[Investigation of 121 cases of spinal anesthesia with plain 0.5% bupivacaine]

Bupivacaine has been used for spinal anesthesia since 1982 in our department. We performed a retrograde investigation of 121 cases who had lower limb surgery and anesthetized with plain 0.5% bupivacaine solution during the year of 1987. Doses of bupivacaine, maximum spread of analgesia and spinal tap level were analyzed. We chose the bupivacaine doses from 2.5 ml to 4.0 ml depending on the condition of the patient and the specificity of the surgery. The patients were divided into 3 groups by the dose of bupivacaine: i.e. 3.0, 3.5, 4.0 ml of plain 0.5% bupivacaine. Seventy percent of all patients had a spinal tap on L3/4 interspace. The average upper level of analgesia was T7 in each group and no patient had analgesia above T2 level. There was no correlation between the site of injection and volume of local anesthetics. However patient's physical status and surgical procedure are more important to obtain the good analgesic level. There was no significant respiratory depression nor hypotension during and after the surgery. It is concluded that 3-4 ml of 0.5% bupivacaine provided satisfactory spinal anesthesia for the lower limb surgery.