ntrathecal Hyperbaric Bupivacaine 0.5% with Varying Dose of Buprenorphine in Elective Adult Lower Limb Orthopaedic Surgeries: A Randomised Control Study

Introduction: Postoperative pain is a universal phenomenon and usually under treated and its intensity varies widely among patients. Spinal anaesthesia with opioid and local anaesthetics to prolong postoperative analgesia is common practice in recent years. Buprenorphine is an agonist-antagonist opioid. Intrathecal buprenorphine (30-150 μg) along with local anaesthetics is safe and known to increase the postoperative analgesia without affecting sensory or motor blockade and with lesser side effects.

Aim: To compare the anaesthetic characteristics and its side effects in subarachnoid block with bupivacaine 0.5% heavy and varying dose of buprenorphine (90 μg and 120 μg).

Materials and Methods: This randomised control trial study was conducted in the Jhalawar Medical College, Jhalawar, Rajasthan, India, from March 2019 to November 2019. The study included 90 patients belonging to American Society of Anaesthesiologists (ASA) class I and II of either sex age between 18 to 60 years posted for elective lower limb orthopaedic surgeries. The patients were divided into three groups; group A which included a patient count of 30 received plain hyperbaric bupivacaine 0.5% (2.5 mL) with 0.5 mL saline. Group B which included 30 patients, receive plain hyperbaric bupivacaine 0.5% (2.5 mL) along with buprenorphine 90 μg diluted in 0.5 mL saline. Group C with a patient count of 30 received hyperbaric bupivacaine 0.5% (2.5 mL) with buprenorphine 120 μg mixed with 0.5 mL saline. Analgesic characteristics, haemodynamic parameters, side effects, sedation scores by Ramsay Sedation Score and pain scores by Visual Analogue Score (VAS) (0-10) were measured postoperatively till 24 hours.Statistical analyses of data were done by One-way Analysis of Variance (ANOVA) test and Chi-square test, where p-value less than 0.05 was considered to be a statistically significant value.

Results: The onset time of sensory blockade (group A: 5.14±1.34, group B: 4.54±1.10, group C: 4.50±1.18 in minutes), time of onset of motor blockade (group A: 10.10±1.00, group B: 9.43±1.30, group C: 9.21±1.49 in minutes) and maximum level of sensory block at T6 level (group A: n-01/30, group B: n-04/30, group C: n-04/30) were comparable between the three groups and were not statistically significant. Sensory recovery time was significantly (p<0.0001) delayed in group B and C (178.9±7.18 min and 189.23±7.4 min.), while in group A it was 152.86±8.9 min. Duration of postoperative analgesia was significantly (p<0.0001) prolonged in group C (group A 165.53±8.5, group B 391.49±19.8, group C 493.23±18 in minutes). Side-effects like Postoperative Nausea and Vomiting (PONV) and sedation were increased with dose of buprenorphine, but easily treatable and not significant (p>0.05).

Conclusion: A higher dose of buprenorphine shows to provide an adequate and longer postoperative analgesia without any major side effects.