Objective: Vasoplegic shock, sometimes referred to as distributive shock, is a life-threatening clinical syndrome involving systemic vasodilation and is associated with significant morbidity and mortality in intensive care unit (ICU) patients. The most common etiology is sepsis; others include post-cardiac bypass vasoplegia and various toxidromes. Key components of management include fluid resuscitation and vasopressors to restore vascular tone. Methylene blue selectively targets inducible nitric oxide synthase, a key component of early vasodilation in response to inflammation. We investigated whether the timing of administration of methylene blue influences clinical response, as measured by subsequent vasopressor requirements, fluid resuscitation, organ system function, and mortality.
Design: This study was a retrospective case series including 33 cases. Data were collected for each case, including timing of administration, vasopressor and fluid requirements, Sequential Organ Failure Assessment (SOFA) scores, and in-hospital mortality. A Spearman’s rank correlation was performed to assess the correlation between the timing of administration of methylene blue and improvement in relevant clinical parameters.
Setting: A large metropolitan Intensive Care Unit (47 beds).
Patients and participants: Included in this study were adult patients who received methylene blue in the participating ICU between 2020 and 2022 for managing vasoplegic shock.
Interventions: Administration of intravenous methylene blue.
Measurements and results: No correlation between the timing of administration and reduction in vasopressor requirements was observed. Administration of methylene blue within 8 hours of the onset of shock refractory to 5 mcg/min of noradrenaline was found to weakly correlate with reduced total SOFA score on Day 1 (Rs=0.39, p=0.04), and patients who received methylene blue within eight hours had a lower mortality (60.0% vs 78.2%).
Conclusions: These findings suggest that a prolonged period of vasoplegic shock before consideration of methylene blue should not discourage its use. A prospective randomized control study will be a valuable direction for future research.