The static compliance (C) of the lung is the change in lung volume per unit change in the transpulmonary pressure
- Lung compliance is the change in unit lung volume per unit change in pressure.
- In normal lungs a small pressure gradient is needed to inflate the lungs.
- With some diseases the pressure required to fill the lungs is greater.
- Compliance is not constant and tends to rise with lung volume.
- The "easier" is it to expand the lungs the greater the compliance and vice-versa.
Decreased compliance (stiff lungs)
- Lung fibrosis
- Pulmonary oedema
- Emphysema - airflow obstruction and hyperinflation