How the First Heart-Lung Machine Oxygenated Blood

A 1955 invention that allowed surgeons to oxygenate a patient's blood outside the body, enabling the first successful open-heart surgeries.

What it covers

This device creates a thin, continuous film of blood inside a rotating cylinder to expose it to oxygen. By spinning the outer shell, centrifugal force spreads the blood into a wide, thin layer, which maximizes the surface area for gas exchange. A stationary inner cylinder helps direct a counter-current flow of oxygen upward while the blood flows downward, mimicking the natural gas exchange process in human lungs. A vertical jet assembly allows doctors to precisely control where the blood is introduced into this rotating system.

What it doesn't cover

• —Does not cover membrane-based oxygenators that use synthetic materials instead of direct gas-to-blood contact.
• —Does not cover systems that oxygenate blood through bubbling or foam-based methods.
• —Does not cover the pump mechanisms or the surgical procedures themselves, only the specific oxygenating chamber assembly.

The clever bit

The invention uses a rotating cylinder to turn gravity and centrifugal force into a tool for spreading blood into a precise, thin film, solving the problem of how to oxygenate blood quickly without damaging the delicate blood cells.

Why it matters

This patent represents the core technology behind the heart-lung machine developed by Dr. John Gibbon. It was the critical breakthrough that allowed surgeons to stop a patient's heart and lungs during surgery without causing brain damage from oxygen deprivation. It effectively launched the field of modern cardiac surgery.

Real-world examples

• 1.Early heart-lung bypass machines used in the 1950s
• 2.Experimental extracorporeal circulation circuits