Briefly describe the factors that affect lung compliance.
Main points/concepts expected in answer.
- Surfactant • increases lung compliance • decreases surface tension at alveolar air -water- interface •prevents small alveoli from collapsing •accounts for most of hysteresis in intact lung
- Lung elastic recoil • lung compliance changes in disease states
- Lung volume • lung compliance greatest around FRC • lung compliance reduced at low and high lung volumes • gravitational effects on regional lung compliance
- Pulmonary blood volume • pulmonary venous congestion reduces lung compliance
- Lung size • specific compliance = lung compliance I PRC
- Dynamic lung compliance • influenced by airways resistance • lung compliance measured during normal breathing • less than static lung compliance • frequency dependence