Comparison of fibrin hydrolysates and crystalline amino acid solutions in parenteral nutrition

Abstract

We have evaluated two solutions frequently used for intravenous hyperalimentation; one, a fibrin hydrolysate, the other, a synthetic crystalline amino acid mixture. We have studied two different levels of intake and evaluated the patient’s response by metabolic balance techniques and plasma amino acid ratios for limiting amino acids. Our results show that on a given nitrogen intake the fibrin solution was not as effective in nitrogen retention as the crystalline amino acid mixture. The peptides present in the hydrolysate appear to be poorly utilized as free valine and phenylalanine calculate to be limiting at a 10-g N intake and were shown experimentally to be limiting as judged by the plasma amino acid ratios. If the valine from peptides were available, this amino acid would not have been limiting. We did not observe this effect with the crystalline amino acid solution. The data suggest therefore that a much higher level of intake of the fibrin hydrolysate solution is required than when using the synthetic solution in order to achieve the same positive nitrogen balance and essential amino acid provision. The increased requirement of fibrin hydrolysate nitrogen over the calculated 12.1 g needed to provide the adult MDR of essential amino acids suggests that sepsis increased the MDR by 1.5 times.