体外膜肺氧合对成人急性呼吸窘迫综合征患者预后影响的Meta分析和系统评价

目的 探讨体外膜肺氧合(ECMO)对急性呼吸窘迫综合征(ARDS)患者预后的影响.方法 计算机检索和手工检索收集1966-2010年ECMO治疗成人ARDS的英文和中文临床研究,按纳入与排除标准选择文献,提取资料,采用RevMan 5.0软件对数据进行Meta分析,对ECMO临床研究进行系统评价.结果 共纳入3篇随机对照研究,随机效应模型显示ECMO不降低成人重症ARDS患者病死率[RR=0.95(95%CI:0.76-1.18),P=0.64],但按发表时间的累积Meta分析显示ECMO呈现保护性效应;与以往临床研究相比,最近一项观察性临床研究显示ECMO明显降低甲型H1N1流感导致的重症ARDS患者病死率.结论 现有研究尚不能证实ECMO能改善成人ARDS患者预后,但对于病因可逆的重症ARDS患者早期应用ECMO可取得较好临床效益.

Abstract：

Objective To investigate the effects of extracorporeal membrane oxygenation (ECMO) on survival of adult from acute respiratory distress syndrome (ARDS). Method We searched Pubmed, Embase, Cochrane Library, Web of Science databases to find relevant literatues on ECMO in treatment of ARDS, which are reported from January 1966 to June 2010. Meta analyses was performed. Results Three papers about randomized controlled trial (RCT) of evaluating ECMO in patients with severe ARDS were enrolled for analyses. Meta-analysis of the three randomized controlled trials revealed ECMO did not decrease the mortality of ARDS patients. However, the cumulative meta-analysis of randomized trials showed ECMO had a protective effect on patients with ARDS. The most recent observational studies suggested that ECMO significantly decreased the mortality of ARDS caused by H1 N1 viral pneumonia. Conclusions There is no evidence to prove the benefit of ECMO in patients with ARDS. However, ECMO should be considered to use in early stage of ARDS as a last rescue resort for potentially reversible severe acute respiratory failure. Further investigation of large sample of high quality RCTs is needed.     

体外膜肺氧合对成人急性呼吸窘迫综合征患者预后影响的荟萃分析

目的 评估体外膜肺氧合(ECMO)对成人急性呼吸窘迫综合征(ARDS)患者预后的影响.方法 计算机检索和手工检索收集1966年1月至2011年7月ECMO治疗成人ARDS的英文和中文临床研究文献,按纳入与排除标准选择文献,提取资料,采用RevMan 5.0软件对数据进行荟萃分析(Meta分析).结果 共纳入9篇文献,其中3篇为随机对照临床试验(RCT)研究,6篇为观察性研究.3篇RCT研究共入选310例患者,ECMO治疗组159例,对照组151例;Meta分析显示:与传统机械通气治疗相比,ECMO治疗不能降低成人重症ARDS患者病死率[优势比(OR)=0.75,95％可信区间(95％CI) 0.45～1.24,P=0.27].9篇文献共入选1058例患者,ECMO治疗组386例,对照组672例;Meta分析显示,与传统机械通气治疗相比,ECMO治疗增加了成人重症ARDS患者的病死率(OR=1.58,95％CI 0.94 ～ 2.67,P=0.08).结论 通过对现有研究的Meta分析表明,ECMO不能改善成人ARDS患者的预后.但由于研究数量较少,研究人群异质性等因素影响,仍需要进行更多大样本、高质量的RCT研究.     

影响体外膜肺治疗重症急性呼吸窘迫综合征预后的因素分析

目的 分析接受体外膜肺(ECMO)治疗重症急性呼吸窘迫综合征(ARDS)患者的临床特征,探讨影响ECMO治疗重症ARDS预后的因素.方法 回顾性分析法国斯特拉斯堡医学院附属新民众医院2008年11月至2010年9月因常规治疗无效而行ECMO辅助的重症急性呼吸窘迫综合征患者的临床资料,将接受动脉-静脉ECMO治疗患者和ECMO治疗前接受机械辅助通气超过10 d的患者排除在外,根据ECMO治疗后28 d的存活情况,分为存活组和死亡组,比较分析两组患者在转入ICU以及接受ECMO治疗前后的临床特征,通过组间单因素分析筛选出影响ECMO治疗重症ARDS效果的主要因素.结果 共有25例患者进入本研究,其中存活组15例,死亡组10例.研究结果表明,存活组患者年龄明显低于死亡组(49.8±10.5)岁vs.(59.9±11.5)岁,P =0.044,并且存活组患者感染甲型H1N1比例明显高于死亡组(x2=3.896,P=0.048).另外,接受ECMO治疗前,存活组患者机械通气时间明显短于死亡组(57.8±8.7) hvs.(68.3±13.7)h,P=0.013.结论 年龄和接受ECMO治疗前机械通气时间的长短,以及导致重症ARDS的病因是影响ECMO治疗重症ARDS效果的重要因素.     

