What is Cardiopulmonary Bypass?
All the deoxygenated blood in your body returns to the right atrium of your heart. Normally, it is passed from here to the right ventricle and then into the lungs, where oxygen is added and carbon dioxide is removed. From the lungs, the blood travels to the left atrium and then into the left ventricle which pumps it into the arteries.
As the name suggests, Cardiopulmonary bypass is a technique of intercepting vemous blood as it enters the right atrium and diverting it into an excorporeal circuit (the Heart/Lung Machine), where oxygen is added and carbon dioxide removed before the blood is returned to the patients arterial system.