Altering Bicarbonate Delivery During Hemodialysis to Affect Filtration of Indoxyl Sulfate

Investigators will try to perform dialysis with a low bicarbonate bath which will leave patients blood pH (Hydrogen ion concentration) relatively unchanged then switch to a normal bicarbonate bath during the second half of dialysis so that they attain the pH (Hydrogen ion concentration) they normally would. Investigators will use these measurements to test test the hypothesis that Indoxyl Sulfate (IS) binds to proteins with greater affinity under basic conditions and further to test the hypothesis that it is possible to remove a greater amount of Indoxyl Sulfate (IS) when patients are maintained relatively acidotic during dialysis for a longer period of time due to the greater availability of free IS that can pass through the dialyzer.