Changes in Systemic Carbon Dioxide Levels During Simulated Avalanche Burial Using a One-way Valve Device: a Double Blinded, Randomized Cross-over Trial

Every year, around 100 people die in avalanches in the Alps. Many of these accidents occur during winter sports. In most cases, the victims suffocate under the snow after the avalanche has come to a standstill. A key survival factor here is the time it takes to be rescued. If a buried victim is rescued within 15 minutes, the probability of survival is over 90%. After 35 minutes, however, this drops drastically to just 30%.

A modern avalanche rescue system, such as the AvaLung-device, could extend the survival time. The system directs the exhaled air via a tube to the back of the buried person so that no toxic CO2 concentrations build up in the available breathing cavity. It is also intended to prevent the formation of an "ice mask", which can impair the release of oxygen from the snow. This study investigates whether the AvaLung system can extend the survival time in the event of burial.

The aim is to test the effects of such a breathing tube system. The oxygen and carbon dioxide levels of the test subjects are measured while they are buried in a simulated avalanche - once with and once without the AvaLung system. In addition, it is investigated how long it takes before the buried subjects have to stop the examination, for example due to shortness of breath or deteriorating respiratory gases in the blood.

Test setup:

The test subjects lie on their backs with their heads and chests buried under snow. During the test phase, various parameters are continuously monitored, such as the breathing rate and the CO2 concentration in the blood. A comparative study is carried out: once with a functioning rescue system, and once with a manipulated (non-functioning) system.

Expected benefit:

The results of this study should contribute to a better understanding of the effectiveness of avalanche rescue systems and thus increase the chances of survival of avalanche victims in the future. This is particularly important today, as the number of winter sports enthusiasts and the number of avalanches triggered by them is constantly increasing.