NBCRNA Review

What are the two pathological variants of the nicotinic receptor?

1) episilon replaced by gamma subunit 2) 5 alpha subunits

Key side effects of kappa receptor stimulation

dysphoria, antishivering, diuresis

What drug noncompetitively inhibits acetylcholinesterase?

echothiophate/organophosphates

What drug inhibits acetylcholinesterase via electrostatic attachment?

edrophonium

Which beta-blocker can significantly decrease the amount of propofol required to prevent patient movement upon skin incision?

esmolol

What drugs are metabolized by nonspecific esterases?

esmolol, remifentanil, atracurium (+ hoffman), etomidate (+ liver)

What is the primary pathway of etomidate metabolism?

ester hydrolysis driven by plasma esterases and microsomal enzymes

What drugs must be avoided with acute intermittent poryphyrias?

etomidate, barbiturates, glucocorticoids, hydralazine

Treatment for acute intermittent poryphyrias

glucose and heme arginate

What are some examples of common enzyme inhibitors that decrease clearance of drugs?

grapefruit juice, cimetidine, omeprazole, SSRIs, isoniazid, erythromycin

What is unique about pancuronium?

has vagolytic properties making it good for bradycardia or regurgitant lesions

The Mu-2 receptor is primarily responsible for producing what side effects?

respiratory depression, physical dependence, and constipation

What muscarinic antagonist causes the most sedation?

scopolamine

Monoamine oxidase primarily serves to inactivate what through oxidative deamination?

serotonin, dopamine, epinephrine, norepinephrine

What drugs are metabolized by pseudocholinesterase?

succinylcholine, mivacurium, ester local anesthetics

What NMBs cause release of histamine?

sux, atracurium, mivacurium

A propofol syringe must be discarded when? infusion?

syringe = 6 hours infusion = 12 hours

pyridostigmine vs edrophonium dose

pyridostigmine = 0.3 mg/kg edrophonium = 1 mg/kg

The dose for IV or IM midazolam is __________ mg/kg

0.02-0.04

Rocuronium ED95

0.3 mg/kg

Its difficult to detect visual or tactile fade when the TOF > ____

0.4

Maximum dose of cocaine when used as a local anesthetic in adults

150-200 mg

vapor pressure of sevoflurane

157 mmHg

What are the five subunits on the nicotinic receptor?

2 alpha, 1 beta, 1 delta, 1 epsilon

EMLA cream components

2.5% lidocaine and 2.5% prilocaine

Approximately what portion of the total amount of body water is intracellular?

2/3rds

pulmonary HTN is defined as a mean PAP of ______ mmHg

25

Heterozygous deficiency is defined as a dibucaine number between ____-_____

30-70

PDE-___ inhibitors are useful for pulmonary HTN

5

What characteristic places the elderly at increased risk of 30 day mortality?

ASA physical status 4

What is Sampter's triad?

Asthma, nasal polyps and allergy to aspirin (aspirin exacerbated respiratory disease)

What causes fade during train of four stimulation?

antagonism of presynaptic Nn receptors

Pyridostigmine crosses the BBB making it useful for treating central anticholinergic syndrome. T or F

False, physostigmine crosses BBB (useful for anticholinergic syndrome)

With atypical plasma cholinesterase, pseudocholinesterase is not produced in sufficient quantities and will prolong the duration of action for succinylcholine. T or F

False, pseudocholinesterase is produced in sufficient quanities but the enzyme that is produced is not functional

Propofol induction dose should be based on ideal body weight for an obese patient. T or F

False, should be based on lean body weight

Opioids decrease the incidence of myalgias. T or F

False. pretreatment 1/10 dose of nondepolarizer, NSAIDs, lidocaine, and a higher dose of sux reduce the risk.

what drugs are in class I antiarrhythmics?

IA = quinidine, procainamide HCl, disopyramide IB = lidocaine, mexilitine HCl, tocainide, phenytoin IC = flecainide acetate, propafenone HCl

How much is MAC reduced in the full term parturient?

MAC is decreased by 40%

Why are patients with egg allergy probably safe to administer propofol too, despite lecithin being a component of propofol?

