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

Which condition is associated with increased cardiac output (CO)?

1. Hemorrhagic shock

2. Cardiogenic shock

3. Septic shock

4. Neurogenic shock

The correct answer is: Septic shock

In septic shock, there is often an initial increase in cardiac output due to the body's response to infection and systemic inflammation. This condition is characterized by the release of inflammatory mediators that cause vasodilation and increased heart rate, ultimately leading to increased cardiac output. The body's compensatory mechanisms in septic shock aim to maintain tissue perfusion despite systemic vasodilation; thus, the heart works harder. This is contrasted with other types of shock. For instance, in hemorrhagic shock and cardiogenic shock, there is a decrease in cardiac output due to reduced blood volume or impaired cardiac contractility, respectively. Neurogenic shock also leads to decreased cardiac output due to loss of sympathetic tone and resultant vasodilation. Therefore, the unique response of the cardiovascular system in septic shock makes it the condition associated with increased cardiac output.