[Hemodiafiltration with endogenous reinfusion (HFR): evolution of the method].

During hemodiafiltration (HDF) the increase in the ultrafiltration (uf) rate improves solute convective clearance. Therefore, considerable amounts of reinfusion liquid are necessary, whose quality must be guaranteed. The use of bags or bottles manufactured by industry causes many problems concerning handling (storage, repeated connections) and costs, and last but not least, it exposes the circuits to a contamination risk. Therefore, the technological research into on-line production systems of sterile and ultrapure reinfusion solutions is justified. The increasing interest in the on-line production of reinfusion fluids from the dialysing solution dates back to the 1990s, and the data in the literature are statistically positive concerning the improvement in depurative performances connected to the uf increase. Although, to be objective, a problem still exists, in real-time the absolute guarantee of the sterility and apirogenicity of the solutions produced on-line is impossible. Using a two-chamber filter, it is possible to produce reinfusion fluid from the uf of the patient himself, which has been 'regenerated' by a sorbent bed, in a closed circuit. This action eliminates any sterility problems, whilst, in addition, providing the possibility for good substance reinfusion such bicarbonates and essential and branched-chain aminoacids. This HDF method, hemo-filtrate-reinfusion (HFR), has clinically demonstrated, beyond its ease of execution, a reduction in physiological component loss, a high biocompatibility and an overall action in contrast to MIA syndrome factors, i.e. malnutrition, inflammation and atherosclerosis.