Noninvasive measures of lung structure and ventilation heterogeneity

Airway function at different lung depths can be determined non-invasively via ventilation distribution tests, by measuring either gases or aerosols at the mouth. After having a subject inhale a well-characterized amount of gas or aerosol in a well-controlled breathing maneuver, the expired gas or aerosol trace can be analyzed to represent critical structural and functional features of the lung. One such feature is the asymmetry of the lung, both in terms of its ramification pattern and expansion characteristics, in the conductive and acinar lung zone. We discuss how these features will affect gas and aerosol behavior in specific ways, based on conceptual models and quantitative simulations where possible. This should help interpret non-invasive tests of ventilation distribution and recognize their pitfalls.SCOPUS: ch.binfo:eu-repo/semantics/publishe