Airway reopening pressure in isolated rat lungs

E. T. Naureckas, C. A. Dawson, B. S. Gerber, D. P. Gaver, H. L. Gerber, J. H. Linehan, J. Solway, R. W. Samsel*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

66 Scopus citations


In a previous modeling study, we predicted that the yield pressure for airway reopening (Pyield) should depend on airway fluid surface tension (γ) and airway radius (R), according to the relationship Pyield = 8.3γ/R. To test this prediction, we studied tantalum bronchograms of isolated perfused rat lungs from three rats by using microfocal X-ray imaging. Thirty-two airways with diameters ranging from 300 to 2,400 μm were recorded as the airways were collapsed and reinflated. Airway pressure was reduced transiently to -40 cmH2O to produce airway closure. Airway pressure was then slowly increased from 0 to 25 cmH2O. In each airway, the observed diameter remained constant until a Pyield was reached; at this pressure, airways were seen to 'pop' open, allowing clear identification of airway reopening pressure. When Pyield was plotted against diameter at maximum inflation, the experimental data were in approximate agreement with predictions of Pyield made assuming a γ of 35 dyn/cm. The close correspondence of the measured values with these predictions suggests that surfactant is present in these airways and facilitates airway reopening.

Original languageEnglish (US)
Pages (from-to)1372-1377
Number of pages6
JournalJournal of applied physiology
Issue number3
StatePublished - 1994


  • airway closure
  • surface tension
  • yield pressure

ASJC Scopus subject areas

  • Physiology (medical)
  • Physiology


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