Ventilation inhomogeneity, as assessed by the regional distribution of 133Xe and the single breath washout (SBW) curve, is compared with the morphologic aspects in excised human lungs. Morphologic measurements include central airway diameter, bronchial gland area, peripheral airway diameter, and the alveolar surface-to-volume ratio. Lung inflation with a constant concentration of 133Xe results in the relatively more 133Xe distributed to the lung base than to the apex. Neither the vertical gradient in ventilation nor other interregional inhomogeneities in 133Xe distribution are correlated with morphologic variations in the lung. Also, interregional inhomogeneities of 133Xe distribution do not correlate with phase II slope of the SBW curve. This suggests that the phase II sloop is determined primarily by intraregional ventilation inhomogeneities. Within the phase IV region of SBW curve two distinct inflections are identified: an inflection at volume V1 and another sharper inflection at volume V2. Both the phase III slope and V2 correlate significantly (p < 0.05) with peripheral airway diameter, indicating that parameters of the SBW curve do assess peripheral airway properties.
|Original language||English (US)|
|Number of pages||5|
|Journal||American Review of Respiratory Disease|
|State||Published - Jan 1 1982|