A rat lung model of instilled liquid transport in the pulmonary airways

K. J. Cassidy, J. L. Bull, M. R. Glucksberg, C. A. Dawson, S. T. Haworth, R. Hirschl, N. Gavriely, J. B. Grotberg*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

46 Scopus citations


When a liquid is instilled in the pulmonary airways during medical therapy, the method of instillation affects the liquid distribution throughout the lung. To investigate the fluid transport dynamics, exogenous surfactant (Survanta) mixed with a radiopaque tracer is instilled into tracheae of vertical, excised rat lungs (ventilation 40 breaths/min, 4 ml tidal volume). Two methods are compared: For case A, the liquid drains by gravity into the upper airways followed by inspiration; for case B, the liquid initially forms a plug in the trachea, followed by inspiration. Experiments are continuously recorded using a microfocal X-ray source and a imageintensifier, charge-coupled device image train. Video images recorded at 30 images/s are digitized and analyzed. Transport dynamics during the first few breaths are quantified statistically and follow trends for liquid plug propagation theory. A plug of liquid driven by forced air can reach alveolar regions within the first few breaths. Homogeneity of distribution measured at end inspiration for several breaths demonstrates that case B is twice as homogeneous as case A. The formation of a liquid plug in the trachea, before inspiration, is important in creating a more uniform liquid distribution throughout the lungs.

Original languageEnglish (US)
Pages (from-to)1955-1967
Number of pages13
JournalJournal of applied physiology
Issue number5
StatePublished - 2001


  • Drug delivery
  • Exogenous lung surfactant
  • Liquid bolus
  • Liquid ventilation
  • Respiratory distress syndrome
  • Surfactant replacement therapy

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)


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