No shortage of non-invasive ventilators during second wave: Expert May 24, 2021 NIV makers are still getting orders from State governments and hospitals, says ResMed official The number of non-invasive ventilators (NIV) in the country went up more than five times in the last one year, and this could be the reason why there were no high-pitched calls for NIVs unlike oxygen concentrators during the second wave. “At the beginning of the pandemic last year, all were talking about ventilators, particularly NIVs. Nobody was talking about oxygen at that point in time because there was ample oxygen supply. This time most of news was around oxygen and oxygen concentrators. We did not hear much about NIV because they were in ample supply,” said Sibasish Dey, head of Medical Affairs for Asia and Latin America at ResMed, a world leader in respiratory devices.