• Airways inflammation and bronchospasm increasing airways resistance (RL)

• Sputum retention increases airways resistance (RL)

• Expiratory flow limitation results in intrinsic positive end expiratory pressure (TL)

• Emphysematous lung with loss of lung elasticity (EL)

• Upper airway obstruction (RL)

• Reduced chest wall compliance (EL)

• Early airway closure causing intrinsic positive end expiratory pressure (TL)

• Upper airway obstruction (RL)

• Sputum retention increasing airways resistance (RL)

• Reduced chest wall compliance (EL)

• Lung hyperinflation impairing diaphragm contractility with preserved diaphragm strength

• Impaired diaphragm contractility caused by inflammation-related proteolysis

• Impaired gas exchange, increasing ventilatory demand

• Reduced respiratory muscle strength and expiratory reserve volume

• Respiratory muscle weakness

• Impaired chest wall excursion

• Increased NRD inadequate for the load–capacity imbalance

• Increase NRD inadequate for the load–capacity imbalance

• Blunted hypercapnic ventilatory response

• Reduced and inadequate for the load–capacity imbalance