In vivo characterization of the transitional bronchioles by aerosol-derived airway morphometry

• Published in: Journal of applied physiology (1985) 1999-09, Vol.87 (3), p.920-927
• Main Authors: Zeman, Kirby L, Scheuch, Gerhard, Sommerer, Knut, Brown, James S, Bennett, William D
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Aerosols; Aged; Aged, 80 and over; Aging - physiology; Air breathing; Biological and medical sciences; Bronchi - anatomy & histology; Bronchi - growth & development; Bronchi - physiology; Child; Female; Forced Expiratory Volume - physiology; Fundamental and applied biological sciences. Psychology; Humans; Lung - anatomy & histology; Lung - growth & development; Lung Volume Measurements; Lungs; Male; Middle Aged; Respiratory diseases; Respiratory system: anatomy, metabolism, gas exchange, ventilatory mechanics, respiratory hemodynamics; Sex Characteristics; Total Lung Capacity - physiology; Vertebrates: respiratory system
• ISSN: 8750-7587; 1522-1601
• DOI: 10.1152/jappl.1999.87.3.920

1  Center for Environmental Medicine and Lung Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599; and 2  GSF-National Research Center for Environment and Health, Institute for Inhalation Biology, D-85758 Neuherberg/Munich, Germany Effective airway dimensions (EADs) were determined in vivo by aerosol-derived airway morphometry as a function of volumetric lung depth (VLD) to identify and characterize, noninvasively, the caliber of the transitional bronchiole region of the human lung and to compare the EADs by age, gender, and disease. By logarithmically plotting EAD vs. VLD, two distinct regions of the lung emerged that were identified by characteristic line slopes. The intersection of proximal and distal segments was defined as VLD trans and associated EAD trans . In our normal subjects ( n  = 20), VLD trans [345 ± 83   (SD) ml] correlated significantly with anatomic dead space (224   ± 34 ml) and end of phase II of single-breath nitrogen washout (360 ± 53 ml). The corresponding EAD trans was 0.42 ± 0.07 mm, in agreement with other ex vivo measurements of the transitional bronchioles. VLD trans was smaller (216 ± 64 ml) and EAD trans was larger (0.83 ± 0.04 mm) in our patients with chronic obstructive pulmonary disease ( n  = 13). VLD trans increased with age for children (age 8-18 yr; P  = 0.006,  n  = 26) and with total lung capacity for age 8-81 yr ( P