inj proceeds until pt senses pressure in back, buttocks or legs (12-15ml) -pt to remain supine 30-60min after procedure
Arterial line dampening
-occurs d/t air bubbles, kinks, distensible tubing, low flush bag, clots -severe hypotension if all else ruled out -under estimates SBP, over est DBP
What factors increase dead space?
-old age, larger habitus -facemask, heat & moisture exchanger, PPV -GA, anticholinergics (bronchodilator) -neck extension -dec CO, pulm bf, COPD, PE, emphysema, smoking -sitting position
Recent device check recommended
-pacemaker interrogated every 12 months -ICD every 6 months
Neuraxial anesthesia absolute contraindications
-patient refusal -inf at site of injection -coagulopathy or bleeding do -severe hypovolemia -inc intracranial pressure -severe AS & MR
Pulmonary Shunt
-perfusion without ventilation -physiologic - venous admixture, total amount of unoxygenated blood returned to arterial system -anatomic - normally 2-5% of CO, venous blood bypasses resp exchange area & returned to left side of heart
List the complications from interscalene block
-phrenic nerve block (ipsilateral diaphragmatic hemiparesis) -subarachnoid/epidural injection -IV injection -pneumothorax (rare)
List potential complications of supraclavicular block (which is most serious?)
-pneumothorax (most serious, 6% risk) -Horner's syndrome (miosis, ptosis, anhidrosis) = Stellate ganglion block -subclavian artery puncture (hematoma)
The patient's breaths are stacking up in the chest and the circuit pressure is sustained at a high level. What can you do in the few seconds before the patient is injured?
-possible obstruction of scavenger or failure of ven relief valve -d/c gas collection tubing from back of APL valve if poss -or turn off vacuum at scavenger interface -if cannot d/c, vent mannually with breathing circuit, if unable to vent, use ambu bag and start TIVA
What are the major respiratory complications that can occur from placing the patient in Trendelenburg position to facilitate visualization during laparoscopy?
-pulm compliance dec about 50% -peak plateau pressures inc 50% -require 20-30% inc in minute ventilation needed to maintain baseline CO2 levels and prevent resp acidosis (inc Vt rather than RR, PC > VC caution when insufflation released)
Vancomycin (glycopeptide) side effects include:
-rapid adm <30min, profound hypotension & cardiac arrest -histamine release -red man syndrome -allergic reaction -arterial hypoxemia (dec SpO2) -ototoxicity -nephrotoxcity
What are the most commonly used methods of treating intraoperative hypotension in the chronically hypertensive patient?
-reduce amount of VA -ensure adequate volume expansion (fluids) -phenylephrine 25-50mcg or ephedrine
Medical Air is ___% Nitrogen, ___% Oxygen, is dry, and contains a minimum number of impurities.
Nitrogen 78%, Oxygen 21%,
What blood type is the universal acceptor for plasma?
O negative (patient already has both plasma antibodies present)
Gas cylinder pin position of O2 N2O Air
O2 2-5 N2O 3-5 Air 1-5
Gas cylinder capacity (L)
O2 660L (white) N2O 1590L (blue) Air 625L (blk white)
Hemodynamics is all about _______
OHM's law ∆P = Flow x Resistance
Average estimated blood volume Obese Female Male Muscular
Obese - 60 ml/kg Female - 65 ml/kg Male - 70 ml/kg Muscular 75 ml/kg
_________, _________, and __________ administered before induction of general anesthesia are equally effective in decreasing the incidence of PONV.
Ondansetron 4mg, dexamethasone 4mg, and droperidol 1.25mg
Naloxone doses, half-life, se
Opiate overdose •0.2-4mg IV q2-3min PRN (max 10mg) then may infuse at 0.4mg/hr and titrate to effect Reversal of opiate respiratory depression •0.04-0.4mg doses IV titrated q2-3min •infusion load of 5mcg/kg followed by 2.5-160mcg/kg/hr Treatment of opiate-induced pruritus •0.25mcg/kg/hr half-life: 64 min SE: n/v, htn, arrhythmias, pulm edema, sudden pain
Clinically how can preload be measured?
PCWP and PADP
PT, aPTT, INR normal range
PT: 12-14s aPTT: 25-35s INR: <1.1 (2-3 on coumadin)
PVR formula
PVR = (MPAP-PCWP)/CO x 80 <200 dynes/sec/cm5
What is a useful indicator in PE, with high sensitivity and specificity?
PetCO2 (difference between PaCO2 & EtCO2) -low d/t high V/Q ratio in embolized region -accurate & immediate indicator of status of pulm gas exchange
The physiologic basis of the cardiac action potential: Phase 0, 1, 2, 3, 4
Phase 0 represents rapid depolarization as a result of opening of Na+ channels and closing of K+ channels. Phase 1 is the period of initial repolarization that results from closure of Na+and opening of K+ channels. Phase 2 is the plateau phase that results from the sustained Ca++ current that began with the initial depolarization. Phase 3 is repolarization due to opening of K+ and closure of Ca++ channels. Phase 4 is the resting potential during which time K+ channels are open and Na+ and Ca++ channels are closed.
PISS
Pin Index Safety System unique arrangement of holes that correspond to its intended contents, hole mate with pins in the yoke which is point where cylinders are attached to gas machine, prevents misconnections
Lidocaine MOA
Produces analgesia by suppressing the activity of sodium channels in neurons that respond to noxious stimuli, thereby preventing nerve conduction and pain transmission
Neostigmine works by
Produces reversible inhibition of ach-esterase. Permits accumulation of ach at the nmj. Improves chances of 2 ach molecules to displace the muscle relaxant by binding the alpha subunit of the nicotinic receptor, thus reversingparalysis
What are the recommended dosing for the following drugs? Propofol Etomidate Opioids Midazolam NDMRS Depolarizing MR
Propofol: 1-1.5mg/kg by 50% Etomidate: by 50% Opioids: by 50% Midazolam: by 75% NDMRS: slower onset, no change in dose Depolarizing MR: slower onset, no change in dose
Poisuille's Law
R= (8ηl)/(πr^4 ) R: resistance to laminar flow η: viscosity r: uniform radius of tube l: length of tube
RACE PASS
RACE- Rescue, Alarm,Confine, Extinguish PASS-Pull, Aim, Squeeze, Sweep
Which medications are used to treat MH in adults and children?
Raynodex and Dantrolene (Raynodex less volume, prep time, req dose of mannitol)
What are the hemodynamic changes associated with the following positions? Reverse Trendelenburg Trendelenburg Steep Trendelenburg
Reverse Trendelenburg - dec VR, CO, ABP, inc FRC Trendelenburg - dec VR, CO Steep Trendelenburg - dec VR from head = inc ICP & IAOP, venous engorgement of face and neck
Factors that can affect induction rate: Slower Induction
Slower Induction High blood gas solubility High cardiac output Low minute ventilation Low fresh gas flow rates Low concentrations Ventilation perfusion deficits Hypothermia
What is FA/FI ratio?
Tells you how fast anesthetics go into the lungs (fraction of alveoli/fraction inspired)
Minimum alveolar concentration awake (MAC awake)
The MAC suppressing appropriate response to commands in 50% of patients; memory is usually lost at MAC-awake; approximately 0.3-0.5 MAC
Minimum alveolar concentration—block adrenergic responses (MAC-BAR)
The alveolar concentration of anesthetic that blunts the autonomic response to noxious stimuli; approximately 1.6-2.0 MAC
What is the train of four ratio?
Train-of-Four Ratio 3 twitches = 75 - 80% Blockade 2 Twitches = 80 - 85% Blockade 1 Twitch = 90 - 95% Blockade 0 Twitch = 100% Blockade
Withdrawal hypersensitivity enhanced activity reflects an increase in the number of β-adrenergic receptors (upregulation) during chronic therapy with β-adrenergic antagonists. T/F
True
What are the three major factors that promote the formation of venous thrombi?
Virchow's triad 1. stasis of blood flow 2. venous injury 3. hypercoagulable states
Ventilator settings and extubation for patients with obstructive respiratory pathology
Vt: 10-15ml/kg RR 6-10 I:E ratio: 1-2.5/3 (prevent air trapping) PEEP: when indicated to maintain oxygenation/CO2 elimination (caution may rupture bullae) Extubation: consider deep extubation, lidocaine bolus
When does N2O cylinder pressure begin to fall below 745psi?
When cylinder is more than 3/4 empty, should be changed if pressure <745psi
When does the tidal volume of gas pass through the CO2 absorber on a circle circuit?
When does the tidal volume of gas pass through the CO2 absorber on a circle circuit?
Predictors of difficult mask ventilation include: (Select 3) a. presence of a beard b. age 50 years c. edentulousness d. BMI 25 kg/m2 e. Mallampati II f. history of snoring
a. c. f. BONES beards, obese, no teeth, elderly, snoring
Which characteristics predict difficulty with laryngoscopy? (Select 3) a. long upper incisors b. prognathism c. long neck d. mandibular protrusion test class three e. Cormack-Lehane class four f. arched palate
a. d. f.
Which nerve innervates the region where the tip of the macintosh blade should be placed during laryngoscopy? a. glossopharyngeal nerve b. recurrent laryngeal nerve c. superior laryngeal nerve d. trigeminal
a. during laryngoscopy with the Mac blade, the tip of the blade is placed in the vallecula
Which nerve innervates the following structures? a. anterior tongue b. posterior tongue c. soft palate d. oropharynx e. vallecula f. anterior epiglottis g. posterior epiglottis h. vocal cords: i. trachea
a. anterior tongue = mandibular branch of trigeminal nerve b. posterior tongue = glossopharyngeal (IX) c. soft palate = glossopharyngeal (IX) d. oropharynx = glossopharyngeal (IX) e. vallecula = glossopharyngeal (IX) f. anterior epiglottis = glossopharyngeal (IX) g. posterior epiglottis = SLN internal branch (X) h. vocal cords = SLN internal branch (X), RLN (X) i. trachea = RLN (X)
All of the following are landmarks for Larson's manuever except: a. mandibular body b. mastoid process c. ramus of mandible d. skull base
a. mandibular body
What is the action of the intrinsic muscles listed? a. thyroarytenoid b. posterior cricoarytenoid c. cricothyroid d. lateral cricoarytenoid
a. thyroarytenoid = shortens vc b. posterior cricoarytenoid = elongates vc c. cricothyroid = abducts vc d. lateral cricoarytenoid = adducts vc
What is barbotage?
aspiration of the injected volume back into the syringe followed by reinjection twice, with 0.5ml increase in each aspirated volume
What happens when you put a magnet over a pacemaker?
asynchronous mode asynchronous delivers stimuli at a fixed rate, independent of any atrial or ventricular activity; this type is now rarely used except to initiate or terminate some tachycardias -useful when using monopolar cautery -risk of R on T phen, inefficiency -magnet rate (85-100bpm)
Opioids ______ MAC of inhaled anesthetics
decrease
What are the effects of volatile anesthetics on cerebral metabolic rate of O2 consumption (CMRO2) and cerebral blood flow (CBF)?
decrease CMRO2 in a dose-dependent manner increase CBF in dose-dependent manner -uncoupling
What is midazolam's MOA in PONV?
decrease synthesis and release of dopamine and serotonin within the CRTZ
Intravenous regional anesthesia, double tourniquet alternates inflation to _____________, ____________ limits the duration of surgical anesthesia
decrease tourniquet pain tourniquet pain
Increased PaCO2 and decreased PaO2 and arterial pH stimulate the arterial (peripheral) chemoreceptors, with ________ responding first Location:
decreased PaO2 -carotid bodies - found at bifurcation of common carotid, responds PaO2 < 50mmHg -Aortic - via CN X, not important
What is baricity? Types?
