what is iron lung

An iron lung is a large mechanical respirator that helps a person breathe when their own chest and diaphragm muscles are too weak or paralyzed to do the job, most famously during polio outbreaks in the 20th century.

What is an iron lung?

• It is a negative-pressure ventilator : a metal cylinder that surrounds the body from the neck down and changes air pressure around the chest to make the lungs draw air in and push it out.

• Only the patient’s head sticks out; the neck is sealed with a padded collar so the chamber stays airtight.

• It was mainly used for people with polio whose breathing muscles were paralyzed, but also for some cases of poisoning or other illnesses that caused respiratory failure.

How it works (simple picture)

• The patient lies flat inside the cylinder, head outside, body inside the sealed chamber.

• A motor-driven bellows or diaphragm at one end of the machine rhythmically changes the pressure inside the tank.
  • When the machine lowers the pressure inside (a slight vacuum), the patient’s chest is gently pulled outward, so air flows into their lungs (inhalation).

* When the pressure rises back toward normal, the chest falls back, pushing air out of the lungs (exhalation).

• This copies how our own diaphragm normally works, but from the outside of the body instead of using the person’s muscles.

Quick image in your mind:
Think of the body as a balloon in a box. If you lower the pressure in the box, the balloon expands; if you raise it, the balloon shrinks. The iron lung does that to the chest.

Why it mattered historically

• During major polio epidemics in the 1930s–1950s, hospital wards sometimes had rows of iron lungs keeping many patients alive at once.

• Some designs were even large “room-sized” negative-pressure units that could support several patients together.

• This technology is one of the ancestors of today’s intensive care units and modern ventilators, which mostly use positive-pressure (pushing air into the lungs with a tube) instead of surrounding the whole body.

Do people still use them?

• After effective polio vaccines and modern ventilators came along, iron lungs became very rare.

• A tiny number of people, mostly long-term polio survivors, have continued to live with and maintain old iron lungs at home into recent decades, because they are used to them and they still work for their specific condition.

TL;DR: An iron lung is a big, body-enclosing breathing machine that uses changing air pressure around the chest to pull air in and out of the lungs, historically lifesaving for polio patients who couldn’t breathe on their own.

Information gathered from public forums or data available on the internet and portrayed here.