摘要目的：评价低分子肝素皮下注射时推注时间对注射部位皮下出血发生率及面积大小的影响。方法检索Cochrane图书馆、JBI循证实践医疗与护理数据库、PubMed生物医学信息检索平台、Medline全科性医药学文献检索数据库等中英文数据库，纳入关于低分子肝素皮下注射推注时间对注射部位皮下出血的影响的随机对照试验和类试验研究，采用RevMan 5.3软件分析数据。结果共纳入9篇文献，Meta分析结果显示，低分子肝素皮下注射时推注30 s较推注10 s降低了注射部位皮下出血的发生率（优势比为0.34，95%可信区间为0.25～0.47，P＜0.01）；延长推注时间至30 s对注射部位48、72 h皮下出血面积及48 h皮下出血直径均无明显作用（P＞0.05）。结论低分子肝素皮下注射时延长推注时间可降低皮下出血的发生率，但对皮下出血面积或直径的大小并无明显影响。

abstractsObjective To evaluate the effect of duration of subcutaneous injection on the extent of bruising at injection sites among patients receiving low- molecular weight heparin. Methods Randomized clinical trials and quasi-experimental within-subject design that assessed the effect of subcutaneous duration on the bruising of injection sites were selected in Cochrane library, JBI evidence-based practice medical and nursing database, PubMed biomedical information retrieval platform, Medline general medical literature retrieval database. RevMan5.3 software was used to analyze the data after quality assessment, and data extraction were made for eligible trials. Results A total of 9 trials were included. The results of Meta-analysis supported the 30 s duration injection technique on reducing the rate of bruising of injection sites than 10 s duration injection technique (odds ratio was 0.34,95%confidence interval 0.25-0.47, P<0.01).While it was failed to support the effect on reducing the bruising area 48 and 72 hours after injection (P > 0.05). Conclusions Increasing the length of low-molecular weight heparin subcutaneous injection can reduce the rate of bruising. While it could not effectively reduce the area.