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.
© 2015 The Association of Anaesthetists of Great Britain and Ireland.