Fatty acid composition of platelet membrane lipids after administration of two different fat emulsions in critically ill patients.

Abstract

To determine the effects on platelet membrane fatty acid composition following administration of two different fat emulsions. Prospective, randomized, double-blind study. Intensive care unit in a university-affiliated hospital. 12 adult critically ill patients in need of total parenteral nutrition. Patients were treated with total parenteral nutrition (TPN) for 7 days, receiving for fat intake either a long-chain triglyceride (20% LCT) emulsion (group 1, n=6) or a medium-chain triglyceride-LCT (20% MCT/LCT) emulsion (group 2, n=6). High-performance liquid chromatography of membrane fatty acids was carried out before and after 7 days of TPN. In the LCT group, an increase in C18:2n-6 and a decrease in caprylic acid and docosahexaenoic acid, which resulted in a decreased ratio of n-3/n-6 fatty acid content, was observed. In the MCT/LCT group, a reduced percentage of palmitoleic acid and arachidonic acid was shown. The observed changes in fatty acid composition are in agreement with the lipid composition of the fat emulsions used. Because the C18:2n-6/C18:3n-3 ratio in both emulsions is close (approximately 9.0), the observed changes in the fatty acid composition of platelets may not be relevant for platelet function.