Abstract:Objective To systematically evaluate the efficacy of ulinastatin in the treatment of severe pneumonia.Methods A systematic review of ulinastatin in the treatment of severe pneumonia was performed systematically using a systematic review provided by the Cochrane Collaboration. The randomized controlled trials of ulinastatin treatment in patients with severe pneumonia were searched from the Cochrane Library, Pubmed, Embase, Clinicalkey, China National Knowledge Infrastructure database, Chinese Biological Medicine, VIP, and Wanfang database by computer. Data were collected from inception to June 2019. Meta-analysis was performed using RevMan 5.3.0 software provided by the Cochrane Collaboration, after two researchers independently screened the literature, extracted data, and assessed the risk of bias in the included literature.Results A total of 15 studies involving 1373 participants were enrolled for Meta-analysis according to the inclusion and exclusion criteria. The results showed that compared with the group of routine therapies, the experimental group of ulinastatin was superior in the following aspects with significant differences: WBC [MD = -2.37 (95% CI: -2.95, -1.79)], CRP [SMD = -2.01 (95% CI: -2.86, -1.16)], IL-8 [SMD = -2.13 (95% CI: -2.37, -1.89)], TNF-α [SMD = -1.37 (95% CI: -1.87, -0.86)], oxygenation Index [SMD = 1.78 (95% CI: 1.05, 2.50)], the average length of hospital stay [MD = -7.21, (95% CI: -9.21, -5.21)], overall efficiency [R = 1.20, (95% CI: 1.12, 1.28) ] and [R = 1.24 (95% CI: 1.13, 1.37) ].Conclusions Ulinastatin can reduce the inflammatory response, improve the oxygenation level, reduce the average hospital stay, and improve the therapeutic effect of patients with severe pneumonia. However, due to the limited quality of the included literature, the above conclusions need to be verified by more high-quality, multi-center, large-scale studies in the future.