[Use of the urea increment as an index of the effectiveness of parenteral feeding]

The influence exerted by the composition of intravenously introduced mixture of amino acids on so-called urea increment, i.e. the difference between the urea concentration in the blood on an empty stomach an on termination of its introduction, was studied in tests on adult mongrel male-dogs. On the other hand, upon introduction of an amino acids mixture imitating the Swedish preparation Vamin, which includes all essential and non-essential amino acids (except for glutamine and asparagine) in proportion as found in the egg white the urea increment values turned out to be inferior than on administration of a mixture containing from among essential amino acids only arginine and histidine, and from among non-essential ones-glycine and glutamic acid. The urea increment was also lower following combined introduction of an amino acids mixture together with an energy-producing (calorific) material, than when the latter was fed on prior to introduction of the mixture. The totality of findings suggests that as to its sensitivity to the composition of the parenterally introduced nutritional mixture and, possibly, dietary regimen-the urea increment is in no way inferior to the cumbersome, and difficulty realizable under clinical conditions method of nitrogen balance as a criterion for the efficacy of parenteral nutrition and deserves a detailed study as regards its clinical application.