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.

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.

The influences of dialysate bicarbonate concentrations on hemodialysis patients