Baseline characteristics
| Bi-level PAP (n=29) | CPAP (n=31) | |
|---|---|---|
| Age (years) | 53.2 (10.7) | 52.9 (10.0) |
| Gender (% male)* | 48.3% (30.1% to 66.5%) | 58.1% (40.7% to 75.4%) |
| Presentation* | 37.9% Acute (20.3% to 55.6%) | 45.2% Acute (27.6% to 62.7%) |
| Comorbidities (n) | 3.43 (1.85) | 2.94 (1.44) |
| BMI (kg/m2) | 55.3 (12.9) | 54.5 (11.0) |
| Neck circumference (cm) | 48.9 (5.85) | 49.9 (3.76) |
| Waist circumference (cm) | 147.4 (22.9) | 146.1 (16.7) |
| Hip circumference (cm) | 154.1 (25.7) | 155.5 (20.5) |
| Waist:hip ratio | 0.966 (0.119) | 0.945 (0.078) |
| Previous PAP therapy* | 44.8% (26.7% to 62.9%) | 67.7% (51.3% to 84.2%) |
| Spirometry | ||
| FEV1 (L) | 1.99 (0.83) | 1.85 (0.68) |
| FEV1 (% predicted) | 64.0 (17.8) | 60.3 (15.4) |
| FVC (L) | 2.49 (1.03) | 2.32 (0.90) |
| FVC (% predicted) | 62.0 (18.2) | 57.4 (16.8) |
| FER (per cent) | 81.2 (8.98) | 80.6 (5.79) |
| ABG (inclusion criteria assessment) | ||
| pH | 7.37 (0.05) | 7.37 (0.04) |
| PaCO2 (mm Hg) | 60.1 (17.2) | 59.1 (9.9) |
| PaO2 (mm Hg) | 60.2 (11.7) | 61.1 (13.2) |
| Bicarbonate (mmol) | 31.8 (7.61) | 33.5 (4.10) |
| Base excess | 7.49 (8.41) | 7.73 (5.96) |
| Supplemental oxygen* | 13.8% (3.9% to 31.7%) | 16.1% (5.4% to 33.7%) |
Values represent mean (SD), or * percentage (95% CIs).
ABG, arterial blood gas; BMI, body mass index; FER, forced expiratory rate, FEV1/FVC; PAP, positive airways pressure.