density of a LA solution relative to the CSF -hyperbaric LA: falls/sink, more dense (dextrose, prilocaine in h2o) -isobaric LA: remains suspended, equal (saline) -hypobaric LA: Rises, less dense (h2o)
Which anesthetic agent exhibits the fastest clinical recovery?
desflurane
What is the preferred site for determining the level of neuromuscular blockade?
contraction of the adductor muscle of the thumb via stimulation of the ulnar nerve
Soluble drugs stay in the blood in _________ proportion than less soluble agents; therefore, _____ of the drug is released to the tissues during the early, rapid-uptake phase of induction
greater, less (Isoflurane 1.4:1)
What is the drug of choice in the treatment of postoperative delirium?
haldol
Fentanyl does not cause _______ release like morphine
histamine
In case of low pressure loss or cross connection of n2o and o2 you must disconnect the pipeline supply from the wall because?
if the problem is cross connection the pipeline gas will continue to flow. Pipeline pressure is 50psi and cylinder regulator set at 45psi, higher pressure pipeline will flow. Lower pressure is intentionally set on cylinder regulator so that flow proceeds from higher pressure pipeline source if cylinder is inadvertently left open after a machine check
Pulmonary emboli originate from deep vein thrombosis of the __________ vessels in approximately ____ of patients
iliofemoral 90% (other sites: pelvic, renal, hepatic, axillary veins, & RA)
What happens when a local anesthetic is injected into infected tissue?
increases the ionized fraction of drug, poor quality of local anesthesia
Where is the CO2 absorbant locating?
inspiratory limb of the delivery division
Sodium nitroprusside (SNP) is a potent direct-acting, nonselective peripheral vasodilator that causes relaxation of arterial and venous vascular smooth muscle. It's MOA is...
interacts with oxyhemoglobin, dissociating immediately and forming methemoglobin while releasing cyanide and NO that is responsible for the direct vasodilating effect of SNP
Fentanyl - intrathecal, epidural, epidural infusion dosing
intrathecal - 10-20mcg epidural - 50-100mcg epidural infusion - 25-100mcg/hr
Systole is composed of...
isovolumetric contraction, rapid ejection, & reduced ejection
Name the coverings of the heart.
parietal pericardium serous layer of pericardium (parietal & visceral)
The oil/gas solubility coefficient is an indicator of ________. A high solubility coefficient reflects high ______solubility
potency, lipid (Higher coeff, the more potent the agent)
The principal contraindication to administration of β-adrenergic antagonists is
preexisting AV block or cardiac failure not caused by tachycardia
A reduction in which of the following is the primary mechanism for hypotension after a T4 spinal anesthetic?
preload (sympathectomy)
When the patient resides on the lower portion of the Starling curve (slope) they are considered to be
preload dependent
What is the purpose of applying cricoid pressure and in what situation is it used for?
prevent regurgitation and possible aspiration of stomach contents rapid sequence induction for general anesthesia
Sugammadex, used in appropriate doses, is capable of reversing any depth of neuromuscular blockade (profound or shallow) induced by __________or ________to a TOF ratio of 0.9 within ___ minutes
rocuronium vecuronium 3
What drugs can enter the central nervous system and produce central anticholinergic syndrome?
scopolamine and atropine 0.6mg IV
Morphine adult dose sedation/analgesia pca intrathecal epidural
sedation/analgesia = 2-20mg q2-4h IV, IM, SC pca = bolus 1-4mg q6-20min, basal 0-1mg/hr intrathecal = 0.1-0.5mg epidural = bolus 2-6mg q8-24h, infusion 0.2-1mg/h
Flumazenil should be avoided in patients with?
seizure history or tricyclic antidepressant overdose
Because the elderly have a _______ intravenous time, the propofol induction dose should be _________
slower decreased by 50%
The higher the coefficient, the ________ the anesthetic; conversely, the lower the coefficient, the _______ the anesthetic
slower faster
The elderly have a ________ emergence time
slower (d/t lower CO)
The more soluble the volatile agent, the ________ the brain and spinal cord uptake, and therefore _________ anesthesia is achieved
slower, slower
Increased IAP displaces the diaphragm in a cephalad direction, which...
-reduces functional residual capacity (FRC) -predisposes to V / Q mismatching -also displaces carina can cause mainstem intubation
Revised Cardiac Risk Index
(1) Ischemic heart disease (MI, + stress test, nitro use, q waves, past PCI/CABG) (2) Congestive heart failure (3) Cerebral vascular disease (4) High-risk surgery (aortic/vascular) (5) DM with or without insulin tx (6) Preoperative creatinine >2 mg/dL ****1 point for each; each increment in points increases risk for post-op myocardial MI
Components of the high pressure system
(1) hanger yoke, (2) yoke block with check valves, (3) cylinder pressure gauge, and (4) cylinder pressure regulators
Signs and symptoms of endobronchial intubation include:
(1) increased peak inspiratory pressures (2) asymmetrical chest expansion (3) unilateral breath sounds; and (4) hypoxemia
Components of the intermediate-pressure system
(1) pipeline inlets, (2) check valves, (3) pressure gauges, (4) ventilator power inlet, (5) oxygen pressure-failure devices, (6) flowmeter valve, (7) oxygen second-stage regulator (if present), (8) flush valve
The fluid of choice for replacing blood loss is...?
- 1st choice Lactated ringer (LR) 3:1 - 2nd choice Normal saline (risk of hyperchloremic acidosis)
Massive transfusion protocol
- > 10 units PRBCs in 24 hrs - > 4 units in one hour and ongoing instability or hemorrhage - loss of one blood volume in 70kg pt.
Oxygen bound to hemoglobin formula
-(1.34 x Hgb x SaO2) -each gram hgb carry 1.39mL of o2, hgb usually has small amt of meth/carboxyhgb, so may see 1.34/1.32
Oxygen dissolved in the plasma formula
-(PaO2 x 0.003) -dissolved o2 measured by PaO2 -used to determine gas exchange in lungs & not measure of o2 content in blood
MAP equation (2)
-(SBP + 2DBP)/3 -(CO x SVR)/80
Intraoperative bronchospasm treatment:
-100% FiO2 -beta-agonist -epinephrine 1mcg/kg IV -hydrocortisone 2-4mg/kg IV -lidocaine -aminophylline
When performing a pneumoperitoneum, the abdomen is usually inflated to what maximum pressure? Normal pressure range?
-15mmHg -range 12-15mmHg
epidural test dose
-3ml of 1.5% lido w/ epi 1:200,000 (5mcg/ml) -1.5% lidocaine = 15mg/ml (200,000/1,000,000=5mcg epi/ml)
If your fresh gas flow is 4 L/min, what volume is passing through the scavenger each minute?
-4L/min are exiting -if not barotrauma will result if same amount is not leaving as is entering
Intraoperatively, the ideal degree of paralysis necessary for any procedure with sufficient anesthetic depth is...?
-85% to 95% -correlates with 1 to 2 twitch
bier block technique
-August Bier 1908 -short procedures <60min -PIV 22g in operative hand -white padding, double tourniquet on proximal arm -supine, raise arm straight up for exsanguination -arm raised, wrap Esmarch elastic bandage from fingertips to tourniquet -inflate proximal tourniquet to 250mmHg or 100 above SBP and remove Esmarch -place on table, slowly inj the LA, if pt feels discomfort from tourniquet, inflate distal cuff, deflate proximal cuff
Recommendation for replacement of blood loss
-Crystalloid 3:1 (3 mL for every 1 mL EBL -Colloid or Blood 1:1 (1 mL for every 1 mL EBL)
Characteristics of a non-depolarizing neuromuscular blocker include:
-Decrease in twitch tension -Fade during repetitive stimulation (train of four or tetanic) -Post-tetanic potentiation
What negative cardiac effects may be seen with insufflation of the abdomen?
-Decrease venous return and stroke volume -Also see inc MAP, SVR (htn), and HR d/t release of vasopressin, renin, NE, cortisol, aldosterone -CO may be reduced
Which factors decrease FA/FI = Slower onset (curved pushed down):
-Decreased wash in Low FGF Low alveolar ventilation High FRC High time constant High anatomic dead space -Increased uptake High solubility High CO High Pa-Pv difference
ED95
-Effective dose where 95% of patients experience a therapeutic effect
Pulmonary edema anesthetic management from APEX
-FRC reduced, rapid desat -minimize barotrauma -small TV 6-8ml/kg IBW, inc RR 14-18 breaths/min -keep PIP <30 cmH2O -long inspiratory time (I:E ratio 1:1)
What is fade?
-Fade is the inability to sustain a response to repetitive nerve stimulation and is seen in several of the clinically used monitoring tests -Sign of drug-induced muscle paralysis
What is the best way to preoxygenate?
-Fresh gas flow 4-6 L/min -APL valve open fully -Ensure a tight mask fit -May use 3-5 minutes of tidal breathing, or 4 to 8 vital capacity breaths
When should you activate oxygen flush valve if necessary?
-If flushing is necessary for filling the ventilator bellows, it should be done in short pulses, during the expiratory phase -not during inspiratory phase, the ventilator relief valve closes preventing gas from exiting to scavenger
How does the ETCO2 change (↑or ↓) during laparoscopy?
-Increases PaCO2 caused by CO2 absorption by peritoneal serosa d/t increased IAP (respiratory acidosis, not metabolic). Treat by increasing minute ventilation. -Increase in ETCO2 (underestimates arterial by 5-10mmHg)
Pretreatment
-Ischemic HD: Fentanyl 3-5 mcg/kg -Increase ICP: Fentanyl 3-5 mcg/kg +/- Lidocaine 1.5mg/kg -Reactive Airway Disease: Lidocaine 1.5mg/kg
Propofol contraindications
-Known hypersensitivity or disorder of lipid metabolism -Sulfite sensitivity (common asthma pts)
Complications of PNBs include:
-LAST -direct nerve injuries -vascular injury/hematoma -infection
Factors that increase incidence of PDPH
-Large, non-pencil point needle -cutting needle bevel direction -multiple punctures -female -age (<40)
List of lipophilic and hydrophilic opioids
-Lipophilic: sufentanil, fentanyl -Hydrophilic: meperidine, hydromorphone, morphine
Characteristics of a depolarizing neuromuscular blocker include:
-Muscle fasciculations during onset -Decrease in twitch tension -No fade during repetitive stimulation (train of four or tetanic) -No post-tetanic potentiation
Proportioning Systems (Hypoxic Guard)
-N2O-oxygen proportioning to prevent hypoxic mixture -N2O-oxygen ration of no more than 3 to 1
Aspiration pneumonitis preoperative management
-NPO guidelines -metoclopramide, histamine blockers (famotidine, ranitidine), anticholinergics, antacids, PPI, antiemetics -goal raise gastric pH, dec gastric volume, reduce risk emesis -antacids onset 15min, 1-3hrs DOA, H2 blockers give 45-60 min before surgery -cricoid pressure
Platelet count
-Normal range - 150,000-350,000 -Thrombocytopenic <100,000 surgical risk <50,000 (surgical pts need transfusion if microvascular bleed) -spontaneous bleeding <20,000
Side effects of Aminoglycosides include:
-Ototoxicity -Nephrotoxicity -Skeletal muscle weakness
What are the physiologic pulmonary effects and adverse outcomes of acute pain?
-Physiologic effects - Dec VC, TV, TLC, muscle spasms, ability to cough/deep breathe -Adverse outcome - V/Q mismatch, atelectasis, pna, hypoventilation, hypoxia, hypercarbia
What are the physiologic CV effects and adverse outcomes of acute pain?
-Physiologic effects - Inc HR, PVR, ABP, myocardial contraction, myocardial work -Adverse outcome - dysrhythmias, angina, myocardial ischemia, myocardial infarction
What is the purpose of an oxygen flush valve?
