 This study proposes a randomized controlled trial of the use of glucocorticoids to improve the clinical course of neonates post-cardiopulmonary bypass CPB. The study will focus on neonates for a few reasons. Although their post-CPB clinical course is typically more severe and intensive care unit ICU care more prolonged than older children, their modes of morbidity are also well characterized. Further, the high level of severity itself provides a substrate for identifying the positive effects of a particular therapy. Finally, a therapy identified as beneficial has the greatest potential for benefit in this vulnerable population. The well characterized scenario of low cardiac output syndrome LCOS will be used as the primary endpoint, while a variety of secondary endpoints will be related to the biochemical anti-inflammatory effects of therapy, ICU care and late neurological outcome. 