Vancomycin Sequestration in ST Filters: An In Vitro Study

Background. Sequestration of vancomycin in ST(®) filters used in continuous renal therapy is a pending question. Direct vancomycin-ST(®) interaction was assessed using the in vitro NeckEpur(®) technology. Method. ST150(®) filter and Prismaflex dialyzer, Baxter-Gambro, were used. Two modes were assessed in duplicate: (i) continuous diafiltration (CDF): 4 L/h, (ii) continuous dialysis (CD): 2.5 L/h post-filtration. Results. The mean initial vancomycin concentration in the central compartment (CC) was 51.4 +/− 5.0 mg/L. The mean percentage eliminated from the CC over 6 h was 91 +/− 4%. The mean clearances from the CC by CDF and CD were 2.8 and 1.9 L/h, respectively. The mean clearances assessed using cumulative effluents were 4.4 and 2.2 L/h, respectively. The mean percentages of the initial dose eliminated in the effluents from the CC by CDF and CD were 114 and 108% with no detectable sequestration of vancomycin in both modes of elimination. Discussion. Significant sequestration adds a clearance to that provided by CDF and CD. The study provides multiple evidence from the CC, the filter, and the effluents of the lack of an increase in total clearance in comparison with the flow rates without significant sequestration in the ST(®) filter comparing cumulative effluents to the initial dose in the CC. Conclusions. There is no evidence ST(®) filters directly sequestrate vancomycin.