• Intradialytic BP change
  

• Intradialytic changes in cardiac output and peripheral vascular resistance
  
• Interdialytic weight gain change
  
• Thirst scores
  

Hypertension and intradialytic hypotension are common complications in patients on chronic maintenance hemodialysis (HD). Sodium balance is important in mediating both processes. Recent evidence shows that individualization of the sodium concentration in the dialysate to match the patient's own serum sodium results in less thirst, less interdialytic weight gain, less HD-related symptoms, and better blood pressure control. In this project we plan to evaluate the safety and tolerability of sodium individualization in hypotension-prone patients in order to generate pilot data for a larger study in patients with intradialytic hypotension. In this protocol, we will recruit 7 hypotension-prone subjects. We will use an open-label cross-over design with randomized blocks. After a 3-week baseline period where pre-HD serum sodium will be measured weekly to establish each patient's average serum sodium, subjects will be randomized to 2 weeks on standard dialysate sodium (140 mmol/L) or individualized dialysate sodium (same concentration as the average pre-HD serum sodium during the baseline period), then crossed over to the other for another 2 weeks (total study period 7 weeks, 2 weeks baseline, 4 weeks intervention). The remainder of the dialysis prescription, prescribed dry weight and vasoactive drugs will remain unchanged throughout the study. Clinical information, pre/intra/post-HD blood pressure and hemodynamics (cardiac output and systemic vascular resistance), and the frequency and severity of intradialytic symptoms related to hypotension will be collected on HD sessions during the 4 weeks of intervention.