A Comparative Study of Analgesic Efficacy of Epidural Ropivacaine With Dexmedetomidine Versus Ropivacaine With Ketamine in Adult Patients Undergoing Elective Lower Limb Surgery

Introduction: Adjuvating of the epidural block with local anaesthetics during lower limb surgeries improves Intraoperative as well as postoperative analgesia. A comparison of epidural ropivacaine plus dexmedetomidine (RD) versus ropivacaine plus ketamine (RK) was done in terms of quality of the motor and sensory blockade, changes in hemodynamic parameters, and efficacy of analgesia. Methods: A prospective randomized parallel double-blind study was conducted on 68 patients of the American Society of Anaesthesiologists (ASA) grade 1 and 2, ages 18 to 75 years, which were divided into two groups (RD and RK; 34 patients in each group). After receiving a loading dose through an epidural catheter consisting of 20ml of 0.5% ropivacaine, the epidural infusion was started after an hour of surgery at 5ml/hrs of 0.2% ropivacaine with 1µg/ml dexmedetomidine in Group RD and at 5ml/hrs of 0.2% ropivacaine with 0.5mg/ml ketamine in Group RK for 48 hours. Both groups were compared regarding the onset of sensory and motor block, resolution of sensory and motor block, hemodynamic parameters, analgesic efficacy, and total rescue analgesic requirement in 48 hours. Results: A significant difference was observed in the time of resolution of sensory blockade which was 9.77±2.38 hrs in the RD group as compared to 7.79±1.82 hrs in the RK group (p-value 0.0003) and the time of resolution of motor block was 6.53±2.44 hrs in the RD group compared to 4.58±0.83 hrs in the RK group (p-value 0.001). Conclusions: Epidural dexmedetomidine significantly increases the duration of analgesia and duration of the motor blockade in comparison to ketamine.