After cardiac surgery, the patient’s condition is relatively unstable and there is a risk of accidents, so the vital signs need to be monitored dynamically in order to detect and deal with some unexpected situations such as bleeding, hypertension, arrhythmia, electrolyte disorders, cardiac insufficiency, etc. The ICU of cardiac surgery is equipped with advanced equipment such as artificial ventilators, cardiac monitors, invasive arterial blood pressure monitoring systems, cardiac output monitors and other advanced instruments, as well as a specialized training of the care unit doctors box breathing medical and nursing care to ensure that patients can safely pass through the postoperative period.