Patient-controlled regional analgesia (PCRA) with ropivacaine after arthroscopic subacromial decompression†

Background: The aim of the study was to evaluate postoperative analgesia and safety of wound instillation of ropivacaine either by a single dose or a patient-controlled regional anaesthesia (PCRA) technique. Methods: In 40 patients undergoing arthroscopic subacromial decompression the surgeon placed a catheter into the subacromial space at the end of the operation. In Phase I (10 patients), ropivacaine 250 mg was injected twice within 1 h. In Phase II, 30 patients were randomised into three groups: group prilocaine-ropivacaine (PR) = 20 ml of 1% prilocaine-epinephrine injected preoperatively into the subacromial bursa + 20 ml of 0.5% ropivacaine infused in the catheter postoperatively; group saline-ropivacaine (SR) = saline-epinephrine (20 ml) preoperatively + 0.5% ropivacaine as in group PR; group saline-saline (SS) = saline-epinephrine (20 ml) preoperatively + saline postoperatively. The PCRA pump was filled with local anaesthetic or saline to allow boluses of 10-ml each, maximum one bolus/h, via the catheter. Pain relief, side-effects and venous plasma concentration of ropivacaine were evaluated during a 24-h-test period. Results: The free plasma concentration of ropivacaine was 0.12 + 0.041 mg l−1 in Phase I. No adverse effects were seen. In Phase II pain at rest and on movement was lower in group PR than in group SS during the first 30 min postoperatively (P