Effect Of Dezocine On Median Effective Dose Of Fentanyl In Postoperative Analgesia

Objective: To explore the effect of dezocine on median effectivedose (ED₅₀) of fentanyl in patients for postoperative pain. Methods: Eighty-twopatients （ASAⅠ～Ⅱ）, aged18～65yr, body mass index18～25kg/m²wereenrolled to undergo orthopedic operation for extremities with general anesthesia.All the patients were allocated to group D₀, group D₁, group D₂and group D₃to receive dezocine at doses of0,0.1,0.2,0.3mg/kg. Postoperative analgesiawas measured by judging VAS score, while increasing or decreasing1ug/kg inthe following patient. The initial dose of fentanyl was identified by ED₅₀of theprevious one using up-and-down method. Calculate the ED₅₀and95%confidence interval of fentanyl in different groups. Results:1. All patients infour groups had no significant difference in demographics （gender, age, bodymass index） and operative time （P>0.05）.2. Four groups of patients at thevital signs （HR, RR, BP, SPO2）:（1）：Intergroup comparison:①Between thefour groups of HR, RR and SPO2had no significant difference at the same timepoint（P>0.05）;②The differences of SBP between the group D₀and the groupD₂were significant （P <0.05） at4h through48h in the postoperative time,while the group D₃below the group D₀at the point of postoperative4h（P <0.05）. Compared with group D₁, SBP of group D₂were lower in postoperativetime at12h,24h and48h points（P <0.05）;③Compared with group D₀, DBP of group D₂were lower at the points of4h,24h and48h in thepostoperative time（P <0.05）; Group D₃were also lower than group D₀inpostoperative time at4h,12h points（P <0.05）; Compared with group D₁, DBPof group D₂was lower at postoperative48h （P <0.05）;（2）Intra-groupcomparison：①Compared with preanesthesia, the results of HR, RR and SPO2in four groups had no significant difference in the postoperative time （P>0.05）.②The systolic blood pressure in postoperative time were lower thanpreanesthesia at group D₀that had a statistically significant difference. Thesystolic blood pressure of group D₂and group D₃also lower than preanesthesiarespectively, the difference was statistically significant.③The diastolic bloodpressure of preanesthesia was higher than postoperative opoint at24hpoint in group D₁（P <0.05）. Compared with preanesthesia, the postoperativeopoint at4h、12h、24h and48h points in group D₂and D₃were lower, GroupD₂and D₃of diastolic blood pressure at different time points after surgery werelower than preanesthesia, between the all points showed significantdifferentce（P <0.05）.3. Compared the doses of fentanyl for postoperativeanalgesia in four groups:①In the doses of fentanyl for postoperativeanalgesia aspects, there had a significant differences in the group of D₁、D₂、D₃to compared with the group D₀（P <0.01）.②Similarly, higher doses offentanyl was required in the group D₁, compared with the D₂and D₃groups.③The doses of fentanyl for postoperative analgesia between the two groups（D₂and D₃） showed no significant difference （P>0.05）.4. The ED₅₀and95%CI of fentanyl in group D₀, group D₁, group D₂and group D₃were as follows:11.91ug/kg（95%CI11.51～12.33ug/kg）,16.60ug/kg（95%CI15.21～18.11ug/kg）,14.79ug/kg（95%CI13.52～16.18ug/kg）,13.77ug/kg（95%CI13.52～14.03ug/kg）. Conclusion:1. Dezocine（0.1⁰.3mg/kg） mixed with fentanyl forpostoperative analgesia will increasing the ED₅₀of fentanyl, but with increasingdoses of dezocine, the ED₅₀of fentanyl has reduced tendency;2. Fentanylcombined with small doses of dezocine （0.1～0.3mg/kg） for postoperativeanalgesia showed antagonistic effects. The small doses of dezocine mixed withfentanyl for postoperative intravenous analgesia should be adjusted dosage offentanyl to achieve a good analgesic effcet.