Di mussi et al. explores the potential usefulness of high-flow nasal cannula (HFNC) oxygen therapy in the post-extubation phase of patients suffering from chronic obstructive pulmonary diseases.
HFNC generates a positive end expiratory pressure, with a more predictable inspired oxygen fraction. The warmed and humidified air also improves muco-cilliary function (spoletini et al chest 2015). Furthermore, HFNC produces a significant CO2 wash out effet of the nasopharyngeal space. To determine the potential positive impact of HNFC in the course of extubations, Di mussi et al. propose alternative therapy with or without HNFC (time period of 1hour) and analyze the impact on work of breathing. To calculate the work of breathing they used the neuroventilatory drive with electrical diaphragmatic activity and the inspiratory trans-diaphragmatic pressure-time product per minute (PTP DI/min).
They identify a significant decreased with HFNC in neuroventilatory drive and work of breathing compared with conventional O2 therapy. Of note, only 57% of COPD patients were admitted for acute exacerbation of COPD.
The main limitation of this study is the unblinded, monocentric design. Moreover the limited number (n=14) of patients, with various etiologies of respiratory failures reduces the impact of the results. Nevertheless, this pilot study highlights the potential beneficial impact of systematic use of HFNC
Keys points
- HFNC significantly decreases the neuroventilatory drive and work of breathing in patients with COPD who had received mechanical ventilation.
- HFNC should be considered systematically after extubation in COPD patients as an alternative therapy to NIV.
- Large prospective multicentric studies are needed to elucidate the real impact of such therapies in acute exacerbation of COPD