Fundamentals & Core Concepts Flashcards

The bispectral index (BIS) monitor measures which physiologic parameter to assess depth of anesthesia?

Answer: Processed EEG waveform analysis

BIS uses a proprietary algorithm to process raw EEG data into a dimensionless number (0-100) that correlates with level of consciousness and anesthetic depth.

Neostigmine reversal of neuromuscular blockade should always be accompanied by an anticholinergic agent because neostigmine:

Answer: Inhibits acetylcholinesterase, causing muscarinic side effects like bradycardia and increased secretions

Neostigmine inhibits acetylcholinesterase at all cholinergic synapses (both nicotinic and muscarinic), so muscarinic antagonists like glycopyrrolate are coadministered to prevent bradycardia and hypersalivation.

Which factor primarily determines the duration of action of a single bolus dose of local anesthetic?

Answer: Protein binding

Protein binding determines duration of local anesthetic action; agents with higher protein binding (bupivacaine, ropivacaine) dissociate slowly from sodium channels and have prolonged duration.

A patient develops ST-segment depression, hypertension, and tachycardia intraoperatively. The MOST appropriate initial intervention is:

Answer: Deepen anesthesia and consider beta-blocker or nitroglycerin

ST depression with hypertension and tachycardia suggests myocardial ischemia from increased oxygen demand; deepening anesthesia reduces sympathetic tone, and beta-blockers or nitroglycerin address the underlying supply-demand mismatch.

The Bezold-Jarisch reflex, which can occur during spinal anesthesia, causes:

Answer: Bradycardia, hypotension, and vasodilation

The Bezold-Jarisch reflex is a paradoxical vagal reflex triggered by decreased venous return to the heart, causing bradycardia, hypotension, and systemic vasodilation.

Which statement about nitrous oxide (N2O) is CORRECT?

Answer: It can expand closed gas-filled spaces by replacing nitrogen

N2O (blood:gas coefficient 0.47) diffuses rapidly into compliant, gas-filled cavities (bowel, pneumothorax, middle ear) because it replaces nitrogen, which leaves the space much more slowly.

Which class of drugs is used as the antidote for benzodiazepine overdose during procedural sedation?

Answer: Flumazenil (competitive benzodiazepine antagonist)

Flumazenil competitively antagonizes benzodiazepines at the GABA-A receptor's benzodiazepine binding site, rapidly reversing sedation and respiratory depression.