McFarlan C S, Anderson B J, Short T G
Department of Anaesthesia, Auckland and Starship Hospitals, New Zealand.
Paediatr Anaesth. 1999;9(3):209-16.
Children require higher infusion rates of propofol than adults to maintain clinical anaesthesia. We aimed to produce a manual infusion regimen capable of maintaining a steady-state blood concentration of 3 microg ml(-1) in children aged 3-11 years. Pharmacokinetic parameter estimates were taken from published studies of infusion data in children and used in a pharmacokinetic simulation programme to predict likely propofol blood concentrations during infusions. A variability of 5% was allowed about the target concentration of 3 microg ml(-1). A loading dose of 2.5 mg x kg(-1) followed by an infusion rate of 15 mg x kg(-1) x h(-1) for the first 15 min, 13 mg x kg(-1) x h(-1) from 15 to 30 min, 11 mg x kg(-1) x h(-1) from 30 to 60 min, 10 mg x kg(-1) x h(-1) from 1 to 2 h and 9 mg x kg(-1) x h(-1) from 2 to 4 h resulted in a pseudo-steady state target concentration of 3 microg x ml(-1) in children 3-11 years. We were unable to predict similar rates by applying size models to adult data. The context sensitive half-time in children was longer than in adults, rising from 10.4 min at 1 h to 19.6 min at 4 h compared to adult estimates of 6.7 min and 9.5 min, respectively. Children require higher infusion rates than adults to maintain steady state concentrations of 3 microg x ml(-1) and have longer context sensitive half-times than adults. These differences can be attributed to altered pharmacokinetics in this age group.
与成人相比，儿童需要更高的丙泊酚输注速率来维持临床麻醉状态。我们旨在制定一种手动输注方案，以维持3 - 11岁儿童3微克/毫升的稳态血药浓度。药代动力学参数估计值取自已发表的儿童输注数据研究，并用于药代动力学模拟程序，以预测输注期间丙泊酚可能的血药浓度。允许目标浓度3微克/毫升有5%的波动范围。负荷剂量为2.5毫克/千克，随后在最初15分钟内输注速率为15毫克/千克·小时，15至30分钟为13毫克/千克·小时，30至60分钟为11毫克/千克·小时，1至2小时为10毫克/千克·小时，2至4小时为9毫克/千克·小时，这样可使3 - 11岁儿童的伪稳态目标浓度达到3微克/毫升。通过将体型模型应用于成人数据，我们无法预测出类似的速率。儿童的情境敏感半衰期比成人长，从1小时时的10.4分钟升至4小时时的19.6分钟，而成人估计值分别为6.7分钟和9.5分钟。与成人相比，儿童需要更高输注速率来维持3微克/毫升的稳态浓度，且情境敏感半衰期更长。这些差异可归因于该年龄组药代动力学的改变。
