The diagram shows how ECMO works. Once in place, the tubes are connected to the ECMO circuit and then the machine is turned on. The patient’s blood flows out through the tube and may look very dark because it contains very little oxygen. A pump pushes the blood through an artificial membrane lung, where oxygen is added and carbon dioxide is removed. The blood is then returned to the patient. A steady amount of blood (called the flow rate) is pushed through the ECMO machine every minute. As the patient improves, the amount of oxygen added is decreased.
The main advantage of ECMO, is that it can keep up the supply of oxygen to the body while resting the lungs.
With conventional treatment the ventilator is adjusted to make up for the patient’s reduced lung function, increasing the amount of oxygen blown into the lungs by the ventilator and increasing the pressure at which it is delivered. This forces more oxygen into the lungs. It is now known that high-pressure ventilation with large amounts of oxygen can actually cause further injury to the lungs and can prevent them from recovering.
Using ECMO, the pressure and oxygen concentration used to ventilate the lungs can be greatly reduced to safer levels.