-Proceeds directly from the gas supply source to the common gas outlet, bypasses the vaporizers, and adds 100% oxygen to the breathing circuit
Aspiration pneumonitis intraoperative management
-RSI vs mod RSI with ETT -if emesis occurs: turn head/tilt down, suction, intubation, bronch is aspiration of solid -PEEP to reduce shunt -bronchodilators for edema/IV lidocaine reduce neutrophil resp -if fever, leukocytosis, infiltrate likely; treat with abx if fever >48hrs
Why do some patients complain of shoulder pain?
-Secondary to peritoneal and diaphragmatic irritation from insufflated CO2 (incidence 27-47%) -phrenic nerve irritation -referred visceral pain, predominating on POD1 -resolves in 1-2 days
Lung Volume/Capacity key facts:
-TV = 6-8mL/kg -VC = 65-75mL/kg -FRC = 35mL/kg -lung volumes 20-25% smaller in women -spirometry cannot measure RV, therefore cannot measure TLC, FRC. CV or CC dynamic spirometry cannot measure
Definition of MAC:
-The minimum alveolar concentration required to produce anesthesia (lack of movement) in 50% of the population upon surgical stimulation. -It is age dependent in that the required dose peaks at approximately 6 months of age and then decreases with increasing age
Lidocaine cardiac IV indications include:
-Vfib, Vtach -stable wide complex tach -vent ectopy -prophylaxis MI arrythmias -thrombolytic therapy
You can smell isoflurane during a case. What should you do?
-abnormal finding -threshold for smelling VA is 5-300ppm, above NIOSH standard of not >2ppm -poor mask fit, unscavenged technique like insufflation, VA turned on before mask on, VA exhaled into room at end of case, spilled agent, uncuffed ETT/leak around LMA, machine not checked for leaks
What measures can be instituted preoperatively to reduce perioperative complications in patients with chronic bronchitis?
-abx if purulent sputum & infiltrates on x-ray -chest PT -hydration -smoking cessation (8 weeks of cessation pulm complications same as nonsmoker)
Regardless of the level of preoperative blood pressure control, many patients with hypertension display an...
-accentuated hypotensive response to induction of anesthesia -followed by an exaggerated htn response to intubation -htn pts may display exaggerated response to both endogenous catecholamines (from intubation or surgical stimulation) & exogenously adm symp agonist
Hypoxic Pulmonary Vasoconstriction (HPV)
-active response of lung to low alveolar PO2 (not PaO2) -vasoconstriction of pulmonary circulation in hypoxic area -blood diverted to better ventilated areas, improving systemic oxygenation
PONV can cause the following associated morbidities:
-airway compromise -bleeding, dehydration -electrolyte abnormalities -esophageal rupture (Boerhaave's syndrome) -wound dehiscence
The blood/gas solubility coefficient of an anesthetic is:
-an indicator of the speed of uptake (onset) and elimination (emergence) -reflects the proportion of anesthetic that will be soluble in the blood, "bind" to blood components, and not readily enter the tissues (blood phase) versus the fraction of the drug that will leave the blood and quickly diffuse into the tissues (gas phase).
Factors that lead to exaggerated hypotension during induction of htn patient
-antihypertensives & ga are vasodilators or cardiac depressants -htn pts present volume-depleted -sympatholytics attenuate protective circulatory reflexes (reduce symp tone & enhance vagal activity)
Complications of SADs include?
-aspiration during insertion & ventilation -inflation of the stomach, regurgitation, apiration of gastric contents (reduced with 2nd gen devices) -malpositioned, cuff overinflated -airway obstruction -use with caution in lateral and prone positions
In emergency situations, the minimum anesthesia equipment check will include:
-backup O2 cyclinder -suction -high pressure leak check
Trachea (windpipe)
-begins at C6 -ends at T4-5 at carina -2.5cm wide, 10-13cm long -20 semi-circular (C-shaped) rings -capacity 30ml (20% dead space) -sensory innervation: vagus -blood supply - inferior thyroid a., superior thyroid a., bronchial a., internal thoracic a.
How would you prepare for a Robotically assisted laparoscopic prostatectomy?
-both arms tucked -consider significant blood loss, type and crossmatch -2 large bore IV -arterial line (if expect large blood loss) -Bean bag underneath patient to prevent from sliding, no shoulder restraints, or braces (brachial plexus injury)
There is controversy with the use of N20 anesthetic gas in laparoscopic procedures due to...
-bowel distension -inc PONV (use of 70% N20)
Side effects of β-blockers
-bradycardia -AV block -hypotension -myocardial depression -bronchospasm -inhibit glucose metabolism
Heart rate changes during insufflation:
-bradycardia or tachycardia: d/t peritoneal stretch, hypercarbia, hypoxia, capnothorax, PE -prolonged QT with high pressure insufflation -bradycardia d/t inc vagal tone, distention on vagus nerve
Clinical effects of a T1-4 block
-cardiac sympathetic fibers blocked -bradycardia, hypotension
HTN leads to
-chronic vasoconstriction -intravascular volume deficit -myocardial hypertrophy & CHF -exacerbated atherosclerosis (turbulent flow)
List the complications associated with an infraclavicular block
-chylothorax (left-sided blocks) -thoracic duct on left, if damaged lymph fluid can accumulate in pleural cavity -hematoma: axillary nerve/vein punctur
How does epidural blood patch work?
-clot formation that seal dura & inc CSF pressure -success rate inc if performed >24hrs -if failed, repeat in 24hrs -if two failed, seek alternative diagnosis
How would you manage an intraoperative gas embolism during a laparoscopic case?
-d/c gas insufflation and N20 -100% FiO2 -release pneumoperitoneum -flood surgical field with NS -left lateral decubitus position (prevent gas from entering lungs) -attempt to aspirate gas via CVC -supportive measures to maintain
CIED interrogation includes:
-date of last interrogation -type of device, model -indications -battery life -lead integrity -PM function & underlying rhythm or ICD therapy -magnet response -any alerts
Why would a deep extubation be advantageous in the asthmatic patient?
-dec risk of bronchospasm d/t suppresion of airway reflexes
Tension pneumothorax characteristics and treatment:
-decreased CO, BP -inc CVP -hypoxia -hypotension -tachycardia -inc PAP Tx: 14g needle decompression at 2nd or 3rd anterior IC space or 4th or 5th lateral IC space (relieves tension), chest tube definitive tx
Anesthesia-related causes of V/Q mismatch:
-decreased FRC -supine dec FRC by 20% (also t-burg and reverse t-burg) -changes in thoracic muscle tone 20% -NMB: diaphragm shifts cephalad -retractors -PPV dep and nondep alveoli evenly ventilated -Sigh maneuvers increase FRC -GA significant dec in CO, esp with PEEP also pulm perfusion dec -GA shunt increases 10%
How are TLC, FRC, FEV1/FVC, and FVC altered in restrictive lung disease?
-decreased TLC, FRC, FVC -normal FEV1/FVC ratio
In intubated patient under general anesthesia, PE clinical presentation is limited to objective signs, such as...
-decreasing PetCO2 & tachycardia (1st signs) -decrease SaO2 -abg shows hypoxemia -abrupt PE: unexplained hypotension & tachycardia -inc PAP, CVP -bronchospasm -EKG: RAD, BBB, peaked T waves
Several techniques may be used before intubation to attenuate the hypertensive response...
-deep anesthesia with potent volatile agent -bolus of an opioid (fentanyl, 2.5-5 mcg/kg; alfentanil, 15-25 mcg/kg; sufentanil, 0.5-1.0 mcg/kg; or remifentanil, 0.5-1 mcg/kg) -adm lidocaine 1.5mg/kg IV, intratracheally, topical airway -β-adrenergic blockade with esmolol, 0.3-1.5 mg/kg; metoprolol 1-5 mg;or labetalol, 5-20 mg
Clinical effects of C3-5 block
-diaphragm & shoulders -respiratory compromise, need for intubation/ventilation, shoulder weakness (sign of resp comp)
Pulmonary mechanics: Inspiration
-diaphragm (C3-C5 phrenic n.) inc superior-inferior dimension of chest (descends 1-2cm normal breathing, 10cm forceful) -external intercostals inc anterior-posterior diameter -accessory m. include scm & scalene m. during forceful breathing
What treatments can reduce histamine release in patients treated with vancomycin 1gm over 10min infusion?
-diphenhydramine 1mg/kg -cimetidine 4mg/kg 1hr before induction
Possible reasons for collapse of ascending bellows during mechanical ventilation:
-disconnection of breathing tube -failed negative pressure relief valve -ventilator spill relief valve stuck open
What are the 5 tasks of oxygen in the anesthesia machine?
1. It proceeds to the fresh gas flowmeter. 2. Powers the oxygen flush. 3. Activates fail- safe mechanisms. 4. Activates oxygen low-pressure alarms. 5. Compresses the bellows of mechanical ventilators.
What can you do to fix an oxygen analyzer that is reading an FIO2 of 0.16 (and declining) during a general anesthetic?
-don't attempt to fix (trust) 1. call for help 2. turn on emergency o2 cylinder & disconnect pipeline from wall 3. if inspired o2 conc not inc, manually vent lungs with ambu bag with o2 (check for endobronchial intub if desat)
The pipeline supply of oxygen has failed. How can you make your emergency E tank oxygen supply last as long as possible?
-driving vent with cylinder cause rapid depletion -manually ventilate spontaneous ven if possible with n20 with o2 using low flows
PONV effective dose for droperidol and haloperidol?
-droperidol 0.625-1.25mg IV -haloperidol 0.5-2mg IV
Preparation (RSI)
-ensure patent IV access (2) -verify working equip & monitors: "SOAPME" -----Suction, Oxygen, Airway (ETT, blades, etc), Pharmacology, Monitoring, Equipment (crash cart, EtCO2, etc)
Primary site of action of epidural and spinal LA
-epidural = dural cuff -spinal = nerve roots in spinal cord
During the treatment of LAST, during reuscitation epinephrine should be used at what dose? What drugs are not recommended and should be avoided?
-epinephrine 10-100 mcg -vasopressin, CCB, β-blockers
Name 3 mechanisms on anesthesia machine that help prevent hypoxic mixture
-fail safe check valves -proportioning system -low oxygen alarm on analyzer
Which nerves does the 3 in 1 block, block?
-femoral n. -lateral femoral cutaneous nerve -obturator n.
Intraoperative management of acute PE
-first secure an airway -anesthetic agent must be d/c, adm 100% FiO2, PEEP -circulatory support (IV fluids/blood, norepi pressor of choice) -consider PAC -arrhythmia treated with lido or amio -if refractory thrombolysis or pulm embolectomy, severe cases CPB
How do you calibrate an oxygen analyzer? Types
-galvanic type (older plug in): expose to ra, should read 21% -paramagnetic sensor (new): use internal calibration, only need periodic (3-6mths) exposure to calibration
Patients at high risk for aspiration pneumonitis include:
-gastric pH <2.5 -gastric volume >25mL (0.4mL/kg) -OB population -trauma -emergency surgery -history of GI disease -obesity -diabetes -residual NMB blockade -somnolence -seizures -cardiac arrest
Pulmonary hypertension anesthetic implications
-give preop meds to reduce PVR -aggressive tx of hypotension -if dec SVR, give vasopressors -if inc PVR or RV failure, give nitric oxide or iloprost (also ccb, prostanoids, PDE5-I, ERA) -if loss atrial kick, restore NSR -epidural > spinal
Frank-Starling Law of the Heart
-greater the wall tension (preload), the greater the compensatory inc in contractility -allows heart to compensate for inc preload & avoid over distension by SV -there is a point at which inc in preload no longer in contractility and cause dec myocardial performance -inc preload, inc myocardial O2 demand
Clinical effects of C6-8 block
-hands and arms -paresthesia (tingling), weakness, accessory resp muscles
Epidural placement
-hat, mask, sterile gloves -sterile prep (betadine v. chloroprep -sterile drape -skin wheal (3ml 1% lido) -insert epidural needle, seat into ligamentum flavum -left hand supporting back/needle, right hand with LOR syringe -LOR, insert catheter 3-5cm past needle markings and withdraw needle slowly -give test dose (3ml 1.5% lido with 1:200,000 epi) -tape cath in place with yellow sponge & tegaderm
Pulmonary edema anesthetic management from PPT
-high FiO2, PPV, PEEP/CPAP -improve LV fx, myo O2 delivery, reduce LV afterload, reduce O2 req, dec preload from PPV -vasodilators (SNP), inotropes dopamine/dobutamine, steroids, diuretics (furosemide), morphine -fluid restriction, diuresis
Spinal and Epidural differences Epidural
-high dose (10-20ml) -slow onset (25-30min) -no sig nm block -multiple dosing possible -given at various points along backbone
Preoxygenate (RSI)
-high flow O2 for 3-5min @ highest conc (BVM, NRBM 15 lpm) -nitrogen wash out
PDPH conservative treatment
-horizontal position -adequate hydration -oral analgesics (NSAIDs) -IV caffeine (500mg, 70% efficacy) -oral caffeine (300mg) -theophylline -SPG block
Asthma pharmacologic treatment Corticosteroids
-hydrocortisone, dexamethasone, beclomethasone, prednisone -potentiate beta-agonists -stress dosing if took 2 week course within 6 months (hypotension could be adrenal suppression, hydrocortisone 100mg q8h perioperatively, reduce dosing POD1)
Why do you see reduced PaO2 immediately postop? Why might you see a delayed reduction?
