Introduction

Airway clearance techniques (ACTs) represent a panel of various techniques performed by the external application of forces to

clear bronchial secretions from the lungs1. ACTs facilitate sputum transport via manipulation of lung volumes, gas flow,

pulmonary pressures and compressive forces. A combination of these factors exerts shearing forces onto sputum at the

air-liquid interface, and the resulting energy transfer shifts secretions towards the mouth. This mechanism is well known as

two-phase gas-liquid flow and is considered essential for lung clearance in patients with mucociliary dysfunction to improve

ventilation².

Several types of ACTs are used in clinical practice: conventional therapy (postural drainage, percussion, vibration), breathing

exercises (ACBT, autogenic drainage), Positive Expiratory Pressure (PEP devices) and mechanical devices applied externally to the

chest wall (HFCWO).

Cystic fibrosis (CF) is a disorder that interrupts the lungs normal mucus secretion, causing excessive production of viscid mucus,

which leads to mucus plugging, recurrent infections, and inflammation, followed by airway damage and lung function

deterioration.

ACTs have the short-term effect of increasing mucus transport in CF3. Available clinical evidences showed that no ACTs

demonstrated to be superior to others and that the prescription of ACTs should be individualized based on patient preference5,6,7

although some devices seem to reduce rate of long term respiratory exacerbation8.

Chronic obstructive pulmonary disease (COPD) is an umbrella term used to described progressive lung diseases including

emphysema, chronic bronchitis, and refractory asthma as Asthma-COPD Overlap Syndrome (ACOS). COPD patients often

experience dyspnea, cough, sputum and chest tightness which may worsen during acute exacerbation of COPD (AECOPD).

Patients with bronchiectasis have more severe symptoms, purulent sputum expectoration and acute exacerbation, and may be

good responders to ACTs9.

ACTs are safe and enhance mucus clearance in COPD1, 4. Performing ACTs reduced during an AECOPD the likelihood of needing

mechanical ventilation, as well as the length of time for which it was required4. There are a few evidences to suggest some

benefits on future exacerbation or health-related quality of life10, 11. Performing ACTs during stable COPD do not affect

exacerbation or hospitalizations but may improve health-related quality of life4.

Simeox (Physio-Assist, France) technology is an innovative ACT which mobilizes mucus in the distal tracts to change its

rheology and transport it to the proximal tract for expectoration. The device generates a succession of very short air depressions

of constant volume at a frequency similar to that of the vibratory cilia of the bronchial epithelium by disseminating a vibratory

pneumatic signal in the bronchial tree during relaxed exhalation. This signal allows a direct intrapulmonary action on the dynamic

viscosity and mobilization of the bronchial mucus.

The viscosity decreases sharply by the shear thinning property and thixotropy of mucus. Relaxed exhalation is ensured by the

device with an aid for preventing airway collapse and increasing the expiratory time.

The main target diseases of Simeox are CF, COPD, bronchiectasis and primary ciliary dyskinesia.

Simeox can be used as part of a bronchial drainage session after the patient has been trained by a physiotherapist. The touch

screen interface allows biofeedback that facilitates real-time visualization of the progress of patient treatment..

This clinical documentation brings together the experience with the Simeox technology of several recognized national centers of

medical expertise and research from different EU countries (France, Poland, Czech Republic, Romania, Slovakia and Russian

federation) in the management of patients with various obstructive lung diseases (Cystic fibrosis, COPD, non-CF bronchiectasis,

pulmonary fibrosis, ILD) suffering from pulmonary congestion and requiring airway clearance.

Each center performed a pilot prospective study with the aim of assessing short-term benefits and safety of Simeox technology

compared to conventional physiotherapy in patients hospitalized for either acute pulmonary exacerbation of chronic lung

disease or routine medical checkup. Patients with acute exacerbation were treated for chest congestion with Simeox for 5-7 days

(1 or 2 sessions per day) during hospitalization while receiving optimal drug therapy. Pulmonary function tests, symptoms, mucus

clearance, SpO2, usability, quality of life and adverse events were evaluated during the study.

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