Background: There are many adjuvants used along with bupivacaine for subarachnoid block, but Fentanyl and Clonidine are commonly used as adjuvants to intrathecal bupivacaine for prolonging both sensory and motor blockade as well as postoperative analgesia in patients undergoing lower limb orthopedic surgery. Aim: The aim of the present study was to compare the effect of intrathecal Clonidine and Fentanyl as adjuvants to Bupivacaine in the subarachnoid block for lower limb orthopedic surgery. Materials and Methods: 200 patients belonging to American Society of Anaesthesiologists I or II, scheduled for lower limb orthopaedic surgery under spinal anaesthesia were randomly allocated to one of the two following groups to receive Bupivacaine 15mg combined with 50

Background: Anaesthesia for the lower limb surgeries could be either general or regional. Studies had shown that regional anaesthesia for lower limb surgery results in better postoperative outcomes, including improved respiratory function, less nausea vomiting, less pain and lower incidence of deep vein thrombosis. Among all the regional anaesthetic techniques spinal anesthesia remained most preferred technique for its fast, predictable, profound, high quality sensory and motor block. However some complications like hypotension, bradycardia, post dural puncture headache, urinary retention were unavoidable and hypotension remained the most common one and found to be more in the elderly population with incidence of 25–82%. Treating spinal anaesthesia-induced hypotension included intravenous (IV) volume administration. IV Fluid infused before and at the time of spinal anaesthesia was referred to as preloading and coloading respectively. Although merit of coloading and the choice of fluid to be infused had remained  a matter of debate, till today no definitive study had indicated any superiority of colloids over crystalloids decisively  moreover large amount crystalloids to counter hypotensin  remained a threat to the cardiovascular overload for  elderly patients. Role of vasopressors in elderly remained controversial too. So this observational prospective study was  undertaken to compare  the effiicacy of coloading of infusion 6%HES 130/0.4 (colloid) and Ringer Lactate solution (crystalloid)  to maintain the intra operative haemodynamics in elderly patients undergoing lower limb orthopaedic surgery under spinal anaesthesia. Objectives: To assess and to compare the efficacy of infusion 6%HES 130/0.4 and infusion Ringer lactate solution coloading in preventing the intra-operative hypotension. Materials and method: On  approval of the Ethics Committee of Burdwan Medical College (BMC&H), 80 patients were included and equally divided into two groups group A and group B where groupp A received 6% HES  as coloading fluid and groupp B received RL as coloading fluid at the start of spinal anaesthesia. On entering Operation Theatre baseline parameters were noted for each patient and lumbar puncture for spinal anaesthesia was performed following strict aseptic precautions, in sitting position. Upon achieving adequate block episodes of hypotension were noted and treated according to the study protocol. Results: Statistical analysis for Continuous and categorical variables were done using Mann-Whitney U test and Pearson’s Chi Square test accordingly and p values less than 0.05 were considered significant. In group A, 17.5 % patients developed one episodes of hypotension whereas in group B, 37.5% patients developed one episodes of hypotension which was statistically significant with p value 0.0465.  In group A none of the patients developed further episodes of hypotension but in group B 5% affected patients developed one more episodes of hypotension and 2.5% affected patients developed two more episodes of hypotension. Average intravenous dose of mephentermine required to treat hypotension was 1.05 mg for group A and 2.70 mg for group B and found to be statistically significant with p value 0.039. Total fluid consumption In group A was 654.95 ml whereas in group B  was 976.73 ml and also  found to be statistically significant with p value <0.001. Conclusion:  The study found that coloading with 6% HES was significantly effective than Ringer Lactate solution in preventing episodes of hypotension in spinal anaesthesia induced elderly patients undergoing lower limb surgery without any noticeable adverse effect. Key Words: Spinal anaesthesia, lower limb surgery, elderly patients, coloading