Hémodialyse : actualités et perspectives

Abstract

In all blood purification systems, as in the native kidneys, waste products are removed through a semi-permeable membrane. However, in contrast with the native kidneys, the solute transfer through the semi-permeable membrane is not necessarily a ‘convective transfer’ due to ultrafiltration. In conventional hemodialysis the transfer is mainly by diffusion, but the convective transfer can play an important role in particular hemodialysis procedures (hemofiltration,hemodiafiltration) requiring the infusion of a substitution fluid. In conventional hemodialysis, as in hemofiltration and hemodiafiltration, the qualitative and quantitative composition of dialysis and substitution fluids is usually similar to that of extracellular fluid. Newer dialysis procedures use dialysis and substitution fluids with a quantitatively non-physiologic composition. In acetate-free biofiltration, the dialysis fluid is base-free (without acetate or bicarbonate): the bicarbonate repletion of the patient is obtained by infusion of a solution containing sodium bicarbonate. In duo-cart biofiltration, the dialysis fluid contains only sodium chloride and bicarbonate: the ionic complement (potassium, calcium and magnesium chlorides) and glucose are infused in the extracorporeal blood line.