Introduction Bronchiectasis is a chronic disorder characterised by permanent and irreversible abnormal dilation of the bronchi and bronchioles, primarily caused by repeated cycles of pulmonary infections and inflammation, which lead to reduced mucociliary clearance and to the excessive production of sputum. Patients with non-cystic fibrosis bronchiectasis may be predisposed to hypoxemia during sleep, or to symptoms that may lead to arousals and thereby reduce the quality of life, because of the irreversible dilation of the bronchi and the presence of secretions and airflow obstruction.

Methods and analysis For this cross-sectional observational study, patients with a clinical diagnosis of non-cystic fibrosis bronchiectasis will be recruited from the Bronchiectasis Clinic of the Pneumology Department of the Santa Casa de Misericordia Hospital and the Federal University of São Paulo (São Paulo, Brazil). Patients of either sex will be included if high-resolution CT of the thorax and classic sweat test confirms they have non-cystic fibrosis bronchiectasis, are between 18 and 80 years old, use long-acting bronchodilators, are clinically stable for a least 1 month, agree to participate in the study and they sign a statement of informed consent. The first part of the study will involve a clinical evaluation, maximal respiratory pressures, spirometry and the Saint George's Respiratory Questionnaire. The Sleep Laboratory of the Master's and Doctoral Postgraduate Program in Rehabilitation Sciences of the Nove de Julho University (São Paulo, Brazil) will perform the polysomnographic studies, Berlin Questionnaire, Epworth Sleepiness Scale, waist and neck circumferences, modified Mallampati classification and tonsil index.

Ethics and dissemination This protocol has been approved by the Human Research Ethics Committees of Santa Casa de Misericordia Hospital (process number 178/2012) and Human Research Ethics Committee of Nove de Julho University (process number 370474/2010). All participants will sign a statement of informed consent. The study findings will be published in peer-reviewed journals and presented at conferences.