Evaluation of predictive performance of propofol target-controlled infusion system incorporating the Schnider pharmacokinetic parameters

Objective To evaluate the predictive performance of propofol target-controlled infusion (TCI) system incorporating the Schnider pharmacokinetic parameters in Chinese patients. Methods Forty ASA Ⅰ or Ⅱ patients, aged 25-45 yr, with body mass index 20-25 kg/m2 , scheduled for gynecological laparoscopic surgery un der general anesthesia, were enrolled in this study. Anesthesia was induced with TCI of propofol (target plasma concentration (Cp) 3 μg/ml) and remifentanil (Cp 4 ng/ml) . Propofol was infused by Orchestra TCI system incorporating the Schnider pharmacokinetic parameters. Tracheal intubation was facilitated with rocuronium 0.6 mg/kgafter the patients lost consciousness. The patients were mechanically ventilated. PETCO2 was maintained at 30-40 mm Hg. Anesthesia was maintained with TCI of remifentanil (Cp 4 ng/ml) and propofol (Cp 3-5 μg/ml) and intermittent iv boluses of atracurium 0.2 mg/kg. BIS value was maintained at 40-45. Venous blood samples were obtained at 15, 30, 45 and 60 min after pneumoperitoneum for measurement of blood propofol concentrations by high performance liquid chromatography with fluorescence detector. Performance error, median prediction performance error, median absolute performance error, wobble and divergence of propofol TCI system were calculated. Results The value for performance error was 21 % (13%), for median prediction performance error 6.7 % (37.4%),for median absolute performance error 19% (18%), for divergence - 0.65%/h (0.82%/h) and for wobble 16.3% (15.2% ) . Conclusion The accuracy of propofol TCI system incorporating the Schnider pharmacokinetic parameters is high in Chinese patients and its predictive performance is acceptable clinically. Key words: Propofol; Pharmacokinetics; Drug deliver systems