Low-molecular-weight heparin treatment for acute lung injury/acute respiratory distress syndrome: a meta-analysis of randomized controlled trials

Low-molecular-weight heparin (LMWH) has achieved additional benefits among acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) patients. We aimed to evaluate the benefits of LMWH as an adjunctive therapy in ALI/ARDS patients by conducting meta-analysis. We made a comprehensive literature search using Pubmed, Embase, Cochrane Library, Wanfang, VIP, and CKNI until October 2016. Randomized controlled trials evaluating LMWH as an adjunctive therapy for ALI/ARDS patients were included. A total of 9 trials involving 465 patients were identified. Adjunctive treatment with LMWH significantly reduced the 28-day mortality (risk ratio [RR] 0.63; 95% confidence interval [CI] 0.41-0.96), 7-day mortality rate (RR 0.52; 95% CI 0.31-0.87), and activated partial thrombin time (weighted mean differences [WMD] -1.10 seconds; 95% CI -1.97 to -0.23) as well as increased the partial pressure of oxygen to fraction of inspired oxygen ratio (PaO2/FiO(2)) (WMD 74.48; 95% CI 52.18-96.78). However, the tested LMWH dose had no apparent effect on prothrombin time and platelet count. Subgroup analyses showed that the effect on PaO2/FiO(2) improvement was more pronounced in the high LMWH dose (>= 5000 U/day) subgroup. This meta-analysis suggests that adjunctive treatment with LMWH appears to have additional benefits in terms of reducing 7-day and 28-day mortality and increasing oxygen index among ALI/ARDS patients.