Mass balance: a quantitative guide to clinical nutritional therapy. II. The dialyzed patient.

The concepts of mass balance are extended to the nutritional management of the patient with chronic renal failure on dialysis. The use of these concepts permits estimation of protein catabolism from calculated rates of urea generation, using measurement of blood urea levels. Protein catabolic rate will equal intake in the stable patient (zero nitrogen balance), allowing for accurate nutritional screening in a large dialysis population for whom these values are available without individual dietary surveys. This has resulted in a four-fold reduction in routine monitoring of protein nutrition in such patients, freeing the dietitian to concentrate on specific problems. These concepts also comprise a key aspect of the National Cooperative Dialysis Study which seeks to maintain BUN at different levels in four carefully controlled modes of dialysis therapy. With these methods, the monitoring and control of BUN and protein intake has made the dietitian a pivotal member of this study staff.