Mild Hypothermia and Supplemental Magnesium Sulfate Infusion in Severe Traumatic Brain Injury (TBI) Subjects

The investigators hypothesize that hypothermia (body cooling) and additional magnesium sulfate will improve the outcome of severe Traumatic Brain Injury (TBI) patients. This is a study to compare the outcomes of patients with severe traumatic brain injury who have been allocated to one of the following three groups: Group 1 - Conventional therapy following traumatic brain injury Group 2 - Subjects will have their core body temperature lowered to 34C Group 3 - Subjects will have their core body temperature lowered to 34C and will receive a supplemental intravenous infusion of magnesium sulfate.