Hypothermia

Objectives This study aimed to describe the cause of death and characteristics at the prehospital setting associated with care and rescue processes of non-survivors rescued in the mountain of Japan.

Design Retrospective analysis.

Setting Prehospital setting of mountain searches and rescues in Japan. A total of 10 prefectural police headquarters with >10 cases of mountain death from 2011 to 2015.

Participants Data were generated from the existing records. Of the total 6159 rescued subjects, 548 mountain deaths were caused by recreational activities.

Results Among the 548 mountain deaths, 83% were men, and major causes of death were trauma (49.1%), hypothermia (14.8%), cardiac death (13.1%) and avalanche-related death (6.6%). The alive rate at rescue team arrival in all non-survivors was 3.5%, with 1, 4 and 14 cases of cardiac, hypothermia and trauma, respectively. Cardiac deaths occurred in 93.1% (67/72) of men and individuals aged >41 years, and 88.7% (63/71) were found on mountain trails. In hypothermia, callouts were made between 17:00 and 6:00 at 49% (40/81) and by persons not on-site in 59.7% (46/77). People with >6 hours in trauma or >1 hour in cardiac death already died on rescue team arrival, but some with hypothermia after 6 hours were alive.

Conclusion This study is one of the first large-scale retrospective analyses of prehospital non-survivors in mountain emergencies. The alive rate at rescue arrival in all mountain deaths was only 3.5%. These data showed that the circumstances related to onset and the process until the rescue team arrives have different characteristics, depending on the cause of death. Survival may be enhanced by targeting better use of the time before rescue team arrival and by providing further education, particularly mountain rescue-related medical problems to rescuers including bystanders.

The growing popularity of activities such as hiking, climbing, skiing and snowboarding has ensured that the number of visitors to mountain environments continues to increase. Since such areas place enormous physical demands on individuals, it is inevitable that deaths will occur. Differences in the activities, conditions and methods of calculation make meaningful mortality rates difficult to obtain. However, it is clear that the mortality rate for some mountain activities is comparable to hang gliding, parachuting, boxing and other pastimes that are traditionally viewed as dangerous. Deaths in the mountains are most commonly due to trauma, high altitude illness, cold injury, avalanche burial and sudden cardiac death. This review describes the mortality rates of those who undertake recreational activities in the mountains and examines the aetiology that lies behind them.