Mechanics of edematous lungs

Theodore A. Wilson, Ron C. Anafi, Rolf D. Hubmayr

Research output: Contribution to journalArticlepeer-review

60 Scopus citations


Using the parenchymal marker technique, we measured pressure (P)-volume (P-V) curves of regions with volumes of ∼1 cm3 in the dependent caudal lobes of oleic acid-injured dog lungs, during a very slow inflation from P = 0 to P = 30 cmH2O. The regional P-V curves are strongly sigmoidal. Regional volume, as a fraction of volume at total lung capacity, remains constant at 0.4-0.5 for airway P values from 0 to ∼20 cmH2O and then increases rapidly, but continuously, to 1 at P = ∼25 cmH2O. A model of parenchymal mechanics was modified to include the effects of elevated surface tension and fluid in the alveolar spaces. P-V curves calculated from the model are similar to the measured P-V curves. At lower lung volumes, P increases rapidly with lung volume as the air-fluid interface penetrates the mouth of the alveolus. At a value of P = ∼20 cmH2O, the air-fluid interface is inside the alveolus and the lung is compliant, like an air-filled lung with constant surface tension. We conclude that the properties of the P-V curve of edematous lungs, particularly the knee in the P-V curve, are the result of the mechanics of parenchyma with constant surface tension and partially fluid-filled alveoli, not the result of abrupt opening of airways or atelectatic parenchyma.

Original languageEnglish (US)
Pages (from-to)2088-2093
Number of pages6
JournalJournal of applied physiology
Issue number6
StatePublished - Jun 2001


  • Acute lung injury
  • Pressure-volume curve
  • Regional ventilation
  • Surface tension

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)


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