Fig. 1From: Non-invasive ventilation in the treatment of early hypoxemic respiratory failure caused by COVID-19: considering nasal CPAP as the first choiceProportion of patients with COVID-19 receiving NIV or HFNO in ICU among different studies. Data are n (%). COVID-19, coronavirus disease 2019; NIV, non-invasive ventilation; HFNO, high flow nasal oxygen; ICU, intensive care unit, N.A., not applicableBack to article page