Measurement of “closing volume” as a simple and sensitive test for early detection of small airway disease

Relationship between Frequency Dependence of Lung Compliance and Distribution of Ventilation

“…In our subjects, of two other tests which have been employed to detect small airway obstruction, the closing volume (23) showed no significant difference between nonsmokers and smokers, whereas maximum expiratory flow at 50% of vital capacity was significantly lower in smokers than in nonsmokers. However, the scatter of data minimizes the discriminatory value of this test in individual young smokers with small airway obstruction.…”

“…End-tidal N2 concentration was plotted against time (animals) and against cumulative expiratory volume (humans) and expressed as N2 clearance delay as described by Fowler et al (7). Corrections for the excretion of tissue nitrogen were made according to Simmons and Hemmingway (17) in dogs and Bouhuys (18) [22][23][24][25][26][27][28][29][30][31][32][33][34][35]. Seven smokers were asymptomatic, three gave a history of morning cough with sputum production, and one of these also had mild exertional dyspnea in the morning.…”

A Novel Interpretation of Closing Volume Based on Single-Breath Nitrogen Washout Curve Simulation

“…Burger and Macklem [6] demonstrated absorption atelectasis after 100% O 2 inspiration. Engel et al [4] and Hales et al [7] demonstrated the sequestration of alveolar air using N 2 0 and 13 N, respectively. However, none of their works identified the location of spatial disconnection.…”

“…In 1967, Dollfuss and Milic-Emili proposed a hypothesis that phase IV was due to airway closure in a dependent zone and named the volume fraction of phase IV to the vital capacity "closing volume" (CV) [2]. Furthermore, they reported a positive correlation of CV to age [3] and to smoking [4]. They speculated that small airways in aged people and in smokers were closed earlier than those in normal subjects and proposed that the measurement of CV was a simple and sensitive test for the early detection of small airway diseases [4].…”

“…Furthermore, they reported a positive correlation of CV to age [3] and to smoking [4]. They speculated that small airways in aged people and in smokers were closed earlier than those in normal subjects and proposed that the measurement of CV was a simple and sensitive test for the early detection of small airway diseases [4].…”