Does epidural clonidine improve postoperative analgesia in major vascular surgery?

Aim To determine the quality and duration of the analgesic and haemodynamic effects of clonidine when used as an additional analgesic for postoperative epidural analgesia in major vascularsurgery. Methods The prospective, single-blinded study involved 60 patients randomised into three groups (20 patients each): Group BM—bupivacaine 0.125% and morphine 0.1 mg/ml; Group BC—bupivacaine 0.125% and clonidine 5 μg/ml; Group MC—morphine 0.1 mg/ml and clonidine 5 μg/ml continuously infused at 5 ml/h. The quality and duration of the analgesia measured by the Visual Analogue Scale (VAS) at rest and on movement, additional analgesia requirements, sedation scores, haemodynamic parameters and side effects(respiratory depression, motor block, toxic effects, nausea and pruritus) were recorded. Results The average VAS scores at rest and on movement were significantly lower in Group MC at two, six and 24 hours following the start of epidural infusion (P<0.05). The duration of the analgesic effect after finishing the epidural infusion was significantly longer in Group MC (P<0.05). Patients from Group MC were intubated longer. Additional analgesia consumption, sedation scoresand haemodynamic profiles were similar in all three groups. Prurituswas more frequent in morphine groups (P<0.05), but other sideeffects were similar in all three groups.Conclusion Under study conditions, clonidine added to morphine,not 0.125% bupivacaine, provided significantly better pain scoresat two, six and 24 hours following the start of epidural infusionand the longest-lasting analgesia following the discontinuationof epidural infusion. However, patients from the Group MC weremechanically ventilated longer than patients from other two groups.Continuous monitoring of the patient is necessary after theadministration of clonidine for epidural analgesia.