Prognostic factors in avalanche resuscitation: a systematic review

Objective: Avalanche resuscitation will save lives if focussed on victims that have the potential to survive. The purpose of this systematic review was to examine 4 critical prognostic factors for burial victims in cardiac arrest.

Methods: Time of burial, airway patency, core temperature and serum potassium level were analyzed as PICO (Patient/population, Intervention, Comparator, Outcome) questions within the 2010 Consensus on Science process of the International Liaison Committee on Resuscitation. The electronic databases of Medline via PubMed, EMBASE via OVID and the Cochrane Database of Systematic Reviews were searched using combinations of the search terms "avalanche", "air pocket", "hypothermia" and "serum potassium".

Results: Of 1910 publications that were identified 30 were found relevant. The predictive value for survival of a short time of burial or a patent airway after 35 min of burial is supported by 10 retrospective case-control studies, 4 case series and 2 experimental studies, while no studies are neutral or opposed. A core temperature of less than 32 degrees C with a patent airway is supported by 2 retrospective case-control studies and 3 case series, while 10 studies are neutral. Serum potassium level is supported by 6 retrospective case-control studies and 3 case reports, while 3 retrospective case-control studies and 1 animal model are neutral.

Conclusion: After 35 min of burial, or where the core temperature is less than 32 degrees C, a patent airway is associated with survival to hospital discharge. A serum potassium of less than 7 mmol/L may be a valuable indicator for survival when other indicators are unclear. These findings should modify the current avalanche resuscitation scheme.