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

What indicates a decrease in cardiac output in cardiogenic shock?

1. Increased central venous pressure (CVP)

2. Increased systemic vascular resistance

3. Decreased pulmonary capillary wedge pressure (PCWP)

4. Increased stroke volume

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

A decrease in cardiac output in cardiogenic shock is indicated by increased central venous pressure (CVP). In cardiogenic shock, the heart's ability to pump effectively is compromised, leading to reduced blood flow and perfusion to organs. This inefficiency causes blood to back up in the veins, resulting in an elevation of the CVP. As the heart struggles to maintain adequate circulation, the pressure in the central veins rises because of the increased volume of blood returning to the heart without sufficient pumping action to expel it. Elevated CVP can also reflect fluid overload as a consequence of decreased cardiac output and compensatory mechanisms activated by the body. In contrast, an increase in systemic vascular resistance typically occurs as a response to low cardiac output; however, it does not directly indicate a decrease in output. Similarly, decreased pulmonary capillary wedge pressure (PCWP) would suggest better left atrial filling and function, which is not characteristic of cardiogenic shock. Increased stroke volume, on the other hand, would indicate good heart function, as it shows the heart's ability to eject a larger volume of blood per contraction.