Impact of dexmedetomidine on effect-site concentration of propofol with target controlled infusion and hemodynamics during operation

Objective To evaluate effects of different doses of dexmedetomidine(Dex) on effect-site concentration (Ce) of propofol with target controlled infusion (TCI) and hemodynamics during operation.Methods A prospective,randomized,doubleblind and placebo controlled clinical protocol was used in this study.According to random number table,sixty patients (ASA Ⅰ-Ⅱ) undergoing laparoscopic cholecystectomy in total intravenous anesthesia were randomly allocated to three groups with 20 patients in each group.When the induction of anesthesia started,Dex 0.4 μg/kg (group Dexl),0.5 μg/kg (group Dex2) or the same volume of normal saline (group NS) was infused intravenously within 10 min.Meanwhile,all patients received the same method of induction and the maintenance of anesthesia.In three groups,the systolic blood pressure (SBP),heart rate (HR),and Ce of propofol were recorded before induction of anesthesia (T0),before skin incision (T1),1 min after pneumoperitoneum (T2),5 min after pneumoperitoneum (T3),10 min after pneumoperitoneum (T4),20 min after pneumoperitoneum (T 5),lifting of pneumoperitoneum after 5 min (T6).At the end of operation,the total dose of propofol was recorded.Results The SBP at T1 in group Dex2 was significantly higher than group NS (P＜0.01).Compared with baseline,the SBP in group NS was significantly lower at T1 and T6.The SBP in group Dex1 and Dex2 were significantly lower at T1,T5,T6.More propofol consumed in group NS [(716±209) mg] than that in group Dex1 and in group Dex2[(587±184) mg and(489±158) mg(P＜0.05)].In each time point,the propofol Ce in group Dex2 was significantly lower than group NS (P＜0.01).From T2 to T6,the propofol Ce in group Dex1 was significantly lower than group NS (T6 time point P＜0.05,other time points P＜0.01).The dosage of propofol decreased by 18％ and 32％ respectively when combined with Dex 0.4 μg/kg and 0.5 μg/kg.Conclusions Infusion of Dex in laparoscopic cholecystectomy can stabilize the hemodynamics while decreasing the propofol Ce and reducing the consumption of of propofol. Key words: Dexmedetomidine;  Propofol;  Target controlled infusion