Comparison of intrathecal bupivacaine-fentanyl and bupivacaine-butorphanol mixtures for lower limb orthopedic procedures

CONTEXT: Intrathecal use of butorphanol is less explored in human subjects. AIMS: To compare the safety and efficacy of anesthesia and analgesia of intrathecal bupivacaine-butorphanol mixture with intrathecal bupivacaine-fentanyl mixture. SETTINGS AND DESIGN: Tertiary level, teaching hospital. Prospective, randomized, double-blind study MATERIALS AND METHODS: Eighty patients aged above 18 years, of ASA physical status 1 or 2, undergoing lower limb orthopedic surgeries were randomly allocated to two groups of 40 patients each. Patients in group A and group B received intrathecal 2.5 ml of hyperbaric bupivacaine (0.5%), with 25 μg of fentanyl and 25 μg of butorphanol, respectively. STATISTICAL ANALYSIS USED: Fisher's exact test and Chi square tests RESULTS: The times required for onset of sensory and motor blockade were comparable among the two groups. Significantly slower block regression to S2 level was observed in the group receiving intrathecal butorphanol as compared to intrathecal fentanyl (P=0.0230). A higher number of patients in group A requested for rescue analgesia during the postoperative period than in group B (9 versus 2; P=0.0238). The average times to first request for rescue analgesia were 308.6±14.9 minutes and 365.9±12.3 minutes in group A and B, respectively (P=0.0254). CONCLUSIONS: Both 25 μg fentanyl and 25 μg butorphanol given intrathecally along with 12.5 mg of hyperbaric bupivacaine provide effective anesthesia for lower limb surgeries. Intrathecal bupivacaine-butorphanol mixture provides longer duration of sensory blockade and superior analgesia than intrathecal fentanyl-bupivacaine mixture.