Controlled trials of therapeutic hypothermia used for at least 24 hours compared to normothermia in adults with a closed traumatic brain injury and a Glasgow Coma Scale (GCS) score of between 3 and 8 with outcomes measured by GCS were eligible for inclusion.
Exclusion criteria applied in the included studies were: clinical brain death; prolonged hypoxia or hypotension; gunshot wound; pregnancy; undetermined time of injury; inability to begin cooling within six hours; organ failure of another system; and normal findings on a computerised tomography scan. In the hypothermia groups, patients' temperatures were cooled to 32°C to 35°C over periods of time that ranged from 24 hours to five days. The most commonly used method to achieve hypothermia used cooling blankets. Mean time to hypothermia attainment ranged from three hours to 24 hours. Temperatures in normothermia control groups were maintained between 36.5°C and 38.5°C by use of cooling blankets. In one study, use of short-term mild hypothermia (two days) was compared to use of long-term hypothermia (five days). Outcomes measured were intracranial pressure, cerebral perfusion pressure, arterial blood pressure, continuous temperature and management appropriate for traumatic brain injury.
The author did not state how studies were selected for inclusion.