The resuscitators, also called Ambu bags, are generally on-hand in large quantities. They are designed to be operated by hand, by trained technicians, to inflate patient lungs until a better device such as a ventilator becomes available. In operation, the technician inserts a tube into the patient’s airway and then pumps air into the lungs by squeezing and releasing the flexible pouch.
The usual approach to turning bag resuscitators into make-shift ventilators is to add a mechanical means of squeezing the bag. Teams at facilities that include M.I.T., UC San Diego, and the University of Minnesota all have efforts focused around this basic idea.
However, all these projects are taking place with the input of physicians skilled in resuscitation, unlike a number of open-source activities with similar goals. The reason is simple: It is quite easy to put a patient on an artificial ventilation device and make things worse rather than better.