Bronchodilator response
A positive spirometric BDR was detected in 7 patients (19.4% of total),
who presented a mean increase in FEV1 on baseline of 18.71% ± 5.91.
Mean percentual changes on baseline of oscillometric parameters R5 and
X5 differed significantly between patients with positive and negative
spirometric BDR (Table 3). Patients with a positive BDR showed a
decrease of 26.82% ± 6.58 in R5 whereas those with a negative BDR
showed a decrease of 18.18% ± 10.08 for the same parameter (p = 0.03).
Similarly, the increase in X5 resulted of 34.3% ± 9.83 and 20.59% ±
18.43 in subjects with a positive and a negative BDR, respectively (p =
0.04).
The Mann-Whitney U-test highlighted no significant differences in
baseline IOS parameters between BDR-positive and BDR-negative patients
(Table 4); furthermore, no significant differences emerged in clinical
characteristics (age, atopy, TRACK score, taking of control
medications). The modifications in all analyzed parameters for
spirometry and IOS in all patients after BDR test are summarized in
Table 5. All post-bronchodilation values were significantly different in
relation to the respective pre-bronchodilation for all analysed indexes.
The mean modifications on baseline of main IOS parameters were -19.86%
± 10.04 (p<0.0001) in R5, 23.25% ± 17.85 (p<0.0001)
in X5, and -44.63% ± 22.1 (p<0.0001) in AX.
After bronchodilator administration, the correlation between FEV1 and
R5, X5 and AX was good only for R5 (ρ=-0.64; p<0.0001),
whereas resulted moderate for X5 (ρ=0.42; p=0.01) and AX (ρ=-0.44;
p=0.007). Finally, in assessing BDR, no significant correlation was
found between FEV1 and all analyzed IOS parameters in terms of
percentual change on baseline.