Individualizing aminophylline doses in premature infants using bioelectrical impedance: a non-invasive approach.
The role of bioelectrical impedance (BI) in estimating the pharmacokinetics and, therefore, individualized doses, of aminophylline in preterm infants (gestational age 26-35 weeks) was assessed in a two-phase study. Multiple regression analysis in the first group of neonates (phase I, n = 19) identified resistance, reactance, weight and length as optimal predictors of distribution volume (adjusted R2 = 0.84, coefficient of variation (CV) = 10.17%), and length2/impedance and postconceptual age as predictors of clearance (adjusted R2 = 0.74, CV = 26.73%). Application of these models to an independent group (phase II, n = 20) generated doses which satisfactorily achieved target theophylline loading and steady-state (SS) 'peaks' of 10 micrograms/mL and SS 'troughs' of 7.7 +/- 0.6 micrograms/mL. A better understanding of specific criteria and limitations of the impedance technique in neonates is necessary in order to refine BI measurements.
Sidhu
J
J
Department of Pharmacy, University of Queensland, Australia.
Triggs
E
E
Charles
B
B
Tudehope
D
D
Gray
P
P
Cowley
D
D
D000628:Aminophylline / Q000008:administration & dosage* / Q000097:blood / Q000493:pharmacokinetics*; D001049:Apnea / Q000188:drug therapy* / Q000378:metabolism; D002110:Caffeine / Q000493:pharmacokinetics; D017097:Electric Impedance; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D007235:Infant, Premature, Diseases / Q000188:drug therapy* / Q000378:metabolism; D008297:Male; D008657:Metabolic Clearance Rate; D008954:Models, Biological; D012044:Regression Analysis
D000628:Aminophylline; D002110:Caffeine