Effect of Air Exposure Time Under Room-Temperature Conditions on the Performance of Chemical Heat Blankets Intended for Use in Prehospital Accidental Hypothermia

IntroductionAccidental hypothermia increases mortality in patients with traumatic injury, making hypothermia management essential in prehospital trauma care. Chemical heat blankets are commonly used for this purpose. These blankets require time to get warm, with agitation often used to accelerate the exothermic reaction. Many search and rescue teams use chemical heat blankets, but optimal activation of the blankets remains uncertain. This study investigated how varying oxygen exposure durations affect the thermal performance of these blankets to guide their optimal use in search and rescue scenarios.MethodsIn room-temperature conditions, a full-body manikin was wrapped in a standardized hypothermia model, including a chemical heat blanket, and evaluated under 3 conditions: 1) no shaking, 2) shaking for 2 min, and 3) shaking for 15 min before wrapping. Thermometers were placed inside the heating panel pockets and secured in place with tape to ensure consistent measurements. Temperature data were collected over 6 h, and each scenario was performed 4 times.ResultsBlankets shaken for 2 min achieved higher initial temperatures than those not shaken, with a significant difference sustained for 88 min. Shaking for 15 min resulted in higher initial temperatures than 2-min shaking, with no long-term difference. All scenarios converged to the same temperature (36°C) after 6 h.ConclusionShaking the blanket for 2 min significantly improved early heating performance, whereas longer shaking offered minimal benefit. These findings suggest that short preparation time may be adequate in optimizing thermal delivery and reducing the time to treatment for patients with prehospital accidental hypothermia.