China Science

Hlastala,MP; Anderson,JC

Abstract Highly soluble gases exchange primarily with the bronchial circulationthrough pulmonary airway tissue. Because of this airway exchange, the assumption that end-exhaledalcohol concentration (EEAC) is equal to alveolar alcohol concentration (AAC) cannot be true. Duringexhalation, breath alcohol concentration (BrAC) decreases due to uptake of ethanol by the airwaytissue. It is therefore impossible to deliver alveolar gas to the mouth during a single exhalationwithout losing alcohol to the airway mucosa. A consequence of airway alcohol exchange is that EEACis always less than AAC. In this study, we use a mathematical model of the human lung to determinethe influence of subject lung size on the relative reduction of BrAC from AAC. We find that failureto inspire a full inspiration reduces the BrAC at full exhalation, but increases the BrAC at minimumexhalation. In addition, a reduced inhaled volume and can lead to an inability to provide anadequate breath volume. We conclude that alcohol exchange with the airways during thesingle-exhalation breath test is dependent on lung size of the subject with a bias against subjectswith smaller lung size.

Keywords Breath Tests; Ethanol; Lung; Models, Biological; Respiratory Mechanics; TidalVolume

Annals of Biomedical Engineering
0090-6964, Volume 35, Issue 2, 2007, Pages 3-272