NUTRITIONAL-REQUIREMENTS BASED ON SUBSTRATE FLUXES IN TRAUMA

The metabolic requirements of the severely injured patient dictate the appropriate nutritional support. There is an increase in energy expen diture by the injured person that is associated with increased protein catabolism. The injured patient also utilizes increased amounts of ca rbohydrate and lipid. The proportions of carbohydrate and lipid utiliz ed appear to depend on the relative amount of calories provided to the injured subject. Measurement of energy expenditure in patients receiv ing glucose indicates that at most 60% of the expired CO2 is derived f rom glucose oxidation. Because protein oxidation contributes approxima tely 20% of the expired CO2, lipid oxidation contributes the remaining 20% of the expired CO2. Therefore, the injured patient should be prov ided with sufficient calories in the proportion 60% glucose, 20% prote in, and 20% lipid.