护理干预对慢性阻塞性肺疾病患者睡眠质量的影响

目的 评价护理干预对慢性阻塞性肺疾病(COPD)患者睡眠质量的影响.方法 通过检索Co-chrane Library、Embase、PubMed、中国学术期刊全文数据库、万方资源数据库,收集护理干预对COPD患者睡眠质量影响的临床研究,按照纳入及排除标准纳入研究并评价质量,提取相关数据,应用Stata 12.0软件进行Meta分析.结果 最终纳入9篇文献,包括724例患者.Meta分析结果显示,各研究间存在异质性(P=0.000,I2=89.9%);通过随机效应模型进行Meta分析显示,经护理干预后,COPD患者PSQI明显降低[SMD=-1.110,95%(-1.477,-0.473),P＜0.001].发表偏倚检测示:本研究不存在发表偏倚.结论 现有临床研究证据显示,护理干预能明显改善COPD患者睡眠质量.但因研究质量及研究样本存在明显异质性,尚需多中心、高质量的临床随机对照实验加以验证.     

糖皮质激素对成人急性呼吸窘迫综合征疗效的Meta分析

目的 评价糖皮质激素对成人急性呼吸窘迫综合征(acute respiratory distress syndrome,ARDS)的疗效.方法 利用计算机检索已公开发表的有关糖皮质激素治疗ARDS的中英文文献,按纳入、排除标准纳入合格文献并进行质量评价,采用Rev Man 5.0软件进行Meta分析.结果 共纳入8项独立研究,含ARDS患者679例(激素组366例,对照组313例),Meta分析结果显示激素组与对照组相比,总病死率、早期治疗患者病死率、小剂量治疗患者病死率、氧合指数(PaO_2/FiO_2)的差异有统计学意义(P<0.05),合并相对危险度(RR)或标准化均数差(SMD)及95%置信区间(CI)依次为0.55(0.34～0.87),0.49(0.28～0.86),0.46(0.24～0.88),2.99(0.63～5.34).而晚期治疗患者病死率、大剂量治疗患者病死率、新发感染率的差异均无统计学意义(P>0.05).结论 早期激素治疗或小剂量激素治疗能够降低ARDS患者的病死率;激素应用后氧合情况有显著改善;激素治疗没有显著增加或减少感染性并发症的发病率.     

肾脏替代治疗开始时机对急性肾损伤患者预后影响的Meta分析

目的系统评价肾脏替代治疗(RRT)开始时机对急性肾损伤(AKI)患者预后的影响。方法通过检索Pub Med、Web of Science、EMBase以及万方数据等数据库2000年1月至2016年5月发表的关于不同时机开始RRT治疗对AKI患者预后影响的随机对照试验(RCT),按Cochrane系统评价手册5.1.0进行质量评价后,采用Rev man 5.3系统软件进行Meta分析,评价早期和晚期开始RRT对AKI患者总病死率、28 d病死率、总住院时间和ICU住院时间的影响,并绘制漏斗图检测发表偏倚。结果共纳入7项RCT,合计1 752例患者。Meta分析结果显示,通过随机效应模型分析得出,早期RRT组和晚期RRT组总体病死率差异无统计学意义[65.7%(226/344)vs.68.7%(239/348),OR=0.81,95%CI=0.58~1.13,P=0.22],漏斗图显示各研究间存在发表偏倚。固定效应模型分析得出,早期RRT组和晚期RRT组28 d病死率差异有统计学意义[39.8%(229/575)vs.46.2%(276/597),OR=0.77,95%CI=0.61~0.97,P=0.03],漏斗图显示各研究间存在发表偏倚。各研究总住院时间和ICU住院时间数据分布不一致,未进行Meta分析,但各研究均显示早期RRT组和晚期RRT组总住院时间差异无统计学意义。结论早期RRT不能显著改善AKI患者的总病死率,但可以降低28 d病死率。     

