Comparison of three solutions of ropivacaine/fentanyl for postoperative patient-controlled epidural analgesia

Background: Ropivacaine, 0.2%, is a new local anesthetic approved for epidu ral analgesia. The addition of 4 mu g/ml fentanyl improves analgesia from e pidural ropivacaine, Use of a lower concentration of ropivacaine-fentanyl m ay further improve analgesia or decrease side effects. Methods: Thirty patients undergoing lower abdominal surgery were randomized in a double-blinded manner to receive one of three solutions: 0.2% ropivac aine-4 mu g fentanyl, 0.1% ropivacain-2 mu g fentanyl, or 0.05% ropivacaine -l pg fentanyl for patient-controlled epidural analgesia after standardized combined epidural and general anesthesia. Patient-controlled epidural anal gesia settings and adjustments for the three solutions were standardized to deliver equivalent drug doses. Pain scores (rest, cough, and ambulation), side effects (nausea, pruritus, sedation, motor block, hypotensiofi, and or thostasis), and patient-controlled epidural analgesia consumption were meas ured for 48 h, Results:All three solutions produced equivalent analgesia. Motor block was significantly more common (30 vs. 0%) and more Intense with the 0.2% ropiva caine-4 mu g fentanyl solution, Other side effects were equivalent between solutions and mild in severity. A significantly smaller volume of 0.2% ropi vacaine-4 mu g fentanyl solution was used, whereas the 0.1% ropivacaine-2 m u g fentanyl group used a significantly greater amount of ropivacaine and f entanyl. Conclusions: Lesser concentrations of ropivacaine and fentanyl provide comp arable analgesia with less motor block despite the use of similar amounts o f ropivacaine and fentanyl, This finding suggests that concentration of loc al anesthetic solution at loa. doses is a primary determinant of motor bloc k with patient-controlled epidural analgesia after lower abdominal surgery.