A randomised controlled trial of intravenous dexamethasone combined with interscalene brachial plexus blockade for shoulder surgery.

We recruited patients scheduled for shoulder rotator cuff repair or subacromial decompression under general anaesthesia and interscalene brachial plexus blockade (30 ml ropivacaine 0.5%). We allocated 240 participants into four groups of 60 that were given pre-operative saline 0.9% or dexamethasone 1.25 mg, 2.5 mg or 10 mg, intravenously. We recorded outcomes for 48 h. The median (IQR [range]) time to first postoperative analgesic request after saline was 12.2 (11.0-14.1 [1.8-48]) h, which was extended by intravenous dexamethasone 2.5 mg and 10 mg to 17.4 (14.9-21.5 [7.2-48]) h, p < 0.0001, and 20.1 (17.2-24.3 [1.3-48]) h, p < 0.0001, respectively, but not by dexamethasone 1.25 mg, 14.0 (12.1-17.7 [2.1-48]) h, p = 0.05. Postoperative analgesia was given sooner after rotator cuff repair than subacromial decompression, hazard ratio (95% CI) 2.2 (1.6-3.0), p < 0.0001, but later in older participants, hazard ratio (95% CI) 0.98 (0.97-0.99) per year, p < 0.0001.