An axillary block is administered to a 60-kg patient using 40 ml of 0.5% bupivacaine. Ten minutes after placement of the block, the patient has a seizure. Which of the following statements is true?
(A) A low serum albumin concentration could have contributed to the occurrence of the seizure
(B) CNS hypoperfusion is the most likely cause of the seizure
(C) The seizure was probably secondary to an allergic reaction to the local anesthetic
(D) The use of an equipotent dose of lidocaine rather than bupivacaine would have decreased the likelihood of
Volume-cycled flow generators are preferred over pressure-cycled ventilators in critical care units because they
(A) have a lower compression volume
(B) limit peak airway pressure
(C) maintain constant ventilatory volume with changes in lung compliance
(D) more readily compensate for gas leaks
(E) permit more accurate measurement of the patient's minute volume
C
Measurement of mixed expired carbon dioxide concentration is necessary for the determination of
(A) dead space
(B) lung-thorax compliance
(C) physiologic shunt fraction
(D) diffusing capacity of the lungs
(E) ventilatory response to carbon dioxide
A
During postoperative indirect laryngoscopy, the vocal cords appear symmetric during quiet breathing and approximate to the left of midline during phonation. The most likely cause is
(A) pure abductor paralysis of the left cord
(B) pure abductor paralysis of the right cord
(C) abductor and adductor paralysis of the left cord
(D) abductor and adductor paralysis of the right cord
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
A 75-year-old man in the PACU complains of severe pain following thoracotomy. Respiratory rate is 30/min; arterial blood gas values are PaO2 70 mmHg, PaCO2 56 mmHg, and pH 7.28 at an FiO2 of 0.6. The patient has a thoracic epidural catheter and received epidural morphine 2 mg 45 minutes earlier. Which of the following is the most appropriate immediate management?
(A) Intravenous administration of naloxone
(B) Epidural administration of additional morphine
A patient undergoes differential spinal block for evaluation of persistent foot pain. If the pain returns coincident with a decrease in skin temperature, which of the following is the most appropriate conclusion?