An otherwise healthy 16-year-old girl is undergoing posterior spinal fusion for thoracolumbar scoliosis. During the procedure, the most likely cause of a marked decrease in the amplitude of the somatosensory evoked potentials after stimulation of the posterior tibial nerve is
(A) administration of fentanyl 30 jag /kg for induction
(B) administration of isoflurane 1.3 MAC for maintenance
(C) administration of vecuronium 0.15 mg/kg
(D) a decrease in body temperature from 37 to 35°C
A 20-year-old man with a history of substance abuse is undergoing preoperative evaluation. Which of the following findings suggests current use of cocaine?
An adult patient with atrial fibrillation develops pulseless ventricular tachycardia wfiile undergoing synchronized electirical cardioversion. Which of the following is the most appropriate management?
(A) Intravenous administration of adenosine
(B) Intravenous administration of a bolus of lidocaine followed by electrical cardioversion
(C) Immediate repeat synchronized cardioversion at the same energy level
(D) Immediate repeat synchronized cardioversion at twice the previous energy level