Pharmacokinetic model-driven infusion of fentanyl in children.
BACKGROUND
This study determined the accuracy of previously defined adult fentanyl pharmacokinetics in children having surgery; from this population, the pharmacokinetics of fentanyl were characterized in children when administered via a computerized assisted continuous-infusion device.


METHODS
Twenty children between the ages of 2.7 and 11 y scheduled to undergo elective noncardiac surgery were studied. After induction, anesthesia was maintained with 60% nitrous oxide in oxygen supplemented with fentanyl (n = 10) or fentanyl plus isoflurane (n = 10). Fentanyl was administered via computerized assisted continuous-infusion to target concentrations determined by clinical requirements. Plasma fentanyl concentrations were measured and used to evaluate the performance of the fentanyl pharmacokinetics and then to determine a new set of pharmacokinetic parameters and the variance in the context-sensitive half-times simulated for these patients.


RESULTS
The original adult fentanyl pharmacokinetics resulted in a positive bias (10.4%), indicating that measured concentrations were mostly greater than predicted. A two-compartment model with age and weight as covariates provided the optimal pharmacokinetic parameters. These resulted in a residual performance error of -1.1% and a median absolute performance error of 17.4%. The context-sensitive times determined from this pediatric population were considerably shorter than the context-sensitive times previously published for adults.


CONCLUSIONS
The pharmacokinetics of fentanyl administered by computerized assisted continuous-infusion differ between adults and children. The newly derived parameters are probably more suitable to determine infusion schemes of up to 4 h in children between the ages of 2 and 11 y.
Ginsberg
B
B
Department of Anesthesiology, Duke University Medical Center, Durham, North Carolina 27710, USA.
Howell
S
S
Glass
P S
PS
Margolis
J O
JO
Ross
A K
AK
Dear
G L
GL
Shafer
S L
SL
D018686:Anesthetics, Intravenous / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D002648:Child; D002675:Child, Preschool; D003201:Computers; D005283:Fentanyl / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D006801:Humans; D008954:Models, Biological
D018686:Anesthetics, Intravenous; D005283:Fentanyl