Nutrition
-
Metabolic and hemodynamic measurements performed in 72 septic (S) and 40 nonseptic (NS) surgical patients undergoing total parenteral nutrition were analyzed to assess the role of substrate supply as a determinant of O2 extraction (O2Ex). In S, O2Ex was inversely related to cardiac index (CI); at any given CI, significant increases in O2Ex with simultaneous increases in O2 consumption (VO2) were related to increasing doses of amino acids, with a less remarkable effect of fat and no effect of glucose dose. ⋯ The increase in VO2 per gram of administered amino acids, at any CI and O2 transport index, was 817 ml in S and 267 ml in NS. These results suggest that the impaired O2Ex and VO2 in S may at least partly reflect abnormalities in substrate utilization and that amino acid support may have a role in modulating these abnormal O2Ex patterns by providing preferential substrate for oxidative metabolism.