小儿异丙酚靶控输注系统准确性的评价

Evaluation of the accuracy of administration of propofol by a TCI system in children

目的建立小儿异丙酚药代学参数的靶控输注(TCI)系统,评价系统的准确性。方法 24例ASA Ⅰ级择期手术小儿,分为2组(n=12),A组:≥3岁且<5岁;B组:≥5岁且<10岁,应用连庆泉等报道的小儿异丙酚药代动力学参数以及Stanpump软件,微机连接Graseby 3500输液泵。恒定血浆靶浓度3μg·ml-1变速输注持续1 h,间断采集动脉血持续1．5 h。用高效液相法测定异丙酚血浆药物浓度,并计算系统的执行误差中位数(MDPE)、不含TCI开始5 min的执行误差中位数(MDPE1)、执行误差绝对值的中位数(MDAPE)、分散度和摆动度。结果两组异丙酚的实测浓度在TCI开始40 min内均高于靶浓度(P<0．05),后渐接近靶浓度,至TCI 50 min时与靶浓度差异无统计学意义。停止 TCI后实测浓度比预测浓度低(P<0．01)。A、B组TCI期间系统的MDPE分别为27％和26％、MDPE1 分别为7％和12％、MDAPE分别为27％和26％、分散度分别为-0．75％·h-1和-0．80％·h-1、摆动度分别为23％和24％,停止TCI后系统的MDPE分别为-30％和-25％,MDAPE分别为30％和25％,摆动度分别为9％和9％,分散度分别为0．31％·h-1和0．38％·h-1。结论本研究中小儿TCI输注系统的偏离性较小,精确度较高且分散度小,能维持稳定的血药浓度,符合临床要求。

Objective To develop a target-controlled infusion （TCI） system incorporating population pharmacokinetics of propofol for children and evaluate its accuracy. Methods The TCI system was composed of a Samsung Q20 laptop computer, Graseby 3500 infusion pump, Stanpump software （Version 1.0 designed by Shafer et al. Stanford） and pharmacokinetic parameter set for propofol in children reported by Lian et al. Twenty-four ASA Ⅰ children undergoing elective orthopedic or urological surgery under general anesthesia were divided into 2 age groups- group A 3-5 yrs （ n = 12） and group B 5-10 yrs （ n = 12）. Radial artery and internal jugular vein were cannulated. The pediatric patients were sedated with ketamine 4mg·kg^-1 IM （uncooperative patients） or 2 mg·kg^-1 Ⅳ （cooperative patients）. Anesthesia was induced with fentanyl 3 μg·kg^-1, propofol by TCI and vecuronium 0.1mg·kg^-1. Target plasma concentration of propofol was set at 3 μg·ml^-1. TCI of propofol was maintained for 60 min. Arterial blood samples were taken at 1, 3, 5, 10, 20, 30, 40, 50 and 60min after TCI was started and at 2.5, 5, 10, 20 and 30 min after termination of TCI for determination of blood propofol concentration by HPLC. The median performance error （MDPE）, MDPE without first five minutes （MDPE1）, median absolute performance error （MDAPE）, wobble and divergence were calculated. Results During the first 40 minutes of TCI there was a remarkable difference between the measured plasma propofol concentration （Cm） and the target plasma concentration （Cp）. The difference was narrowing gradually until the 50 min of TCI. After the termination of TCI the Cm was significantly lower than Cp. The MDPE was 27% in group A and 26% in group B; MDPE1 was 7% （A） and 12% （B） and MDAPE 27% （A） and 26% （B） during TCI. The wobble was 23% （A） and 24% （B） and the divergence -0.75%·h^-1（A） and -0.80%·h^-1 respectively. Conclusion The bias and divergence of our TCI system for propofol are small and the accuracy is high and a stable plasma concentration of propofol can be maintained in children.