This study is a blinded, randomized, controlled prospective trial comparing immune response (sepsis, inflammatory response, pulmonary vasoconstriction) in 2 groups of infants less than 3-month old receiving pre and post cardiopulmonary bypass surgery. The infants will receive 1 out of the 2 following intravenous lipid preparations: Soybean Oil (n-6), or a combination of Medium Chain Triglyceride i.e. coconut oil, Long Chain Triglyceride i.e. Soybean Oil, and Fish Oil (MCT:LCT:FO). There will be 16 subjects in each group.

Inclusion Criteria:

• 36 weeks gestation
• 3 months corrected age
• appropriate for gestational age (AGA)
• admitted for surgical correction of congenital heart defects (single ventricle, tetralogy of Fallot, truncus and complex biventricular repairs)
• enteral nutrition at 30 kcal/kilogram/day

Exclusion Criteria:

• 5 minute Apgar score of 4
• major congenital defect other than heart defect
• presence of significant neonatal morbidity (intraventricular hemorrhage (IVH) grade 3 or greater, necrotizing enterocolitis (NEC) and surgical abdomen)
• any metabolic disorder
• any endocrine disorder
• medications which alter eicosanoid metabolism including indomethacin, acetylsalicylate (with exception of steroids which will be analyzed independently)