Study on therapeutic mechanism and clinical effect of mild hypothermia in patients with severe head injury

BACKGROUND The therapeutic mechanism and clinical effect of mild hypothermia in patients with severe head injury were studied. METHODS All 396 patients with severe head injury [Glasgow Coma Scale score (GCS) equal to or less than 8 on admission] were randomly divided into the hypothermic group (198 cases) and the control group (198 cases). Hypothermia was induced within 24 hours of injury. Rewarming began 1 to 7 days (average 62.4 +/- 27.6 h) after the rectal temperature (RT) reached 32.0 to 35.0degreesC. Meanwhile, the vital signs, intracranial pressure (ICP), blood gas values, blood electrolytes, brain tissue oxygen pressure (PbtO2), brain tissue temperature (BT), cerebral blood flow (CBF), and jugular venous oxygen saturation (SjvO2) were measured. The rectal temperature of control patients was induced to 36.5 to 37.0degreesC. According to GOS, the prognosis of the patients was evaluated. RESULTS In comparison with control group, during mild hypothermia the high level of ICP, hyperglycemia and blood lactic acid significantly decreased (p < 0.05) and cerebral flow improved dominantly. The vital signs, blood gas values, and blood electrolytes did not change significantly. Decreased mortality and good recovery were also found in hypothermia group. CONCLUSIONS Mild hypothermia is safe and effective for preventing brain damage on patients with severe head injury, as well as reducing mortality and improving the prognosis. It is important to monitor PbtO2, BT, CBF, and SjvO2 in hypothermic therapy. (C) 2003 Elsevier Inc. All rights reserved.