Studies on Hypertension

HIGH spinal anesthesia was employed in previous studies 1 to lower the blood pressure of patients with essential hypertension. From these studies certain information and conclusions have been drawn regarding the probability that the drop in blood pressure is due to interruption of vasomotor function. The work of Smith and his associates 2 and Rovenstine and his associates 3 suggested that the fall in blood pressure due to spinal anesthesia is due to decreased cardiac output resulting from decreased venous pressure and diminished venous return to the heart. In view of the fact that both of these studies were done on subjects with normal blood pressure, it appears necessary that these observations be applied to patients with essential hypertension. It is conceivable that the role played by the vasomotor apparatus in maintaining normal blood pressure may be different from the role of this mechanism in maintaining elevations of arterial