A simple, low-cost Bag Valve Mask (BVM) ventilator to help critically-ill COVID-19 patients has been rapidly designed by experts at Cranfield University (UK) and built in Georgia Tech (USA) in a matter of days.
https://www.cranfield.ac.uk/press/news-2020/cranfield-university-helps-create-new-low-cost-simple-ventilators-for-covid19-patients
