Altered Lung Mechanics in Disease

From pEx
Jump to: navigation, search

Screen shot 2012-09-14 at 1.05.14 PM.pngFlow volume.gif

Fibrotic lung disease[edit]

  • Compliance is reduced, and pressure volume curve is reduced and shifted to the right
  • Flow is normal or even increased
  • Also occurs in interstitial and alveolar oedema, sarcoidosis, ARDS
  • Pulmonary tissue viscous resistance also increases in fibrotic disease - resistance of lobes etc rubbing over each other
  • FEV and FVC both reduced therefore in restrictive conditions - the ratio remains normal or is even increased


  • Steeper curve, shifted to the left
  • Dynamic compression of airways can occur with mild exercise causing severe disability
  • FEV reduced more than FVC - ratio <0.8 - due to loss of elastic tissue recoil surrounding the airways


  • Parallel curve shifted upwards - meaning compliance does not change, although lung volume needs to be increased
  • increased airway resistance due to bronchospasm
  • FEV reduced more than FVC