The lungs make mucus to help defend against germs. Cystic fibrosis changes the mucus, making it thick and hard to clear. This mucus is where infections can occur. Infections cause inflammation, or swelling, of the lungs. Both infections and inflammation cause more mucus to be made. More mucus in the lungs can lead to more infections. This cycle of infection, inflammation and more mucus can hurt the lungs and keep them from working as well as they could.

The cycle can hurt lung function.

How CPT Works 

Brisk percussion of the chest wall helps to break up and dislodge mucus, so it can be more easily huffed or coughed out of the body.