RESUMEN
On-line hemodiafiltration is a technique that relies on the re-injection of pyrogen-free substitution fluid obtained by cold filtration of dialysate. Therefore, safety of this treatment modality depends on the quality of dialysate and, mainly, on the integrity of the ultrafilter(s) employed. Double-chamber on-line hemodiafiltration is a new technique where re-infusion takes place inside the dialyser by means of dialysate backfiltration. The peculiar geometry of the dialyser allows intra-treatment assessment of its fibre integrity. In this paper, we tested feasibility and safety of this new modality of on-line treatment. The extracorporeal blood and infusate pressure values resulted well inside the safety range. Blood urea clearances and beta(2) removal were consistent with the figures usually found in standard hemodiafiltration. Whole blood production of cytokines was similar when blood was exposed to saline or infusate, both values being comparable to the spontaneous whole blood cytokine release. The on-line dialyser fibre integrity check showed a great sensitivity even for minimal dialyser damage. We conclude that double-chamber on-line hemodiafiltration is a feasible and safe procedure. Our preliminary results encourage the undertaking of multicentre, prospective, randomised studies.