[Reevaluation of spinal anesthesia in elderly people--an evaluation of circulatory changes]

Appropriate methods of anesthesia for the elderly people are being discussed as the ratio of elderly people in our society increases. During spinal anesthesia, hypotension was frequently observed in patients with hypertension, arteriosclerosis, coronary deficiency, and so on. It is also difficult to pass the needle between degenerated vertebrae. However, general inhaled anesthesia accompanies the respiratory complications and consciousness derangement after surgical operations more frequently than after spinal anesthesia. In this study, circulatory conditions during spinal anesthesia in elderly people (30-91 years old) were analyzed in 109 cases of spinal anesthesia. Hypotension occurred about 10 minutes and 40-60 minutes after injection of anesthetics and was frequent in patients of high aged group, but tachycardia was not observed among them. In addition, their blood pressure in the recovery room could not recover to the level before anesthesia. It is thought that hypotension during spinal anesthesia was induced by the vascular dilatation caused by sympathetic nerve block and the deficiency of reflective venous constriction in upper extremities and abdominal organs. Tachycardia may also produce hypotension. However, the reflexive vasoconstriction and tachycardia are thought to be poor on account of arteriosclerosis and down regulation of beta-receptor in elderly people. Therefore, during spinal anesthesia in the elderly people, the catecholamine released by the surgical stimulation could not increase blood pressure effectively. To prevent hypotension during spinal anesthesia in elderly people, it is advisable to employ the treatment for upregulation of beta-receptor before anesthesia and the administration of alpha . beta-receptor, epinephrine and dopamine for control of blood pressure during spinal anesthesia.