Most people are allergic to the egg white proteins. Lecithin is found in egg yolk, soy, and peanuts (the latter two have their allergy proteins removed during the refinement process)

triggers of sickle cell crisis

Pain Hypothermia Acidosis Dehydration

What PIA is not metabolized to TFA?

Sevoflurane not metabolized to TFA, but is broken down to inorganic fluoride ions

A patient undergoing inhalation induction of anesthesia has a severe ventilation-perfusion defect. The speed of induction would be affected the most with what PIA: nitrous oxide, desflurane, isoflurane, or sevoflurane?

The effect is greatest in agents with a low blood:gas partition coefficient. Will effect N2O the most. The effect may be more visible in nitrous oxide than in desflurane despite the difference in blood:gas partition coefficients because of the extremely high concentrations of nitrous oxide normally used compared to that of desflurane.

In patients with scoliosis, what is the strongest predictor of need for postoperative ventilation

VC less than 40% of predicted

Body mass % of the four tissue groups

VRG 10% Muscle/skin 50% Fat 20% Vessel poor group 20%

Cardiac output % to the four tissue groups

VRG 75% Muscle/skin 20% Fat 5% Vessel poor group <1%

How can you calculate loading dose?

Vd x (desired plasma concentration/bioavailability)

TURP absorbed volume per minute vs blood loss per minute

absorbed 10-30 ml/min blood loss 2-5 ml/min

Lidocaine affects what phase of the action potential to serve as an antiarrhythmic?

affects phase 0 (influx of Na)

How long should N2O be avoided with air bubble, silicone oil, sulfur hexafluoride?

air bubble = 5 days silicone oil = 0 days Sulfur hexafluoride = 10 days

opioid potency compared to 10 mg morphine (alfentanil, fentanyl, remifentanil, sufentanil, ketorolac, meperidine, hydromorphone)

alfentanil = 1 mg fentanyl = 100 mcg remifentanil = 100 mcg sufentanil = 10 mcg ketorolac = 30 mg meperidine = 100 mg hydromorphone = 1.5 mg

What opioid has the fastest onset and why?

alfentanil has the fastest onset because it mainly exists in nonionized form (90%) and has a small volume of distribution

Volume of distribution calculation

amount of drug/desired plasma concentration

What is the major intracellular anion? cation?

anion = phosphate cation = potassium

Basic vs acidic drugs protein binding

basic = alpha 1 glycoprotein acidic = albumin

What are the three components of a local anesthetic molecule?

benzene ring, intermediate chain (ester vs amide), tertiary amine

What local anesthetics can cause methemoglobinemia?

benzocaine, cetacaine (contains benzocaine), prilocaine, EMLA cream (contains prilocaine)

Which term refers to the amount of the drug that is able to reach its target receptor after it is introduced into the circulatory system?

bioavailability

The Mu-1 receptor is primarily responsible for producing what side effects?

bradycardia, urinary retention, miosis

What diseases increase the risk of MH?

central core, minicore, and king-denborough syndome

When placed properly, where does the tip of an LMA lie?

cricopharyngeus muscle (upper esophageal sphincter)

Etomidate may cause a slight decrease in BP due to what?

decrease in SVR

How do multiple sclerosis affect depolarizers vs nondepolarizers

depolarizers = hyperkalemia nondepolarizers = sensitive

Which PIA is most associated with a transient increase in liver enzyme levels?

desflurane

What electrolyte disturbance can affect MAC?

hyponatremia = decreases MAC hypernatremia = increases MAC

What drugs are useful to treat pulmonary HTN?

iloprost, epoprostenol, PDE-V inhibitors (sildenafil), endothelin 1 antagonists (bosentan), inhaled nitric oxide

A low time constant will increase or decrease the rate of rise of FA/FI

increase rate of rise (faster onset)

Patients with hemophilia A will have what coagulation lab abnormalities?

increased PTT

What electrolyte disturbances potentiate neuromuscular blocking agents? (lithium, magnesium, calcium, potassium)

increased lithium, increased magnesium, decreased calcium, decreased potassium

Signs of cyanide toxicity with nitroprusside use

increased mixed venous O2, increased nitroprusside dosage requirements (tachyphylaxis), and metabolic acidosis.

