Table 1

Factors affecting respiratory mechanics

Increased airway resistance

Reduced compliance

Tube (small diameter, sputum retention)

Chest wall

Central airways

Edema

Tracheostomy malposition

Elevated abdominal pressure

Sputum plug

Pleural fluid and ascites

Corpus alienum (after trauma)

Obesity

Tracheomalacia or tracheal stenosis

Lung

Small airways

Intrinsic positive end-expiratory pressure

Asthma and chronic obstructive pulmonary disease

Alveolar filling (edema, pus, and collapse)

Acute respiratory distress syndrome

Pneumonia

Interstitial lung disease and fibrosis

Heunks and van der Hoeven Critical Care 2010 14:245   doi:10.1186/cc9296