Tracheal gas exchange: Perfusion-related differences in inert gas elimination

J. E. Souders, Steven George, N. L. Polissar, E. R. Swenson, M. P. Hlastala

Research output: Contribution to journalArticle

18 Scopus citations

Abstract

Exchange of inert gases across the conducting airways has been demonstrated by using an isolated dog tracheal preparation and has been characterized by using a mathematical model (E. R. Swenson, H. T. Robertson, N. L. Polissar, M. E. Middaugh, and M. P. Hlastala. J. Appl. Physiol. 72: 1581-1588, 1992). Theory predicts that gas exchange is both diffusion and perfusion dependent, with gases with a higher blood-gas partition coefficient exchanging more efficiently. The present study evaluated the perfusion dependence of airway gas exchange in an in situ canine tracheal preparation. Eight dogs were studied under general anesthesia with the same isolated tracheal preparation. Tracheal perfusion (Q̇) was altered from control blood flow (Q̇0) by epinephrine or papaverine instilled into the trachea and was measured with fluorescent microspheres. Six inert gases of differing blood- gas partition coefficients were used to measure inert gas elimination. Gas exchange was quantified as excretion (E), equal to exhaled partial pressure divided by arterial partial pressure. Data were plotted as ln [E/(1 - E)] rs. In (Q̇/Q̇0), and the slopes were determined by least squares. Excretion was a positive function of Q̇, and the magnitude of the response of each gas to changes in Q̇ was similar and highly significant (P ≤ 0.0002). These results confirm a substantial perfusion dependence of airway gas exchange.

Original languageEnglish (US)
Pages (from-to)918-928
Number of pages11
JournalJournal of Applied Physiology
Volume79
Issue number3
DOIs
StatePublished - Jan 1 1995
Externally publishedYes

Keywords

  • airways
  • bronchial circulation
  • diffusion coefficient in tissue
  • diffusion limitation
  • gas phase

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

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