All of the following can contribute to low cardiac output after surgery EXCEPT:

Low cardiac output after surgery can be a significant concern and can arise from various physiological disturbances. Reduced preload due to fluid loss, cardiac tamponade, and postoperative arrhythmias are all recognized contributors to diminished cardiac output.

Reduced preload occurs when there is insufficient fluid volume in the circulation, which can be the result of either surgical fluid loss or inadequate fluid management. This directly affects the venous return to the heart, subsequent filling, and consequently leads to a decrease in stroke volume and cardiac output.

Cardiac tamponade is a condition where fluid accumulates in the pericardial space, exerting pressure on the heart. This prevents adequate filling of the heart chambers during diastole, hindering the heart’s ability to pump effectively, thereby decreasing cardiac output.

Postoperative arrhythmias can severely impact the heart’s efficiency, as they may lead to a loss of coordinated contraction and, in some cases, significantly reduced heart rate, both of which contribute to poor cardiac output.

In contrast, reduced afterload due to hypothermia does not lead to low cardiac output in the typical sense. Instead, hypothermia generally results in vasodilation and decreased systemic vascular resistance, which can, paradoxically, result in an increased cardiac output. The heart