-hypoventilation (opiates, benzos) -inhibited HPV from volatile anesthetics -increased O2 consumption: shivering, pain, hemorrhage/blood loss, surgical trauma Delayed d/t dec FRC & V/Q mismatch
Age-related pulmonary changes anesthetic considerations:
-impaired gas exchange = risk resp failure -dec compliance = inc WOB (careful use of NDMR, opioids, benzos) -inc V/Q mismatch = avoid inc press/large VT -inc CV, inc anatomic Vd, dec PaO2 = recruitment maneuvers, consider regional/LA -dec vent resp to hypoxia & hypercarbia -dec resp muscle strength = ineff cough
The elderly experience decrease pulmonary elastic recoil which leads to the following respiratory changes:
-inc RV, CV, FRC -dec VC, IRV, ERV, FEV1, FVC -inc dead space -progressing V/Q mismatch -PaO2 83mmHg >75years
Smoking facts
-inc airway CV -airway hyperreactivity -flattened diaphragm: dec inspiratory force & volume -minute ventilation 1.5-2x of nonsmoker -CO2 retention, CA -2-6x inc risk post-op pna
Post Dural Puncture Headache (PDPH)
-incidence 0.2%-24% -dec CSF volume/pressure in subarachnoid space, meninges stretch
Pumping effect
-increases vaporizer output -anything causing gas that has left the vaporizer to re-enter the vaporizing chamber can cause pumping effect -usually due to positive pressure ventilation or use of o2 flush valve
Respiratory anesthetic considerations for patients with obstructive lung disease
-regional good choice if min sedation & sensory level <T6 -GA: mask or LMA, avoid instrumenting/irritating the airway -low-dose benzos -opioids: careful titration, avoid blunting response to hypoxia/hypercarbia -VA: non-pungent less irritating & less resp depression (sevoflurane), VA decrease HPV
Peak plateau pressure
-relationship between volume and compliance -reflects the pressure it takes to hold a given volume inside the lungs -measured during end-inspiration -To prevent lung injury, alveolar pressure (aka the plateau pressure) should be kept <30 cmH2O -high alveolar pressures also d/t excessive Vt, gas trapping, PEEP, low compliance
Atlanto-occipital joint mobility
-required for sniffing position -better alignment of oral, pharyngeal, & laryngeal axes -pt seated upright, face forward, asked to lift head back with chin up as far as possible -if ext reduced to 23deg, visualization may be diff
What are the two most common arterial blood gas findings in the asthmatic patient?
-respiratory alkalosis -hypocarbia
What are clinical signs of respiratory acidosis?
-rise (later fall) in HR and BP -tachypnea -SNS activation (flush, arrhythmia, sweat) -inc surgical site bleeding
interscalene blocks at the ________ supraclavicular blocks at the _______ infraclavicular blocks at the ______ axillary blocks at the _______
-root level -trunk level -cord level -branch level
Neuraxial anesthesia relative contraindications
-sepsis -uncooperative patient -neuro deficits (DM with neuropathy) -demyelinating lesions -stenotic valve lesions -hypertrophic obstructive CM -severe spinal deformity -unknown duration of surgery
From skin to spinal cord
-skin -subq tissue -supraspinous ligament -interspinous ligament -ligamentum flavum -dura mater -arachnoid space -pia mater -spinal cord
Clinical effects of intracranial spread
-slurred speech, sedation, loc
Anesthesia use for magnet placement over ICD?
-stop inappropriate tachytherapy -inactivation ICD detection is rec for procedures using monopolar electrosurgery or RF ablation above umbilicus -use defib pads if magnet used, don't place directly over device -if magnet used, interrogate postop
Anion gap
-the difference between Na+ and sum of Cl- and HCO3- anions -normal - 3-11 mEq/L (if albumin norm) ->11: lactic or keto acidosis -hyperchloremic metabolic acidosis - over-adm of NS, will have normal AG
What is an airway exchange catheter (AEC)?
-they facilitate interchanging an ETT and/or extubating the trachea -capable of gas exhange using either jet ventilation or oxygen insufflation from an adapter & bag mask
OSA anesthetic management:
-thorough airway exam, anticipate difficult airway -CPAP (bring from home, induction, postop) -rapid desat d/t dec FRC -positioning HOB uprt, ramping -regional when appropriate -consider awake intubation -resp dep risk, opioids sparingly (consider MMA) -prolong PACU stay, SpO2 monitoring, overnight obs
What are the five nerves blocked with an ankle block?
-tibial -superficial peroneal -saphenous -sural -deep peroneal (nerves begin with S are purely sensory, other 2 sensory and motor)
Pneumoperitoneum renal effects?
-transient inc in creatinine clearance -oliguria -dec renal blood flow -ADH release -inc PaCO2, SNS resp, renal vasoconstriction
What is the FGF required to prevent rebreathing?
-two to three times minute ventilation -many use a min FGF of 5L/min
Chronic hypertension and anesthesia
-uncontrolled preop htn = inc incidence of preop hemodyn instability & MI -bp >180/110 indep pred for periop CV complications -possible delay if dbp >110 -BP goal within 20% of baseline
Anesthetic risk factors which increase risk of PONV include:
-use of volatile anesthetics -N20 (>50%) -Neostigmine -Opioids
How much volume of LA should be injected during a PNB?
-usually 25ml adequate -30-40ml most common
what are the 5 standards of monitoring
-ventilation- (ausc, chest rise/fall, etco2, o2sat, vent pressure monitors)-oxygenation- cont.-CV status- cont. (bp,hr q5min)-body temp- peds-NM- when blockers used positioning
Factors that impair HPV include:
-volatile anesthetics >1-1.5 MAC -PDE inhibitors, dobutamine, some CCB -phenylephrine, epinephrine, dopamine
Intraop hemodynamic stability management tips
-volume resuscitation -adequate analgesia (consider regional) -catecholamine replacement if dependent -consider gtt instead of bolus to minimize swings
Patient risk factors for PONV include:
-women -nonsmoker -hx of motion sickness -previous episodes of PONV
The impaired response to acute hypoxia occurs at...?
0.1 MAC (by contrast, 0.1 MAC does not impair response to PaCO2)
A circle system with fresh gas flows of ______ to ______ (closed circuit) provides near-total rebreathing, and full reliance on absorbent to prevent rebreathing of CO2.
0.3 to 0.5 L/min
The recommended initial dose of SNP is _____________ titrated to a maximum rate of _________, with the maximum rate not to be infused longer than __________
0.3 μg/kg/minute IV 10 μg/kg/minute IV 10 minutes
In what order does regression of spinal anesthesia occur? (1 recovers first and 4 recovers last) Pinprick Motor Function Touch Temperature
1 = Motor Function 2 = Touch 3 = Pinprick 4 = Temperature (spinal nerves are anesthetized in the following order - preganglionic sympathetic, temp, pin prick, touch, motor. recover in opposite order)
Each marking on epidural needle are in _____ increments
1 cm
It is recommended that prophylactic antimicrobials should be administered intravenously within ______ of surgical incision
1 hour (abx tx not recommended for longer than 24hrs)
If inspired CO2 of more than _________ is detected on the capnograph, the fresh gas flow should be increased to __________? This configuration converts the system to a ________________ configuration, in which rebreathing of exhaled gases is minimized.
1 to 3 mm Hg 5 to 8 L/min semi-open
What are some conditions that can increase the risk of complications with LMA use?
1. LMA too small 2. nitrous oxide (if cuff pressure not monitored) 3. non-supine position
HCO3- will change by _____ for every _______ change in PaCO2 depending on acute or chronic hypo-/hypercapnia
1-4 mEq 10 mmHg
During an epidural test dose, what questions to ask patients?
1. Any ringing in your ears? 2. Metallic taste? 3. Your heart beating fast? 4. Your legs numb all of sudden?
What is the NPO policy for the following liquids? Use the ASA Practice Guidelines.1. Breast Milk2. Apple Juice3. Cow's milkA. 6 HoursB. 4 HoursC. 2 Hours
1. Breast Milk B. 4 hours 2. Apple Juice C. 2 hours 3. Cow's Mike A. 6 hours
RSI post intubation management
1. CXR 2. Sedation: Benzo's, Propofol 3. Analgesia: Fentanyl 4. Ventilator Settings 5. Paralysis continuation IF needed
If pipeline pressure fails or FiO2 drops follow these steps:
1. Do not attempt to fix the oxygen analyzer—it must be trusted until it can be proved wrong. 2. Turn on backup oxygen cylinder on machine fully, and disconnect pipeline. Ensure that measured fraction of inspired oxygen begins to rise. If the fraction of inspired O2 does not increase (with fresh gas flow adequate to wash in the O2 quickly), ventilate the patient by Ambu bag with room air. 3. Use low flows of oxygen. Maintain anesthesia with a volatile agent. Ensure that Fio2 and agent concentration are appropriate. 4. Turn off the ventilator and ventilate manually through the circle system. 5. Call for help if needed; calculate the time remaining for the current cylinder; call for additional oxygen cylinders, and install them on the machine if needed. 6. Find out how long the problem is expected to last; participate in the hospital disaster plan, which may require prioritizing oxygen for those patients who need it most. 7. Do not reconnect patient to pipeline gas until the gas supply is tested. 8. If unable to use the circle, ventilate with an oxygen source (freestanding cylinder) or with room air via a bag-valve-mask device, and institute total intravenous anesthesia.
