Effects Of Different Target Controlled Concentrations Of Remifentanil On Sevoflurane MAC_BAR In Patients With B-grade Liver Function Undergoing Laparoscopic Surgery

Objective:1.To observe in the process of CO₂ pneumoperitoneum whether there is a difference between patients with normal liver function and grade B liver function in sevoflurane MAC_BAR?2.To investigate the effect of different plasma concentration of remifentanil on the MAC_BAR of sevoflurane in patients with B-grade liver function?3.The changes of epinephrine,norepinephrine,heart rate and blood pressure in the blood at the corresponding point of MAC_BAR will be measured?Methods:One hundred patients,including twenty five patients with normal liver function and seventy five patients with child-pugh grade B liver function,aged 18 to 65 years old,BMI?kg/m²?<30kg/m²,were selected for laparoscopic hepatobiliary surgery,which was divided into normal liver function group?group N?and grade B liver function group?group R?.The plasma concentration of remifentanil in group N was 0ng/ml,the group R was randomly divided into 3 subgroups?group R₀,R₁and R₂?with 25 cases in each subgroup and the plasma concentration of remifentanil was0ng/ml,1ng/ml,and 2ng/ml,respectively.Propofol 2-4mg/kg,remifentanil2ug/kg and cis-atracurium 0.15mg/kg were intravenously administered for anesthesia induction.Preset inhaled concentration of sevoflurane was given in all groups after intubation,and maintained stable for 20 min to observe the hemodynamic response to pneumoperitoneum stimulation.Sevoflurane MAC_BAR was measured by sequential method,and plasma catecholamine concentration was measured before and after pneumoperitoneum stimulation.Results:In the group N,R₀,R₁ and R₂,the MAC_BAR of sevoflurane was?5.33+0.21?%,?4.83+0.14?%,?3.00+0.15?%and?2.10+0.20?%,respectively.A significant difference in the MAC_BAR of sevoflurane was found between group N and group R₀?P<0.05?,and also found among group R₀,R₁ and R₂?P<0.05?.Target controlled infusion of remifentanil 1 ng/ml and 2ng/ml decreased the MAC_BAR of sevoflurane in patients with B-grade liver function by 38%and 57%,respectively.There were no significant differences in the concentrations of epinephrine and norepinephrine in the blood among the four groups when a half of the adrenergic response was inhibited.Conclusion:Liver dysfunction and different target controlled concentration of remifentanil also can reduce the MAC_BAR of sevoflurane during laparoscopic surgery.However,The levels of adrenal and norepinephrine in the blood were not affected by the status of liver function and the concentration of remifenanil by target controlled infusion when a similar degree of stress response was inhibited.