Sex and age differences in intrathoracic airways mechanics in normal man

Abstract

Expiratory pressure-volume curves and maximal expiratory flow-volume curves were obtained in 74 healthy subjects (49 males 25 females) aged between 20 and 64. Maximal expiratory flowstatic recoil (MEFSR) curves were then constructed. Aging was associated with loss of lung recoil and reduction in maximal expiratory flow measured between 80 and 50% total lung capacity (TLC), in both males and females, with the slope of the MEFSR curve becoming steeper. In subjects less than 40 yr old the conductance of the upstream segment increased from 80 to 50% TLC, whereas in older subjects it decreased. We also studied the effects of alveolar gas compression artifacts on MEFSR curves in 12 additional subjects and 10 patients with chronic obstructive lung disease; consistent changes were found, but the subsequent shift of the MEFSR curve toward the left was only mild. These changes are interpreted as reflecting the net effects of an increase in the unstressed dimensions of the airways together with a decrease in intraparenchymal airways diameter, probably due to loss of parenchymal airways diameter, probably due to loss of parenchymal support. It was also concluded that the analysis of the MEFSR curve did not allow a quantitative estimate of the chantes in airways compressibility with aging.

Physiological and morphological determinants of maximal expiratory flow in chronic obstructive lung disease

“…In agreement with the study of YERNAULT et al [31], Gus(pred) and Ptm'(pred) increased with age and were higher for males than for females. An increase in Gus with age has been described by a number of authors [31,[42][43][44]. The decrease of maximal flows at fixed lung volumes, with increasing age, is predominantly related to decreased lung elastic recoil pressure.…”

“…Finally, we did not find an increase of Ptm' with age, as was predicted by our reference values. The increase in Ptm'(pred) is in agreement with the study by YERNAULT et al [31], who found an increase of Ptm' versus age in a group of 74 healthy subjects. But, as was stated by these authors, a number of studies showed that airway compliance decreases with age [32,33].…”

“…We calculated predicted values for Gus and Ptm' (Gus(pred) and Ptm'(pred)) for each patient using reference values both for elastic recoil pressure and maximal expiratory flows [11,14]. In agreement with the study of YERNAULT et al [31], Gus(pred) and Ptm'(pred) increased with age and were higher for males than for females. An increase in Gus with age has been described by a number of authors [31,[42][43][44].…”

“…In these studies, patients were compared to a limited number of healthy subjects, without matching for age or sex. YERNAULT et al [31] described an increase in Gus with age that was comparable for males and females. Gus was higher in males than in females.…”

Age and Sex Dependence of Forced Expiratory Central Airway Collapse in Healthy Volunteers

“…Lung elastic recoil at a given volume is reduced with aging in both men and women. [15][16][17][18] While this alone might result in smaller airway cross section at a given lung volume due to loss of tethering support from the lung parenchyma, Mead et al 19 suggested that increases in the resting dimensions of airways with age might offset any tendency for reduced airway cross section related to decreased parenchymal tethering, thus preserving maximal expiratory fl ow. Indeed, Gibellino et al, 14 using chest radiographs to study tracheal characteristics in a large sample of healthy men and women, found that age-associated increase in tracheal dimension at high lung volume is relatively greater than the corresponding loss of lung elastic recoil.…”