Patient-controlled epidural analgesia versus continuous epidural analgesiaafter total knee arthroplasty

Background: Patient-controlled epidural analgesia (PCEA) has been found to be an effective method for pain relief during labour and after surgery. The goal of this study was to compare the efficacy of bupivacaine-fentanyl PCE A and continuous epidural infusion with the same mixture for treatment of p ain after total knee arthroplasty. Methods: Fifty-four patients under spinal anaesthesia were allocated to two groups in this randomized, double-blind study: the PCEA group could demand a bolus of 0.05 ml/kg of the bupivacaine 1.1 mg/ml and fentanyl 5 mug/ml s olution, with a lockout interval of 10 min and total dose limit of three bo lus doses per hour. The EPI group received a continuous infusion of 0.1 ml kg(-1) h(-1) of the same bupivacaine-fentanyl solution, and only a minimal extra bolus dose of 0.2 ml with the same lockout interval. All the patients received also paracetamol 1 g, orally, three times a day. In addition to p ain scores at rest and during leg lifting, the 20-h analgesic consumption a nd the incidence of side effects were recorded. Results: Forty-nine patients completed the study. The bupivacaine and fenta nyl consumption during 20 h was smaller in the PCEA group (P<0.001). Analge sia and the need for rescueopioid medication were similar in both groups. T here were no differences between the PCEA and EPI groups regarding the inci dence of side effects. Five patients were confused about how to operate the PCEA apparatus. Conclusion: The amount of bupivacaine-fentanyl solution consumed was signif icantly less with PCEA than with continuous infusion of bupivacaine-fentany l solution without affecting the quality of postoperative analgesia after t otal knee arthroplasty. Several of the elderly patients had difficulties in operating the PCEA apparatus.