Effect of Human Umbilical Cord-derived Mesenchymal Stem Cells on Non-cardiac Surgery-induced Lung Injury

Inclusion Criteria: * The electrocardiogram showed T wave change and ST segment depression * New York Heart Association (NYHA) Classification of cardiac function Ⅰ-Ⅱ level * The patient who first time to receive knee replacement * General anesthesia lasted about 2h * Signed informed consent Exclusion Criteria: * Does not meet the above selection criteria * Unable to sign the informed consent * Patients with a malignant tumor, other serious systemic diseases, or psychosis * Pregnancy, lactation, and those who are not pregnant but do not take effective contraceptives measures * The patient with a history of an allergic reaction to biological products or drug * The patient has any infectious diseases (including bacterial and viral infections) * The patient with cardiac pacemaker implantation within 3 months prior to enrollment * The patient who had a stroke within 6 months prior to enrollment * Unable to comply with the agreed timetable of this study * Patients who are participating in other clinical trials * Others who are clinically considered unsuitable for this treatment.