Hemodiafiltration

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Hemodiafiltration is a method of dialysis which combines hemodialysis and hemofiltration.

Hemofiltration is sometimes used in combination with hemodialysis, when it is termed hemodiafiltration, as a chronic treatment in some centers. By using large quantities of substitution fluids (60-90 liters per treatment) toxins and solutes can be removed from the patient, such as beta-2-microglobulin which is much more efficiently removed with hemofiltration than hemodialysis.

Hemodialysis is very efficient at removing low molecular weight toxins and hemofiltration is more efficient at the removal of higher molecular weight toxins; hemodiafiltration describes the combination of a hemofilter and a hemodialyser in the same circuit. This has been done by the addition of a dialysis membrane to a standard hemofiltration circuit in the ITU setting, and also by the addition of a hemofilter to a modified hemodialysis machine where the replacement fluid is generated by the machine during the dialysis session (on-line hemodiafiltration). More efficient removal of middle weight toxins by the additional hemofiltration might be expected to translate into better outcomes for dialysis patients receiving this treatment, however despite ongoing trials, no evidence of such a benefit has been shown.