体外膜肺氧合支持应用于感染甲型H1N1流感病毒危重症患者肺保护策略的Meta分析

目的 探讨体外膜肺氧合(ECMO)支持应用于感染甲型H1N1流感病毒危重症患者肺保护策略的Meta分析。方法 在中国知网(CNKI)、中国生物医学文献数据库(CBM)、维普数据库(VIP)等文献检索网站中输入ECMO、甲型H1N1流感病毒危重症及肺保护等主要关键词,借助于排除法(计算机排除和手工排除)剔除不符合筛选条件的文献,通过全文阅读的方式共选出10篇符合随机对照试验(RCT)的文献进行Meta分析,将其纳入Revman 5. 3统计软件统计分析,采用合并比值比(OR)评价ECMO在感染甲型H1N1流感病毒危重症治疗中的临床疗效和对肺保护的影响并分析其文献偏倚。结果 ①存活组ECMO治疗时间的平均值较死亡组更短,差异有统计学意义(P 0. 05)。②异质性检验和固定效应模型分析发现,10项研究均有异质性(P=0. 01,I2=46. 0%),ECMO支持可保护肺功能(MD=0. 83,P0. 0001)。③ECMO对感染甲型H1N1流感病毒危重症患者的肺功能相对危险度(OR=0. 96)较高,不能改善其病死率,但随研究时间逐渐后移,ECMO对该病患者肺功能预后改善有帮助。④ECMO支持过程中存活组患者的肺功能改善程度较死亡组更优(P 0. 05),但不同干预时间比较差异无统计学意义(P 0. 05)。⑤10项研究中感染甲型H1N1流感病毒危重症患者实施ECMO支持治疗后散点多集中于漏斗图右侧,文献存在偏倚。结论 ECMO支持在一定程度上可改善感染甲型H1N1流感病毒危重症患者预后,病因可逆的感染甲型H1N1流感病毒危重症患者应结合其病情及早予以ECMO治疗,提升临床治疗效益。     

重症急性胰腺炎预防性抗菌药物治疗的Meta分析

目的系统评价重症急性胰腺炎(SAP)预防性应用抗菌药物的疗效及其临床意义,为临床合理使用提供依据。方法计算机检索MEDLINE、EMbase、Cochrane图书馆临床对照试验资料库、CBMdisc和CNKI,检索时间均从建库至2010年8月,收集重症急性胰腺炎预防性使用抗菌药物的随机对照试验(RCT)。对符合纳入标准的临床研究进行资料提取和质量评价后,采用RevMan 5.0软件进行Meta分析。结果最终纳入12个随机对照试验,共777例患者。Meta分析结果显示,与对照组相比,预防性使用抗菌药物组在降低SAP病死率[RR=0.75,95%CI(0.50,1.12)]、减少坏死性胰腺感染[RR=0.82,95%CI(0.63,1.09)]、手术干预[RR=0.97,95%CI(0.74,1.26)]和胰腺外感染[RR=0.73,95%CI(0.48,1.10)]方面均无优势。结论现有临床研究证据显示,SAP患者预防性使用抗菌药物并不能有效降低感染性坏死的发生率、病死率及手术干预率。     

俯卧位通气治疗ARDS患者有效性与安全性的Meta分析

目的 :评价俯卧位通气治疗急性呼吸窘迫综合征患者的有效性及安全性。方法 :计算机检索Pub Med、Embase、Web of Sience、the Cochrane Library、中国知网、中国生物医学文献、维普、万方数据库中发表的关于俯卧位通气对ARDS患者影响的相关研究,纳入文献的质量由两名经过专业循证医学培训的学生完成,采用Rev Man 5.3软件对纳入文献进行Meta分析。结果 :共纳入9篇随机对照试验文献,纳入患者数2 359人。Meta分析结果显示,病死率效应值[OR=0.60,95%CI(0.40,0.90),P=0.01],合并效应有统计学意义;而在意外脱管发生率、呼吸机相关性肺炎发生率、气胸发生率、ICU住院时间方面并无统计学意义。结论 :俯卧位通气可降低ARDS患者病死率,且不增加意外脱管率,但在预防呼吸机相关性肺炎(VAP)、气胸发生率及ICU住院时间方面并无统计学意义。     

