Understanding the Iron Lung: How it Works
The iron lung is a type of negative pressure ventilator, a device that assists breathing for individuals whose respiratory muscles are unable to function on their own. This apparatus takes the form of a large, horizontal cylinder. The patient’s head remains outside the chamber, with a rubber seal around the neck creating an airtight environment.
Breathing naturally occurs through negative pressure, where the diaphragm contracts and the rib cage expands, drawing air in. The iron lung mimics this natural process by varying the air pressure inside the sealed chamber. An electric motor connected to a pumping diaphragm alternately pulls air out of the cylinder and then allows air back in.
When air is pumped out, the negative pressure causes the patient’s chest and abdomen to expand, drawing air into their lungs through their mouth and nose. Conversely, when air is allowed back into the chamber, the pressure increases, allowing the patient’s chest to contract and air to be exhaled. This cyclical change in pressure provides artificial respiration.
From Polio to Modern Medicine: The Iron Lung’s Journey
The iron lung played an important role during the polio epidemics of the 20th century. Polio, a viral disease, could cause paralysis of the respiratory muscles, leaving patients unable to breathe independently. The iron lung offered a life-sustaining solution for these individuals, with hospitals often housing rows of these devices during outbreaks.
The first widely used iron lung was developed by Philip Drinker and Louis Shaw in 1928. An improved and more affordable version, the Emerson Respirator, was introduced in 1931 by John Haven Emerson, making the technology more accessible. The device became a symbol of the fight against polio, enabling many patients to survive the acute phase of the illness.
The widespread use of the iron lung began to decline with the development and adoption of the polio vaccine in the 1950s and 1960s. The vaccine reduced the incidence of paralytic polio, reducing its need. By 1959, approximately 1,200 people in the U.S. were using iron lungs, but this number steadily decreased as polio cases plummeted.
The emergence of positive pressure ventilators also contributed to the iron lung’s obsolescence. These newer machines deliver air directly into the lungs, offering greater flexibility and easier patient care compared to the bulky iron lung. While the iron lung provided negative pressure ventilation, its design made patient access and care challenging, accelerating its replacement.
Is the Iron Lung Still Used Today?
In contemporary medicine, the iron lung is obsolete due to the availability of more efficient modern ventilators. These include positive pressure ventilation that offer greater mobility and ease of use.
A few individuals worldwide still rely on an iron lung. These are typically long-term survivors of paralytic polio who have used it for decades. For these individuals, transitioning to modern alternatives can be complex and carries risks, making continued use their preferred or only viable option.
Continued use of these machines presents challenges, including difficulty finding parts for maintenance and repair, as manufacturing ceased in 1970. Maintaining these aging devices requires specialized knowledge and custom solutions. The individuals who still use them represent a link to a past era of medical technology.