2, it is the blood from the body to the outside of the body, through the membrane lung oxygenation, and then the blood pump or extracorporeal circulation machine blood into the body, so that the heart and lungs to get a rest, for the recovery of cardiopulmonary function to buy time. This technique is more commonly used in heart transplantation and extracorporeal circulation. It is currently used in the resuscitation of critically ill patients with new coronavirus pneumonia.