Bypass Machine

Become a part of the BMET community & join our brand new forums to connect!

A bypass machine, also known as a cardiopulmonary bypass (CPB) machine or heart-lung machine, is a sophisticated medical device used during open-heart surgery to temporarily take over the functions of the heart and lungs. It facilitates the circulation of blood and oxygen throughout the body while the heart is stopped for surgical procedures. Let’s explore its technical and functional details, purpose in hospitals, and a bit of its history.

Technical and Functional Details:

1. Components:

  • Pump: The core component of the bypass machine is a pump that propels blood through the patient’s body.
  • Oxygenator: The oxygenator is responsible for adding oxygen to the blood and removing carbon dioxide, simulating the gas exchange function of the lungs.
  • Heat Exchanger: The heat exchanger helps regulate the temperature of the blood, maintaining it within the physiological range.
  • Filters and Monitoring Devices: Various filters and monitoring devices are integrated into the bypass machine to ensure the quality and safety of the blood flow.

2. Cannulas and Tubing:

  • Cannulas are inserted into the patient’s blood vessels to divert blood flow away from the heart and lungs and into the bypass machine.
  • Tubing connects the cannulas to the bypass machine, creating a closed circuit through which blood flows.

3. Anticoagulation:

  • To prevent blood clotting within the bypass machine, anticoagulants such as heparin are administered to the patient before the procedure.

4. Control Systems:

  • Advanced control systems monitor various parameters such as blood pressure, oxygen saturation, and temperature, allowing medical staff to adjust settings as needed during the procedure.

Purpose in Hospitals:

  1. Facilitation of Open-Heart Surgery:
  • The primary purpose of a bypass machine is to maintain blood circulation and oxygenation during open-heart surgery when the heart must be stopped to perform surgical procedures on the heart or major blood vessels.
  1. Temporary Support for Heart and Lungs:
  • The bypass machine temporarily takes over the functions of the heart and lungs, allowing surgeons to operate on a still and bloodless surgical field.
  1. Protection of Vital Organs:
  • By providing oxygenated blood to vital organs such as the brain and kidneys, the bypass machine helps prevent organ damage and dysfunction during the surgical procedure.
  1. Extended Surgical Procedures:
  • Bypass machines enable surgeons to perform complex and lengthy cardiac procedures that require extended periods of time with the heart stopped.


  • The development of the first successful heart-lung machine is credited to Dr. John Gibbon, who performed the first open-heart surgery using a bypass machine in 1953.
  • Dr. Gibbon’s groundbreaking work laid the foundation for modern cardiac surgery and revolutionized the treatment of cardiovascular diseases.
  • Since then, significant advancements have been made in bypass machine technology, leading to improved safety, efficiency, and patient outcomes in open-heart surgery.

The bypass machine remains a critical tool in cardiac surgery, enabling surgeons to perform intricate procedures with precision while minimizing the risk to patients. Its evolution reflects the relentless pursuit of innovation and excellence in the field of cardiovascular medicine.