title: The effectiveness of avalanche airbags.
abstract: OBJECTIVE
  Asphyxia is the primary cause of death among avalanche victims. Avalanche airbags can lower mortality by directly reducing grade of burial, the single most important factor for survival. This study aims to provide an updated perspective on the effectiveness of this safety device.
  
  
  METHODS
  A retrospective analysis of avalanche accidents involving at least one airbag user between 1994 and 2012 in Austria, Canada, France, Norway, Slovakia, Switzerland and the United States. A multivariate analysis was used to calculate adjusted absolute risk reduction and estimate the effectiveness of airbags on grade of burial and mortality. A univariate analysis was used to examine causes of non-deployment.
  
  
  RESULTS
  Binomial linear regression models showed main effects for airbag use, avalanche size and injuries on critical burial, and for grade of burial, injuries and avalanche size on mortality. The adjusted risk of critical burial is 47% with non-inflated airbags and 20% with inflated airbags. The adjusted mortality is 44% for critically buried victims and 3% for non-critically buried victims. The adjusted absolute mortality reduction for inflated airbags is -11 percentage points (22% to 11%; 95% confidence interval: -4 to -18 percentage points) and adjusted risk ratio is 0.51 (95% confidence interval: 0.29 to 0.72). Overall non-inflation rate is 20%, 60% of which is attributed to deployment failure by the user.
  
  
  CONCLUSIONS
  Although the impact on survival is smaller than previously reported, these results confirm the effectiveness of airbags. Non-deployment remains the most considerable limitation to effectiveness. Development of standardized data collection protocols is encouraged to facilitate further research.
authors.affiliation: Avisualanche Consulting, 2-250 E 15th Avenue, Vancouver, BC, V5T 2P9, Canada; School for Resource and Environmental Management, Simon Fraser University, 8888 University Drive, Burnaby, BC, V5A 1S6, Canada. Electronic address: pascal@avisualanche.ca.
authors.forename: Pascal
authors.initials: P
authors.lastname: Haegeli
authors.affiliation: Inova Q Inc., Tinkhauserstrasse 5b, 39031 Bruneck/Brunico, Italy.
authors.forename: Markus
authors.initials: M
authors.lastname: Falk
authors.affiliation: EURAC Institute of Mountain Emergency Medicine, Drususallee 1, 39100 Bozen/Bolzano, Italy.
authors.forename: Emily
authors.initials: E
authors.lastname: Procter
authors.affiliation: WSL Institute for Snow and Avalanche Research SLF, Flüelastrasse 11, 7260 Davos, Switzerland.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Zweifel
authors.affiliation: National Association for Snow and Avalanche Studies (ANENA), 15 rue Ernest Calvat, 38000 Grenoble, France.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Jarry
authors.affiliation: Colorado Avalanche Information Center, 325 Broadway WS1, Boulder, CO 80305, USA.
authors.forename: Spencer
authors.initials: S
authors.lastname: Logan
authors.affiliation: Norwegian Geotechnical Institute (NGI), Sognsveien 72, N-0855 Oslo, Norway.
authors.forename: Kalle
authors.initials: K
authors.lastname: Kronholm
authors.affiliation: Avalanche Prevention Center, Jasná, 032 51 Demänovská Dolina, Slovakia; Institute for Environmental Studies, Charles University, Ovocný trh 3-5, 116 36 Praha 1, Czech Republic.
authors.forename: Marek
authors.initials: M
authors.lastname: Biskupič
authors.affiliation: EURAC Institute of Mountain Emergency Medicine, Drususallee 1, 39100 Bozen/Bolzano, Italy.
authors.forename: Hermann
authors.initials: H
authors.lastname: Brugger
mesh_terms: D017278:Air Bags; D001237:Asphyxia / Q000401:mortality* / Q000517:prevention & control*; D055875:Avalanches; D006801:Humans; D015999:Multivariate Analysis; D012189:Retrospective Studies
keywords: Avalanche accidents; Burial prevention; Mortality; Safety equipment