Effects of different target plasma concentrations of propofol by target-controlled ifusion on end-tidal sevoflurane concentration

Objective To investigate the effects of different target plasma concentrations of propofol given by target-controlled ifusion(TCI) on end-tidal sevoflurane concentration.Methods Sixty ASAⅠor Ⅱ patients undergoing elective upper abdominal surgery under general anesthesia were randomly allocated to one of three groups with 20 patients in each group: group S,sevoflurane;group P1,sevoflurane +TCI propofol(1 μg·mL-1) and group P2;sevoflurane +TCI propofol(2 μg·mL-1).Anesthesia was induced with midazolm 0.05 mg·kg-1,fentanyl 3 μg·kg-1 propofol 0.5-1.0 mg·kg-1.Tracheal intubation was facilitated with vecuronium 0.12 mg·kg-1.After intubation anesthesia was maintained with sevoflurane inhalation alone(group I) or sevoflurane combined with TCI propofol at target plasma concentration of 1 μg·mL-1(group P1) or 2 μg·mL-1(group P2).Bispectral index(BIS) was maintained at 45-55 after tracheal intubation during maintenance of anesthesia.Results When BIS was maintained at 50±5,the end-tidal sevoflurane concentration was(1.74±0.14)%(group S),(1.24±0.08) %(group S) and(0.82±0.09)%(group P2),respectively.There was no singnificant difference in the heart rate at each time point among three groups,but arterial pressure was lower in the group P1 than that of two other groups.Conclusion At the same depth of anesthesia(BIS = 50 ± 5),the end-tidal sevoflurane concentration was greatly reduced when combined with TCI propofol,and TCI 1 μg·mL-1 propofol combined with sevoflurane can provides stable hemodynamic condition.