The purpose of this study is to determine whether preoperative administration of Modified Tian Wang Bu Xin Dan Hydrogel Patch prevents the incidence of postoperative delirium in elderly patients undergoing major surgery.

The Traditional Chinese Medicine (TCM) Tian Wang Bu Xin Dan (TWBXD, Cheonwangbosimdan), first recorded in Effective Formulae Handed Down for Generations ( Shi Yi De Xiao Fang) in 1337, is a herbal medicine that has been continuously utilized in Chinese medicine. It alleviates insomnia, anxiety, and palpitation by furnishing energy and stabilizing patients' mind. Cheonwangbosimdan can mitigate primary insomnia and secondary insomnia in patients with hyperthyroidism and menopause without severe side effects.

Tianwang Buxin Decoction has the same effect as Olanzapine for the treatment of delirium after hip joint replacement in falling-induced senile femoral neck fracture patients.

This study aim to evaluate the incidence of postoperative delirium in elderly patients treated with prophylactic Modified Cheonwangbosimdan Hydrogel Patch versus placebo patch.

Inclusion Criteria:

1. Patients' age ≥70 years;
2. Underwent elective non-cardiac surgery (including Orthopedics, thoracic, urology, general surgery patients)under general anesthesia ;

Exclusion Criteria:

1. History of neuropsychiatric diseases including delirium, mental disorders, Parkinson, dementia, etc.;
2. The operation was cancelled due to various reasons after the patient was enrolled;
3. severe liver disease; severe renal dysfunction defined as either having creatinine clearance < 30 ml/min or being dialysis-dependent;
4. Patients who undergo second operation in a short period;
5. Past 30-day prescribed use of sedative-hypnotics for the indication of insomnia;
6. History of alcohol abuse or a history of drug dependence;
7. Cannot with the completion of tests of cognitive function;
8. Known allergy to skin patch;
9. Treatment site has active skin lesion or inflammation;
10. Refused to participate in the study.