Dysfunctional Breathing in Post COVID-19 Condition.

Will be assesed in a supine position, using the RMMI. First, during 30 seconds of tidal volume breathing. Second, during 60 seconds of performing maximal breathing manoeuvres interspaced by tidal volume breathing and then during 60 seconds after performing activity that triggers dyspnea. The RMMI records bilateral changes in the anterior posterior diameter, including both upper and lower thoracic and abdominal movements.

Health-related Quality of Life is measured with EuroQualityOf Life 5 dimensions questionnaire (EQ-5D-5L), which is an instrument that evaluates the generic quality of life. EQ-5D includes a descriptive system, which comprises 5 dimensions of health: mobility, selfcare, usual activities, pain/discomfort, and anxiety/depression. A descriptive index-score between 0-1, higher score indicates higher HRQoL. EQ-5D also includes a visual analog scale (VAS), which records self-rated health status on a graduated (0-100) scale, with higher scores for higher HRQoL

Maximal Inspiratory muscle strength (MIP) will be measured with Micro RPM in cmH2O

Maximal expiratory muscle strength (MEP) will be measured with Micro-RPM in cm H20

Chest mobility will be measured with a tape measure at the xiphoid process and the 4th rib

Six-minute walk to measure endurance (in meters)

Lung function test with forced vital capacity (FVC), forced expiratory flow in one second (FEV1), diffusion capacity (DLCO)

End tidal CO2 measured during exercise

Measured with Frändin/Grimby activity scale, which is a self-assessment scale about current levels of physical activity, ranging from 1 to 6. The higher the score, the higher level of physical activity.

Dysfunctional breathing will be assessed with the Nijmegen questionnaire. The questionnaire consists of 16 items asking about the symptoms related to dysfunctional breathing.

Participants will grade how often they suffered from each item on a five-point Likert scale, ranging from 0 to 4, in which 0 is never ,1 is rarely, 2 is sometimes , 3 is often , and 4 is very often. Total score ranging from 0 to 64. A score of 23 and over indicates dysfunctional breathing.

COPD Assessment Test (CAT), questionnaire of symptoms related to breathing and now commonly used for this group of patients. COPD Total score ranging from 0 to 40, where a higher number indicates more symptoms

Dyspnea (mMRC, Modified Medical Research Council 0-4), Dyspnea Scale and BORG CR10).

Modified Medical Research Council (mMRC), which is a self-rating tool to measure the degree of disability that breathlessness postures on daily physical activities on a scale from 0 to 4. 0, no breathlessness except on strenuous exercise; 1, shortness of breath when hurrying on the level or walking up a hill; 2, walks slower than people of same age on the level because of breathlessness; 3, stops for breath when walking at their own pace on the level; and 4, Breathless when washing or getting dressed.

Borg CR-10 ranging between 0-10. The higher the score, the higher the dyspnea.

Depression will be assessed with the Patient Health Questionnaire (PHQ-9). PHQ-9 which contains 9 items. Total score ranges from 0 to 27. Higher score indicate more severe depression symptoms

Anxiety will be assessed with the Generalized Anxiety Disorder 7-item scale (GAD-7) which is a self assessment tool. Total score ranging from 0-21. Higher score indicates higher anxiety.

The Brompton BPAT (BREATHING PATTERN ASSESSMENT TOOL) will be used. Assessment components include (i) evaluation of chest/abdominal wall movement, noise of (ii) inspiratory and (iii) expiratory flow, (iv) channel of inspiration and expiration, (v) signs of air hunger (yawning, sighing and deeper breaths), (vi) RR and (vii) rhythm. Each component is given a score from 0 to 2, based on features consistent with expected normal (0) versus that present in severe dysfunctional breathing (2), giving a total score of between 0 and 14. The BPAT is completed with a patient positioned, as per the standard assessment of resting breathing pattern (i.e. sat comfortably in a supported seat for at least 5 min) and takes approximately 1 min to collate.

The thickness of the diaphragm will be measured using ultrasound at end-inspiration and end-expiration and is presented in cm.

The movement of the diaphragm at rest, at deep breathing and at sniff manuver will be measured using ultrasound and presented in cm.

The velocity of the diaphragm movment will be measured with ultra sound and presented as cm/s.

The thickening fraction of the diaphragm will be measured using ultrasound and is calculated using a formula, thickening fraction=(end-inspiration - end-expration)/ end-expiraton ×100%. Measurements are performed 3 times and the average value is calculated and presented.