The electronics and software would be a critical component as well. It really wouldn't cost that much to develop the software/hardware or even the electronics a

The electronics and software would be a critical component as well. It really wouldn't cost that much to develop the software/hardware or even the electronics as microchips are now often cheaper than an equivalent set of discrete analog components. The _real_ costs in any medical equipment is passing FDA (or equivalent European) certifications. The most plausible way to handle these situations would be to have "pre-authorized" set of plans, bill of materials (or qualified components), and manufacturing process. Critically there would need to some sort of checklist and verification process to verify the equipment (preferably able to be performed by a third-party with minimal training). A consortium of FDA, WHO, etc worked with a established non-profit organization could design a set of plans and procedures for "emergency medical equipment". Then the entire world could be prepared for such emergencies, and possibly double as lower cost equipment for developing nations. Likely established manufacturers would lobby hard against such measures (why would hospitals pay $50-60k for a ventilator when these "open plan" units only cost $1k?). There would also be questions of reliability of such devices. These issues could be mitigated by authorizing use of such equipment only during state of emergencies. This would make sense as such equipment would possibly be of lower (or just uncertain) quality compared to normal devices. But the laws allowing for this would need to be passed, and again, that's the difficult part. The technology/manufacturing/3d printing is almost inconsequential _without_ appropriate legal infrastructure in place.