[Acetate-free on-line PHF: how to improve hyperacetatemia and haemodynamic tolerance]

The small quantity of acetate present in the dialysis fluid exposes patient's blood to an acetate concentration 30-40 times the physiological levels. This amount is even greater in hemodiafiltration on-line. Our purpose was to evaluate the clinical-analytical effects using three different dialysis techniques in the same patient.

35 patients on hemodialysis were included. All patients were treated with conventional bicarbonate dialysate for 3 months, after randomization were switched to first be treated with PHF online with standard bicarbonate dialysate for 6 months and then switched to PHF on-line acetate-free dialysate for the other 6 months or to invert the two last periods. Blood samples were drawn monthly throughout the study and clinical data were obtained.

Postdialysis blood acetate levels were higher in patients treated with conventional bicarbonate dialysate with respect to the period of PHF with free-acetate dialysate. Moreover, the percentage of patients with postdialysis blood acetate levels in the pathologic range was higher in patients treated with conventional bicarbonate dialysate respect to PHF on-line acetate-free dialysate period (61% vs. 30%). Serum concentrations of chloride postdialysis were higher and serum concentrations of bicarbonate pre and posthemodialysis were lower in the PHF free-acetate period. The incidence of hypotensive episodes was significantly lower in the PHF on-line with conventional dialysate.

PHF on-line with free-acetate dialysate allows that most of patients finished hemodialysis with blood acetate levels in the physiologic ranges. PHF on-line is a predilutional hemodiafiltration treatment with better tolerance than hemodialysis with standard bicarbonate dialysate.