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
A 70-year-old man has a pacemaker set at VOO mode at 70 bpm with temporary atrial and ventricular wires placed prior to separation from cardiopulmonary bypass. Fifteen minutes after separation, he develops atrial fibrillation with a ventricular response of 80 to 100 bpm. Which of the following ECG findings is most likely?
(A) Irregular atrial and ventricular complexes with loss of pacer artifacts
(B) Irregular ventricular complexes with preserved ventricular pacer artifacts at 70 bpm
(C) Occasional pacer artifacts when intrinsic ventricular rate is slower than 70 bpm
(D) Regular ventricular complexes at 70 bpm
(E) Ventricular complexes with preserved atrial and ventricular pacer artifacts at 70 bpm
B
A 40-year-old man is undergoing open reduction and internal fixation of a fractured femur. During anesthesia with fentanyl, sevoflurane, and oxygen, heart rate decreases to 20 bpm and 6 premature ventricular contractions per minute are noted. No pulse is detected. The most appropriate next step is to
A 72-year-old patient who takes levodopa and carbidopa is undergoing colon resection. Metoclopramide is administered preoperatively and anesthesia is maintained with proposal, fentanyl, and nitrous oxide, with vecuronium for muscle relaxation. Fifteen minutes after reversal of muscle relaxation with neostigmine and atropine and tracheal extubation, the patient has dyspnea and muscular rigidity. Which of the following is the most likely cause?
(A) Central anticholinergic syndrome
(B) Fentanyl-induced rigidity
(C) Inhibition of methionine synthetase by nitrous oxide