# 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. - **Patent:** US 2702035 - **Original title:** Oxygenating unit for extracorporeal circulation devices - **Owner:** JEFFERSON MEDICAL COLLEGE - **Granted:** 1955 - **Status:** Public domain (expired) - **Times cited:** 4 - **Field:** biotech, mechanical ## What it does 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 does NOT 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. ## Real-world examples 1. Early heart-lung bypass machines used in the 1950s 2. Experimental extracorporeal circulation circuits ## 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. ## Frequently asked questions ### What does How the First Heart-Lung Machine Oxygenated Blood cover? A 1955 invention that allowed surgeons to oxygenate a patient's blood outside the body, enabling the first successful open-heart surgeries. ### Who owns patent US 2702035? JEFFERSON MEDICAL COLLEGE owns this patent, granted in 1955. ### When does this patent expire? This patent has expired and is now in the public domain — anyone can use the invention freely. ### What is patent US 2702035 cited by? This patent has been cited by 4 later patents that build on its ideas. ### What problem does this patent solve? 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. ### What does this patent NOT cover? Does not cover membrane-based oxygenators that use synthetic materials instead of direct gas-to-blood contact. **Full plain-English explainer:** https://patentbrief.org/patent/us/2702035/heart-lung-machine-gibbon **Original patent:** https://patents.google.com/patent/US2702035 --- _Source: PatentBrief — https://patentbrief.org. Patent facts are from public records; the plain-English explanation is PatentBrief's._ ## Related patents Semantically similar inventions in the PatentBrief corpus: - [How the Iron Lung Artificial Respirator Works](https://patentbrief.org/patent/us/1906844/iron-lung-respirator-drinker) — A 1933 patent for a mechanical respirator that uses external air pressure changes to force a patient's lungs to expand and contract. - [How Jarvik's Artificial Heart Uses Electric Motors to Pump Blood](https://patentbrief.org/patent/us/4173796/jarvik-artificial-heart) — A 1977 invention by Robert Jarvik that uses a reversible electric motor to power a hydraulic pump, enabling artificial hearts to mimic the natural pumping action of a human heart. - [How Dr. Forrest Bird's Mechanical Respirator Controls Patient Breathing](https://patentbrief.org/patent/us/3191596/bird-respirator-ventilator) — A 1965 patent describing a mechanical ventilator that automatically switches between inhaling and exhaling based on pressure levels in a patient's airway. - [Leonarde Keeler's Early Mechanical Blood Pressure Recorder](https://patentbrief.org/patent/us/1788434/polygraph-lie-detector-keeler) — A 1925 invention by Leonarde Keeler designed to mechanically record a patient's arterial blood pressure over time. - [How the Aqua-Lung Scuba Regulator Works](https://patentbrief.org/patent/us/2485039/aqualung-scuba-cousteau-gagnan) — The foundational 1947 patent by Jacques Cousteau and Emile Gagnan for the automatic demand regulator that allows divers to breathe compressed air underwater.