Effects of the HEET Garment in the Prevention of Hypothermia in a Porcine Model

BackgroundHypothermia is a common battlefield trauma occurrence. This study compared the effectiveness of the hypothermia, environmental, exposure, and trauma (HEET) garment (Trident Industries, Beaufort, SC) with and without thermal inserts with a control group of two wool blankets in the prevention of hypothermia in a treated hypovolemic porcine model.Materials and methodsFive female swine (Sus scrofa-Yorkshire cross) were assigned to each of three groups: HEET with thermal inserts (n=5); HEET without thermal inserts (n=5); or control (n=5). After the animals were anesthetized and stabilized for 30min, the swine were hemorrhaged to a mean arterial pressure (MAP) of 30mm Hg, simulating a battlefield injury. Hetastarch 6% (500mL) was rapidly administered, simulating initial field resuscitation. One hour later, the animals' shed blood was reinfused, simulating transfusion at a field medical facility. The investigators moved the animal into a cooler set at 10°C±0.5°C. A pulmonary artery catheter was used to monitor core body temperature over a 6-h period.ResultsA repeated measures ANOVA and Tukey's post hoc test were used to analyze the data. There was a significant difference between the groups. At the end of 6h, the mean core temperature for the HEET with inserts group was 32.69°C±1.5; the HEET without inserts, 31.02°C±1.8; and control, 34.78°C±1.2 (P<0.05). While all groups became hypothermic, the wool blanket group was most effective in maintaining body temperature closer to normothermia.ConclusionThe HEET garments with and without heaters are ineffective in preventing hypothermia.