Haemodialysis dose, extracellular volume control and arterial hypertension.

Patients with chronic renal failure on periodical dialysis frequently are hypertensive. This frequency has increased in relation to the liberalization of diet and to short dialysis with a high sodium concentration in the dialysate. Although various factors influence the pathogenesis of this type of hypertension, volume overload is the most significant. The achievement of an optimal dry weight is still one of the most difficult and important tasks of a dialysis clinic. The reduction in extracellular volume in haemodialysis implies an improvement in dialysis tolerance. The time factor is one of the principal elements in this control, but it is possible, using other elements, to improve tolerance in 4-5 h sessions and to achieve the proper dry weight associated with normotension in most patients.