If cardiac output decreases but systemic vascular resistance increases, what could this indicate?

• A. Sepsis
• B. Pulmonary embolism
• C. Congestive heart failure
• D. Cardiogenic shock

Answer: (B)

In the context of cardiovascular physiology, a decrease in cardiac output alongside an increase in systemic vascular resistance often indicates that the body is attempting to compensate for decreased blood flow due to a primary issue.

Pulmonary embolism can lead to a reduction in cardiac output, as a clot in the pulmonary arteries restricts blood flow to the lungs, meaning less oxygenated blood returns to the heart for systemic circulation. In an effort to maintain blood pressure and perfusion to vital organs, systemic vascular resistance can increase due to compensatory mechanisms such as vasoconstriction. The body raises systemic vascular resistance to counteract the drop in cardiac output, which may lead to increased afterload and can eventually exacerbate strain on the heart.

In contrast, conditions such as sepsis typically present with decreased systemic vascular resistance due to widespread vasodilation, congestive heart failure might show a decrease in cardiac output but generally with variable resistance based on compensatory factors, and cardiogenic shock often presents with low output and can result in altered resistance depending on the nature of the heart failure. Thus, the combination of decreased cardiac output with increased systemic vascular resistance is more indicative of a scenario like pulmonary embolism.