To investigate the dose-response relationship of flurbiprofen for inhibiting postoperative hyperalgesia after remifentanil-based anesthesia in patients undergoing major abdominal surgery.

Fifty patients undergoing major abdominal surgery under remifentanil-based general anesthesia were studied. Anesthesia was induced with midazolam 0.05 mg/kg, propofol 2 mg/kg, fentanyl 4 μg/kg and cisatracurium 1 mg/kg and maintained with infusion of remifentail(0.25 μg·kg^-1·min^-1) and propofol(3-4 mg·kg^-1·h^-1). Cisatracurium was given intermittently. The patients were mechanically ventilated after tracheal intubation. Flurbiprofen was given before skin incision for inhibiting remifentanil-induced postoperative hyperalgesia. Pain was assessed using VAS at 10 min after tracheal extubation. VAS score <4 was defined as effective. The optimal dose was determined by Dixon’s up-and-down method. If the VAS score was<4, the next patient received a lower dose of flurbiprofen, or conversely if ineffective, a high dose was given in the next patient. The up-and-down sequences were analyzed by using probit method that determine the ED50, ED95 and 95% confidence interval(CI).

The ED50 and ED95 of flurbiprofen for inhibiting postoperative hyperalgesia after remifentanil-based anesthesia in patients following gynecological laparoscopy were 1.40(95% CI=1.13- 1.61)mg/kg and 2.21(95% CI=1.89-3.33)mg/kg.

The ED50 and ED95 of flurbiprofen for inhibiting postoperative hyperalgesia after remifentanil-based anesthesia in patients following major abdominal surgery are 1.40 mg/kg and 2.21 mg/kg respectively.