Studies of bicarbonate dialysate and effects of acetate in hemodialysis

Bicarbonate ion is not stable in the neutral dialysate and forms complex salt in presence of calcium and magnesium ions. We have prescribed bicarbonate containing dialysate (bicarbonata dialysate) and developed the bicarbonate dialysate central supply system. This bicarbonate dialysate contains about 3mmol/l acetic acid and 6mmol/l sodium acetate to stabilize pH and Pco₂. Estimation of the stability of bicarbonate dialysate on the central supply system was examined and comparative studies between hemodialysis with acetate containing dialysate (Ac-D) and with bicarbonate dialysate (Bc-D) were performed in 74 patients. Thirty one patients were studied to compare the clinical data and the incidence of morbidity between Ac-D and Bc-D. In 56 patients, the double blind-cross over tests were carried out between Ac-D and Bc-D. The rate of acetate transfered from dialysate to blood was estimated in 21 patients.<br>Results were followed as: 1) pH and Pco₂ of the bicarbonate dialysate were adjusted and kept optimal values. Accordingly, concentration of soluble calcium in the bicarbonate dialysate were stabilized. 2) The improvements of clinical data and abating of morbidity during hemodialysis were obtained when Ac-D was changed to Bc-D. 3) In the double blind-cross over tests, additional symptoms were developed in 34 patients (61%) and 12 patients (21%) were not able to continue the hemodialysis owing to their severe symptoms when Bc-D was substituted by Ac-D. 4) The rate of transfered acetate was calculated at 0.41mmol/hr/kg (mean) on Bc-D and 3.47mmol/hr/kg (mean) on Ac-D when HFAK-1.1m² was used. A small amount of acetate contained in the bicarbonate dialysate (9mmol/l) was utilized completely with no increase of serum acetate level or symptoms. 5) There were no side effects found during 32 months's maintenance Bc-D.<br>It is possible from these data that the high rate of transfered acetate is one of causes inducing morbidity during Ac-D, and that less morbidity of Bc-D leads to more efficient hemodialysis resulted in improvements of clinical data. According to our statistics, about 20% of whole hemodialysis patients are intolerance to Ac-D and about 60% of them are necessary of Bc-D to maintain with no symptoms during hemodialysis.<br>Bc-D should be a choice when short time dialysis are tried with high performance dialyzer.