ELTGOL (Slow Expiration with the Opened Glottis in the Lateral posture) is an airway clearance technique performed in the lateral decubitus position. This technique focuses on optimizing ventilation of the infralateral lung (when the subject is lying in the lateral posture) to enhance local air-liquid interaction. Previous studies on ventilation differences between the infra- and supralateral lungs were conducted on healthy, young, male subjects, without the application of thoracic or abdominal pressure.

This study aimed to assess ventilation distribution in right lateral recumbency in patients with chronic obstructive pulmonary disease (COPD), as well as healthy individuals, and investigate the impact of thoracic and abdominal manual pressures during ELTGOL on ventilation distribution.

Electrical impedance tomography will be used to verify the effect of the lateral posture and associated breathing techniques in COPD and healthy individuals. The subjects will be placed in a standardised position before the measurements begin. The subjects will be placed in a right lateral recumbency position. The protocol comprises four manoeuvres, each interrupted by a short rest phase. Each subject will begin the experiment with the spontaneous ventilation manoeuvre in order to obtain the reference ventilation distribution. This will be followed by four other manoeuvres during which ventilation was measured: 1) using an spirometer to obtain a tidal volume of 1L, 2) performing the ELTGOL technique independently, 3) performing the ELTGOL technique assisted by manual pressures applied by a physiotherapist. 4) using a positive expiratory pressure (PEP) device.

Inclusion Criteria:

• Healthy subjects: No acute or chronic respiratory disease, normal lung function, non-smoker.
• Patients with COPD: forced expiratory volume at one second (FEV1) ≤ 80% predicted value, in stable state.

Exclusion Criteria:

• Healthy subjects: obesity (BMI > 35kg/m²); active or former smoker; severe scoliosis; cardiovascular or neuromuscular disease; active implant (cardiac pacemaker or an implantable cardioverter-defibrillator (ICD); thoracic skin lesion.
• Patients with COPD: obesity (BMI > 35kg/m²); severe scoliosis; severe cardiovascular disease; neuromuscular disease; active implant (cardiac pacemaker or an implantable cardioverter-defibrillator (ICD); thoracic skin lesion.