ABA Anesthesia Principles & Practices 3 — Questions and Answers
Question 1: In a patient receiving a remifentanil infusion for total intravenous anesthesia (TIVA), the MOST important consideration at emergence is:
- Transition to longer-acting analgesia before stopping infusion (Correct answer)
- Stopping propofol 30 minutes before remifentanil
- Reversing remifentanil with naloxone routinely
- Continuing remifentanil at a reduced rate in recovery
Correct answer: Transition to longer-acting analgesia before stopping infusion
Remifentanil's ultra-short half-life causes acute opioid offset; without bridging analgesia, patients awaken in severe pain.
Question 2: A patient develops masseter muscle rigidity after succinylcholine administration. The MOST appropriate immediate action is:
- Proceed cautiously, monitor for signs of malignant hyperthermia (Correct answer)
- Administer dantrolene empirically and cancel the case
- Switch immediately to rocuronium and continue the case
- Perform arterial blood gas and wait for results before deciding
Correct answer: Proceed cautiously, monitor for signs of malignant hyperthermia
Isolated masseter spasm after succinylcholine may be a normal variant or early MH sign; vigilant monitoring for tachycardia, hypercapnia, and temperature rise guides management.
Question 3: The volume of distribution (Vd) of a drug is MOST influenced by:
- Degree of tissue and plasma protein binding (Correct answer)
- Hepatic extraction ratio
- Renal clearance rate
- Bioavailability after oral dosing
Correct answer: Degree of tissue and plasma protein binding
Vd reflects how extensively a drug distributes into tissues versus remaining in plasma, heavily dependent on both tissue and plasma protein binding.
Question 4: Which patient population has the GREATEST increase in sensitivity to non-depolarizing neuromuscular blocking agents?
- Patients with myasthenia gravis (Correct answer)
- Patients with burns covering >50% BSA
- Patients with denervation injuries
- Patients with hepatic failure
Correct answer: Patients with myasthenia gravis
Myasthenia gravis reduces functional acetylcholine receptors at the NMJ, so far fewer receptors need blocking to achieve neuromuscular block.
Question 5: Cerebral autoregulation maintains constant cerebral blood flow over a MAP range of approximately:
- 50–150 mmHg (Correct answer)
- 20–80 mmHg
- 60–200 mmHg
- 70–130 mmHg
Correct answer: 50–150 mmHg
In neurologically intact adults, cerebral autoregulation maintains CBF across MAPs of roughly 50–150 mmHg; outside this range, CBF becomes pressure-passive.
Question 6: Which pharmacokinetic model BEST describes the behavior of propofol during prolonged infusion?
- Three-compartment model with redistribution from deep peripheral compartment (Correct answer)
- One-compartment model with first-order elimination
- Two-compartment model without peripheral redistribution
- Zero-order elimination model at clinical doses
Correct answer: Three-compartment model with redistribution from deep peripheral compartment
Propofol distributes into central, rapidly-equilibrating, and slowly-equilibrating (deep peripheral) compartments; prolonged infusion saturates deep compartments, prolonging recovery.
Question 7: The primary mechanism by which volatile anesthetics produce bronchodilation is:
- Direct smooth muscle relaxation via reduced intracellular calcium (Correct answer)
- Beta-2 adrenergic receptor stimulation
- Anticholinergic blockade of muscarinic M3 receptors
- Inhibition of mast cell histamine release
Correct answer: Direct smooth muscle relaxation via reduced intracellular calcium
Volatile anesthetics relax airway smooth muscle primarily by decreasing intracellular calcium availability and reducing calcium sensitivity of contractile proteins.
ABA Anesthesia Principles & Practices 3
In a patient receiving a remifentanil infusion for total intravenous anesthesia (TIVA), the MOST important consideration at emergence is: