TY - JOUR T1 - Inspiratory and expiratory airways resistance in relation to exercise-induced bronchoconstriction (EIB) and airways inflammation JF - European Respiratory Journal JO - Eur Respir J VL - 44 IS - Suppl 58 SP - P3967 AU - Henrik Johansson AU - Pasquale Pompilio AU - Margareta Emtner AU - Raffaele Dellaca AU - Andrei Malinovschi Y1 - 2014/09/01 UR - http://erj.ersjournals.com/content/44/Suppl_58/P3967.abstract N2 - Airways resistance measured by forced oscillation technique (FOT) is suggested to be a more sensitive marker of airway obstruction than spirometry. The significance of increased airways resistance after bronchial challenge in absence of significant FEV1-fall has not been studied. Furthermore, the choice of using inspiratory or expiratory resistance is debated.Exhaled NO (FeNO) at baseline and FEV1 and within-breath inspiratory and expiratory resistance at 5 Hz (R5insp and R5exp) were measured before and 10 minutes after a standardized exercise test in 116 children, aged 13-16 years, a subsample from a population-based study where subjects with current asthma were excluded. EIB was defined as a FEV1-fall≥10%.Higher baseline R5insp levels, but similar FEV1 levels (p=0.14) and R5exp (p=0.73), were found in subjects with EIB (n=34) vs without (n=82): 3.39 ± 0.12 vs 3.14 ± 0.06, p=0.04. Among subjects without EIB (n=82), large (>=25%) increase of R5insp (n=14) related to higher FeNO: 17.1 ppb (11.0, 26.6) vs 12.1 (10.7, 13.8), p=0.04. This was not found for large increase (≥25%) of R5exp (p=0.32). On the opposite, in subjects with EIB, large increase of R5exp (n=13) was associated with higher FeNO at baseline: 28.4 (17.2, 47.0) vs 12.4 (10.1, 15.4) (p<0.001), but this was not true for large increase of R5insp (p=0.24).In conclusion, inspiratory resistance appears to be a more sensitive marker of airways obstruction than FEV1 and exercise-induced changes in this parameter relate to subclinical airways inflammation in subjects without EIB. Exercise-induced changes in expiratory resistance were associated with airways inflammation in subjects with EIB. ER -