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Meta-Analysis
. 2014 Mar;40(3):332-41.
doi: 10.1007/s00134-013-3194-3. Epub 2014 Jan 17.

Prone positioning reduces mortality from acute respiratory distress syndrome in the low tidal volume era: a meta-analysis

Jeremy R Beitler  1 , Shahzad Shaefi, Sydney B Montesi, Amy Devlin, Stephen H Loring, Daniel Talmor, Atul Malhotra
Affiliations
Meta-Analysis

Prone positioning reduces mortality from acute respiratory distress syndrome in the low tidal volume era: a meta-analysis

Jeremy R Beitler et al. Intensive Care Med. 2014 Mar.

Abstract

Purpose: Prone positioning for ARDS has been performed for decades without definitive evidence of clinical benefit. A recent multicenter trial demonstrated for the first time significantly reduced mortality with prone positioning. This meta-analysis was performed to integrate these findings with existing literature and test whether differences in tidal volume explain conflicting results among randomized trials.

Methods: Studies were identified using MEDLINE, EMBASE, Cochrane Register of Controlled Trials, LILACS, and citation review. Included were randomized trials evaluating the effect on mortality of prone versus supine positioning during conventional ventilation for ARDS. The primary outcome was risk ratio of death at 60 days meta-analyzed using random effects models. Analysis stratified by high (>8 ml/kg predicted body weight) or low (≤ 8 ml/kg PBW) mean baseline tidal volume was planned a priori.

Results: Seven trials were identified including 2,119 patients, of whom 1,088 received prone positioning. Overall, prone positioning was not significantly associated with the risk ratio of death (RR 0.83; 95% CI 0.68-1.02; p = 0.073; I (2) = 64%). When stratified by high or low tidal volume, prone positioning was associated with a significant decrease in RR of death only among studies with low baseline tidal volume (RR 0.66; 95% CI 0.50-0.86; p = 0.002; I (2) = 25%). Stratification by tidal volume explained over half the between-study heterogeneity observed in the unstratified analysis.

Conclusions: Prone positioning is associated with significantly reduced mortality from ARDS in the low tidal volume era. Substantial heterogeneity across studies can be explained by differences in tidal volume.

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Conflict of interest statement

Conflicts of interest On behalf of all authors, the corresponding author states that there is no conflict of interest.

Figures

Fig. 1
Fig. 1
Literature search strategy and study selection
Fig. 2
Fig. 2
Effect of prone positioning on mortality, overall and stratified by mean baseline tidal volume. High tidal volume was defined as >8 ml/kg predicted body weight and low tidal volume as ≤8 ml/kg predicted body weight
Fig. 3
Fig. 3
Cumulative meta-analysis forest plot over time, demonstrating a trend favoring prone positioning with inclusion of each successive study
See this image and copyright information in PMC

References

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