Objectives: To compare the acceptability,
reproducibility, and sensitivity of spirometric outcome measures of
airway caliber during challenge testing in children.
Design: FEV1, forced expiratory volume in
0.75 s, forced expiratory volume in 0.5 s, and peak
expiratory flow (PEF) were recorded during stepwise dosimetric
histamine challenge tests. The responses were compared, and the
reproducibility at baseline and from duplicate measurements at each
challenge step was determined.
Patients: One hundred
five children with newly diagnosed asthma, aged 5 to 10 years.
Results: Compared to PEF, FEV1 showed better
baseline reproducibility (p = 0.002) and higher sensitivity
(p < 0.0001) during challenge testing, determined as the change
normalized to the baseline variation, while the forced expiratory
volumes were not significantly different in these respects. During
challenge testing in subjects with acceptable flow-volume tracings,
paired recordings of FEV1 agreed within 0.1 L in 85% and
within 0.2 L in 93% of measurements. During challenge testing, the
reproducibility of FEV1 measurements was not better than
that of the other indexes. Failure to exhale long enough precluded the
use of FEV1 in 16 of the children, particularly the
Conclusions: The results
demonstrated that the recently published guidelines for
FEV1 measurements during challenge tests can be applied to
children. During challenge tests in asthmatic children, the advantage
of the shorter fractions of forced expiratory volume was that they were
more often acceptably recorded than FEV1, while they showed
as good reproducibility and were also equally sensitive in assessing
changes in airway obstruction.