What is extracorporeal circulation? Extracorporeal circulation, also known as cardiopulmonary bypass, is the process of drawing blood out of the body, exchanging it for oxygen and carbon dioxide gas through an artificial oxygenator (the same principle as the lungs), and then using a mechanical pump (extracorporeal circulation machine, instead of the heart pumping function) to deliver the blood back to the body to supply systemic blood circulation. The technology of extracorporeal circulation has been gradually developed since the 1950s, and the cause of extracorporeal circulation in China has also started since then. This is a new type of extracorporeal circulation machine Extracorporeal circulation came into being with cardiac surgery, and it has been 56 years since the first case of extracorporeal circulation in the world. During this period, extracorporeal circulation has developed from a simple technology to a comprehensive clinical discipline, and its theory, practice, equipment and materials have all undergone great changes. The development of extracorporeal circulation has in turn contributed to the development of cardiovascular surgery. At the beginning of the development of extracorporeal circulation, people could only do the simplest cardiac surgery, such as atrial septal defect repair, but nowadays, cardiovascular surgery with the support of extracorporeal circulation can solve almost all cardiac and macrovascular surgical problems. What is deep cryostasis? Deep hypothermic stop circulation means that after cooling the body to deep hypothermia (generally below 18℃ for nasopharyngeal temperature and below 20℃ for anal temperature), the body completely or partially stops blood circulation, and then resumes blood circulation and warms up to normal body temperature when the surgical operation is performed to a certain extent. Deep hypothermic body circulation is a complex and difficult management technique in extracorporeal circulation, and is commonly used for surgery of coarctation aneurysms with lesions involving the aortic arch. At present, conventional extracorporeal circulation and deep hypothermic stop circulation have been used for many years in China, which is technically mature and clinically effective, and can enable patients to safely pass through the V.I.C. period. Can the heart beat well after the “open” heart surgery? Usually congenital heart disease such as atrial septal defect, ventricular septal defect, tetralogy of Fallot correction and heart valve surgery such as mitral valve replacement (or molding), aortic valve replacement (or molding) are required to stop the heart beating under the support of extracorporeal circulation, and then cut the heart for surgery, medically called it cardiotomy, cardiotomy on the heart is a considerable damage, then the heart can resume beating after surgery Can the heart beat again after surgery? Sometimes the cardiotomy takes a long time, several hours, during which the heart is at rest, can the heart resume beating after the operation? Is there any impairment of cardiac function? Cardiac surgery and prolonged cardiac arrest do cause damage to the heart, and cardiac function may be damaged to varying degrees, but don’t worry, modern cardiovascular surgery and extracorporeal circulation have sophisticated cardioprotection measures, known as myocardial protection, which can be applied correctly to minimize damage and allow the heart to resume beating after surgery and maximize protection of cardiac function. How exactly does myocardial protection work? There are three usual methods of myocardial protection: first, stopping the heart from beating; second, cooling the heart; and third, giving myocardial protection drugs. The specific steps are: open the chest to expose the heart and arteries and veins, arterial and venous cannulae to establish extracorporeal circulation, instill sufficient amount of myocardial protection fluid at about 4℃ into the heart’s own blood vessels, the special myocardial protection fluid is added with drugs to stop the heart and drugs to nourish the heart muscle, so that soon the heart stops beating, the heart becomes cold, and is filled with various drugs for myocardial protection, after the first instillation of myocardial protection fluid After the first instillation of myocardial protective fluid, the heart is re-infused with myocardial protective fluid at regular intervals, and the surface of the heart is covered with ice chips to keep the heart in a cold state during the procedure. These steps are not enough; perfect myocardial protection cannot prevent damage to cardiac function. After the heart has been sutured and regained circulation, it will need extracorporeal support for a period of time until it has recovered enough to maintain systemic circulation before it can be removed from extracorporeal circulation.