On-line hemodiafiltration

Abstract

On-line hemodiafiltration Hemodiafiltration was conceived in the 1970s as a therapy that combined the superior small molecule clearance of hemodialysis with the superior large molecule clearance of hemofiltration. Initially, widespread implementation of hemodiafiltration was slowed by technical and cost considerations related to the need for large volumes of substitution fluid. These problems have now been overcome by the development of on-line fluid preparation systems. On-line hemodiafiltration provides better removal of both small and large molecules compared to high-flux hemodialysis, providing filtration volumes of 20 liters, or more, are used. However, the increased efficiency appears to have limited impact on the total body burden of some higher molecular weight solutes, such as β2- microglobulin. This finding suggests that rates of intra-body mass transfer may limit the removal of at least some large molecules with highly efficient therapies. Also, it is not clear yet if the increased clearances associated with hemodiafiltration will lead to better patient outcomes in the long term.