Comparison of the Effects of Adding Dexamethasone at 0.25% Ropivacaine With 0.5% Ropivacaine Alone in the Supraclavicular Brachial Plexus Block

The supraclavicular brachial plexus block is widely used in upper limb surgery below the shoulder. Although it is easier and more stable than axillary nerve block and subclavian brachial plexus block, long-acting local anesthetics are used for long-term blockade with traditional block methods. However, this can easily lead to long-term motor nerve blockage, Horner's syndrome, phrenic nerve paralysis or systemic poisoning, and even serious side effects such as cardiac arrest.

Ropivacaine is a novel long-acting topical amine amine topical anesthetics that lasts long and has anesthetic and analgesic effects. Its pharmacological characteristics are low cardiotoxicity, sensory block and motor block separation at low concentrations more obvious, and with the external peripheral vasoconstriction. Therefore, the drug is especially suitable for postoperative analgesia. Dexamethasone is a synthetic corticosteroid for the treatment of a wide range of symptoms including rheumatic diseases, certain skin diseases, severe allergies, asthma, chronic obstructive pulmonary disease, cerebral edema, and may also be combined with antibiotics for tuberculosis patients. It is becoming more common to use steroids as an adjunct to local anesthetics in brachial plexus block. Steroids have neurological blockade effects by blocking the nociceptive transmission of pith-type C-fibers and inhibiting the release of ectopic neurons. Dexamethasone, as a local anesthetic adjuvant in peripheral nerve block, has also been widely studied recently.

In order to reduce the incidence of long-acting topical anesthetics from the nerve block in the supraclavicular arm, reducing the local anesthetic concentration is a feasible method, but this will also result in a shorter time to neurological block. The investigators hypothesized that the addition of Dexamethasone 5 mg to low concentrations (0.25%) of Ropivacaine would prolong postoperative analgesia. Therefore, the purpose of this study was to compare the postoperative analgesia and the side effects of postoperative supraclavicular brachial plexus blockade with the addition of Dexamethasone 5mg to Ropivacaine (0.5%) alone and Ropivacaine (0.25%) in low concentrations.