Significance of differences between brain temperature and core temperature (δ T) during mild hypothermia in patients with diffuse axonal injury.

The differences between brain and bladder temperature (delta T), and the relationship of delta T to cerebral perfusion pressure (CPP) and jugular venous oxygen saturation (SjO(2)) were studied during hypothermia in 11 patients with severe traumatic brain injury, of whom 5 underwent conservative treatment for diffuse axonal injury (DAI) (DAI group) and 6 who underwent decompressive craniectomy for hematoma (SDH group). All patients underwent hypothermia treatment. Brain temperature was monitored via an intraparenchymal catheter. Bladder temperature was used as the core temperature. SjO(2) was measured continuously. The outcome of all patients was evaluated at discharge using the Glasgow Outcome Scale. Delta T in the SDH group was significantly lower than that in the DAI group. No relationship was found between delta T and CPP during the investigation period. A significant correlation between delta T and SjO(2) was seen in the DAI group, but not in the SDH group. Decompressive craniectomy affects the brain temperature through external environmental factors. Measurement of brain temperature may be a reliable indicator of cerebral blood flow and brain metabolism in patients with DAI and closed cranium during hypothermia. Further experience is required to test this proposal.