Fate of air emboli in the pulmonary circulation

R. G. Presson*, K. R. Kirk, K. A. Haselby, J. H. Linehan, S. Zaleski, W. W. Wagner

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

42 Scopus citations


The lung serves an important nonrespiratory function by trapping and excreting venous air emboli. The site of trapping and the mechanism of excretion, however, are uncertain. To observe the behavior of bubbles in the pulmonary circulation, we injected venous air emboli into anaesthetized dogs and videotaped their elimination from the pulmonary microcirculation by using in vivo microscopy. Small intravenous bubbles lodged exclusively in pulmonary arterioles and were eliminated from that site. To determine whether the gas was dissolving into nearby blood and then was carried to the capillaries for excretion, the rate of bubble radius change was measured during nonperfused conditions produced by balloon occlusion of lobar blood flow and compared with perfused and nonperfused conditions. Bubble volume decreased at the same rate during perfused and nonperfused conditions and thus was independent of regional blood flow. Molecular diffusion of gas directly across the arteriolar wall into alveolar spaces was the most likely mechanism of elimination because calculations based on the Fick equation for molecular diffusion predict an elimination rate nearly identical with those observed experimentally.

Original languageEnglish (US)
Pages (from-to)1898-1902
Number of pages5
JournalJournal of applied physiology
Issue number5
StatePublished - 1989


  • Pulmonary air embolism
  • in vivo microscopy
  • molecular diffusion
  • precapillary gas exchange
  • surface tension
  • venous air embolism

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)


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