Certified Pediatric Emergency Nurse (CPEN) Practice Exam

Which type of shock is characterized by relative hypovolemia?

1. Septic shock

2. Cariogenic shock

3. Hypovolemic shock

4. Distributive shock

The correct answer is: Distributive shock

Relative hypovolemia is a key characteristic of distributive shock. In this type of shock, there is an abnormal distribution of blood volume due to vasodilation, which leads to a significant drop in systemic vascular resistance. This results in inadequate blood flow and oxygen delivery to tissues despite normal or increased total blood volume. In septic shock, for example, systemic inflammatory response leads to widespread vasodilation and increased capillary permeability, causing fluid to leak into the interstitial space. This can create a scenario where there is enough blood volume overall but the effective circulating volume is diminished due to the peripheral vasodilation. While hypovolemic shock is due to a loss of fluid volume, either from hemorrhage or dehydration, and cardiogenic shock is related to the heart's failure to pump effectively, they do not involve the concept of relative hypovolemia in the same way distributive shock does. Thus, recognizing the distinct mechanism that underpins distributive shock is crucial for understanding its classification regarding hypovolemia.