The single-breath N2-test and spirometry in healthy non-smoking males.
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.
D000328:Adult; D000368:Aged; D003011:Closing Volume; D005541:Forced Expiratory Volume; D006801:Humans; D008297:Male; D008875:Middle Aged; D009584:Nitrogen; D012016:Reference Values; D013147:Spirometry / Q000379:methods*; D014797:Vital Capacity
D009584:Nitrogen