Comparison of Dexmedetomidine and Fentanyl as Adjuvants to Ropivacaine for Epidural Analgesia in Abdominal Hysterectomy: A Study on Postoperative Analgesia Quality.

Background and aim Ropivacaine, at lower concentrations, has been shown to provide effective postoperative analgesia. The addition of adjuvants enhances its analgesic efficacy without significantly increasing the risk of motor blockade. The study aimed to evaluate the analgesic adjuvant properties of epidural dexmedetomidine (1 µg/mL) and epidural fentanyl (2 µg/mL) when administered with 0.125% ropivacaine via a patient-controlled epidural analgesia (PCEA) pump in patients undergoing total abdominal hysterectomy (TAH). Methods A total of 60 patients scheduled for elective TAH were randomized into two groups in this prospective trial. Thirty patients were allocated to the ropivacaine with dexmedetomidine group (Group RD), and 30 patients were enrolled in the ropivacaine with fentanyl group (Group RF). Group RD received 0.125% ropivacaine with dexmedetomidine (1 µg/mL) as the study drug, whereas Group RF received 0.125% ropivacaine with fentanyl (2 µg/mL). Patients were administered general anesthesia after placement of a lumbar epidural catheter at the L3-L4 interspace, advanced 3-5 cm into the epidural space. One hour after skin incision, the study drugs were continuously infused through the epidural catheter using a syringe pump at a rate of 7 mL/hour. Following completion of surgery and extubation, PCEA pumps were connected to the epidural catheter, delivering a background infusion of 5 mL/hour, a bolus dose of 2 mL, and a lockout interval of 10 minutes. The background infusion was continued for 24 hours. Rescue analgesia with fentanyl (0.5 µg/kg) was planned if the Visual Analog Scale (VAS) score remained above three despite reaching the maximum permissible PCEA dose of 10 mL/hour. Postoperatively, patients undergoing TAH were monitored for total study drug consumption via the epidural route through PCEA, postoperative pain intensity (measured using VAS), the number of self-administered bolus doses via the PCEA pump, need for rescue analgesics, hemodynamic parameters, and other adverse effects. Results VAS pain scores were found to be statistically significant between the two groups at 4, 8, 12, 16, 20, and 24 hours postoperatively, with p-values of 0.034, 0.002, 0.004, 0.001, 0.005, and 0.023, respectively. The total drug consumption during and after surgery was 138.47 ± 2.67 mL for the RD group and 144.53 ± 4.19 mL for the RF group, with a p-value of 0.0001, indicating a highly significant difference. The average total number of bolus doses in 24 hours was 3.067 ± 1.23 in Group RD and 5.267 ± 2.09 in Group RF, with a p-value of 0.0001. Rescue analgesia was not required in either group, and no motor blockade was observed in any patient. Hemodynamic parameters were comparable between groups and did not show any significant changes. Conclusions The analgesic adjuvant properties of dexmedetomidine (1 µg/mL) were superior to those of fentanyl (2 µg/mL) when used with 0.125% ropivacaine. However, neither group required rescue analgesia, suggesting that both agents can be effectively used for TAH.