The iron lung was invented in 1929 in the USA. The machine was of immense benefit in the treatment of patients with the poliomyelitis virus, which at this time was extremely prevalent. This virus (known as polio) could attack the brain and spinal cord, causing paralysis of the respiratory muscles. This prevented the lungs from expanding and contracting properly, reducing the supply of oxygen into the bloodstream.
The main component of the iron lung was an airtight box, into which the patient would be laid. This would enclose almost all of the patient's body except the head, which would emerge through a soft airtight collar. The box would then be connected to a pump which would increase and decrease the air pressure inside the box, helping the patient to breathe.
Nowadays mass immunisation has rendered the polio virus almost extinct, but the iron lung is sometimes used to help patients with nervous disorders which impede their breathing.
