Online hemodiafiltration: a multipurpose therapy for improving quality of renal replacement therapy.

By combining diffusive and enhanced convective clearances, hemodiafiltration (HDF) offers the most efficient and biocompatible renal replacement therapy modality at the present time. HDF increases solute mass transfer and enlarges the molecular weight spectrum of uremic toxins, and reduces the microinflammation profile of dialysis patients. Online (ol) production of substitution fluid by 'cold sterilization' of dialysis fluid gives access to virtually an unlimited amount of sterile and non-pyrogenic solution. ol-HDF provides a multipurpose platform that permits to develop and customize HDF options (HDF, post-, pre-, mixed-, mid-dilution) to patients' needs. With these unique features, ol-HDF should be considered as a dialysis platform permitting to develop new options such as feedback-controlled volemia, automation of priming and restitution and daily treatment schedule. At the present time, ol-HDF offers major options to enhance dialysis efficacy and to improve global care of patients.