Hyperbaric oxygen, perfluorochemical and artificial hypotension as an adjunct to acute reperfusion of middle cerecral arterial occlusion in cats

The effect of hyperbaric oxygen (HBO), perfluorochemical (PFC) and hypotensive reperfusion on postischemic cerebral edema was studied. The middle cerebral artery in cats was transorbitally occluded for 3 hrs and reperfused for 3 hrs. The cats whose CBF decreased to lower than 10ml/100g/min by the occlusion were used. The HBO (2atm, pure oxygen) was started one hour after the occlusion and continued for one hour. The mean arterial blood pressure was lowered artificially about 50mmHg from the previous value using adenosine triphosphate and dipyridamole just before and during the reperfusion. The value of CBF 3 hours after reperfusion was 8.2±11.0ml in the control group(n＝10), 18.1±12.2ml in the hypotension group(n＝6), 25.4±14.2ml in the PFC group(PFC with hypotension, n＝5), and 27.5±9.0ml in the HBO group(HBO with hypotension, n＝6). The ICP increased to 90.0±22.6mmHg in the control group and in the hypotension group to 37.7±10.1mmHg, in the PFC group to 43.2±17.1mmHg and in the HBO group to 29.8±20.9mmHg. The water content of the affected hemisphere was 79.7±0.5% in the control group, 79.1±0.5% in the hypotension group and 78.3±0.5% in the HBO group. These results suggest that the hypotensive reperfusion decreases vascular bed and reduces the strain on the vasoparalytic vascular wall thus improving the vasogenic edema. The PFC and the HBO help the metabolism of the vascular wall to improve during ischemia and maintain the strength of the vessel wall against intravascular pressure and reduce the edema. In conclusion, HBO, Pfc, and hypotensive reperfusion are useful as adjunts to actue cerebral revascularization.