iron lung, mechanical medical device, sufficiently large to enclose most of an individual’s body, used to maintain respiration in persons who are unable to breathe on their own. An iron lung, the main portion of which consists of a horizontal metal cylinder, essentially acts as a mechanical respirator, wherein a bellows positioned at the foot end of the machine moves in and out to produce changes in pressure that stimulate breathing. Historically, the iron lung was used for patients affected by paralysis caused by polio; many such patients were unable to breathe on their own. After the early 1950s, following ...(100 of 525 words) Access the full article Help support true facts by becoming a member. Subscribe today!