Rosh Emergency Medicine Practice Test

In patients with cardiovascular compromise, which parameter is commonly decreased?

1. Cardiac output

2. Blood pressure

3. Heart rate

4. Pulmonary capillary wedge pressure

The correct answer is: Cardiac output

In the context of cardiovascular compromise, a decrease in cardiac output is a key finding. Cardiac output refers to the volume of blood the heart pumps per minute, and it is critically important for maintaining adequate tissue perfusion and oxygenation. When a patient experiences cardiovascular compromise—due to conditions such as heart failure, severe hypovolemia, or cardiogenic shock—the heart's ability to generate an adequate cardiac output diminishes. This reduction can occur due to weakened myocardial contractility, impaired filling of the heart, or increased resistance to blood flow, leading to less effective circulation. As a result, vital organs may not receive sufficient blood flow, contributing to the patient's instability. While blood pressure can also be affected in cases of cardiovascular compromise, it is not solely indicative of cardiac output. Blood pressure can be maintained through peripheral vasoconstriction mechanisms even if cardiac output is low. Heart rate might increase in response to decreased cardiac output as a compensatory mechanism but does not reflect a decrease. Pulmonary capillary wedge pressure, which can indicate left atrial pressure, may also be altered; however, it is not a direct measure of cardiac output itself and can be influenced by multiple factors. Overall, recognizing the decrease in cardiac output is essential in managing