Baseline PFTs
Initial PFTs were accomplished at the age that each patient could
perform the maneuver (median:78 months; range: 59-110) according to the
guidelines established by the ATS/ERS. The median duration of the PIBO
disease at the time of initial PFTs was 43 months. All PFT data of
patients showed consistent with moderate to severe obstruction. At
baseline, the median PFT values (based on percentage of predicted value
for a given age) for FEV1, FVC, FEV1/FVC
ratio and MMEF25% -75% were 39.75%, 41.6%, 90.7%
and 22.2% respectively (Table 2).
Post-bronchodilator improvements were significant in expiratory flows,
although the values didn’t reach normality for age. Of the 12 pediatric
PIBO patients, 10 (83.3%) demonstrated a significant bronchodilator
response when the cut-off point was a percent change of 12%, as
recommended by the ATS/ERS (data was not given). As showed in Table 3,
FEV1 was significantly improved after inhalation of
bronchodilators, and MMEF25%-75% alike. The mean percent variation and
the mean absolute volume change from the previous measurement were
23.01% and 0.15 L for FEV1, 46.92% and 0.28L/s for
MMEF25%-75% respectively. In the multivariate analysis
of the outcome variables, we found that the predictor variables (age at
diagnosis, allergy factors) had no significant effect on the
bronchodilator response, although the higher diagnosis age will reduce
the improvement value of MMEF25%-75%(P<0.05) (Table 4).