Population Pharmacokinetics and Dosing Optimization of Piperacillin-Tazobactam in Critically Ill Patients on Extracorporeal Membrane Oxygenation and the Influence of Concomitant Renal Replacement Therapy

Critical illness and extracorporeal circulation, such as extracorporeal membrane oxygenation (ECMO) and continuous renal replacement therapy (CRRT), may alter the pharmacokinetics of piperacillin-tazobactam. We aimed to develop a population pharmacokinetic model of piperacillin-tazobactam in critically ill patients during ECMO or CRRT and investigate the optimal dosage regimen needed to achieve ≥90% of patients attaining the piperacillin pharmacodynamic target of 100% of dosage time above MIC of 16 mg/L. This prospective observational study included 26 ECMO patients, of which 13 patients received continuous venovenous hemodiafiltration (CVVHDF). A population pharmacokinetic model was developed using nonlinear mixed-effects models, and Monte Carlo simulations were performed to evaluate creatinine clearance (CrCL) and infusion method in relation to the probability of target attainment (PTA) in four patient groups according to combination of ECMO and CVVHDF. A total of 244 plasma samples were collected. In a two-compartment model, clearance decreased during ECMO and CVVHDF contributed to an increase in the volume of distribution. The range of PTA reduction as CrCL increased was greater in the order of intermittent bolus, extended infusion, and continuous infusion method. Continuous infusion should be considered in critically ill patients with CrCL of ≥60 mL/min, and at least 12, 16, and 20 g/day was required for CrCL of