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To repair the inside of a heart, a surgeon has to open it. But the heart cannot stop pumping, and the lungs cannot stop adding oxygen, for more than a few minutes without damage to the brain. John Gibbon spent about two decades on a way round that: a machine that takes over both jobs while the surgeon works. Here is his story, how the machine handles blood, a worked calculation using NCERT's cardiac output, and what you can learn from his persistence.
Who was John Gibbon?
The US National Library of Medicine's finding aid to his papers records that John Heysham Gibbon (1903 to 1973) was born in Philadelphia into a family of physicians, the fourth generation to practise. He studied at Princeton and earned his MD from Jefferson Medical College in 1927, where he later chaired the Department of Surgery.
The same record notes that the death of a young patient in 1931 first set him thinking about a device to bypass the heart and lungs. The people he told tried to talk him out of it. He kept going anyway.
What does a heart-lung machine have to do?
The NCERT Class 11 Biology chapter on Body Fluids and Circulation explains double circulation. The right side of the heart sends deoxygenated blood to the lungs; the left side sends oxygenated blood to the body. A heart-lung machine replaces both steps at once.
Collect blood returning to the heart before it enters it.
Oxygenate it and remove carbon dioxide, which is the lungs' job.
Pump it back into an artery at the right pressure and flow, which is the heart's job.
Each step is hard. Blood clots on foreign surfaces, red cells break if handled roughly, and the flow has to match what the body needs.
How did Gibbon's machine develop?
The NLM record states that in 1935 his prototype kept a cat alive for 26 minutes. In 1937 he reported his early experiments in the Archives of Surgery, in a paper titled Artificial maintenance of circulation during experimental occlusion of pulmonary artery. War service in the China-Burma-India theatre then interrupted the work.
In the 1950s he resumed with machines built by IBM. The new oxygenator let blood run down thin sheets of film, rather than an earlier whirling method that could damage blood cells. With it, twelve dogs survived more than an hour of heart surgery.
What happened on 6 May 1953?
A 2015 review of cardiopulmonary bypass in the Brazilian Journal of Cardiovascular Surgery dates the landmark operation to 6 May 1953, when Gibbon repaired an atrial septal defect, a hole in the wall between the heart's upper chambers. The patient was Cecelia Bavolek, and the NLM record notes that the machine fully supported her heart and lung function for more than half of the operation.
The citation for his 1968 Lasker Award calls this "the first successful open-heart operation in the world using a heart-lung machine on a human patient", after "18 long years of experimental engineering and animal work". Counting from the 1935 cat experiment to 1953 gives exactly those 18 years.
Worked example: how much blood does the machine handle?
NCERT gives a stroke volume of about 70 mL and a heart rate of 72 beats a minute.
Cardiac output. 70 × 72 = 5,040 mL per minute, about 5 L, matching NCERT's average of 5,000 mL.
A sample 30-minute bypass. 5 × 30 = 150 L of blood must be oxygenated and pumped.
Per second. 5,000 / 60 = 83 mL every second, without clotting or crushing cells.
These are sample figures for a resting adult, not numbers from Gibbon's operation. They show why the oxygenator design took so long to get right.
What mistakes do students make with cardiac output?
Mixing units. Stroke volume in mL times beats per minute gives mL per minute. Convert to litres only at the end.
Thinking each ventricle pumps half. Each ventricle pumps the cardiac output; that is how NCERT defines it.
Forgetting the lungs. Bypassing the heart alone is not enough. Blood also has to pick up oxygen.
Our post on body fluids and circulation covers the full chapter, and the story of how circulation was first understood is in William Harvey and the circulation of blood. For the valves that later went into opened hearts, read about M. S. Valiathan and the Chitra heart valve.
If you are not sure where to begin with the circulation chapter, Fermi's AI tutor can work out what you already know and build a plan for the session.
What can a student learn from Gibbon's way of working?
Hold one problem for a long time. He kept one goal from the 1930s to 1953, through a war.
Test in steps. A cat for minutes, then dogs for an hour, then a person.
Bring in engineers. The IBM partnership gave him the precision a surgeon alone could not build.
Next step: calculate cardiac output for a stroke volume of 80 mL at 75 beats a minute, then work out how much blood a 45-minute bypass would handle.
