Comparison of Fractionated Dose Versus Bolus Dose of Bupivacaine Hyperbaric (0.5%) with Buprenorphine in Spinal Anaesthesia for Lower Limb Surgeries

Background and Aims: Spinal anaesthesia (SA) stands as a widely utilised anaesthetic approach for patients undergoing surgeries involving the lower limb, lower abdomen, pelvis and perineum. This study aims to evaluate the safety of fractionated dose versus bolus dose injection of hyperbaric bupivacaine (0.5%) with buprenorphine in SA for lower limb surgeries concerning haemodynamic stability, total analgesia duration and the quality of sensory and motor blocks. Materials and Methods: A randomised controlled trial was conducted from January 2023 to January 2024 after obtaining approval from the Institutional Ethics Committee, adhering to ethical standards throughout the research process. A sample size of 54 per group was determined accounting for potential dropouts, considering a dropout rate of 10%. The criteria for participant selection were carefully established. Inclusion criteria encompassed patients who had undergone lower limb surgeries and had American Society of Anesthesiologists (ASA) physical status 1 and 2, were aged between 18 and 60 years, had a body mass index (BMI) falling within the range of 18.5 to 24.9 kg/m 2 , and had a height ranging from 150 to 180 cm. Results: In our investigation, we observed that five minutes after administering SA, the sensory level was notably elevated in the fractionated group, with a majority of patients (62.9%) reaching a level of T10. Simultaneously, the corresponding motor block, assessed using the modified Bromage score, predominantly showed a score of 4 in the fractionated group, with 77.10% of patients exhibiting this level, compared to 62.90% in the bolus group. By the 20-minute mark post-SA, the majority of patients in the fractionated group had sensory levels at either T8 or T10, while in the bolus group, an equal number of patients (40%) had reached these levels, and around 5.7% even displayed a level at approximately T6. Conclusion: In conclusion, when comparing the patients in Group F [fractionated dose of bupivacaine and buprenorphine] to those in Group B [bolus dose of bupivacaine and buprenorphine], the patients in Group F exhibited a higher level of haemodynamic stability.