Methylene Blue Reduces Mortality in Critically Ill and Perioperative Patients: A Meta-Analysis of Randomized Trials

Protective hemodynamics: a novel strategy to manage blood pressure

PURPOSE OF REVIEW

This editorial aims to highlight the evolving concept of protective hemodynamics in the management of critically ill patients.

RECENT FINDINGS

Recent literature underscores the limitations of rigid blood pressure targets, particularly in the context of critical care and perioperative management. High blood pressure targets, especially when coupled with high-dose vasopressors, can lead to poor outcomes. 'Protective hemodynamics' aims to maintain cardiovascular stability while reducing risks associated with interventions.

SUMMARY

The implications of adopting protective hemodynamics are profound for both clinical practice and research. Clinically, this approach can reduce iatrogenic harm and improve long-term outcomes for critically ill patients. For research, it opens new avenues for investigating individualized hemodynamic management strategies that prioritize overall patient stability and long-term health over rigid target attainment.

Anesthesia for Combined Heart-Liver Transplantation: A Narrative Review

In 1984, 21 years after the first liver transplantation, Thomas Starzl achieved a milestone by performing the world's first combined heart-liver transplantation. While still uncommon, the practice of combined heart-liver transplants is on the rise globally. In this review, the authors delve into the current literature on this procedure, highlighting the evolving landscape and key considerations for anesthesiologists. Over the years, there has been a remarkable increase in the number of combined heart-liver transplantations conducted worldwide. This surge is largely attributed to the growing population of adult survivors with single-ventricle physiology, palliated with a Fontan procedure, who later present with late Fontan failure and Fontan-associated liver disease. Research indicates that combined heart-liver transplantation is an effective treatment option, with reported outcomes comparable with isolated heart or liver transplants. Managing anesthesia during a combined heart-liver transplant procedure is challenging, especially in the context of underlying Fontan physiology. International experience in this field remains somewhat limited, with most techniques derived from expert opinions or experiences with single-organ heart and liver transplants. These procedures are highly complex and performed infrequently. As the number of combined heart-liver transplants continues to rise globally, there is a growing need for clear guidance on periprocedural surgical and anesthetic management. Anesthesiologists overseeing these patients must consider multiple factors, balancing various comorbidities with significant hemodynamic and metabolic shifts. An increase in (multicenter) studies focusing on specific interventions to enhance patient and organ outcomes is anticipated in the coming years.

Methylene Blue in Septic Shock: A Systematic Review and Meta-Analysis

OBJECTIVES

Although clinicians may use methylene blue (MB) in refractory septic shock, the effect of MB on patient-important outcomes remains uncertain. We conducted a systematic review and meta-analysis to investigate the benefits and harms of MB administration in patients with septic shock.

DATA SOURCES

We searched six databases (including PubMed, Embase, and Medline) from inception to January 10, 2024.

STUDY SELECTION

We included randomized clinical trials (RCTs) of critically ill adults comparing MB with placebo or usual care without MB administration.

DATA EXTRACTION

Two reviewers performed screening, full-text review, and data extraction. We pooled data using a random-effects model, assessed the risk of bias using the modified Cochrane tool, and used Grading of Recommendations Assessment, Development, and Evaluation to rate certainty of effect estimates.

DATA SYNTHESIS

We included six RCTs (302 patients). Compared with placebo or no MB administration, MB may reduce short-term mortality (RR [risk ratio] 0.66 [95% CI, 0.47-0.94], low certainty) and hospital length of stay (mean difference [MD] -2.1 d [95% CI, -1.4 to -2.8], low certainty). MB may also reduce duration of vasopressors (MD -31.1 hr [95% CI, -16.5 to -45.6], low certainty), and increase mean arterial pressure at 6 hours (MD 10.2 mm Hg [95% CI, 6.1-14.2], low certainty) compared with no MB administration. The effect of MB on serum methemoglobin concentration was uncertain (MD 0.9% [95% CI, -0.2% to 2.0%], very low certainty). We did not find any differences in adverse events.

CONCLUSIONS

Among critically ill adults with septic shock, based on low-certainty evidence, MB may reduce short-term mortality, duration of vasopressors, and hospital length of stay, with no evidence of increased adverse events. Rigorous randomized trials evaluating the efficacy of MB in septic shock are needed.

REGISTRATION

Center for Open Science (https://osf.io/hpy4j).

Administration of methylene blue in septic shock: pros and cons

Septic shock typically requires the administration of vasopressors. Adrenergic agents remain the first choice, namely norepinephrine. However, their use to counteract life-threatening hypotension comes with potential adverse effects, so that non-adrenergic vasopressors may also be considered. The use of agents that act through different mechanisms may also provide an advantage. Nitric oxide (NO) is the main driver of the vasodilation that leads to hypotension in septic shock, so several agents have been tested to counteract its effects. The use of non-selective NO synthase inhibitors has been of questionable benefit. Methylene blue, an inhibitor of soluble guanylate cyclase, an important enzyme involved in the NO signaling pathway in the vascular smooth muscle cell, has also been proposed. However, more than 25 years since the first clinical evaluation of MB administration in septic shock, the safety and benefits of its use are still not fully established, and it should not be used routinely in clinical practice until further evidence of its efficacy is available.

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

OBJECTIVE

This meta-analysis aimed to demonstrate the effect of methylene blue (MB) in patients with distributive shock.

DESIGN

Meta-analysis.

METHODS

According 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).

RESULTS

This 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).

CONCLUSIONS

The 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 NUMBER

CRD42023415938.