Iron Lung

Illustrative case: Imagine a 5-year-old girl who, one summer morning, wakes up with fever and muscle pain. Within a few days, her legs stop responding and, shortly after, her breathing begins to fail. Doctors place her inside a large metal cylinder, which now breathes for her. The scene is fictional, but it summarizes what happened to thousands of real children during the poliomyelitis epidemics of the 20th century.

What is the iron lung

The iron lung is a negative pressure ventilator. It was created in 1927 by Philip Drinker and Louis Agassiz Shaw at Harvard University, and refined a few years later by John Haven Emerson.

How it works is different from what most people imagine when they think of a "breathing apparatus." The patient lies inside a hermetic metal cylinder with only their head outside, held in place by a rubber ring that seals the neck. A system of pumps varies the pressure inside the cylinder. When the pressure drops, the chest expands and air enters the lungs. When the pressure rises, the chest retracts and air exits. In other words, the machine does not push air into the patient. It recreates, from outside to inside, the natural movement of breathing.

Why this was the choice: which diseases necessitated this need

The iron lung did not treat the disease itself. It sustained breathing while the muscles responsible for this movement were paralyzed. The condition most associated with the apparatus is poliomyelitis, a viral infection that can attack the motor neurons of the spinal cord and compromise the diaphragm and chest muscles.

But poliomyelitis was not the only indication. Any condition capable of weakening respiratory muscles without directly damaging the lungs could lead to this need, including:

  • Guillain-Barré syndrome, an autoimmune disease that can cause progressive muscle weakness and affect about one quarter of patients to the point of requiring ventilatory support
  • Myasthenia gravis, which compromises transmission between nerve and muscle
  • Botulism, an intoxication that blocks nerve signals to muscles
  • Spinal cord injuries, especially the highest ones, near the neck
  • Tetanus, which can generate spasms and compromise breathing

In all these cases, the lungs themselves function normally. The problem lies in the "pump" that moves the air, that is, in the muscles and the nerves that control them.

What the routine was like for those dependent on the apparatus

During the polio epidemics of the 1930s to 1950s, hospitals had entire rooms of iron lungs, and many patients spent weeks or months inside them until they recovered enough strength to breathe on their own. Some, however, never recovered that strength and became permanently dependent on the machine, sleeping inside it every night for the rest of their lives.

Why the iron lung fell into disuse

Two advances changed this scenario. The first was the poliomyelitis vaccine, made available starting in 1955, which drastically reduced the number of new cases and, with that, the main cause that led to the use of the apparatus. The second was the development of modern mechanical ventilators, which function on the opposite principle: instead of varying the pressure around the body, they push air directly into the lungs through a tube in the trachea. These devices are smaller, more precise, and allow for care of patients with different degrees of severity, which made them the standard in intensive care medicine from the second half of the 20th century onward.

The end of an era

In 2026, the iron lung ceased to have any known users. Paul Alexander, who had depended on the apparatus since the 1950s because of polio, died in March 2024. Martha Lillard, who contracted the disease at age 5 in 1953 and spent more than seven decades using the machine, died on June 26, 2026, at age 78, as a result of complications from post-polio syndrome and long COVID. With her death, the chapter of continuous use of the iron lung in the United States practically closed, and there is no record of equivalent use in other countries currently.

Is negative pressure ventilation still used today?

In quite a limited way. There are simplified and portable versions of the same principle, such as cuirass-type ventilators (a kind of rigid "shell" that covers only the chest) and jacket ventilators. They appear occasionally in medical literature for the home treatment of chronic respiratory insufficiency, especially in neuromuscular diseases, but their use today is considered experimental and restricted to very specific situations, without the same volume of scientific evidence accumulated by the methods that replaced them.

What science recommends today

For people with respiratory insufficiency of neuromuscular cause, similar to what previously required the iron lung, current guidelines prioritize non-invasive positive pressure ventilation, done by facial or nasal mask connected to an external device, without the need for a tube or surgery. This approach is supported by various studies, is more comfortable, allows the patient to speak, eat, and sleep more naturally, and for this reason is usually the first choice whenever clinical condition permits. When non-invasive ventilation is insufficient or the patient does not tolerate it, the alternative is invasive ventilation through tracheostomy, indicated more carefully as it involves greater risk of infection and secretion accumulation.

Thus, although the iron lung was decisive in its time and occupies a symbolic place in the history of respiratory medicine, today's clinical practice is supported by safer technologies and much more robust evidence than what was available a century ago.

This content is informational in nature and does not replace consultation, diagnosis, or treatment by a healthcare professional. In case of questions about respiratory symptoms or neuromuscular diseases, seek medical guidance.

Dr. Rebeca Soares Andrade CRM - GO 39335