Beneficial effects of nasal high flow oxygen therapy after weaning from non­invasive ventilation: A prospective observational study

It remains unknown whether application of nasal high flow (NHF) is effective after liberation from non-invasive ventilation (NIV). This study was aimed at investigating the effect of NHF in patients ready for weaning from NIV. With institutional ethic committee approval, patients receiving NIV due to hypoxemic respiratory failure for more than 24 hours were enrolled. After passing the weaning criteria with continuous positive airway pressure (CPAP) mode [fraction of inspiratory oxygen (FIO₂) ≦0.5, positive end expiratory pressure (PEEP) 4 cmH₂O], patients received NHF (Flow 50 L/min, FIO₂ ≦0.5) immediately after liberation from NIV. Before the initiation of the study, eight sequential patients who received oxygen via face mask after NIV treatment, served as the historical control. Respiratory parameters [partial pressure of arterial oxygen (PaO₂) to FIO₂ ratio (P/F ratio), respiratory rate (RR)] 1 hour after liberation from NIV were evaluated with those during NIV as the primary outcome. The frequency of rescue NIV therapy, intubation, and respiratory failure were also recorded. Nine eligible patients received NHF therapy after liberation from NIV. P/F ratio and RR did not change significantly compared with those during NIV (231 ± 43.6 versus 250.7 ± 34.2 mmHg, 20.8 ± 2.3 versus 21 ± 1.6/min), while P/F ratio decreased significantly in the historical control group (194.3 ± 20.1 versus 255.9 ± 58.1 mmHg, p=0.013). Rescue NIV therapy, intubation, and respiratory failure never occurred in the NFH group, although two patients received NIV rescue therapy, of whom one was intubated in the historical control. NHF after liberation from NIV might be effective in patients recovering from hypoxemic respiratory failure. Registration number: UMIN000014133 (UMIN-CTR).