Midazolam (induction) 1. Dose: 2. Onset: 3. Duration:
1. Dose: 0.05-0.1 mg/kg (typical dose 4-8mg) 2. Onset: 1-2 min 3. Duration: 30-60 min (adjust dose in elderly, with opioids, liver/kidney disease)
Etomidate (induction) 1. Dose: 2. Onset: 3. Duration:
1. Dose: 0.3 mg/kg 2. Onset: 1 min 3. Duration: 30-60 min (avoid multiple doses, risk adrenal axis suppression)
Vecuronium (paralytic) 1. Dose: 2. Onset: 3. Duration:
1. Dose: 0.3 mg/kg 2. Onset: 60-90 sec 3. Duration: 90 min!
Rocuronium (paralytic) 1. Dose: 2. Onset: 3. Duration:
1. Dose: 0.6-1.2 mg/kg 2. Onset: 60 sec 3. Duration: 30-60 min
Succinylcholine (paralytic) 1. Dose: 2. Onset: 3. Duration:
1. Dose: 1-1.5 mg/kg 2. Onset: 45 sec 3. Duration: 4-6 minutes (avoid in hyperkalemia, RF, burns)
Ketamine (induction) 1. Dose: 2. Onset: 3. Duration:
1. Dose: 1.5-2 mg/kg IV or 3-5 mg/kg IM 2. Onset: 60 seconds 3. Duration: 15-30 min (good alternate for pts with reactive airway dis or hypotension) (pain control dose 0.5mg/kg, then 10mcg/kg/min)
Propofol (induction) 1. Dose: 2. Onset: 3. Duration:
1. Dose:1-2.5 mg/kg 2. Onset: 15-45 sec 3. Duration: 10-15 minutes
Traditional methods of confirming ETT placement include
1. ETCO2 3-6 breaths (gold standard in anesthesia for verification) 2. bilateral breath sounds 3.. symmetrical chest wall movement 4. epigastric auscultation 5. observation of tube condensation 6. lack specificity (all methods except ETCO2 can be misleading)
Guidelines for Treatment of Hyperkalemia:
1. IV CaCl, Ca gluconate 2. IV sodium bicarbonate (5-10min onset, 1-2hrs duration) 3. 10 units reg insulin/50ml D50W 4. K+ binding resins in GI tract 5. Diuretic 40mg Furosemide 6. Dialysis 7. albuterol. hyperventilation
What is the fire triad?
1. Oxidizer 2. Ignition Source 3. Fuel
Treatment for laryngospasm include:
1. Remove stimulus (e.g., suction the pharyngeal space) 2. Administration of 100% oxygen 3. Provide an open and clear airway (e.g., placement of an oral airway) 4. Perform a jaw thrust (e.g., Larson maneuver or pressure on the laryngospasm notch) 5. Apply positive-pressure ventilation (e.g., 10-30 cm H2O pressure-beware of gastric insufflation) 6. Consider deepening the anesthesia with propofol (e.g., 0.5 mg/kg IV) 7. Administer succinylcholine (e.g., 0.2-2 mg/kg IV or 4-5 mg/kg IM)
A-line waveform
1. Systolic upstroke 2. Systolic peak pressure 3. Systolic decline 4. Dicrotic notch 5. Diastolic run-off 6. End-diastolic pressure
Summary of Preanesthesia Check
1. Verify that auxiliary oxygen cylinder and self-inflating manual ventilation device are available and functioning. 2. Verify that patient suction is adequate to clear the airway.* 3. Turn on anesthesia delivery system and confirm that AC power is available. 4. Verify availability of required monitors, including alarms. * 5. Verify that pressure is adequate on the spare oxygen cylinder mounted on the anesthesia machine. 6. Verify that the piped gas pressures are 50 or greater psi. 7. Verify that vaporizers are adequately filled, and if applicable, that the filler ports are tightly closed.* 8. Verify that there are no leaks in the gas supply lines between the flowmeters and the common gas outlet. 9. Test scavenging system function. 10. Calibrate, or verify calibration of, the oxygen monitor and check the low oxygen alarm. 11. Verify that carbon dioxide absorbent is not exhausted. * 12. Conduct breathing system pressure and leak testing. * 13. Verify that gas flows properly through the breathing circuit during both inspiration and exhalation.* 14. Document completion of checkout procedures. * 15. Confirm ventilator settings and evaluate readiness to deliver anesthesia care. (ANESTHESIA TIME OUT)* * to be repeated before each case
What circumstances can permit a hypoxic mixture even when the hypoxic guard system is employed?
1. Wrong supply gas in oxygen pipeline or cylinder 2. Defective pneumatics or mechanics (the hypoxic guard system is broken) 3. Leaks downstream of flowmeter control valves 4. Inert gas administration (a third gas such as helium)
What are the two common reasons for an increase in inspired CO2?
1. absorbent granules have been exhausted 2. unidirectional valves are faulty (turns entire corrugated limb into dead space)
Standard extubation criteria: Respiratory Criteria
1. adequate respiratory mechanics -vital capacity > 15 mL/kg -maximal negative inspiratory force greater than -20 cm H2O -adequate Vt of at least 4-5 mL/kg 2. ability to maintain adequate oxygenation (with FiO2 < 50%) -SpO2 > 90% -PaO2 > 60 mm Hg 3. ability to maintain adequate alveolar ventilation -PaCO2 < 50 mm Hg 4. acceptable spontaneous rr
What are the 3 primary ways that CO2 is transported (buffered) in the blood?
1. as bicarbonate (70%) 2. bound to hgb as carbamino compounds (23%) 3. dissolved in plasma (7%) -bicarb reaction CO2 + H2O <--> H2CO3 <--> HCO3- + H+ --Cl- transported into rbc to maintain electroneutrality, known as chloride or Hamburger shift
While EtCO2 for three breaths is reliable indicator of successful intubation. What are situations that may yield a false-negative result?
1. cardiac arrest 2. severe bronchospasm 3. complete ETT obstruction (kinking/plugging) 4. equipment malfunction
What factors slow emergence?
1. elderly 2. hypothermia 3. hypoglycemia 4. hypotension 5. hypermagnesemia/nmb residual
List the correct sequence of anesthesia:
1. induction 2. maintenance 3. emergence
What are 4 strategies that can be used to manage the hyperdynamic response of tracheal intubation?
1. lidocaine (IV or laryngotracheal) 2. reduce duration of airway manipulation 15 sec or less 3. b-blocker before induction 4. fentanyl prior to induction
What are some complications associated with LMA use?
1. nerve injury: RLN, hypoglossal, lingual 2. pharyngeal necrosis 3. trauma to uvula 4. sore throat
Connect the correct parings: 1. Oral ETT in women 2. Oral ETT in men 3. Nasal ETT in men 4. Nasal ETT in women A. 25 cm B. 27 cm C. 23 cm D. 21 cm
1. oral ETT women D. 21 cm 2. oral ETT men C. 23 cm 3. nasal ETT women A. 25 cm 4. nasal ETT men B. 27 cm
What are the 7 P's of rapid sequence intubation?
1. preparation = 10min b4 intubation 2. preoxygenation = 5min b4 induction 3. pretreatment = 3min b4 induction 4. paralysis with induction = induction 5. protection = 30s after induction 6. placement (intubation) = 45s after induction 7. post-intubation management = 60s after induction
Diastole phase
1. rapid inflow - ventricular pressure below atrial pressure, mitral valve open, passive fill of ventricles 2. reduced inflow (diastasis) - min changes in volume & pressure 3. atrial systole - final period of rapid filling, atrial kick
After extinguishing airway fire, follow these steps
1. re-establish ventilation 2. avoid oxidizer-enriched atmosphere if clinically appropriate 3. examine tracheal tube to see if fragments may be left behind in airway 4. consider bronchoscopy 5. Assess patient status and devise plan for managment
In the case of an airway fire, immediately, without waiting follow these steps...
1. remove tracheal tube 2. stop the flow of all airway gases 3. remove sponges and any other flammable material from airway 4. pour saline into airway
List all the predictors of difficult laryngoscopy:
1. small mouth opening 2. prominent overbite/retrognathic jaw (short jaw) 3. inability to bite upper lip with lower teeth (mandibular protrusion test class three) 4. long incisors 5. Mallampati class three or four 6. high, arched palate 7. short, thick neck 8. short thyromental distance 9. reduced cervical mobility
The explanations for the primary cause of upper airway obstruction during anesthesia and sedation are:
1. tongue obstructs airway - genioglossus muscle relaxes & allows tongue to obstruct airway 2. soft palate obstructs the airway - tensor palatine muscle relaxes & allows the soft palate to obstruct the airway
The three cranial nerves that need to be anesthetized to perform an awake oral or nasal intubation are?
1. trigeminal nerve 2. glossopharyngeal nerve 3. vagus nerve
What percentage of the cardiac output goes to the following tissue groups: 1. vessel rich group 2. muscle & skin 3. fat 4. vessel poor group
1. vessel rich group (brain, heart, kidneys, liver) = 75% 2. muscle & skin = 20% 3. fat = 5% 4. vessel poor group = <1%
What percentage of body weight is accounted for by: 1. vessel rich group 2. muscle & skin 3. fat 4. vessel poor group
1. vessel rich group = 10% 2. muscle & skin = 50% 3. fat = 20% 4. vessel poor group = 20%
According to Hagberg, the two most reliable signs of endotracheal intubation are:
1. visualizing the ETT between the vocal cords 2. fiberoptic visualization of the tracheal rings with a fiberoptic bronchoscope
When administering IV lidocaine for MMA the American Pain Society suggests an induction dose of ______ followed by _______ intraoperatively
1.5 mg/kg 2 mg/kg/hr
When vancomycin (glycopeptide) is administered IV, the recommendation is to infuse the calculated dose, ________ over ________ to minimize the occurrence of drug-induced histamine release and hypotension. Begin_____ hrs prior to surgery for prophylaxis)
10 to 15 mg/kg 60 minutes 2 hours
In medical patients, what is a typical threshold for prophylactic platelet transfusion?
10,000/μL (normal 150,000-400,000μL)
The isoflurane dial is set to two percent. What percent of fresh gas exiting the vaporizing chamber is saturated with isoflurane?
100 FGF entering the vaporizing chamber becomes 100% saturated with volatile agent
The Eschmann stylet is a ___-French flexible stylet that is ______ in length with a ___ degree bent distal tip.
15 60cm 40
Short duration of action of esmolol is returns the heart rate to predrug levels within _______ after discontinuing the drug
15 minutes
Calculate the total amount of oxygen carried in the bloodstream if the hemoglobin is 12.8g/dL, the PaO2 is 98mmHg, and the O2 saturation is 96%
16.76mL/dL (12.8g/dL x 1.34mL/g x .96) + (98 x 0.003) = 16.76mL/dL
What is the most common epidural needle used?
17g Tuohy
What is the pressure of gasses flowing through a variable bypass vaporizer?
17psi (low pressure)
Calculate the amount of oxygen bound to hemoglobin if the patient's hemoglobin level is 14.5g/dL and the O2 saturation is 97%
18.8mL/dL 14.5g/dL x 1.34mL/g x 0.97 = 18.8ml/dL
Cormack and Lehane score
1: Full view of glottis 2a: Partial view of glottis 2b: posterior ext of glottis or only arytenoids 3: Epiglottis only 4: No epiglottis or glottis -grade 2b or worse predicts difficult intubation
For every ______ change in pressure, there is ______ change in volume
1cm H2O 100-150mL
Epidural catheter markings 1st single marking Double marking Triple marking
1st single marking - 5cm double marking - 10cm triple marking - 15cm
Double-burst stimulation consists of two short bursts of a 50-Hz tetanus separated by 0.75 seconds. Fade of the second impulse is comparable to a TOFR of.....
<0.6 and indicates significant paralysis
Sugammadex should be avoided in patients with a creatinine clearance of...?
<30 mL per minute (dialysis does not effectively remove the complex)
Oxygen low pressure alarm sounds if pressure falls below?
<30psi
Sinus bradycardia is frequently seen in children and in adults after a repeated dose of succinylcholine due to stimulation of cardiac muscarinic receptors, what is the treatment?
