A 60-year-old man undergoing resection of an abdominal aortic aneurysm has an increase in measured mixed venous oxygen saturation from 70% to 90%. Which of the following is the most likely cause?
(A) Decreased cardiac output
(B) Decreased hematocrit
(C) Intrapulmonary shunting
(D) Right to left shunting at the atrial level
(E) Wedging of the pulmonary artery catheter
E
During active labor, 10 ml of bupivacaine 0.5% with epinephrine 1:200,000 is administered epidurally. Fifteen minutes later, maternal blood pressure is 70/50 mmHg and heart rate is 70 bpm; fetal heart rate is 90 bpm for 45 seconds, with loss of beat-to-beat variability. The most likely explanation for the fetal vital signs is
A patient receives 1.5% bupivacaine 40 ml and epinephrine 1:200,000 for axillary brachial plexus block for reduction of a forearm fracture. The tourniquet is inflated to 300 mmHg; 45 minutes later, the patient has pain that radiates to the posteromedial elbow. Which of the following nerves is NOT adequately blocked?
Phantom limb pain is an example of which of the following types of pain?
(A) Central pain
(B) Nociceptive pain
(C) Psychosomatic pain
(D) Sympathetically mediated pain
(E) Vasospastic pain
A
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 wave form from the aorta to the radial artery
(E) too high a frequency response in the catheter-transducer system