The impact of avalanche rescue devices on survival.

BACKGROUND Within Europe and North America, the median annual mortality from snow avalanches between 1994 and 2003 was 141. There are two commonly used rescue devices: the avalanche transceiver, which is intended to speed up locating a completely buried person, and the avalanche airbag, which aims to prevent the person from being completely buried. OBJECTIVE This retrospective study aimed to evaluate whether these avalanche rescue devices had an effect on mortality. METHODS The study population was 1504 persons who were involved in 752 avalanches either in Switzerland from 1990 to 2000 and from 2002 to 2003 (1296 persons, 86.2%) or in Austria from 1998 to 2004 (208 persons, 13.8%). RESULTS Persons equipped with an avalanche airbag had a lower chance of dying (2.9% versus 18.9%; P=0.026, OR 0.09, n=1504). In persons who were completely buried, without visible or audible signs at the surface and who did not rescue themselves (n=317), we found a lower median duration of burial (25min versus 125min; P<0.001) and mortality (55.2% versus 70.6%; P<0.001, OR 0.26) in those using an avalanche transceiver than in those not using the device. CONCLUSIONS Our data showed that both the avalanche airbag and the avalanche transceiver reduce mortality. However, to improve the evaluation of rescue devices in the future, the data collection procedures should be reviewed and prospective trials should be considered, as the reliability of retrospective studies is limited.