What factor can contribute to postoperative vasodilation leading to hypotension after cardiac surgery?

Postoperative vasodilation leading to hypotension after cardiac surgery can indeed be attributed to both rewarming post-surgery and the inflammatory response resulting from cardiopulmonary bypass (CPB). During CPB, the body is subjected to a number of factors that can trigger an inflammatory response, including exposure to foreign surfaces of the CPB circuit and manipulation of blood components. This response can lead to the release of pro-inflammatory cytokines, which may cause widespread vasodilation.

Rewarming is also a critical factor in this context. When patients are cooled during CPB to reduce metabolic demand, they may experience vasodilation upon rewarming as normal thermoregulatory processes kick in. Warmed blood returning to the body can induce vasodilation and lead to a drop in systemic vascular resistance, contributing to hypotension.

Together, these elements illustrate how both the inflammatory response due to CPB and the physiological changes associated with rewarming can synergistically lead to hypotension in the postoperative phase, making this answer the most comprehensive one regarding postoperative vasodilation. The understanding of these mechanisms is crucial for managing patients effectively after cardiac surgery.