Progression of PFTs
The total number of PFTs was different for each patient (median 6; range:2-17). At each PFTs, FVC, FEV1, FEV1/FVC and MMEF25%-75% were all performed in all patients. The median time interval between each PFTs was 9 months (range: 1-35 months). There was significant inter- and intra-individual variability in every PFT parameter over time (Figure 2). However, even after taking that into account, over time, the FVC and FEV1 improved in eleven children and was only mild decrease in one child, FVC and FEV1 increased by a mean of 8.212%/year (95% CI: 6.531%-9.894%; p<0.0001) and 5.007%/year (95% CI: 3.463%-6.552%; p<0.0001) (Table 2, Figure 2). But the increase in FEV1 was not as significant as FVC, so there was a unanimous and significant fall in FEV1/FVC ratio with an average decrease of 3.537%/year (95% CI: 1.984%-5.09%; p<0.0001) (Table 2, Figure 2). MMEF25%-75% improved in nine children and unchanged or declined slightly in three children, resulting in an average increase of 1.583% per year (95% CI: 0.046%-3.12%; p<0.05) (Table 2, Figure 2).
Over all, FEV1 and MMEF25%-75% showed different degrees of improvement after inhaled bronchodilators at each PFT sessions for ten patients, and FEV1 was with significant (>12%) β2-bronchodilation in 53% of PFT sessions. (Figure 2, data was not given).