Emergency medical helicopter operations for avalanche accidents.

BACKGROUND: In the European Alps emergency medical helicopter services are regularly involved in avalanche rescue missions. How the helicopter emergency medical system best supports avalanche rescue missions is controversial. AIM OF THE STUDY: To study advantages and limitations of the early dispatch of emergency medical helicopters after avalanche accidents. METHODS: Data on rescue mission characteristics and patterns and severity of medical emergencies were obtained for 221 helicopter avalanche rescue missions performed in the Austrian province of Tyrol between October 2008 and June 2011. RESULTS: A buried avalanche victim had to be searched for in only 12 (5.5%) of the 221 rescue missions, whereas medical emergencies were encountered at the scene in 24 missions (11%). Survival rate for totally buried victims extricated after helicopter arrival was significantly lower than for victims extricated before helicopter arrival (19% versus 74%, p=0.0002). In 124 missions (56%) no victim was present at the scene when the helicopter arrived. Medical emergencies involved normothermic cardiac arrest (n=11), severe accidental hypothermia (n=6), critical trauma (n=7) and hypothermia combined with critical trauma (n=1). Survival rate at hospital discharge was 27% for arrested normothermic patients and 50% for trauma and hypothermia patients. CONCLUSIONS: Medical emergencies are encountered at avalanche scenes twice as often as there is need to search for totally buried victims, clearly supporting the immediate dispatch of medical crew members to the accident site. The high rate of emergency medical helicopter operations to avalanche incidents where no victim is injured or buried may be characteristic for densely populated mountainous regions and can be reduced by a restrictive dispatch policy after avalanche accidents without clear information about human involvement.

Correlation between avalanche emergencies and avalanche danger forecast in the alpine region of Tyrol.

OBJECTIVE: We investigated whether frequency of avalanche accidents corresponds with the danger assessment given in avalanche hazard tables and with topographic factors of the avalanche origin. METHODS: A retrospective review of official avalanche surveillance data and of medical reports from helicopter-based emergency medical systems was conducted. RESULTS: Most victims involved in avalanche accidents are ski tourers and off-piste skiers, about 90% are male, and age ranges from 10 to more than 70 years. Sixty-seven percent of accidents occurred when moderate and considerable danger was forecast. In 94.0% of accidents avalanches were triggered by victims themselves or by nearby recreationists; 32.6% of avalanche slides occurred on extremely steep slopes at gradients exceeding 40 degrees . Overall incidence of accidents before noon was 25.0%. Professional stand-by avalanche parties significantly contributed to rescuing avalanche victims, but the chance of survival is diminished when arrival was delayed. All patients who were able to free themselves from avalanche burial survived. Of those rescued by companions, 78.0% survived compared with only 10.0% of those rescued by organized rescue teams (P<0.001). CONCLUSION: Frequency of avalanche emergencies associated with outdoor leisure activities does not correspond with the danger forecast in avalanche hazard bulletins. There is need of a modified and regionally adjusted grading that makes allowance for experience and individual behavior of recreationists going in for backcountry leisure activities.