The Effect of Methylene Blue on Sublingual Microcirculation in Patients with Septic Shock: A Randomized Controlled...

Methylene blue (MB) has been proposed as an adjunctive therapy in the early management of septic shock; however, its effects on microcirculatory function remain poorly understood. This study aimed to investigate whether MB infusion improves sublingual microcirculatory parameters in patients with septic shock.

In this single-center, randomized controlled trial, participants were allocated in a 1:1 ratio to either the MB group or the control group. The MB group received an intravenous bolus of 2 mg/kg MB over 15 minutes, followed by a continuous infusion of 1 mg/kg MB diluted in 500 mL of 0.9% saline via a central venous catheter for 12 hours. The control group received an equivalent volume of saline. The primary endpoint was the change in sublingual microcirculation parameters from baseline to 24 hours, assessed using a repeated-measures mixed-effects model. Secondary endpoints included 28-day organ support-free days and 28-day mortality.

Among the 72 randomized participants, 70.8% (n=51) were male, with a mean age of 68.6±13.5 years. Following MB treatment, the mean microvascular flow index (MFI) in the MB group was 2.78, compared to 2.51 in the control group. MMRM analysis demonstrated that MB significantly improved MFI (least squares mean difference [95% CI]: 0.21 [0.09, 0.33], P=0.001), with significant increases observed as early as 1 hour post-intervention (T1: 0.24 [0.06, 0.42], P=0.009), and this effect persisted up to 24 hours (T24: P=0.005). However, no significant differences were observed between the groups in 28-day mortality (25.0% [9/36] vs 41.7% [15/36], P=0.200) or organ support-free days (20.0 [1.0-22.0] vs 16.0 [1.3-22.0], P=0.910).

Although MB improved sublingual microcirculatory parameters, these improvements did not translate into benefits in organ function or survival outcomes.

chictr.org.cn ChiCTR 2400081549.