A comparison of intrathecal Dexmeditomidine and Buprenorphine as an adjuvants to isobaric spinal 0.75% Ropivacaine in patients undergoing elective lower limb surgery

Introduction: Ropivacaine is the single enantiomer specific local anaesthetic having reduced potential for cardiotoxicity and neurotoxicity. Its characteristics of slow onset, shorter duration of sensory analgesia and rapid motor recovery will nesseciates for early analgesic intervention. Adding adjuvants to ropivacaine improves the efficacy of subarachnoid block. Drugs like dexmedetomidine, a highly selective alpha 2 adrenergic agonist and buprenorphine an opioid agonist and antagonist have been used as effective adjuvants. Aim: To evaluate and compare whether the small dose of adjuvants buprenorphine and dexmedetomidine added to isobaric spinal ropivacaine prolongs the duration of sensory and motor block as well as the duration of postoperative analgesia. The adverse effects and hemodynamic variable were also studied. Materials and Method: The study included 90 patients aged between 20-60 years belonging to either American Society of Anesthesiologists (ASA) Physical Status I/II scheduled for elective lower limb surgeries. The patients were randomly allotted to three groups. Group RS -received intrathecal 3ml of 0.75% ropivacaine with 0.5ml of normal saline. Group RB received 3ml of 0.75% ropivacaine with 60µg of buprenorphine. Group RD -received 3ml of 0.75% ropivacaine with 5µg of dexmedetomidine. The onset time to peak sensory level, onset of complete motor block (modified Bromage 3), duration of sensory and motor block, hemodynamic variables, and adverse effects if any were noted. Results: There was no difference between groups regarding demographic data and duration of surgery. Duration of sensory and motor block was significantly prolonged with Dexmeditomidine when compared with buprenorphine or saline (P<0.001). Dexmeditomidine delayed the time for first analgesic requirement postoperatively (P<0.001). No significant side effects were observed. Hemodynamic parameters were stable. Conclusion: Intrathecal dexmeditomidine as adjuvant to ropivacaine has shorter sensory onset time and is associated with prolonged duration of sensory and motor block and prolonged the time for first analgesic demand when compared with buprenorphine or plain ropivacaine with good hemodynamic stability and no significant side effects.