Objective: We aimed to determine whether the restrictive red-cell transfusion strategy was superior to the liberal one in reducing all-cause mortality in critically ill adults. Methods: The MEDLINE, EMBASE, PubMed, Web of Science, and Cochrane Library Central Register of Controlled Trials databases were searched from inception to January 2019 to identify meta-analyses or systematic reviews and published randomized controlled trials which were restrictive versus liberal blood transfusion with mortality as the endpoint in critically ill adults. We used two search routes whereby one search was restricted to systematic reviews, reviews, or meta-analysis, and the other was not restricted. There were no date restrictions, but language was limited to English and the population was restricted to critically ill adults. The data of study methods, participant characteristics, and outcomes were extracted and analyzed independently by 2 reviewers. The main outcome was all-cause mortality. Results: Through screening the obtained records, we enrolled 7 randomized clinical trials that included information on restrictive versus liberal red-cell transfusion and mortality of intensive care unit (ICU) patients. Involving a total of 7,363 ICU adult patients, ICU mortality (risk ratio [RR] 0.82, 95% confidence interval [CI] 0.62, 1.08, p = 0.15), 28/30-day mortality (RR 0.98, 95% CI 0.84, 1.13, p = 0.74), 60-day mortality (RR 1.01, 95% CI 0.87, 1.16, p = 0.91), 90-day mortality (RR 1.02, 95% CI 0.92, 1.14, p = 0.69), 120-day mortality (RR 1.29, 95% CI 0.67, 2.47, p = 0.44), and 180-day mortality (RR 0.91, 95% CI 0.75, 1.12, p = 0.38) were not statistically significantly different when the restrictive transfusion strategy was compared with the liberal transfusion strategy. However, we surprisingly discovered that 112 out of 469 (24%) patients who received a unit RBC transfusion when hemoglobin was less than 7 g/dL, and 142 out of 469 (30.3%) who received a unit of RBC transfused with hemoglobin less than 9 g/dL, had died during hospitalization (RR 0.79, 95% CI 0.64, 0.97, p = 0.03). The results showed that the restrictive transfusion strategy could decrease in-hospital mortality compared with the liberal transfusion strategy. It was safe to utilize a restrictive transfusion threshold of less than 7 g/dL in stable critically ill adults. Conclusions: In this study, we found that the restrictive redcell transfusion strategy potentially reduced in-hospital mortality in critically ill adults with anemia compared with the liberal strategy. © 2020 S. Karger AG, Basel

中文翻译：

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危重患者的自由输血与限制性输血和结果：荟萃分析

目的：我们旨在确定限制性红细胞输血策略在降低重症成人全因死亡率方面是否优于自由输血策略。方法：检索 MEDLINE、EMBASE、PubMed、Web of Science 和 Cochrane Library Central Register of Controlled Trials 数据库，从开始到 2019 年 1 月，确定荟萃分析或系统评价以及已发表的限制性输血与自由输血的随机对照试验。死亡率作为危重成人的终点。我们使用了两种搜索路径，一种搜索仅限于系统评价、评论或荟萃分析，另一种则不受限制。没有日期限制，但语言仅限于英语，人口仅限于重症患者。研究方法的数据，参与者特征和结果由 2 位评审员独立提取和分析。主要结果是全因死亡率。结果：通过筛选获得的记录，我们纳入了 7 项随机临床试验，其中包括限制性与自由性红细胞输血和重症监护病房 (ICU) 患者死亡率的信息。共涉及 7,363 名 ICU 成年患者，ICU 死亡率（风险比 [RR] 0.82，95% 置信区间 [CI] 0.62，1.08，p = 0.15），28/30 天死亡率（RR 0.98，95% CI 0.84， 1.13, p = 0.74), 60 天死亡率 (RR 1.01, 95% CI 0.87, 1.16, p = 0.91), 90 天死亡率 (RR 1.02, 95% CI 0.92, 1.14, p = 0.69), 120 天死亡率（RR 1.29, 95% CI 0.67, 2.47, p = 0.44）和 180 天死亡率（RR 0.91, 95% CI 0.75, 1.12, p = 0. 38) 当限制性输血策略与自由输血策略进行比较时，差异无统计学意义。然而，我们惊奇地发现，在血红蛋白低于 7 g/dL 时接受一个单位 RBC 输血的 469 名患者中有 112 名（24%），而在 469 名患者中，有 142 名（30.3%）接受了低于 7 g/dL 的红细胞输注。大于 9 g/dL，住院期间死亡 (RR 0.79, 95% CI 0.64, 0.97, p = 0.03)。结果表明，与自由输血策略相比，限制性输血策略可以降低住院死亡率。在稳定的危重患者中使用小于 7 g/dL 的限制性输血阈值是安全的。结论：在这项研究中，我们发现，与宽松策略相比，限制性红细胞输血策略可能会降低患有贫血的危重成人患者的住院死亡率。© 2020 S. Karger AG，巴塞尔