this didn't get added, but you can use CPAP , sleep apnea machines as ventilators
https://emcrit.org/pulmcrit/cpap-covid/The above model would suggest that COVID patients really need positive
pressure more than anything else. For example, their work of
breathing is often tolerable – so they may not need much mechanical
support for the work of breathing (indeed, mechanical support could
lead to injuriously large tidal volumes).
The best modality to provide lots of positive pressure is simply
Continuous Positive Airway Pressure (CPAP). CPAP may not seem
dramatic, but this modality actually provides the greatest amount of
positive pressure to allow for the most powerful recruitment