The effect of prone positioning on mortality in patients with acute respiratory distress syndrome: a meta-analysis of randomized controlled trials

Abstract

IntroductionProne positioning (PP) has been reported to improve the survival of patients with severe acute respiratory distress syndrome (ARDS). However, it is uncertain whether the beneficial effects of PP are associated with positive end-expiratory pressure (PEEP) levels and long durations of PP. In this meta-analysis, we aimed to evaluate whether the effects of PP on mortality could be affected by PEEP level and PP duration and to identify which patients might benefit the most from PP.MethodsPublications describing randomized controlled trials (RCTs) in which investigators have compared prone and supine ventilation were retrieved by searching the following electronic databases: PubMed/MEDLINE, the Cochrane Library, the Web of Science and Elsevier Science (inception to May 2013). Two investigators independently selected RCTs and assessed their quality. The data extracted from the RCTs were combined in a cumulative meta-analysis and analyzed using methods recommended by the Cochrane Collaboration.ResultsA total of nine RCTs with an aggregate of 2,242 patients were included. All of the studies received scores of up to three points using the methods recommended by Jadad et al. One trial did not conceal allocation. This meta-analysis revealed that, compared with supine positioning, PP decreased the 28- to 30-day mortality of ARDS patients with a ratio of partial pressure of arterial oxygen/fraction of inspired oxygen ≤100 mmHg (n = 508, risk ratio (RR) = 0.71, 95 confidence interval (CI) = 0.57 to 0.89; P = 0.003). PP was shown to reduce both 60-day mortality (n = 518, RR = 0.82, 95% CI = 0.68 to 0.99; P = 0.04) and 90-day mortality (n = 516, RR = 0.57, 95% CI = 0.43 to 0.75; P < 0.0001) in ARDS patients ventilated with PEEP ≥10 cmH2O. Moreover, PP reduced 28- to 30-day mortality when the PP duration was >12 h/day (n = 1,067, RR = 0.73, 95% CI = 0.54 to 0.99; P = 0.04).ConclusionsPP reduced mortality among patients with severe ARDS and patients receiving relatively high PEEP levels. Moreover, long-term PP improved the survival of ARDS patients.

Efficacy of prone position in acute respiratory distress syndrome: overview of systematic reviews

“…Table 1 demonstrates the most significant relative risk was found for the 60-day hospitalization period in the conditions under study (18) . Statistical significance for the reduction of mortality from prone positioning was verified in six out of the 11 studies included, especially in those in which protective ventilation was used (19) .…”

“…The search for relevant studies in gray literature was not contained in the inclusion criteria of three systematic reviews (17)(18)23) . Six studies did not state the conflicts of interest (17)(18)(19)(20)(22)(23) .…”

“…The early use of prone position during ventilatory support for severe acute respiratory distress syndrome in patients requiring relatively high PEEP levels and reduced tidal volumes is associated with the best physiological response of collapsed alveolar units. As these units are more susceptible to be open (alveolar recruitment) during the initial phase of disease (exudative), it implies on a significant reduction in mortality (14,18,23) . Another relevant aspect of using the prone position refers to the analysis of the subgroup 'PaO2/FiO2 ratio' that indicated a significant reduction in the additional mortality rate in patients with severe hypoxemia or other severe clinical conditions associated (14) .…”

“…This leads to the conclusion that the systematic reviews included have high scientific rigor when assessing the maximum AMSTAR score (11 points). Considering the elements of the AMSTAR measuring tool, all the included studies described the following: clinical question and inclusion criteria; selection and data extraction by peers; conduction of a comprehensive literature survey; list of studies (included and excluded); characteristics of the included studies; assessment of the scientific quality of included studies; the use of the scientific quality of studies in the formulation of conclusions; appropriate combination of study results; risk assessment of bias.The search for relevant studies in gray literature was not contained in the inclusion criteria of three systematic reviews (17)(18)23) . Six studies did not state the conflicts of interest (17)(18)(19)(20)(22)(23) .…”

Rescue Strategies in Severe Refractory Hypoxemic Respiratory Failure: Taking a Step Back

“…Subsequent meta-analyses have confirmed these findings and additionally suggested that the improved survival from prone positioning is only observed when combined with low tidal volume and high levels of PEEP ventilation. 14 The OSCAR trial, 15 a multicenter randomized study, documented that the use of highfrequency oscillatory ventilation had no significant effect on 30-d mortality in subjects undergoing mechanical ventilation for ARDS.…”