Pre-hospital hypothermia is not associated with increased survival after traumatic brain injury

Background: Conclusions from in vivo and in vitro studies suggest hypothermia may be protective in traumatic brain injury (TBI). Few studies evaluated the effect of admission temperature on outcomes. The purpose of this study is to examine the relationship between admission hypothermia and mortality in patients with isolated, blunt, moderate to severe TBI.

Methods: The Los Angeles Trauma Database was queried for all patients ≥ 14 y of age with isolated, blunt, moderate to severe TBI (head abbreviated injury score (AIS) ≥ 3, all other <3), admitted between 2005 and 2009. The study population was then stratified into two groups by admission temperature: hypothermic (≤ 35°C) and normothermic (>35°C). Demographic characteristics and outcomes were compared between groups. Logistic regression analysis was used to determine the relationship between admission hypothermia and mortality.

Results: A total of 1834 patients were analyzed and then stratified into two groups: hypothermic (n = 44) and normothermic (n = 1790). There was a significant difference noted in overall mortality (25% versus 7%), with the hypothermic group being four times more likely to succumb to their injuries. After adjusting for confounding factors, admission hypothermia was independently associated with increased mortality (AOR 2.5; 95% CI 1.1-6.3; P = 0.04).

Conclusions: Although in-vivo and in-vitro studies demonstrate induced hypothermia may be protective in TBI, our study demonstrates that admission hypothermia was associated with increased mortality in isolated, blunt, moderate to severe TBI. Further prospective research is needed to elucidate the role of thermoregulation in patients sustaining TBI.