Pulmonary vascular resistance vs lung volume relationship
Core concept
- Two populations of pulmonary vessels, pulled in opposite directions by lung volume
- Alveolar vessels (capillaries in the alveolar septa) - compressed as the lung inflates
- Extra-alveolar vessels (arteries/veins in interstitium) - held open by radial traction; collapse as the lung deflates
- -> U-shaped curve. PVR is minimal at FRC
- High volume (TLC, high PEEP) - alveolar vessels stretched and squashed -> inc PVR
- Low volume (RV, atelectasis) - loss of radial traction + hypoxic pulmonary vasoconstriction -> inc PVR
- The lung is the only vascular bed where inflating the organ can increase its own afterload
3 more sections, plus exam facts
Premium unlocks every note across every specialty, and the full exam fact library behind it.
Get premium access