Total parenteral nutrition with high or low nitrogen intakes in patients with acute renal failure

This study was undertaken to assess the clinical and metabolic responses to total parenteral nutrition (TPN) in patients with acute renal failure who could not be nourished adequately through the enteral tract. The TPN provided either about 21 g/day of essential amino acids (EAA) or a larger quantity of essential and nonessential amino acids (ENAA); the ratio of essential to nonessential amino acids in the latter preparation was 1.0:1.0. Attempts were made to give sufficient ENAA nitrogen to equal or slightly exceed the urea nitrogen appearance (UNA). Five patients were randomly assigned to receive TPN with EAA (2.3 g of nitrogen per day) and six patients to receive ENAA (11.3 g of nitrogen per day). Hypotension with trauma or infarcted intestine was the cause of acute renal failure in 10 of the 11 patients. Three of the five patients receiving EAA recovered renal function, and two survived. In the patients receiving ENAA, as compared with those given EAA, UNA was significantly greater (14 +/- 7.4 [SD] vs. 7.5 +/- 3.0 g/day; P less than 0.01), and nitrogen balance, estimated from the difference between intake nitrogen and UNA was slightly, but not significantly, less negative (-3.0 +/- 4.0 vs. -5.2 +/- 2.9 g of nitrogen per day). These preliminary findings suggest that in comparison to TPN with EAA, there is no advantage to larger amounts of ENAA (76 +/- 13 g/day). Studies are indicated to assess whether a multifaced approach using TPN with ENAA and possibly a larger proportion of the branched-chain amino acids, higher energy intakes, anabolic agents, and continuous arterio-venous hemofiltration will improve morbidity and mortality in patients with acute renal failure.