Cerebral edema following experimental subarachnoid hemorrhage.

Abstract

The development of cerebral edema after experimental subarachnoid hemorrhage (SAH) was studied in cats by determining regional brain tissue water content with the microgravimetric technique as well as the drying-weighing method. SAH was induced by withdrawing needles previously pierced into one or both infraclinoid internal carotid arteries through a unilateral transorbital approach. Serial determinations of regional cerebral blood flow (rCBF) by labelled microspheres, and monitorings of vital signs such as intracranial pressure (ICP), blood pressure and EEG were carried out up to 24 h after SAH. Animals could be classified into three grades according to the severity of SAH. In grade I, the increase of ICP was transient and minor. In grade II, ICP increased up to 200 mm Hg with a marked reduction of rCBF below 20% of control in cerebral hemispheres. Following subsequent reduction of ICP, rCBF increased over control, indicating reactive hyperemia. Thereafter, a great reduction of rCBF was again observed. I...