Hydroxocobalamin or Methylene Blue for Vasoplegic Syndrome in Adult Cardiothoracic Surgery

Objective: To compare hydroxocobalamin and methylene blue for the treatment of vasopressor-refractory vasoplegic syndrome (VS) after adult cardiac surgery with cardiopulmonary bypass (CPB).

Design: A retrospective, propensity-matched, cohort study was performed. The primary endpoints were the percentage change in vasopressor use at 30, 60, and 120 minutes, characterized as both norepinephrine equivalents and vasoactive inotropic score. Eligible patients who received methylene blue were matched 3:1 with patients who received hydroxocobalamin based on sequential organ failure assessment score, preoperative mechanical circulatory support, CPB duration, and use of pre-CPB vasopressors, angiotensin-converting enzyme inhibitors, or beta-blockers.

Setting: A quaternary care academic medical center.

Participants: Adult patients who underwent cardiac surgery with CPB from July 2013 to June 2019.

Interventions: Patients were included who received either hydroxocobalamin (5,000 mg) or methylene blue (median 1.2 mg/kg) for VS in the operating room during the index surgery or in the intensive care unit up to 24 hours after CPB separation.

Measurements and main results: Of the 142 included patients, 120 received methylene blue and 22 received hydroxocobalamin. After matching, 66 patients in the methylene blue group were included in the analysis. Baseline demographics, surgical characteristics, and vasoactive medications were similar between groups. There were no significant between-group differences in percentage change in norepinephrine equivalents or vasoactive inotropic score at each timepoint.

Conclusions: In adult patients undergoing cardiothoracic surgery using CPB with VS, the ability to reduce vasopressor use was similar with hydroxocobalamin compared with methylene blue.