In vitro assessment of cefepime adsorption in filters used during renal replacement therapy.

Introduction: Renal replacement therapy efficiently eliminates cefepime. A published in vitro study concluded to minimal adsorption of cefepime in a polysulfone derived filter. We aimed at assessing cefepime adsorption in filters used in critically ill patients.

Methods: Two filters were used, ST™150 and AV™1000. Adsorption was assessed in two modes, including diafiltration and filtration set to flow rates of from 2.5 to 1 L/h, respectively. Routes of elimination were assessed using NeckEpur^® method for 6-h session duration.

Results: The mean initial concentration in the 5-L central compartment (CC) in the 10 sessions was 47.7 ± 2.9 mg/L. Using the diafiltration mode, the mean adsorption rates in the ST™150 and AV™1000 were 1.3 ± 2.3% and 19.7 ± 1.2% (n = 3), respectively. Using the filtration mode at 1 L/h, the mean adsorption rates in the ST™150 and AV™1000 were 1.7% (n = 2) and 18.5% (n = 2), respectively.

Conclusion: ST™150 filter sequestrated very limited quantities of cefepime. In the diafiltration and filtration modes, AV™1000 sequestered cefepime at about 19%. The adsorption rate seems independent of the flow rate. Further studies would be needed to assess, in particular, the clinical relevance of these results in adults as well as drug adsorption in the pediatric population.