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Question 4#

Regarding preload, which of the following is true? 

A) It is approximated by the systemic vascular resistance which is calculated by dividing mean arterial pressure (MAP) by cardiac output
B) It is approximated by the right ventricular end-diastolic pressure (EDP) as estimated with pulmonary artery occlusion pressure
C) It is approximated by the right ventricular EDP as estimated with central venous pressure (CVP)
D) It is approximated by the left ventricular EDP as estimated with pulmonary artery occlusion pressure

Correct Answer is D

Comment:

For the right ventricle, central venous pressure (CVP) approximates right ventricular end-diastolic pressure (EDP). For the left ventricle, pulmonary artery occlusion pressure (PAOP), which is measured by transiently inflating a balloon at the end of a pressure-monitoring catheter positioned in a small branch of the pulmonary artery, approximates left ventricular EDP. The presence of atrioventricular valvular stenosis may alter this relationship. Left ventricular EDP is the most commonly used proxy for preload.