Bronchodilator response of advanced lung function parameters depending on COPD severity

Figure 1. Flowchart of the study design.

Figure 2. FVC%p at (A) baseline and (B) after inhalation of SABA and additional SAMA in COPD patients and controls. Notes: The solid line to left and the hatched line to right of the BP are the segmented linear fits that join at the BP, estimated in the top of the figure (circles with the associated 95% confidence intervals). An ordinary LR line (hatched gray) and the reference and a nonparametric fit by the loess (local regression) method (gray line) are also displayed. Dots show the values of each subject. (C) The first two (A and B) linear/segmented linear curves plotted into one graph to illustrate bronchodilator response. Abbreviations: FVC, forced vital capacity; %p, percent predicted; SABA, short-acting β2 agonist; SAMA, short-acting muscarinic antagonist; BP, break point; LR, linear regression.

Figure 3. Lungfunction, before and after bronchodilators. Notes: (A) FEV1/FVC, (B) IC%p, (C) Rex and (D) FEV1%p at baseline and after inhalation of SABA and additional SAMA in COPD patients and controls. Graphs show linear regression lines or segmented regression lines (if segmentation was significant). Abbreviations: FEV1, forced expiratory volume in 1 second; FVC, forced vital capacity; IC, inspiratory capacity; %p, percent predicted; SABA, short-acting β2 agonist; SAMA, short-acting muscarinic antagonist.

Figure 4. Bronchodilator response. Notes: (A) ΔFVC%, (B) ΔFEV1/FVC, (C) ΔIC%p and (D) ΔRex in COPD patients and controls. The solid line to the left and the hatched line to the right of the BP are the segmented linear fits that join at the BP, estimated in the top of the figure (circles with the associated 95% confidence intervals). An ordinary LR line (hatched gray) and the reference and a nonparametric fit by the loess (local regression) method (gray line) are also displayed. Dots show the values of each subject. Abbreviations: FVC, forced vital capacity; FEV1, forced expiratory volume in 1 second; IC, inspiratory capacity; %p, percent predicted; BP, break point; LR, linear regression, SABA, short-acting β2 agonist (salbutamol); SAMA, short-acting muscarinic antagonist (ipratropium).

Figure 5. Relationship between ΔFEV1%p and ΔRV%p. Notes: To visualize the flow versus volume response in each patient. Dotted lines are median of ΔFEV1%p and ΔRV%p. Abbreviations: FEV1, forced expiratory volume in 1 second; %p, percent predicted; RV, residual volume.