Intraerythrocytic pH variations during hemodialysis: A 31P NMR study

Intraerythrocytic pH variations during hemodialysis: A 31 P NMR study. Before hemodialysis, patients have an intraerythrocytic pH (pH i ) and an extracellular pH, measured in whole blood (pH o ), which are lower than those of healthy controls. During bicarbonate hemodialysis, pH i values continuously increase, approaching a normal value at the end of the session. Concomitantly, pH o values follow similar variations. During acetate hemodialysis, pH i values exhibit a steep initial decrease, reaching a minimum after about 15 minutes. Concurrently, however, pH o values decrease only slightly. This phenomenon seems to originate in the intraerythrocytic medium and might be due to a shift in intracellular CO 2 /bicarbonate equilibrium. This drop in pH i exhibits interpatient variability, suggesting that the magnitude of pH decrease would be correlated with the degree of the problems observed in some patients undergoing acetate hemodialysis.