Physiotherapy is a key treatment for patients with bronchiectasis. An evaluation of the parameters indicative of respiratory health in patients treated with two different respiratory physiotherapy techniques (conventional versus Simeox®) would be very useful in choosing physiotherapy treatments for bronchiectasis patients. A systematic review of the literature shows that there are no published studies evaluating the effectiveness of respiratory physiotherapy by analyzing the variation in resistance measured using the forced oscillation technique (FOT) in patients with bronchiectasis. The results of this study would add to those that have examined different physiotherapy techniques and could therefore contribute to the choice of the most appropriate technique for this category of patients.

The trial is being conducted to answer the question: "How do respiratory parameters vary during treatment with two different respiratory physiotherapy techniques: conventional respiratory physiotherapy or that performed using the Simeox device?" Secondary objectives include the measurement of various functional parameters, such as vital signs (heart rate, respiratory rate, blood oxygenation, blood pressure values) and spirometry values (FEV1, FVC, TLC). The onset of adverse events, the degree of patient tolerance and relief, and respiratory health will also be assessed through the administration of various questionnaires commonly used in clinical practice. Additionally, changes in the quantity of sputum produced will be measured.

Single-center, prospective, open-label, 2x2 randomized crossover study. It is planned to consecutively enroll all outpatient patients who attend the bronchiectasis clinic of the Pneumology and Respiratory Intensive Care Unit of the IRCCS, University Hospital of Bologna, Policlinico S. Orsola. The study has a 2x2 crossover design for superiority. Each enrolled patient will undergo two treatment periods, each lasting 4 weeks. Patients randomized to Group A will undergo the first treatment with conventional respiratory physiotherapy techniques (usually with Acapella, PEEP bottle, PEP mask, according to current clinical-assistance practice at our clinic), while patients randomized to Group B will start treatment with the Simeox® device.

At the end of the first 4 weeks, the treatment will be interrupted, and a 1-week wash-out period will be observed. Based on what is commonly observed in clinical practice, it is believed that 1 week of wash-out is adequate time for mucus to re-accumulate in the airways and restore the baseline conditions necessary for the crossover, while also avoiding the risk of adverse events due to mucus accumulation. At the end of the wash-out week, the second phase of the study will begin, also lasting 4 weeks, with a treatment switch: Group A patients will use the Simeox® device, and Group B patients will undergo conventional respiratory physiotherapy.

Randomization will be conducted with a 1:1 ratio without stratification by the statisticians of the Research and Innovation Unit of the IRCCS AOUBO using statistical software. The randomization list will be entered into the study's eCRF, created with REDCap, and will be consulted by the investigators at each new enrollment. Treatment arm assignment will be performed at V1.

If the enrolled patients are already undergoing respiratory physiotherapy, they will be subjected to a 1-week wash-out period before starting the study, during which respiratory physiotherapy will be suspended. The Investigators will not include patients with cystic fibrosis (CF) in the study, as the production of bronchial secretions in this group of patients is substantial. In patients with bronchiectasis not due to CF, however, secretion production is generally much more modest, and, as done in other studies, a short wash-out period does not significantly increase risks for these patients. For greater caution, the study will only be proposed to patients in a stable phase (absence of ongoing exacerbations) and with sputum production < 200 mL/day (comparable to 1 plastic cup). These are the criteria by which, in clinical judgment, "non-strongly secretive" patients are identified. During the wash-out period, patients will be invited to contact us immediately if sputum production exceeds 200 mL/day, in which case the investigators will exclude the patient from the study and arrange a short-term visit.

Inclusion Criteria:

• Patients with a diagnosis of bronchiectasis not due to cystic fibrosis who are not hospitalized.
• Age ≥ 18 years.
• Evidence of bronchiectasis in at least one lung lobe from a chest CT scan performed within the 10 years prior to enrollment.
• Absence of exacerbations in the 28 days preceding enrollment.
• Sputum producers with volumes less than or equal to 200 mL/day.
• Under treatment with optimized standard therapy for bronchiectasis that has been stable for at least one year, with no changes in the 28 days prior to enrollment.
• Eligible for and/or already undergoing respiratory physiotherapy.
• Signed informed consent.

Exclusion Criteria:

• Diagnosis of COPD or bronchial asthma interpreted as primary and predominant diseases compared to bronchiectasis.
• Presence of tracheostomy.
• History of significant hemoptysis (≥300 mL of blood) or requiring embolization or blood transfusions in the 4 weeks preceding enrollment.
• Hemodynamic instability (mean arterial pressure < 65 mmHg, heart rate > 110 bpm).
• Undrained pneumothorax (evident on chest X-ray, deemed not worthy of pleural drainage according to standard clinical-assistance pathways and thus subjected to follow-up).
• Women who are pregnant or breastfeeding.