Hyperhydration, the sum of persistent (PH) and intermittent (IH) ones is the strong predictor of mortality in patients on program haemodialysis (PHD). The aim of this research was to investigate the complex of methods for minimization of PH as well as IH. Materials and methods. The bioimpedance multifrequency analysis (BIA), relative blood volume (RBV) monitoring and plasma conductivity evaluation by ionic dialysance device were performed in candidates for kidney transplantation. Results. In 380 PHD patients, comparing with 26 healthy persons the expansion of extracellular volume was only observed even in the cases of the huge (3.5–15 L) overload. PH of more than 15% of extracellular volume was observed in 41% of patients. The deviation of hydration status from reference value was 3.7 ± 1.4 L at first measurement and 1.9 ± 1.2 L at last one in every patient. RBV decreased insignificantly (less than 2.5% / L ultrafiltration) during PHD sessions in patients with PH. This value increased after dry weight consummation and it appeared as surrogate of intravascular refueling capacity. The minimization of sodium dialysate – plasma gradient resulted in decrease of IH. Conclusion. The elimination of both PH and IH in PHD patients is the paramount goal; it demands the complex approaches and further investigations.

The experience of the introduction of convective methods since the eighties of the 20th century is described. Aim: to evaluate the influence of convective transport supplementation on renal replacement therapy results. Methods and results. The number of convective procedures was applied: hemodiafiltration with commercial substituted fluid, paired filtration dialysis, acetate-free biofiltration, original hybrid methods, online hemodiafiltration. The main trend was the magnification of substituted volume. In the long run after switching from conventional dialysis to convective therapy the increase of Kt/V, the decline of phosphate, the rise of serum albumin, the decrease of CRP level and ESA consumption, QOL improvement and the drop in severity of intradialysis complications were observed. Over last six years online hemodiafiltration has become the standard of dialysis therapy in our Center. Conclusion. The undoubted advantages of convective modalities and accessibility of online hemodiafi ltration make these methods the gold standard of dialysis therapy.