To summarize the evidence of the hemodynamic effects and vasopressor requirements of adult cardiac surgery patients with vasoplegic shock treated with hydroxocobalamin or methylene blue.

Systematic review and meta-analysis.

Multi-institutional.

Adult cardiac surgery patients with vasoplegic shock.

Administration of hydroxocobalamin or methylene blue.

A total of 263 patients in four retrospective observational studies were included in a pooled analysis. There was no significant difference in the primary outcome, vasopressor requirement at 1 hour (mean difference [MD]: 0.00 mcg/kg/min norepinephrine equivalent [NEE], 95% confidence interval [CI]: –0.09 to 0.08). Hydroxocobalamin was associated with a significant improvement in mean arterial pressure at 1 hour (MD: 5.30 mmHg, 95% CI: 2.98 to 7.62), total vasopressor dose at 1 hour (MD: –0.13 mcg/kg/min NEE, 95% CI: –0.25 to –0.01), total vasopressor at 6 hours (MD: –0.15 mcg/kg/min NEE, 95% CI: –0.21 to –0.08). No differences were observed in systemic vascular resistance or mortality between groups. Three studies were deemed at moderate risk of bias and one at serious risk.

Hydroxocobalamin has been shown to have a beneficial effect on hemodynamics and vasopressor requirements in vasoplegic cardiac surgery patients compared with methylene blue, although evidence is limited, and further well-powered randomized controlled trials are required.