Pharmacokinetic/pharmacodynamic model for unfractionated heparin dosing during cardiopulmonary bypass

High-dose heparin is used during cardiopulmonary bypass (CPB) to prevent thrombosis in the circuits used for extracorporeal circulation. The aim of this study was, initially, to develop a population pharmacokinetic/pharmacodynamic (PK/PD) model to assess the variability of PK/PD parameters and their correlation with the results of the routine haemostatic test activated clotting time (ACT) and thereafter to develop a Bayesian estimator enabling an individualized dosing strategy. Fifty consecutive patients undergoing cardiac surgery with CPB were included in the study. Heparin was administered as an initial bolus of 300 IU kg−1 followed by additional boluses of 5000 IU to maintain ACT