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The Efficacy and Safety of Prone Positional Ventilation in Acute Respiratory Distress Syndrome: Updated Study-Level Meta-Analysis of 11 Randomized Controlled Trials*

Lee, Joo Myung MD, MPH1; Bae, Won MD2; Lee, Yeon Joo MD2; Cho, Young-Jae MD, MPH2

doi: 10.1097/CCM.0000000000000122
Review Articles

Objective: The survival benefit of prone positioning during mechanical ventilation for acute respiratory distress syndrome has been a matter of debate. Recent multicenter randomized controlled trials have shown a significant reduction of 28-day and 90-day mortality associated with prone positioning during mechanical ventilation for severe acute respiratory distress syndrome. We performed an up-to-date meta-analysis on this topic and elucidated the effect of prone positioning on overall mortality and associated complications.

Data Sources: PubMed, EMBASE, BioMed Central, Cochrane Central Register of Controlled Trials,, and conference proceedings through May 2013.

Study Selection: Randomized controlled trial comparing overall mortality of prone-versus-supine positioning in patients with acute respiratory distress syndrome.

Data Extraction: Data were extracted for populations, interventions, outcomes, and risk of bias. The prespecified primary endpoint was overall mortality, using the longest available follow-up in each study. The odds ratio with 95% CI was the effect measure.

Data Synthesis: This analysis included 11 randomized controlled trial, 2,246 total adult patients, and 1,142 patients ventilated in the prone position. Prone positioning during ventilation significantly reduced overall mortality in the random-effect model (odds ratio, 0.77; 95% CI, 0.59–0.99; p = 0.039; I 2 = 33.7%), and the effects were marked in the subgroup in which the duration of prone positioning was more than 10 hr/session, compared with the subgroup with a short-term duration of prone positioning (odds ratio, 0.62; 9% CI, 0.48–0.79; p = 0.039; p interaction = 0.015). Prone positioning was significantly associated with pressure ulcers (odds ratio, 1.49; 95% CI, 1.18–1.89; p = 0.001; I 2 = 0.0%) and major airway problems (odds ratio, 1.55; 95% CI, 1.10–2.17; p = 0.012; I 2 = 32.7%).

Conclusions: Ventilation in the prone position significantly reduced overall mortality in patients with severe acute respiratory distress syndrome. Sufficient duration of prone positioning was significantly associated with a reduction in overall mortality. Prone ventilation was also significantly associated with pressure ulcers and major airway problems.

Supplemental Digital Content is available in the text.

1Division of Cardiology, Department of Internal Medicine and Cardiovascular Center, Seoul National University Hospital, Seoul, Korea.

2Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, Korea.

* See also p. 1318.

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The authors have disclosed that they do not have any potential conflicts of interest.

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© 2014 by the Society of Critical Care Medicine and Lippincott Williams & Wilkins