A chylothorax is a collection of fluid around the lungs that can occur after cardiac surgery. The fluid contains chyle, a milky fluid consisting of fat droplets. The standard treatment is to feed an infant with a specialized low fat formula for up to 6 weeks until the chest has time to heal. This formula is generally not well tolerated and mother's of our patients have expressed a desire to continue using breast milk. A few case reports have been published, but there have not been any studies to date looking at this. Data will be collected to include information about nutrition, weight gain, teaching needs, surgical, hospital, and discharge information.