The effect of bilateral stellate ganglion block on the cerebral circulation in normotensive and hypertensive

Stellate ganglion block has been used in the treatment of cerebral derangements thought to be associated with angiospasm, for the purpose of relieving spasm and presumably increasing the cerebral blood flow (1-4). In view of this clini-cal development the question of the role of the sympathetic nervous system in the control of the cerebral circulation becomes more than an aca-demic one. The only experimental work in man has been that of Risteen and Volpitto (3) who observed through burr holes an increase in the diameter of the pial vessels following stellate block. A number of clinical observations, ascrib-ing dramatic results of stellate block to the re-lease of cerebral angiospasm, have appeared since Leriche and Fontaine (1) first reported their experience with two cases of cerebral embolism. With the development of the nitrous oxide method for measuring cerebral blood flow (5-7) a quan-titative technique has been made available for clinical study of this problem. Quantitative data can be obtained concerning the fundamental phys-iology of the cerebral circulation following block of that part of the sympathetic innervation of the cerebral vessels passing through the stellate and middle cervical ganglia. This information may permit evaluation of stellate block as a means o