A randomized, double blind, controlled study on the effects of addition of clonidine to bupivacaine used for patients undergoing spinal anaesthesia

Abstract

Background: Spinal anaesthesia provided by bupivacaine alone may be too short for the planned surgery. The addition of clonidine 1 μg/kg to bupivacaine provides a prolonged anaesthetic action. The aim of this randomized double-blinded controlled study was to investigate the effects of addition of low dose clonidine to hyperbaric bupivacaine 0.5%, for spinal anaesthesia in patients undergoing lower abdominal and lower limb surgeries, on analgesic efficacy, quality of block, duration of analgesia and adverse effects.

Methods: Forty adult ASA Grade I and II patients of either sex posted for lower abdominal and lower extremity surgeries were randomly divided equally in to clonidine or control group. Control group received intrathecal 3.5ml of 0.5% hyperbaric bupivacaine with 0.5 ml of normal saline and Clonidine group received identical volume of intrathecal clonidine 1 μg/kg with 0.5% hyperbaric bupivacaine.

Results: Average two level regression time (129.55 min) was significantly prolonged in clonidine group than in the control group (74.5 min). (p-value < 0.01) Mean time for post operative analgesia was significantly longer in clonidine group (8.8 hours) than in the control group (4.1 hours). (p-value < 0.01). Heart rate at 15 minute intervals compared to 2 minute intervals was significantly less in clonidine group. ( p-value < 0.05). Bradycardia, hypotension, urinary retention and headache did not require any therapeutic intervention

Conclusion: Adding clonidine 1 μg/kg to intrathecal bupivacaine prolongs the duration of spinal anaesthesia and analgesia. It is safe and is likely to be as effective as higher doses of bupivacaine without severe adverse effects.

Key words: Intrathecal; Clonidine; Bupivacaine; Postoperative pain; Spinal anaesthesia

DOI: 10.4038/slja.v19i1.1715

Sri Lankan Journal of Anaesthesiology Vol.19(1) 2011 pp.17-21