Feasibility and safety of moderate hypothermia after massive hemispheric infarction

Background and Purpose-Moderate hypothermia decreases ischemic damage in ex perimental stroke models. This multicenter study was performed to evaluate (1) the safety and feasibility of moderate hypothermia and (2) its potentia l to reduce intracranial hypertension in acute stroke patients. Methods-Fifty prospective patients with cerebral infarction involving at le ast the complete middle cerebral artery territory treated with moderate hyp othermia were evaluated. Hypothermia was induced with the use of cooling bl ankets as well as alcohol and ice bags within 22 +/- 9 hours after stroke o nset and maintained for 24 to 72 hours; subsequently, patients passively re warmed over a mean duration of 17 hours. Outcome was assessed at 4 weeks an d at 3 months. Results-Time required for cooling to <33<degrees>C varied from 3.5 to 11 ho urs. The most frequent complications of hypothermic therapy were thrombocyt openia (70%), bradycardia (62%), and pneumonia (48%). Four patients (8%) di ed during hypothermia as a result of severe coagulopathy, cardiac failure, or uncontrollable intracranial hypertension. An additional 15 patients (30% ) died during or after rewarming because of rebound increase in intracrania l pressure (ICP) and fatal herniation. A shorter (<16 hours) rewarming peri od was associated with a more pronounced rise of ICP. Elevated ICP values w ere significantly reduced under hypothermia. Neurological outcome according to the National Institutes of Health Stroke Scale score 4 weeks after stro ke was 29, and Rankin Scale score 3 months after stroke was 2.9. Conclusions-Moderate hypothermia is feasible in patients with acute stroke, although it is associated with several side effects. Most deaths occur dur ing rewarming as a result of excessive ICP rise. Our preliminary observatio n that a longer duration of the rewarming period limits the ICP increase re mains to be confirmed in future studies.