Methylene blue for vasodilatory shock in the intensive care unit: a retrospective, observational study

Abstract

Abstract Background Refractory vasodilatory shock is a state of uncontrolled vasodilation associated with underlying inflammation and endothelial dysregulation. Rescue therapy for vasoplegia refractory to catecholamines includes methylene blue (MB) which restores vascular tone. We hypothesized that (1) at least 40% of critically ill patients would respond positively to MB administration and (2) that those who responded to MB would have a survival benefit. Methods This study was a retrospective review that included all adult patients admitted to an intensive care unit treated with MB for the indication of refractory vasodilatory shock. Responders to MB were identified as those with a ≥ 10% increase in mean arterial pressure (MAP) within the first 1-2 hours after administration. We examined the association of mortality to the groups of responders versus non-responders to MB. A subgroup analysis in patients undergoing continuous renal replacement therapy (CRRT) was also performed. Statistical calculations were performed in Microsoft Excel® (Redmond, WA, USA). Where appropriate, the comparison of averages and standard deviations of demographics, dosing, MAP, and reductions in vasopressor dosing were performed via Chi squared, Fisher's exact test, or two-tailed t-test with a p-value 10%. Patients supported with CRRT who were identified as responders had decreased ICU mortality compared to non-responders.

Keywords

• Methylene blue
• Nitric oxide synthase inhibitors
• Vasoplegia
• Vasodilatory shock
• Vasopressor sparing