A 157 cm (5 ft 2 in), 180-kg, 40-year-old woman has a PaO2 of 65 mmHg, a PaCO2 of 38 mmHg, and a pH of 7.43 while breathing room air preoperatively. The most likely cause of these values is
(A) decreased hypoxic ventilatory drive
(B) higher than normal oxygen extraction from blood
(C) lower than normal cardiac output
(D) lower than normal functional residual capacity
Forty-eight hours after thoracotomy, a patient's T6-7 epidural catheter is removed and the distal 2 cm is noted to be missing. The patient felt no pain during removal and neurologic examination shows no abnormalities. After informing the patient, which of the following is the most appropriate next step in management?
Volume-cycled flow generators are preferred over pressure-cycled ventilators in critical care units because they
(A) have a lower compression volume
(B) limit peak airway pressure
(C) maintain constant ventilatory volume with changes in lung compliance
(D) more readily compensate for gas leaks
(E) permit more accurate measurement of the patient's minute volume
C
A sedative/hypnotic drug is administered prior to electroconvulsive therapy to do which of the following?
(A) Potentiate the effect of succinylcholine
(B) Provide amnesia for the electrical stimulus
(C) Decrease the current required to produce a grand mal seizure
(D) Increase seizure duration
(E) Control postictal sympathetic response
B
You are called to a witnessed cardiac arrest where cardiopulmonary resuscitation is being performed. After successful intubation, arterial blood gas values are PaO2 86 mmHg, PaCO2 63 mmHg, and pH 7.25 at an FiO2 of 1.0. The most appropriate management at this time is to
(A) repeat arterial blood gas analysis using a new specimen
(B) administer sodium bicarbonate
(C) administer fluid challenge with 500 ml of normal saline solution
During pulmonary artery catheterization, a 65-year-old man receives morphine 6 mg and scopolamine 0.4 mg intravenously. The pulse oximeter indicates desaturation, which quickly resolves with stimulation. When the drapes are removed, he has unilateral eye pain, decreased visual acuity, and dilated and irregular pupils. These eye symptoms are most likely caused by