XA MA N IC KE
LUING CLEAIL' 'NCE ','-7C'.1ANTSMS LZ INOM LN At D I - AVY S,,Z -RS
J. Sanchis Aldas, ".I. Dolovich, 0. Hopkins, R. Chalmers and.
1-1. T. Newhouse
In order to determine the effect of a heavy acute smoking exposure
on the pulmonary clearance mechanism, nine otherwise healthy non-bronchitic
smokers (over 15 ci-azattes daily) inhaled cigarettes at intervals of
15-30 minutes for approximately eight hours following inhalation of an
1 131 human serum albumin (IIHSA.) aerosol (mmass median diameter 3 p). The
distribution and clearance of inhaled IHSA was subsequently detecced and
followed at frequent intervals for up to 20 hours by means of an Anger
scintillation camara couDlcd to a 4096 channal pulse height analyzer
which allowed the lun- to be divided into approximately 100 areas 1.25
cm . The data was stored on magnetic tape for detailed quantitative
computer analysis. S.-..okers were compared to a similar group of healthy
nonismokers. For purposes of comparison data obtained from the lung was
averaged for three crescentic areas each 5 cms. wide arranged concentrically
about the hilus. L
.In smokers, overall lung clearance.was.more.rapid.than in normal
.@je@ts.
:Regional differences in clearance were quite marked, the inner or
perihilar (trachecobronchial) zone showing a slight accumulacion of activity
in the smok-ers for approxi:7ately two hours prior to the start of clearance,
with a T, of 30 minutes. In nonsmokers on the other hand, clearance of
radioactivity began i=ediately with a Tk of 36 minutes.
Th& most striking differences were noted in the intermediate zone,
where smokers had a T h of 2k hours, compared with the T in non-smokers
of six hours. In the most peripheral ragion, the Tk. for smokers and non-
a
smokers was 13@ and 40 hours respectively.
This data suggests that a heavy acute smoking exposure in otherwise
normal lun-s stimulates -.,ucociliary clearance. This is more marked
peripherally than in the hilar area. As a result, the clearance mechanism
which in normals ensures sequential removal of inhaled particles or drop-
lets from the periphery of the lun- to the trachea is disturbed dua to a
rqlativa ciliary inhibition in the region of the carina znd initial
bronchial branchings, which results in an inability to maintain sequential
clearin- of inhaled material. This "l ;.
@Lo Jam" effect may be an important
pathogenetic mechanism of chronic smokers' cough and it is also of interest
that it occurs in the lung at the site of highest incidence of bronchogenic
carcinoma.
S
A-17
N-0
d'..f4 :J
cr-%
BATCo document for Province of BritiSh Columbia 19 April 1999