Parenteral lipid emulsions in critical care are traditionally based on soybean oil (SO) and rich in pro-inflammatory omega-6 fatty acids (FAs). Parenteral nutrition (PN) strategies with the aim of reducing omega-6 FAs may potentially decrease the morbidity and mortality in critically ill patients. A systematic search of MEDLINE, EMBASE, CINAHL and CENTRAL was conducted to identify all randomized controlled trials in critically ill patients published from inception to June 2021, which investigated clinical omega-6 sparing effects. Two independent reviewers extracted bias risk, treatment details, patient characteristics and clinical outcomes. Random effect meta-analysis was performed. 1054 studies were identified in our electronic search, 136 trials were assessed for eligibility and 26 trials with 1733 critically ill patients were included. The median methodologic score was 9 out of 14 points (95% confidence interval [CI] 7, 10). Omega-6 FA sparing PN in comparison with traditional lipid emulsions did not decrease overall mortality (20 studies; risk ratio [RR] 0.91; 95% CI 0.76, 1.10; p = 0.34) but hospital length of stay was substantially reduced (6 studies; weighted mean difference [WMD] − 6.88; 95% CI − 11.27, − 2.49; p = 0.002). Among the different lipid emulsions, fish oil (FO) containing PN reduced the length of intensive care (8 studies; WMD − 3.53; 95% CI − 6.16, − 0.90; p = 0.009) and rate of infectious complications (4 studies; RR 0.65; 95% CI 0.44, 0.95; p = 0.03). When FO was administered as a stand-alone medication outside PN, potential mortality benefits were observed compared to standard care. Overall, these findings highlight distinctive omega-6 sparing effects attributed to PN. Among the different lipid emulsions, FO in combination with PN or as a stand-alone treatment may have the greatest clinical impact. Trial registration PROSPERO international prospective database of systematic reviews (CRD42021259238).

中文翻译：

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肠外脂肪乳剂的 Omega-6 保护作用——对危重患者临床结果的最新系统评价和荟萃分析

重症监护中的肠外脂肪乳剂传统上以大豆油 (SO) 为基础，富含促炎性 omega-6 脂肪酸 (FA)。旨在减少 omega-6 FA 的肠外营养 (PN) 策略可能会降低危重患者的发病率和死亡率。对 MEDLINE、EMBASE、CINAHL 和 CENTRAL 进行了系统检索，以识别从开始到 2021 年 6 月发表的所有危重患者随机对照试验，这些试验调查了临床 omega-6 保留效应。两名独立评审员提取了偏倚风险、治疗细节、患者特征和临床结果。进行了随机效应荟萃分析。我们的电子检索发现了 1054 项研究，评估了 136 项试验的资格，并纳入了涉及 1733 名重症患者的 26 项试验。中位方法学评分为 9 分（满分 14 分）（95% 置信区间 [CI] 7, 10）。与传统脂肪乳剂相比，保留 Omega-6 FA 的 PN 并未降低总体死亡率（20 项研究；风险比 [RR] 0.91；95% CI 0.76, 1.10；p = 0.34），但住院时间大幅缩短（6 项研究） ；加权平均差[WMD] − 6.88；95% CI − 11.27，− 2.49；p = 0.002）。在不同的脂肪乳剂中，含有 PN 的鱼油 (FO) 缩短了重症监护时间（8 项研究；WMD - 3.53；95% CI - 6.16，- 0.90；p = 0.009）和感染并发症发生率（4 项研究；RR 0.65；95% CI 0.44，0.95；p = 0.03）。当 FO 作为 PN 之外的独立药物使用时，与标准护理相比，观察到了潜在的死亡率益处。总体而言，这些发现强调了 PN 带来的独特 omega-6 保护效应。在不同的脂肪乳剂中，FO 与 PN 联合或作为独立治疗可能具有最大的临床影响。试验注册PROSPERO国际前瞻性系统评价数据库（CRD42021259238）。