A comparitive study of plain Bupivacaine and combination of bupivacaine with Ondansetron as an adjuvant in supraclavicular brachial plexus block

Abstract

Background and objectives:Adjuncts to local anaesthetics for brachial plexus block may enhance the quality and duration of analgesia. Ondansetron, highly selective and potent antagonist of 5-hydroxytryptamine subtype 3 (5-HT3) receptors is known to produce antiemetic and in addition above effect it blocks sodium channel and has antinociceptive property to enhance the effect of local anaesthetic when given in peripheral nerve blocks. The purpose of this study was to assess the effect of Ondansetron added to brachial plexus block by supraclavicular approach. Methods:A prospective, randomized, single blinded study was conducted on 60ASA Grade I or II adult patients undergoing upper limb surgeries under supraclavicular brachial plexus block. Patients were randomly divided into two groups. Patients in Group A (n = 30) were administered 30mL of 0.5% Bupivacaine and Group B (n = 30) were given 30mL of 0.5% Bupivacaine with Ondansetron 8mg/kg. The onset time and duration of sensory and motor blockade were recorded. Haemodynamic variables (i.e., heart rate, blood pressure and oxygen saturation), sedation scores and rescue analgesic requirements were recorded for 24 hr postoperatively. Results: The onset of sensory and motor block was significantly faster in Group B compared to Group A (p< 0.05). The duration of sensory and motor block was significantly longer in Group B compared to Group A (p < 0.05). Rescue analgesic requirements were significantly less in Group B compared to Group A (p< 0.05). Haemodynamics and sedation scores did not differ between the two groups in the post-operative period. Conclusion: Ondansetron (8mg) in combination with 30mL of Bupivacaine (0.5%) hastened onset of sensory and motor block, and improved postoperative analgesia when used in brachial plexus block, without producing any adverse events.