In advanced countries haemodialysis treatment is available to all patients with chronic renal failure who need it. At present nephrologists must resolve the problem when it is possible to withold long-term haemodialysis treatment, or withdraw it because it no longer leads to prolongation of a good quality life. The results of long-term dialysis treatment depend on the correct timing of its initiation and the quality of nephrological care provided already a long time before the development of renal failure. The morbidity, mortality and quality of life of the patients are influenced in a fundamental way by the quality of provided haemodialysis. An important factor is the dose of dialysis treatment evaluated according to index Kt/Vurea reflecting the urea elimination and obviously also the elimination of other low molecular weight substances. Although prospective controlled trials did not prove so far a favourable effect of haemodialysis membranes permeable for larger molecules ("high-flux" membranes) on the patients´ fate, the possible toxic effect of so-called middle molecule substances and peptides with a low molecular weight is assumed. Data suggesting improvement of the quality of life of patients having daily haemodialyses call for further investigations. A still unresolved problem of contemporary haemodialysis systems remains inadequate biocompatibility which leads to reactions associated with possible acute and long-term damage of dialyzed patients.

        Key words: Haemodialysis - Effectiveness - Urea - Middle molecules - Dialysis membranes - Biocompatibility