Early effects of experimental arterial subarachnoid haemorrhage on the cerebral circulation. Part I: Experimental subarachnoid haemorrhage in cat and its pathophysiological effects. Methods of regional cerebral blood flow measurement and evaluation of microcirculation.

Studies of pathophysiological changes, regional cerebral blood flow (rCBF) and cerebral microcirculation were performed in cats subjected to arterial subarachnoid haemorrhage (SAH). An original method for SAH imitating aneurysm rupture was developed. The bleeding was induced by puncturing of the internal carotid artery approached tranpresphenoidally and followed by immediate closure of the skull opening. It was found, that arterial subarachnoid bleeding elevates intracranial pressure and results in a transitory fall in cerebral perfusion pressure which is not prevented by elevation of arterial blood pressure (Cushing reflex). A depression in brain electrical activity and respiration rate were present in the course of subarachnoid haemorrhage.