The single-breath N2-test and spirometry in healthy non-smoking males

Eur J Respir Dis. 1984 May;65(4):296-304.


Healthy males (aged 30-70), who had never smoked, were studied. The 178 subjects were selected by systematic sampling from an urban population. Using the single-breath N2-washout test we measured the closing volume (CV) and the slope of the alveolar plateau (delta N2). A prediction equation for CV was produced by simple regression on age. delta N2 showed an accelerated increase with age above the age of 50. A curvilinear equation was established: delta N2 (%/1) = 0.85 + e0.0929 x A( yrs ) -6.302. Reference equations were also established for vital capacity (VC), forced expiratory volume in one second (FEV1) and FEV1 in per cent VC (FEV%) by means of linear multiple regression on age and height. The distribution of delta N2 was not homogenous throughout the age-range. As an upper limit of the reference range, we suggest 180% of the predicted value.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Closing Volume
  • Forced Expiratory Volume
  • Humans
  • Male
  • Middle Aged
  • Nitrogen*
  • Reference Values
  • Spirometry / methods*
  • Vital Capacity


  • Nitrogen