The effect on protein and amino acid metabolism of an intravenous nutrition regimen providing seventy percent of nonprotein calories as lipid.

BACKGROUND

The purpose of this study was to determine which peripheral intravenous nutrition (IVN) regimen, one containing 70% nonprotein calories as lipid IVN or one containing all nonprotein calories as glucose IVN, was most effective at reversing some effects of surgery on protein metabolism.

METHODS

Twenty patients who required IVN after operation were randomized into two well-matched groups that received 36 kcal.kg-1.day-1 glucose IVN or 37 kcal.kg-1.day-1 lipid IVN.

RESULTS

Both IVN regimens resulted in similar changes of nitrogen balance, plasma liver enzymes, blood urea, plasma albumin, and plasma prealbumin. Mean plasma transferrin rose significantly after glucose IVN (p less than 0.01), a change greater than that after lipid IVN (p less than 0.05). Lipid IVN resulted in continued net efflux of alanine from peripheral tissues at rates similar to pretreatment values; glucose IVN significantly reduced net alanine efflux (p less than 0.05). Most of the extra alanine produced by peripheral tissues during lipid IVN appeared to derive from an increased uptake of intramuscular glutamate and from an increased uptake of branched chain amino acids.

CONCLUSIONS

The results of this study indicate that 38 kcal.kg-1.day-1 lipid IVN was equivalent to glucose IVN, except for the continuing gluconeogenesis of alanine and the delayed recovery of plasma transferrin concentration after surgery. A greater infusion rate of such a regimen may be necessary to provide sufficient glucose to suppress gluconeogenesis.