title: Predicting outcome of drowning at the scene: A systematic review and meta-analyses.
abstract: To identify factors available to rescuers at the scene of a drowning that predict favourable outcomes.
  
  
  
  Systematic review and meta-analysis.
  
  
  
  PubMed, Embase and Cochrane Library were searched (1979-2015) without restrictions on age, language or location and references lists of included articles.
  
  
  
  Cohort and case-control studies reporting submersion duration, age, water temperature, salinity, emergency services response time and survival and/or neurological outcomes were eligible. Two reviewers independently screened articles for inclusion, extracted data, and assessed quality using GRADE. Variables for all factors, including time and temperature intervals, were categorized using those used in the articles. Random effects meta-analyses, study heterogeneity and publication bias were evaluated.
  
  
  
  Twenty-four cohort studies met the inclusion criteria. The strongest predictor was submersion duration. Meta-analysis showed that favourable outcome was associated with shorter compared to longer submersion durations in all time cutoffs evaluated: ≤5-6min: risk ratio [RR]=2.90; (95% confidence interval [CI]: 1.73, 4.86); ≤10-11min: RR=5.11 (95% CI: 2.03, 12.82); ≤15-25min: RR=26.92 (95% CI: 5.06, 143.3). Favourable outcomes were seen with shorter EMS response times (RR=2.84 (95% CI: 1.08, 7.47)) and salt water versus fresh water 1.16 (95% CI: 1.08, 1.24). No difference in outcome was seen with victim's age, water temperatures, or witnessed versus unwitnessed drownings.
  
  
  
  Increasing submersion duration was associated with worse outcomes. Submersion durations <5min were associated with favourable outcomes, while those >25min were invariably fatal. This information may be useful to rescuers and EMS systems deciding when to perform a rescue versus a body recovery.
authors.affiliation: Department of Pediatrics, University of Washington School of Medicine, 1959 NE Pacific St, Seattle, WA 98195, USA; Seattle Children's Hospital, 4800 Sand Point Way NE, Seattle, WA 98145, USA; Harborview Injury Prevention & Research Center, 401 Broadway, University of Washington, Seattle, WA 98122, USA. Electronic address: linda.quan@seattlechildrens.org.
authors.forename: Linda
authors.initials: L
authors.lastname: Quan
authors.affiliation: Research Group Emergency and Disaster Medicine, Vrije Universiteit Brussels, Pleinlaan 2, 1050 Elsene, Belgium.
authors.forename: Joost J L M
authors.initials: JJ
authors.lastname: Bierens
authors.affiliation: Department of Epidemiology, School of Public Health, 1959 NE Pacific St, Seattle, WA 98195, USA.
authors.forename: Rebecca
authors.initials: R
authors.lastname: Lis
authors.affiliation: Harborview Injury Prevention & Research Center, 401 Broadway, University of Washington, Seattle, WA 98122, USA; Department of Epidemiology, School of Public Health, 1959 NE Pacific St, Seattle, WA 98195, USA.
authors.forename: Ali
authors.initials: A
authors.lastname: Rowhani-Rahbar
authors.affiliation: Royal Melbourne Hospital Clinical School, University of Melbourne, Grattan Street, Parkville, Victoria 3050, Australia.
authors.forename: Peter
authors.initials: P
authors.lastname: Morley
authors.affiliation: Warwick Medical School, University of Warwick, Coventry CV4 7AL, UK; Heart of England NHS Foundation Trust, Bordesley Green East, Birmingham B9 5SS, UK.
authors.forename: Gavin D
authors.initials: GD
authors.lastname: Perkins
mesh_terms: D016022:Case-Control Studies; D015331:Cohort Studies; D004332:Drowning / Q000401:mortality*; D004632:Emergency Medical Services; D006801:Humans; D013997:Time Factors
keywords: Age; Drowning; EMS system; Prognosis; Submersion duration; Water temperature