A method for estimating nitrogen intake of patients with chronic renal failure

A method for estimating nitrogen intake of patients with chronic renal failure. A method for monitoring dietary compliance would be useful in treating patients with chronic renal failure (CRF). Nineteen nitrogen balances were measured while patients were eating unrestricted diets containing 6.4 to 15.1 g of nitrogen per day and 14 while patients consumed a 20 to 25 g mixed-quality protein ketoacid-supplemented diet containing 5.2 to 6.6 g of nitrogen per day. Urea nitrogen appearance (U) calculated as the sum of urinary urea nitrogen plus the variation in the body urea pool (using changes in serum urea nitrogen and either the 14 C urea space or 60% body weight) was correlated with nitrogen intake (r = 0.84). Both methods gave indistinguishable values for U. Total non-urea nitrogen excretion (NUN) and its components did not correlate with dietary nitrogen. NUN averaged 31.3 ± 2.1 mg N/kg/day and was not different between the two groups or in patients in neutral compared to those in mildly negative or positive nitrogen balance. Nitrogen balance calculated using estimated U and 31 mg N/kg/day was indistinguishable statistically from measured nitrogen balance. Thus, (1) U varies directly with dietary protein intake and can be estimated using urinary urea nitrogen, SUN, and body weight. (2) Total nitrogen excretion can be estimated accurately as U + 31 mg N/kg/day. (3) From the estimated total nitrogen excretion, dietary compliance of CRF patients in approximately neutral nitrogen balance could be assessed. Furthermore, if nitrogen intake were known, nitrogen balance could be estimated. Une methode pour estimer l'apport azote de malades en insuffisance renale chronique. Une methode de controle de la compliance alimentaire serait utile pour traiter les malades en insuffisance renale chronique (CRF). Dix neuf balances azotees ont ete mesurees alors que les malades consommaient des regimes libres contenant 6,4 a 15,1 g N/jour et que 14 malades consommaient un regime avec 20 a 25 g de proteines de mixtes, supplemente en ceto-acides, contenant 5,2 a 6,6 g N/jour. L'apparition (U) de l'azote ureique, calculee a partir de la somme de l'azote ureique urinaire et de la variation du pool ureique corporel en utilisant les changements de azote du uree serique et l'espace 14 C-uree ou 60% du poids corporel, etait correlee a l'apport azote (r = 0,84). Les deux methodes donnaient des valeurs identiques pour U. L'excretion d'azote non-ureique totale (NUN) et de ses constituants n'etait pas correlee a l'azote alimentaire. NUN etait en moyenne de 31,3 ± 2,1 mg N/kg/jour et n'etait pas different entre les deux groupes ni chez les malades en bilan azotee nul par rapport a ceux en bilan moderement negatif ou positif. Le bilan azote calcule en utilisant un U estime et 31 mg N/kg/jour etait indiscernable statistiquement du bilan azote mesure. Ainsi, (1) U varie directement avec l'apport proteique alimentaire et peut etre estime en employant l'azote ureique urinaire, BUN et le poids corporel. (2) L'excretion azotee totale peut etre estimee precisement par U + 31 mg N/kg/jour. (3) a partir de l'excretion azotee totale estimee, la compliance alimentaire de malades CRF en bilan azote a peu pres nul a pu etre appreciee. De plus, si l'apport azote etait connu, le bilan azote pouvait etre estime.