Extracorporeal membrane oxygenation (ECMO) or extra corporeal membrane life support (ECLS) is a tool that replaces the function of the lungs and heart when they can no longer function normally, even with medication or a ventilator, until the heart and lungs can be treated so they resume normal function. The ECMO will pump blood instead of the heart and will exchange oxygen instead of the lungs. The ECMO removes blood from the body and moves it through a pump (that functions like the heart) and then it is filtered through a membrane oxygenator that adds oxygen and removes carbon dioxide (functioning like the lungs). The blood is then returned to the body. The mechanism is same as that of a cardiopulmonary bypass machine. A doctor will place the cannula into a large vein and a large artery at the leg or neck.