N‐acetylcysteine for adults with acute respiratory distress syndrome: A meta‐analysis of randomized controlled trials

Background: Acute respiratory distress syndrome is regarded as a formidable clinical challenge due to its high prevalence and mortality. The treatment of acute respiratory distress syndrome is very complex and difficult. As an adjuvant therapy, the antioxidant N‐acetylcysteine has been investigated for several years but the benefit is controversial. Objectives: We performed the systematic review and meta‐analysis of randomized controlled trials to evaluate the efficacy of N‐acetylcysteine on patients with acute respiratory distress syndrome. Methods: We searched PubMed, CENTRAL, and CBM databases. Randomized controlled trials comparing the effects of N‐acetylcysteine and control were included. Overall mortality was the primary outcome; length of intensive care unit stay, duration of mechanical ventilation, glutathione levels, and PaO 2 /FiO 2 were the secondary outcomes. Results: Eight trials with a total of 289 patients were included. Compared to the control group, the N‐acetylcysteine group did not lower the overall mortality (risk ratio: 0.83; 95% confidence interval: 0.62 to 1.11; P = 0.21; I 2  = 0%). However, N‐acetylcysteine significantly shortened intensive care unit stay in the random‐effects model (mean difference: –4.47 days; 95% confidence interval: –8.79 to −0.14; P = 0.04; I 2  = 46%). Due to substantial heterogeneity and limited number of studies, the data of duration of mechanical ventilation, glutathione levels, and PaO 2 /FiO 2 could not be pooled in the meta‐analysis. Conclusion: N‐acetylcysteine is ineffective in reducing mortality but beneficial for intensive care unit stay. Nonetheless, the effectiveness of N‐acetylcysteine for acute respiratory distress syndrome is limited and further research is required before strong recommendations can be made.