Atropine is effective in treating or preventing bradycardia
Epidural distance from skin to epidural space
Average adult - 4-6cm Obese adult - 8cm Thin adult - 3cm (average 5cm)
Bohr vs Haldane effect
Bohr - describes o2 carriage, says CO2 & dec pH cause erythrocyte to release o2 Haldane - is opposite, describes CO2 carriage, says o2 causes erythrocyte to release CO2
The cricoid cartilage is an anatomic landmark that corresponds to the vertebral body of
C6
Using the Mallampati score, what structures are visible in: Class I: Class II: Class III: Class IV:
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 -Remember PUSH -Class III/IV difficult intubation
Nicardipine (Cardene IV) Class, Dose, Conc, Onset, half-life, Duration, metabolism, SE
Class: CCB Dose: 5-15mg/hr, 100mcg Conc: 2.5mg/mL, 40mg/200mL 0.9%, 20mg/200mL 0.9% Onset: 2-10min half-life: 2-4hrs Duration: 30-60min Metabolism: hepatic CYP450 SE: flushing, pedeal edema, angina, hypotension, headache, dizzinesss
Amiodarone (Cordarone) MOA, Dose, Onset, Conc, half-life, SE
Class: Class III (inhibit K+ ch) MOA: prolong refract period, antiadrenergic effect, minor neg inotropic, dil coronary arteries/inc coronary bf EKG: slow SR, prolong pr interval, wide QRS, prolong QT Dose: 150mg ovr 10min then 1mg/min 6hrs then 0.5mg 18hrs, Conc: 150mg/3mL, 450mg/9mL, 900/18mL Onset: within hrs half-life: 29 days Duration: wks to mths Metabolism: CYP450 SE: pulm tox, hypotension, optic neuropathy, hyper/hypothyroidism
Labetalol Class, Dose, Conc, Onset, half-life, Duration, metabolism, SE
Class: alpha1 β1 β2 blockers (1:7 ratio) Dose: 50-300mcg/kg/min Conc: 5mg/mL Onset: 1-5min half-life: 6min Duration: 1-4hrs Metabolism: hepatic, ext 1st pass SE: orthostatic hypotension, dizziness, fatigue, nausea, edema, vent arrhythmia
Nitroglycerin Class, Dose, Conc, Onset, half-life, Duration, metabolism, SE
Class: antianginal, vasodilator Dose: 5-300mcg/kg/min Conc: 5mg/mL, 200mcg/mL 5%, 100mcg/mL 5% Onset: 1-2min half-life: 1-3min Duration: 5-10min Metabolism: 1st pass, hepatic SE: headache, hypotension, orthostatic, syncope, dizziness, bradycardia
Hydralazine Class, Dose, Conc, Onset, half-life, Duration, metabolism, SE
Class: arteriolar dilator Dose: 5-20mg Conc: 20mg/mL Onset: 5-20min half-life: 2-8hrs Duration: 1-8hrs Metabolism: hep acetylated, ext 1st pass oral SE: orthostatic hypotension, reflex tachycardia, palpitation
Lidocaine (Xylocaine) MOA, Dose, Onset, Conc, half-life, SE
Class: class 1b anti-arrhythmic, amide LA, blocks NA+ ch Dose: 1-1.5mg/kg, max dose 300mg/hr IV Conc: 4%/mL, 2%/mL, 1.5%/mL, 1%/mL, 0.5%/mL Onset: 45-90s half-life: 7-30min, terminal 1.5-2hrs Metabolism: hepatic SE: headache, shivering, resp depression, bradycardia, hypotension, cauda equina syn,
Nitroprusside (Nipride) Class, Dose, Conc, Onset, half-life, Duration, metabolism, SE
Class: direct venous/arteriolar dilator Dose: 0.25-4mcg/kg/min Conc: 25mg/mL, 50mg/100mL 0.9%, 20mg/100mL 0.9% Onset: 1-2min half-life: <10min Duration: 1-10min Metabolism: combines with hgb to produce cyanide & cyanmethemoglobin SE: bradycardia, hypotension, methemoglobinemia, irritation at inj site
Ketorolac Class, Dose, Conc, Onset, half-life, Duration, metabolism, SE
Class: nonselective nsaid Dose: 15-30mg qd-qid Conc: 30mg/mL, 15mg/mL Onset: 30min half-life: 2.5-8.5hrs Duration: 4-6hrs Metabolism: conjugation SE: headache, gi pain, prolonged bleeding time, gi bleed, anemia, renal fx abn
Metoprolol Class, Dose, Conc, Onset, half-life, Duration, metabolism, SE
Class: β1 blockers Dose: 1-5mg Conc: 5mg/5mL Onset: 1-5min half-life: 3-7min Duration: 1-4hrs Metabolism: CYP2D6, first pass 50% SE: bradycardia, hypotension, AV block, bronchospasm
Esmolol (Brevibloc) Class, Dose, Conc, Onset, half-life, Duration, metabolism, SE
Class: β1 blockers Dose: 50-300mcg/kg/min Conc: 100mg/10mL Onset: 1-2min half-life: 9min Duration: 1-4hrs Metabolism: RBC esterases SE: hypotension, peripheral ischemia, nausea, infusion site reaction
Epidural needles differ by amount of curvature at the needle tip. Crawford Hustead Tuohy
Crawford - 0 degrees Hustead - 15 degrees Tuohy - 30 degrees (minimize risk of dural puncture)
PT is _________ pathway Which factors?
Extrinsic (3 and 7)
What factors increase and decrease potency?
Factors Increasing Potency: inhaled anesthetics, antibiotics, hypothermia, hypermagnesia, large doses of local anesthetic, quinine Factors Decreasing Potency: anticonvulsant therapy hypercalcemia, hyperparathyroid (onset is inversely proportional to potency)
Why does fade occur?
Fade occurs because the nondepolarizing drugs block presynaptic ACh receptors (AChRs) in addition to their classic antagonist effect at postsynaptic ACh neuromuscular junction sites
Factors that can affect induction rate: Faster induction
Faster Induction Low blood gas solubility Low cardiac output High minute ventilation High fresh gas flows High concentration(overpressuring) Second gas effect
Peripheral nerve block indications Femoral Fascia iliaca Sciatic Popliteal Ankle
Femoral = anterior thigh & knee, medial lower leg Fascia iliaca = hip, femoral shaft & knee Sciatic = below knee sparing medial lower leg Popliteal = below knee sparing medial lower leg Ankle = foot and distal ankle
Components of Low Pressure System
Flowmeter tubes Vaporizers Check valve (if present) Common gas outlet
4-2-1 rule
For maintenance IV fluid calculation: 4 mL/kg/hr for first 10 kg 2 mL/kg/hr for next 10 kg 1 mL/kg/hr thereafter Example: a 75 kg patient 10kg x 4ml/kg/hr = 40ml/hr 10kg x 2ml/kg/hr = 20ml/hr à 75kg -20 kg = 55 kg 55kg x 1ml/kg/hr = 55ml/hr à maintenance rate: 40 + 20 + 55 = 115 ml/hr
What is the best indicator of how patient will tolerate stress of surgery & anesthesia? Two questions?
Functional capacity (METs) >= 4 METS: proceed to surgery <= 4 METS: inc incidence of postop cardiac complications 1. Are you able to walk four blocks without stopping? 2. Are you able to climb two flights of stairs without stopping?
_____________does not easily cross the blood-brain barrier and thus is not likely to cause central anticholinergic syndrome
Glycopyrrolate (0.2-0.3mg) IV
ASA Physical Status Classification
I - healthy II - mild systemic disease III - severe systemic disease IV - severe systemic disease that is a constant threat to life V - moribund and not expected to survive without the procedure VI - brain-dead and organs being removed
Stages of Anesthesia
I: Induction; the period between administration of anesthesia and loss of conciousness II: Excitement phase; the period after loss of consciousness and before surgery III: Surgical anesthesia; the period in which surgery is performed IV: Overdose; the period between respiratory arrest and death from circulatory collapse
Spirometry Volumes IRV TV ERV RV TLC VC IC FRC FEV1 FEV1/FVC%
IRV = 3000mL TV = 350-500mL ERV = 1100mL RV = 1200mL TLC = 5800mL VC = 4500mL IC = 3500mL FRC = 2300mL FEV1 = 4000mL, 75% of FVC FEV1/FVC% =80%
Which nerves are included in an axillary block? Which nerves require a separate block?
Included - medial, radial, ulnar Field block - intercostobrachial & musculocutaneous n. (inj into coracobrachialis 3-5ml)
Which factors increase FA/FI = Faster onset (curved pushed up):
Increase wash in -High FGF -High alveolar ventilation -Low FRC -Low time constant -Low anatomic dead space Decrease uptake Low solubility Low CO Low Pa-Pv difference
Increased pulmonary changes in the elderly include:
Increased -RV, CC, FRC -chest wall rigidity -A-P diameter (barrel) -central airway sz -lung compliance -Aa gradient -Vd
oxyhemoglobin dissociation curve factors causing left shift
Increased affinity for O2 (left=love) -decreased temperature -decreased 2,3-DPG -decreased CO2, H+ -increased pH -increased HgbMet -increased HgbCO -increased Hgb F
Factors that influence MAC:
Increases in MAC -hyperthermia -drug-induced increases in CNS activity -hypernatremia -chronic alcohol abuse Decreases in MAC -hypothermia, inc age, preop sedatives, drug-induced dec in CNS activity, a2 agonists, acute alcohol ingestion, pregnancy, postpartum, lithium, lidocaine, hypoxia, hypotension, CPB, hyponatremia
Propofol dosing Induction GA maintenance Procedural sedation
Induction: 1-2.5mg/kg GA maintenance: 100-200mcg/kg/min Procedural sedation: 25-75mcg/kg/min
Peripheral nerve block indications Interscalene Supraclavicular Infraclavicular Axillary Elbow/wrist Intercostal TAP Psoas compartment
Interscalene = shoulder & upper arm Supraclavicular = entire upper extremity distal to shoulder Infraclavicular = elbow and below Axillary = distal to elbow Elbow/wrist = wrist & hand Intercostal = chest & upper abd wall TAP = anterior abd wall Psoas compartment = hip, thigh, medial lower leg
Extracellular Volume (ECV)
Interstitial volume (16% of total body weight) + Plasma fluid( 4% of total body weight)
During epidural test dose, what symptoms will be noted if intrathecal or intravascular?
Intrathecal - warmness to feet, leg weakness. Stop inj, restart at another level Intravascular - HR inc 20% or >30bpm within 30sec, ringing in ears, metallic taste, numbness on lips/face. Stop, restart at another level
PTT is ___________ pathway Which factors?
Intrinsic (8, 9, 11, 12)
Ischemia = Infarction =
Ischemia = ST depression Infarction = ST elevation
Which benzodiazepine is less dependent on hepatic enzymes and undergoes phase 2 conjugation and is ideal for use in liver disease?
