Effect of varying dialysate bicarbonate concentration on serum phosphate

Hyperphosphatemia is practically a universal problem in patients with chronic renal failure. Conventional treatment of hyperphosphatemia in this situation is either only partially effective or may be associated with potentially serious adverse effects. The authors examined the effect of inducing a metabolic alkalosis on serum phosphate in chronic hemodialysis patients by increasing the concentration of bicarbonate in dialysate. Seven patients participated in the study. Each patient was on dialysis for 2 weeks with each of 2 dialysate regimens. Regimen A contained a bicarbonate concentration of 25 mEq/L and Regimen B a bicarbonate concentration of 40 mEq/L. Despite Regimen B resulting in a significant increase in predialysis and postdialysis serum bicarbonate concentration and arterial pH, no significant difference in serum phosphate was demonstrated after 2 weeks of therapy.