RecruitingPhase 3Drug trialEvaluation of Analgesia for Cardiac Elective Surgery in ChildrenThe purpose of this study is to look at a standardized methadone-based enhanced recovery after surgery protocol following pediatric cardiac surgery. This study will consist of randomly assigning children to receive the methadone-based recovery procedures or to receive current standard of care recovery procedures. Randomly assigning means that there is a 50/50 chance, like a coin flip, of being assigned to either research group.