OxyFile #395

Hypothermia and hyperbaric oxygen as treatment modalities for 
severe head injury.

Clifton GL

Department of Neurosurgery, University of Texas Houston Health 
Science Center, USA.

New Horiz, 3: 3, 1995 Aug, 474-8


Moderate systemic hypothermia has been shown to improve neurologic 
outcomes in both fluid-percussion and cortical contusion models of 
experimental brain injury. Based upon initial clinical work, it 
was concluded that at temperatures < 32 degrees C, patients with 
severe brain injury were at increased risk of ventricular 
arrhythmias, and that rapid rewarming immediately postinjury 
predisposed to intracranial pressure increases. Subsequent 
clinical studies of moderate hypothermia (32 degrees C) for 24- to 
48-hr duration with slow rewarming in human brain injury showed 
indications of neurologic improvement and a low incidence of 
hypothermia-related complications. Based upon the strengths of 
both laboratory and clinical data, a multicenter (nine centers), 
randomized, prospective trial testing moderate systemic 
hypothermia in patients with severe brain injury has been 
organized. This trial, funded by National Institutes of Health, 
National Institute of Neurological Disorders and Stroke, began on 
October 20, 1994. Five hundred patients are to be treated in an 
intent-to-treat protocol using standard management at normothermia 
versus standard management at hypothermia. The trial is designed 
to detect an absolute shift of 12% in the percentage of patients 
achieving satisfactory outcome (good recovery/moderate disability) 
at a power of 85% at 6 months postinjury. The efficacy of 
hyperbaric oxygen administered every 8 hrs for 1-hr duration for a 
2-wk period has also been tested in patients after severe brain 
injury. While the mortality rate was reduced in the treated group, 
the percentage of favorable outcomes was unchanged. Further 
studies are in progress.