Electrolyte modelling in haemodialysis--potassium

Abstract

Cardiovascular tolerance to haemodialysis is reduced by the appearance of cardiac arrhythmias whose onset is partly caused by an intradialytic increase in cell membrane polarisation. This is due to the current method of dialytic potassium removal based on the use of dialysis baths with a fixed potassium content (constant KD), which leads to a dialytic transmembrane concentration gradient that decreases during the course of dialysis. By varying the potassium concentration in the bath (variable KD) during dialysis, it is possible to obtain a constant dialytic transmembrane concentration gradient. For this study, we selected 36 haemodialysis patients attending 17 dialysis centres in whom Holter monitoring revealed the presence of premature ventricular complexes (PVCs) that increased in number during dialysis. In order to compare the arrhythmogenic effect of the treatments, the patients were randomised to undergo dialysis with a constant or variable potassium concentration according to a cross-over design. The main variable, ln(PVC/h + 1)post-ln(PVC/h + 1)pre = patient effect+direct treatment effect+carry-over effect, was statistically analysed using the analysis of variance. The results show that dialysis carried out using variable potassium concentrations significantly reduced the arrhythmogenic effect of standard dialysis.