A woman with chronic obstructive pulmonary disease is extubated and minimally responsive after isoflurane anesthesia. She is receiving oxygen 6 L/min through a face mask. Respirations are 10/min, PaO2 is 68 mmHg, PaCO2 is 54 mmHg, and pH is 7.28. The most likely cause of the respiratory acidemia is
(A) blunted sensitivity to low pH in the medullary respiratory center
(B) chronic carbon dioxide retention
(C) decreased lung volume from supine positioning
(D) depression of carotid body chemoreceptors by halothane
(E) suppression of hypoxic ventilatory drive by supplemental oxygen
Immediately after a retrobulbar block for cataract surgery, the eye grossly protrudes and the patient has the sensation of pressure in the eye. The most appropriate initial intervention is
Preoperative evaluation shows a serum sodium concentration of 140 mEq/L, serum chloride concentration of 90 mEq/L, PaCO2 of 46 mmHg, and arterial pH of 7.50. These findings are most indicative of prior treatment with
A 64-year-old man with diabetes mellitus well controlled with NPH insulin undergoes lower extremity revascularization. Following administration of protamine 10 mg, the patient has facial flushing and blood pressure of 60/30 mmHg. The most appropriate initial step in management is administration of which of the following drugs?