[Cerebral edema following experimental subarachnoid hemorrhage (author's transl)]

Despite the fact that cerebral edema appears to be a common complication of subarachnoid hemorrhage (SAH) due to a ruptured cerebral aneurysm, measurements of brain tissue water content have not been carried out in this entity. For this reason, the development of cerebral edema has been analized in a newly developed experimental SAH model. SAH was induced in cats under controlled ventilation by withdrawing needles previously pierced into one or both infraclinoid internal carotid arteries through a unilateral transorbital approach. Intracranial pressure (ICP), blood pressure, cortical EEG and somatosensory evoked potentials (SEP) to sciatic nerve stimulation were monitored for 3 to 24 hours. Using labelled microspheres of 15 mu diameter, four serial determinations of regional cerebral blood flow (rCBF) were performed in one group of five animals before and immediately after SAH as well as 10 to 20 min, and 3 to 6 h post SAH. RCBF were obtained in 60 areas of the brain from tissue samples weighing about 150 mg. Brain tissue water content was determined by the vacuum freeze-drying weighing procedure in the same brain samples. In another group of five, brain tissue specific gravity (SG) was measured by microgravimetry in samples of brain tissue weighing 30 to 50 mg. Regional differences in SG as well as in water content were calculated from 21 untreated control animals.+2