Journal of cardiac surgery
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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 Ca2+ voltage gated channels) on the one hand and excessive activation of vasodilators (SIRS, iNOS, and low AVP) on the other. Use of angiotensin-converting enzyme inhibitor (ACE-I), calcium channel blockers, amiodarone, heparin, low cardiac reserve (EF < 35%), symptomatic congestive heart failure, and diabetes mellitus are the perioperative risk factors for VPS after cardiac surgery in adults. Till date, there is no consensus about the outcome-oriented therapeutic management of VPS. Vasopressors such as norepinephrine (NE; 0.025-0.2 µg/kg/min) and vasopressin (0.06 U/min or 6 U/h median dose) are the first choice for the treatment. The adjuvant therapy (hydrocortisone, calcium, vitamin C, and thiamine) and rescue therapy (methylene blue [MB] and hydroxocobalamin) are also considered when perfusion goals (meanarterial pressure [MAP] > 60-70 mmHg) are not achieved with nor-epinephrine and/or vasopressin. ⋯ Currently, the VPS is frequently encountered (9%-40%) in cardiac surgical patients with predisposing patient-specific risk factors and combined with inflammatory response to CPB. Multidrug therapy (NE, MB, AVP, ATII, terlipressin, hydroxocobalamin) targeting multiple receptor systems is recommended in refractory VPS. A combination of high dosage of ascorbic acid, hydrocortisone and thiamine has been used successfully as adjunctive therapyto restore the MAP. We also advocate for the early use of multiagent vasopressors therapy and catecholamine sparing adjunctive agents to restore the systemic perfusion pressure with a goal of preventing the progressive refractory VPS.