Prolonged Cerebral Hyperemia after Periods of Increased Cerebrospinal Fluid Pressure in Dogs

Abstract

Abstract In 23 dogs the cerebral blood flow was measured with the intra‐arterial radioactive injection technique during and after the application of a high cerebrospinal fluid pressure by infusion of artificial cerebrospinal fluid into the subarachnoid space. Increased cerebral blood flow was observed in most cases when the cerebral perfusion pressure was restored after a period with cerebrospinal fluid pressure over 50 mm Hg. The hyperemia always occurred if during the period of high intracranial pressure the blood flow had been reduced below the control value: in a few cases it appeared also without a preceding flow reduction. In almost all cases there was a marked tendency to normalization of the blood flow after the initial period of hyperemia. No chemical factors in the artificial cerebrospinal fluid could be made responsible for the phenomenon described, which is attributed to a disturbance of cerebrovascular function, impairing the ordinary flow autoregulation.