Accuracy of hemodialysis urea kinetic modeling. Comparison of different models.
To test the accuracy of urea kinetic modeling (UKM), the classic fixed-volume model UKMf, two variable-volume models (UKMvb and UKMvd), direct dialysis quantification (DDQ) and a partial dialysate collection method (PDC) were evaluated in 15 stable, high-hematocrit patients. Urea generation rate (G) was also determined from a 1-week collection of total dialysate and urine (OWC). The results, except distribution volumes, were highly correlated. However, Kt/V, the normalized whole-body urea clearance, was about 8% higher with UKMvb and UKMvd. Two of three simple equations for Kt/V rendered grossly deviating, but highly correlating, results. The normalized protein catabolic rate was 8% higher with UKMvd. With OWC as reference, UKMvb and UKMvd overestimated G by 19 and 15%, respectively. All results of PDC closely followed those of DDQ. This method may be an alternative for exact quantification. Before using a new UKM method it should be compared to an established reference method.
Buur
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T
Department of Nephrology, University Hospital, Linköping, Sweden.
Larsson
R
R
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D007700:Kinetics; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D006435:Renal Dialysis; D014508:Urea / Q000378:metabolism*
D014508:Urea