Table 1.
Characteristics and clinical data of the included COPD patients.
| Sex, female/male (n) | 5/4 |
| Age (years) | 63 (58–72) |
| BMI (kg/m2) | 25 (22–29) |
| FEV1 (L) | 0.59 (0.52–0.75) |
| FEV1 (%pred) | 20 (16–26) |
| FVC (L) | 2.22 (1.43–2.63) |
| FVC (%pred) | 53 (44–66) |
| FEV1/FVC (%) | 28 (23–33) |
| TLC (L) | 8.01 (6.82–9.22) |
| TLC (%pred) | 134 (116–156) |
| RV (L) | 5.29 (4.88–6.21) |
| RV (%pred) | 252 (215–267) |
| RV/TLC (%) | 66 (61–74) |
| PaCO2 before NIV initiation (kPa) | 6.6 (6.2–8.9) |
| PaO2 before NIV initiation (kPa) | 8.3 (5.9–9.4) |
BMI, body mass index; FEV1, postbronchodilator forced expiratory volume in 1 s in liters (L); FVC, forced vital capacity in liters (L); RV, residual volume; TLC, total lung capacity; %pred: percentage of the predicted values [14,15]; PaO2, arterial oxygen pressure at daytime without ventilation; PaCO2, arterial carbon dioxide pressure at daytime without ventilation; kPa, kilopascal; NIV, non-invasive ventilation. Characteristics are represented by their median and inter-quartile range.