Effects of intraoperative high-dose vs low-dose remifentanil for postoperative epidural analgesia after gynecological abdominal surgery: a randomized clinical trial

Abstract Study objectives To evaluate whether intraoperative high-dose remifentanil infusion increased local anesthetic consumption in postoperative epidural analgesia and postoperative pain scores compared with low-dose remifentanil infusion. Design Prospective, randomized controlled study. Setting Operating room, university hospital. Patients Thirty female patients scheduled for elective gynecological abdominal surgery. Interventions After epidural catheter placement and induction of general anesthesia, patients were randomly assigned to 2 anesthetic regimens. In the first group (high-dose remifentanil group), sevoflurane concentration was held constant at 1.2%, and the remifentanil infusion rate was titrated to maintain systolic blood pressure within 20% of baseline. In the second group (low-dose remifentanil group), the remifentanil infusion rate was held constant at 0.1 μ g/(kg min), and the sevoflurane concentration was titrated to maintain systolic blood pressure within 20% of baseline. As abdominal wall closure began, 6 mL of 0.2% ropivacaine was administrated via epidural catheter; a patient-controlled analgesia device was set to deliver 4 mL/h of 0.2% ropivacaine with 3 μ g/mL of fentanyl, with 2-mL incremental doses and a 15-minute lockout time. Measurements Local anesthetic consumption via postoperative epidural catheter and pain intensity with the Prince Henry pain scale were assessed for 48 hours after surgery. Main results The mean remifentanil infusion rate was 0.23 μ g/(kg min) in the high-dose remifentanil group, 2.3 times the rate used in the low-dose remifentanil group. The cumulative amount of local anesthetic used within 48 hours of surgery was significant greater in the high-dose remifentanil group than in the low-dose remifentanil group (212 ± 25 mL vs. 181 ± 35 mL, respectively; P < .05), but postoperative pain scores were similar in each group. Conclusions Intraoperative high-dose remifentanil infusion increased local anesthetic consumption in postoperative epidural analgesia relative to low-dose remifentanil.