Benefits of Parenteral Lipid Emulsions in Acute Respiratory Failure

Lipid emulsions in parenteral nutrition can interfere with pulmonary functions in patients displaying anomalies of the ventilation-perfusion ratio. The underlying mechanisms are unknown, but involve modifications of the production of vasoconstrictor and vasodilator eicosanoids as an effect of lipid infusion. Preferential synthesis of one or other of the eicosanoid types depends on the rate of administration of the lipids. Slow flow, corresponding to the administration of 100 g of triglycerides in 10-12 hours, leads to no change in the ventilation/perfusion ratio, and has no effect on gas exchange. TCM-based emulsions, which have little interference with eicosanoids, can be administered during ARDS. However, they have few benefits over a soy emulsion administered slowly. A new finding concerning lipid emulsions is the capacity of emulsions rich in long-chain polyunsaturated fatty acids of the n-3 series (DHA and EPA), derived from fish oil and of borage oil rich in gammalinoleic acid, to affect pulmonary inflammation and bronchial reactivity. These factors open up new and promising perspectives in the prevention and treatment of ARDS.