Comparison of three different concentrations of ropivacaine for postoperative patient-controlled thoracic epidural analgesia after upper abdominal surgery.

Background: Previous studies have reported the comparable efficacy of ropivacaine/fentanyl for patient-controlled epidural analgesia (PCEA). In our hospital, three different concentrations of ropivacaine solution (0.1%, 0.15%, 0.2%) in combination with 1 microg/mL fentanyl were available for PCEA. As some studies have reported a much higher incidence of motor block and opioid-related side effects with 0.2% ropivacaine in combination with 4 microg/mL fentanyl, it was our intent to analyze the data of our patients who had received PCEA after upper abdominal surgery. In addition to comparing the analgesic effects and the incidence of motor block and opioid-related side effects of these three different ropivacaine/fentanyl solutions, we also evaluated the workload of our pain staff. The main purpose of our study was to determine which of these three regimens of ropivacaine was most satisfactory with the least workload for the pain service staff.

Methods: In total, 33 patients who had received PCEA after upper abdominal surgery were included in the analysis. The number of patients in each ropivacaine/fentanyl group was 11 (group 1, 0.1% ropivacaine; group 2, 0.15%; group 3, 0.2%). The PCEA device was programmed to deliver a patient-controlled bolus of 2 mL with a lockout time of 20 minutes and background infusion of 5 mL/hr for 72 hours. Visual analog scale (VAS) pain scores, adverse events and the extent of sensory or motor block were recorded 12, 36 and 60 hours after surgery. The total volume of analgesic solution consumed and the frequency of requisite attendance by pain service staff were also recorded.

Results: There were no differences among the three groups regarding total consumption. In group 1, VAS scores during ambulation and cough 12 hours postoperatively were significantly higher than in the other two groups (p < 0.05). There was no motor block. Four patients in group 3 suffered from loss of temperature sensation. The overall incidence of adverse events was less than 40%.

Conclusion: Both thoracic epidural 0.15% and 0.2% ropivacaine provide effective postoperative pain control in combination with fentanyl without motor block. A 0.15% ropivacaine-1 microg/mL fentanyl solution is preferable considering the lower incidence of adverse events.