(1035) Adjunctive Methylene Blue Versus Hydroxocobalamin in Refractory Shock

Introduction: Refractory shock is characterized as persistent hypotension with end-organ dysfunction despite high-dose vasopressors. Although methylene blue (MB) and hydroxocobalamin (HXO) are commonly used as rescue treatments, large-scale head-to-head trials comparing these agents in refractory shock are lacking.

Methods: A multicenter retrospective study was conducted among patients who received adjunctive MB or HXO for refractory shock, defined as a requirement for norepinephrine equivalent (NEE) doses ≥ 0.2 mcg/kg/min to maintain a mean arterial pressure (MAP) ≥ 65 mmHg. The primary endpoint was the change in vasopressor requirements 24 hours after administration. Secondary endpoints included changes in MAP and vasopressor requirements over 24 hours (0, 6, 12, and 24 hours), time to vasopressor discontinuation, vasopressor-free days at 28 days, ICU and hospital length of stay, and hospital mortality.

Results: A total of 303 patients who received MB (n = 269) or HXO (n = 34) were included. The mean reduction in vasopressor requirements over 24 hours was similar, at 0.30 mcg/kg/min for MB compared to 0.27 mcg/kg/min for HXO (p = 0.381). The mean reduction in vasopressor requirements from baseline was significant in both groups at 6, 12, and 24 hours after administration (p < 0.001 each). In subgroup analyses, HXO was associated with a significantly larger reduction in vasopressor requirements over 24 hours among patients on mechanical circulatory support (0.40 vs 0.23 mcg/kg/min, p = 0.018). Additionally, patients who initially received 2 mg/kg of MB achieved a significantly larger reduction in vasopressor requirements than those who received fixed 50-100 mg or 1 mg/kg dosing (0.34 vs 0.21 vs 0.16 mg/kg/min, p < 0.001 and p = 0.016).

Conclusions: Both MB and HXO were effective in reducing vasopressor requirements over 24 hours among patients with refractory shock. Appropriate choice of agent and dosing regimen in specific patient populations may further improve clinical outcomes.