Effect of methylene blue on outcomes in patients with distributive shock: a meta-analysis of randomised controlled trials

ObjectiveThis meta-analysis aimed to demonstrate the effect of methylene blue (MB) in patients with distributive shock.DesignMeta-analysis.MethodsAccording to the Prospective International Register of Systematic Reviews (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, we searched the relevant randomised controlled trials (RCTs) via PubMed, Embase and Cochrane Library from the date of database inception to 19 April 2023. The primary outcome was mortality during follow-up, and secondary outcomes included mean arterial pressure (mm Hg), mechanical ventilation time (hours), intensive care unit (ICU) length of stay (LOS) (days), hospital LOS (days) and heart rate (times/min).ResultsThis study included six RCTs with 265 participants. The study showed no significant difference in mortality between the MB and placebo groups (ORs: 0.59; 95% CI 0.32 to −1.06). However, MB reduced the duration of mechanical ventilation (mean difference (MD): −0.68; 95% CI −1.23 to −0.14), ICU LOS (MD: −1.54; 95% CI −2.61 to −0.48) and hospital LOS (MD: −1.97; 95% CI −3.92 to −0.11).ConclusionsThe use of MB may not reduce mortality in patients with distributive shock, but may shorten the duration of mechanical ventilation, ICU LOS and hospital LOS. More clinical studies are needed to confirm these findings in the future.Trial registration numberCRD42023415938.