COADMINISTRATION OF PETHIDINE AND CLONIDINE - A SPINAL ANESTHETIC TECHNIQUE FOR TOTAL HIP-REPLACEMENT

Co-administration of pethidine 0.75 mg kg(-1) and clonidine 75 mu g in trathecally provided good intraoperative anaesthesia for total hip rep lacement, similar to that obtained using 0.5% isobaric bupivacaine. Se nsory and motor block were of shorter duration than that after 0.5% is obaric bupivacaine and 0.5% isobaric bupivacaine with morphine 0.5 mg (P < 0.001 sensory block, P < 0.001 motor block). Postoperative morphi ne consumption, measured using a patient-controlled system, was simila r to that in patients in the bupivacaine only group (pethidine-clonidi ne: median 39 mg/24 h; bupivacaine: median 34 mg/24 h) but greater tha n that in the bupivacaine-morphine group (median 8 mg/24h) (P < 0.001) . Visual analogue pain scores after operation were similar to those wi th bupivacaine alone at all but one of the recording times but were gr eater than those in patients who received bupivacaine and morphine at 4, 6 and 10 h after operation (P < 0.001, P < 0.04, P < 0.02). The com bination did not offer any major advantage over conventional agents.