Studies of Cerebral Hemodynamics in Subarachnoid Hemorrhage

Abstract

Cerebral hemodynamics and metabolism in 32 cases of subarachnoid hemorrhage were investigated by the nitrous oxide method. Cerebral circulation was highly disturbed in the acute state of the disease, while it remained within the normal range in the remission stage. In patients with angiospasm visualized on the cerebral angiogram, cerebral circulatory disturbances were more severe than those without angiospastic patterns. Between the pressure of cerebrospinal fluid at lumbar puncture and cerebral blood flow, there was a negative correlation, whereas a roughly positive correlation was found between cerebral vascular resistance and pressure. In cases in which surgical clipping of aneurysm was done, remarkable improvement of the cerebral circulatory disturbances was generally noticed immediately after the operation. Cerebral vascular responses to 5% CO2 inhalation and hyperventilation were examined in 9 cases. In the acute stage, poor responsiveness to the vasodilatative stimulus was observed, while patients in the remission state showed a normal response. Furthermore, cerebral vasoconstriction by hyperventilation is more remarkable in the acute stage than in the remission state.