SELECTION OF SEVERELY HEAD-INJURED PATIENTS FOR MILD HYPOTHERMIA THERAPY

Object. The authors have analyzed the efficacy of inducing mild hypoth ermia (34 degrees C) in 62 severely head injured patients to control f ulminant intracranial hypertension. Methods. All 62 patients fulfilled the following criteria: 1) persistent intracranial pressure (ICP) gre ater than 20 mm Hg despite fluid restriction, hyperventilation, and hi gh-dose barbiturate therapy; 2) an ICP lower than the mean arterial pr essure; and 3) a Glasgow Coma Scale (GCS) score of 8 or less on admiss ion. The patients were divided into three groups based on computerized tomography findings: extracerebral hematoma (34 patients with subdura l and/or epidural hematoma), focal cerebral lesion (20 patients with l ocalized brain contusion and/or intracerebral hematoma), and diffuse s welling (eight patients with no focal mass lesion). Mild hypothermia p revented ICP elevation in 35 (56.5%) of the 62 patients whose ICP was greater than 20 mm Hg despite conventional therapies. Among those 35 p atients whose ICP was controlled by mild hypothermia, 12 (34.3%) achie ved functional recovery (good outcome or moderate disability). However , functional recovery was observed in only five (10.9%) of the 46 pati ents whose ICP was greater than 40 mm Hg after conventional therapies. Of 40 patients with an admission GCS score of 5 to 8, there were 11 ( 27.5%) who achieved functional recovery. On the contrary, mild hypothe rmia was not effective in 22 patients with an admission GCS score of 3 or 4. In the patients with focal cerebral lesions. ICP was controlled by mild hypothermia in 17 patients (85%) and patient outcome was inti mately related to the extent of the damage. Among 18 patients with ext racerebral hematoma who had a midline shift of 9 to 12 mm, raised ICP could be successfully controlled by mild hypothermia in 16 patients (8 8.9%) and three (16.7%) achieved functional recovery. However, ICP cou ld not be controlled in patients with extracerebral hematoma who had a midline shift of 13 mm or more. In patients with diffuse swelling, IC P elevation could not be prevented at all by mild hypothermia. Conclus ions. The authors conclude that mild hypothermia is effective for prev enting ICP elevation in patients without diffuse brain swelling in who m ICP remains higher than 20 mm Hg but less than 40 mm Hg after conven tional therapies.