Postoperative pain control
pain
All patients received intravenous sufentanil with an intravenous patient-controlled analgesia (PCA) system at the end of surgery. The mode of PCA was a bolus of sufentanil 0.05 μg/kg, a lockout time of 15 min, and a continuous infusion of sufentanil 0.04 μg/kg/h (total regimen 2 μg/kg/100 ml). The patients were taught to push the button of the PCA system to receive a bolus of sufentanil each time pain occurred. If the visual analog scale (VAS) score was ≥ 4, 40 mg parecoxib sodium was injected intravenously as a rescue analgesic.