Effects Of Different Blood Plasma Target Concentrations Of Remifentanil Combined With Propofol On Cellular Immune Function In Patients Undergoing Radical Operation For Lung Cancer

Objective: To investigate the effects of different traget concentrations of remifentanil combined with propofol on immune function in the patients undergoing radical operation for lung cancer in terms of T-lymphocyte subpopulations,natural killer cells and cytokines.Methods: Twenty-four ASAⅡ～Ⅲpatients aged 35～64 yr and weigh index<30 kg·m^-2 udergoing radical operation for lung cancer were randomly allocated into three groups with eight cases in each group respectively. The patients were given midazolam 0.05mg·kg-1 and artropine 0.5 mg·kg-1 intravenously when they came into the operating room.Perioperative monitoring included electrocardiogram and heart rate (HR),noninvasivel mean arterial blood pressure(MAP),systolic blood pressure(SBP),diastolic arterial blood pressure(DBP),peripheral oxygen saturation(SpO2),bispectral index(BIS),and PETCO2 .Anesthesia was induced with remifentanil and propofol which were both given by TCI system simultaneously(pharmocokinetic parameters reported by Minto and Marsh were used respectively).The target concentration of propofol was set at 3μg·ml^-1 and remifentanil at 4,6,8 ng·ml^-1(groupâ… ,â…¡,â…¢).When the patients lost conscionsness ,vecuronium 0.1mg·kg^-1 was given intravenously to facilitate intubation.The patients were mechanically ventilated and PETCO2 were maintained between 30～40 mm Hg.Anesthesia was maintained with TCI of remifentanil combined with propofol and intermittent intravenously boluses of vecuronium. The target concentrations of remifentanil were not changed during anesthesia .BIS index was maintained between 45～55 by modifing the target concentration of propofol.When the surgery was completed ,the remifentanil and propofol infusions were stopped abrutly.When patients gained their consciousness and satifying spontaneous respiration (respiratory rate>10breaths/min,PETCO2<50mm Hg),the trachea was excubated.All the patients received patient controlled intravenously anesthesia (PCIA) immediately after the termination of propofol and remifentanil(normal saline 100 ml with fentanyl 10ug·kg-1 and lappaconitine 20 mg included).Venous blood samples were collected at the following times:before induction of anesthesia(T0),1h after the beginning of operation(T₁), immediately after termination of operation(T₂),24h(T₃) and 48h(T₄)after the end of operation.The blood samples were collected for determination of the expression of CD3+,CD4+,CD8+ on T-lymphocyte and CD3-CD16+CD56+ on natural killer cells by flow cytometry and calculation of proportion of CD4+ and CD8+,serum concentrations of IFN-r and IL-4 were detected by ELISA).Results: Patients'conditions were similar in the three groups before induction of anesthesia. As compared to the baseline value(T0) :the CD3+% was significantly decreased in both three groups (at T₃ point in groupâ… ,at T₂ and T₃ point in groupâ…¡,at T₁,T₂ and T₃ points in groupâ…¢);the expression of CD4+ was decreased immediately after termination of operation(T₂)in groupâ…¢;the expression of CD3-CD16+CD56+ was decreased in groupâ…¢(at T₁ and T₂ point);the proportion of CD4+ and CD8+ was increased in groupâ… (at T₁ point);Serum IFN-r concentration was significantly decreased after termination of operation(at T₂ point) in groupâ…¢and was significantly lower in groupâ…¢than in groupâ… andâ…¡,while the serum IL-4 concentration was decreased 1h after skin incision( at point T₁) in groupâ… ,the proportion of IFN-r and IL-4 was significantly decreased in both groupâ… andâ…¢and was significantly lower in groupâ…¢than in groupâ… andâ…¡.Conclusion: Remifentanil anesthesia combined with propofol could contribute to the immunosuppresion and could direct T helper cells toward Th2 differentiation, 8 ng·ml^-1 remifentanil administration would be more effective in suppresion of immunity than 4 and 6 ng·ml^-1 concentration of remifenanil,howerver these effects could recover fastly after operation.A selective narcotic analgesic and modertate analgesia after operation could be positive for the protection of cellular immnne function of the patients especially with tumour .