The authors made 41 haemodialyses in 21 patients in the course of a long-term dialyzation programme, using a dialyzation monitor connected with a computer. The aim of the investigation was to achieve at the end of the six-hour haemodialysis the optimal serum sodium value of 142 mmol/l, using different ultrafiltrations (1000, 2000 and 3000 ml/6 hours). It was revealed that to obtain the optimal serum sodium level it was necessary to use in the dialyzation solution a sodium concentration of 144.9 +/- 0.2 mmol/l. The water transport from the intracellular to the extracellular fluid was typical for the distribution of total body water, regardless of the volume of ultrafiltration. The amount of removed sodium during haemodialysis depended on the sodium concentration in the dialyzation fluid and on the ultrafiltration volume. The values of the volume and clearance of sodium-free water depended on the amount of sodium eliminated into the dialyzation solution.

Keywords: Female; Humans; Kidney Failure, Chronic /blood/; Male; Middle Aged; Numerical Analysis, Computer-Assisted; Renal Dialysis /methods/; Sodium /blood/