[The effect of artificial hypotension on postischemic cerebral edema in the reperfusion of middle cerebral arterial occlusion in cats--experimental study].

The effect of hypotension on postischemic cerebral edema was studied by the occlusion-reperfusion model of the middle cerebral artery (MCA) of a cat. The middle cerebral artery was transorbitally occluded for 3 hrs and reperfused for 3 hrs. We chose cats whose CBF decreased lower than 10 ml/100 g/min by the MCA occlusion. We studied 10 cats as a control group and 6 cats as the hypotension group. The mean arterial blood pressure was lowered artificially about 50 mmHg from the previous value using ATP and dipyridamole just before and during the reperfusion. The CBF was measured by the hydrogen clearance method and extradural pressure was recorded. The water content of cerebral hemisphere was measured by the drying-weighing method after sacrifice. In the control group the preocclusive value of CBF was 65.9 +/- 20.6 ml/100g/min and the value just after reperfusion was 35.0 +/- 21.5 ml. The value 3 hours after reperfusion was 8.2 +/- 11.0 ml. In the hypotension group, these values were 53.9 +/- 14.0 ml, 40.6 +/- 19.6 ml and 18.1 +/- 12.2 ml respectively. The ICP increased from 9.1 +/- 8.6 to 90.0 +/- 22.6 mmHg in the control group and in the hypotension group from 4.5 +/- 6.5 to 37.7 +/- 10.1 mmHg. The water content of the affected hemisphere was 79.7 +/- 0.5% in the control group and 79.1 +/- 0.5% in the hypotension group. The hypotension didn't change the CBF just after reperfusion and also maintained it more than the control until 3 hrs after the reperfusion.(ABSTRACT TRUNCATED AT 250 WORDS)