English: The machine was invented by Carl-Gunnar Engström (1912-1987), a Swedish physician and engineer. Used in operating theatres or on wards, this artificial respirator delivers air straight into the lungs using an endotracheal tube placed into the windpipe. The model became widely used following the polio epidemic of Copenhagen in 1952 and was also used to temporarily paralyse and artificial ventilate patients with breathing difficulties. The respirator was made by the Swedish company Mivab.