Backgrounds: Monitoring of Bispectral index (BIS) has been regarded as useful to determine the degree of intraoperative hypnosis. Major factors of postoperative recovery after cardiac surgery include patient's recovery in cognitive function from the postoperative residual effects of anesthetics, such as opioids and sedatives, administered during intraoperative period. Therefore employing anesthetic regimens which can provide earlier recovery in cognitive function would be beneficial in facilitating fast-track cardiac surgery with earlier postoperative extubation and discharge from the intensive care unit (ICU).