BCSE Principles of Anesthesia 2 — Questions and Answers
Question 1: Which volatile anesthetic has the lowest blood-gas partition coefficient, resulting in the fastest induction and emergence?
- Isoflurane
- Sevoflurane
- Desflurane (Correct answer)
- Halothane
Correct answer: Desflurane
Desflurane has the lowest blood-gas partition coefficient (0.42) among modern volatile agents, enabling the most rapid induction and emergence.
Question 2: A patient develops masseter muscle rigidity immediately after succinylcholine administration. What is the most concerning diagnosis?
- Normal fasciculation response
- Malignant hyperthermia susceptibility (Correct answer)
- Pseudocholinesterase deficiency
- Laryngospasm
Correct answer: Malignant hyperthermia susceptibility
Masseter spasm after succinylcholine is a warning sign of malignant hyperthermia susceptibility and warrants discontinuation of triggering agents.
Question 3: Which mechanism best describes how propofol produces its hypnotic effect?
- NMDA receptor antagonism
- GABA-A receptor potentiation (Correct answer)
- Opioid receptor agonism
- Alpha-2 adrenergic agonism
Correct answer: GABA-A receptor potentiation
Propofol enhances inhibitory chloride conductance through GABA-A receptor potentiation, producing sedation and hypnosis.
Question 4: During a difficult airway, which nerve block would anesthetize the supraglottic structures above the vocal cords?
- Recurrent laryngeal nerve block
- Superior laryngeal nerve internal branch block (Correct answer)
- Glossopharyngeal nerve block
- Hypoglossal nerve block
Correct answer: Superior laryngeal nerve internal branch block
The internal branch of the superior laryngeal nerve provides sensory innervation to the supraglottic larynx above the vocal cords.
Question 5: A patient receiving neuraxial anesthesia develops hypotension and bradycardia. Which spinal level has most likely been blocked?
- T10-T12
- T4-T6 (Correct answer)
- L1-L3
- S1-S4
Correct answer: T4-T6
Blockade of T4-T6 sympathetic fibers can block cardiac accelerator fibers, causing both hypotension from vasodilation and bradycardia.
Question 6: What is the primary advantage of using a laryngeal mask airway (LMA) over endotracheal intubation in appropriate cases?
- Provides superior protection against aspiration
- Requires less anesthetic depth to place (Correct answer)
- Enables positive pressure ventilation at higher pressures
- Eliminates the need for muscle relaxants
Correct answer: Requires less anesthetic depth to place
LMA placement requires less anesthetic depth and blunts hemodynamic responses less than laryngoscopy and intubation.
Question 7: Which pharmacokinetic model best describes the distribution of intravenous anesthetics after a bolus dose?
- One-compartment model
- Three-compartment model (Correct answer)
- Zero-order kinetics
- Michaelis-Menten kinetics
Correct answer: Three-compartment model
IV anesthetics are best described by a three-compartment model: central (plasma), rapidly equilibrating peripheral (vessel-rich tissues), and slowly equilibrating peripheral (muscle, fat).
BCSE Principles of Anesthesia 2
Which volatile anesthetic has the lowest blood-gas partition coefficient, resulting in the fastest induction and emergence?