Cardiac Medicine Certification (CMC) Practice Exam

What effect does hypovolemia generally have in the context of acute heart failure?

1. Increases oncotic pressure

2. Causes vasodilation

3. Prevents fluid retention

4. Increases blood volume

The correct answer is: Causes vasodilation

In the context of acute heart failure, hypovolemia refers to a decrease in the volume of blood in the body, which affects the hemodynamic status of the patient. When blood volume is low, the body typically responds through compensatory mechanisms that include hormone release such as renin, leading to the activation of the renin-angiotensin-aldosterone system (RAAS). This system plays a critical role in regulating blood pressure and fluid balance. One of the outcomes of hypovolemia is vasodilation, which can occur due to several factors. In response to low blood volume, the body may experience a decrease in venous return to the heart, causing the heart to respond by trying to reduce systemic vascular resistance to maintain cardiac output. This vasodilation can lead to further complications in acute heart failure, as the already compromised heart struggles to maintain adequate perfusion to vital organs. The other options do not correctly reflect the physiological response to hypovolemia in cases of acute heart failure. While hypovolemia can influence oncotic pressure, it does not typically increase it, and instead, it can lead to decreased oncotic pressure due to reduced plasma proteins. Moreover, hypovolemia often leads to increased fluid