Acetate in hemodialysis solutions exerts inflammatory, vasodilatatory and cardio-depressive effects. Citrate has been proposed as an optimal substitute. The aim of the present trial was the comparison of the hemodynamic and biological parameters on a group of patients dialysed consecutively with 4 acetate-free haemodialysis techniques.

In a prospective crossover manner, we measured the hemodynamic and biological effects of four acetate-free hemodialysis methods: he acetate-free biofiltration with variable potassium (AFBK) and three methods with a citrate buffer: onventional hemodialysis (HD), on-line hemodiafiltration (HDF) and on-line hemofiltration (HF). Fourteen chronic hemodialysis patients (9 males mean age 72.21±11.21 years old) underwent 6 four-hour dialysis sessions for 2 weeks on each of the 4 studied techniques.

The AFBK technique presented less intradialytic hypotensive episodes (1 in 84 sessions) compared to the other techniques (HD: 29/84, HDF 22/82 and HF: 14/78; P<0.001). The blood pressure after one, two, three hours of dialysis and at the end of the hemodialysis session was significantly higher in the AFBK technique. On AFBK the net ultrafiltration (UF) (P<0.001) and the UF as a percentage of the dry weight (P=0.005) were significantly higher. A significant correlation between the prevalence of hypotensive episodes and the change of serum potassium levels (P=0.002) during the first hour of dialysis was detected.

AFBK is associated with a better intradialytic hemodynamic tolerance and could be an optimal method for frail hypotension-prone hemodialysis patients.