Lorazepam
Causes of increased compliance
Loss of elastic recoil of tissue, alveolar destruction -emphysema -+- asthma -+- chronic bronchitis -age
Maximum allowable blood loss (MABL)
MABL = EBV x (Initial Hct - Lowest Acceptable Hct)/Initial Hct
Succinylcholine MOA, Dose, ED95, Conc, half-life, metabolism, SE
MOA: Dep NMB Dose: 1-1.5mg/kg (60s) ED95: 0.3mg/kg Conc: 20mg/mL half-life: 47sec metabolism: hydrolysis by butyrlcholinesterase SE: bradycardia, myoglobinuria, hyperkalemia, inc IAOP/ICP, inc ICP, myalgia, masseter spasm (MH indicator)
Midazolam (Versed) MOA, Conc, Dose, metabolism, half-life, CNS, CV, Pulm
MOA: GABA agonist Conc: 10mg/2mL, 5mg/mL, 5mg/5mL, 2mg/2mL Dose: preop anxiety 1-2mg IV, induction 0.05-0.1mg/kg (typical dose 4-8mg) metabolism: CYP3A4 half-life: 3hrs CNS: anterograde amnesia, sedation, anxiolysis CV: hypotension, bradycardia Pulm: resp dep, apnea
Etomidate (Amidate) MOA, Conc, dose, half-life, metabolism, CNS, CV, Pulm, Misc
MOA: GABA modulation Conc: 2mg/mL Dose: 0.3mg/kg/IV half-life: 2-5hrs metabolism: ester hydrolysis CNS: dec CBF, CMRO2, IAOP, myoclonia CV: inc bp d/t alpha agonist, sig dec bp with aortic/mitral disease Pulm: dec min vent & vent resp to CO2, inc RR, potential apnea on induction Misc: adrenal supp, myoclonic, pain on inj, thrombophle, n/v, avoid multiple doses
Rocuronium moa, dose, ed95, conc, half-life, metabolism, SE
MOA: NDNMB Dose: 0.6-1.2mg/kg IBW ED95: 0.31mg/kg Conc: 100mg/10mL, 50mg/5mL half-life: 1.4-2.4hrs metabolism: min hepatic SE: inc peripheral vasc resistance, tachycardia, htn
Ketamine (Ketalar) MOA, Conc, Dose, half-life, metabolism, CNS, CV, Pulm, Misc
MOA: NMDA rec antagonist Conc: 100mg/mL, 50mg/mL, 10mg/mL Dose: induction 1.5-2mg IV, 3-5mg IM, pain management 0.5mg IV then 10mcg/kg/min infusion Metabolism: hepatic (conjugat) half-life: 2-3hrs CNS: psychomimetic, nightmares, diss anesthesia, inc CBF & IOP, atypical anesthesia on EEF, no dec BIS or EP CV: inc bp, hr, contract, co, cvp Pulm: inc comp, dec pulm resistance, bronchodilating Misc: inc trach, bronch, salivary secretions
Neostigmine (Bloxiverz) MOA, Dose, Onset, Conc, half-life, metabolism, SE
MOA: acetylcholinesterase inhib Dose: 0.03-0.07mg/kg (max 5mg) -2 TOF twitches Fade++++ 0.07mg -3-4 TOF twitches Fade+++ 0.04mg/kg Onset: 1-5min, Peak 7-14min Conc: 10mg/10mL, 5mg/10mL half-life: about 30min metabolism: hepatic SE: bradycardia, hypotension, bronchoconstriction, hypersalivation, diarrhea, n/v Misc: anticholinergic agent given in conjuction (0.03mg/kg for roc, 0.07mg/kg for vec & panc)
Dexmedetomidine MOA, Dose, Conc, metabolism, half-life, CNS, CV, Pulm
MOA: activates a2 receptor results in inhibition of adenyl cyclase and decreased cAMP level, 𝛼2 agonist to 𝛼1 (1600:1) Dose: 1mcg/kg over 10min then 0.2-0.7mcg/kg/hr (induction) Conc: 400mcg/100mL, 200mcg/50mL, 200mcg/2mL, 80mcg/2mL Onset/Duration: 10-20min/10-30min metabolism: hepatic N-glucuronidation/CYP2A6 half-life: up to 3hrs CNS: "wakeup test", dec BIS CV: hypotension, bradycardia Pulm: resp dep
Atropine MOA, Dose, Conc, onset, half-life, metabolism, SE
MOA: anticholinergic Dose: bradycardia (0.5mg q3-5min max 3mg), inhibit secretions (0.4-1mg), NMB rev (15-30mcg/kg) with neo, 7-10mcg/kg with edrophonium Conc: 8mg/20mL, 1mg/mL, 0.4mg/mL Onset: immediate half-life: 3hrs metabolism: hepatic SE: arrhythmias, tachycardia, ecg changes, laryngospasm, muscle twitch, cns changes
Glycopyrolate (Robinul) MOA, Dose, Onset, Conc, half-life, SE
MOA: anticholinergic, blocks ach at PNS sites Dose: 0.2mg for each 1mg of neo or 5mg of pyridostigmine Onset: 1min Conc: 4mg/20mL, 1mg/5mL, 0.4mg/2mL, 0.2mg/mL half-life: 1hr SE: flushing, tachycardia, headache, dry mouth, constipation, urinary retention -does not cross BBB
Sugammadex (Bridion) MOA, Dose, Onset, Conc, half-life, metabolism, SE
MOA: forms complex with roc or vec in plasma red nmbd at nmj Dose: 2mg/kg (mod block T2), 4mg/kg (1-2 PTC), 16mg/kg (immediate rev) Onset: <3min Conc: 500mg/5mL, 200mg/2mL half-life: about 2hrs metabolism: no met, 95% urine SE: hypotension, hypertension headache, n/v, pain at inj site
Propofol (Diprivan) MOA, half-life, dose, CNS, CV, Pulm, Misc
MOA: potentiates GABA/GABA-A agonist Conc: 1000mg/100mL, 500mg/50mL, 200mg/20mL Dose: 1-2.5mg/kg IV half-life: 1-2hrs CNS: dose-dep dec CBF, CMRO2, CPP, IOP, myoclonia, sedation CV: dec bp (dec SNS tone, vasodilation), bradycardia Pulm: resp dep, dec Vt>RR, dec vent resp to CO2, min bronchodil Misc:antiemetic, antipruritic, pain on inj
Laryngoscope blades
Macintosh blade (vallecula) - sz 3 for most adults Miller blade (lifts up the epiglottis) - sz 2 or 3 most adults
Intraop management of hypertensive patient Med management Expect Goal
Maintain med management -beta & alpha blockade -starting beta blockade inc risk of stroke & death -refractory hypotension from ACE-I Expect -exaggerated response to laryngoscopy & surgical stimulation -post-induction & intraoperative hypotension -assume some degree of CAD Goal -maintain adequate perfusion (CPP=DBP-LVEDP) -treat cause (OHM's Law)
Thyromental Distance (TMD)
Measured from thyroid notch to inner border of the mandible when patient's head is upright and maximally extended. Less than 6 cm may be difficult intubation.
Match each upper extremity nerve injury to its presentation. 1. Median 2. Ulnar 3. Radial a. Claw hand b. Wrist drop c. Inability to oppose thumb
Median = Inability to oppose thumb Ulnar = Claw hand Radial = Wrist drop
What is first pass metabolism?
Metabolism of a drug before it enters circulation; usually thru stomach, liver, intestine, rectum, lung.
Intubation dose, time to maximum block, and duration of action for: Rocuronium Vecuronium Atracurium Cisatracurium
Rocuronium = 0.6 mg/kg, 1.7 min, 36 min Vecuronium = 0.1 mg/kg, 2.4 min, 44 min Atracurium = 0.5 mg/kg, 3.2 min, 46 min Cisatracurium = 0.1 mg/kg, 5.2 min, 45 min
What should you do if the vaporizer is tipped over?
Run a high FGF through it for 20-30 minutes before using it for a patient
Lidocaine Toxicity (SAMS)
S-lurred Speech A-ltered Central Nervous System M-uscle Twitching S-eizures
What is the S1 sound? S2? What heart sound is heard at the end of diastole? end of systole?
S1 - AV valves closing S2 - Semilunar valves closing Systole - S1 Diastole - S2
pulse pressure
SBP-DBP = PP 40-50mmHg -inc pp = inc risk of heart disease & afib
Ventilation modes that could support a spontaneously breathing patient include...
SIMV, PSV, CPAP, and airway pressure release ventilation (APRV)
Tracheal extubation should be performed with the patient in what stage of anesthesia?
STAGE III - surgical plane of anesthesia or fully awake -if ext at stage II inc risk of laryngospasm
SV formula
SV = EDV - ESV Key factors -preload, afterload, contractility, wall motion abn, valvular do
SVR formula
SVR = (MAP-CVP)/COx80 800-1200 dynes/sec/cm5
Lidocaine is used principally for suppression of ventricular arrhythmias, having minimal if any effect on ____________
SVT (inability to alter the rate of spontaneous phase 4 depolarization)
What is the MAC value for Sevoflurane of an 80 year old man?
Sevo MAC 2% 4 decades x 6.7% 4 x 6.7% = 26.8% 2 x 0.268 = 0.536 (MAC decrease) 2-0.536 = 1.46 MAC
Which volatile agent has minimal HR effects?
Sevoflurane
MAC/blood gas partition coeff/oil gas partition coeff/at 37C of the following: Sevoflurane (Ultane) Isoflurane (Forane) Nitrous oxide Desflurane (Suprane)
Sevoflurane (Ultane) - MAC 2%, BG coeff 0.6, OG coeff 50 Isoflurane (Forane) - MAC 1.15%, BG coeff 1.4, OG coeff 99 Nitrous oxide - MAC 105%, BG coeff 0.47, OG coeff 1.4 Desflurane (Suprane) - MAC 5.8%, BG coeff 0.42, OG coeff 18.7
Volatile agents vapor pressure Sevoflurane Isoflurane Desflurane N20
Sevoflurane - 157 Isoflurane - 238 N20 - 38,770 Desflurane - 669
Steroidal NMB include:
Steroidal Compounds Pancuronium Vecuronium Rocuronium
_________ of β-adrenergic receptors occurs with chronic administration of β-adrenergic antagonists such that abrupt discontinuation of treatment may lead to supraventricular tachycardia
Upregulation
What is volume of distribution Vd?
Vd = amount of drug in body / [drug] in plasma dose of drug/plasma concentration of drug
The most common cause of a vaporizer leak is...
a loose filler cap
The internal laryngeal branch of the SLN provides sensation _______ the vocal cords, and the RLN provides sensation _______ the vocal cords
above below
In circle system if substantially increasing the fresh gas flow causes the inspired CO2 to decrease, the....?
absorbent granules are exhausted and should be replaced at the end of the case. (safest to change between cases). Do not attempt to increase minute ventilation (VE) by increasing tidal volume, respiratory rate, or both.
What is the purpose of antisialagogues during awake intubation?
administration of antisialagogue (atropine 0.5-1mg IV/IM or glycopyrrolate 0.2-0.4mg IV/IM) can help dry secretions and maximize view of laryngeal structures -works in 20min
Antimicrobials: Dose, half-life, redosing Ertapenem
adult dose - 1g Peds dose - 15mg/kg half-life 3-5hrs redosing interval - NA
Antimicrobials: Dose, half-life, redosing Ceftriaxone
adult dose - 2g Peds dose - 50-75mg/kg half-life 5.4-10.9hrs redosing interval - NA
Antimicrobials: Dose, half-life, redosing Ciprofloxacin
adult dose - 400mg Peds dose - 10mg/kg half-life 3-7hrs redosing interval - NA
Antimicrobials: Dose, half-life, redosing Clindamycin
adult dose - 900mg Peds dose - 10mg/kg half-life 2-4hrs redosing interval - 6
Antimicrobials: Dose, half-life, redosing Cefazolin
adult dose -2g, 3g >120kg Peds dose - 30mg/kg half-life 1.2-2.2hrs redosing interval - 4hrs
Treatment of LAST has undergone swift changes in last decade and includes prompt...?
airway management, circulatory support, and mechanisms to remove local anesthetic from the receptor sites (adm O2 at earliest sign of LAST)
absorption atelectasis
alveolar collapse that occurs when high concentrations of oxygen are given and oxygen replaces nitrogen in the alveoli; if airway obstruction occurs, the oxygen is absorbed into the bloodstream and the alveoli collapse
Mechanical ventilation increases ____________, which increases ventilation relative to perfusion. This explains why mechanical ventilation increases the Vd/Vt ratio to __________
alveolar pressure (PA) 0.50 or 50%
During treatment of LAST what drug is preferred to treat associated ventricular arrhythmias?
amiodarone
What are the four types of dead space?
anatomic - air confined to conducting airways (150mL, reduced with ETT) alveolar - alveoli are ventilated, not perfused physiologic - anatomic Vd + alveolar Vd apparatus - Vd added by equipment (face mask, heat moisture exchanger)
Pipeline pressure is?
approximately 50psi (344kPa)
Which modes of mechanical ventilation are BEST suited for a laryngeal mask airway? (2) a. controlled mandatory ventilation b. pressure support ventilation c. synchronized intermittent mandatory ventilation d. inverse ratio ventilation
b. c.
