Brain Temperature and Outcome After Severe Traumatic Brain Injury

Abstract

In humans, raised body temperature is linked to poor outcome after brain injury. Because deviations between brain and body temperature have been reported after severe traumatic brain injury (TBI), the aim of this study was to explore the relationship between initial and mean brain temperature and survival at 3 months. Intraparenchymal temperature was measured 3 - 4 cm within white matter. Logistic regression was used to explore linear and quadratic relationships between initial and average brain temperature and survival at 3 months. In 36 patients, initial brain temperatures ranged from 33.5 to 39.2 degrees C (median 37.4 degrees C). There was no evidence of an association between initial brain temperature and risk of death, either linear (odds ratio [OR] 95% confidence interval [CI] = 1.3 [0.68 to 2.5], p = 0.42) or quadratic ( p = 0.26). Assuming a linear relationship, patients with higher mean brain temperatures were less likely to die: OR (95% CI) for death per 1 degrees C was 0.31 (0.09 to 1.1), p = 0.06. However, by fitting the quadratic relationship, there was a suggestion that both high and low temperatures were associated with increased risk of death: p = 0.06. Initial brain temperature measured shortly after admission did not predict outcome. There is a suggestion that patients with "middle range" temperatures were less likely to die.