Nasal high-flow oxygen in patients with hypoxic respiratory failure: effect on functional and subjective respiratory parameters compared to conventional oxygen therapy and noninvasive ventilation

Abstract

Introduction This study compared a nasal high-flow oxygen therapy (NHFO2) with conventional oxygen therapy via a Venturi mask (VM) or noninvasive ventilation (NIV) in patients with hypoxic respiratory failure. Study endpoints were functional respiratory parameters, dyspnea, patient comfort and a global rating by the patients. Methods We included 14 patients with hypoxic respiratory failure (paO2 <55 mmHg under room air). Exclusion criteria were ventilatory failure, hemodynamic instability, cardiogenic pulmonary edema, NIV contraindications and inability to cooperate. Patients were treated in a randomized order for 30 minutes each with NHFO2 (Optiflow; Fisher-Paykel), VM or NIV, using a FiO2 of 0.6. Every treatment phase was preceded by a 15-minute baseline phase in which the patients received oxygen via a standard nasal prong (SaO2 goal >88%). At the end of each treatment phase vital signs and blood gases were measured and patients rated their dyspnea and their general comfort on a 10-point scale. Finally, patients were ask for a global rating of all three devices ranging from 1 (very good) to 6 (failed) and could choose one device for further treatment. Results The paO2 was highest under NIV with 129 +/- 38 mmHg, followed by NHFO2 (101 +/- 34 mmHg, P <0.01 vs. NIV) and VM (85 +/- 21 mmHg, P <0.001 vs. NIV, P <0.01 vs. NHFO2, ANOVA). All other vital and blood gas parameters did not show significant differences. Dyspnea rating on a 10-point Borg scale was significantly better under NHFO2 (2.9 +/- 2.1) and VM (3.3 +/- 2.3) compared to NIV (5.0 +/- 3.3) (P <0.05, vs. NHFO2 or VM). Comfort rating showed similar results: NHFO2 2.7 +/- 1.8; VM 3.1 +/- 2.8; NIV 5.4 +/- 3.1 (P <0.05, NIV vs. NHFO2 or VM). In the final global rating using German school grades from 1 to 6 NHFO2 also received the best rating (2.3 +/- 1.4), followed by VM (3.2 +/- 1.7, P = NS vs. NHFO2) and NIV (4.5 +/- 1.7, P <0.01 vs. NHFO2 and P <0.05 vs. VM). For further treatment 10 patients chose NHFO2, three VM and one NIV. Conclusion NHFO2 is a promising new device for oxygen supply in respiratory failure, offering better oxygenation than the VM and better patient comfort and tolerance than NIV.