Why do nondepolarizers cause a phase II block?

inhibit the presynaptic nicotinic receptor Ach mobilization is impaired

Which body fluid normally has a higher concentration of protein?

intracellular fluid

How many fluoride atoms are located on desflurane, isoflurane, and sevoflurane

isoflurane = 5 desflurane = 6 sevoflurane = 7

A right to left shunt will slow an inhalation induction with what PIA the least (N2O, Des, Iso, Sevo) and why?

isoflurane effected the least since it has a high solubility (more uptake in blood which partially offsets the dilution effect)

Which organ is primarily responsible for excreting opioids and their metabolites?

kidneys

calculation for therapeutic index

lethal dose 50 / effective dose 50

max dosages of local anesthetics

lidocaine/mepivacaine = 4 mg/kg or 7 mg/kg with epi bupivacaine/ropivacaine = 2 mg/kg or 3 mg/kg with epi 2CP = 15 mg/kg or 20 mg/kg with epi

What benzo is the most potent amnestic?

lorazepam

What 3 common drugs are used to increase uterine tone and what are their side effects?

methergine is ergot derivative - avoid in hypertensive pts carboprost is a PGE2 - avoid in reactive airway disease oxytocin = can cause hypotension/tachycardia with rapid administration

What PIAs are methyl isopropyl ethers? methyl ethyl ethers?

methyl isopropyl ether = sevoflurane methyl ethyl ether = isoflurane and desflurane

What drugs reduce pseudocholinesterase activity?

metoclopramide, esmolol, neostigmine, echothiophate, oral contraceptives, MAO inhibitors, cyclophosphamide, nitrogen mustard

What primary cause of hypoxemia is unlikely to respond to increases in FiO2?

pulmonary edema (right to left shunt)

What are the endogenous ligands of mu, kappa, and delta receptors?

mu = endorphins kappa = dynorphins delta = enkephalins

What muscarinic receptor causes bradycardia?

muscarinic 2 receptor

What neuromuscular disease causes a resistance to sux

myasthenia gravis

examples of nongap vs gap metabolic acidosis

nongap - diarrhea, renal tubular necrosis, excessive NaCl administration gap - lactic acidosis, ketoacidosis, renal failure

best place to measure onset of blockade (intubation conditions) vs recovery of blockade (return of upper airway muscle function)

onset = orbicularis oculi or corrugator supercilii (facial nerve) return = adductor policis (ulnar nerve) or flexor hallucis

Opioid receptor MOA

opioid binds to receptor, activates G protein, adenylate cyclase is inhibited, cAMP is inhibited, Ca conductance is decreased, K conductance is increased

Which Phase 1 reaction is characterized by reactions that remove electrons from a molecule?

oxidation

What NMB is long-acting?

pancuronium (85 min duration)

The study of the intrinsic responsiveness of the body to a drug is known as ___________

pharmacodynamics

What term refers to the dose of a drug required to produce a given effect in 50 percent of subjects?

potency

What local anesthetic is metabolized to O-toluidine?

prilocaine

Rank IV anesthetics from most to least plasma protein binding

propofol, midazolam, dexmedetomidine, etomidate, ketamine

What are some examples of common enzyme inducers that increase clearance of drugs?

tobacco, ethanol, phenytoin, barbiturates, rifampin

What TEE view is best used for monitoring the filling and contractile function of the LV?

transgastric short view

Studies have shown that C fibers (which are unmyelinated and transmit pain and temperature impulses) are more resistant to blockade than A-delta fibers and B fibers. T or F?

true

What subunits must be occupied to open the nicotinic receptor at the motor end plate?

two alpha subunits

Risk of mendelson syndrome when aspirate volume and pH is what?

volume over 25 cc and pH less than 3

LA's exist as weak (acids or bases) with a (positively or negatively) charged amine group

weak bases and positively charged amine group

Who is at highest risk of myalgias after sux administration?

young adults undergoing ambulatory surgery (women>men)