Eighteen asthmatic children were challenged with ultrasonically
nebulized cold distilled water (UNCDW). Blood gas composition was
monitored transcutaneously (tcpO2 and tcpCO2)
during and after the challenge. Assuming as basal the response to
this UNCDW test, nine children (Group A) were then chosen at random
to inhale cromoglycate by aerosol delivery for 8 days. Nine children
(Group B), acting as a control, inhaled saline for 8 days. At the
end of this therapy, each child repeated the UNCDW test. Statistical
analysis with t-test for paired data was used to compare the results
of each child to both tests. Mean basal tcpO2 and
tcpCO2 were all within the expected normal range. In all
children, both mean tcpO2 and tcpCO2 were
reduced during and after UNCDW inhalation. Mean tcpCO2
values during the challenge were significantly (p<0.001) lower than the corresponding steady state 2 rain after the UNCDW
challenge, with a mean drop of −7% (2.1 S.D.). Mean
tcpO2 values remained significantly decreased
(p<0.001) from the fifth mitt of the UNCDW challenge to the end of the
observation period, with a mean drop of −20% (15.5
S.D.). After treatment with cromoglycate (Group A), the mean
tcpCO2 values during UNCDW did not change significantly
from those ofsteady state conditions: −0.8% (0.5 S.D.);
whereas mean tcpO2 values decreased by −4%
(4.9 S.D.). The control children treated with saline (Group B)
showed mean tcpCO2 and tcpO2 values which were
significantly different (p<0.001) from those of the steady
state conditions: mean drop of tcpCO2, −6%
(4.2 S.D.); mean drop of tcpO2, −20% (4.7
S.D.). In conclusion, it emerges that: UNCDW induces nonspecific
broncho-constriction in asthmatic children with a typical drop of
tcpCO2 and tcpO2; the treatment with
cromoglycate normalizes the time course of tcpCO2
(hyper-reactivity) and reduces dramatically the drop of
tcpO2 time course (hyper-responsivity) during and after
the UNCDW test.
