High-flow oxygen therapy vs non invasive ventilation: a prospective randomized cross-over physiological study of alveolar recruitment in acute respiratory failure

Abstract

High-flow nasal cannula (HFNC) oxygen therapy has recently shown clinical benefits in hypoxemic acute respiratory failure (ARF) patients, while non-invasive ventilation (NIV) remains debated in this indication. We evaluated the effect of HFNC on alveolar recruitment and lung volumes in hypoxemic ARF compared to NIV and facial mask (FM). A prospective randomized cross-over physiological study was conducted. Eligible patients had to present hypoxemic ARF due to pneumonia. The primary endpoint was the comparison of global and regional end-expiratory electrical lung impedance (EELI) between NIV and HFNC. Secondary endpoint was the comparison, between the 3 techniques, of lung volumes (global and regional TV), respiratory parameters, hemodynamic tolerance, dyspnea and comfort. NIV and HFNC significantly increased the global EELI compared to FM (2056 [1070; 2825] vs. 4083 [2928; 5134], p=0.001 and 1448 [1028; 3542] vs 2921 [1706; 4850], p=0.0001, respectively). No global EELI difference was found between NIV and HFNC (4083 [2928; 5134] vs 2921 [1706; 4850], p=0.4). Global and regional TV increased under NIV compared to HFNC (p This study demonstrates a similar benefit of HFNC and NIV on alveolar recruitment. By contrast to HFNC, NIV also increases lung volumes which may contribute to its potentially deleterious effect during hypoxemic ARF.