question on myocardial oxygen supply

[yu-gi-oh]

Advertisement - Members don't see this ad

Need help with explanation of answer:

Which of the following is LEAST likely to decrease myocardial oxygen supply?

a. administration of volatile anesthetics
b. epidural anesthesia to sensory level of T6
c. increased pulmonary artery occlusion pressure
d. hypocarbia (PaCO2 25mmHg)
e. metabolic acidosis (pH 7.2)

answer e

 

[lvspro]

administration of volatile anesthetics - decreased aortic diastolic pressure (vasodilation)
epidural anesthesia to sensory level of T6 - decreased aortic diastolic pressure (vasodilation from sympathectomy)
increased pulmonary artery occlusion pressure - increased LV end diastolic pressure
hypocarbia (PaCO2 25mmHg) - causes coronary vaoconstriction
metabolic acidosis (pH 7.2) - causes coronary vasodilation

coronary perfusion pressure = aortic diastolic pressure - LV end diastolic pressure

Only metabolic acidosis increases myocardial O2 supply for sure. It's the best answer.

Agree. Coronary vasodilation, and alteration of Hg affinity for O2 (think O2 dissoc curve) means an increase in total O2 supply.