Comparison of epidural butorphanol and fentanyl as adjuvants in the lower abdominal surgery: A randomized clinical study

BACKGROUND: Epidural opioids acting through the spinal cord receptors improve the quality and duration of analgesia along with dose-sparing effect with the local anesthetics. The present study compared the efficacy and safety profile of epidurally administered butorphanol and fentanyl combined with bupivacaine (B). MATERIALS AND METHODS: A total of 75 adult patients of either sex of American Society of Anesthesiologist physical status I and II, aged 20-60 years, undergoing lower abdominal under epidural anesthesia were enrolled into the study. Patients were randomly divided into three groups of 25 each: B, bupivacaine and butorphanol (BB) and bupivacaine + fentanyl (BF). B (0.5%) 20 ml was administered epidurally in all the three groups with the addition of 1 mg butorphanol in BB group and 100 μg fentanyl in the BF group. The hemodynamic parameters as well as various block characteristics including onset, completion, level and duration of sensory analgesia as well as onset, completion and regression of motor block were observed and compared. Adverse events and post-operative visual analgesia scale scores were also noted and compared. Data was analyzed using ANOVA with post-hoc significance, Chi-square test and Fisher's exact test. Value of P < 0.05 was considered significant and P < 0.001 as highly significant. RESULTS: The demographic profile of patients was comparable in all the three groups. Onset and completion of sensory analgesia was earliest in BF group, followed by BB and B group. The duration of analgesia was significantly prolonged in BB group followed by BF as compared with group B. Addition of butorphanol and fentanyl to B had no effect on the time of onset, completion and regression of motor block. No serious cardio-respiratory side effects were observed in any group. CONCLUSIONS: Butorphanol and fentanyl as epidural adjuvants are equally safe and provide comparable stable hemodynamics, early onset and establishment of sensory anesthesia. Butorphanol provides a significantly prolonged post-operative analgesia.