[1]Department of Anesthesiology;
Hainan General Hospital;
Haikou570311;
China;
[2]Department of Anesthesiology;
The First Affiliated Hospital of Hainan Medical College;
Haikou570102;
China;
[3]Department of Anesthesiology;
Nanjing General Hospital;
Nanjing210002;
China;
[2]Department of Anesthesiology;
The First Affiliated Hospital of Hainan Medical College;
Haikou570102;
China;
[1]Department of Anesthesiology;
Hainan General Hospital;
Haikou570311;
China;
[4]Department of Anesthesiology;
The Second Hospital of Hebei Medical University;
Shijiazhuang050000;
China;
[4]Department of Anesthesiology;
The Second Hospital of Hebei Medical University;
Shijiazhuang050000;
China;
Old age; Total intravenous anesthesia; Anesthesia depth; MMSE score; Bispectral index; Plasma cortisol;