Comparing Warming Methods in the Trauma Bay: A Multi-center Cohort Study.

Background Despite the clear link between hypothermia and poor outcomes, few studies have evaluated warming methods in the trauma bay. This study aimed to compare the effectiveness of three warming methods for full trauma activations arriving at the emergency department. Methods A multi-site, retrospective cohort study was conducted at two Level I and one Level II trauma centers in North Texas, United States, from August 1, 2023, to July 31, 2024. Body temperature data were collected for three warming methods: blankets, forced air underbody warming mattress, or forced air warming mattress plus thermo-reflective head cap. The ability of warming devices to treat/prevent cold stress was tested with Cox hazard models that controlled for known confounders. As study sites did not share standardized warming device workflows or temperature measurement protocols, nesting of patients within hospitals and potential confounding effects of the study sites were addressed with cluster robust standard errors. Results Patients were treated with blankets (n = 99), mattresses (n = 92), or mattresses + caps (n = 19). Cap use was rare due to prevalent contraindications. For patients arriving normothermic (n = 98; arrival temperature 36.8 oC ± 0.3), Cox modelling indicated the mattress was not reliably better than blankets at preventing new cold stress (<36.5 oC; p = 0.343). For patients arriving with cold stress (n = 112; arrival temperature 35.7 oC ± 0.9), Cox modelling revealed normothermia was 4.7 times as likely to be achieved with the mattress than with blankets after controlling for confounders (p <0.001). Conclusion Application of the forced air underbody warming mattress was feasible and practical in the trauma bay and more effective than blankets in correcting cold stress. The thermally reflective head cap was impractical due to the prevalence of head injuries and the routine need for computerized tomography scans of the head.