Lack of effect of extracorporeal membrane oxygenation on tigecycline pharmacokinetics

Sir, Extremely limited data are available on the pharmacokinetics of antimicrobial agents during extracorporeal membrane oxygenation (ECMO). We report the case of a young adult patient who was admitted on day 1 to our intensive care unit for acute respiratory failure due to intra-alveolar haemorrhage. Ventilator-acquired pneumonia due to Staphylococcus epidermidis and Staphylococcus warneri developed, initially treated with intravenous vancomycin. Despite maximal ventilator settings, optimal respiratory function could not be obtained, so veno-venous ECMO was started on day 38. The system comprised a membrane oxygenator (Quadrox Bioline, Jostra-Maquet, Orleans, France) and a centrifugal pump (Biomedicus 560, Medtronic, Minneapolis, MN, USA). Yet on day 50, respiratory conditions worsened. A persistent S. epidermidis pulmonary infection was observed, with induction of vancomycin resistance requiring antibiotic change to tigecycline on day 55. The patient's renal function remained stable during hospital stay (CLCR 95 mL/min), but despite therapy and complete bacteria eradication the patient's condition continued to deteriorate until death occurred on day 61. Tigecycline concentrations were measured by liquid chromatography–tandem mass spectrometry in plasma and tracheal aspirate.1 The Berkeley Madonna software (v 8.3.18, University of California, Berkeley, CA, USA) was used to predict tigecycline concentrations using population mean parameter estimates from a previously published pharmacokinetic study in critical care patients.2 The tigecycline dosing regimen and concentrations are presented in Table 1. Interestingly, concomitant tigecycline concentrations measured in plasma and aspirate were virtually identical. Plasma and tracheal aspirate concentrations of tigecycline administered intravenously at a dose of 50 mg twice daily simultaneously to ECMO Plasma and tracheal aspirate concentrations of tigecycline administered intravenously at a dose of 50 mg twice daily simultaneously to ECMO The potential effect of ECMO on tigecycline pharmacokinetics had never been investigated before. Tigecycline is characterized by a large volume of distribution with a population mean value of 398 L in critical care patients,2 which is therefore unlikely to be noticeably increased simply by dilution into the system, but adsorption on the circuit membranes could not be excluded.3,4 However, measured tigecycline plasma concentrations were virtually similar to the values predicted for a critically ill patient with CLCR = 95 mL/min and body surface area = 1.42 m2,2 suggesting that ECMO has no effect on tigecycline pharmacokinetics. Support was only provided by institutional sources. None to declare.