BACKGROUND: The alveolar volume (V(A)), determined by single-breath helium dilution, is a measure for the total lung capacity (TLC) that is very sensitive to ventilatory disturbances. In chronic obstructive pulmonary disease (COPD), the emphysematous lung parts are less accessible to test gas; therefore, the V(A) is smaller than TLC measured by multiple-breath helium dilution (TLC(He)). OBJECTIVES: The aim of this study was to investigate whether the V(A) represents the nonemphysematous lung parts. METHODS: We measured V(A) as part of the diffusing capacity for carbon monoxide (DL(CO)), TLC(He) and spirometry in 50 patients with COPD. High-resolution computed tomography (HRCT) scans of all subjects were analyzed with the density mask method, where parts with an attenuation of less than -950 Hounsfield units were considered as emphysematous. RESULTS: A strong correlation was observed between the V(A) (mean 5.2 liters) and nonemphysematous HRCT lung volume (mean 5.2 liters, r(2) = 0.9) and between the TLC(He) (mean 6.6 liters) and total HRCT lung volume (mean 6.4 liters, r(2) = 0.9). Bland-Altman plots showed considerable disagreement between the V(A) and the nonemphysematous HRCT lung volume. A weak correlation between the forced expiratory volume in 1 s (mean 46% predicted) and DL(CO) (mean 46% predicted) versus the HRCT emphysema ratio (nonemphysematous/total HRCT lung volume) was observed (r(2) = 0.3 and 0.3, respectively). CONCLUSION: We concluded that the V(A) correlates with the nonemphysematous HRCT lung volume, although the two measurements are not equivalent, possibly due to technical factors.
BACKGROUND: The alveolar volume (V(A)), determined by single-breath helium dilution, is a measure for the total lung capacity (TLC) that is very sensitive to ventilatory disturbances. In chronic obstructive pulmonary disease (COPD), the emphysematous lung parts are less accessible to test gas; therefore, the V(A) is smaller than TLC measured by multiple-breath helium dilution (TLC(He)). OBJECTIVES: The aim of this study was to investigate whether the V(A) represents the nonemphysematous lung parts. METHODS: We measured V(A) as part of the diffusing capacity for carbon monoxide (DL(CO)), TLC(He) and spirometry in 50 patients with COPD. High-resolution computed tomography (HRCT) scans of all subjects were analyzed with the density mask method, where parts with an attenuation of less than -950 Hounsfield units were considered as emphysematous. RESULTS: A strong correlation was observed between the V(A) (mean 5.2 liters) and nonemphysematous HRCT lung volume (mean 5.2 liters, r(2) = 0.9) and between the TLC(He) (mean 6.6 liters) and total HRCT lung volume (mean 6.4 liters, r(2) = 0.9). Bland-Altman plots showed considerable disagreement between the V(A) and the nonemphysematous HRCT lung volume. A weak correlation between the forced expiratory volume in 1 s (mean 46% predicted) and DL(CO) (mean 46% predicted) versus the HRCT emphysema ratio (nonemphysematous/total HRCT lung volume) was observed (r(2) = 0.3 and 0.3, respectively). CONCLUSION: We concluded that the V(A) correlates with the nonemphysematous HRCT lung volume, although the two measurements are not equivalent, possibly due to technical factors.
Authors: Fulvia Milite; David J Lederer; Jeremy A Weingarten; Pauline Fani; Anne M Mooney; Robert C Basner Journal: Respir Physiol Neurobiol Date: 2008-12-25 Impact factor: 1.931
Authors: Dinis Reis Miranda; Lennart Klompe; Filippo Cademartiri; Jack J Haitsma; Alessandro Palumbo; Johanna J M Takkenberg; Burkhard Lachmann; Ad J J C Bogers; Diederik Gommers Journal: Crit Care Date: 2006-06-08 Impact factor: 9.097
Authors: Anna Winkler; Kathrin Kahnert; Jürgen Behr; Claus Neurohr; Nikolaus Kneidinger; Rudolf Hatz; Holger Dressel; Thomas Radtke; Rudolf A Jörres Journal: Respir Res Date: 2018-09-10