Drugs—ITE Flashcards
Reduced cardiac output has what effect on inhalational induction? Which gases are most affected?
Reduced cardiac output promotes a faster rate of induction. This is especially true with soluble volatiles.
Solubility of volatiles is based on blood-gas coefficients. Is a volatile with low blood gas coefficient more or less soluble? List the gases from least to most soluble.
Low blood gas coefficient is less soluble.
Des < nitrous < sevo < iso < halothane
Which volatile anesthetic undergoes the most extensive metabolism?
Sevoflurane. Despite elevations in serum fluoride in long cases, it has not been shown to cause fluoride induced nephrotoxicity.
By what mechanism do volatiles potentiate neuromuscular blockade?
Volatiles potentiate NMB by decreasing the sensitivity of the post-junctional membrane to depolarization, increasing skeletal mm blood flow, and depressing upper motor neurons.
Volatile anesthetics are thought to cause an uncoupling effect. What does this mean?
They decrease CMRO2 while increasing CBF via a direct vasodilatory effect.
When a patient is administered 75% NO, the gas will rapidly diffuse from the blood into air filled cavities. How long does is take a pneumothorax to double in size with nitrous? To triple?
A PTX will double in 10m and triple in 30m
Effect of L to R intracardiac shunt on inhalational induction speed? IV induction speed?
No effect on either
R to L intracardiac shunt effect on inhalational induction speed? IV induction speed?
Decreased inhalational induction speed
Increased IV induction speed
Effect of intrapulmonary shunt on inhalational induction speed? IV induction speed?
Decreased speed of inhalational induction
No effect on IV induction speed
Factors decreasing MAC
Hyponatremia Hypothermia Hypoxia Older age Metabolic acidosis Anemia hgb Pregnancy Acute EtOH use Chronic methamphetamine use Hypercarbia
Factors increasing MAC
Red hair Acute methamphetamine use Chronic etoh use Cocaine Young age Hypernatremia Hyperthermia Ephedrine Levodopa MAOIs
Metabolic effects of epinephrine
—Hyperglycemia (increased gluconeogenesis, increased glycogenolysis, decreased insulin)
—increased free fatty acids
—hypokalemia
Which volatile most significantly augments neuromuscular blockade?
Desflurane
Glycopyrrolate MOA
Muscarinic anticholinergic in the periphery
Neostigmine MOA
Anticholinesterase
Side effects of anticholinesterase
Bradycardia, hypotension, bronchospasm, secretions, miosis, decreased intraocular pressure
The onset of effect of local anesthetic is affected by what 4 factors?
- Concentration (higher is faster)
- Lipid solubility (higher is faster)
- pKa (lower is faster; more unionized at physiologic pH)
- Environmental pH (higher is faster; more basic)
Physiologic changes associated with bicarbonate administration
Increased preload Decreased contractility Increased hgb affinity for oxygen Increased lactate *can cause intracranial hemorrhage
Which opioid receptor does naloxone bind to most strongly?
Mu
What is the preferred method of beta blockade in pts with reactive airway disease?
Beta 1 selective antagonists because they do not cause bronchoconstriction or vasoconstriction s/t sparing of beta 2 antagonism.
List the ester local anesthetics
Procaine
Chlorprocaine
Tetracaine
(Preservatives Can Taint)
Propofol should be used within what time frame of opening a vial?
12 hrs
Terbutaline MOA and SFx
MOA: beta 2 agonist
SFx: hyperglycemia, tachycardia, hypokalemia
Clopidogrel is a prodrug activated by what enzyme?
Cyp450
Beta-1 selective blockers
Atenolol Bisoprolol Esmolol Acebutolol Metoprolol
Non selective beta blockers
Carvedilol Timolol Labetalol Nadolol Propranolol Pindolol
Careful, This Lot’s Nor Particularly Picky
Active metabolite of meperidine and SFX
The active metabolite of meperidine is normeperidine and it causes seizure activity.
Metabolites of morphine and their SFX
Primary active metabolite is M6G, it is 100x more potent than morphine, and accumulation causes respiratory depression.
Inactive metabolite is M3G and causes myoclonus and allodynia
What is the best induction agent for pts with hypovolemic trauma at no risk for elevated ICP?
Ketamine
Lithium effect on NMBDs
Prolongs action if NDNMBDs and depolarizing NMBDs
What percent of platelet function is restored when an irreversible platelet inhibitor is held for one day?
10-15%
Aspirin MOA
Blocks the formation of thromboxane A2 in platelets which prevents platelet aggregation.
Succinylcholine effect on lower esophageal sphincter tone and on intragastric pressure
Increases both
Which inhalational agent is associated with megaloblastic hematologic changes?
Nitrous oxide
NO inhibits the vitamin B12-dependent enzymes methionine synthetase and thymidylate synthetase. Usually sub clinical effects in healthy pts but can cause neurologic and hematologic sequelae in critically ill and B12 deficient pts
List the volatile anesthetics in order of NDNMB potentiation. Where does propofol fall on this spectrum?
Des>sevo>iso>halothane>propofol
Treatment for delirium associated with scopolamine
Physostigmine
List commonly tested medications that cause pain on injection
Prop Roc Etomidate Diazepam Methohexital
List commonly tested medications that are not associated with pain on injection
Midazolam Opioids Ketamine Dexmedetomidine Fospropofol
herbal supplements associated with increased risk of bleeding
Ginger, garlic, ginkgo, vitamin E
Most common side effects of fospropofol
Parenthesias (general and perianal) and pruritis
Chlorprocaine’s rapid onset of action is secondary to what characteristic of the drug?
Concentration
Name the 4 potassium soaring diuretics
Spironolactone
Eplerenone
Amiloride
Triamterene
all can be associated with hyperkalemia
Nicardipine metabolism and excretion
Metabolized by liver
Excreted by kidneys
By what mechanism does etomidate cause adrenal suppression?
Inhibition of 11 beta hydroxylase
