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DISPERSION OF AEROSOL BOLUSES IN THE HUMAN LUNG: DEPENDENCE ON LUNG VOLUME, BOLUS VOLUME, AND GENDER
Citation:
Brown, J., T. Gerrity, W. Bennett, C. Kim, AND D. House. DISPERSION OF AEROSOL BOLUSES IN THE HUMAN LUNG: DEPENDENCE ON LUNG VOLUME, BOLUS VOLUME, AND GENDER. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/J-95/554.
Description:
The dispersion of aerosol boluses in the human lungs has been studied in health and disease by other investigators as a means of investigating convective mixing. owever, there are only limited data on the roles played in dispersion by critical factors such as the volume of inhaled boluses, lung inflation, and gender. o examine these factors we measured the difference in volume variance between exhaled and inhaled boluses (ov2) of a 0.5 um aerosol in 11 healthy male and 12 healthy female subjects as a function of tidal volume (Vt = 1000 and 1500 mi in females, and 1000 and 2000 ml in males), bolus penetration volume (V at 250 ml increments over each Vt), and bolus volume (Vbol = 75, 150, and 300 ml). he av was increased in males compared to females (p<0.001). here was also a significant effect of Vbol on aV2 (p<0.001). A shift in the mean volume between inhaled and exhaled boluses (AV) was observed at all Vi except 500 ml. he observation of gender and Vbol effects and the existence of a non-zero AV suggest convective mixing mechanisms other than longitudinal dispersion alone occur in the healthy lung. he lack of Vt dependence suggests a minimal role of lung inflation above FRC on dispersion. he dependence of av2 on V2 up to 1750 ml and minimal Vbol demonstrates that convective mixing processes continue far into the gas exchange regions of the lung and support a significant role for axial streaming.