Lung protective ventilation strategy for the acute respiratory distress syndrome

  • Review
  • Intervention

Authors


Abstract

Background

Patients with acute respiratory distress syndrome and acute lung injury require mechanical ventilatory support. Acute respiratory distress syndrome and acute lung injury are further complicated by ventilator-induced lung injury. Lung protective ventilation strategies may lead to improved survival. This systematic review is an update of a Cochrane review originally published in 2003 and updated in 2007.

Objectives

To assess the effects of ventilation with lower tidal volume on morbidity and mortality in patients aged 16 years or older affected by acute respiratory distress syndrome and acute lung injury. A secondary objective was to determine whether the comparison between low and conventional tidal volume was different if a plateau airway pressure of greater than 30 to 35 cm H20 was used.

Search methods

In our previous 2007 updated review, we searched databases from inception until 2006. In this third updated review, we searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, CINAHL and the Web of Science from 2006 to September 2012. We also updated our search of databases of ongoing research and of reference lists from 2006 to September 2012.

Selection criteria

We included randomized controlled trials comparing ventilation using either a lower tidal volume (Vt) or low airway driving pressure (plateau pressure 30 cm H2O or less), resulting in a tidal volume of 7 ml/kg or less, versus ventilation that used Vt in the range of 10 to 15 ml/kg in adults (16 years old or older) with acute respiratory distress syndrome and acute lung injury.

Data collection and analysis

We independently assessed trial quality and extracted data. Wherever appropriate, results were pooled. We applied fixed-effect and random-effects models.

Main results

We did not find any new study which were eligible for inclusion in this update. The total number of studies remained unchanged, six trials involving 1297 patients. Five trials had a low risk of bias. One trial had an unclear risk of bias. Mortality at day 28 was significantly reduced by lung-protective ventilation with a relative risk (RR) of 0.74 (95% confidence interval (CI) 0.61 to 0.88); hospital mortality was reduced with a RR of 0.80 (95% CI 0.69 to 0.92). Overall mortality was not significantly different if a plateau pressure less than or equal to 31 cm H2O in the control group was used (RR 1.13, 95% CI 0.88 to 1.45). There was insufficient evidence for morbidity and long-term outcomes.

Authors' conclusions

Clinical heterogeneity, such as different lengths of follow up and higher plateau pressure in control arms in two trials, makes the interpretation of the combined results difficult. Mortality was significantly reduced at day 28 and at the end of the hospital stay. The effects on long-term mortality are unknown, although the possibility of a clinically relevant benefit cannot be excluded. Ventilation with lower tidal volumes is becoming a routine strategy of treatment of acute respiratory distress syndrome and acute lung injury, stopping investigators from carrying out additional trials.

摘要

肺部防护通气策略治疗急性呼吸窘迫综合征

研究背景

急性呼吸窘迫综合征和急性肺损伤患者均需要机械通气支持。急性呼吸窘迫综合征和急性肺损伤由呼吸机诱导的肺损伤进一步复杂化。肺保护通气策略可能导致生存率的提高。该系统综述是最初于2003年发表并于2007年更新的Cochrane综述的再次更新版本。

研究目的

评价潮气量较低的通气对急性呼吸窘迫综合征和急性肺损伤16岁及以上患者的发病率和死亡率的影响。第二个目的是确定如果使用大于30至35厘米水柱的平台气道压力,低和常规潮气量之间是否不同。

检索策略

在我们以前的2007年更新的综述中,我们从建库开始检索到2006年。在第三次更新的综述中,我们检索了2006年至2012年9月期间Cochrane对照试验中心(CENTRAL),MEDLINE,EMBASE,CINAHL和科学网。我们还更新了我们从2006年至2012年9月期间对正在进行的研究数据库和引文的检索。

标准/纳入排除标准

我们纳入了干预使用低潮气量(Vt)或低气道驱动压力(平台压力30cm水柱或更低)使潮气量为7ml / kg或更低,对照使用Vt在10至15 ml / kg范围内的通气治疗成人(16岁或以上)急性呼吸窘迫综合征和急性肺损伤的随机对照试验。

数据收集与分析

我们独立评估试验质量并提取数据。适当地综合数据。应用固定效应模型和随机效应模型

主要结果

本次更新我们没有找到任何符合纳入条件的新研究。研究总数保持不变,6项试验涉及1297例。5项试验偏倚风险偏低。一项试验有不明确的偏倚风险。肺保护通气在第28天的死亡率明显降低,相对风险(RR)为0.74(95%置信区间(CI)0.61〜0.88);住院死亡率降低,RR为0.80(95%CI为0.69至0.92)。如果对照组使用的平均血压小于或等于31厘米水柱,总死亡率没有显着差异(RR=1.13, 95%CI=0.88〜1.45)。发病率和长期结局方面没有足够证据。

作者结论

临床异质性,例如两项试验组间随访时间长度不同或较高的平台压,使数据综合后结果的解释变困难。在第28天和住院结束时,死亡率明显下降。对长期死亡率的疗效是未知的,尽管不能排除具有临床相关益处的可能性。潮气量较低的通气已成为治疗急性呼吸窘迫综合征和急性肺损伤的常规策略,研究人员已不须进行额外的试验。

翻译注解

译者:李文元,审校:鲁春丽。北京中医药大学循证医学中心。2017年9月3日。

Plain language summary

A gentler form of mechanical breathing for people affected by severe lung failure

Critically ill people affected by severe, acute respiratory failure need air to be pumped into their lungs (mechanical ventilation) to survive. Mechanical support buys time for the lungs to heal. Nevertheless, 35% to 65% still die. Several studies have suggested that mechanical breathing can also cause lung damage and bleeding. A new lung protective way of mechanical ventilation was tested in large studies. In this third update of the Cochrane review we searched the databases until September 2012 but we did not find any new study which was eligible for inclusion. The total number of studies remained unchanged, six trials involving 1297 people. This systematic review shows that a gentler form of mechanical breathing (so-called protective ventilation) can decrease deaths in the short term, by 26% on average, but the effects in the long term are uncertain or unknown.

概要

一种温和的机械呼吸形式治疗严重肺衰竭患者

受严重急性呼吸衰竭影响的危重病人需要将空气泵入肺部(机械通气)才能存活。机械支持为肺而赢得时间以获得治愈。然而,仍有35%至65%的人死亡。几项研究表明,机械呼吸也可能导致肺部损伤和出血。在大型研究中测试了一种新的机械通气肺保护方法。在本篇Cochrane系统综述的第三次更新中,我们检索数据库到2012年9月,但是我们没有发现任何能纳入的新研究。研究总数保持不变,六项试验涉及1297人。本篇系统综述显示,一种更温和的机械呼吸形式(所谓保护性通气)可以使短期内的死亡人数平均减少26%,但长期疗效是不确定或未知的。

翻译注解

译者:李文元,审校:鲁春丽。北京中医药大学循证医学中心。2017年9月3日。

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