A 65-kg 70-year-old man in the PACU is breathing spontaneously at 20/min through an endotracheal tube connected to a T-piece with a fresh gas flow of 5 L/min. He has a tidal volume of 350 mL and an FiO2 of 0.5. SpO2 decreases from 98% to 84% over one hour, then improves to 92% with an FiO2 of 1.0. Which of the following is the most likely cause of the hypoxemia?
During anesthesia with nitrous oxide 65% in oxygen, fentanyl, and pancuronium, nitroprusside is administered to decrease arterial pressure to 85/50 mmHg. A decrease in PaO2 from 120 to 65 mmHg is most likely caused by
A rapid shallow ventilatory pattern is most energy efficient for a patient who
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 patient with lumbar disk disease requires lumbar epidural injection of a corticosteroid for control of low back pain. Which of the following statements concerning this treatment is true?
Two days after total abdominal hysterectomy, a 54-year-old woman develops lethargy followed by seizures and coma. Laboratory studies show a serum sodium concentration of 108 mEq/L and serum osmolality of 225 mOsm/kg. The most appropriate next step in management is administration of which of the following?
Properly performed local anesthetic block of the celiac plexus
A 48-year-old woman underwent a posterior fossa craniotomy in the sitting position. Monitoring included precordial Doppler, arterial blood pressure, central venous pressure (CVP), and urine output. Furosemide was used intraopera-tively for cerebral decompression, and the operation was uneventful. In the recovery room, she was awake with stable vital signs when the CVP suddenly increased from 6 to 25 mmHg without any change in blood pressure. Shortly thereafter, premature ventricular contractions are noted. After administering lidocaine 1 mg/kg intravenously, the most appropriate action is to
Initiation of positive pressure mechanical ventilation is LEAST likely to decrease cardiac output in patients with which of the following conditions?
Four hours after open cholecystectomy, a patient who is breathing spontaneously has an SpO2 of 93% in the supine position and an SpO2 of 98% when placed in the head-up position. The most likely cause of this change is an increase in which of the following?