气道压力释放通气对急性呼吸窘迫综合征患者住院病死率影响的累积Meta分析

目的 应用累积Meta分析的方法评价气道压力释放通气（APRV）对急性呼吸窘迫综合征（ARDS患者住院病死率的影响。方法 计算机检索PubMed、Web of Science、Cochrane Library、WanFang Data、CNKI和VIP数据库,搜集与研究目的相关的随机对照试验（RCT）,检索时限均为建库至2022年6月30日。由2名研究者独立筛选文献、提取资料并评价纳入研究的偏倚风险后,采用StataSE 12.0软件进行累积Meta分析。结果 共纳入9个RCT,包括533例患者。Meta分析结果显示,与传统机械通气相比,APRV能够降低ARDS患者的住院病死率[RR=0.70,95%CI(0.54,0.91),P<0.01]。结论 当前证据表明,APRV可降低ARDS患者住院病死率。受纳入研究数量和质量的限制,上述结论尚待更多高质量研究予以验证。     

Extracorporeal membrane oxygenation for severe acute respiratory failure

Extracorporeal membrane oxygenation (ECMO) is a technique for providing life support, in case the natural lungs are failing and are not able to maintain a sufficient oxygenation of the body's organ systems. ECMO technique was an adaptation of conventional cardiopulmonary bypass technique and introduced into treatment of severe acute respiratory distress syndrome (ARDS) in the 1970s. The intial reports of the use of ECMO in ARDS patients were quite enthusiastic, however, in the following years it became clear that ECMO was only of benefit in newborns with acute respiratory failure. In neonates treated with ECMO, survival rates of 80% could be achieved. In adult patients with ARDS, two large randomized controlled trials (RCTs) published in 1979 and 1994 failed to show an advantage of ECMO over convential treatment, survival rates were only 10% and 33%, respectively, in the ECMO groups. Since then, ECMO technology as well as conventional treatment of adult ARDS have undergone further improvements. In conventional treatment lung-protective ventilation strategies were introduced and ECMO was made safer by applying heparin-coated equipment, membranes and tubings. Many ECMO centres now use these advanced ECMO technology and report survival rates in excess of 50% in uncontrolled data collections. The question, however, of whether the improved ECMO can really challenge the advanced conventional treatment of adult ARDS is unanswered and will need evaluation by a future RCT.     

Résultats de l’assistance respiratoire extracorporelle dans les syndromes de détresse respiratoire aiguë sévères

Major technological improvements in extracorporeal membrane oxygenation (ECMO) machines and the positive results of the CESAR trial have reignited the interest for veno-venous (VV)-ECMO in patients with severe acute respiratory distress syndrome (ARDS) and persistent hypoxemia or hypercarbia on conventional mechanical ventilation. The technique has also been successfully used for the most severe ARDS cases associated with the recent Influenza A(H1N1) pandemic. However, since the CESAR study was criticized for methodological limitations and because results of non-randomized case-series of ECMO are prone to selection biases, indications for VV-ECMO use remain highly controversial. Before widespread diffusion of VV-ECMO for severe ARDS, new trials should test the efficacy of early initiation of the technique with tight control of mechanical ventilation in the control group, initiation of ECMO prior to transportation to ECMO centers, and the use of ECMO in every patient randomly assigned to receive it.     

Effectiveness of extracorporeal membrane oxygenation when conventional ventilation fails: Valuable option or vague remedy?

The mortality and morbidity of patients with severe acute respiratory distress syndrome (ARDS) remains high despite the advances in intensive care practice. The low-tidal-volume ventilation strategy (ARDS net protocol) has been shown to be effective in improving survival. Unfortunately, however, some patients have such severe ARDS that they cannot be managed with the ARDS net strategy. In these patients, rescue therapies such as high-frequency ventilation, prone ventilation, nitric oxide, and extracorporeal membrane oxygenation (ECMO) are considered. The CESAR trial has shown that an ECMO-based protocol improved survival without severe disability as compared with conventional ventilation. The recent increased incidence of severe respiratory failure due to H1N1 influenza pandemic has led to an increased use of ECMO. Although several reports showed ECMO use to be encouraging, some scepticism remains. In this article, we reviewed the usefulness of ECMO in patients with severe ARDS in the light of current evidence.     

