Divert to ULTRA: differences in infused volumes and clearance in two on-line hemodiafiltration treatments.

Background:Mixed diffusive-convective dialysistherapies offer greater removal capabilities than conventional dialysis. The aim of this study was to compare two different on-line, post-dilution hemodiafiltration (HDF) treatments with regard to achieved convective volume and middle-molecule dialysisefficiency: standard volume control (sOL-HDF) and automated control of the transmembrane pressure (TMP) (UC-HDF).Methods:We enrolled 30 ESRD patients (55.9 ± 14.0 years, 20/10 M/F) in a randomized, prospective, crossover study. The patients received a 3-month period of sOL-HDF followed by UC-HDF for a further 3 months, or vice versa, using the same dialysismachine. In sOL-HDF, fixed exchange volumes were set according to a filtration fractiongreater than or equal to 25%. In UC-HDF therapy, the exchanged volume was driven by a biofeedbacksystem controlling the TMP and its set point in a double loop. Patients maintained their treatment time, dialyzer, blood flow rate, and anticoagulant regimen unchanged throug...