Characterization of fatty acid clearance in premature neonates during intralipid infusion

This study reports the clearance of plasma triglyceride and phospholipid fatty acids during Intralipid 20% infusion (Pharmacia, Sweden) in nine ventilated preterm infants receiving parenteral nutrition. Blood samples were taken during lipid infusion and over a subsequent period of 36 h of fat-free parenteral nutrition. Plasma triglyceride fatty acids showed a uniform and rapid decline after lipid was stopped from the peak values recorded during infusion. In contrast, plasma phospholipid fatty acids showed a variable decline during fat-free nutrition. This variability appeared to be the result of a differing contribution of infused egg yolk phospholipid fatty acids to the measured plasma values, and to changing fatty acid composition of endogenous phospholipid in response to fat free nutrition. Red cell phospholipid fatty acid composition was stable over the 36-h clearance study period. These results indicate the complexity of interpretation of plasma fatty acids during lipid infusion. We conclude that red cell phospholipid fatty acids provide the only stable measure of tissue fatty acid composition in parenterally fed preterm infants.