Vasoplegic syndrome after cardiovascular surgery: A review of pathophysiology and outcome-oriented therapeutic management.

Background: Vasoplegic syndrome (VPS) is defined as systemic hypotension due to profound vasodilatation and loss of systemic vascular resistance (SVR), despite normal or increased cardiac index, and characterized by inadequate response to standard doses of vasopressors, and increased morbidity and mortality. It occurs in 9%-44% of cardiac surgery patients after cardiopulmonary bypass (CPB). The underlying pathophysiology following CPB consists of resistance to vasopressors (inactivation of Ca voltage gated channels) on the one hand and excessive activation of vasodilators (SIRS, iNOS, and low AVP) on the other.