What is an iron lung? How it worked and its influence today

In the mid-20th century, community spaces like swimming pools and sporting events became a source of anxiety for parents who were frightened by the rampant spread of poliovirus. Their concerns weren’t unfounded. Polio is a debilitating disease that invades the body’s nervous system, and prior to the invention of the polio vaccine, it claimed the lives of hundreds of thousands of people globally every year.
The iron lung, conceptualized in the late 1920s, was most notably the first line of defense against polio during the epidemics that occurred between 1948 to 1955. The device saved the lives of thousands of patients (primarily children) whose lungs became paralyzed or weakened by polio, helping them to breathe, per Harvard Medical School.
The iron lung has disappeared from modern medicine, but its legacy remains. Here’s why the device fundamentally changed how healthcare providers today tend to patients facing many different kinds of life-threatening conditions.
What is the iron lung?
The iron lung was a large, cylindrical unit (measuring up to six feet in length) that functioned as a respirator to help patients who couldn’t breathe on their own. Patients would lay down with their head resting outside the chamber, with the device enclosed around their body, per the U.S. Centers for Disease Control and Prevention. The iron lung used negative pressure ventilation (NPV), which “mimics natural breathing by creating negative pressure around the chest, causing the lungs to expand and pull in air,” explains Dr. Jim Mendez, a clinical associate professor of nursing at Villanova University.
For many polio patients, the iron lung was a bridge for survival, says Dr. Daniel Salerno, a pulmonary and critical care physician, and faculty at Temple University. Patients were often housed together in large wards. While many people only depended on the iron lung for one to two weeks until they recovered, approximately one in 200 polio patients experienced a more permanent paralysis of their respiratory muscles. These patients depended on the iron lung for years, and potentially for the rest of their lives, Salerno says.
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Are iron lungs still used today?
After 1955, when the first polio vaccine became licensed in the U.S., polio cases dwindled, and the need for the iron lung rapidly declined, says Mendez.
Paul Alexander, one of the last surviving people in America to live in an iron lung, passed away in early 2024 at the age of 78. After contracting polio in 1952 as a child, Alexander relied on the iron lung throughout his life. Despite the immense physical challenges he endured, Alexander went on to complete further education, practice law for 30 years, and write an autobiography. He shared his remarkable story on TikTok, educating followers about his life in the iron lung, and bringing awareness to the millions of children across the world that still aren’t currently vaccinated against polio.
Today, the effort to eradicate polio is a global one. Since 1988, wild poliovirus cases have decreased by more than 99%, but the disease is still considered endemic in two countries, Pakistan and Afghanistan. International agencies have made outstanding progress in administering polio vaccinations, and according to the World Health Organization, more than 20 million people who would have been paralyzed by polio have the ability to walk today.
More:Francis Ford Coppola, who survived polio, has harsh words for vaccine detractors
What has replaced the iron lung?
At the time of its invention, the iron lung was widely regarded as a cutting-edge mechanical ventilator. Despite its limitations, “the device spurred innovations in ventilator design and critical care, ultimately leading to the development of positive pressure ventilators and other life-support systems used in intensive care units today,” says Mendez.
Whereas the iron lung used NPV to facilitate airflow in patients, today’s ventilators use positive pressure ventilation (PPV), Mendez notes. The iron lung was less invasive than modern technology, but it would be far less effective in treating acute or respiratory conditions that require high-pressure support, like pneumonia, COVID-19 and emphysema, he notes.
“Moreover, (the iron lung) highlighted the importance of managing respiratory failure, which has become a cornerstone of critical care medicine,” says Mendez. “In a great way, these iron lung wards were the precursor of medical ICUs,” adds Salerno. ICUs have the ability to tend to patients facing a variety of conditions, from gastrointestinal bleeding to renal failure, but their origin is still deeply connected to pulmonary medicine, he says.
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