Abstract
BACKGROUND: Long-term non-invasive ventilation (NIV) is as an established treatment option for chronic hypercapnic COPD patients. Beneficial effects have also been shown during exercise, but this is restricted to rehabilitation programs. New portable NIV (pNIV) devices may now enable NIV application during walking at home. STUDY DESIGN AND METHODS: In two randomized crossover trials, the impact of pNIV on dyspnea and endurance capacity was investigated in patients with moderate to severe COPD. Participants performed a standardized 6-min walking test, with and without pNIV, using a pre-set inspiratory/expiratory positive airway pressure of 18/8 cmH(2)O. The first study was performed in NIV-naïve patients (Study I), while the second study was performed in those already established on long-term NIV (Study II). RESULTS: 38 patients (66.9 ± 7.4 years, mean FEV(1): 30.3 ± 8%pred) and 23 patients (67.6 ± 8.7 years, mean FEV(1): 29.8 ± 10.4%pred) participated in Study I and II, respectively. In Study I, the mean difference in the Borg Dyspnea Scale (BDS, primary outcome) score following walking was 3.2 (IQR 2-4) without pNIV, compared to 2.6 (IQR 1-4) with pNIV (ΔBDS 0.65, P = 0.04), while walking distance increased from 311.8 m (95%CI 276.9-346.6 m) to 326.3 m (95%CI 291.5-361.2 m) (P = 0.044) when pNIV was used. Accordingly, in Study II, the mean difference in BDS was 4.4 (IQR 3-6) without pNIV, compared to 4.5 (IQR 3-6) with pNIV (ΔBDS 0.09, P = 0.54), while walking distance decreased from 291.5 m (95%CI 246.1-336.9 m) to 258.4 m (95%CI 213-303.8 m) (P ≤ 0.001). INTERPRETATION: The use of a pNIV device during walking can improve dyspnea and walking distance in patients with moderate to severe COPD. Patients who do not already receive long-term NIV therapy are more likely to benefit compared to those undergoing long-term NIV. Careful patient selection is mandatory. Clinical Trial Register: DRKS00013203; DRKS00012913 registered October 20th 2017 and October 16th 2017; https://www.drks.de/drks_web/.