Dietary prescription based on estimated nitrogen balance during peritoneal dialysis

Abstract

Protein and energy requirements of children on automated peritoneal dialysis (APD) have still not been sufficiently well defined, although their adequacy is important to maintain a positive nitrogen (N) balance and prevent malnutrition. We carried out 42 studies to estimate N balance in 31 children over 3 years on APD for 19.8+/-15.7 months. Twenty metabolic studies were performed in patients dialysed for less than 1 year (7.2+/-3.3 months) and 22 in patients treated for more than 1 year (31.3+/-13.6 months). The mean estimated N balance of all metabolic studies was 57.5+/-62.8 mg/kg per day. In only 21 of 42 studies was N balance estimated to be over 50 mg/kg per day, which is considered adequate to meet N requirements for all metabolic needs and growth of uremic children. Estimated N balance correlated significantly with dietary protein intake (r=0.671, P=0.0001) and total energy intake (r=0.489, P=0.001). Using the equations of correlation, the values of dietary protein intake [=144% recommended dietary allowance (RDA)] and total energy intake (89% RDA) required to obtain an estimated N balance >50 mg/kg per day were calculated. Significantly lower estimated N balance values were obtained in the studies performed on patients on APD for over 1 year (36.09+/-54.02 mg/kg per day) than in patients treated for less than 1 year (81.11+/-64.70 mg/kg per day). In conclusion, based on the values of estimated N balance, we were able to establish adequate dietary protein and energy requirements for children on APD.

Kt/V and nPNA in pediatric peritoneal dialysis: a clinical or a mathematical association?

“…This is a common practice in nitrogen balance studies, assuming approximately 40-60 mg/kg of daily fecal losses of nitrogen and 15 mg/kg of daily cutaneous losses [31,32]. The resultant value should closely reflect daily protein catabolism, and when subtracted from DPI, will express the nitrogen balance for each patient [30,34]. This calculation should be of great value for the pediatric population, because the protein equivalent of nitrogen appearance that occurs in children differs from that seen in adults, mainly because children are growing, and they are not in a nutritional steady state as occurs in adult populations.…”

Nutritional management in the critically ill child with acute kidney injury: a review

“…There are few studies showing the correlation with clinical and patient outcomes, rather than the nutritional status [18][19][20][21][22] Body mass and composition parameters Total body nitrogen and potassium levels; energy beam-based methods; bioimpedence analysis All of these tests are research tools only. Moreover, they are costly and cumbersome [23][24][25][26][27][28][29][30] derived from dialysate glucose, estimated at 8-12 kcal/kg/day [37,38]. The estimated caloric load from a single 1.5-4.25 % glucose-based exchange can range from 50 to 300 kcal and can supply 30 % of the total daily energy intake of an adult patient undergoing PD [39].…”

“…Only a few studies describe the optimal amount of protein for children on acute PD and HD, and current data do not include all age groups. Recommended protein intakes for children on PD should be generous [37,38,62].…”

Peritoneal Dialysis in Children

“…Of note, in order to achieve a positive nitrogen balance and promote protein deposition, an adequate amount of nonprotein calories is required [87].…”

“…Energy intake should be at least 100 % of the recommended daily allowance (RDA) for children of the same gender and [192]. The calories derived from the absorption of glucose contained in the PD solutions can increase calorie intake by as much as 7-12 kcal/kg/day [87] and should be taken into account while calculating daily total energy intake if there is excessive weight gain [221,192].…”