During a craniotomy for a supratentorial tumor, a 28-year-old man receives isoflurane 0.75% in nitrous oxide 70% and oxygen. Ventilation is controlled to maintain PaCO2 at 25 mmHg. Nasopharyngeal temperature is 35.8°C. While the dura mater is open, the surgeon complains that the brain is bulging. The most appropriate management at this time is to
(A) decrease the inspired isoflurane concentration to 0.5%
(B) hyperventilate further to decrease PaCO2 to 20 mmHg
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
An obese, 70-year-old woman with a long history of tobacco abuse is awake and semirecumbent after uneventful anesthesia with isoflurane for a ventral hernia repair. During the first hour in the recovery room while breathing 50% oxygen by face mask, her arterial oxygen saturation decreases to 90% while other vital signs remain satisfactory. Which of the following is most likely to be effective in the management of this situation?
A 33-year-old primigravid woman with myasthenia gravis, well-controlled with pyridostigmine, is in labor with the cervix dilated 7 cm. She has a headache and feels very nervous. Blood pressure is 160/115 mmHg, she has 3+ pitting edema, and urinalysis shows 4+ protein. Appropriate management of her labor should include
(A) lumbar epidural block with bupivacaine 8 ml of 0.5% solution
A 33-year-old woman is scheduled for emergency appendectomy under general anesthesia. She has hypertrophic cardiomyopathy and has had two episodes of syncope in the past year. Which of the following statements concerning anesthetic management is true?
(A) Spinal anesthesia is preferred to general anesthesia
(B) Deep levels of isoflurane anesthesia are appropriate
(C) Fluid administration should be restricted
(D) Phenylephrine is preferred to ephedrine to treat hypotension
(E) Positive end-expiratory pressure will decrease left ventricular outflow obstruction
During carotid endarterectomy, which of the following EEG patterns is most suggestive of cerebral ischemia?
(A) Ipsilateral spike-and-wave activity
(B) Bilateral change from beta to alpha rhythm
(C) Ipsilateral increase in beta activity
(D) Ipsilateral decrease in the spectral edge frequency from 10 to 4 Hz
(E) Bilateral increase in the spectral edge frequency from 8 to 15 Hz
D
A 50-year-old patient undergoes subtotal thyroidectomy for Graves' disease. In the immediate postoperative period, he has marked hoarseness but no stridor. The most likely cause of the hoarseness is trauma to the
(A) external branch of the superior laryngeal nerve
(B) internal branch of the superior laryngeal nerve