The nitrogen load is affected by high protein provision according to kidney function in critically ill patients.

Adequate protein delivery is recommended in the acute phase of critical illness with kidney dysfunction. However, the influence of the protein and nitrogen loads has not yet been clarified. Patients admitted to the intensive care unit were included. In the former period, patients received standard care (0.9 g/kg/day protein). In the latter, patients received the intervention of active nutrition therapy with high protein delivery (1.8 g/kg/day protein). Fifty patients in the standard care group and 61 in the intervention group were examined. Maximum blood urea nitrogen (BUN) on days 7-10 were 27.9 (17.3, 38.6) vs 33 (26.3, 51.8) (mg/dl) (p = 0.031). The maximum difference in BUN increased [31.3 (22.8, 55) vs 50 (37.3, 75.9) mg/dl (p = 0.047)] when patients were limited to an estimated glomerular filtration rate (eGFR) <50 ml/min/1.73 m². This difference increased further when patients were limited to eGFR <30 ml/min/1.73 m². No significant differences were observed in maximum Cre or in the use of RRT. In conclusion, the provision of 1.8 g/kg/day protein was associated with an increase in BUN in critically ill patients with kidney dysfunction; however, it was tolerated without the need for RRT.