The heart is the “main engine” of the human body, so heart surgery is of course more risky than surgery on other organs. The overall post-operative recovery includes two major areas: a. Heart function: It can be simply understood as heart rate and blood pressure, under the maintenance of small to medium doses of cardiac drugs, the heart rate and blood pressure are stable, which is a more ideal state. If the application of high doses of cardiac drugs, indirectly suggest poor cardiac function. Second, lung function: lung is the second heart of the human body, after surgery generally need ventilator-assisted breathing, when the heart function is stable, lung function recovery, to remove the ventilator. So, going to the ventilator is also a very important hurdle. Is the ventilator removed to pass the dangerous period? No, it is not. Normal people are ventilated by negative pressure, while ventilators are ventilated by positive pressure, which turns out to be different. After the ventilator is removed, the child starts to breathe on his own, and the mode of ventilation changes, which requires adaptation, especially in cases of preoperative pneumonia, postoperative sputum, young age, complicated precordial surgery, combined pulmonary hypertension, etc. It is easy to fail to withdraw the ventilator, that is, to bring it back after removing it, and if you need to bring it again, the doctor will tell you.