Association of Methylene Blue Dosing With Hemodynamic Response for the Treatment of Vasoplegia

Objectives: To compare the hemodynamic response of methylene blue dosing regimens (bolus v bolus plus infusion) for the treatment of vasoplegia.

Design: A retrospective cohort analysis.

Setting: A single-center academic medical center.

Participants: Patients who underwent cardiac surgery at Cleveland Clinic and received methylene blue between 2016 and 2019. Patients were excluded from the analysis if methylene blue was initiated >48 hours after surgery, if the cardiac index was <2.0 L/min/m², or if they returned to the operating room for postoperative hemorrhage.

Interventions: Methylene blue bolus-only regimens versus bolus plus continuous infusion methylene blue regimens.

Measurements and main results: The primary outcome was vasopressor requirement over 48 hours (1, 3, 6, 12, 24, and 48 hours) after methylene blue initiation. Other hemodynamic outcomes evaluated included the rate of methylene blue response, mean arterial pressure (MAP), and systemic vascular resistance (SVR) values over time. In total, 44 patients were included in the analysis, 33 of whom only received a methylene blue bolus. Vasopressor requirements at baseline were 95 (95% CI: 70-122) µg/min norepinephrine equivalent (NE) in the bolus-only group and 100 (86-130) µg/min in the infusion group. Vasopressor requirements decreased at each time point in both groups and were similar throughout (hour 1 mean [95% CI] NE, bolus 79 [67-91] µg/min v bolus plus infusion 84 [63-104] µg/min; p = 0.71). MAP, SVR, and rates of methylene blue response were similar between groups at all time points. Clinical outcomes also were similar between groups.

Conclusions: The addition of a methylene blue continuous infusion did not significantly improve hemodynamic response. Bolus-only dosing of methylene blue may be sufficient for the treatment of vasoplegia after cardiac surgery.