Expeditionary Immersion Circulating Heating Device: A Promising Technique for Treating Frostbite Injuries and Warming Intravenous Fluids in a Forward Deployed Cold Weather Environment

Abstract

Cold weather injuries require prompt warm water immersion therapy, which proves to be a difficult task in the cold austere environment. Current guidelines recommend 104°F water immersion, but producing and maintaining large volumes of warm water is challenging in sub-freezing temperatures. We describe a novel process of utilizing a sous vide immersion circulator to maintain warm fluids for immersion therapy and efficient fluid rewarming in a cold forward-deployed setting for the treatment of cold weather injuries in an effort to bridge the gap between current medical guidelines and practices. Large water cans were warmed to 104°F with the immersion circulator. A thermometer was inserted into a 1-inch steak, frozen to 30°F, and placed in a basin with only the warmed water while the internal temperature was monitored until physiologic temperature was achieved. The time to this endpoint was recorded. A 1-L bag of normal saline and a 450-mL bag of whole blood were also separately warmed by the same technique. The temperature of the normal saline was monitored at 0-, 5-, 7-, 8-, 9-, and 10-minute intervals. The process was similarly repeated, measuring the whole blood temperature at 0-, 5-, 7-, and 10-minute intervals. Ambient internal tent temperatures averaged 54°F; outdoor temperatures were consistently sub-freezing. The 5-gallon cans of water at ambient temperature heated to 104°F in 15minutes. The water temperature remained constant for 3weeks with the circulator running. The frozen steak started at 30°F and reached 98°F in 52minutes and 45seconds. The bag of normal saline and whole blood, refrigerated to 39°F, achieved temperatures of 102°F and 94°F respectively after 10minutes. A heating immersion circulator device is a lightweight, flameless, and inexpensive way to consistently heat large volumes of water for treatment of cold weather injuries, hypothermia, and whole blood rewarming in a cold austere environment.