A 66-year-old man with aortic regurgitation is brought to the operating room for aortic valve replacement after having received morphine, scopolamine premedication. PO2 is 40 mmHg in a sample of pulmonary artery blood drawn 10 minutes after the patient started breathing pure oxygen. This finding is compatible with
A 75-year-old man is confused, restless, and disoriented two days after an aortic aneurysm repair. Serum sodium concentration is 112 mEq/L, serum osmolality is low, and urine is hypertonic. The most appropriate treatment is
(A) restriction of fluid intake
(B) administration of isotonic saline solution
(C) administration of hypertonic (3%) saline solution
(D) administration of spironolactone
(E) infusion of mannitol 25 g
C
At extubation performed one week after nasotracheal intubation, each of the following is likely to occur EXCEPT
During frontal craniotomy for removal of an astrocytoma, the surgeon notes that the brain is "tight." The patient is receiving nitrous oxide 50% in oxygen, isoflurane 0.5%, fentanyl, and pancuronium. Heart rate is 92 bpm, blood pressure is 110/60 mmHg, end-tidal carbon dioxide tension is 31 mmHg, and oxygen saturation is 98%. The most appropriate initial treatment is to
(A) administer a beta-adrenergic blocker
(B) administer thiopental
(C) decrease isoflurane concentration
(D) decrease mean arterial pressure to 60 mmHg
(E) increase alveolar ventilation
E
A pulmonary artery catheter is placed in an awake patient breathing room air. Typical right ventricular and pulmonary artery pressure tracings are obtained. With the catheter balloon inflated, blood drawn from the distal port has a PaO2 of 100 mmHg, while a simultaneous radial artery sample has a PaO2 of 90 mmHg. These data indicate that the