Comparative Evaluation of Dexmeditomidine as an Adjuvant to 0.5% Ropivacaine in Supraclavicular Brachial Plexus Block for Upper Limb Surgeries : A Randomized Double Blind Controlled Interventional Study

The aim of giving anaesthesia to patients is performing safe and painless surgical and other medical procedures.

The upper extremity peripheral nerve blocks have been extensively used by anaesthetists for upper limb surgeries for decades. The peripheral nerve blocks have several benefits like better pain control, less undesirable side effects, and reduced hospital stay over general anaesthesia, thus providing a superior outcome. In peripheral nerve blocks, injection of the regional anaesthetic is given in the close vicinity of a specific nerve or bundle of nerves to block pain sensation generated and transmitted from a specific area of the body The local anaesthetic drugs block the transmission of pain signals from surgical site to the brain. Longacting local anaesthetic agents like bupivacaine and ropivacaine have been routinely used for upper limb surgeries in supraclavicular brachial plexus block. Ropivacaine is frequently used because it produces quick, dense, and prolonged block and has lesser side effects.

Due to the possibility of the effect of the local anaesthetic wearing out before the surgical period and causing severe pain, the volume of the local anaesthetic drug has been increased but it is associated with systemic side effects, particularly on the cardiovascular and nervous system. Therefore, several drugs such as opioids, nonsteroidal anti-inflammatory drugs NSAIDs, Alpha2-agonists, etc have been researched as adjunct agents to local anaesthetics. These are termed as analgesic

adjuvants. They increase the efficacy and duration of local anaesthetics and decrease the systemic side effects of a higher dose of local anaesthetic. However, the adjuvant itself may exhibit its own side effects such as hypotension, sedation, bradycardia, etc.

Dexmedetomidine is an Alpha 2 -adrenoreceptor agonist that has sedative, anxiolytic, and analgesic properties. Various studies have reported prolonged block and better postoperative analgesia with the administration of dexmedetomidine as an adjuvant to other local anaesthetics like bupivacaine or levobupivacaine.

However, there is very limited literature available on dexmedetomidine in combination with ropivacaine and the optimal dose of dexmedetomidine as an adjuvant in nerve blocks is still to be determined.

Furthermore, in clinical practice, none of the adjuvants is approved by the FDA. The use of such agents is completely off-label and depends on the assessment of risk to benefit ratio by the anaesthesiologists. Therefore, the debate regarding the advantages and disadvantages of using such an agents is a continuous topic discussion in the medical fraternity.

For this reason and with this background in mind, the present study will be designed with the aim for comparative evaluation of dexmedetomidine as an adjuvant to 0.5 percent ropivacaine in supraclavicular brachial plexus block for upper limb surgeries in terms of duration of analgesia, onset and duration of sensory and motor block, quality of block, duration of postoperative analgesia