Do we need randomized clinical trials in extracorporeal respiratory support? Yes

Extracorporeal respiratory support, also known as extracorporeal gas exchange, may be used to rescue the most severe forms of acute hypoxemic respiratory failure with high blood flow venovenous extracorporeal membrane oxygenation. Alternatively, lower flow extracorporeal carbon dioxide removal might be applied to reduce the intensity of mechanical ventilation in patients with less severe forms of the disease. However, critical reading of the results of the randomized trials and case series published to date reveals major methodological biases. Older trials are not relevant anymore since the ECMO circuitry was not heparin-coated leading to severe hemorrhagic complications due to high levels of anticoagulation, and because extracorporeal membrane oxygenation (ECMO) and control group patients did not receive lung-protective ventilation. Alternatively, in the more recent CESAR trial, many patients randomized to the ECMO arm did not receive ECMO and no standardized protocol for lung-protective mechanical ventilation existed in the control group. Since these techniques are costly and associated with potentially serious adverse events, there is an urgent need for high-quality data, for which the cornerstone remains randomized controlled trials.     

Extracorporeal membrane oxygenation for severe respiratory failure in adult patients: A systematic review and meta-analysis of current evidence

Background

Extracorporeal membrane oxygenation (ECMO) for acute respiratory failure is still a matter of debate.

Methods

We performed a structured search on Pubmed, EMBASE, Lilacs, and the Cochrane Library for randomized controlled trials and observational case-control studies with severity-paired patients, evaluating the use of ECMO on severe acute respiratory failure in adult patients. A random-effect model using DerSimonian and Laird method for variance estimator was performed to evaluate the effect of ECMO use on hospital mortality. Heterogeneity between studies was assessed with Cochran's Q statistic and Higgin's I².

Results

Three studies were included on the metanalysis, comprising 353 patients in the main analysis, in which 179 patients were ECMO supported. One study was a randomized controlled trial and two were observational studies with a propensity score matching. The most common reason for acute respiratory failure was influenza H1N1 pneumonia (45%) and pneumonia (33%). ECMO was not associated with a reduction in hospital mortality (OR = 0.71; CI 95% = 0.34 - 1.47; P = 0.358). If alternative severity-pairing method presented by the two observational studies was included, a total of 478 cases were included, in which 228 received ECMO support. In the former analysis, ECMO had a benefit on hospital mortality (OR = 0.52; CI 95% = 0.35 - 0.76; P < 0.001).

Conclusion

Extracorporeal membrane oxygenation benefit on hospital mortality is unclear. Results were sensitive to statistical analysis, and no definitive conclusion can be drawn from the available data. More studies are needed before the widespread use of ECMO can be recommended.     

Extracorporeal gas exchange in acute lung injury: step by step towards expanded indications?

Extracorporeal membrane oxygenation (ECMO) is widely accepted as a rescue therapy in patients with acute life-threatening hypoxemia in the course of severe acute respiratory distress syndrome (ARDS). However, possible side effects and complications are considered to limit beneficial outcome effects. Therefore, widening indications with the aim of reducing ventilator induced lung injury (VILI) is still controversial. Consequently, technological progress is an important strategy. Miniaturized ECMO systems are believed to simplify handling and reduce side effects and complications. Mueller and co-workers evaluated such a small-sized device in 60 patients with severe ARDS. They accomplished both the treatment of severe hypoxemia and reduction of VILI, demonstrating feasibility, a moderate rate of severe complications, and a 45% intensive care survival rate. Although neither randomized nor controlled, this study should encourage others to implement such systems in clinical practice. From a strategic perspective, this is another small but useful step towards implementing extracorporeal gas exchange for the prevention of VILI. It is already common sense that the prevention of acute life-threatening hypoxemia usually outweighs the risks of this technique. The next step should be to prove that prevention of life-threatening VILI balances the risks too.     

