Acinar and conductive ventilation heterogeneity in severe CF lung disease: back to the model

Respir Physiol Neurobiol. 2013 Aug 15;188(2):124-32. doi: 10.1016/j.resp.2013.05.011. Epub 2013 May 18.


Severe convective ventilation heterogeneity occurring in CF lung disease requires a modified method to determine acinar and conductive components of ventilation heterogeneity from normalized phase III slope (Sn) curves. Modified Sacin* and Scond* (as opposed to standard Sacin and Scond) are proposed and interpreted on the basis of 2 conceptual mechanisms: (a) flow asynchrony between two convection-dependent units with a different specific ventilation, but with an identical acinus inside each unit (generating an identical diffusion-convection-dependent portion of Sn); (b) different specific ventilation (without any flow asynchrony) between two convection-dependent units with the worst ventilated unit containing an abnormal acinus generating the greatest diffusion-convection-dependent portion of Sn. In CF patients with an abnormal lung clearance index (LCI), Scond* (but not Scond) and Sacin* were significant contributors to LCI (β(Scond*)=0.70; β(Sacin*)=0.49; P<0.001 for both). Mechanism (a) can entirely account for experimental Scond* values, while mechanism (b) implies that experimental Sacin* values are likely dominated by peripheral ventilation heterogeneity in the best ventilated portions of the lung.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Anthropometry
  • Bronchial Provocation Tests
  • Case-Control Studies
  • Computer Simulation
  • Cystic Fibrosis / complications*
  • Female
  • Humans
  • Lung / pathology
  • Lung Diseases / diagnosis*
  • Lung Diseases / etiology*
  • Male
  • Models, Biological*
  • Pulmonary Ventilation / physiology*
  • Young Adult