Spinal anaesthesia has several benefits as it provides prolonged post-operative analgesic effect, has rapid onset and offset, easy administration, is pocket friendly, reliable, safe, patient is awake unlike in general anaesthesia and there is decreased risk of aspiration.

Earlier hyperbaric solutions of Levobupivacaine and Ropivacaine were prepared in operating room but now hyperbaric solutions of these drugs are available in the market in concentration of 0.5% and 0.75% respectively each combined with 80 mg of dextrose. The disadvantage of preparing these hyperbaric solutions in operating room was that density of each newly prepared solution was different, so the results could not be reproduced reliably.

Previous studies by Casati used Levobupivacaine and Ropivacaine by adding dextrose (30mg) in operating room and the specific gravities of the Hyperbaric Bupivacaine was 1.00874g/ml, Hyperbaric Levobupivacaine was 1.00945g/ml and Hyperbaric Ropivacaine was 1.00876g/ml.⁶

This can be compared with the newer preparations available of Hyperbaric Levobupivacaine which has specific gravity of 1.025-1.035 and Hyperbaric Ropivacaine which has specific gravity of 1.025-1.035. The newer preparations of both Hyperbaric Levobupivacaine and Hyperbaric Ropivacaine contains 80mg dextrose in each ml and have similar specific gravity.

As earlier studies on hyperbaric ropivacaine and levobupivacaine, solutions used were prepared by addition of dextrose prior to administration, so baricity was unreliable with specific gravity unknown. Hence, in this study, we aim to compare the efficacy of two newly available hyperbaric preparations of hyperbaric Levobupivacaine and hyperbaric Ropivacaine in lower limb surgeries.

 Spinal Anaesthesia will be administered to the patient in L2-L3 interspace with patient sitting using a midline approach using 25G spinal needle. According to randomization, patient will receive either preservative free formulation of hyperbaric ropivacaine 0.75% (3ml) or hyperbaric levobupivacaine 0.5% (3ml). No adjuvant medication will be added to either local anaesthetic.

After completion of the spinal injection, patient will be immediately made to lie supine with operating table horizontal. The patient will be evaluated for sensory and motor block, for every 2 minutes for first 20 minutes, every 3 minutes for next 30 minutes, every 10 minutes for 60 minutes, and finally every 15 minutes until the sensory block has regressed to S1 dermatome.

The patient will be administered Inj. Midazolam 1mg iv after spinal Anaesthesia has been given. During the surgery the patient’s pulse, Systolic Blood pressure, Diastolic Blood pressure, Mean Arterial Pressure, heart rate will be recorded every 3 minutes for 30 minutes and then every 5 mins for next 30mins and then 15mins until completion of the surgery.

The sensory level of the block will be assessed in a caudal to cephalad direction, using loss to pin prick sensation, and the C5-C6 dermatome is used as an unblocked reference point.