Metabolic evaluation of a 75% lipid/25% glucose high nitrogen solution for intravenous nutrition

OBJECTIVE: To compare the metabolic response to a 75% lipid/25% glucose regimen of intravenous feeding with that of a regimen of isocaloric isonitrogenous glucose alone. DESIGN: Randomised crossover study. SETTING: University department of surgery. SUBJECTS: 14 Patients (of 18 consecutive) who did not develop infections after major upper gastrointestinal operations. INTERVENTIONS: Patients received five days of each of two regimens, both of which provided 0.38 g nitrogen and 0.155 MJ (37 kcal)/kg/day. MAIN OUTCOME MEASURES: Nitrogen balance, prealbumin and transferrin concentrations, and basal efflux of amino acids from the lower limb before and after a five day course of each regimen. RESULTS: Mean (SD) nitrogen balance increased from -11.4 (2.6) g/day to 1.7 (4.1) and 1.6 (5.5) g/day after lipid/glucose and glucose alone, respectively (p < 0.0001). Basal prealbumin and transferrin concentrations increased after both regimens, but significantly so only after lipid/glucose (p < 0.01 and < 0.02, respectively). Mean (SD) net basal efflux of total amino acids from the lower limb was significantly reduced after both regimens, (p < 0.0001 in each case). Net basal alanine efflux was significantly reduced only by glucose alone, and basal glutamine efflux only by lipid/glucose (p < 0.05 in each case). Plasma free fatty acids were increased only by glucose alone (p < 0.001), and glucose alone augmented tissue uptake of glucose significantly more than lipid/glucose (p < 0.01 and < 0.05, respectively). CONCLUSIONS: The solution high in lipids and nitrogen was well tolerated. There was no difference in improvements in nitrogen balance or amino acid flux across the lower limb, but lipid/glucose was associated with higher increases in visceral protein concentrations.