Improved postoperative analgesia with morphine added to axillary block solution

STUDY OBJECTIVE: To determine whether the addition of morphine to the axillary block local anesthetic solution provides improved or prolonged postoperative analgesia. DESIGN: Prospective, randomized, double-blind clinical trial with 24-hour follow-up. SETTING: Ambulatory unit of a large academic referral center. PATIENTS: Consecutive healthy volunteers scheduled for elective upper extremity surgery. INTERVENTIONS: Patients in the treatment group (AX) were given intravenous (IV) saline and had morphine 0.1 mg/kg added to their axillary block solution. Control subjects (CT) received morphine 0.1 mg/kg IV and had saline added to their axillary block solution. All axillary blocks were performed using 0.55 ml/kg of 1.5% lidocaine with epinephrine 1:200,000. MEASUREMENTS AND MAIN RESULTS: During the first 24 hours after surgery, visual analog scale (VAS) scores, supplementary analgesic (oxycodone 5 mg with acetaminophen 500 mg) use, and complications were recorded. Both groups had similar VAS scores throughout the study. In the 24-hour postoperative study period, AX patients required approximately half as many doses (median, 2 doses; range, 0 to 7 doses of supplemental analgesic as CT patients (median, 4 doses; range, 0 to 12 doses). There were no major complications in either group. CONCLUSIONS: The addition of morphine 0.1 mg/kg to the local anesthetic axillary block solution provided improved postoperative analgesia without an increased frequency of side effects or major complications.