Pascal Kopperschmidt

High-Volume Postdilution Hemodiafiltration Is a Feasible Option in Routine Clinical Practice

Hemodiafiltration (HDF) with 20–22 L of substitution fluid is increasingly recognized as associated with significant benefits regarding patient outcome. However, some doubt exists as to whether these high volumes can be achieved in routine clinical practice. A total of 4176 sessions with 366 patients on postdilution HDF were analyzed in this 1-month observational cohort study with prospective data collection. All dialysis machines were equipped with AutoSub plus signal analysis software that automatically and continuously adapts the substitution fluid flow according to the blood flow, blood viscosity, and dialyzer characteristics. Percentages of sessions with different types of vascular access were compared regarding achievement of ≥21 L substitution fluid. Logistic regression analysis was conducted to study the independent relationship of selected variables with achievement of ≥21 L substitution volume. Patient- and dialysis-related variables that showed an association with the convection volume were entered in a multivariable model that included hematocrit up front. Respectively, 87%, 84%, and 33% of routine sessions conducted with fistulas, grafts, and catheters qualified as high-volume HDF. Serum albumin levels ≥4.2 g/dL were positively associated with the achievement of at least 21 L substitution volume. Positive associations were also observed for blood flows in the ranges 350–399 and ≥400 mL/min compared with the reference range (300–350 mL/min), for longer treatment time, for fistula versus catheter, for higher filtration fraction, and for dialysis conducted at the end of the week versus Monday. It can be concluded that implementation and sustainability of high-volume HDF is possible in routine clinical practice for almost all patients treated with fistulas and grafts.

Modifiable factors associated with achievement of high-volume post-dilution hemodiafiltration: results from an international study.

Background The aim was to investigate factors associated with the successful achievement of ≥21 l/session of substitution fluid volume in patients on post-dilution hemodiafiltration. Methods 3315 patients treated in 6 European countries with the Fresenius 5008 CorDiax machine including the AutoSub Plus feature were considered. Variables that showed a relationship with convection volume were entered in a multivariable logistic regression model. Results Mean blood flow was 379 ± 68 ml/min. Median substitution volume was 24.7 L (IQR 22.0–27.4 L). Mean filtration fraction was 28.3 ± 4.1%. 81.5% of sessions qualified as high-volume HDF (substitution volumes ≥21 L). Higher age, dialyzer surface area, blood flow and treatment time were positively associated with the achievement of ≥21 L substitution volume; higher body mass index, male gender, higher hematocrit, graft or catheter vs. fistula, and start of week vs. mid-week were negatively associated. Conclusions Dialysis center policy in terms of blood flow, treatment time, filter size, and perhaps even hemoglobin targets plays a key role in achieving high-volume HDF. All of these are modifiable factors that can help in prescribing an optimal combination of dialyzer size, achievable blood flows, and treatment times.

Online Hemodiafiltration by Fresenius Medical Care

Hemodiafiltration has been identified by Fresenius Medical Care (FMC) as a vital need to improve care and outcome of chronic kidney disease patients. By enhancing the removal of middle molecular uremic toxins and improving hemodynamic and global tolerance of dialysis sessions, HDF was recognized as an efficient dialysis modality and a mean to improve patient treatment perception and reduce disease burden. By providing fluid substitution online, HDF appeared the only economically and technically long-term viable solution. Online HDF therapy has been a major R&D focus for FMC over the last decades leading to the development of several online HDF machines with different features.