Dialysate composition - Buffering

Bicarbonate dialysate is now the fluid of choice. Bicarbonate is the primary buffer that traditionally has been prescribed in the range of 33-38 mmol/l. The concentration of acetate used is variable and contributes to the total buffering, with a range of 4-8 mmol/l, whereas 5-6 mmol/l is most widely used and appears to be safe, providing these sources of bicarbonate concentration are considered when the dialysate prescription is written. The aim of intradialytic buffering is to avoid post dialysis alkalosis and acidosis before the next session. Net acidosis may lead a catabolic state, insulin resistance and bone loss. Net alkalosis may lead  to reduced cerebral flow, cramps and fatigue.  Recent observational data have demonstrated that high dialysate bicarbonate (>35 mmol/l) may be associated with the adverse outcomes. Modeling dialysate bicarbonate is of uncertain benefit, but lower bicarbonate may assist patients with intradialytic hypotension.