Quantification of Hemodialysis Dose: What Kt/V to Choose?

Abstract

Background

Quantification of hemodialysis became more accurate and easier after the advent of ionic dialysance and the use of methods for estimating urea distribution volume (V). The aim of this study was to compare different methods of hemodialysis dose assessment: Kt/V_Dau (Daugirdas 2^nd generation), Kt/V_OCM (Kt by OCM (Online Clearance Monitor) and V by Watson), and Kt/V_BCM (Kt by OCM and V by bio-impedance); and to assess the dialysis adequacy, defined by a Kt/V≥1.4.

Design

Prospective, observational study.

Methods

35 hemodialysis sessions were evaluated in 35 chronic hemodialysis patients. During each session, we measured simultaneously, Kt/V_OCM, Kt/V_BCM and calculated Kt/V_Dau by performing blood samples before and after each session.

Results

35 patients, gender (M/F: 19/16), mean age of 50.49 years, were evaluated. We noted a difference between the three methods of evaluating Kt/V index: Kt/V_Dau, Kt/V_OCM and Kt/V_BCM (1.82 ± 0.29; 1.45 ± 0.23; 1.8 ± 0.33, p<0.001). Comparison of Kt/V_OCM with Kt/V_Dau and Kt/V_BCM leads to a significant systematic underestimate of Kt/V by 22% and 20.5% respectively. Better agreement between Kt/V_Dau and Kt/V_BCM was observed. The adequate hemodialysis was achieved, according to three methods: Kt/V_Dau, Kt/V_OCM and Kt/V_BCM respectively in 100%, 57,1% and 88.6% of the cases.

Conclusions

The Kt/V index is different depending on the method used for its evaluation. The three methods can be used for quantification of hemodialysis with a better agreement between Kt/V_Dau and Kt/V_BCM. In this study, Kt/V_OCM results underestimate hemodialysis efficiency. This difference has to be considered when applying quantification of hemodialysis to clinical practice.