The initiate drug concentration of etomidate is set to 0.2 μg/ml, increasing 0.1 μg/ml every minutes until the BIS(Bispectral index ) reaches 40~60.

BIS monitored from beginning of anesthesia induction to the end of the surgery.

Midazolam 0.03 mg/kg injection vein，Sufentanyl 0.5~1 μg/kg, target controlled infusion of etomidate or propofol,after the consciousness of patients is lost, rocuronium 0.6mg/kg is given.

After the intubation, target controlled infusion(TCI) of etomidate or propofol is maintained,rocuronium 0.15mg/kg and sufentanil is given when needed. When the operation is over, the TCI is stopped.

After the induction of anesthesia, Tracheal intubation is performed.

Using Confusion Assessment Method for the Intensive Care Unit(CAM-ICU) to screening of delirium.

using the Activities of Daily Living (ADL) to assess the life quality one month after the surgery.

Number of Participants with Serious and Non-Serious Adverse Events including major adverse cardiovascular and cerebrovascular event such as cardiac infraction,stroke, acute renal failure, re-surgery,and death.

Safety Issue?: Yes

BIS is monitored and recorded at 9 time points, including 10 minutes before induction,the right moment after induction of anesthesia and tracheal intubation,the beginning of surgery and the cardiopulmonary bypass(CPB),the time the ascending aorta is blocked and unstuck,the time the CPB and the surgery is over.

The time period from TCI etomidate or propofol to the disappearance of eyelash reflex.

pulse blood oxygen saturation is monitored and recorded at 9 time points, including 10 minutes before induction,the right moment after induction of anesthesia and tracheal intubation,the beginning of surgery and the cardiopulmonary bypass(CPB),the time the ascending aorta is blocked and unstuck,the time the CPB and the surgery is over.

record the dosage of the anesthesia drug including propofol and etomidate, sufentanyl and rocuronium used during the period of maintenance of anesthesia.