Feasibility of non-invasive respiratory drive and breathing pattern evaluation using CPAP in COVID-19 patients

PURPOSE: Increased respiratory drive and respiratory effort are major features of acute hypoxemic respiratory failure (AHRF) and might help to predict the need for intubation. We aimed to explore the feasibility of a non-invasive respiratory drive evaluation and describe how these parameters may help to predict the need for intubation. MATERIALS AND METHODS: We conducted a prospective observational study. All consecutive patients with COVID-19-related AHRF requiring high-flow nasal cannula (HFNC) were screened for inclusion. Physiologic data (including: occlusion pressure (P0.1), tidal volume (Vt), inspiratory time (Ti), peak and mean inspiratory flow (Vt/Ti)) were collected during a short continuous positive airway pressure (CPAP) session. Measurements were repeated once, 12–24 h later. RESULTS: Measurements were completed in 31 patients after the screening of 45 patients (70%). P0.1 was high (4.4 [2.7–5.1]), but it was not significantly higher in patients who were intubated. The Vt (p = .006), Vt/Ti (p = .019), minute ventilation (p = .006), and Ti/Ttot (p = .003) were higher among intubated patients compared to non-intubated patients. Intubated patients had a significant increase in their diaphragm thickening fraction, Vt, and Vt/Ti over time. CONCLUSIONS: Non-invasive assessment of respiratory drive was feasible in patients with AHRF and showed an increased P0.1, although it was not predictive of intubation.