Optimization of mid-dilution haemodiafiltration: technique and performance.
Luciano A Pedrini1, Annalisa Feliciani, Simona Zerbi
1Bolognini Hospital, Seriate, Bergamo, Italy. nefrologia.seriate@bolognini.bg.it
Summary
Reverse mid-dilution haemodiafiltration (MD-HDF) improves safety and middle molecule removal by optimizing filter configuration. This technique enhances convective-mixed dialysis efficiency while reducing risks associated with high pressures during treatment.
Area of Science:
- Nephrology
- Renal Replacement Therapy
- Dialysis Technology
Background:
- Mid-dilution haemodiafiltration (MD-HDF) is an efficient convective-mixed technique.
- Clinical application of MD-HDF faces challenges due to high pressures within the filter's blood compartment.
- This study aimed to optimize MD-HDF efficiency and mitigate associated risks.
Purpose of the Study:
- To evaluate the efficiency and safety of standard versus reverse configured MD-HDF.
- To assess solute removal, pressures, and hydraulic parameters during both configurations.
- To identify optimal conditions for MD-HDF application.
Main Methods:
- A randomized crossover study involving fifteen patients on renal replacement therapy (RRT).
- Patients underwent standard and reverse MD-HDF under identical operating conditions.
- Evaluated urea, phosphate, and beta2-microglobulin removal, dialysate clearances (K(DQ)), eKt/V, and monitored pressures on-line.
Main Results:
- Reverse MD-HDF maintained safe rheologic and hydraulic conditions, unlike standard MD-HDF which experienced excessive pressure.
- Reverse MD-HDF showed improved resistance index and membrane permeability, leading to significantly higher beta2-microglobulin removal.
- Urea removal was greater with standard MD-HDF, while phosphate removal was comparable between configurations.
Conclusions:
- MD-HDF effectively removes medium-sized uremic compounds and phosphate.
- Safe application of MD-HDF requires a reverse configuration of the dialyzer.
- The larger MD-220 dialyzer in reverse configuration offers better tolerance and middle molecule clearance, despite slightly reduced small molecule removal.
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