Abstract: SA-PO1010
Eliminating Routine Post-Dialysis Serum Urea Nitrogen Measurements in Hemodialysis: Testing a Proposed Method Using Conductivity Dialyzer Clearance to Determine Protein Catabolic Rate
Session Information
- Hemodialysis and Frequent Dialysis - V
November 09, 2019 | Location: Exhibit Hall, Walter E. Washington Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Dialysis
- 701 Dialysis: Hemodialysis and Frequent Dialysis
Authors
- Howard, John, University of California Davis Medical Center, Sacramento, California, United States
- Chin, Andrew I., University of California Davis Medical Center, Sacramento, California, United States
Background
Traditionally, pre and post-HD BUN measurements are used to determine Kt/V and normalized protein catabolic rate (PCRn). Timing and care of post-HD BUN sampling is critical for results to be accurate. A method of estimating PCRn without the post-HD BUN, utilizing conductivity clearance and only a pre-HD BUN, has recently been proposed. We tested this method in a cohort of patients in which online conductivity clearance monitoring (OCM) and clearance by usual formal kinetic modeling were measured.
Methods
We used a retrospective cohort of 39 patients totaling 271 HD treatments during which OCM and routine monthly laboratory tests with formal kinetic modeling for Kt/V and PCRn were performed. Data (including residual renal function) were entered into the Solute-Solver® version 2.11 online 2-pool kinetic modeling program. For volume of distribution of urea (V), we tested 3 values for each treatment: 1) average of 6 months prior kinetic model V; 2) Watson formula estimated V; and 3) Chertow formula estimated V. Output data of interest included the estimated post-HD BUN, spKt/V and PCRn based on these estimated values.
Results
The spKt/V by OCM underestimated that of formal kinetic modeling with a mean difference of 0.40, primarily driven by difference in V. The overall correlation of spKt/V was modest. Using pre-HD BUN with OCM to estimate PCRn as proposed by Daugirdas, we found a good correlation between PCRn by kinetic modeling and OCM method (Fig 1).
Conclusion
In this retrospective evaluation, the method using OCM without a post-HD BUN, as proposed by Daugirdas, appears to adequately estimate PCRn. The post-HD blood draw, subject to inaccuracies due to improper sampling technique, is potentially problematic in traditional determinations of HD adequacy and calculation of PCRn. OCM based calculations of Kt/V and PCRn remove this potential source of error. This process has practical applications and should be further validated.
Funding
- Clinical Revenue Support