Influence of rapid amino acid and lipid emulsion administration on gas exchange and resting energy expenditure.

The aim of this study was to observe the effect of rapid lipid and amino acid infusion on resting energy expenditure (REE) in patients on parenteral nutrition. Eight people were studied. After 8 h of saline administration, they received 20% lipid emulsion and 8% amino acid solution during the next 5 h (rate 3.8 mg.kg-1.min-1 fat and 1.9 mg.kg-1.min-1 amino acid). Before the onset of the infusion and 3 and 5 h after, gas exchange and REE were measured. The rapid lipid emulsion administration led to a significant rise in serum triglyceride level. A significant increase in VO2 (from 269.0 +/- 66.8 to 319 +/- 55.8 ml/min) and REE (from 1858 +/- 438 to 2155 +/- 385 kcal/24 h) was observed 5 h after the onset of substrate administration (P less than 0.01). Pulmonary ventilation and VCO2 production were not influenced by the infusion. The thermic effect of nutrients administered reached 3.5 and 6.5% 3 and 5 h after the start of infusion, respectively. We conclude that REE can be increased by the rapid administration of lipid-based parenteral nutrition.