Efficacy of Intrathecal Fentanyl and Butorphanol for Lower Limb Orthopedic Surgery: A Randomized Comparative Study

ABSTRACT

Intrathecal opioids when added to local anaesthetics decrease their dosage and provide haemodynamic stability. Subarachnoid block is a common anesthesia procedure for lower abdominal or lower limb surgeries including perineal surgeries. Objectives: To assess the efficacy of anesthesia and analgesia between intrathecal fentanyl and butorphanol with bupivacaine heavy 0.5% for lower limb orthopaedic surgery. Methods: About 120 patients, aged 18-75 years, belonging to American society of anesthesiologists (ASA) physical status 1 or 2 and scheduled for elective, lower limb orthopedic surgeries was randomized into two groups. Group A received 2.5ml of 0.5% hyperbaric bupivacaine with 0.5ml (25μg fentanyl) a total volume of 3ml intrathecally. The Butorphanol was diluted using distilled sterile water to obtain 25μg in 0.5ml. This was then added to 2.5ml of 0.5% hyperbaric bupivacaine to make a total volume of 3ml which was given to group B. 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<.001). A higher number of patients in group A requested for rescue analgesia during the postoperative period than in group B (11 versus 3; P=0.0326). The average times to first request for rescue analgesia were 254.47±9.31 minutes and 291±8.45 minutes in group A and B, respectively (P<0.001). Conclusion: Both 25μg fentanyl and 25μg 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.