A Study Evaluating the Efficacy and Safety of IV L-Citrulline for the Prevention of Clinical Sequelae of Acute Lung Injury Induced by Cardiopulmonary Bypass in Pediatric Patients Undergoing Surgery for Congenital Heart Defects

Inclusion Criteria: * Patients, parents, or legal guardian willing and able to sign informed consent * Male and female subjects aged ≤18 years of age (females of child-bearing potential willing to practice an acceptable form of birth control) * Patients undergoing cardiopulmonary bypass for repair of a large unrestrictive ventricular septal defect, an ostium primum/secundum atrial septal defect, or a partial or complete atrioventricular septal defect * Pre-operative echocardiogram confirming cardiovascular anatomy and defect to be repaired Exclusion Criteria: * Evidence of pulmonary artery or vein abnormalities that will not be addressed surgically. Specific abnormalities excluded include: * significant pulmonary artery narrowing not amenable to surgical correction * previous pulmonary artery stent placement * significant left sided AV valve regurgitation not amenable to surgical correction * pulmonary venous return abnormalities not amenable to surgical correction * pulmonary vein stenosis not amenable to surgical correction * Preoperative requirement for mechanical ventilation or IV inotrope support * Presence of fixed or idiopathic pulmonary hypertension (i.e. Eisenmenger's Syndrome) prior to surgical repair * Pre-operative use of medications to treat pulmonary hypertension * Pregnancy; Sexually active females of child-bearing potential must be willing to practice an acceptable method of birth control for the duration of study participation (e.g. oral contrac…