title: Breath ethyl alcohol concentration and analysis in the presence of chronic obstructive pulmonary disease.
abstract: We have made continuous measurements of exhaled ethanol concentration vs volume during slow expiration in subjects with plasma ethanol concentrations up to 700 mg/L. Subjects included individuals with normal pulmonary function and those with severe chronic obstructive pulmonary disease (COPD). In addition to the measurements of breath ethanol made using a flame ionization detector, paired measurements were also made of plasma ethanol and breath ethanol using a Model 900A Breathalyser. In normal subjects, the breath ethanol concentration was found to increase continuously during expiration until the very end of the expiration when a decline in concentration was noted. In the presence of COPD the ethanol concentration/volume tracing was essentially flat during the middle portion of expiration, but many subjects showed a decrease in concentration at the end of the expiration. One subject showed a sharp rise in breath concentration at the end of expiration. The results suggest that fluctuations in the ethanol concentration are caused by variation in the ventilation/perfusion ratio of regions of the lung supplying the expirate, and that breath with ethanol in equilibrium with the plasma is not routinely obtained, especially at the end of a maximal expiration. Thus, exhaled air at the end of maximal expiration does not always provide the best, or a close, indication of the plasma (or blood) ethanol concentration. The peak breath ethanol concentrations found were, as an equivalent plasma concentration, = -25 + 0.924 X plasma ethanol, mg/L. The Breathalyser readings = -45 + 0.898 X plasma ethanol, mg/L, with a mean difference of -81 mg/L.
mesh_terms: D000328:Adult; D000368:Aged; D001944:Breath Tests; D000431:Ethanol / Q000032:analysis* / Q000097:blood; D006801:Humans; D008173:Lung Diseases, Obstructive / Q000097:blood / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D014692:Ventilation-Perfusion Ratio
chemical_list: D000431:Ethanol