The Influences of Dialysate Bicarbonate Concentrations on Hemodialysis Patients

Background: Patients with decreased kidney function are in the positive acid balance due to insufficient renal acid excretion. To correct the varying degrees of metabolic acidosis in these HD patients, a high concentration of HCO3 in the dialysate is routinely used. During every 3-to-4 hours of HD treatment, a massive surge of HCO3 would enter the circulation and typically overcorrects predialysis acidosis to alkalosis and alkalemia. The sharp acid-base shift can cause some adverse consequences. The investigators believe that the rapid correction (or overcorrection) from the pre-dialysis metabolic acidosis to post-dialysis metabolic alkalosis during the 3-to-4 hours HD treatment would relate to adverse effects on HD patients. Thus the investigators conduct this study to prove the hypothesis that "prevention of post-dialysis alkalosis by using lower dialysate HCO3 concentration might cause less adverse outcomes in ESRD patients on HD." Study design: Prospective cross-over case-control study. Study population: A total of 60 patients who receive regular hemodialysis (three times per week) for more than 6 months in the regional teaching hospital.

In this group, the participants will receive "intervention" for 2 months first, followed by a wash-out period of 1 month and "control" for 2 months. In the "intervention period," the investigators will provide the participants with lower dialysate HCO3 concentrations. (dialysate HCO3 to 28 mmol/L for half of the HD session and 30 to the second half of their HD session.) Besides, the investigators will give the participants with pre-HD HCO3<22 mEq/L oral Na-bicarbonate 650 mg 1#-2# three times a day as supplements. In the "control period," the investigators will provide the participants with dialysate HCO3 concentration of 38-40 mEq/L (as we usually provide to patients).

In this group, the participants will receive "control" for 2 months first, followed by a wash-out period of 1 month and "intervention" for 2 months. In the "control period," the investigators will provide the participants with dialysate HCO3 concentration of 38-40 mEq/L (as we usually provide to patients). In the "intervention period," the investigators will provide the participants with lower dialysate HCO3 concentrations. (dialysate HCO3 to 28 mmol/L for half of the HD session and 30 to the second half of their HD session.) Besides, the investigators will give the participants with pre-HD HCO3<22 mEq/L oral Na-bicarbonate 650 mg 1#-2# three times a day as supplements.

Inclusion Criteria: adult uremic patients who received hemodialysis thrice weekly Exclusion Criteria: Hospitalized patients Patients newly initiated on HD (<6 months) Patients with HD access problems Patients recently discharged from the hospital (within one month). Patients on chemotherapy for cancer. Patients with a kidney transplant. Patients on steroids or other immunosuppressive therapy. Patients with recent surgery (within one month) Patients with an active bacterial infection. Patients with decompensated cirrhosis.