Figure 4.

Lung function and ultrasound before and after inhalation of Salbutamol. a) FEV₁ increased significantly in healthy and COPD subjects (healthy: p = 0.01, GOLD 1: p = 0.011, GOLD 2: p = 0.015, GOLD 3: p = 0.012). b) Airway resistance decreased significantly in healthy subjects (p = 0.0002) as well as in GOLD stage 1 (p = 0.005) and GOLD stage 3 (p = 0.032). c) Residual volume decreased significantly in healthy subjects (p = 0.033) as well as in GOLD stage 1 (p = 0.016) and GOLD stage 3 (p = 0.02). d) There was no significant difference of frequency shift during non-forced maximum breathing in any group.