Which sequence of numbers correlates with the respective number of roots, trunks, divisions, cords, and branches in the brachial plexus? a. 6, 3, 5, 5, 3 b. 5, 3, 6, 3, 5 c. 5, 3, 4, 6, 5 d. 6, 5, 3, 6, 3
b. 5, 3, 6, 3, 5 -Roots: C5-T1 -Trunks: Superior, Inferior, Middle -Divisions: 3 anterior & posterior -Cords: Lateral, Posterior, Medial -Terminal Branches: Musculocutaneous, Axillary, Radial, Median, Ulnar (MARMU)
Which nerve roots are the MOST resistant to the effects of LA? (select 2) a. L3 b. L5 c. S1 d. S3
b. L5 c. S1 (largest spinal nerves, most resistant, L5-S1 largest interspace)
Which agent impairs the hypoxic ventilatory response the LEAST? a. sevoflurane b. desflurane c. isoflurane d. These drugs all produce similar degrees of depression
b. desflurane
What is the MOST common consequence of an epidural blood patch?
backache (also radicular pain, tx NSAIDs, antispasmodics. less common nerve palsies and bradycardia)
Why are β-adrenergic antagonists are not recommended for administration to patients with diabetes?
blunts warning sign of hypoglycemia (tachycardia)
After administration of succinylcholine, severe hyperkalemia is seen in what conditions?
burn, severe abdominal infections, severe metabolic acidosis, closed head injury, or conditions associated with upregulation of extrajunctional acetylcholine receptors (e.g., hemiplegia or paraplegia, muscular dystrophies, Guillain-Barré syndrome, and burn)
Degradation of desflurane and isoflurane produces...?
carbon monoxide
Lung compliance formula
change in volume/change in pressure
NMBA have a prolonged onset in the elderly, what is the agent of choice in this population? Why?
cisattricurium -undergoes Hoffman elimination, produces laudanosine
Recovery from succinylcholine-induced blockade occurs as succinylcholine _______ away from the neuromuscular junction, down a concentration gradient as the plasma concentration decreases
diffuses (Butyrylcholinesterase influences the onset and duration of action of succinylcholine by controlling the rate at which the drug is hydrolyzed in the plasma before it reaches, and after it leaves, the neuromuscular junction)
Volatile anesthetics effect on Tv, RR, response to CO2?
dose-dependent decrease (surgical stimulation helps to overcome respiratory-depressant effects of volatile agents) -relax smooth muscle, bronchodilation
What are the effects of volatile agents on EEG?
dose-related suppression (initial inc & later decline) in amplitude and decreased frequency
What is the dose, max, conc, onset, half life, and duration of flumazenil (Romazicon)?
dose: slow titration 0.2mg (2ml) IV up to 1mg until desired LOC achieved max dose: 3mg conc: 1mg/10mL, 0.5mg/5mL onset 1-2 min duration 45-90 min half life: 54min SE: seizure, n/v, arrhythmia, htn, pain at site (short duration makes it possible for re-sedation)
Definitive treatment for PDPH is?
epidural blood patch (90% cure rate)
Absorbents contain ______________ as an indicator of absorbent pH and changes to a blue-purple at a pH of ______.
ethyl violet 10.3
What are the induction doses of the IV anesthetics below: etomidate propofol dexmedetomidine midazolam
etomidate - 0.2-0.3 mg/kg propofol - 1-2 mg/kg dexmedetomidine 1 mcg/kg over 10 min then 0.2-0.7 mcg/kg/hr midazolam - 0.1-0.2 mg/kg
The ventilator relief valve opens only during the ____________ phase. During ___________, driving gas closes this relief valve, inflating the lungs by preventing gas within the bellows from exiting to the scavenger as the bellows are compressed.
expiratory inspiratory
During onset of a relaxant muscle group sensitivity exhibit the following pattern. Most sensitive to least sensitive:
eye muscles - extremities - the trunk - abdominal muscles - diaphragm (opposite during recovery)
Loss of Oxygen Pipeline Pressure If pressure loss is profound the oxygen low-pressure alarm sounds and...?
fail-safe valves halt the delivery of all other gases, some new machines switch to air to drive the ventilatory bellows
The elderly have a _______ propagation of pulse pressure waveform, _______ afterload, _____ SBP, and systolic function remains unchanged
faster increase increase
What are the induction doses for the following opioids: fentanyl sufentanil alfentanil remifentanil
fentanyl - 5-10 mcg/kg sufentanil - 1-30 mcg/kg alfentanil - 8-100 mcg/kg remifentanil - 0.5-1 mcg/kg
EKG septal ischemia and heart location affected
lead V1 and V2 LAD and septum
EKG lateral ischemia and heart location affected
leads I, aVL, V5, V6 circumflex
EKG Inferior ischemia and heart location affected
leads II, III, aVF right coronary artery (RCA)
EKG anterior ischemia and heart location affected
leads V3 and V4 LAD and diagonal
What drug is becoming a standard of care in the treatment of local anesthetic toxicity?
lipid emulsion (initial bolus of 1.5mL/kg followed by 0.25mL/kg per min for at least 10min after circ stability is attained)
What is the best way to detect a vaporizer leak?
low pressure test
Anesthetic agents with ____ solubility properties (low blood/gas coefficient) leave the blood _____ and enter the tissues, producing a rapid anesthetic state
low, quickly (Desflurane 0.42:1)
How to calculate how much liquid anesthetic is used
mL of liquid anesthetic used per hour = vol% x FGF (L/min) x 3
ETT sizes
man - 7.5-8.5mm (sz 8) woman - 7.-7.5mm (sz 7) (test balloon by filling with 10cc air) -stylet - placed in ETT for rigidity, bend it 30deg at proximal end
What can happens if cylinder N2O flow rate >4L/min?
may cause formation of frost on cylinder wall or freezing of the valve, owing to the loss of the latent heat of vaporization from the liquid N2O
Administration of which drugs are effective in suppressing local anesthetic-induced seizures
midazolam or diazepam
When performing video-assisted laryngoscopy with the GlideScope, the blade should be inserted _______, and as soon as the tip of the blade is past the ______, the operator should begin viewing the LCD monitor to identify the different airway structures and navigate to the glottic aperture.
midline teeth
If dead space increases, _________ must increase to maintain a constant PaCO2
minute ventilation (RR, Vt, or both)
What are the most and least potent anesthetic agents?
most = Isoflurane (OG coeff 99) least = N2O (OG coeff 1.4)
Lungs with low compliance are stiff lungs and will require ________ pressure to reach a given volume compared to lungs that have high compliance
much greater
Injection during an epidural blood patch should stop when the patient:
notes pressure in her back
When a magnet is placed on a newer generation ICD (PM + ICD), the magnet will...
only suspend shock therapy and it will not asynchronously pace the heart
Facial nerve monitoring generally involves stimulation of the temporal branch of the facial nerve that supplies the...?
orbicularis oculi muscle around the eye or the corrugator supercilii (most resistant) that moves the eyebrow when frowning (during stimulation eyelid and eyebrow movement)
How does succinylcholine work?
produces prolonged depolarization of the endplate region that results in desensitization of nicotinic acetylcholine receptors; inactivation of voltage-gated sodium channels at the neuromuscular junction; and increases in potassium permeability in the surrounding membrane. The end result is failure of action potential generation due to membrane hyperpolarization, and block ensues
Elderly have an ________ circulation time→ _______ induction time with inhalation , ________ induction time with IV drugs because of decreased Cardiac Output
prolonged increased slower
The short duration of action of succinylcholine is due to...?
rapid hydrolysis by butyrylcholinesterase (plasma cholinesterase) to succinylmonocholine and choline, such that only 10% of the administered drug reaches the neuromuscular junction
During TOF monitoring which sites are best for monitoring recovery and onset?
recovery = ulnar nerve onset = facial nerves
Elderly have ______ capacity to increase heart rate in response to hypotension, hypovolemia, and hypoxia
reduced
The most common cause of increased Vd/Vt ratio (dead space inc) under general anesthesia is a ___________. If the EtCO2 acutely decreases, you should first rule out ________ before considering other causes of increased dead space
reduction in cardiac output hypotension
A ventilator _______ ________ maintains circuit volume and pressure by releasing gas to the scavenger, in an amount equal to the fresh gas flow per minute.
relief valve (also known as the bellows pop-off valve, spill valve, or overflow valve)
________ is a synthetic opioid with a rapid onset and ultra-short duration, easily and rapidly metabolized by __________, with an elimination half-life of _______
remifentanil blood and tissue esterases (not cholinesterase enzyme, succs metabolism not affected) 8-20min (can cause hyperalgesia on d/c, cannot give neuraxially d/t glycine neurotox)
Classifications of breathing circuits (reservoir, rebreathing, example) Open
reservoir = no rebreathing = no examples = open, insufflation, nasal cannula or simple facemask
Classifications of breathing circuits (reservoir, rebreathing, example) Semi-open
reservoir = yes rebreathing = no examples = circle at high FGF (> min ventilation); or a non-rebreathing circuit
Classifications of breathing circuits (reservoir, rebreathing, example) Closed
reservoir = yes rebreathing = yes (complete) examples = circle at extremely low FGF, with adjustable pressure-limiting valve closed
Classifications of breathing circuits (reservoir, rebreathing, example) Semi-closed
reservoir = yes rebreathing = yes (partial) examples = circle at low FGF (< min ventilation)
In circle system if elevated inspired CO2 persist despite increasing the fresh gas flow, the...?
unidirectional valves are likely to be incompetent The operator should remove the expiratory valve (if possible), inspect and dry it, and then reassemble it (while ventilating the patient with an Ambu bag) if this cannot be done then a closed or semi-closed system should be converted to semi-open system
If fire is not extinguished on first attempt...If fire persists...
use a CO2 fire extinguisher activate fire alarm, evacuate patient, close OR door, and turn off gas supply to room
How does pulse oximetry work?
uses red and infrared light transmission to detect oxyhemoglobin
Laryngospasm is believed to occur as a result of sensory stimulation of the ______ nerve via the internal branch of the_____
vagus SLN
When an unexpected malignant hyperthermia crisis arises during a case, one follows a protocol including (as far as equipment is concerned)
withdrawal of triggering agents, stopping administration of volatile agents (& succinylcholine), hyperventilating with 100% oxygen, increasing FGF, change disposable breathing circuit and granules, activated charcoal
Mandibular protrusion test (ULBT)
• Class A: Patient can protrude the lower incisors anteriorly past the upper incisors and can bite the upper lip above the vermilion border (line where the lip meets the facial skin). • Class B: Patient can move the lower incisors in line with the upper incisors and bite the upper lip below the vermilion border, but cannot protrude lower incisors beyond. • Class C: Lower incisors cannot be moved in line with the upper incisors, and cannot bite the upper lip. (indicates difficult airway) -unreliable in edentulous, or as single assessment tool
Implications of large (>0.6L/kg) and small Vd (<0.4L/kg):
•A large Vd (>0.6L/kg) implies that drug is widely distributed and likely lipid soluble •A small Vd (<0.4L/kg) implies drug is largely contained in the plasma and likely water soluble
Hydromorphone dosing analgesic pca
•Analgesic -Adult 0.4-2 mg IV •PCA -Adult Demand 0.2-0.6 mg q5-15min -Adult Basal 0-0.2 mg/hr
Fentanyl dosing Intubation, postop, intrathecal, epidural, epidural with LA, PCA
•Intubation adjunct: 1-3 mcg/kg •Postop: 0.5-1.5 mcg/kg •Intrathecal: 10-25 mcg •Epidural: 10-100mcg, or mixed in local anesthetic 2-10mcg/ml •PCA: 10-20mcg q6-20min
In the treatment of postoperative pain, clinicians should avoid the neuraxial administration of:
•Magnesium •Benzodiazepines •Neostigmine •Tramadol •Ketamine
Poor pain control in the acute hospital setting can lead to many complications including:
•Pneumonia •deep vein thrombosis •infection, delayed healing •development of chronic pain •increase the average length of stay in the hospital •higher morbidity and mortality