①The first adjustment requires electrical stimulation to break through the skin barrier. The first intervention is the day before the operation. The initial electrical stimulation frequency is 30Hz and the pulse width is 300μs. The frequency and pulse width are adjusted according to the individual feelings of the subject until they are tolerated by the subject. Maximum current stimulation without discomfort and lasting for 30 minutes; ② second time For the intervention, the subject is connected to the monitor after entering the surgery room. After observing that the subject's vital signs are within the normal range, the same stimulation frequency as the first time is immediately given for 30 minutes; ③ The third intervention is after the subject's surgery is completed. The same stimulation frequency was given in the resuscitation room until the patient was extubated and resuscitated.

① The first intervention is also the day before the operation. The frequency and pulse width are adjusted three times without turning on the machine, and the subject is asked if they have any feelings. After adjusting the frequency three times, no operation is performed for 30 minutes; ② The second intervention For the first intervention, after the monitor is connected in the operating room, the frequency and pulse width are not set, and it lasts for 30 minutes before being taken out; ③ For the third intervention, after the subject's surgery, earplugs are inserted in the recovery room, and the frequency and pulse width are not set. Remove the earplugs after extubation resuscitation is completed.

①The first adjustment requires electrical stimulation to break through the skin barrier. The first intervention is the day before the operation. The initial electrical stimulation frequency is 30Hz and the pulse width is 300μs. The frequency and pulse width are adjusted according to the individual feelings of the subject until they are tolerated by the subject. Maximum current stimulation without discomfort and lasting for 30 minutes; ② second time For the intervention, the subject is connected to the monitor after entering the surgery room. After observing that the subject's vital signs are within the normal range, the same stimulation frequency as the first time is immediately given for 30 minutes; ③ The third intervention is after the subject's surgery is completed. The same stimulation frequency was given in the resuscitation room until the patient was extubated and resuscitated.

Trained researchers will draw 3-5ml blood samples before surgery, on the first day after surgery, and on the third day after surgery and store them in vacuum blood collection tubes containing lithium heparin. They will be temporarily stored in a refrigerator at 2-8°C within 24 hours. Sent to laboratory for analysis. All blood samples were analyzed by staff who received professional training in detecting Hs-cTnT using the Roche cobas e411 electrochemiluminescence fully automatic immunoassay analyzer.

The 30-day MINS follow-up after surgery includes whether the patient has symptoms of myocardial ischemia such as chest tightness, angina pectoris, myocardial infarction, etc. It is also recommended that the patient come to the hospital for review of electrocardiogram and hs-cTnT and other indicators. Combining the current manufacturer-defined abnormal thresholds and the latest MINS study recommendations, we define MINS diagnostic criteria as hs-cTnT levels exceeding 14 ng/L during noncardiac surgery or within 30 days after surgery, and are at least 1 higher than the preoperative hs-cTnT level