Influence of exogenous fat emulsion on pulmonary gas exchange after major surgery.

The use of fat emulsion in total parenteral nutrition (TPN) is closely related to changes in respiratory function. The aim of this study was to evaluate the influence of exogenous fat emulsion on pulmonary gas exchange in the early period after major surgery. Total parenteral nutrition was administered to 18 patients for 6 days after esophagectomy for carcinoma. Half of the patients received glucose (glucose group), and the other half received glucose and fat (fat group). The fat emulsion was continuously infused for 24 hours over 6 days. Glucose utilization was significantly higher in the glucose group than in the fat group. Fat utilization was significantly higher in the fat group than in the glucose group. Carbon dioxide (CO2) production and respiratory quotient were significantly decreased in the fat group compared to the glucose group. There were no differences in the pulmonary vascular resistance index or alveolar-arterial difference in oxygen tension between the two groups. Although exogenous fat emulsion utilized as energy substrate decreases CO2 production after major surgery, it does not clinically influence the pulmonary hemodynamics or diffusion capacity.