During cardiopulmonary bypass, the perfusionist notes that the mixed venous oxygen saturation has decreased from to 55%. Which of the following is the most likely cause?
(A) Administration of a nitroprusside bolus
(B) Administration of a thiopental bolus
(C) Decrease in rectal temperature from 34°C to 28°C
A patient is undergoing a craniotomy in the sitting position. Mean arterial pressure measures 80 mmHg from a radial artery catheter located 27 cm below the right atrium and a transducer located, zeroed, and calibrated at the level of the right atrium. The circle of Willis is 27 cm above the right atrium. Intracranial pressure is 0 cmH20 and right atrial pressure is 5 cmH20. The cerebral perfusion pressure in mmHg is
(A) 75
(B) 60
(C) 53
(D) 48
(E) 26
B
Each of the following factors decreases uterine blood flow EXCEPT
Administration of succinylcholine 1 mg/kg to a pregnant woman rarely causes fetal neuromuscular blockade. Which characteristic of succinylcholine best explains this phenomenon?