The development of extracorporeal circulation from a simple original idea to its actual clinical application in the 1950s took about 140 years. Prior to the 1950s, cardiac surgery was limited to closed heart procedures such as pericardial dissection and ligation of patent ductus arteriosus. This is because all surgical procedures have the basic requirements of “silence” and “no blood” in the operating field, and the heart itself is a “pump full of blood that keeps beating”, which becomes a “no-go area” for surgeons. The heart is a “no-go area” for surgeons.
How can we divert a large amount of high speed and high pressure blood flow out of the body while operating on the heart or large blood vessels, so that the surgical field can be “bloodless”; while the heart safely stops in diastole, the surgical field can be “quiet”; during the period when the heart stops pumping, the periphery can be perfused with oxygenated blood. During the period when the heart stops pumping, the peripheral organs are perfused with oxygenated blood without causing ischemic damage to the heart itself and the peripheral organs, which has been a major problem for surgeons for many years.
In 1939, Gibbon’s first artificial heart-lung machine was used in animals. In 1939, Gibbon’s first artificial heart-lung machine was successfully used in animal experiments; subsequently, more physicians experimented with various cross-circulation experiments. As a result, venous blood was drawn outside the body and oxygenated by an artificial lung (oxygenator), carbon dioxide was expelled, and an artificial heart (blood pump) was used to pump the oxygenated blood into the arteries, thus replacing the functions of the heart and lungs with an artificial heart-lung machine outside the body, which is called extracorporeal circulation (ECC). In the course of development, the names “cardiopulmonary bypass” (CPB) and “cardiopulmonary perfusion” (CPB) have also been used. The name of extracorporeal circulation machine can also be called artificial heart-lung machine accordingly.
Based on the research of many previous scholars, Gibbon successfully applied the concept of “extracorporeal circulation” for the first time in 1953 to repair an atrial septal defect in a girl under direct vision, which opened a new era of cardiac surgery and made the concept of “extracorporeal circulation” recognized by most physicians. The concept of “extracorporeal circulation” was accepted by most physicians. In 1957, Sealy, Brown and others combined the use of hypothermia with extracorporeal circulation.
From Lillehei’s use of human or animal (dog, monkey) lung “controlled circulation” for extracorporeal oxygenation, to the use of mechanical oxygenators for extracorporeal oxygenation; from a variety of primitive “blood film” type mechanical oxygenators to safer and more efficient From various primitive “blood film” mechanical oxygenators to safer and more efficient “bubble” and “membrane” oxygenators; from various primitive industrial “raft” blood pumps to “finger-pressure From the original industrial “raft” blood pumps, to “finger-pressure” and “roller” blood pumps, and then to centrifugal pumps and “pulsatile” blood pumps, the technology of extracorporeal circulation has been continuously improved and rapidly matured in less than 20 years, and safety has been continuously improved.
Since the early equipment and theory of extracorporeal circulation were not perfect enough to meet the clinical needs, many scholars found another way. Based on the principle that the body can survive a short period of complete circulatory arrest during hypothermia, Lewis and Swan successfully completed atrial septal defect repair in 1953 by completely blocking the circulation at deep hypothermia (below 16°C) in the whole body, causing an instant sensation. However, the shortcomings of deep hypothermic circulatory arrest surgery (short operation time and severe damage to various organs and organs due to deep hypothermia) were soon recognized. In 1958, Swan was the first to successfully combine hypothermia and extracorporeal circulation in cardiac surgery, obtaining more operating time while maximizing the physiological protection of the organs. Since then, “hypothermia” has gradually become an important part of extracorporeal circulation, and the mode of “extracorporeal circulation + hypothermia” has become a routine tool in cardiac surgery.
With the support of extracorporeal circulation technology, cardiac and vascular surgery also developed rapidly, and by the 1970s, almost all cardiac and macrovascular diseases, including heart transplantation, could be treated with safe and effective surgical procedures, truly entering the era of development of modern cardiac surgery.
Of course, no technology can be perfect, and the same is true for extracorporeal circulation technology. The potential pathological damage it may cause to the human body includes.
1. metabolic alterations: associated with poor tissue perfusion.
2. electrolyte imbalance: prominent is hypokalemia.
3. hemodilution and blood destruction: most prominently, destruction of red blood cells and coagulation factors, and coagulation mechanisms.
4. hypofunction of the lungs, kidneys and other organs.
5, systemic inflammatory-like response: complement activation, release of mediators of inflammatory response
Reflected at the level of systemic organs, it can be manifested as.
(i) cerebral and psychiatric complications.
1, cerebral hypoxia
2. epidural and extradural hematomas
3. cerebral embolism
(ii) Hypotension and low cardiac output syndrome
(C) postoperative coagulation mechanism disorders
(D) Acid-base balance and electrolyte disorders
(E) renal insufficiency
(vi) perfusion lung (ARDS)
However, the fear of extracorporeal circulation technology or extracorporeal circulation surgery is completely unnecessary.
Extracorporeal circulation is a mature and safe technique, and the procedures performed with it are now routine and reasonable. There is no need to overthink whether coronary artery bypass surgery is done under extracorporeal circulation or non-stop technique. Because coronary artery disease is often combined with many ischemic or infarct complications, such as ventricular wall tumor formation, septal perforation, mitral valve papillary muscle ischemia resulting in dysfunction, mitral regurgitation due to mitral valve insufficiency, and atrial or intraventricular thrombus formation. In these cases, coronary artery bypass is completed with the assistance of extracorporeal circulation and access to the cardiac chambers for the corresponding surgical operation, and the results are highly satisfactory. Even for simple coronary artery bypass, the quality and long-term results of the vascular anastomosis operation performed under extracorporeal circulation are far superior to non-stop, as confirmed by long years of bulk clinical and basic experiments in multiple centers in China and abroad.
After more than 50 years of development, the connotation and extension of extracorporeal circulation have changed a lot, and it has gradually evolved into a relatively independent specialty. At present, besides being mainly used for direct cardiac surgery, extracorporeal circulation is also widely used for respiratory and circulatory support treatment of other systemic diseases (including drug poisoning, carbon monoxide poisoning, severe shock, snake bite, pesticide or sleeping drug poisoning, etc.), major organ transplantation (heart, lung and liver transplantation), systemic thermotherapy for advanced tumors and local chemotherapy + thermotherapy for limb tumors, etc., and the resulting Circulatory assistance (ventricular assistant device (VAD)) and respiratory assistance (extracorporeal membrane oxygenation (ECMO)) play an important role in cardiopulmonary resuscitation of critically ill patients. Modern extracorporeal circulation technology has become a mature and safe treatment method that can safely replace the patient’s cardiopulmonary function for up to a month or even longer, gaining valuable time for the patient to obtain further treatment. The incidence of overall postoperative comorbidity after extracorporeal circulation has now been reduced to less than 3%.