Agonist Delivery by High-Flow Nasal Cannula During COPD Exacerbation

BACKGROUND: Whereas high-flow nasal cannula (HFNC) oxygen therapy is increasingly used in patients with exacerbation of COPD, the effectiveness of [[beta].sub.2] agonist nebulization through HFNC has been poorly assessed. We hypothesized that salbutamol vibrating-mesh nebulization through HFNC improves pulmonary function tests in subjects with COPD. METHODS: We conducted a physiological crossover study including subjects admitted to the ICU for severe exacerbation of COPD. After subject improvement allowing a 3-h washout period without bronchodilator, pulmonary function tests were performed while breathing through HFNC alone and after salbutamol vibrating-mesh nebulization through HFNC. The primary end point consisted in the changes in FE[V.sub.1] before and after salbutamol nebulization. Secondary end points included the changes in FVC, peak expiratory flow (PEF), airway resistance, and clinical parameters. RESULTS: Among the 15 subjects included, mean (SD) FE[V.sub.1] significantly increased after salbutamol nebulization from 931 mL (383) to 1,019 (432), mean difference +87 mL (95% CI 30-145) (P 5 .006). Similarly, FVC and PEF significantly increased, +174 mL (95% CI 66-282) (P 5 .004) and +0.3 L/min (95% CI 0-0.6) (P 5 .037), respectively. Airway resistances and breathing frequency did not significantly differ, whereas heart rate significantly increased after nebulization. CONCLUSIONS: In subjects with severe exacerbation of COPD, salbutamol vibrating-mesh nebulization through HFNC induced a significant bronchodilator effect with volume and flow improvement. Key words: COPD; high-flow nasal cannula oxygen; nebulization; aerosol; respiratory function tests.