15 research outputs found
Small airway dysfunction is associated to excessive bronchoconstriction in asthmatic patients
We investigated whether a relationship between small airways dysfunction and bronchial
hyperresponsiveness (BHR), expressed both in terms of ease of airway narrowing and of excessive
bronchoconstriction, could be demonstrated in asthma.
Methods: 63 (36 F; mean age 42 yr ± 14) stable, mild-to-moderate asthmatic patients (FEV1 92% pred ±14; FEV1/FVC
75% ± 8) underwent the methacholine challenge test (MCT). The degree of BHR was expressed as PD20 (in Όg) and as
ÎFVC%. Peripheral airway resistance was measured pre- and post-MCT by impulse oscillometry system (IOS) and
expressed as R5-R20 (in kPa sLâ1).
Results: All patients showed BHR to methacholine (PD20 < 1600 ÎŒg) with a PD20 geometric (95% CI) mean value
of 181(132â249) ÎŒg and a ÎFVC% mean value of 13.6% ± 5.1, ranging 2.5 to 29.5%. 30 out of 63 patients had
R5-R20 > 0.03 kPa sLâ1 (>upper normal limit) and showed ÎFVC%, but not PD20 values significantly different from the
33 patients who had R5-R20 †0.03 kPa sLâ1 (15.8% ± 4.6 vs 11.5% ± 4.8, p < 0.01 and 156(96â254) ÎŒg vs 207 (134â322) ÎŒg,
p = 0.382). In addition, ÎFVC% values were significantly related to the corresponding pre- (r = 0.451, p < 0.001) and
post-MCT (r = 0.376, p < 0.01) R5-R20 values.
Conclusions: Our results show that in asthmatic patients, small airway dysfunction, as assessed by IOS, is strictly
associated to BHR, expressed as excessive bronchoconstriction, but not as ease of airway narrowing