High frequency chest wall oscillation (HFCWO) has been shown to increase tracheal mucus clearance compared with a control group. These observations led to the development of The Vest® which is a non-stretchable jacket connected to an air-pulse generator and worn by the patient over the chest wall. The generator rapidly inflates and deflates The Vest®, which gently compresses and releases the chest wall between 5 and 20 times per second. This generates mini-coughs that are said to dislodge mucus from the bronchial walls and to facilitate its movement up the airways. The Vest® has been shown to reduce the viscosity of mucus and this should further enhance mucus clearance.

People with cystic fibrosis (CF), admitted to hospital with an acute infective pulmonary exacerbation, should increase the frequency and duration of their airway clearance sessions owing to the increase in quantity and viscosity of purulent bronchial secretions.In the United Kingdom, and in many other countries, the availability of physiotherapists to assist with the recommended number of daily treatments is insufficient to meet patient need. If the use of high frequency chest wall oscillation, in addition to 'usual' self airway clearance techniques, in the early morning and evening was to facilitate recovery from an exacerbation, this would indicate an important place for high frequency chest wall oscillation in the management of people with cystic fibrosis.

Hypothesis:

The addition of high frequency chest wall oscillation to twice daily supervised physiotherapy is as effective as the addition of self treatment in facilitating recovery from an acute infective pulmonary exacerbation, as measured by improvement in lung function, specifically forced expiratory volume in one second (FEV1).

Inclusion Criteria:

• Diagnosis of cystic fibrosis
• Hospitalised patients admitted with a pulmonary infection
• Forced expiratory volume in one second (FEV1)of 15% predicted or over
• 16 years of age or over

Exclusion Criteria:

• Current severe haemoptysis
• Rib fractures or history of spontaneous rib fractures
• pregnancy
• Lung abscess
• End stage disease
• Requiring more than two assisted treatment sessions per day
• Requiring treatment with positive pressure
• Inability to give consent