Symptomatic Treatment of Excessive Dynamic Airway Collapse Using Daytime Portable Continuous Positive Airway Pressure

The aim of this study is to assess the benefit of a portable ventilator generating positive end-expiratory pressure on exercise tolerance in patients with Excessive dynamic airway collapse (EDAC) and tracheobronchomalacia (TBM).

Excessive dynamic airway collapse (EDAC) and tracheobronchomalacia (TBM) occur due to abnormal weakening of the walls of the central airways leading to central airway collapse on expiration. This collapse is responsible for breathlessness, cough or syncope. In adults, this weakening can be idiopathic (Mounier-Khun syndrome), secondary to respiratory diseases such as chronic obstructive pulmonary disease (COPD), secondary to systemic diseases such as relapsing polychondritis (RP) or secondary to invasive ventilation or trauma. The incidence of EDAC and TBM varies from 12% in all patients undergoing bronchoscopy to 44% in patients with chronic bronchitis undergoing bronchoscopy. Gold standard for the diagnosis of EDAC and TBM is bronchoscopy which identifies and quantifies the narrowing of the airway. Non-invasive technique such as inspiratory and expiratory chest computed-tomography (CT) can also be used to diagnose EDAC / TBM.

Currently, in addition to management of the underlying disease, treatment options for EDAC / TBM are limited. Surgical tracheoplasty can be offered but can be associated with severe post-operative complications. Airway stenting can also be offered but, even if this treatment improved quality of life, it fails to improve exercise capacity. Airway stenting is also associated with infectious complications as well as stent migrations. Other endoscopic treatment such as Yttrium Aluminium Perovskite laser can be offered with good results but have not yet been validated in a randomised trial. Nocturnal non-invasive ventilation (NIV) can also be used, especially in patients with associated obstructive sleep apnoeas but again there is not randomised clinical trial evidence that validates this approach in adults. Expiratory Positive Airway Pressure (EPAP) provides a pneumatic stenting that prevents the expiratory collapse of the airway. But, by giving the NIV during the night, patients are left without any support during the day whilst their respiratory demand is higher and when they are more symptomatic. Currently, NIV is only given at night or at rest because current non-invasive ventilators are not suitable for ambulatory use as they are heavy. Recently, a new portable ventilator with built-in battery has been issued (Z1®, Breas®). This ventilator is light (500g) portable and has a working duration of 8 hours. Therefore, it can be easily carried and used while walking. By providing a nasal pillow interface (Nasal swift®, Resmed®) to patients, it will allow them to walk safely with the device on.

Eligibility Criteria:
Inclusion Criteria:

* Patient with diagnosed EDAC or TBM on inspiratory/expiratory CT or bronchoscopy
* Patient with exertional dyspnea

Exclusion Criteria:

* Pregnancy
* Significant physical or psychiatric comorbidity that would prevent compliance with trial protocol
* Inability to perform 6-MWT
* Current intra-tracheal stent
* Previous surgery for EDAC or TBM
* Uncontrolled underlying disease:

  * Initiation of home mechanical ventilation in last 3 months
  * Uncontrolled joint pain