Variability of plasma aprotinin concentrations in pediatric patients undergoing cardiac surgery.
OBJECTIVE
Infants and children undergoing cardiopulmonary bypass for repair of congenital heart defects are at substantial risk for excessive bleeding, contributing greatly to morbidity and mortality. Aprotinin significantly reduces bleeding and transfusion requirements in adults but is of indeterminate value for pediatric patients. The aim of this study was to determine plasma aprotinin concentrations in these patients with a functional aprotinin assay.


METHODS
Thirty patients less than 16 years of age scheduled for cardiac surgery with aprotinin were enrolled. Aprotinin was administered as a 25,000 KIU/kg bolus, 35,000 KIU/kg cardiopulmonary bypass prime, and 12,500 KIU.kg(-1).h(-1) continuous infusion. Blood samples for aprotinin concentrations (kallikrein-inhibiting units/milliliter) were obtained before aprotinin; 5 minutes post-bolus; 5 minutes after cardiopulmonary bypass initiation; 30 and 60 minutes on cardiopulmonary bypass; on discontinuation of aprotinin; 1 hour after aprotinin discontinuation; and 4 hours after permanent separation from cardiopulmonary bypass. For analysis, patients were grouped according to weight (<10 kg, 10-20 kg, >20 kg). Differences between weight groups were assessed using an exact test for categoric variables and 1-way analysis of variance for continuous variables.


RESULTS
Aprotinin concentrations differed significantly across weight groups. Five minutes after aprotinin bolus and initiation of cardiopulmonary bypass, there was significant correlation between weight and aprotinin concentration (r =.57, P =.003; r =.69, P =.001, respectively).


CONCLUSIONS
A functional assay reveals significant variability in aprotinin concentration for pediatric patients using current weight-based aprotinin dosing. Additional investigation is necessary to determine target aprotinin concentration dosing regimens to provide better efficacy.
Oliver
William C
WC
Department of Anesthesiology, Rochester, Minnesota 55905, USA.oliver.william@mayo.edu
Fass
David N
DN
Nuttall
Gregory A
GA
Dearani
Joseph A
JA
Schrader
Lisa M
LM
Schroeder
Darrell R
DR
Ereth
Mark H
MH
Puga
Francisco J
FJ
D000293:Adolescent; D007611:Aprotinin / Q000008:administration & dosage* / Q000493:pharmacokinetics*; D016063:Blood Loss, Surgical / Q000517:prevention & control*; D001835:Body Weight; D002315:Cardiopulmonary Bypass / Q000379:methods*; D002648:Child; D002675:Child, Preschool; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D005260:Female; D005500:Follow-Up Studies; D006330:Heart Defects, Congenital / Q000175:diagnosis / Q000601:surgery*; D006801:Humans; D007262:Infusions, Intravenous; D008297:Male; D016343:Monitoring, Intraoperative / Q000379:methods; D011300:Preoperative Care / Q000379:methods; D011336:Probability; D011446:Prospective Studies; D018570:Risk Assessment; D012720:Severity of Illness Index; D018709:Statistics, Nonparametric; D016896:Treatment Outcome
D007611:Aprotinin