A patient whose trachea is intubated develops partial airway obstruction two hours after induction of fentanyl, nitrous oxide, oxygen anesthesia. The anesthesiologist discontinues the nitrous oxide and controls ventilation, and there is gradual improvement during the next hour. No evidence of a respiratory disorder is found at the conclusion of the anesthetic. Which of the following is most likely?
(A) The endotracheal tube was in the right mainstem bronchus
(B) The patient had an unrecognized air embolism
(C) The patient had a nitrous oxide pneumothorax
(D) The endotracheal tube cuff narrowed the airway
A 39-year-old patient with insulin-dependent diabetes mellitus receives thiopental 250 mg and succinylcholine 80 mg and is ventilated with 0.75% isoflurane in oxygen. Arterial pressure decreases abruptly from 140/100 to 80/50 mmHg while heart rate remains unchanged at 70 bpm. Failure of heart rate to increase most likely results from
(A) acute hypoglycemia
(B) autonomic neuropathy
(C) depression of sinus node function by thiopental
(D) depression of the baroreflex response by isoflurane
When treating reflex sympathetic dystrophy of an arm, which of the following is the best indicator of a successful sympathetic blockade?
(A) A pinprick sensory deficit in the distribution of C6
(B) A 5°C increase in the temperature of the skin of the hand
(C) An accentuated psychogalvanometric response in the forearm
(D) An ipsilateral positive Horner's syndrome
(E) Decreased temperature sensation in the hand
B
A patient with moderate hypothyroidism and unstable angina requires urgent coronary artery bypass grafting. Which of the following is most appropriate before proceeding with the operation?
(A) Initiation of epinephrine infusion
(B) Intramuscular administration of a barbiturate
(C) Intravenous administration of triiodothyronine (T3)
A 50-year-old woman notes loss of sensation in the medial lower leg 24 hours after vaginal hysterectomy in the lithotomy position. Which of the following nerves is most likely to be injured?