Total Parenteral Nutrition with Intralipid in Pr Infants Receiving TPN with Heparin

Abstract

SummaryPlasma lipolytic activity (lipoprotcin lipase and hepatic lipase). free fatty acids (FFA). triglyceridcs. cholesterol, and glucose levels were measured in 21 premature infants [gestational age 26–37 weeks (mean ± SEM 30.4 ± 0.63 weeks), aged 1–8 days (mean ± SEM 3.00 ± 0.35 days)]. All infants were maintained on total parenteral nutrition with heparin (1 U/ml) and were given Intralipid, 1. 2, and 3 g/kg/day. over 15 h on days 1, 2, and 3. respectively. Blood samples were drawn before and at the end of Intralipid administration. Baseline plasma lipolytic activity, before the start of lipid infusion, was 1.54 ± 0.24 U/ml (1 U = I μmol [3H]oleic acid released from tri[3H]olein/h). Lipolytic activity increased after lipid infusion to 4.04 ± 0.96, 4.32 ± 0.63. and 6.09 ± 1.00 U/ml on days 1, 2, and 3 of the study. Hepatic lipase amounted to 38–47% of total lipolytic activity. During the 3 days of lipid infusion, there were dose‐dependent increases in plasma FFA, triglyceride, and cholesterol. Whereas FFA and triglyceride concentrations returned to prelipid infusion levels 9 h after stopping the infusion of Intralipid, 1, 2, or 3 g/kg, there was a cumulative increase in plasma cholesterol and glucose concentrations. The close correlation between FFA concentrations and plasma lipolytic activity (r = 0.655, p < 0.001) suggests considerable in‐travascular lipolysis. The positive correlation between plasma FFA and triglycerides (r = 0.632, p < 0.001) and FFA and cholesterol (r = 0.582. p < 0.001) indicate, however, that intravascular lipolysis does not prevent the lipemia associated with Intralipid infusion to low birth weight infants. This study suggests that the infusion of a mixture of small amounts of heparin and Intralipid leads to detachment of lipoprotcin lipase and hepatic lipase from the capillary endothelium of low birth weight infants. The resulting intravascular lipolysis probably exceeds the FFA disposal capacity of premature infants. The rise in plasma FFA concentration to 2.0 μmol/ml warrants caution in the combined use of Intralipid (at rates exceeding 2 g/kg/day) and low levels of heparin for the clinical management of premature infants maintained on total parenteral nutrition.