Background Microbial dysbiosis in critically ill patients is a leading cause of mortality and septic complications. Probiotics and synbiotics have emerged as novel therapy on gut microbiota to prevent septic complications. However, current evidence on their effects is conflicting. This work aims to systematically review the impact of probiotics or synbiotics in critically ill adult patients. Methods A comprehensive search of the PubMed, CBM, Embase, CENTRAL, ISI, and CNKI databases was performed to identify randomized controlled trials that evaluate probiotics or synbiotics in critically ill patients. The quality assessment was based on the modified Jadad's score scale and the Cochrane Handbook for Systematic Reviews of Interventions Version 5.0.1. The major outcome measure was mortality. Secondary outcomes included incidence of septic complications, sepsis incidence, length of intensive care unit (ICU) stay, incidence of non-septic complication, and ventilator day. Data synthesis was conduct by Review Manager 5.4. Results A total of 25 randomized controlled trials reporting on 5049 critically ill patients were included. In the intervention group, 2520 participants received probiotics or synbiotics, whereas 2529 participants received standard care or placebo. Pooling data from randomized controlled trials demonstrated a significant reduction in the incidence of ventilator-associated pneumonia (VAP) in the treatment group [(risk ratio (RR) 0.86; 95% confidence interval (CI): 0.78-0.95; p < 0.003, I2 = 85%)]. However, in the subgroup analysis, the reduction of incidence of VAP was only significant in patients receiving synbiotics (RR = 0.61, 95% CI: 0.47-0.80, p = 0.0004, I2 = 40%) and not significant in those receiving only probiotics (RR = 0.91, 95% CI: 0.82-1.01, p = 0.07, I2 = 65%). Moreover, sepsis incidence of critically ill patients was only significantly reduced by the addition of synbiotics (RR = 0.41; 95% CI: 0.22-0.72, p = 0.005, I2 = 0%). The incidence of ICU-acquired infections was significantly reduced by the synbiotics therapy (RR = 0.72; 95% CI: 0.58-0.89, p = 0.0007, I2 = 79%). There was no significant difference in mortality, diarrhea, or length of ICU stay between the treatment and control groups. Conclusions Synbiotics is an effective and safe nutrition therapy in reducing septic complications in critically ill patients. However, in such patients, administration of probiotics alone compared with placebo resulted in no difference in the septic complications.

中文翻译：

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益生菌或合生元对危重成人患者的疗效：随机对照试验的系统评价和荟萃分析。

背景 危重患者的微生物菌群失调是导致死亡和脓毒症并发症的主要原因。益生菌和合生元已成为肠道微生物群预防感染并发症的新疗法。然而，目前关于其影响的证据是相互矛盾的。这项工作旨在系统评价益生菌或合生元对危重成年患者的影响。方法 对 PubMed、CBM、Embase、CENTRAL、ISI 和 CNKI 数据库进行全面搜索，以确定评估危重患者益生菌或合生元的随机对照试验。质量评估基于修改后的 Jadad 评分量表和 Cochrane 干预系统评价手册 5.0.1 版。主要结局指标是死亡率。次要结局包括脓毒症并发症的发生率、脓毒症发生率、重症监护病房 (ICU) 住院时间、非脓毒症并发症的发生率和呼吸机天数。数据合成由 Review Manager 5.4 进行。结果共纳入25项随机对照试验，报告5049例重症患者。在干预组中，2520 名参与者接受了益生菌或合生元，而 2529 名参与者接受了标准护理或安慰剂。来自随机对照试验的汇总数据表明，治疗组呼吸机相关性肺炎 (VAP) 的发生率显着降低 [（风险比 (RR) 0.86；95% 置信区间 (CI)：0.78-0.95；p < 0.003， I2 = 85%)]。然而，在亚组分析中，VAP 发病率的降低仅在接受合生元的患者中显着（RR = 0.61, 95% CI: 0.47-0.80, p = 0.0004, I2 = 40%），而在仅接受益生菌的患者中不显着（RR = 0.91, 95% CI：0.82-1.01，p = 0.07，I2 = 65%）。此外，只有添加合生元才能显着降低危重患者的脓毒症发病率（RR = 0.41；95% CI：0.22-0.72，p = 0.005，I2 = 0%）。合生元治疗显着降低了 ICU 获得性感染的发生率（RR = 0.72；95% CI：0.58-0.89，p = 0.0007，I2 = 79%）。治疗组和对照组在死亡率、腹泻或ICU停留时间方面没有显着差异。结论合生元在减少危重患者脓毒症并发症方面是一种有效、安全的营养疗法。然而，在此类患者中，