there are varius kinds of hemodialysis machine . in profile setting of bicarbonate we have varius grading of bicarbonate profile .

for example in fersenius machine there is +8 to -8 variation of bicarbonate . in this machine we started to give more bicarbonate to patients who have bicarbonate level below 22 .

Reasonable for intradialytic hypotension. 

intradialytic bicarbonate gain is congruent with bath-serum HCO3 difference. As a matter of fact if patient has low or very low serum HCO3 the gain from dialysate is large with HCO3  setted to 35.  If you set HCO3 over 35 the gain is faster and pH quickly arises so you could induce arrhythmias and hypotension

 .

,

In my opinion the usefulness of HCO3 profiling is the following:

start dialysis with LOW HCO3 bath and gradually increase it. This allows bath-serum HCO3 difference narrowed along all dialysis treatment, avoiding abrupt pH increase. However HCO3 gain prolongs in the last part of dialysis