Effects of chronic biofiltration with PAN membranes on acid-base status: polycentric study

Effects of chronic biofiltration (BF) with PAN membranes on acid-base status (ABS): polycentric study. From the 39 cases in a polycentric study we selected 13 patients with metabolic acidosis (pH 7.23 +/- 0.03), marked reduction of plasma bicarbonate (15.4 +/- 2.2 mEq/l) and hyperkalemia (6.2 +/- 0.6 mEq/l). BF was performed with a continuous post-dilutional supply of HCO3 (85 mmol/h), and attained rapid normalisation of blood bicarbonates and serum potassium during the treatment. After 6 months of BF treatment the pre-dialytic ABS showed remarkable improvement, and values were normal after one year. The remaining 26 patients in the polycentric study, treated by chronic BF without severe acidosis, showed good dialytic tolerance. In 15 of them the supply of bicarbonate was too high (because of moderate post-BF alkalosis) and we had to reduce the buffer inflow to about 50 mmol/h.