Pharmacokinetics of Total and Unbound Cefazolin during Veno-Arterial Extracorporeal Membrane Oxygenation: A Case Report

Extra-corporeal membrane oxygenation (ECMO) therapy could affect effective drug concentrations via adsorption onto the oxygenator or associated circuit. We describe a case of a 25-year-old female who required a veno-arterial ECMO therapy for refractory cardiac arrest due to massive pulmonary embolism. She had mild renal dysfunction as a result of the cardiac arrest. A total of 2 g of intravenous cefazolin 8-hourly was administered. Pre- and post-oxygenator blood samples were collected at 0, 1, 4, and 8 h post antibiotic administration. Samples were analyzed for total and unbound cefazolin concentrations. Protein binding was ∼60%. Clearance was reduced due to impaired renal function. The pharmacokinetics of cefazolin appear to not be affected by ECMO therapy and dosing adjustment may not be required.