How the iron lung paved the way for the modern-day intensive care unit (2025)

With the passing of iron lung patient Paul Alexander, a look back at how the device paved the way for subsequent life-saving medical innovations.

The device enabled hundreds of individuals to survive polio, a viral infection that attacks the body and can lead to paralysis and death within a matter of hours as breathing muscles become immobilised. However, with the iron lung, a massive machine that encases patients and provides air pressure to help the impacted individual's paralysed lungs function, life could continue for years.

Such was the case for Paul Alexander, known globally as "The Man in the Iron Lung", who died this week at the age of 78. Alexander contracted polio in 1952, when he was just six years old, leaving him paralysed from the neck down. Although he made tremendous progress learning to breathe on his own for short periods of time – he attended school and practised as a lawyer – Alexander lived the remainder of his life relying on the iron lung to survive.

Developed in 1927 by a faculty member from the Harvard T.H. Chan School of Public Health, industrial hygienist Philip Drinker, the iron lung was first used to save the life of a child in 1928. It swiftly became a fixture in polio wards during the polio outbreaks of the subsequent decades, particularlyfrom 1948 until the vaccine was developed in 1955. And its creation paved the way for many subsequent medical innovations.

How the iron lung works

During the early 20th century, polio outbreaks were occurring around the world, spread via contaminated food and water. And up until the 1955 vaccine, the iron lung was the primary mode of treatment for severe cases and was considered state-of-the-art technology.

Some patients spent just a short time in the iron lung, perhaps weeks or months until they were able to regain chest strength and breath independently again. But for patients whose chest muscles were permanently paralysed, the iron lung remained the key to survival.

While it was a lifesaving development, there were also many limitations with the iron lung for both patients and medical providers. Many patients felt trapped inside of the device, and it was difficult for doctors to access a patient's body and provide treatment to someone encased in the iron lung. But the invention, nevertheless, laid the foundation for many future medical advances.

"That concept of supporting an organ, such as the lungs, became the centrepiece of modern critical care," says Wunsch.

Subsequent medical innovations

The development of the iron lung is often seen as a milestone in the development of mechanical ventilators, which were not widely used prior to the polio outbreak.

"Ventilation science came into brighter lighting as a result of the iron lung," says Peter Gay, a pulmonary, critical care and sleep physician with the Mayo Clinic. "The physiology of gas exchange was better understood once they mechanised moving air in and out of the body."

One of the early ventilator developments was pioneered by Bjorn Aage Ibsen. In 1953, Ibsen proposed using "positive pressure" ventilation. In contrast to the iron lung, which relied on negative pressure ventilation that suctioned air into a patient's lungs, positive pressure ventilation would push air into the lungs by hand, without the aid of machine.

Subsequent ventilator developments, which blow air into the lungs, were more portable than the iron lung – and far less cumbersome and invasive. This type of positive pressure approach would later be used routinely in the operating room by anesthesiologists.

While ventilator technology has evolved dramatically over the years and expanded, it remains very similar in concept to what was developed early on. Modern ventilators that sit at a patient's bedside delivering positive pressure in an intensive care unit can be traced back to the polio epidemic.

The development of iron lung technology "created the concept that you could put a whole lot of people into a room and support them with this life-saving gas exchange that they needed," adds Gay. Thus, the idea of an Intensive Care Unit (ICU) was born.

According to the Respiratory Care Journal, "The first ICUs were set up to manage in some cases dozens of patients, of all ages, requiring negative-pressure ventilation because of poliomyelitis [polio]."

"You had these units with all of these polio patients using the iron lung, and that's where the idea of intensive care units really took off," continues Gay. "That's why anesthesiologists initially became the critical care experts. Because anesthesiologists were largely the first to administer this type of intensive care."

More like this:

Wunsch concurs, pointing out that "creating respiratory centres for the care of polio patients supported by iron lungs helped cement the idea that complex care of patients required a dedicated area, with highly skilled caregivers. This concept is also very much at the heart of modern ICUs."

Equally important, the ability to support a patient’s respiratory system more effectively has allowed for better treatment of many other critical illnesses.

"So often, when people have critical illness, respiratory failure accompanies the illness – when patients are septic, or have pneumonia or infections – the respiratory system has to be supported in order for any other organ failure to be recovered," adds Gay.

Ventilators and the coronavirus pandemic

Polio was feared around the world at the peak of its epidemic. The disease left hundreds of thousands of children paralysed each year. The iron lung helped save many of them: In the United States alone, it was used by 1,200 people in 1959.

Fast-forward to late 2019 and early 2020, and the world one again found itself grappling with a frightening disease. During the Covid-19 pandemic peak, ventilation was once again at the forefront of treatment. Most recently, a team of engineers and doctors has invented the modern version of the iron lung – technology that serves as a breathing aid for patients with Covid-19.

The new device, which is still in development and has not yet been brought to market, is named Exovent NPV. It is also a negative pressure ventilator, and works by decreasing "the pressure outside the body to allow lung tissue to expand and function in a way that resembles normal breathing," according to the Institution of Mechanical Engineers. There is also hope that the device may be used to help with conditions such as pneumonia. The Exovent is merely the latest example of a medical innovation that can trace its roots back to the invention of the iron lung.

--

If you liked this story, sign up for The Essential List newsletter – a handpicked selection of features, videos and can't-miss news delivered to your inbox every Friday.