[The importance of SpO2 and FIO2 for anesthetic management for Norwood's operation].

The systemic and pulmonary vascular resistance needs to be balanced before cardiopulmonary bypass (CPB) and high flow pulmonary circulation must be avoided after CPB during anesthetic management for Norwood's operation. The level of SpO2 was controlled at 75-80% to maintain systemic and pulmonary circulation. The relationship between the change of color of the lung and level of SpO2 through gradual increase of pulmonary blood flow was carefully observed. As SpO2 level increased, lung changed color from white, pink to red. The SpO2 level of lung in red color was above 85%, suggesting high flow pulmonary circulation. To decrease the level of SpO2, FIO2 was decreased. The lung changed to pink and balance of systemic and pulmonary circulation was maintained, reconfirming that control of SpO2 and FIO2 levels is important for this operation.