Accidental hypothermia as an independent risk factor of poor neurological outcome in older multiply injured patients with severe traumatic brain injury: a matched pair analysis.

Patients with multiple injuries are particularly susceptible to accidental hypothermia which is correlated with an increased risk of post-traumatic complications and mortality; however, its impact on neurological outcome in cases where there is concomitant traumatic brain injury is underexplored. We analyzed severely injured patients (ISS ≥ 16) including a moderate-to-severe traumatic brain injury (AIS We analyzed 278 patients (M age = 43 years, SD 19; M ISS = 32.8, SD 10.7). Mortality was 17% (n = 14). 102 patients (37%) were hypothermic on admission. Hypothermic patients were more severely injured (ISS 35.6 ± 11.1 vs. 31.2 ± 10.1, p = 0.001; APACHE II 18.1 ± 7.4 vs. 16.2 ± 7.3, p = 0.045) and had a higher transfusion requirement. Mortality rate in hypothermic patients was increased (23.5 vs. 13.1%, p = 0.03); however, hypothermia was not an independent predictor of mortality. Median GOS at discharge was 3 (IQR 3); in 47% of patients the outcome was favorable (GOS 4 or 5) and 36% it was poor (GOS 2 or 3). There were no differences in post-traumatic complications. Analysis of 73 matched pairs of hypothermic and normothermic patients could not prove hypothermia as an independent predictor of poor neurological outcome (OR 1.7, 95% CI 0.8-3.6, p = 0.1) in the total population. However, older patients (> 41 years) had a 4.2-times higher risk (95% CI 1.4-12.7; p = 0.01) of poor neurological outcome, if they were hypothermic on admission. Accidental hypothermia seems to have a negative impact on neurological recovery in older patients with multiple injuries including traumatic brain injury which outweighs potential benefits.