The increased resistance of severely burned patients to pancuronium is primarily due to
(A) enhanced urinary excretion of pancuronium
(B) decreased number of presynaptic cholinergic receptors
(C) increased number of postsynaptic cholinergic receptors
(D) increased rate of metabolism of pancuronium
(E) increased volume of distribution of pancuronium
C
A 60-kg, 70-year-old man requires open reduction and internal fixation of an intertrochanteric fracture sustained 24 hours ago. Serum creatinine concentration is 1 mg/dl and blood urea nitrogen concentration is 40 mg/dl. The most likely cause of these findings is
A 62-year-old man, who had a myocardial infarction three years ago, complicated by congestive heart failure and renal failure, is undergoing a colectomy. A pulmonary artery catheter demonstrates a cardiac output higher than measurements recorded during a cardiac catheterization two months after the infarction. Which of the following most likely contributes to the increased cardiac output?
(A) Creation of an arteriovenous fistula
(B) Increased hemoglobin concentration from 10 to 12 g/dl
(C) Stimulation of carotid body receptors
(D) Transcutaneous nitroglycerin
(E) Use of a beta-adrenergic blocker to prevent myocardial reinfarction
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
An 18-year-old patient with hemophilia A is scheduled for inguinal hernia repair. Preoperatively, factor VIII concentration is 60% of normal. The most appropriate management is administration of
(A) fresh frozen plasma
(B) cryoprecipitate
(C) factor VIII concentrate
(D) vitamin K
(E) none of the above
E
A 62-year-old woman with polycythemia vera is scheduled to undergo total knee arthroplasty using a tourniquet. Preoperative hematocrit is 60%. Which of the following is the most appropriate action?
(A) Perform total knee arthroplasty without use of a tourniquet
(B) Preoperative reduction of the hematocrit to 45% to 50%
(C) Prophylactic administration of aprotonin during surgery
(D) Prophylactic administration of epsilon-aminocaproic acid during surgery
(E) Prophylactic administration of low-dose heparin during surgery
B
A 50-year-old patient is undergoing middle ear exploration with isoflurane, nitrous oxide, and oxygen anesthesia. Ventilation is controlled; PetC02 is 35 mmHg, heart rate is 90 bpm, and blood pressure is 120/70 mmHg. Assistance is needed to minimize bleeding in the surgical field. Which of the following is the most appropriate next step in management?
(A) Addition of 5 cmH20 positive end-expiratory pressure
(B) Changing the anesthetic agent to halothane
(C) Hyperventilation to a PetC02 of 20 mmHg
(D) Placing the patient in reverse Trendelenburg position
(E) Titration of nitroprusside to a mean arterial pressure of 55 mmHg