Countries with more fragile medical systems, for example in Low and Middle-Income countries (LMIC), need low-cost ventilators to raise the capacity of their healthcare systems. LMICs are likely to be left out of the current surge in ventilator development for COVID-19 due to international shortages and prohibitive costs. COVID-19 has highlighted the need for low-cost ventilators internationally beyond the pandemic. We focus especially on field use, e.g. ambulances, patient transport and emergency and critical care.