Minimum effective volume of 0.5 percent Ropivacaine and 2 percent Lignocaine mixture for ultrasound guided Retroclavicular Brachial Plexus Block: A Prospective Dose Finding Study

Combining faster onset lignocaine with other slower onset agents such as bupivacaine, levobupivacaine and ropivacaine can hasten the onset of the block. The minimum effective volume (MEV) and concentration of local anesthetics are key to maximizing the quality and safety of nerve blocks while minimizing risks such as local anesthetic systemic toxicity. Dose finding studies have been done using 0.5% bupivacaine and 0.5% ropivacaine in Retroclavicular Block (RCB). A clinically effective dose of combination of local anaesthetic (LA) for achieving an adequate block with retroclavicular approach is lacking. This study seeks to determine the MEV50 and MEV95 of a 3:2 mixture of 0.5% ropivacaine and 2% lignocaine in adults undergoing upper limb surgeries under the retroclavicular approach of infraclavicular block.