A patient receives remifentanil 25 mcg just before retrobulbar block with 0.25% bupivacaine 4 mL. Over the next 10 minutes, he develops apnea and loses consciousness. Which of the following is the most likely explanation?
(A) Effects of remifentanil
(B) Injection of local anesthetic into cerebrospinal fluid
Two hours after coronary artery bypass grafting, a 60-year-old man has a heart rate of 140 bpm and blood pressure of 80/60 mmHg. Cardiac index is 1.5 L/min/m2. Central venous pressure is 23 mmHg with large a-waves in the right atrial pressure tracing. A pulsus paradoxus of 6 mmHg is noted. Which of the following is the most likely diagnosis?
A 76-year-old man has a leaking abdominal aortic aneurysm. His blood pressure and pulse have remained stable for 15 minutes at 90/60 mmHg and 130 bpm, respectively. His hemoglobin concentration is 11 g/dl, and the EKG shows a left bundle branch block. Induction of anesthesia should proceed
(A) after a pulmonary artery catheter has been inserted and the pulmonary artery occlusion pressure is greater than 7 mmHg
(B) when the pulse has decreased below 130 bpm from the rapid transfusion of blood
(C) when systolic blood pressure has increased to more than 120 mmHg from the rapid infusion of lactated Ringer's solution
(D) immediately on arrival in the operating room
(E) when circulatory signs deteriorate or cease to improve with rapid volume expansion
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
(A) position the patient head down, right side up and aspirate the CVP catheter
(B) withdraw the CVP catheter 5 cm
(C) infuse potassium chloride rapidly
(D) administer furosemide
(E) ask the neurosurgeon to reevaluate the patient immediately
Which of the following should be included in the preoperative management of a 12-year-old patient with Duchenne's muscular dystrophy who is unable to ambulate?
(A) Determination of serum creatine kinase concentration
(B) Determination of serum potassium concentration
A 25-year-old woman is admitted to the hospital in the early stages of labor at term. Initial hematocrit is 33%. Which of the following is the most likely cause of the hematocrit value?