Comparison of continuous and intermittent administration of extradural bupivacaine for analgesia after lower abdominal surgery.

We have compared intermittent bolus and continuous infusion of extradural local anaesthetic for pain relief in a randomized, double-blind study of 48 patients who underwent major abdominal gynaecological surgery. Each patient received 5 ml of 0.375% bupivacaine hourly, either as a bolus over 5 min or as a constant infusion. Patients who received the intermittent administration technique maintained a more extensive sensory block, reported marginally better analgesia and had a lower requirement for rescue medication. The intermittent bolus technique was not associated with an increase in side effects.