Target Controlled Infusion of Remifentainil in Elderly Patients:Assessment of Predictive Performance of Minto Parameters

Objective:To evalutate the performance of the target-controlled infusion system for remifentanil using minto pharmacokinetic parameters in Chinese old patients. Methods:Fifteen ASAⅠ-Ⅱpatients aged 65-75yr,body weight ranged from 50-71 kg, scheduled for surgery were enrolled in this study . The patients were unpremidicated . Left radial atery was cannu-lated for BP monitoring and blood sampling ,right subclavian vein was cannulated for drug and fluid administration. remifentanil (5 ng·mL-1)was given by TCI for 30 min. BIS,MAP,HR and SPO2 were continuosly monitored during the experiment. Blood samples were taken at 1,3,5,10,15,20,25 ,30min after the start of TCI for determination of blood remifentanil concentraion by HPLC-UV(Waters600). The performance were caculated by the median performance error(MDPE), the median absolute performance error(MDAPE)and Wobble. Results: the measured concentrations of remifentanil were significant lower than the predicted concentration during the experiment(P0. 05). When remifentanil TCI system (the pharmacokinetic set described by Minto)was steady ,the MDPE、MDAPE and Wobble were 16. 80% , 23. 85% and 11.29%,respectively. Conclusion:Though the measured remifentanil concentration is overpredicted by the TCI system incorporating Minto pharmacokinetic parameter,the performance is acceptable in Chinese old patients.