A 75-year-old, 60-kg man with moderately disabling heart failure secondary to ischemic heart disease is undergoing a transurethral prostatic resection under halothane-nitrous oxide anesthesia. Resection time is 30 minutes, and fluid replacement has been lactated Ringer's solution 500 mL. Although heart rate is unchanged, the arterial pressure monitor used because of his cardiac condition has changed from A to B over the last 15 minutes. The most appropriate management is to
(A) discontinue halothane
(B) adminster ephedrine 10 mg intravenously
(C) administer digoxin one half of his daily dose intravenously
An elderly man has an acute dissection of the descending thoracic aorta. Which of the following antihypertensive therapies is most likely to extend the dissection?
(A) Esmolol infusion
(B) Nitroglycerin infusion
(C) Nitroprusside infusion
(D) Nitroprusside infusion combined with a beta-adrenergic blocker
A 60-year-old woman who is taking propranolol for hypertension and is allergic to penicillin is anesthetized with thiopental and halothane for resection of an abdominal aortic aneurysm. Shortly after intubation she is given vancomycin 500 mg intravenously, after which her blood pressure decreases from 140/80 to 70/50 mmHg while her heart rate remains steady at 64 bpm. The most likely explanation for the decrease in blood pressure is
(A) cross-sensitivity of penicillin and vancomycin
(B) interaction of vancomycin and propranolol
(C) vancomycin-induced anaphylactoid reaction
(D) interaction of halothane and propranolol
(E) interaction of halothane and vancomycin
C
A 38-year-old woman with B-positive blood requires immediate blood transfusion during abdominal hysterectomy. No B-positive blood is available; O-negative blood is used. Three minutes after starting transfusion of packed red blood cells, the patient develops tachycardia, bronchospasm, and hypotension. Which of the following is the most likely cause?
(A) Anaphylactic reaction to donor IgA
(B) Bacterial contamination of transfused blood
(C) Hemolysis resulting from ABO incompatibility
(D) Hypocalcemia
(E) IgG-mediated reaction to Rh antigens
A
In performing a diagnostic left lumbar sympathetic block for lower extremity claudication, the tip of the needle ideally should lie at point