Negative-Pressure Ventilation Better Oxygenation and Less Lung Injury

Interesting; back to the "iron lung" used to treat Polio patients in the 40's and 50's. Wikipedia [0] says they date back to the 1830's. The "Both Respirator" was invented in 1937, was made from plywood, and cost £100 to make. And kind of an odd echo of current events:

Visiting London in 1938 during another polio epidemic, Both produced additional respirators there which attracted the attention of William Morris (Lord Nuffield), a British motor manufacturer and philanthropist. Nuffield, intrigued by the design, financed the production of approximately 1700 machines at his car factory in Cowley, and donated them to hospitals throughout all parts of Britain and the British Empire. Soon, the Both-Nuffield respirators were able to be produced by the thousand at about one-thirteenth the cost of the American design. By the early 1950s, there were over 700 Both-Nuffield iron lungs in the United Kingdom, but only 50 Drinker devices.

[0] https://en.wikipedia.org/wiki/Iron_lung