The impact of intravenous fat emulsion administration in acute lung injury

The aim of this study was to evaluate the effect of parenteral nutrition containing medium- and long-chain triglycerides on the function of the respiratory system and to investigate mechanisms involved in this process. We studied 13 patients with acute respiratory distress syndrome (ARDS), 8 receiving lipid and 5 placebo, and 6 without ARDS, receiving lipid. Bronchoalveolar lavage (BAL) was performed before and 1 hour after administration of lipid or placebo. In patients with ARDS, lipid administration resulted in deterioration of oxygenation (Pa-O2/Fi(O2): from 129 +/- 37 to 95 +/- 42), compliance of respiratory system (from 39.2 +/- 12 to 33.1 +/- 9.2 ml/cm H2O), and pulmonary vascular resistance (from 258 +/- 47 to 321 +/- 58 dyne.s.cm(-1)). In the BAL fluid of the same group, an increase in total protein and phospholipid concentrations, phospholipase activities, platelet-activating factor and neutrophils, as well as alterations in BAL lipid profile were observed. No significant changes were observed in the control or in the ARDS-Placebo groups. In conclusion, this study indicates that administration of medium- and long-chain triglycerides in patients with ARDS causes alterations in lung function and hemodynamics. Inflammatory cells, possibly activated by lipids, release phospholipase A(2) and platelet-activating factor, enhancing edema formation, inflammation, and surfactant alterations.