One day in 1972, Dr. Henry Heimlich, a thoracic surgeon, was reading an article in the New York Times Magazine about accidental deaths and noted that choking was number six on the list. About 3,000 people died each year from choking. Being a thoracic surgeon, Dr. Heimlich had a complete understanding of the throat and its swallowing mechanisms, so he dug into the medical journals about choking interventions. He found that the main recommendation was to pound the choking victim on the back, which research had found ineffective because the pounding tended to drive the obstruction further down the airway. Another solution (only for medical professionals) was to slit open the trachea with a knife. So, if someone was choking, there was nothing anyone could do that was effective — they just died.

Dr. Heimlich dug into the problem and began experimenting in his lab on anesthetized dogs. He inserted a balloon, which served to simulate an obstruction, in the dogs’ airways and experimented on how he could cause the lungs to expel enough air to eject the balloon. Through trial and error, he found that pushing on the abdomen just below the diaphragm caused a great deal of air to be expelled.

Next, he had to figure out how to apply such pressure on a human choking victim. Here’s how Dr. Heimlich described figuring out his technique in an essay he authored:

“After many tests and trials, it became obvious that the best technique was to stand behind the victim and reach around the choking person’s waist with both arms. Make a fist. Place the thumb side of your fist below the rib cage, just above the belly button, grasp the fist with the other hand and press it the fist inward and upward. Perform it firmly and smoothly and repeat until the choking object is dislodged from the airway. In most reports the object flies out of the mouth and sometimes hits the wall or even the ceiling.

I called this method ‘sub-diaphragmatic pressure.’ It can be mastered in one minute from a poster. To learn it, you do not even need to take a first-aid course.“

He published his research in a medical journal in 1974 in a paper titled “Pop Goes the Cafe Coronary” (the slang term at the time for choking on food in a restaurant was a “cafe coronary”). The technique was reported on by a major newspaper and then by newspapers across the country. As people were saved from the technique, those stories made it into the news and knowledge of how to save a choking victim spread.

Eventually, the diaphram compressing technique became known as the “Heimlich Maneuver.” The Heimlich Maneuver has saved an estimated 50,000 lives since its discovery and continues to save thousands each year.

Even though he developed the Heimlich Maneuver, Dr. Heimlich didn’t have occassion to use it until he was 96 years old. While eating dinner in his nursing home, Dr. Heimlich noticed an 87-year old resident choking on a piece of meat. He sprung into action, performed his eponymous technique and saved the woman’s life. “It was very gratifying,” he told The Guardian at the time. “That moment was very important to me. I knew about all the lives my manoeuvre has saved over the years and I have demonstrated it so many times but here, for the first time, was someone sitting right next to me who was about to die.”

Dr. Heimlich died seven months later.