Elastic properties of the centrilobular emphysematous space

Abstract

Bronchograms were performed using finely particulate lead on emphysematous lungs obtained at necropsy. X-ray films were taken of these lungs at distending pressures of 0, 5, 10, and 20 cm H₂O. The volumes of individual centrilobular emphysematous spaces were calculated at each distending pressure from measurements made on these bronchograms and pressure-volume curves were constructed for each space. The pressure-volume characteristics of seven normal lungs and one lung with centrilobular emphysema was also measured. The normal lungs, the lung with centrilobular emphysema, and the centrilobular emphysematous spaces were compared by expressing the volume of air contained in them at each distending pressure as a per cent of the volume contained at 20 cm H₂O distending pressure. We conclude that centrilobular emphysematous spaces have a high residual volume, are less compliant than normal lung tissue, and are much less compliant than the emphysematous lungs which contain them. Furthermore, these spaces undergo little volume change in the tidal breathing range and probably add a relatively nondistensible series dead space to the surrounding lung parenchyma.