Spinal anaesthesia is popularly used for lower abdominal and lower limb surgeries  because it provide good intraoperative conditions and early ambulation. Ropivacaine is a newer longer acting local anaesthetic structurally similar to bupivacaine with reduced cardiac and neurotoxicity . Our aim of study is to compare the Isobaric vs Hyperbaric preprations of Ropivacaine with Dexmedetomidine in terms of their efficacy, characteristics of block they produce, postoperative analgesia and safety.

Materials and Methods : It was Double blind study conducted on 60 patients, randomly divided into two groups each comprising (n=30) patients

 GpH– Hyperbaric Ropivacaine prepared by  0.75% 3ml (22.5mg) isobaric ropivacaine + 0.5ml of Dextrose 50% + 0.5ml of 15µg dexmedetomidine in 0.5 ml of normal saline=4ml

 GpI – Isobaric Ropivacaine 0.75% 3ml(22.5mg) + 0.5ml of normal saline + 0.5ml of 15µg dexmedetomdine = 4ml, Both groups were compared in terms of Mean Onset time of sensory and motor block  at T10 ,quality of anaesthesia, regression of sensory and motor block , duration of postoperative analgesia and incidence of any sideeffects such as hypotension, badycardia and respiratory depression.

 OBSERVATIONS AND RESULTS: Mean onset time of sensory analgesia at T10 level  in GP–H(6.4 ±3.53) vs (11.5 ±4.94 minutes)in GP–I(P<0.05) and  motor block grade–3 in GP–H

( 7.5±2.82minutes) vs (15.6±1.41minutes) In GP– I,onset is faster in GP–H. The mean time to complete regression of sensory block  was early in GP–H (238±2.82 min) vs (250±10.6 min) (p<0.05) . The mean time for complete motor regression was comparative (217.5±21.21 min) vs (225±21.21 min) (p>0.05) in both groups.  The total duration of analgesia was prolonged in both groups Gp–H 506minutes vs 449minutes GP–I .

CONCLUSION:GP–I is comparable to GP–H  in spinal anaesthesia for lower limb surgeries but GpH has faster onset, higher extent of spread, excellent quality and patient satisfactionfor operative procedures and prolonged postoperative analgesia.