Acute remifentanil exposure during intraoperative analgesia might enhance sensitivity to noxious stimuli and nociceptive responses to innocuous irritation. Cyclooxygenase inhibition was demonstrated to attenuate experimental remifentanil-induced hyperalgesia (RIH) in rodents and human volunteers. The study aimed to compare the effects of preoperative and postoperative flurbiprofen axetil (FA) on RIH after surgery.
Ninety patients undergoing elective laparoscopic gynecologic surgery were randomly assigned to receive either intravenous placebo before anesthesia induction (Group C); or intravenous FA (1.0 mg/kg) before anesthesia induction (Group F1) or before skin closure (Group F2). Anesthesia consisted off sevoflurane and remifentanil (0.30 μg/kg/min). Postoperative pain was managed by sufentanil titration in the postanesthetic care unit, followed by sufentanil infusion via patient-controlled analgesia. Mechanical pain threshold (primary outcome), pain scores, sufentanil consumption, and side-effects were documented for 24 hours postoperatively.
Postoperative pain score in Group F1 was lower than Group C. Time of first postoperative sufentanil titration was prolonged in Group F1 than Group C (P=0.021). Cumulative sufentanil consumption in Group F1 was lower than Group C (P<0.001), with a mean difference of 8.75 (95% confidence interval, 5.21-12.29) μg. Mechanical pain threshold on the dominant inner forearm was more elevated in Group F1 than Group C (P=0.005), with a mean difference of 17.7 (95% confidence interval, 5.4-30.0) g. Normalized hyperalgesia area was decreased in Group F1 compared to Group C (P=0.007). No statistically significant difference was observed between Group F2 and Group C.
Preoperative FA reduces postoperative RIH in patients undergoing laparoscopic gynecologic surgery under sevoflurane-remifentanil anesthesia.
*Tianjin Research Institute of Anesthesiology
†Department of Anesthesiology, Tianjin Medical University General Hospital, Tianjin, P.R. China
L.Z., H.W., and G.W.: conceived and designed the experiment. L.Z., R.S., Q.Z., and Y.L.: performed the experiment and collected the data. L.Z., C.W., and Y.Y.: analyzed the data. L.Z. and G.W.: wrote the paper.
Supported by research grants from the National Natural Science Foundation of China (81371245, 81301025, 81400908, and 81571077), Tianjin, China. The authors declare no conflict of interest.
Reprints: Guolin Wang, MD, Tianjin Research Institute of Anesthesiology and Department of Anesthesiology, Tianjin Medical University General Hospital, Tianjin 300052, P.R. China (e-mail: email@example.com).
Received February 29, 2016
Received in revised form August 5, 2016
Accepted July 4, 2016