Haemodiafiltration

Overview

Haemodiafiltration (HDF) is renal replacement therapy. It is a method of blood clearance based on the principleof diffuse and convection transport of substances through a semipermeable membrane. The method uses high-fluxmembranes, usually synthetic ones with a high ultrafiltration coefficient. According to the principle of preparationof a substitution solution HDF is divided into bag methods (substitution solutions in bags), on-line HDF (continualpreparation of substitution solution in an apparatus in the course of the procedure) and HDF based on reversedfiltration of the dialyzation solution through the membrane of the haemodiafilter. Depending on the length andfrequency of the procedure, there is intermittent HDF used in particular in the treatment of chronic renal failure andcontinual HDF used in acute conditions where renal failure is part of multiorgan dysfunction. Depending on the siteof administration of the substitution solution, we differentiate between predilution HDF (the substitution solutionis administered into the blood stream before haemodiafiltration) and postdilution HDF (the substitution solution isadministered into the bloodstream after the haemodiafilter). HDF methods are highly effective in the elimination oflow-molecular and medium-molecular substances. They are effective and well tolerated by patients. They can beused under conditions when standard haemodialysis is associated with circulatory instability or is not sufficientlyeffective. The author describes principles and possibilities of application of different modifications of HDF methods.

Key words:
renal replacement therapy, haemodiafiltration, chronic renal failure, solutions for haemodiafiltration,indications for haemodiafiltration