Comparative study of postoperative analgesia intrathecal addition of fentanyl versus clonidine in lower limb surgeries

Background: Local anesthetic drugs like bupivacaine are commonly used in spinal anesthesia for lower limb surgeries but the duration of spinal anaesthesia is very short. However, the duration of action of bupivacaine in spinal anaesthesia can be prolonged by using adjuvants such as midazolam, opioids, neostigmine, dexmedetomidine and clonidine. The present study is being undertaken to evaluate and compare the effects of clonidine and fentanyl as intrathecal adjuvants to hyperbaric bupivacaine in patients undergoing lower limb orthopaedic surgery. Material and Methods: Present study was conducted in the Department of Anaesthesiology and Intensive Care, Government Medical College, Jammu in patients of either sex ranging in age from 20-60 years belonging to ASA I/ II scheduled for lower limb orthopaedic surgeries. 90 patients were randomly allocated in three groups of 30 each in order to compare the duration and quality of analgesia of clonidine and fentanyl used as adjuvants to intrathecal bupivacaine. Results: All the three groups were comparable in age, gender, height, weight, ASA grade distribution and the difference between them was not statistically significant. The difference between the time to reach the T10 block, mean time taken for first request for analgesia and duration of motor block in all three groups were found out to be statistically significant (p<0.0001). It was found that group with clonidine had better results than fentanyl and bupivacaine alone. In our study 1 patient in bupivacaine (15mg) with fentanyl (25µg) group and 2 patients in clonidine(37.5ugm) group had hypotension but the difference was statistically insignificant. Only 1 patient in each fentanyl and clonidine group had 1 episode of bradycardia but no patient in bupivacaine alone group had bradycardia and the difference was also insignificant. Postoperative vomiting was experienced by 3.33% of patients receiving Bupivacaine (15mg) with fentanyl (25µg) and it was treated by giving injection Ondansetron 4 mg i/v whereas no case was reported in clonidine group. This difference was statistically insignificant. 2 patients in bupivacaine (15mg) with fentanyl (25µg) group had itching but no such case was reported in clonidine group and the difference was also statistically insignificant. No respiratory depression, nausea was noted in study patients. Conclusion: It can be concluded that intrathecal clonidine (37.5ugm) provides quicker onset and prolonged duration of sensory and motor blocks simultaneously increasing the duration of analgesia when compared to fentanyl (25ugm).