One of the limiting factors in treating infants undergoing cardiac surgery is the difficulty in assessing systemic perfusion with accuracy. At Children's Healthcare of Atlanta, Near-infrared Spectroscopy (NIRS) is available, but has never been studied. In patients undergoing first stage palliation (Norwood) for hypoplastic left heart, routine management will be utilized in addition to the NIRS monitor. The following will be documented pre- and post-bypass, then every 4 hours for 24 hours after admission to the Cardiac Intensive Care Unit:NIRS readings, Lactic acid levels,mixed venous saturations,hemoglobin, hematocrit, arterial blood gases, heart rate, blood pressure, central venous pressure, left atrium pressure,core temperature, toe temperature, pulse oximeter reading, urine output, ventilator settings, inotropic levels. All the data will be entered into a database and analyzed.