THE EFFECTS OF AN ACUTE REDUCTION IN BLOOD PRESSURE BY MEANS OF DIFFERENTIAL SPINAL SYMPATHETIC BLOCK ON THE CEREBRAL CIRCULATION OF HYPERTENSIVE PATIENTS 1

Abstract

Studies are reported of arterial and internal jugular blood gases, cerebral blood flow, oxygen consumption, and vascular resistance obtained by the nitrous oxide technic in patients with essential hypertension before and after a reduction in blood pressure achieved by differential spinal sympathetic block. The high cerebrovascular resistance of essential hypertension is capable of partial relaxation in response to a fall in blood pressure. This relaxation is not complete with the result that with severe reduction in blood pressure to normo-tensive levels there is a significant reduction in cerebral blood flow and evidence of cerebral anoxia.