HYPERBARIC-OXYGEN AFTER GLOBAL CEREBRAL-ISCHEMIA IN RABBITS REDUCES BRAIN VASCULAR-PERMEABILITY AND BLOOD-FLOW

Background and Purpose Hyperbaric oxygen (HBO) has been advocated as a therapy to improve neurological recovery after ischemia, since HBO may improve tissue oxygen delivery. We examined the effect of HBO treatment after global cerebral ischemia on early brain injury. Methods Rabbits were subjected to 10 minutes of global cerebral ischemia by cerebrospinal fluid compression. After 30 minutes of reperfusion, rabbits either were subjected to HBO for 125 minutes and then breathed 100% O-2 at ambient pressure for 90 minutes or breathed 100% O-2 for 215 minutes. At the end of reperfusion and 90 minutes after exposure, brain vascular permeability and cerebral blood flow were measured. Somatosensory evoked potentials were monitored throughout the experiment. Results HBO treatment reduced (P<.05) brain vascular permeability by 16% in gray matter and by 20% in white matter. Cerebral blood flow was lower (P<.05) in the HBO group (40.9+/-1.9 mL/min per 100 g, mean SEM) compared with controls (50.8+/-2.0 mL/min per 100 g). Somatosensory evoked potential recovery was similar in the two groups (P>.05). Conclusions HBO administered after global cerebral ischemia promoted blood-brain barrier integrity. HBO treatment also reduced cerebral blood flow; this effect was not associated with a reduction in evoked potential recovery. Since neurological outcome after global cerebral ischemia is generally poor and treatment options are limited, HBO should be further investigated as a potential therapy.