iron lungs c.WHO/21618/March of Dimes
WHO/21618/March of Dimes, Birth Defects Foundation

Five to 10 per cent of polio victims can suffer paralysis of their breathing muscles, threatening death by asphyxiation. To guard against this, a breathing apparatus called the iron lung was developed in the 1930s. Iron lungs became a common sight in North American hospital wards, like this one in Los Angeles, through the 1950s.