How the Iron Lung Artificial Respirator Works

A 1933 patent for a mechanical respirator that uses external air pressure changes to force a patient's lungs to expand and contract.

What it covers

The device, commonly known as an iron lung, creates a sealed environment around a patient's body, leaving only the head exposed. By using a pump to rhythmically lower and raise the air pressure inside the chamber, the device forces the patient's chest to expand and deflate. This mechanical action mimics the natural process of breathing for individuals who have lost the ability to control their own diaphragm muscles.

What it doesn't cover

• —Does not cover positive-pressure ventilators that push air directly into the lungs through a tube.
• —Does not cover portable or wearable breathing assistance devices.
• —Does not cover electronic sensors or automated feedback loops for monitoring blood oxygen levels.

The clever bit

The invention cleverly uses external negative pressure to manipulate the chest wall, avoiding the need for invasive procedures or direct intubation of the patient's airway.

Why it matters

This invention was critical during the mid-20th century polio epidemics, providing life-saving support for patients suffering from respiratory paralysis. It represents a foundational moment in intensive care medicine, proving that mechanical intervention could sustain life during prolonged respiratory failure.

Real-world examples

• 1.The Drinker Respirator
• 2.Historical polio ward iron lung machines