Spinal anaesthesia with 0.75% bupivacaine and 0.5% amethocaine in 5% glucose

Three millititre of 0.75% plain bupivacaine and 0.5% amethocaine 3 ml in 5% glucose were used for spinal anaesthesia and compared in a double-blind study of 20 patients undergoing urological surgery. The onset time to maximum cephalad spread of sensory analgesia was approximately 45 min for bupivacaine and approximately 30 min in the amethocaine group (ns). The mean maximum spread of sensory analgesia was similar for both agents: T6-7 180 min after injection, although the cephalad spread of sensory analgesia with bupivacaine persisted for longer at a significantly higher level than that of amethocaine. Duration of sensory analgesia was significantly longer in the bupivacaine group from S3 to S5 and from T12 to L2 levels. Onset time to complete motor blockade of the lower limbs was similar for both agents. Nine of 10 bupivacaine patients and seven of the 10 patients receiving amethocaine had complete motor blockade of the lower limbs. Duration of motor blockade was significantly longer for all degrees in the bupivacaine group.