Clinical outcomes of challenging out-of-hospital hypothermia management: A retrospective assessment of DOKEI protocol

Background: Accidental hypothermia (AH) is a major cause of death in mountainous areas globally, and the second highest of mountaineering deaths in Japan, accounting for 37 % in Hokkaido. Managing AH is a significant challenge, particularly when adverse weather complicates the application of recommended rewarming and rapid transfer. To address this, the Hokkaido Police Organization (DOKEI) AH protocol was applied in Hokkaido's remote areas from 2011 to 2022, integrating high-temperature active external rewarming (HT-AER) with on-site sustained treatment.

Methods: This study retrospectively analyzed the rescue reports and hospital records of hypothermia patients treated postprotocol, excluding patients with cold exposure, undetectable vital signs at rescue, and inadequate documentation. Protocol adherence and outcomes-hypothermia stage, cardiocirculatory collapse, survival, and neurological status-were assessed.

Results: Among the 60 protocol-treated patients (19-74 years, 85 % male), 14 had stage 2 hypothermia, and 3 had stage 3 hypothermia. HT-AER was applied in 96.7 % of the patients. A total of 98.3 % of patients improved before handover without cardiac arrest (CA) or extracorporeal life support (ECLS). Comparatively, ten preprotocol patients (18-60 years, 70 % male) had two CAs, one fatal and six with no improvement.

Conclusion: The DOKEI AH protocol demonstrates feasibility in managing stages 1-3 hypothermia, enhancing survival and neurological recovery, and can offer a vital option in challenging AH rescue scenarios.