Safety and Duration of Low-Dose Adjuvant Dexamethasone in Regional Anesthesia for Upper Extremity Surgery: A Prospective, Randomized, Controlled Blinded Study.

BACKGROUND Orthopedic procedures concerning the upper extremity commonly use a brachial plexus nerve block to achieve postoperative analgesia. The addition of dexamethasone to peripheral nerve blocks has been shown to significantly prolong its effect. We hypothesize that 1 mg doses of dexamethasone will prolong brachial plexus nerve block with similar efficacy to 4 mg and better than ropivacaine alone. METHODS Seventy-nine patients who received a brachial plexus nerve block prior to undergoing upper extremity surgery were randomized to 1 of 4 treatment groups: group 1 received only 30 mL of 0.5% ropivacaine without dexamethasone (control); groups 2, 3, and 4 received 4, 2, and 1 mg of dexamethasone, respectively, added to 30 mL of 0.5% ropivacaine. RESULTS Comparison of block duration, specifically "first signs of the block wearing off" to the 0-mg group, referencing the 1-, 2-, and 4-mg groups (P = .02, .04, and .01, respectively) that received steroid adjuvant therapy demonstrated a significant increase in time until the block began to wear off. All study groups receiving steroids also demonstrated a significant increase in duration of the block prior to its effects being completely gone when compared with the control group (P < .01 for all groups). CONCLUSIONS Our findings demonstrate that adjuvant dexamethasone can prolong brachial plexus nerve blocks effectively at low doses compared with high doses, in addition to prolonging analgesia compared with local anesthetic alone.