title: Effect of prone positioning in patients with acute respiratory distress syndrome: a meta-analysis.
abstract: OBJECTIVE
  To review the effectiveness of prone position as compared with supine position, with respect to mortality, improvement in oxygenation, number of days on mechanical ventilation, and ventilator-associated pneumonia.
  
  
  METHODS
  PubMed, EMBASE, Cochrane database, and a manual review of article bibliographies.
  
  
  METHODS
  Randomized controlled trials comparing > or = 6 hrs of prone position with supine position in adult patients with adult respiratory distress syndrome.
  
  
  METHODS
  Two reviewers independently performed assessment of abstracts and study quality. Data were combined in a meta-analysis using random-effect models.
  
  
  RESULTS
  Five studies were identified. We did not find any significant differences in intensive care unit mortality (three studies, 466 patients; odds ratio, 0.79; 95% confidence interval [CI], 0.45-1.39), 28- to 30-day mortality (three studies, 1,231 patients; odds ratio, 0.95; 95% CI, 0.71-1.28), and 90-day mortality (four studies, 1,271 patients; odds ratio, 0.99; 95% CI, 0.77-1.27). However, prone position showed significant reduction in mortality in patients with higher illness severity (two studies, 113 patients; odds ratio, 0.29; 95% CI, 0.12-0.70). Prone positioning also showed significant and persistent improvement in the PaO2/FiO2 ratio in early (12 hrs to 2 days) (four studies, 866 patients; weighted mean difference, 51.5; 95% CI, 6.95-96.05), intermediate (4 days) (three studies, 754 patients; weighted mean difference, 43.87; 95% CI, 13.86-73.88), and late (10 days) period (four studies, 833 patients; weighted mean difference, 24.89; 95% CI, 15.3-34.48). There were no significant differences in number of days on mechanical ventilation (two studies, 831 patients; weighted mean difference, -0.42 days; 95% CI, -1.56 to 0.72) or incidence of ventilator-associated pneumonia (three studies, 967 patients; weighted mean difference, 0.78%; 95% CI, 0.40-1.51).
  
  
  CONCLUSIONS
  Based on the results of this meta-analysis, prone position improves oxygenation in patients with adult respiratory distress syndrome, and in patients with higher illness severity, it also may reduce mortality.
authors.affiliation: Division of Critical Care, Department of Medicine, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada.
authors.forename: Abdullah H
authors.initials: AH
authors.lastname: Alsaghir
authors.forename: Claudio M
authors.initials: CM
authors.lastname: Martin
mesh_terms: D000328:Adult; D006801:Humans; D010101:Oxygen Consumption / Q000502:physiology; D053717:Pneumonia, Ventilator-Associated / Q000453:epidemiology; D016684:Prone Position; D012121:Respiration, Artificial; D012128:Respiratory Distress Syndrome / Q000378:metabolism / Q000401:mortality / Q000628:therapy*