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Cardiopulmonary Bypass and the Heart-Lung Machine

Cardiopulmonary Bypass and the Heart-Lung Machine


The Heart-Lung Machine is needed to perform any open-heart surgery: for instance, conventional CABG (Coronary Artery Bypass Graft), valve repair/replacement, aortic surgery, congenital defects etc., and rarely some airway operations.

The Heart-Lung Machine has three main components: an oxygenator, a pump and a heater-cooler. Its job is to temporarily replace the functions of the heart and lungs, whilst the surgeon operates on the heart. In a nutshell, blood is drained from the body into the heart-lung machine, bypassing the heart and the lungs, and then is pumped back to the body. Hence the term ‘cardiopulmonary bypass’ or ‘CPB’.

NOTE: Bypass’, one name, two meanings – the word ‘bypass’ is used in the context of CABG and CPB, but they have different meanings:
* Cardiopulmonary bypass (CPB) is when the Heart-Lung machine is used to make blood bypass the heart and lungs.
* Coronary artery bypass graft (CABG) is when a graft (vein or artery) is used to bypass a coronary artery obstruction.

To establish CPB, first the blood is thinned with a drug called Heparin. Routinely, big pipes (cannulae) are used to drain the oxygen-poor blood from the right atrium or cardiac veins (superior and inferior cava veins).  Another cannula is inserted in the aorta to return oxygen-rich blood processed by the Heart-Lung machine. (In some circumstances, vessels from the neck or groin are used to establish oxygenated blood return to the body)

During CPB, the oxygenator exchange gases (adds oxygen and removes carbon dioxide), the heater-cooler controls the blood/body temperature, and the pump returns oxygen-rich blood back to the body.

Once the cardiac problem is fixed, the heart is fed/perfused with blood and resumes beating. Then the Heart-Lung machine is weaned off and the heart takes over the circulation again. Cannulae are removed and blood thinning is reversed with a drug called Protamine.

Associated Risks

CPB is one of the cornerstones in cardiac surgery. It is performed routinely with excellent results, allowing surgeons to perform complex operations with low mortality.

NOTE: CPB safety. All circuitry (cannulae, oxygenator, and tubes) is disposable and single use only. The pump and the heater-cooler do not contact patient’s blood directly. Filters are used in the circuit to prevent stroke.

Please refer to the link.

Please speak to Dr. Provenzano regarding your individual circumstances and any questions or doubts you may have.

For an appointment or seeking a second opinion with Dr Provenzano, please contact:

Gold Coast Private Specialist Suites 14 Hill Street, Southport

P: (07) 5699 8258   F: (07) 5676 6784

Dr Sylvio Provenzano


Dr Sylvio Provenzano is an exam-qualified Cardiothoracic Surgeon by the Royal Australasian College of Surgeons (RACS). He specialises in cardiac, thoracic and congenital cardiac surgery.

Opening Hours

Gold Coast Private Specialist Suites

14 Hill Street, Southport 4215
9:00 – 16:00
Phone: (07) 5699 8258
Fax: (07) 5676 6784
PO Box 809, Southport BC, Qld 4215