Sequential V̇A/Q̇ distributions in the normal rabbit by micropore membrane inlet mass spectrometry

J. E. Baumgardner, I. C. Choi, A. Vonk-Noordegraaf, H. F. Frasch, G. R. Neufeld, B. E. Marshall

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We developed micropore membrane inlet mass spectrometer (MMIMS) probes to rapidly measure inert-gas partial pressures in small blood samples. The mass spectrometer output was linearly related to inert-gas partial pressure (r2 of 0.996-1.000) and was nearly independent of large variations in inert-gas solubility in liquid samples. We infused six inert gases into five pentobarbital-anesthetized New Zealand rabbits and used the MMIMS system to measure inert-gas partial pressures in systemic and pulmonary arterial blood and in mixed expired gas samples. The retention and excretion data were transformed into distributions of ventilation to-perfusion ratios (V̇(A)/Q̇) with the use of linear regression techniques. Distributions of V̇(A)/Q̇ were unimodal and broad, consistent with prior reports in the normal rabbit. Total blood sample volume for each V̇(A)/Q̇ distribution was 4 ml, and analysis time was 8 min. MMIMS provides a convenient method to perform the multiple inert-gas elimination technique rapidly and with small blood sample volumes.

Original languageEnglish
Pages (from-to)1699-1708
Number of pages10
JournalJournal of Applied Physiology
Issue number5
Publication statusPublished - 1 Jan 2000


  • Inert gases
  • Multiple inert-gas elimination technique
  • Solubility
  • Stirring effect

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