Arterial pressure in the radial artery is 155/70 mmHg measured by a correctly calibrated catheter-transducer system. At the same time, aortic pressure is 140/75 mmHg using a high-fidelity catheter tip transducer. The most likely cause of this discrepancy is
(A) a large amount of air in the dome of the radial artery transducer
(B) coarctation of the aorta
(c) peripheral vascular constriction produced by sympathetic stimulation
(D) physiologic amplification of the waveform from the aorta to the radial artery
(E) too high a frequency response in the catheter-transducer system
Which of the following is most likely to occur during mediastinoscopy?
(A) Chylothorax
(B) Compression of the innominate artery
(C) Injury to the superior laryngeal nerve
(D) Tracheal tear
(E) Venous air embolism
B
A 65-year-old man undergoes prostatectomy in the lithotomy position under spinal anesthesia using bupivacaine 12 mg. Ten hours later, he reports that his left foot is numb. Examination shows decreased pinprick sensation over the lateral dorsal aspect of the left foot; dorsiflexion is limited. Which of the following is the most likely cause?
A 50-year-old patient is undergoing craniotomy for clipping of a cerebral aneurysm with isoflurane, nitrous oxide, and fentanyl anesthesia. At the time of aneurysm exposure, the EEG shows burst suppression. Which of the following is the most likely cause?
(A) causes more hemodynamic stimulation than an oropharyngeal airway
(B) is contraindicated in patients with cervical spine instability
(C) is more easily inserted when cricoid pressure is applied
(D) may serve as a temporary airway in case of a failed rapid sequence intubation
(E) requires administration of a muscle relaxant to avoid laryngospasm during insertion
D
An endobronchial Robertshaw tube is inserted for resection of a midesophageal tumor under isoflurane, oxygen, pancuronium anesthesia. Forty minutes into a planned two-hour resection, arterial blood gas values are reported as PO2 45 mmHg, PCO2 45 mmHg, and pH 7.33. Ten minutes earlier, the values were PO2 210 mmHg, PCO2, 41 mmHg, and pH 7.39. The first action should be to
(A) reposition the Robertshaw tube
(B) apply positive end-expiratory pressure to the ventilated lung
(C) reinflate and ventilate the non ventilated lung