Background: High-flow nasal cannula (HFNC) oxygen therapy has recently shown clinical benefits in hypoxemic acute respiratory failure (ARF) patients, while the interest of non-invasive ventilation (NIV) remains debated. The primary endpoint was to compare alveolar recruitment using global end-expiratory electrical lung impedance (EELI) between HFNC and NIV. Secondary endpoints compared regional EELI, lung volumes (global and regional tidal volume variation (TV)), respiratory parameters, hemodynamic tolerance, dyspnea and patient comfort between HFNC and NIV, relative to face mask (FM).
This physiological study showed an increase in regional ventilation with NIV but no difference in alveolar recruitment as compared to HFNC in patients with hypoxemic ARF. Although NIV provided better oxygenation than HFNC, the effect on lung volumes could explain the potentially deleterious effect of NIV in hypoxemic ARF, reinforcing the recently developed concept of patient self-inflicted lung injury.