Estudio comparativo de dos métodos de extracción del nivel de nitrógeno ureico post hemodiálisis para el cálculo del kt/v

Abstract

Objective: To assess whether there are differences in Kt/V calculation between two post-HD BUN sampling methods.
Methodology: Comparative prospective study in a cohort of chronic haemodialysis patients. For two consecutive weeks Kt/V was quantified using the second-generation Daugirdas formula. The blood sample for the post-haemodialysis BUN was taken using 2 methods: reduction of blood pump flow to 50ml/min for 2 minutes, immediately before the end of the session (method A); and 10 minutes after the end of the haemodialysis session (method B).
Results: 47 patients studied: 66% men, average age of 66±13 years, 51% IAVF, 59.5% on-line haemodiafiltration. The mean Kt/V for the two weeks of the study for method A was 1.51 and for method B was 1.41 (p<0.001). There were statistically significant differences between the two methods according to the haemodialysis technique and vascular access. However, the Pearson correlation coefficient showed an almost linear correlation between the average Kt/V obtained using both methods (r=0.954). The difference between the two methods was 10%.
Conclusions: There are significant differences in the Kt/V calculation between post-haemodialysis BUN sampling using method A and B, with the higher dose obtained when the first method is used. However, both measurements are well correlated, taking into account that with sampling after 10 minutes there is a reduction of 10% compared to the other method.