Iron lung

An iron lung is a type of negative pressure ventilator, a mechanical respirator which encloses most of a person's body and varies the air pressure in the enclosed space to stimulate breathing. It assists breathing when muscle control is lost, or the work of breathing exceeds the person's ability. Need for this treatment may result from diseases including polio and botulism and certain poisons (for example, barbiturates and tubocurarine).

The use of iron lungs is largely obsolete in modern medicine as more modern breathing therapies have been developed and due to the elimination of polio in most of the world. In 2020, however, the COVID-19 pandemic revived some interest in them as a cheap, readily-producible substitute for positive-pressure ventilators, which were feared to be outnumbered by patients potentially needing temporary artificially assisted respiration.

The iron lung is a large horizontal cylinder designed to stimulate breathing in patients who have lost control of their respiratory muscles. The patient's head is exposed outside the cylinder, while the body is sealed inside. Air pressure inside the cylinder is cycled to facilitate inhalation and exhalation. Devices like the Drinker, Emerson, and Both respirators are examples of iron lungs, which can be powered manually or mechanically. Smaller versions, like the cuirass ventilator and jacket ventilator, enclose only the patient's torso.