Nitric oxide diffusing capacity and alveolar microvascular recruitment in sarcoidosis

Anagha R. Phansalkar, Chad M. Hanson, Ahmed R. Shakir, Robert L. Johnson, Connie C W Hsia

Research output: Contribution to journalArticle

50 Scopus citations

Abstract

We measured diffusing capacities for carbon monoxide (DLco) and nitric oxide, lung volume, and cardiac output by a rebreathing technique at two alveolar O2 tensions (PAo2) at rest and exercise. Membrane diffusing capacity for CO (DMco) and Vc were estimated from DL co, by the Roughton-Forster (RF) method and also from simultaneous lung diffusing capacity for NO and Dkco measured at one O2 tension (modified RF method). Estimates by these methods agreed closely in normal subjects (Tamhane et al., Chest 2001; 120:1850-1856). Using these methods, we studied patients with stages II-III pulmonary sarcoidosis to determine (1) whether the modified RF method accurately estimates DM co and Vc in parenchymal disease and (2) whether sarcoidosis alters recruitment of diffusing capacity with respect to cardiac output. In patients, DMco and Vc estimated by the two methods agreed closely. DMco was disproportionately reduced relative to Vc at any given cardiac output, and the slope of the relationship between DLco and cardiac output was moderately, though significantly, below normal. We conclude that in sarcoidosls (1) the modified RF method provides comparable estimates of DMco and Vc as the standard RF method and (2) the limitation to diffusive gas transport resides primarily in the membrane barrier, although recruitment of microvascular reserves is also modestly impaired.

Original languageEnglish (US)
Pages (from-to)1034-1040
Number of pages7
JournalAmerican journal of respiratory and critical care medicine
Volume169
Issue number9
StatePublished - May 1 2004

Keywords

  • Capillary blood volume
  • Exercise
  • Membrane diffusing capacity
  • Nitric oxide
  • Roughton-forster relationship

ASJC Scopus subject areas

  • Pulmonary and Respiratory Medicine
  • Critical Care and Intensive Care Medicine

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