Bronchoscopic determination of ozone uptake in humans .
Gerrity, Timothy R., Frank Biscardi, Arthur Strong, Alan R.
Garlington, James S. Brown, Philip A. Bromberg.
USEPA Clinical Research Branch, Health Effects Research Laboratory
and University of North Carolina Center for Enviromental Medicine and
Lung Biology, Chapel Hill, NC, USA.
APStracts 2:0161A, 1995.
Measurements of ozone uptake efficiency in the human respiratory tract
provide critical information toward understanding ozone dose-response
characteristics. Toward this end we measured ozone uptake efficiency
by different regions of the respiratory tract between the mouth and
bronchus intermedius . Ten healthy, resting, non-smoking male and
female subjects underwent transnasal fiberoptic bronchoscopy while
supine inside a controlled exposure chamber containing 0.4 ppm ozone.
A bronchoscope was sequentially positioned at the bronchus
intermedius (BI), main carina (CAR), upper trachea (UT), and above
the vocal cords (LAR). Air samples at each location were drawn into a
rapidly responding ozone analyzer through a teflon catheter that was
inserted through the channel of the bronchoscope into the center of
the airway. During sampling subjects breathed through a mouthpiece
connected to a pneumotach at a paced rate of 12 breaths per minute.
Each measurement at each anatomic location was bracketed by two
measurements of airflow and ozone concentration at the mouth (M).
Integration of the product of the flow and ozone concentrations
during inspiration and expiration provided the ozone mass passing
each anatomic location during each phase of respiration. Since the
flow used for computation of mass at BI was the flow at the mouth,
the computed mass at BI represents the total ozone mass passing all
anatomically comparable locations. On inspiration the uptake
efficiency of ozone by structures between the mouth and each
location, j, (EM-j) were 0.176+/-0.037 (SE), 0.271+/-0.024, 0.355+/
-0.030, and 0.325+/-0.031 for LAR, UT, CAR, and BI respectively. A
significant effect of location on EM-j was found by analysis of
variance (p<0.0002). Pair-wise comparisons showed that EM-j
increased as the lung penetration increased except between CAR and BI
which were not significantly different.
Received 27 June 1994; accepted in final form 7 April 1995.
APS Manuscript Number A640-4.
Article publication pending Journal of Applied Physiology.
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 25 April 1995.