Methylene Blue for Vasoplegic Syndrome After Cardiac Operation: Early Administration Improves Survival

Abstract

Background: Vasoplegic syndrome, defined by hypotension despite normal or increased cardiac output, is associated with high mortality rate after cardiopulmonary bypass. Methylene blue (MB) is reported to ameliorate vasoplegic syndrome through the nitric oxide pathway. We hypothesized that early administration of MB would improve outcomes in patients with vasoplegic syndrome after cardiopulmonary bypass.

Methods: All patients that underwent cardiopulmonary bypass at our institution (Jan 1, 2011 to Jun 30, 2016) were identified through our Society of Thoracic Surgery database. Pharmacy records identified patients receiving MB within 72 hours of cardiopulmonary bypass. Multivariate logistic regression identified predictors of major adverse events among patients receiving MB.

Results: A total of 118 cardiopulmonary bypass patients (3.3%) received MB for vasoplegic syndrome. These patients had a higher incidence of comorbidities, and these cases were more commonly reoperative (76.1% versus 41.2%, p < 0.0001) and complex (70.3% versus 31.8%, p < 0.0001). The only difference in preoperative medications was that MB patients had a higher rate of amiodarone use (15.3% versus 2.2%, p < 0.0001). MB patients had significantly higher rates of postoperative complications, except atrial fibrillation. Early (operating room, 40.7%) versus late (intensive care unit, 59.3%) administration of MB was associated with significantly reduced operative mortality rate (10.4% versus 28.6%, p = 0.018) and risk-adjusted major adverse events (odd ratio 0.35, p = 0.037).

Conclusions: Operative mortality rate is high in patients receiving MB for the treatment of vasoplegia after cardiopulmonary bypass. Early administration of MB improves survival and reduces the risk-adjusted rate of major adverse events in these patients.