Study on parecoxib sodium alleviating postoperative acute pain in patients with lower limb fracture undergoing remifentanil anesthesia

Objective: To observe the effect of parecoxib sodium on the level of plasma prostaglandin E₂(PGE₂) and β-endorphine(β-EP),and to explore the mechanism related to parecoxib sodium alleviating postoperative acute pain in patients with lower limb fracture undergoing remifentanil anesthesia.Methods: Sixty inpatients undergoing lower limbs fracture were randomly assigned into 3 groups.The patients in group A received a preoperative dose of normal saline 10 ml by intravenous administration.Group B received a preoperative dose of parecoxib sodium 40 mg(saline 10 ml) by intravenous administration before the operation.Group C received parecoxib sodium 40 mg before the operation,and received parecoxib sodium 40 mg every 12 h till 48 h after operation.Patient controlled intravenous analgesia was started 30 min before the end of operation,with the model(load volume 5 ml,continuous infusion at 1.5 ml/h,and bolus 0.5 ml at locked time 10 min).Analgesia mixture was consisted of fentanyl 15 μg/kg(total volume 100 ml).Visual analogue scale was recorded at 1,12,24,48 h after the operation.Valid/invalid presses,the need for additional analgesia drug within 48 h after the operation were recorded.The concentration of PGE₂ and β-EP were determined at before anesthesia induction(T₁),1 hour after the operation(T₂),24 hours after the operation(T₃),48 hours after the operation(T₄).Results: The patients among three groups were not significantly different in demographics and doses of narcotic(P>0.05).Compared with group A,Visual analogue scale scores in group B and group C significantly decreased.Presses in Patient controlled intravenous analgesia in group C were least in three groups(P<0.05).Plasma PGE₂ in group B and C at T₂,T₃,T₄ significantly decreased than group A(P<0.05 to P<0.01).Plasma β-EP in group C at T₃,T₄ were higher than that in group A and B(P<0.05 to P<0.01).Conclusions: Parecoxib sodium could heighten the effect of opioids,and significantly relieve the postoperative acute pain in patients with lower limb fracture undergoing remifentanil anesthesia.The underlying mechanism may be related to release of endogenous β-EP and inhibition of PGE₂ release.