Answer to Question 1
ANS: C
A. Incorrect response: See explanation C.
B. Incorrect response: See explanation C.
C. Correct response: Succinylcholine, a depolarizing neuromuscular blocking agent, has an extremely rapid onset of 30 to 90 seconds and a short duration ranging from 3 to 5 minutes, making it an ideal NMBA for emergency use.
Burn patients tend to have increased potassium released into the extracellular fluid compartment. However, succinylcholine can exacerbate that problem by causing further release of intracellular potassium into the extracellular space. The induced hyperkalemia can cause cardiac dysrhythmias and cardiac arrest. Alternatively, the nondepolarizing neuromuscular blocking agent rocuronium establishes neuromuscular blockade within 2 minutes, and seems to be favored during emergencies and for purposes such as endotracheal intubation.
D. Incorrect response: See explanation C.
Answer to Question 2
ANS: A
A. Correct response: In patients with renal disease, caution is warranted in the use of aminosteroids (pancuronium, vecuronium, and rocuronium) because clearance can be greatly reduced and duration prolonged. Similar caution for this class is indicated in patients with cirrhosis. Vecuronium, a benzylisoquinoliniu m, has been reported to be the most associated with prolonged duration of action after discontinuation and should be avoided in these patients. Atracurium and cisatracurium are preferred agents in these patients because their clearance is not affected by real or hepatic dysfunction.
B. Incorrect response: Atracurium is preferred in this case.
C. Incorrect response: Vecuronium is contraindicated in this situation.
D. Incorrect response: Aminosteroids are not advisable for patients with liver and/or renal disease.