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

Abstract

Study objectivesTo 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. DesignProspective, randomized controlled study. SettingOperating room, university hospital. PatientsThirty female patients scheduled for elective gynecological abdominal surgery. InterventionsAfter 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 0.1μg/(kg min), and the sevoflurane concentration was titrated to maintain systolic blood pressure within 20% of baseline. As abdominal wall closure began, 6mL of 0.2% ropivacaine was administrated via epidural catheter; a patient-controlled analgesia device was set to deliver 4mL/h of 0.2% ropivacaine with 3μg/mL of fentanyl, with 2-mL incremental doses and a 15-minute lockout time. MeasurementsLocal anesthetic consumption via postoperative epidural catheter and pain intensity with the Prince Henry pain scale were assessed for 48hours after surgery. Main resultsThe mean remifentanil infusion rate was 0.23μg/(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 48hours of surgery was significant greater in the high-dose remifentanil group than in the low-dose remifentanil group (212±25mL vs. 181±35mL, respectively; P<.05), but postoperative pain scores were similar in each group. ConclusionsIntraoperative high-dose remifentanil infusion increased local anesthetic consumption in postoperative epidural analgesia relative to low-dose remifentanil.