Comparative study of supraclavicular axillary nerve block with or without clonidine as an adjuvant

Background: Local anesthetics administered as regional nerve blocks are utilized in providing postoperative pain relief in many surgical procedures by blocking signal traffic to the dorsal horn. Certain drugs like opioids, alpha2 adrenergic agonist, sodium bicarbonate, neostigmine, adrenaline, ketamine etc. are used as adjuvant to local anesthetics to lower doses of each agent and enhance analgesic efficacy while reducing the incidence of adverse reactions. Clonidine is a selective alpha 2 adrenergic agonist with some alpha 1 agonist property. In clinical studies, the addition of clonidine to local anesthetic solutions improved peripheral nerve blocks by reducing the onset time, improving the efficacy of the block during surgery and extending postoperative analgesia. In clinical studies, the addition of clonidine to local anesthetic solutions improved peripheral nerve blocks by reducing the onset time, improving the efficacy of the block during surgery and extending postoperative analgesia. Clonidine possibly enhances or amplifies the sodium channel blockade action of local anesthetics by opening up the potassium channels resulting in membrane hyper polarization, a state in which the cell is unresponsive to excitatory input. Material and methods: Present study was carried to evaluate efficacy of injection clonidine (150 ?g) as adjuvant to supraclavicular brachial plexus block (30 ml lignocaine adrenaline 1.5%, 10 ml bupivacaine 0.5%) in adult patients (ASA Grade I and II). Patients of both groups were assessed in terms of: Onset time of sensory blockade, Onset time of motor blockade, Perioperative hemodynamic status, Duration of post-operative analgesia, Time of 1st rescue analgesia, Adverse effects of drugs if any. Results: The mean time of onset of sensory and motor block was significantly lower in Group B compared to Group A. Mean duration of motor block and sensory block were significantly longer in Group B than in Group A. Mean time for analgesic requirement for Group B was 11.85 ± 1.54 hours and it was significantly longer than that in Group A (5.62 ± 0.358) hours (p <0.05). No incidence of nausea, vomiting, hypotension, tachycardia or bradycardia was observed in any group. One patient in Group B had pulse rate <60/min which was clinically not significant and did not require treatment. No incidence of decline in SPO2 perioperatively. Conclusion: When clonidine 150 ?g is added to local anesthetic solution in supraclavicular brachial plexus block, it provides rapid onset of block, better analgesia, good hemodynamic stability and profound and longer analgesia without any adverse effects. Clonidine is a good adjuvant to local anesthetic agent for brachial plexus block via supraclavicular approach for various upper limb surgeries.