Variables | Normocapnic COPD | Hypercapnic COPD | Controls |
| Slope | y-intercept | r | Slope | y-intercept | r | Slope | y-intercept | r |
CBV-Pa,CO2 mL·100 g−1·kPa−1 | 1.59±0.91 | −5.18±5.27 | 0.9 | 1.23±0.67* | −5.16±3.56 | 0.77 | 2.10±1.35 | −7.02±7.1 | 0.66 |
V′I-Pa,CO2 L·min−1·kPa−1 | 8.2±4.9* | −33.4±26.2* | 0.96 | 5.5±4.4*** | −26.7±34.3** | 0.93 | 13.9±7.1 | −62.9±36.8 | 0.85 |
P0.1 Pa,CO2 cm H2O·kPa−1 | 2.65±1.84 | −8.67±9.3 | 0.81 | 2.83±1.50 | −12.38±9.18 | 0.80 | | | |