RT Journal Article
SR Electronic
T1 Investigating the interaction between bronchoconstriction and cough in asthma
JF European Respiratory Journal
JO Eur Respir J
FD European Respiratory Society
SP PA4192
DO 10.1183/13993003.congress-2016.PA4192
VO 48
IS suppl 60
A1 Imran Satia
A1 Huda Badri
A1 Mark Woodhead
A1 Paul O'Byrne
A1 Stephen Fowler
A1 Jaclyn Smith
YR 2016
UL http://erj.ersjournals.com/content/48/suppl_60/PA4192.abstract
AB Background: Cough is the archetypal airway reflex but it is unclear if there is an interaction between bronchoconstriction and cough reflex responses in asthma.Objective: To investigate the interaction between bronchoconstriction and cough in subjects with mild atopic asthma.Methods: For each subjects we determined the methacholine PC20 and the dose of capsaicin required to cause half the maximal response (ED50). Subjects underwent three interventions in a randomised single-blinded placebo controlled manner to assess the effects of:1;bronchoconstriction on evoked coughs,2;evoked coughs on bronchoconstriction,3;spontaneous resolution of FEV1 after bronchoconstriction on evoked coughs. Generalised estimating equations were used to model the interactions between bronchoconstriction and capsaicin evoked coughs.Results: Fourteen subjects were recruited (median age 23, 64% female). Compared to placebo, methacholine induced bronchoconstriction increased capsaicin evoked coughs (geometric mean 13.9 coughs (95% C.I. 10.9-17.8) vs. 8.4 coughs (6.6-10.7), 34% increase, p<0.001). The mean %FEV1 after inhaling methacholine immediately after capsaicin/placebo was unchanged (87.7% (84.2-91.1) vs. 86.3% (81.3-91.3) of baseline, p=0.49). Spontaneous resolution of FEV1 over 60 mins was associated with a reduction in capsaicin evoked coughs (p<0.001).Conclusion: Bronchoconstriction heightens cough responses to capsaicin in subjects with asthma.