Bronchiectasis are defined as irreversible dilatation of the bronchial tree. Patients with
bronchiectasis suffer of chronic cough and sputum production, and are predisposed to
recurrent airway infections. Many systemic diseases can cause bronchiectasis: cystic fibrosis
(CF), primary ciliary dyskinesia (PCD), primary immune deficiencies (PID) and idiopathic
bronchiectasis (IB) represent a significant proportion of patients with bronchiectasis
starting in early age.
Pulmonary function testing (PFT) and specifically forced expiratory volume in one second
(FEV1) is a common modality used to estimate lung disease progression and pulmonary
exacerbations in patients with bronchiectasis. Although patients with bronchiectasis tend to
have non reversible obstructive patterns on pulmonary function tests (PFTs), reversible
obstruction is not uncommon. While bronchodilator response (BDR) is a main characteristic of
asthma, the pathophysiology causing this phenomenon in bronchiectasis patients is less clear.
The improvement in FEV1 after inhalation of bronchodilators can be attributed to
bronchodilation or improved mucociliary clearance. It can be speculated that for some of the
bronchiectasis patients, hyper-reactive airways or asthma can contribute to the reversible
pattern. Despite the wide scale use of bronchodilators in bronchiectasis the evidence for its
efficacy is lacking. While some studies found that BDR is associated with more severe
disease, other studies did not find such associations.
According to ATS/ERS statement, the proper way to determine BDR, is by first recording three
attempts of spirometry, then delivering bronchodilators, and after a waiting time, obtaining
again at least three attempts of spirometry. The most resent ATS/ERS technical standard
suggests that change of >10% relative to the predicted value for FEV1 or forced vital
capacity (FVC) be considered a positive BDR.
While in most scenarios it is reasonable to assume that the change in FEV1 measured after the
waiting time can be attributed solely to the affect of bronchodilators, this is not
necessarily the case in bronchiectatic diseases. Theoretically, in bronchiectasis, the forced
expiration maneuver used in spirometry testing can potentially cause changes in lung
function, for example by inducing cough and mobilization of sputum. Evidence for this
assumption can be seen in that respiratory therapy in terms if positive expiratory pressure
(PEP) therapy can improve various parameters of lung function when tested again closely after
the therapy.
The goal of this study is to determine if bronchodilator response in bronchiectatic disease
might be influenced by other factors apart from the direct effect of bronchodilators.
Secondary objectives are to assess if BDR is associated with age, gender, specific
bronchiectatic disease, baseline FEV1, and other clinical factors such as sputum cultures,
IgE levels, eosinophil levels, computed tomography (CT) score, family history of asthma and
use of inhaled steroids.