The odor of isoflurane is noted during isoflurane anesthesia with an endotracheal tube and mechanical ventilation. Mean airway pressure is unchanged. A scavenging system with an open interface and an active disposal system is being used. The most likely cause of the isoflurane odor is
(A) a leak in the inspiratory limb of the anesthesia circuit
(B) application of excessive negative pressure to the scavenging interface
(C) malfunction of the pop-off valve of the anesthesia machine
(D) obstruction of the gas disposal tubing leading from the scavenging interface
(E) obstruction of the transfer tubing to the scavenging interface
D
Diplopia following lumbar puncture with a 25-gauge, 3 1/2-inch needle is the result of
(A) stretching the abducens nerve
(B) pressure on the optic nerve
(C) distortion of the oculomotor nucleus from collapse of the wall of the third ventricle
A 26-year-old patient with multiple trauma is admitted to the intensive care unit postoperatively. The early development of polyuria, hypotension, low urine sodium excretion, high serum osmolality, and normal serum creatinine concentration is best explained by
A middle-aged, 70-kg man with a brain tumor is scheduled for an elective craniotomy. Preoperatively, he is alert but papilledema is present. Anesthesia is induced with thiopental 300 mg and succinylcholine 100 mg, followed by tracheal intubation. Immediately following intubation vigorous bucking occurs. The best immediate management would be to
(A) administer succinylcholine 100 mg intravenously
(B) administer fentanyl 500 jug intravenously
(C) hyperventilate with isoflurane 2%
(D) administer thiopental 400 mg intravenously
(E) hyperventilate and administer lidocaine 1 mg/kg intravenously
A 2.2-kg, 6-hour-old neonate is to undergo gastrostomy followed by repair of a tracheoesophageal fistula. During induction with halothane, air, and oxygen, the abdomen becomes distended. Appropriate management is to
(A) intubate and assist spontaneous ventilation
(B) intubate and control ventilation
(C) insert an orogastric tube
(D) allow the patient to breathe spontaneously by mask until gastrostomy
A 55-year-old woman who is scheduled to undergo carotid endarterectomy has a history of essential hypertension and chronic obstructive pulmonary disease. Over a 30-minute period beginning one hour after induction of general anesthesia, Sp02 decreases from 99% to 95%. During that time, she has received fentanyl 100 mcg, isoflurane 1%, nitrous oxide 49.5%, oxygen 49.5%, and a nitroglycerin infusion to maintain blood pressure at approximately 160/95 mmHg. Which of the following is the most likely cause for the decline in oxygen saturation?
(A) Decreased cardiac output
(B) Increased dead space ventilation
(C) Inhibition of hypoxic pulmonary vasoconstriction