[Protein-sparing effect of various types of peripheral parenteral nutrition]

A randomized clinical study was performed postoperatively in a total of 47 patients comparing three different concepts of peripheral parenteral nutrition. Substituting 1 g amino acids (AA)/kg b.w. daily, the amount of carbohydrates (CH) was changed solely: gr. II no carbohydrates (sole AA-substitution), gr. III 2 g CH/kg b.w. (hypocaloric nutrition) and gr. IV 5 g CH/kg b.w. (basic nutrition). The influence on protein metabolism was examined by cumulative N-balances, various plasma proteins viscerally synthesized and serum amino acids predominantly utilised in peripheral tissues. In comparison to a non-fed-control group (I), hypocaloric nutrition showed the qualitative most favourable protein-sparing effect. Besides, 87% of N-retention serum levels of plasma proteins and amino acids investigated could be normalized completely. Peripheral basic nutrition also had a 88% rate of N-retention, however, only peripherally utilised amino acids were influenced beneficially whereas the plasma proteins remained depleted. Sole AA-substitution neither affected amino acid levels nor plasma proteins, and the N-retention rate was significantly lowered (67%). Possibly this type of therapy increases protein turnover solely, while true protein-sparing took place only with additional CH supply. However, a positive effect on visceral protein synthesis was observed exclusively with hypocaloric nutrition.