目的:通过系统评价方法观察低分子肝素对急性呼吸窘迫综合征（ARDS）患者临床疗效的影响。方法:检索PubMed数据库、Cochrane图书馆数据库、科学网（Web of Science）、中国知网（CNKI）、中国生物医学文献数据库（CBM）、维普数据库、万方数据库从建库至2020年9月发表的关于比较低分子肝素与常规治疗对急性肺损伤/急性呼吸窘迫综合征（ALI/ARDS）患者疗效及预后影响的随机对照试验（RCT）。常规治疗组给予常规治疗，低分子肝素组在常规治疗基础上加用低分子肝素。结局指标为氧合指数（PaOn 2/FiOn 2）、急性生理学与慢性健康状况评分Ⅱ（APACHEⅡ）、活化部分凝血活酶时间（APTT）、凝血酶原时间（PT）、血小板计数（PLT）、白细胞介素-6（IL-6）及7 d和28 d病死率。按照拟定的纳入和排除标准筛选文献；使用Cochrane协作网评估工具评价文献质量；Meta分析运用RevMan 5.3软件，对纳入≥11篇文献的结局指标进行漏斗图分析，评价纳入文献的发表偏倚。n 结果:最终纳入12项RCT，共623例患者。Meta分析结果表明：与常规治疗组比较，低分子肝素组PaOn 2/FiOn 2明显升高〔均数差（n MD）＝72.08，95%可信区间（95%n CI）为56.92～87.24，n P<0.000 01〕，APACHEⅡ评分（n MD＝-4.34，95%n CI为-5.73～-2.96，n P<0.000 01）、IL-6〔标准化均数差（n SMD）＝-2.13，95%n CI为-2.71～-1.56，n P<0.000 01〕和7 d病死率〔相对危险度（n RR）＝0.52，95%n CI为0.30～0.90，n P＝0.02〕及28 d病死率（n RR＝0.55，95%n CI为0.34～0.90，n P＝0.02）均明显降低，APTT明显缩短（n MD＝-0.88，95%n CI为-1.51～-0.26，n P＝0.006）；但两组PT（n MD＝-0.44，95%n CI为-1.23～0.36，n P＝0.28）和PLT（n MD＝-0.08，95%n CI为-18.81～18.65，n P＝0.99）差异均无统计学意义。对纳入文献为11篇的PaOn 2/FiOn 2进行漏斗图分析，结果显示本研究文献可能存在一定发表偏倚。n 结论:低分子肝素可改善ARDS患者氧合不良情况，降低ARDS患者急性期内病死率，并能减轻炎症反应，但可能有一定的出血风险。“,”Objective:To observe the clinical effect of low molecular weight heparin on the curative effect of acute respiratory distress syndrome (ARDS) patients through a systematic evaluation method.Methods:Databases such as PubMed, Cochrane Library database, Web of Science, CNKI, China Biological Medical Literature Database (CBM), VIP, Wanfang database were searched to retrieve randomized controlled trials (RCTs) on low molecular weight heparin and conventional treatment on the efficacy and prognosis of patients with acute lung injury (ALI)/ARDS from the establishment of the database to September 2020. The conventional treatment group was given conventional treatment, and the low molecular heparin group was given low molecular heparin based on conventional treatment. Outcome indicators were oxygenation index (PaOn 2/FiOn 2), acute physiology and chronic health evaluation Ⅱ(APACHEⅡ), activated partial thromboplastin time (APTT), prothrombin time (PT), platelet count (PLT), interleukin-6 (IL-6) and the mortality at 7 days and 28 days. The literature was screened according to the proposed inclusion and exclusion criteria; the Cochrane collaboration evaluation tool was used to evaluate the quality of literature; Meta analysis used RevMan 5.3 software to perform funnel plot analysis on the outcome indicators of the included ≥11 literatures, and to evaluate the publication bias.n Results:A total of 12 RCTs and 623 patients were included. The results of Meta analysis showed that PaOn 2/FiOn 2 increased in the low molecular weight heparin group compared with the conventional treatment group [mean difference (n MD) = 72.08, 95% confidence interval (95%n CI) was 56.92-87.24, n P < 0.000 01], APACHEⅡ( n MD = -4.34, 95%n CI was -5.73 to -2.96, n P < 0.000 01), IL-6 [standardized mean difference ( n SMD) = -2.13, 95%n CI was -2.71 to -1.56, n P < 0.000 01] and 7-day mortality [relative risk ( n RR) = 0.52, 95%n CI was 0.30-0.90, n P = 0.02] and 28-day mortality (n RR = 0.55, 95%n CI was 0.34-0.90, n P = 0.02) were significantly reduced, APTT was significantly shortened (n MD = -0.88, 95%n CI was -1.51 to -0.26, n P = 0.006); but PT (n MD = -0.44, 95%n CI was -1.23 to 0.36, n P = 0.28) and PLT (n MD = -0.08, 95%n CI was -18.81 to 18.65, n P = 0.99) between the two groups had no statistically significant differences. A funnel chart analysis of PaOn 2/FiOn 2 with 11 included papers showed that there might be publication bias.n Conclusion:Low molecular weight heparin can improve the poor oxygenation of ARDS patients, reduce the mortality of ARDS patients in the acute stage and the inflammatory reaction, but it may increase the bleeding risk of ARDS patients.