December 19, 2022 Author : José Roquette Extracorporeal circulation is a technique that replaces the heart and lungs in: Open-heart surgeries , for example for repairing injuries or birth defects, replacing valves or correcting defects in its closing or opening, and myocardial revascularization; Heart transplants . In many of these surgeries it is necessary that the blood does not pass through the heart, but it is still necessary that oxygenated blood reach all the tissues and organs of the body. For this to be achieved, a cardiopulmonary bypass is performed, that is, the functions of the heart and lungs are “bypassed”, becoming performed by an external equipment called an extracorporeal circuit. Normal circulation and extracorporeal circulation Under normal circumstances : Venous blood enters the right atrium of the heart, passes into the right ventricle and then travels to the small circulation through the pulmonary artery to the lungs to be oxygenated; Once oxygenated, blood returns through the pulmonary vein to the left atrium of the heart, travels to the left ventricle, and is then pumped through the aorta into the greater circulation. In extracorporeal circulation : Venous blood is diverted as it enters the right atrium, heading to the extracorporeal circulation circuit; Once oxygenated in this device, the blood returns to the main circulation, normally in the aorta, to be distributed throughout the body. The extracorporeal oxygenator To carry out the functions of the heart and lungs according to the needs of different complexity and duration surgeries, the device has several components , the main ones being: System that diverts blood before reaching the right atrium; Reservoir / oxygenator, where the blood goes and where carbon dioxide is removed and oxygen added; Temperature controller, which allows to change the blood temperature before re-entering the body; Pumps and filters to ensure blood movement and eliminate eventual clots; System that ensures the return of blood to the main circulation. Without the extracorporeal circuit, cardiac surgery would not be the same today Without the cardiopulmonary bypass technique, i t would not be possible to perform many heart surgeries , which are often very long and complex. Since they were conceived, the technical evolution of extracorporeal oxygenators has been substantial and the main complications that initially occurred are now just a memory. There are many people to highlight in this technique history since the possibility of artificial blood oxygenation was thought of for the first time in the 17th century, by Robert Hooke from his studies on animals, passing through the discovery and use of heparin (anticoagulant) in medicine in 1935 and extracorporeal oxygenators introduced in cardiac surgery in the 20th century. Cardiac surgery developed mainly from the 1940s onwards . In the early years it was still limited, as there were few procedures that could be performed safely while maintaining cardiopulmonary circulation. John Gibbon in 1953 invented cardiopulmonary bypass and performed the first intracardiac surgery with extracorporeal circulation. C. Walton Lillehei , 'father of open-heart surgery', also pioneered cardiac surgery with extracorporeal oxygenation, but without using artificial equipment. In 1954 , his team corrected a cardiac septal defect in an 11-year-old boy, using his anesthetized father as an oxygenator . The boy's venous blood flow was diverted to the father's femoral vein and lungs, where it was oxygenated, then returned to the patient's body in the carotid artery. Less than 10 years later, on April 5, 1962 , the first cardiac surgery with cardiopulmonary bypass was performed in Portugal , at Hospital de Santa Marta by Prof. Machado Macedo and his team. Sources C. Walton Lillehei, the "Father of open heart surgery". Circulation 1999;100(13):1364-5. doi: 10.1161/01.cir.100.13.1364. Lim MW. The history of extracorporeal oxygenators. Anaesthesia 2006;61:984-95. doi: 10.1111/j.1365-2044.2006.04781.x. Conheça a equipa de cirurgia cardíaca da rede Hospital da Luz e faça a marcação da sua consulta The content published in the Health Guide is intended for the general public and is provided for informational and educational purposes only. It does not replace individual medical assessment, diagnosis, or personalized clinical advice from a qualified healthcare professional. The content is produced or reviewed by physicians and other healthcare professionals at Hospital da Luz and is based on the knowledge available at the time of publication or the most recent update, as indicated at the beginning of each item.
