A patient with cardiogenic shock has an IABP inserted. Which of the following reveals a desired response to therapy?

• A. Increased heart rate
• B. Increased pulmonary capillary wedge pressure
• C. Decrease systemic vascular resistance
• D. Worsening renal function

Answer: (C)

Reducing the heart’s workload by lowering afterload is what the intra-aortic balloon pump is meant to do in cardiogenic shock. The balloon inflates during diastole to improve coronary perfusion and then deflates just before systole, which lowers aortic pressure the ventricle has to pump against. This relief from high afterload shows up as a decrease in systemic vascular resistance, signaling that the heart can eject more easily and forward flow increases. That improved forward flow tends to lower left-sided filling pressures and boost perfusion to organs, including the kidneys. In contrast, a higher heart rate can be a sign of compensation but doesn’t necessarily reflect a beneficial response to IABP; rising pulmonary capillary wedge pressure indicates worse left-sided pressures, and worsening renal function signals inadequate perfusion.