Human Responses to 5 Heated Hypothermia Wrap Systems in a Cold Environment

Area of Science:

• Environmental Physiology
• Thermoregulation Research
• Wilderness Medicine Equipment

Background:

• Hypothermia poses a significant risk in cold environments.
• Effective thermal management systems are crucial for preventing hypothermia.
• Evaluating the efficacy of heated hypothermia wraps is essential for outdoor safety.

Purpose of the Study:

• To compare the effectiveness of five different heated hypothermia wrap systems.
• To assess both physiological and subjective responses to these systems under extreme cold conditions.
• To identify the most effective heated wrap systems for preventing hypothermia.

Main Methods:

• Five heated hypothermia wrap systems were tested on five normothermic subjects.
• Subjects were exposed to -22°C for 60 minutes with vapor barriers and chemical heat sources.
• Core and skin temperatures, metabolic heat production, heat loss, and net heat gain were measured, alongside subjective responses.

Main Results:

• The Doctor Down Rescue Wrap and user-assembled systems showed higher skin temperatures and net heat gain, with less heat loss.
• These two systems also exhibited lower metabolic heat production compared to others.
• The hypothermia prevention and management kit (HPMK) resulted in the lowest skin temperature and highest shivering, with poor subjective ratings.

Conclusions:

• User-assembled and Doctor Down systems were the most effective in maintaining body heat.
• The hypothermia prevention and management kit (HPMK) was the least effective, leading to the coldest subjective experience.
• All systems may be viable for wilderness responders, with selection dependent on cost, size, and weight.