American Association of Critical-Care Nurses (AACN) Certification Practice Test

What physiological change is typically seen with hypovolemic shock?

1. Increased cardiac output (CO)

2. Increased pulmonary capillary wedge pressure (PCWP)

3. Decreased central venous pressure (CVP)

4. Decreased peripheral vascular resistance (PVR)

The correct answer is: Decreased central venous pressure (CVP)

In hypovolemic shock, the body experiences a significant loss of blood volume, which is often due to factors such as hemorrhage or dehydration. This loss of volume leads to several physiological changes as the body attempts to compensate and maintain adequate circulation and perfusion to vital organs. One key change is the decrease in central venous pressure (CVP). CVP is a measure of the pressure in the thoracic vena cava, reflecting the volume of blood returning to the heart. In hypovolemic shock, as blood volume is reduced, there is less venous return to the heart, which directly results in lower pressures in the thoracic venous system. Therefore, a decrease in CVP is consistent with the body trying to compensate for the reduced intravascular volume. In contrast, the other options reflect physiological responses that do not typically align with the state of hypovolemic shock. For example, an increase in cardiac output would generally indicate better volume status and cardiac function, which is contrary to what occurs in hypovolemic shock. Similarly, an increased pulmonary capillary wedge pressure indicates fluid overload or increased left atrial pressure, which is not characteristic of a condition where volume is critically low. Lastly, decreased peripheral vascular resistance is