SPINAL-ANESTHESIA WITH 0.5-PERCENT HYPERBARIC BUPIVACAINE IN ELDERLY PATIENTS - EFFECT OF SITE OF INJECTION ON SPREAD OF ANALGESIA

In this randomized, observer-blind study, we have examined, in elderly patients, the effect of site of injection on analgesia levels after s pinal injection of 0.5% hyperbaric bupivacaine solution. Thirty male p atients, aged 68-87 yr, undergoing minor urological surgery during spi nal anaesthesia received 3 ml of a 0.5% hyperbaric bupivacaine solutio n at either the L3-4 (n = 15) or L4-5 (n = 15) interspace. The solutio n was injected with the patient in the sitting position. The patient r emained sitting for 2 min and was then placed in the supine horizontal position. Analgesia levels were assessed bilaterally using pinprick. The highest analgesia levels did not differ between groups (medians we re approximately T7). There were no significant differences in the tim e to maximum cephalad spread of analgesia, maximum degree of motor blo ck or haemodynamic changes. We conclude that injection at the L4-5 int erspace has no advantage compared with injection at the L3-4 interspac e.