Introduction: Recent studies indicate that the survival benefit with post-dilution on line hemodiafiltration (OL-HDF-post) are achieved if the infusion volume (Vinf) is greater than 20L per session, a goal that is not easily achieved due to hemoconcentration problems. Today we have automated techniques to achieve higher performance minimizing the number of alarms as Ultracontrol® (Ultrac). The objective in the first part of study was to evaluate the UltraC performance (expressed as the filtration fraction (FF) and Vinf) and which problems it presents, and in the second part, to study its performance with four different dialyzers.
Material and methods: 1st period. Nine patients were transferred to OL-HDF-post with UltraC. The first 3 months on OL-HDF all sessions were recorded and compared with hemodialysis sessions in the previous month. 2nd part: 18 patients on chronic OL-HDF-post were dialyzed for a week with each of these dialyser: FX1000, FX800, Elisio210H and Polyflux210.
Results: 1st period: In 3 patients, problems associated with inappropriate pressures emerged. In 3 patients there were problems associated with inadequate PTM and Psist that resolved changing to pressure control. Mean values were: maximum Qb 441 (21) (range 350-490) ml/min, Vinf 26.3 (3.3) l/session, FF 30.6 (2.5)%, KT 59.9 (5) l/session. KT increase of 12% compared to HD. 2nd part: Polyflux210 required less UltraC withdrawals than the others. Different PTM or Psist were found and determined the need for removal of the system. The KT was adequate. a) The UltraC system reaches FF of 30% with minimal alarms and Vinf higher than 20 l. b) Structural characteristics of dialysers can limit their use with UltraC although they managed to desirable KT and Vinf in a manual way.