Heart-Lung Machine / Cardiopulmonary Bypass

Heart-Lung machines temporarily do the work of the heart and lungs allowing surgeons to operate on the heart or lungs. Despite the sci-fi nature, it was a husband-wife garage invention.

Background

In 1931, surgeon John Gibbon lost a patient he felt sure would have lived if he could temporarily keep blood circulating and oxygenated. He worked with his lab assistant, Mary Hopkinson, to develop a heart-lung machine. More than the machine progressed, and John and Mary eventually married.

The Gibbon’s experimented on cats. By 1935, they were able to keep a cat alive for 20 minutes while their machine replaced heart and lung function. However, the machine damaged blood cells and virtually no cat lived longer than 23 days after surgery.

Gibbons’ machine relied largely on a blood oxygenator. This was a series of rollers, developed in 1885 by von Frey and Gruber, that thinned out blood and exposed it with oxygen. The rollers mimicked the surface area of the lungs. Additionally, it was a challenge to find a pump as strong as human hearts. Patients’ blood must be saturated with heparin to prevent coagulation, which would gunk up the machine.

By 1945, Gibbon included other researchers and expanded their research to dogs. They found that by adding filters to remove blood clots and applying suction to prevent air from entering the bloodstream survival rates dramatically increased.

On May 6, 1953, Gibbon and his team decided their machine was ready for use on people. Gibbon operated on Cecelia Bavolek, bypassing her heart and lungs with his machine for 45 minutes. She lived and fully recovered from the operation. Unfortunately, Gibbon’s next four patients died and he abandoned heart surgery.

Walton Lillebei

Walton Lillebei picked up where Gibbons’ left off. He tried a radically different approach, connecting one person to another whose heart and lungs would do the work for two. Typically, a child would be connected to one of their parents. Lillebei also invented the bubble oxygenator, replacing the rollers used in Gibbons’ machine. Finally, the heart-lung machine was reliable.

Despite the success, there was one major problem: the heart kept beating during the use of the machine. This caused a literal bloody mess, making it difficult for surgeons to see. Returning to animal research, they found it was possible to stop a heart while a patient was connected to the machine and restart it later. However, the lack of blood in the heart caused tissue damage. Surgeons operated with beating hearts until the 1980s when researchers at St. Thomas Hospital found that cooling the heart below 28°C (82°F) and treating it with a combination of drugs kept the heart healthy and intact. Today, this technique is used for extended operations where a heart must be stopped and also to transport hearts for transplanting.