Continuous measurements of cerebral tissue oxygen pressure during hyperbaric oxygenation—HBO effects on brain edema and necrosis after severe brain trauma in rabbits

Abstract

Introduction: Severe brain injury is one of the most frequent causes of severe disability in the young. In acute management of brain trauma, new approaches based on experimental animal investigations should be sought. Methods: Twenty male, juvenile Chinchilla-Bastard rabbits received standardized cold-injury-induced-brain-trauma (CIBT). A metal probe (temperature −196 °C) was applied epidurally over 10 s. The hyperbaric oxygenation (HBO) group ( n=10) underwent 90-min HBO sessions with 100% oxygen at 2.5 atmospheres absolute (1 h, 24±2 h, 48±2 h after CIBT). Cerebral tissue pO 2-measurements were performed 60 min after CIBT, during the three HBO sessions and on day 4. The control group ( n=10) underwent no treatment. Animals were sacrificed on day 4, and brains were analyzed histologically. Results: In the HBO group, pO 2 measurements showed a significant increase in pO 2 between day 1 and day 4, whereas no significant changes were observed in the control group. During the first HBO session, mean pO 2 was 169 mm Hg, during the second 305 mm Hg and during the third 420 mm Hg. The mean area of necrosis was 16.2 mm 2 in the HBO group, in the control group 19.9 mm 2. The areas of brain edema were significantly smaller in the HBO group. Mortality in the HBO group was 0%, in the control group 20%. Conclusion: HBO appears to be beneficial as an adjunct treatment of severe head trauma. To find optimal treatment protocols, further clinical studies must be developed.