Dialysate Sodium Lowering Trial

This is a pilot randomized clinical trial in which hypertensive hemodialysis patients will be randomized to a low dialysate sodium (Na) of 135 mEq/L or a standard dialysate Na of 138 mEq/L. Patients will be randomized 2:1 to the low arm. Dialysate Na will be lowered 1 mEq/L every 2 weeks, as tolerated. Tolerance will be assessed by symptoms, intradialytic hypotension (IDH) episodes (systolic BP \<90 or intervention for symptoms or BP drop during dialysis), achievement of dry weight. The trial will last for 6 to 12 months, for an individual, depending on when they entered the trial. The primary outcome is feasibility and safety of using the lower dialysate sodium which is assessed by symptoms during or immediately after dialysis, intradialytic hypotension episodes and the frequency of emergency room visits and hospitalizations. Several secondary outcomes will be measured including blood pressure prior to dialysis and at home, change in plasma Na over time, dry weight, post-dialysis weight, interdialytic weight change, symptoms of thirst and dry mouth, self-reported dialysis recovery time, relative blood volume change during a single treatment (via 'Critline') and, in patients without an implanted electronic device, extraceullular fluid volume (via bioimpedance).