Lipid metabolism in the neonate. II. The effect of Intralipid on bilirubin binding in vitro and in vivo.

The relationship between Intralipid fat emulsion and the binding of bilirubin to protein and cells was studied in vitro and in vivo. In the in vitro system, Intralipid had no beneficial effect in augmenting billirubin binding in adult whole blood. The unmetabolized Intralipid had no adverse effect on bilirubin binding in vitro. Twenty-seven neonates were infused with Intralipid (1 gm/kg) over a 4-hour period; the SGA infants achieved very high plasma concentrations of free fatty acids. When the molar ratio of free fatty acids to albumin in plasma was greater than six, the free fatty acids displaced bilirubin from albumin, resulting in the generation of free bilirubin. It is suggested that the molar ratios of free fatty acids to albumin in plasma be followed in any infant who is receiving Intralipid and that the dose of Intralipid be adjusted to maintain this ratio below six.