Lactate versus bicarbonate on-line hemofiltration: a comparative study.

In this study, 6 chronic anuric uremic patients underwent lactate hemofiltration (HF) with a substitution fluid, prepared in bags, for 3 months and bicarbonate HF, with continuous on-line preparation of the substitution fluid, for 3 months. We determined Na+, Cl-, K+, total calcium (Ca), ionized calcium (Ca2+), phosphate, intact parathormone (I-PTH), pH, PCO2, PO2, and HCO3- in plasma before, during, and after the treatment, as well as Ca, Ca2+, phosphate, and I-PTH in the ultrafiltrate. Moreover, heart rate (HR) and mean arterial pressure (MAP) were continually recorded during the procedure. Furthermore, the patients underwent echocardiographic study before and after the session. In comparison with lactate, bicarbonate HF caused a significant increase in HCO3- and a decrease in K+ plasma concentrations. This was detectable, with lower significance, even 44 h after the end of the treatment. At the end of the long interdialytic period (68 h after the end of the treatment), no significant difference was detectable. pH and PCO2 showed a significant but transient increase during HF. The other parameters investigated did not differ significantly between the two methods.