Objective:To further study the clime value of mild hypothermia for severe head injury through monitoring and analyzing the changes of brain tissue PO 2 (P br O 2) in patients with severe head injury.Methods:42 patients with severe head injury were selected for this study.Mild hypothermia group received cooling 32～34℃

for 3～5 days within 12 hours after head injury.Control group received ordinary treatment.P br O 2 in all patients were continuously monitored.Results:There was no difference in P br O 2 between severe head injury patients in both groups (GCS 6～8) before cooling

4 hours after cooling or after rewarming( P >0.05 );P br O 2 was lower in cooling group than that in control group at 24 hours/48 hours/72 hours after cooling ( P <0.05 ).There was no difference between patients with GCS 3～5 in both groups at different periods ( P >0.05).The mortality rate of patients with severe head injury (GCS 6～8) in mild hypothermia group is obviously lower than that in control group ( P <0.05).There was no difference in mortality rate between patients with GCS 3～5 in two groups.Conclusion:The mortality rate of severe head injury (GCS 6～8) patients decreased through mild hypothermia therapy

but P br O 2 of the severe head injury (GCS 6～8) patients treated with mild hypothermia decreased at the same time.To patients with GCS 3～5

mild hypothermia therapy is ineffective.