Plasma amino acid concentration changes after total parenteral nutrition (TPN) interruption in critically ill and surgical neoplastic patients

Fourteen patients with mild to moderate catabolism due to accidental or surgical trauma and eight neoplastic patients were treated with early, short term TPN immediately after injury or surgery. Patients were given nitrogen, 0.35 g kg−1 day−1 and glucose, 35 kcal kg−1 day−1. The plasma amino-acid patterns during treatment and after its discontinuation were investigated and appeared to be predominantly determined by the composition of the administered amino acid solution. When the treatment was stopped the plasma concentration of the infused amino acids and of Ornithine (not administered) fell towards the initial values. The time needed to reach the pretreatment plasma concentration depended on the amino-acid solution used and varied between 3 and 6 h for different amino acids. When investigating plasma amino-acid concentration this time delay should be accounted to differentiate the effect of TPN and of the underlying pathology.