Postoperative analgesia by continuous extradural infusion of ropivacaine after upper abdominal surgery

Ropivacaine is a new local anaesthetic with advantages that suggest animportant role in the provision of postoperative analgesia. The main aim ofthis study was to investigate the dose-response relationship of extraduralinfusion of ropivacaine. We studied 36 ASA I-III patients undergoing upperabdominal surgery during general anaesthesia and extradural block (catheterinsertion at T6-9) using 0.5% ropivacaine in a randomized, double-blindstudy. After surgery nine patients each received an extradural infusion ofeither ropivacaine 0.1%, 0.2%, 0.3% or saline at a rate of 10 ml h-1 for 21h. All patients had access to i.v. morphine via a PCA device. Theropivacaine groups consumed significantly less morphine over the 21-hinfusion period than the saline group (medians: saline 75 mg; 0.1%ropivacaine 32 mg; 0.2% ropivacaine 39 mg; 0.3% ropivacaine 13 mg) (P <0.05). Pain (VAS scores) at rest was significantly lower in all ropivacainegroups than in the saline group after 4 h of infusion (medians: saline 45mm; 0.1% ropivacaine 15 mm; 0.2% ropivacaine 12 mm; 0.3% ropivacaine 0 mm).Pain on coughing was significantly less in all ropivacaine groups than inthe saline group after 4 h infusion (medians: saline 67 mm; 0.1%ropivacaine 44 mm; 0.2% ropivacaine 33 mm; 0.3% ropivacaine 0 mm) and for0.2% and 0.3% ropivacaine at later times. Motor block was negligiblethroughout the infusion. Patient satisfaction was higher in the 0.2% and0.3% ropivacaine groups than in the two other groups.