Abstract

Background: Statistical associations
between urea removal and survival have been described in a number of publications. Urea
removal during treatment may be quantified by the delivered dose of dialysis. Methods in
clinical use to measure delivered dose are retrospective and reliant on accurate blood
sampling. The new generation of single patient proportionating systems incorporate the
facility to automatically measure ionic dialysance throughout dialysis. Methods: In
a prospective study on 9 anuric patients with a stable dialysis prescription, we have
compared the agreement of the dose of dialysis determined from ionic dialysance (Dt/V)
with that derived from equilibriated Kt/V (eKt/V) and Kt/V measured by direct dialysis
quantification (Kt/V_DDQ) using 2 types of hemodialysis membrane (hemophan and
low-flux polysulfone). The variability of the delivered dose over a 1-month period was
also determined. Results: Ionic dialysance was independent of membrane type. It was
comparable to that established for plasma urea water clearance for hemophan but lower for
polysulfone (p < 0.001). The mean (± SD) delivered dose of dialysis (Dt/V) was similar
for both membranes (1.18 ± 0.15 (hemophan) and 1.18 ± 0.11 (low-flux polysulfone)).
Bland Altman comparisons showed the limits of agreement between Dt/V and Kt/V_DDQ
were ± 0.17 and for Dt/V compared with eKt/V ± 0.15. A 1-month measurement of Dt/V
demonstrated considerable treatment to treatment variability indicating that delivered
dose cannot be considered stable. Conclusion: The availability of online
measurement of ionic dialysance provides a step towards monitoring dialysis more closely
at the time of delivery, and its clinical application will ensure that a more constant
dialysis dose is delivered.

Author Details

Authors

• K.P. Katopodis
• N.A. Hoenich

Departments

• ¹ Department of Nephrology, School of Clinical Medical Sciences, Medical School, University of Newcastle upon Tyne, and Department of Renal Medicine, University Hospital of Ioannina, Greece, and
• ² Department of Nephrology, School of Clinical Medical Sciences, Medical School, University of Newcastle upon Tyne, Renal Research Laboratory, Renal Research Institute, New York, and Division of Nephrology and Hypertension, Beth Israel Medical Center, New York

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