Ageing of the lung parenchyma

Introduction The study of lung parenchymal function is focused on the measurement of carbon monoxide diffusing transfer (TLCO) which is a function of both membrane characteristics (Dm) and capillary lung volume (Vc) The objective of this study was to estimate the effect of age on both variables. Methods At rest, 134 healthy non-smokers (18-85 year old) were investigated by a double transfer NO-CO method. Capillary pulmonary compliance was estimated by applying a continuous negative pressure (CNP: -10 mmHg) at the mouth to 24 subjects. Results Significant decreases in VA, TLCO, TLNO, Dm and Vc in relation to age were observed (p < 0.05). CNP induced a significant increase in all variables, the increase in Vc in elderly was greater than that in younger subjects. Conclusion Alveolo capillary membrane ageing induces a decrease in Dm and Vc, however the increase in the estimated capillary compliance with CNP could provide an adaptation to the decrease in Vc.