AIMS: This paper describes the pharmacokinetics and effects of propofol in 
short-term sedated paediatric patients.
METHODS: Six mechanically ventilated children aged 1-5 years received a 6 h 
continuous infusion of propofol 6% at the rate of 2 or 3 mg kg-1 h-1 for 
sedation following cardiac surgery. A total of seven arterial blood samples was 
collected at various time points during and after the infusion in each patient. 
Pharmacokinetic modelling was performed using NONMEM. Effects were assessed on 
the basis of the Ramsay sedation score as well as a subjective sedation scale.
RESULTS: The data were best described by a two-compartment pharmacokinetic 
model. In the model, body weight was a significant covariate for clearance. 
Pharmacokinetic parameters in the weight-proportional model were clearance (CL) 
= 35 ml kg-1 min-1, volume of central compartment (V1) = 12 l, 
intercompartmental clearance (Q) = 0.35 l min-1 and volume of peripheral 
compartment (V2) = 24 l. The interindividual variabilities for these parameters 
were 8%, < 1%, 11% and 35%, respectively. Compared with the population 
pharmacokinetics in adults following cardiac surgery and when normalized for 
body weight, statistically significant differences were observed the parameters 
CL and V1 (35 vs 29 ml kg-1 min-1 and 0.78 vs 0.26 l kg-1P < 0.05), whereas the 
values for Q and V2 were similar (23 vs 18 ml kg-1 min-1 and 1.6 vs 1.8 l kg-1, 
P > 0.05). In children, the percentage of adequately sedated patients was 
similar compared with adults (50% vs 67%) despite considerably higher propofol 
concentrations (1.3 +/- 0.10 vs 0.51 +/- 0.035 mg l-1, mean +/- s.e. mean), 
suggesting a lower pharmacodynamic sensitivity to propofol in children.
CONCLUSIONS: In children aged 1-5 years, a pharmacokinetic model for propofol 
was described using sparse data. In contrast to adults, body weight was a 
significant covariate for clearance in children. The model may serve as a useful 
basis to study the role of covariates in the pharmacokinetics and 
pharmacodynamics of propofol in paediatric patients of different ages.