Original article / research
Efficacy of Dexmedetomidine as an Adjuvant to Ropivacaine plus Lignocaine-adrenaline Combination for Ultrasound-guided Popliteal Sciatic and Femoral Nerve Blocks in Lower Limb Surgeries: A Double-blinded Randomised Clinical Study
UC25-UC31
Correspondence
Neha Manoj Kushe,
Junior Resident, Department of Anaesthesiology, Krishna Vishwa Vidyapeeth (Deemed to be University), Karad, Maharashtra, India.
E-mail: nehakushe150217@gmail.com
Introduction: Single-injection peripheral nerve blocks provide effective perioperative analgesia for lower limb surgery, but the duration of local anaesthetic action may be insufficient for the early postoperative painful period. Dexmedetomidine may improve block quality when used as a perineural adjuvant.
Aim: To evaluate the efficacy of dexmedetomidine as an adjuvant to a ropivacaine plus lignocaine-adrenaline mixture for ultrasound-guided popliteal sciatic and femoral nerve blocks in patients undergoing below-knee lower limb surgeries.
Materials and Methods: This double-blinded randomised clinical study included 86 adults aged 18-60 years with American Society of Anesthesiologists Physical Status I-III. Patients were allocated into two equal groups. Group-RL received 20 mL of 0.5% ropivacaine and 10 mL of 2% lignocaine with adrenaline. Group-RLD received the same mixture with dexmedetomidine 5 microgram, with total volume maintained at 30 mL. Twenty millilitres was used for popliteal sciatic block and 10 mL for femoral nerve block. Sensory and motor onset and duration, time to first analgesic request, Visual Analogue Scale (VAS) scores, haemodynamic variables, sedation, satisfaction and adverse events were recorded. Continuous variables were expressed as mean±standard deviation and compared using independent t-test or appropriate non-parametric tests. Categorical variables were analysed using Chi-square test. A p-value <0.05 was considered statistically significant.
Results: Baseline characteristics were comparable between Group-RL and Group-RLD. Dexmedetomidine significantly shortened sensory onset (6.5±2.1 vs 9.8±2.6 minutes, p <0.001) and prolonged sensory duration (478.6±31.2 vs 332.7±24.5 minutes, p<0.001). Motor onset was faster in Group-RLD (8.3±2.8 vs 11.4±3.2 minutes, p<0.001), while motor duration was longer (289.4±34.7 vs 254.9±29.8 minutes, p<0.001). Time to first analgesic request was delayed with dexmedetomidine (528.3±33.5 vs 348.5±30.9 minutes, p<0.001). VAS scores were lower from two to 12 hours. Satisfaction rate was higher in Group-RLD (88.4% vs 55.8%, p<0.001). Bradycardia, hypotension and sedation were more frequent with dexmedetomidine, but no respiratory depression, local anaesthetic systemic toxicity, nerve injury or infection occurred.
Conclusion: Dexmedetomidine added to ropivacaine plus lignocaine-adrenaline for ultrasound-guided popliteal sciatic and femoral nerve blocks improved onset, prolonged sensory and motor block and enhanced postoperative analgesia, with a higher but manageable incidence of bradycardia, hypotension and sedation.