[Influence of remifentanil on postoperative pain with intravenous patient-controlled analgesia following total knee arthroplasty].

BACKGROUND: There is a controversy about the development of acute opioid tolerance during remifentanil infusion for postoperative pain. We investigated whether intraoperative remifentanil infusion leads to rapid development of tolerance. We also investigated whether adjuvant analgesic is effective or not. METHODS: One hundred and thirty patients scheduled for TKA were divided into 4 groups; Non-remifentanil infusion group (30 patients; group A). This group was given a bolus of fentanyl 0.2 mg at the induction of anesthesia. In remifentanil anesthesia group (100 patients), remifentanil was given 0.2-0.3 microg x kg(-1) min(-1) and divided into three groups; 23 patients group B given a bolus of 0.2 mg fentanyl at induction of anesthesia, 38 patients group C given a bolus of fentanyl 0.2 mg at skin closure, and 39 patients group D given a bolus of fentanyl 0.2 mg at skin closure and administrated diclofenac sodium suppository rectally at induction of anesthesia. Intravenous patient controlled analgesia (PCA) of fentanyl was commenced before skin incision for all patients. Pain was scored at rest and during movement for 24 postoperative hours. RESULTS: Numerical rating scale (NRS) scores during movement after 24 hours in group B were significantly higher than in group A. And, the NRS scores in group D tended to be lower than the other groups, but there were no significant differences. CONCLUSIONS: Intraoperative remifentanil increased postoperative pain during movement. Remifentanil seems to cause acute torelance. NSAIDs given before operation may be useful for postoperative analgesia.