LAUSR

Purpose: To identify the clinical significance of episodic nocturnal hypercapnia (eNH), mainly observed during rapid-eye-movement sleep, and the effectiveness of eNH-targeted non-invasive positive pressure ventilation (NPPV) against stable advanced chronic obstructive pulmonary disease (COPD) with eNH. Patients and methods: We enrolled patients with stable, severe, or very severe COPD with PaO 2 ≥ 55 mmHg and daytime PaCO 2 2 ) from April 2013 to January 2017. In this study, eNH was defined as an episodic increase of ≥ 5 mmHg from baseline PtcCO 2 . We retrospectively examined clinical characteristics, daytime blood gas analysis, brain natriuretic peptide (BNP), estimated pulmonary artery systolic pressure (PASP), and frequency of exacerbation, between patients with COPD with and without eNH. We applied NPPV for the patients with eNH, and compared the clinical characteristics before and after NPPV. Results: Of the twenty-seven patients, fourteen patients (51.9%) were considered to have eNH. These patients had higher BNP (p=0.047), higher estimated PASP (p=0.023), and higher frequency of exacerbations during the last year (p=0.019) compared to those without eNH. Daytime PaCO 2 decreased between before and 12 months after NPPV (p=0.038). The frequency of exacerbations one year before NPPV improved one year after NPPV (p=0.001) Conclusion: In patients with stable advanced COPD, eNH may be a risk factor of pulmonary hypertension and exacerbations. NPPV could decrease the frequency of COPD exacerbations.