A comparative study between Clonidine and Buprenorphine as adjuvants to 0.5 percent Ropivacaine in Ultrasound guided Infraclavicular Brachial Plexus Block

General anaesthesia was one of the most common methods employed to provide anaesthesia for upper limb surgeries. With the introduction of newer and safer local anaesthetics and better advantages, regional anaesthesia has taken over as the principal technique for upper limb surgeries.

Regional anaesthesia is comparatively safer and does not involve the potential side effects and complications that may arise from sedation and general anaesthesia. It is also effective as it more acceptable amongst the patients, thus providing the doctors an increased patient compliance and consent for surgery. The infraclavicular block is a safe and effective approach for Brachial plexus block that can provide anaesthesia for hands, wrist and forearm.

 Ropivacaine is a propyl analogue of bupivacaine that has the same potency with longer duration of action and lesser cardiac and central nervous system toxicity of bupivacaine. Several adjuvants can be used to lengthen the duration of infraclavicular brachial plexus block such as clonidine, opioids, neostigmine, midazolam and buprenorphine[1].

 Clonidine, a selective alpha-2 adrenergic agonist inhibits nociceptive impulses by activating postjunctional alpha-2 adrenoreceptors both at peripheral and spinal nerve endings. It improves block characteristics of local anaesthetics in peripheral nerve blocks without producing any side effects like sedation, bradycardia and hypotension as seen in spinal blocks[2].

 Buprenorphine is a dehydroxylated phenanthrene and is chemically similar to other opioids such as hydrocodone, oxycodone, levorphanol, hydromorphone, oxymorphone, and others. Buprenorphine is a partial agonist at the m-opioid receptor (MOR) and an antagonist at k receptors. As a partial agonist, buprenorphine is able to activate MORs at low to moderate doses and it can achieve the same or superior analgesia compared to a full m-opioid agonist [3].

 There are studies that compare the effects of adding clonidine as an adjuvant to ropivacaine or bupivacaine for brachial plexus blocks[1]. But there are limited studies with buprenorphine as an adjuvant in infraclavicular blocks.

After thorough research in literature, it was concluded that limited data is available that compares and assess the effects of these drugs as adjuvants to ropivacaine.

Hence, this study is being undertaken which intends to compare and evaluate the effects of clonidine and buprenorphine as adjuvants to ropivacaine in infraclavicular brachial plexus blocks.