Resuscitation 105 (2016) 173–176 Contents lists available at ScienceDirect Resuscitation jou rn al hom ep age : w ww.elsevier.com/locate/resuscitation Clinical paper Burial duration, depth and air pocket explain avalanche survival patterns in Austria and Switzerland  Emily Procter a,b , Giacomo Strapazzon a,* , Tomas Dal Cappello a , Benjamin Zweifel c , Andreas Würtele d , Andreas Renner a , Markus Falk a,e , Hermann Brugger a a EURAC Institute of Mountain Emergency Medicine, Viale Druso 1, 39100 Bolzano, Italy b Department of Sport Science, University of Innsbruck, Fürstenweg 185, 6020 Innsbruck, Austria c WSL Institute for Snow and Avalanche Research SLF, Flüelastrasse 11, 7260 Davos, Switzerland d Austrian Board of Alpine Safety, Olympiastrasse 10, 6020 Innsbruck, Austria e Inova Q Inc. , Tinkhauserstrasse 5b, 39031 Brunico, Italy a r t i c l e i n f o Article history: Received 16 February 2016 Received in revised form 7 May 2016 Accepted 4 June 2016 Keywords: Survival probability Survival curve Avalanche Burial depth Asphyxia a b s t r a c t Aim: To calculate the first Austrian avalanche survival curve and update a Swiss survival curve to explore survival patterns in the Alps. Methods: Avalanche accidents occurring between 2005/06 and 2012/13 in Austria and Switzerland were collected. Completely buried victims (i.e. burial of the head and chest) in open terrain with known out- come (survived or not survived) were included in the analysis. Extrication and survival curves were calculated using the Turnbull algorithm, as in previous studies. Results: 633 of the 796 completely buried victims were included (Austria n = 333, Switzerland n = 300). Overall survival was 56% (Austria 59%; Switzerland 52%; p = 0.065). Time to extrication was shorter in Austria for victims buried ≤60 min (p < 0.001). The survival curves were similar and showed a rapid initial drop in survival probability and a second drop to 25–28% survival probability after burial duration of ca. 35 min, where an inflection point exists and the curve levels off. In a logistic regression analysis, both duration of burial and burial depth had an independent effect on survival. Victims with an air pocket were more likely to survive, especially if buried >15 min. Conclusion: The survival curves resembled those previously published and support the idea that underly- ing survival patterns are reproducible. The results are in accordance with current recommendations for management of avalanche victims and serve as a reminder that expedient companion rescue within a few minutes is critical for survival. An air pocket was shown to be a positive prognostic factor for survival. © 2016 Elsevier Ireland Ltd. All rights reserved. Introduction An avalanche survival curve is a graphical representation of the cumulative survival probability during complete avalanche burial as a function of time. 1 The step-wise decrease of survival prob- ability with increasing duration of burial was first recognized in the original curve in 1994 using avalanche data from Switzerland. 1 Four distinct phases could be distinguished in the curve, which reflected patterns of death in victims extricated within that time period: trauma is the major cause of death in the first (“sur- vival”) phase, asphyxia in the second (“asphyxia”) phase and a  A Spanish translated version of the summary of this article appears as Appendix in the final online version at http://dx.doi.org/10.1016/j.resuscitation.2016.06.001. * Corresponding author at: Institute of Mountain Emergency Medicine, EURAC Research, Viale Druso 1, I-39100 Bozen/Bolzano, Italy. E-mail address: giacomo.strapazzon@eurac.edu (G. Strapazzon). combination of severe hypothermia, hypoxia and hypercapnia in the third (“latent”) and fourth (“long-term survival”) phases. Cha- racterising avalanche survival in this manner had a lasting practical impact on avalanche rescue. For example, these curves offered a way to quantify the importance of rapid extrication by compan- ion rescuers, i.e. a victim must be extricated within ca. 15 min for a survival chance of >90%. Secondly, a threshold was iden- tified at the end of the asphyxia phase (ca. 35 min) after which survival without a patent airway is unlikely. These aspects were later integrated into international guidelines on the management of avalanche victims 2,3 and resuscitation guidelines. 4 To understand whether these survival patterns pertained to other regions, the first comparative study of survival curves was published in 2011 using data from Switzerland and Canada. 5 For the first time it was shown that these four phases in the survival curve seem to be universal, but that their duration and contribu- tion to survival are modified by local factors. In this comparison, http://dx.doi.org/10.1016/j.resuscitation.2016.06.001 0300-9572/© 2016 Elsevier Ireland Ltd. All rights reserved.