Italian hospital used 3DPrinting technology to print valves needed for respiratory system in less that 24 hours directly at hospital 

https://www.3dprintingmedia.network/covid-19-3d-printed-valve-for-reanimation-device/

For more detailed specification : 

https://grabcad.com/library/positive-ending-expiratory-pressure-valve-1/details?folder_id=8029424

WHO : Davide Sher

Newspaper : from Lonati

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