Pharmacokinetics of vancomycin in patients with multiple organ failure during continuous hemodiafiltration

Background. Some pharmacokinetic data for vancomycin (VCM) during continuous arteriovenous hemofiltration have been reported, but reports on the effect of continuous venovenous hemodiafiltration (CVVHDF), which is more commonly performed in patients with multiple organ failure (MOF), on VCM pharmacokinetics are scanty. Method. We selected five patients with MOF with serious infection with methicillin-resistant Staphylococcus aureus who needed treatment with VCM during CVVHDF. Blood flow rate was 80 ml/min, and dialysis fluid flow rate and filtration flow rate were both 0.5 l/h. A hemofilter made of polysulfon was used. After administration of 0.5–1.0 g of VCM, serial samples of blood and dialysate/filtrate outflow were obtained during CVVHDF. Pharmacokinetic parameters were calculated by a standard model-independent method. Results. Mean ± SE values for the pharmacokinetic parameters of VCM were: elimination rate constant, 0.0369 ± 0.0124/h; systemic clearance, 25.6 ± 5.0 ml/min; CVVHDF clearance, 15.9 ± 3.4 ml/min; non-CVVHDF clearance, 9.6 ± 8.4 ml/min; and distribution volume, 51.1 ± 21.6 l. The harmonic mean of half-life was 18.9 h. Conclusion. The systemic clearance of VCM during CVVHDF was relatively higher than anticipated. The pharmacokinetic parameters obtained in the present study will be useful to optimize the dose schedule of VCM in patients with MOF being treated with CVVHDF.