American Board of Surgery Qualifying Exam (ABS QE) Practice Test

In distributive shock, what would you expect the systemic vascular resistance (SVR) to be?

1. High

2. Normal

3. Low

4. Variable

The correct answer is: Low

Distributive shock is characterized by a significant decrease in systemic vascular resistance (SVR). This condition arises from widespread vasodilation, which can occur in various scenarios such as septic shock, neurogenic shock, or anaphylactic shock. When vasodilation occurs, the blood vessels become more relaxed and dilated, resulting in lower resistance to blood flow. As a consequence of this reduced resistance, the SVR is notably low. This low SVR is one of the hallmark features of distributive shock and is often accompanied by normal or elevated cardiac output as the heart attempts to compensate for the decreased perfusion pressure caused by the vasodilation. In contrast, in states like hypovolemic or cardiogenic shock, one would typically observe elevated SVR due to compensatory mechanisms that attempt to maintain blood pressure and perfusion to vital organs. Thus, understanding that distributive shock leads to a decreased SVR is crucial in recognizing and managing this type of shock effectively.