Role of corticosteroids in the management of acute respiratory distress syndrome

BACKGROUND: Evidence exploring the use of corticosteroids for acute respiratory distress syndrome (ARDS) has targeted various stages of disease progression, from preventing ARDS in high-risk patients to halting disease evolution once ARDS has developed. OBJECTIVE: The aim of this review was to evaluate randomized, controlled trials describing the role of corticosteroids in preventing and treating ARDS. METHODS: English-language randomized, controlled trials were identified using MEDLINE via PubMed and EMBASE searches (key terms: acute respiratory distress syndrome, acute lung injury, and corticosteroids; years: 1968-January 2008). RESULTS: A total of 10 trials were found and included in this analysis. Trials describing the role of high-dose corticosteroids compared with controls in preventing ARDS found no benefit, with the range of occurrence of ARDS in at-risk populations from 14% to 64% and absolute increases in mortality from 4% to 31%. Conflicting evidence was found for treating late-phase ARDS with corticosteroids, with 13% hospital mortality among patients receiving corticosteroids versus 63% with controls (P = 0.03) in one small study, but no significant difference was found when evaluating 60-day mortality (corticosteroid group, 29.2% vs control, 28.6%) in another investigation. The use of high-dose corticosteroids for the treatment of early phase ARDS was not associated with significant differences in 45-day mortality (methylprednisolone, 60% vs control, 63%). However, one trial found that methylprednisolone taper for early ARDS was associated with significant improvement in lung function or extubation (69.8% vs 35.7%; P = 0.002), fewer days on mechanical ventilation (median, 5.0 vs 9.5; P = 0.002), higher intensive care unit survival (79.4% vs 57.4%; P = 0.03), but similar rates of hospital survival (methylprednisolone, 76.2% vs control, 57.1%; P = NS). CONCLUSIONS: Data from clinical trials did not support the use of short-course, high-dose corticosteroids for preventing ARDS or for the treatment of early ARDS. Longer-course corticosteroids have not conclusively been associated with improved survival in the treatment of late-phase ARDS but have provided some benefits in other markers of disease severity in this setting and in early phase ARDS. Published trials support the administration of low- to moderate-dose corticosteroids in the treatment of early (<7 days) and late-phase (days 7\2-14) ARDS, but this evidence is controversial.     

Effects of interventions on survival in acute respiratory distress syndrome: an umbrella review of 159 published randomized trials and 29 meta-analyses

Purpose

Multiple interventions have been tested in acute respiratory distress syndrome (ARDS). We examined the entire agenda of published randomized controlled trials (RCTs) in ARDS that reported on mortality and of respective meta-analyses.

Methods

We searched PubMed, the Cochrane Library, and Web of Knowledge until July 2013. We included RCTs in ARDS published in English. We excluded trials of newborns and children; and those on short-term interventions, ARDS prevention, or post-traumatic lung injury. We also reviewed all meta-analyses of RCTs in this field that addressed mortality. Treatment modalities were grouped in five categories: mechanical ventilation strategies and respiratory care, enteral or parenteral therapies, inhaled/intratracheal medications, nutritional support, and hemodynamic monitoring.

Results

We identified 159 published RCTs of which 93 had overall mortality reported (n = 20,671 patients)—44 trials (14,426 patients) reported mortality as a primary outcome. A statistically significant survival benefit was observed in eight trials (seven interventions) and two trials reported an adverse effect on survival. Among RCTs with more than 50 deaths in at least one treatment arm (n = 21), two showed a statistically significant mortality benefit of the intervention (lower tidal volumes and prone positioning), one showed a statistically significant mortality benefit only in adjusted analyses (cisatracurium), and one (high-frequency oscillatory ventilation) showed a significant detrimental effect. Across 29 meta-analyses, the most consistent evidence was seen for low tidal volumes and prone positioning in severe ARDS.

Conclusions

There is limited supportive evidence that specific interventions can decrease mortality in ARDS. While low tidal volumes and prone positioning in severe ARDS seem effective, most sporadic findings of interventions suggesting reduced mortality are not corroborated consistently in large-scale evidence including meta-analyses.     

Prone position: the time of certainty

After four negative randomized controlled trials testing the effects of prone positioning on patient outcome, a fifth randomized controlled trial (PROSEVA trial) has been able to show a significant reduction in mortality in patients with acute respiratory distress syndrome (ARDS). In this trial including patients with ARDS severity criteria (PaO₂/FiO₂ ratio less than 150 mmHg with positive end expiratory pressure of 5 cmH₂O or more, FiO₂ of 0.6 or more, and tidal volume around 6 ml/kg of predicted body weight) confirmed 12 to 24 h after the onset of ARDS, the day 28 mortality in the supine group (229 patients) was 32.8% versus 16% in the prone group (237 patients) (p < 0.001). The same significant reduction in mortality was confirmed at day 90. The reasons for this result that contrasted with the previous ones as well as the refinements that were introduced in the trials over time are discussed in this review article. From the results of the two meta-analyses and the last randomized controlled trial, there is a strong signal to use prone position in patients suffering from ARDS with severity criteria. More data are needed about the effects of prone position on ventilation-induced lung injury in humans.