Adequacy of haemodialysis and nutrition in maintenance haemodialysis patients: clinical evaluation of a new on-line urea monitor

Abstract

BACKGROUND: Recent developments in urea sensing monitoring show a good agreement between on-line and direct dialysis quantification which permits evaluation of both effective dialysis efficiency and protein catabolic rate of dialysis patients. METHODS: Fifty chronic haemodialysis patients were enrolled in a prospective study using an automatic urea sensing monitor operating on spent dialysate (U.M. 1000, Baxter). Dietary protein intake (DPI) and energy intake (DEI) were carefully evaluated by a skilled dietitian over 1 week. During this run U.M. 1000 was used to provide urea mass removed, effective Kt/V, and normalized nPCR. Blood samples were drawn pre- and post-dialysis for classical blood-based single pool Kt/V calculations at each session. RESULTS: For all patients results were as follows (mean +/- SD): Effective Kt/V 1.4 +/- 0.3, nPCR 1.2 +/- 0.3 g/Kg/day, DPI 1.2 +/- 0.3 g/Kg/day and DEI 30.1 +/- 7.2 Kcal/kg/day; blood-based single pool Kt/V 1.5 +/- 0.3. A strong correlation was found between nPCR and DPI for the 50 patients over 1 week (r = 0.75, P < 0.0001) and between effective Kt/V and single pool calculated Kt/V (r = 0.76). CONCLUSIONS: Urea Monitor 1000 is easy and convenient to use and there was a good correlation of the predialysis BUN and effective Kt/V with standard blood-side measurements. In stable haemodialysis patients who are not strongly catabolic or anabolic, the urea monitor measurement of nPCR correlated with DPI measured by a 7-day dietary record.