the.com/iron lung

means A large mechanical respirator that encased a polio patient's body and used changing air pressure to pull air into and out of paralyzed lungs.

from From 'iron,' for the steel cylinder it was built from, plus 'lung,' the organ it mechanically stood in for. The device was developed in the late 1920s, often credited to Philip Drinker and Louis Shaw, and became a defining image of the polio epidemics of the mid-20th century — the plain, descriptive name sticking precisely because the machine's job was so literal: it was, in effect, a lung made of iron.