<unk>  is when devices are used in airway clearance therapy to clear excess mucus from lung airways (bronchi and bronchioles). It is principally used in the treatment of cystic fibrosis, but is gaining use in the treatment of other diseases, such as bronchiectasis, COPD, cerebral palsy and muscular dystrophy, in which excessive mucus can block airways due to excessive production or impaired clearance. This "passive system" is not dependent on the effort of the patient. It uses a compressor to inflate and deflate the vest rhythmically at timed intervals and thus imposes high frequency<unk> s (HFCWO) that are transferred to the lungs. These<unk> s thin thixotropic airway mucus, facilitating its removal by coughing. Delivery of air to the vest can be controlled manually.
Chest wall oscillation
Cough reflex
Airway resistance
Biot's respiration
Breathing circuit
Diaphragmatic excursion
Mouth breathing
Liquid breathing