Hypoxemia is a common and potentially serious postoperative complication. Hypoxic encephalopahty may occur in prolonged hypoxemia. This condition needs brain protection. There are many brain protective methods. The primary cental nervous system protective mechanism of the barbiturates is attributed to their ability to decrease the cerebral metabolic rate, thus improving the ratio of oxygen (O2) supply to O2 demand. The electroencephalogram-derived bispectral index system (BIS) is a promising new method to predict probability of recovery of consciousness. We experienced two cases of hypoxic brain damage in recovery room. The patients were treated with thiopental and monitored with BIS. The use of thiopental as brain protection during complete global ischemia after cardiac arrest was not effective.