Management of Dynamic Pulmonary Compliance in COPD and Asthma

Pathophysiology of Altered Dynamic Compliance

The European Respiratory Society suggests that dynamic pulmonary compliance is altered by two main mechanisms in COPD: static factors, such as loss of elastic lung recoil, and dynamic factors, such as limitation of expiratory flow during quiet breathing, leading to dynamic hyperinflation 1, 2
Dynamic hyperinflation generates intrinsic positive end-expiratory pressure (PEEPi), an inspiratory threshold load that must be overcome by the inspiratory muscles to initiate inspiration, dramatically increasing the work of breathing 1, 4

The American Thoracic Society recommends that spirometry with a post-bronchodilator FEV1/FVC ratio <0.7 remains the diagnostic standard for airway obstruction and cannot be replaced by resistance measurements 10

The European Respiratory Society recommends initiating combined bronchodilator therapy with long-acting beta-agonists and anticholinergics to reduce airway obstruction and improve lung emptying in patients with COPD 5
The American Thoracic Society suggests that all patients with COPD who present with dyspnea, exercise intolerance, or activity restriction should be referred to pulmonary rehabilitation, regardless of the degree of obstruction 6, 5
The American Journal of Respiratory and Critical Care Medicine recommends non-invasive ventilation with positive pressure (NIPPV) as an adjunct during pulmonary rehabilitation or nocturnally to unload the respiratory muscles in patients with severe COPD (FEV1 <50% predicted) 8

The European Respiratory Society recommends prescribing long-term oxygen therapy (LTOT) to maintain SpO2 ≥90% at rest, sleep, and exercise when PaO2 <7.3 kPa (55 mmHg) 6, 5
The European Respiratory Society suggests that LTOT improves survival, exercise, sleep, and cognitive function in hypoxemic patients 6, 5

The American Journal of Respiratory and Critical Care Medicine recommends that during mechanical ventilation in acute exacerbations, the volume minute should be reduced and the expiratory time increased to limit dynamic hyperinflation, accepting controlled hypercapnia if necessary 8

The European Respiratory Society recommends not relying on peak flow measurements (PEF) for diagnosis or severity classification, as PEF cannot differentiate between obstructive and restrictive patterns or provide detailed information necessary for appropriate disease classification 11
The European Respiratory Society suggests not withdrawing oxygen prematurely, as suspending oxygen due to improvement in PaO2 in patients whose need was determined in a stable state can be harmful 6, 5