Heart-lung machine

Cardiopulmonary bypass
Intervention
A heart–lung machine (upper right) in a coronary artery bypass surgery.
ICD-9-CM	39.61
MeSH	D002318
OPS-301 code	14
Other codes	22570829
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Cardiopulmonary bypass (CPB) is a technique that temporarily takes over the function of the heart and lungs during surgery, maintaining the circulation of blood and the oxygen content of the patient's body. The CPB pump itself is often referred to as a heart–lung machine or "the pump". Cardiopulmonary bypass pumps are operated by perfusionists. CPB is a form of extracorporeal circulation. Extracorporeal membrane oxygenation is generally used for longer-term tretament.

Cardiopulmonary bypass is commonly used in coronary bypass heart surgery because of the difficulty of operating on the beating heart. Operations requiring the opening of the chambers of the heart require the use of CPB to support the circulation during that period. The machine pumps the blood, and, using an oxygenator, allows red blood cells to pick up oxygen, as well as allowing carbon dioxide levels to decrease. This mimics the function of the heart and the lungs, respectively.

CPB can be used for the induction of total body hypothermia, a state in which the body can be maintained for up to 45 minutes without perfusion (blood flow). If blood flow is stopped at normal body temperature, permanent brain damage normally occurs in three to four minutes — death may follow shortly afterward. Similarly, CPB can be used to rewarm individuals suffering from hypothermia.

Extracorporeal membrane oxygenation (ECMO) is a form of CPB sometimes used as life-support for newborns with serious birth defects, or to oxygenate and maintain recipients for organ transplantation until new organs can be found.