The effect of increasing blood flow rate and dialysate flow rate on dialysis adequacy in maintenance hemodialysis patients

Abstract

Objective A few publications show that increasing dialysate flow rate(Qd) no longer lead to an increase in Kt/V measurement with using high-flux membrane dialyzers. The aim of this study is to assess the effect of increasing dialysis flow rate or blood flow rate(Qb) during hemodialysis with low-flux membrane dialyzer on the adequacy of dialysis. Methods In this study, 54 patients with maintenance HD were assessed. All patients were dialysed with conventional bicarbonate heamodialysis and three sessions per week with each Qb(250 mL/min or 500 mL/min) and Qd (500 mL/min or 800 mL/min) were performed. Delivered dose of dialysis, measured by Kt/Vsp, was assessed during last dialysis session per week. Kt/Vsp was calculated according to the equations by Daugirdas. Blood samples were drawn immediately predialysis and postdialysis from the arterial of the access. HD parameters were acquired directly from the monitor display: effective blood flow rate, Qd, ultrafiltration volume and dialysis time. Results A total number of 46 patients including 30 males and 16 females were studied. The mean age of the studied population was (52.78±11.12) years and the mean dialysis duration was 1057 days. There was no statistical difference in ultrafiltration volumes per week. The relative gains in Kt/Vsp for increasing Qb from 250 to 300 mL/min and Qd from 500 to 800 mL/min was 8% and 4%, respectively. When Qd was 800 mL/min, we spent 2.2 L of acid concentrate and 72.76 L of water more than when Qd was 500 mL/min in only one patient per HD session. Conclusions Increasing Qb from 250 to 300 mL/min is associated with a more efficient increase in Kt/Vsp than increasing Qd and also less water consumption. Key words: Renal Dialysis; Renal Blood Flow, Effective; Dialysis Solutions