A Comparative Study Of Intrathecal Bupivacaine Alone And With Fentanyl And Dexmedetomidine As Adjuvants For Post-Operative Analgesia Under Spinal Anaesthesia

Background: Postoperative pain occurs due to the peripheral tissue injury which provokes peripheral and central sensitization. Several modalities have been developed, using analgesics and adjuvant drugs, to assure complete pain relief in perioperative period. Spinal anaesthesia, is a popular and common technique used worldwide, for lower limb and lower extremity surgeries. However, post-operative pain control is a major problem with using local anesthetics alone in subarachnoid block, because of relatively short duration of action. Regional techniques with adjuvant drugs are effective in control of post-operative pain. Objectives: This study is aimed at evaluating and comparing the efficacy of Fentanyl and Dexmedetomidine as adjuvants to 0.5% Bupivacaine, for post-operative analgesia in terms of- a. Onset and duration of sensory and motor block. b. Duration of post-operative analgesia. c. Observe side effects if any. Material & methods: This prospective, randomized, comparative, double-blind clinical study was conducted at St. Stephen’s Hospital, Delhi, on 90 patients between the age group of 15-70 years, belonging to ASA class I and II, who were to undergo any lower abdominal or lower limb surgery under subarachnoid block. The patients were randomly allocated into 3 groups of 30 each: Group B: Bupivacaine 0.5% 3.0ml + 0.5ml saline. Group F: Bupivacaine 0.5% 3.0ml + 0.5ml Fentanyl (25ug). Group D: Bupivacaine 0.5% 3.0ml + Dexmedetomidine (5ug) Results: 1. The mean duration of complete analgesia for group B was 150± 26 minutes, 215.3 ± 30.9 for group F and 252.2 ± 33.4 for group D. This was found to be stastically significant (p Value=0.00). 2. The mean duration of 1st analgesic medication requirement for group B was 182.03± 31.99 minutes, 255.1 ± 36.15 minutes for group F and 310.5± 38.6 minutes for group D. This was found to be stastically significant (p Value=0.00). 3. The incidence of Hypotension and Bradycardia was significantly higher in Group D as compared to group B and group F (P=0.002 and 0.002 respectively). 4. The incidence of Pruritus was significantly higher in group F as compared to group D and Group B (P=0.005). Conclusion: The conclusions that were drawn from the study can be summarized as follows: The addition of Dexmedetomidine may benefit patients undergoing lower limb surgery or lower abdominal surgeries under spinal anaesthesia in terms of prolongation of analgesic-time and reduction of analgesic dose without any major side effect.