During the mid-20th century, places like swimming pools and sports events sparked anxiety among parents concerned about the widespread poliovirus. Their fears were justified, as polio is a serious illness that attacks the nervous system, leading to the deaths of hundreds of thousands worldwide each year before a vaccine was available.

Developed in the late 1920s, the iron lung was crucial in combating polio during epidemics from 1948 to 1955. This life-saving device helped thousands of patients, particularly children, whose lungs were compromised by the virus, aiding them in breathing, as noted by Harvard Medical School.

Though the iron lung is no longer used in modern medicine, its impact on healthcare endures. Here’s how it transformed the care provided to patients with various life-threatening ailments.

What is the iron lung?

The iron lung is a large cylindrical machine (up to six feet long) that worked as a respirator for patients unable to breathe independently. Patients lay inside, with only their heads outside the machine, while the device enveloped their bodies, according to the U.S. Centers for Disease Control and Prevention. It operated using negative pressure ventilation (NPV), which “simulates natural breathing by creating negative pressure around the chest, enabling the lungs to expand and draw in air,” explains Dr. Jim Mendez, a clinical associate professor of nursing at Villanova University.

For numerous polio sufferers, the iron lung was vital for survival, explains Dr. Daniel Salerno, a pulmonary and critical care physician and faculty member at Temple University. Patients often shared large wards. While many relied on the iron lung for just a week or two until recovery, about one in 200 faced lasting paralysis in their respiratory muscles. These individuals depended on the iron lung for many years, possibly the rest of their lives, according to Salerno.

Is the iron lung still in use today?

Following the introduction of the first licensed polio vaccine in the U.S. in 1955, polio cases declined sharply, leading to a significant drop in the use of the iron lung, Mendez observes.

Paul Alexander, one of the last known individuals in America to use an iron lung, passed away in early 2024 at 78. After contracting polio as a child in 1952, he relied on the iron lung throughout his life. Despite the numerous physical challenges, Alexander pursued further education, practiced law for three decades, and authored an autobiography. He shared his extraordinary journey on TikTok, educating his followers about life in an iron lung and raising awareness about the millions of children worldwide who remain unvaccinated against polio.

Efforts to eradicate polio are ongoing globally. Since 1988, cases of wild poliovirus have decreased by over 99%, yet the disease is still endemic in two countries, Pakistan and Afghanistan. International organizations have achieved remarkable success in spreading polio vaccinations, and according to the World Health Organization, more than 20 million individuals who might have been paralyzed by polio are now able to walk.

What has replaced the iron lung?

When it was first introduced, the iron lung was seen as an advanced mechanical ventilator. Despite its shortcomings, “the device led to innovations in ventilator technology and critical care, paving the way for the creation of positive pressure ventilators and other life-support systems found in today’s ICUs,” notes Mendez.

Today’s ventilators employ positive pressure ventilation (PPV) as opposed to the NPV used by the iron lung. Although the iron lung was less invasive compared to modern devices, it proved ineffective for treating acute or severe respiratory issues requiring high-pressure support, such as pneumonia, COVID-19, and emphysema.

“Additionally, the iron lung underscored the significance of managing respiratory failure, which has become fundamental in critical care medicine,” Mendez states. “In many ways, the iron lung wards were the forerunners of modern medical ICUs,” adds Salerno. ICUs today are equipped to handle a wide array of conditions, from gastrointestinal bleeding to kidney failure, yet their roots are deeply intertwined with respiratory care, according to him.