 Treatment Protocol Following informed consent, blood will be drawn pre-operatively for baseline characteristics methemoglobin, venous saturation, CBC, S100, gene expression profiles, BNP, cTnI, IL-6, IL-8, lactate, TNFalphaTable, Blood sample for Study. Intra-operatively we will use a standardized anesthetic protocol unless contraindicated by specific patient clinical characteristics. Intraoperative measurements will include: aortic cross clamp time, and total cardiopulmonary bypass time. Intraoperative hemodynamic measurements will include: mean systemic blood pressure MAP, central venous pressure, right atrial pressure pulmonary artery pressure, and pulmonary capillary wedge pressure when available. Blood samples will be drawn following CPB upon arrival to the ICU and will be analyzed as above. Repeat blood samples for each will be drawn again after 12, 24, and 48 hours. Patients will be followed to the time of discharge. Ventilator settings, length of ICU and hospital stay will be recorded. All measurements in both groups will be the same. Time points will be referenced from the time of admission to the PICU for both groups. 