The lungs provide protection against foreign particles entering the body by trapping unwanted particles in the mucous lining of the breathing tubes or airways.
Your secretions (mucous / sputum / phlegm) can be cleared from the lungs by coughing, breathing out (expiratory airflow) and the movement of tiny hairs called cilia. These tiny hairs line the breathing tubes (bronchi and bronchioles) and move like a wave to help propel the mucous and unwanted particles up to the mouth where they can be cleared by a cough.
The function of the tiny hairs (cilia) can be affected by smoke, oxygen therapy, alcohol and dehydration.
If you have a lung condition or a chest infection, the breathing tubes can become more swollen and reddened or (inflamed). As a result, the breathing tubes or airways can and may produce thicker and stickier mucous secretions (sputum or phlegm).
Repeated chest infections have been shown to contribute to deterioration in lung function. If sputum is not cleared from the lungs, it can cause ongoing inflammation, which can lead to further lung damage.
In some lung conditions, the ability to clear these secretions can be more difficult, resulting in:
- More coughing which increases your fatigue and can make you more breathless.
- Narrowing of the breathing tubes or airways, and tightness of the chest which can make breathing harder.
When to use airway clearance techniques will depend greatly on your individual needs. For example:
- Many people who have chronic lung conditions produce very little or no sputum. These people generally do not need to do any regular airway clearance techniques.
- Some people who have chronic lung conditions develop a moist cough when they have an infection. These people may need to do a few simple airway clearance techniques when this occurs.
A small number of people who have chronic lung conditions and who cough up sputum every day may need to use an airway clearance technique regularly.