摘要目的:评价外源性褪黑素预防重症患者发生谵妄的有效性。方法:计算机检索Pubmed、Medline、Embase、Web of Science、The Cochrane Library等英文数据库关于外源性褪黑素预防重症患者谵妄疗效的随机对照试验，检索时间为建库至2021年3月。由2名研究者按照纳入与排除标准独立筛选文献、提取资料和评价质量。采用Revman 5.3软件进行meta分析。结果:共纳入10项随机对照试验和1 224例重症患者。Meta分析结果显示，试验组与对照组重症患者住院期间谵妄发生率[相对危险度(relative risk, RR)0.72，95%置信区间(confidence interval, CI)0.47~1.09； Z＝1.57， P＝0.12]、ICU住院时间[均数差(mean difference, MD)-0.36，95% CI -1.01~0.28； Z＝1.11， P＝0.27]、机械通气时间( MD -49.42，95% CI -126.63~27.80； Z＝1.25， P＝0.21)和病死率( RR 0.74，95% CI 0.42~1.30； Z＝1.05， P＝0.29)差异均无统计学意义。 结论:外源性褪黑素不能预防重症患者谵妄的发生，也无法缩短重症监护病房住院时间、机械通气时间及降低病死率。

abstractsObjective:To evaluate the effectiveness of exogenous melatonin in preventing delirium in critically ill patients.Methods:The computer searched Pubmed, Medline, Embase, Web of Science, the Cochrane Library and other English databases for randomized controlled trials on the efficacy of exogenous melatonin in the prevention of delirium in critically ill patients. The retrieval time was from the establishment of the database to March 2021. Two researchers independently screened the literature, extracted data and evaluated the quality according to the inclusion and exclusion criteria. Revman 5.3 software was used for meta-analysis.Results:A total of 10 randomized controlled trials and 1 224 critically ill patients were included. The results of meta-analysis showed that there were no significant differences in the incidence of delirium during hospitalization (relative risk [ RR] 0.72, 95% confidence interval [ CI] 0.47-1.09; Z=1.57, P=0.12), ICU hospitalization time (mean difference [ MD] -0.36, 95% CI -1.01-0.28; Z=1.11, P=0.27), mechanical ventilation time ( MD -49.42, 95% CI -126.63-27.80; Z=1.25, P=0.21) and mortality ( RR 0.74, 95% CI 0.42-1.30; Z=1.05, P=0.29) between the experimental group and the control group. Conclusion:Exogenous melatonin can not prevent the occurrence of delirium in critically ill patients, nor can it shorten the hospitalization time and mechanical ventilation time in intensive care unit and reduce the mortality.