The Effect of Environmental Hypothermia on Survival in Isolated Blunt Traumatic Brain Injury

Background: Environmental hypothermia increases mortality in patients with major trauma; however, the impact of exposure hypothermia on outcomes in isolated traumatic brain injury (TBI) is underexplored in literature. The aim of this study is to determine the relationship between environmental hypothermia and survival in patients with isolated blunt TBI. Methods: We analyzed data from the Trauma Quality Improvement Program database. We included patients who were aged ≥15 years, had an abbreviated injury scale ≥1 for the head/neck body region, an arrival Glasgow Coma Scale of <14, an abbreviated injury scale of 0 for all other body regions, and a blunt mechanism. We defined hypothermia as <35°C. Results: From 2020 to 2022, there were 16,697 patient encounters that met inclusion for this analysis. There were 670 (4%) patient encounters that met our definition of hypothermia. Hypothermic patients had lower unadjusted survival at 24 hours (79% vs. 92%) and throughout their hospital stay (47% vs. 77%, all P < 0.001). In our multivariable logistic regression model, after adjusting for age, sex, arrival Glasgow Coma Scale, arrival shock index, mechanism of injury, and imaging findings, hypothermia was associated with lower survival at 24 hours (odds ratio: 0.59; 0.48–0.74) and lower total in-hospital survival (odds ratio: 0.44; 0.36–0.53). Conclusions: Environmental hypothermia is associated with increased mortality at 24 hours and at hospital discharge in patients with isolated blunt TBI. Further investigation is needed to identify optimal treatment strategies for TBI patients with hypothermia and to determine whether hypothermia prevention decreases mortality.