Double-blind trial comparing epidural lignocaine with epidural fentanyl for anaesthesia during extracorporeal shock wave lithotripsy.

A randomised double-blind trial was undertaken to compare epidural lignocaine 1.5% with adrenaline to epidural fentanyl (100 micrograms in saline 10 ml) in forty unpremedicated patients undergoing extracorporeal shock wave lithotripsy without ancillary procedures. Midazolam only was used for sedation. There was no significant difference in intraoperative pain scores with several patients in each group complaining of pain. Decreases in blood pressure occurred in both groups but were more pronounced in the lignocaine groups (36% vs 25% maximum decrease from control, P = 0.004). Heart rate was increased in the lignocaine group compared with control and to the fentanyl group, but there was no difference in respiratory rates within or between groups. Pruritus was more common in the fentanyl group and leg heaviness in the lignocaine group, but neither was troublesome. There was no difference in urological outcome at one month. Both techniques were satisfactory for the majority of patients, but the fentanyl group had a shorter preparation time and less cardiovascular changes.