The purpose of this study is to detemine whether effect of Acetate-free solution on cardiac index and cardiac output measured by saline dilution techniques compares with Acetate-based solution in online-hemodiafiltration

Inclusion Criteria:

• End-stage renal disease patients with age over 20 years and stable clinical status
• Dialytic age > 6 months
• Maintenance hemodialysis with online-hemodiafiltration mode at King Chulalongkorn Memorial Hospital
• Use arteriovenous fistula or arteriovenous graft as vascular access for hemodialysis
• No vascular access recirculation
• No liver impairment
• No severe, intractable metabolic acidosis or alkalosis (HCO3 <15, >30)
• No pre-existing severe, intractable hypocalcemia (Ca < 7.5) or clinical of hypocalcemia

Exclusion Criteria:

• On hemodialysis via tunnel catheter
• Vascular access recirculation
• Liver dysfunction
• Severe, intractable metabolic acidosis or alkalosis (HCO3 <15, >30)
• Pre-existing severe, intractable hypocalcemia (Ca < 7.5) or clinical of hypocalcemia
• Acute or recent myocardial ischemia or congestive heart failure (within 1 months)
• Threatening arrhythmia (VT, VF, sustained SVT, AF with rapid ventricular response)
• Patients affected by acute or chronic infections, malignant tumor