Studies on circulatory stability during bicarbonate hemodialysis with constant dialysate sodium versus acetate hemodialysis with sequential dialysate sodium.

Eight stable patients on maintenance hemodialysis were studied while undergoing (a) acetate hemodialysis with a sequential dialysate sodium concentration from 147 to 137 mEq/L (SNa-HDA) and (b) bicarbonate hemodialysis with a constant dialysate sodium concentration of 140 mEq/L (HDB). Circulatory behavior was observed during both of these methods, and both were found to allow a high volume removal. However, as a consequence of the high sodium load during SNa-HDA, volume was shifted from the extra- to the intravascular space. This stabilizing effect on the circulation disappeared with the sequential decrease of dialysate sodium concentration (despite a constant plasma sodium concentration (despite a constant plasma sodium concentration of approximately 140 mEq/L), which was concomitant with a significant decline of the mean arterial blood pressure and an inadequate compensation of the metabolic acidosis. In contrast, a better circulatory response to comparable volume removal was found during HDB, expressed by a stable mean arterial blood pressure in the presence of well-balanced arterial acid-base values.