TLDR: Cardiopulmonary bypass (CPB) is a technique used during surgery to temporarily take over the function of the heart and lungs. It uses a machine called a heart-lung machine to circulate and oxygenate the blood while the surgeon works on the heart. CPB is commonly used in heart surgeries and other procedures that require the heart to be stopped or the chambers of the heart to be opened. It has risks and complications, but it has been an important advancement in the field of cardiac surgery.

Cardiopulmonary bypass (CPB) is a technique used during surgery to temporarily take over the function of the heart and lungs. It involves using a machine called a heart-lung machine, also known as "the pump," to circulate and oxygenate the blood while the surgeon works on the heart. The heart-lung machine is operated by perfusionists, who are specially trained healthcare professionals.

During CPB, the surgeon places a cannula (a small tube) in a vein or artery to withdraw blood from the body. The blood is then filtered, cooled or warmed, and oxygenated before being returned to the body by a mechanical pump. This allows the surgeon to work in a bloodless surgical field and maintain perfusion to other organs and tissues.

CPB is commonly used in heart surgeries, such as coronary artery bypass grafting (CABG) and cardiac valve repair or replacement. It is also used in procedures that require the opening of the chambers of the heart, such as mitral valve repair or replacement. CPB allows the surgical team to oxygenate and circulate the patient's blood, which is necessary for the surgeon to operate on the heart.

There are risks and complications associated with CPB, such as protamine reactions, thrombosis, aortic dissection, gas embolism, and dislodging of cannulas. CPB can also contribute to immediate cognitive decline and activate the coagulation cascade, leading to hemolysis and coagulopathies. However, CPB has been a significant advancement in the field of cardiac surgery and has allowed for complex heart surgeries to be performed.

In summary, cardiopulmonary bypass is a technique used during surgery to temporarily take over the function of the heart and lungs. It involves using a heart-lung machine to circulate and oxygenate the blood while the surgeon works on the heart. CPB is commonly used in heart surgeries and other procedures that require the heart to be stopped or the chambers of the heart to be opened. While there are risks and complications associated with CPB, it has been an important advancement in the field of cardiac surgery.