Critically ill patients with
acute renal failure are traditionally treated with
low-protein diets to help control
uremia. This dietary approach may be deleterious to the patient's nutritional status and unnecessary, especially if continuous renal placement
therapies (CRRT) are used. However, the optimal amount of
protein supplementation during CRRT is unknown. In patients receiving CRRT, a high
protein intake may result in a positive
nitrogen balance in the absence of uncontrolled
uremia. Accordingly, we studied
nitrogen metabolism in two consecutive cohorts of
acute renal failure patients receiving equal amounts of calories but variable amounts of
nitrogen. One group received
protein according to the preferences of the attending clinician, the other a high and fixed amount of
protein (2.5 g/kg/day). Patients treated according to attending clinician preferences received significantly less
dietary protein (1.2 g/kg/day vs. 2.5 g/kg/day; p < 0.0001) and had a negative mean
nitrogen balance of -5.5 g/day. Patients receiving a high and fixed amount of
protein had a less negative mean
nitrogen balance (-1.92 g/day). Such patients were more likely to experience a positive
nitrogen balance during any 24-h period (53.6% vs. 36.7%; p < 0.05). They also required more aggressive
hemofiltration to maintain control of
uremia (mean ultradiafiltrate volume: 2145 mL/h vs. 1658 mL/h; p < 0.0001) and had a significantly higher but still acceptable mean plasma
urea level (26.6 mmol/L vs. 18 mmol/L; p < 0.0001). Survival was not significantly different in the two groups (37.5% vs. 31.3%). We conclude that a
high-protein diet can be safely administered to
critically ill patients with
acute renal failure receiving
continuous renal replacement therapy. Such a high
protein intake improves
nitrogen balance when compared to moderate
protein intake. A low
protein intake is unnecessary in patients treated with CRRT.