Circulatory responses to spinal and caudal anesthesia in hypertension: Relation to the effect of sympathectomy

The effects of caudal and spinal anesthesia on arterial pressure in hypertension are similar despite the fact that in the former, voluntary muscles are not paralyzed. During anesthesia marked decreases in pressure were observed in forty of the forty-three patients. Blood pressure was persistently decreased by lumbodorsal sympathectomy and ganglionectomy in twelve of these patients. The three patients whose arterial pressures were not decreased by anesthesia were similarly unaffected by operation. It is concluded that the blood pressure response to spinal and caudal anesthesia has no more than negative value in the selection of patients for sympathectomy. The discrepancy between the effects on arterial pressure of spinal or caudal anesthesia and sympathectomy may be due to the great difference in time during which the effects are observed or to a difference in the denervation which each of them causes.