High-flow Oxygen Therapy vs Non-invasive Ventilation: Comparison of Alveolar Recruitment in Acute Respiratory Failure

High-flow Oxygen Therapy Versus Non-invasive Ventilation: a Randomised Physiological Cross-over Study of Alveolar Recruitment in Acute Respiratory Failure

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.

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).

Inclusion Criteria:

• Adult patients referred in ICU
• with hypoxemic acute respiratory failure due to a community acquired pneumonia confirmed by chest X ray,
• with PaO2 < 60mmHg in ambient air, without hypercapnia (PaCO2 < 45 mmHg),
• requiring more than 6L/min of O2 on admission with high concentration FM, and justifying HFNC or NIV for the attending ICU physician

Exclusion Criteria:

• cardiogenic pulmonary oedema,
• moderate to severe underlying respiratory disease including COPD (chronic obstructive pulmonary disease)
• contraindication to or failure of previous NIV or HFNC with the need for immediate invasive ventilation
• pregnant or breast-feeding women
• carrier of an implantable defibrillator or pacemaker
• body mass index (BMI)>50 kg/m2
• with cutaneous lesion next to the positioning zone of the Pulmovista® (Dräger, Lübeck, Germany) belt