Early Use of Methylene Blue in Refractory Shock: A Retrospective Experience from a Cardiac ICU

Abstract

Objectives: This study aimed to evaluate the hemodynamic effects and clinical outcomes associated with early administration of methylene blue in patients with refractory shock admitted to a tertiary cardiac intensive care unit. Methodology: This retrospective comparative cohort study included adult patients with refractory shock requiring vasopressor support. Patients who received methylene blue were compared with an equal-sized consecutively selected control group who did not receive MB. Primary study variables included changes in vasopressor requirements, Vasopressor-Inotrope Score (VIS), and MAP/VIS+1 ratio. Secondary outcomes included ICU mortality, duration of mechanical ventilation, length of ICU stay, and markers of end-organ dysfunction. Results: A total of 26 patients were analyzed (13 MB, 13 controls). Early MB administration was associated with a significant reduction in norepinephrine dose within 24 hours (p=0.035), decreased FiOâ‚‚ requirement (p=0.019), and a markedly shorter duration of norepinephrine infusion (p=0.004). Improvement in VIS trends and MAP/VIS+1 ratio was observed following MB administration. However, no statistically significant differences were found in ICU mortality (p=0.431), duration of mechanical ventilation (p=0.801), or ICU length of ICU stay (p=0.362). Mild increases in serum creatinine and INR were noted in the MB group. Conclusion: Early methylene blue administration was associated with improved hemodynamic stability and reduced vasopressor exposure in patients with refractory shock. However, no significant survival or ICU outcome benefit was demonstrated. Larger prospective studies are required to confirm its clinical utility, safety profile, and optimal timing of administration.