What complication could cause persistent hypotension in a post-operative CABG patient despite treatment with fluids and an alpha agonist?

Vasoplegia is a condition characterized by vasodilation and reduced systemic vascular resistance, which can lead to persistent hypotension. In the context of a post-operative CABG patient, this can occur as a result of the surgical procedures and the ensuing inflammatory response, causing the blood vessels to relax excessively. Even when treated with fluids and alpha agonists—medications that are intended to constrict blood vessels and increase blood pressure—the effectiveness can be diminished in the presence of vasoplegia, leading to continued hypotension.

In post-operative settings, particularly after cardiac surgery, vasoplegia can be influenced by factors including the use of cardiopulmonary bypass, the release of inflammatory mediators, and changes in the autonomic nervous system. These factors can overwhelm the compensatory mechanisms of vasoconstriction, leading to challenges in restoring adequate blood pressure despite aggressive fluid resuscitation and medication therapy.

Other complications, like acute kidney injury or acute saphenous vein graft closure, while they may have their own impacts on blood pressure and hemodynamics, would typically not solely cause the persistent hypotension situation described in this context. ARDS, although critical and life-threatening, relates more to respiratory function rather than direct vascular tone and systemic vascular resistance