Comparative Study of Low and High Doses of Butorphanol as Adjuvant to Bupivacaine in Subarachnoid Block

The goal of present study is to compare intraoperative and postoperative hemodynamic and sensory/ motor effects of low dose intrathecal butorphanol with bupivacaine versus high dose intrathecal butorphanol with bupivacaine in patients undergoing elective lower limb surgeries. Methods: This randomized, double blind comparative study was conducted in 60 patients belonging to ASA grade I or II, aged 20-60 years admitted for lower limb surgeries under spinal anesthesia. The patients were randomly divided into 2 groups. (A and B, n=30 for each group). Group A received combination of 0.5% hyperbaric bupivacaine (2.5 ml) with low dose butorphanol (25 microgram in 0.5 ml) intrathecally and group B received combination of 0.5% hyperbaric bupivacaine (2.5 ml) and high dose butorphanol (50 microgram in 0.5 ml) intrathecally. Preoperative and intraoperative vitals; side effects; intensity of motor blockade, time of onset of sensory and motor blockade; time taken for peak sensory and motor blockade; time for two segment sensory regression and time for rescue analgesia were compared in both group. Results: Time taken for peak sensory block was significantly lesser in group B and time for two-segment regression of sensory level and time to rescue analgesia were also significantly higher in group B, in which high dose intrathecal butorphanol-bupivacaine mixture was used. There was no difference in time taken to onset of sensory block, time taken to onset of motor block, time taken for peak motor block and in the intensity of motor blockade in using high dose intrathecal butorphanol-bupivacaine mixture as compared to low dose intrathecal butorphanolbupivacaine mixture. Conclusion: We concluded that high dose intrathecal butorphanol (50 μgm) with bupivacaine is well tolerated and potentiates the sensory block better than low dose intrathecal butorphanol (25 μgm) with bupivacaine with out any major side effects. It did not increase postoperative motor block recovery time and has delayed the postoperative analgesic requirement.