Hydrogen ion balance in dialysis therapy

A model to describe hydrogen ion balance (H+B) in acetate and bicarbonate dialysis therapy was developed based on measurement of metabolic addition of hydrogen ion (H+) to the body between and during dialyses and measurement of net buffer repletion during dialysis. Metabolic H+ generation was shown to be equal to 0.77 times the protein catabolic rate plus the total net removal of lactate and beta-hydroxybutyrate ions during dialysis. Buffer repletion was calculated from total net flux of acetate and bicarbonate during dialysis. The model was used for eight paired studies of H+B on one week each of acetate and bicarbonate dialysis and showed that cumulative H+B with acetate was -7 +/- 28 (M +/- SEM) mmol/week compared to -175 +/- 45 mmol/week with bicarbonate (P less than 0.001). It is concluded that there is an initial, strongly negative H+B when patients on acetate dialysis are converted to bicarbonate. The possible physiologic significance of this is discussed.