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
In an anesthetized patient being mechanically ventilated, end-expired carbon dioxide is 58 mmHg and peak inspiratory airway pressure is 15 cmH20. Ventilator settings indicate a delivered tidal volume of 800 ml, but the expiratory flowmeter shows a tidal volume of 360 ml. Which of the following is the most likely cause of this discrepancy?
(A) Fresh gas flow of 0.5 L/min
(B) Incompetence of the pressure-relief valve
(C) Low ventilatory rate
(D) Presence of a hole in the ventilator bellows
(E) Prolongation of the inspiratory phase
B
Which of the following is the most appropriate treatment of methemoglobinemia prior to emergency surgery?
A 45-year-old woman with mitral stenosis is scheduled for elective mitral valve replacement. Two minutes after tracheal intubation, she develops atrial fibrillation with a ventricular response rate of 150 bpm and a decrease in blood pressure to 75/45 mmHg. Which of the following is the most appropriate first step in management?
(A) Increasing the concentration of enflurane
(B) Increasing the infusion rate of lactated Ringer's solution
(C) Intravenous administration of digoxin
(D) Intravenous administration of propranolol
(E) Electrical cardioversion
E
A 64-year-old man with a large pancreatic tumor has severe abdominal pain that radiates to the low back. Which of the following is the most appropriate management?
(A) Bilateral LI rhizotomy
(B) Dorsal column stimulation
(C) Hypogastric plexus block
(D) Neurolytic celiac plexus block
(E) Patient-controlled analgesia
D
The mortality rate of patients given drug A is 12% (8 of 66) and the mortality rate of patients given drug B is 15% (10 of 66). Which of the following tests is most appropriate to compare these mortality rates?
Which of the following is characteristic of low back pain associated with myofascial pain syndrome but not of pain associated with a herniated lumbar disk?
(A) Loss of reflexes in the lower extremities
(B) Pain along the distribution of nerve roots
(C) Responsiveness to epidural corticosteroids
(D) Sensitivity to injection at trigger points
(E) Trophic alteration in the sympathetic nervous system