Based upon results of interim data analysis

Cystic Fibrosis (CF) is a genetic disorder of altered ion transport across cell membranes which is characterised by the production of thickened bodily secretions, affecting the function of organs such as the pancreas and the lungs. Within the lungs, thickened sputum is very difficult to clear, which can results in recurrent chest infections, which can lead to lung damage. therefore it is important to optimise the removal of sputum to try and prevent these complications. Traditionally, a variety of approaches are usually combined including inhaled medications to thin or hydrate secretions, and chest physiotherapy to mobilise secretions and improve sputum clearance.

There are many chest physiotherapy or airway clearance techniques (ACT) available including breathing methods such as the Active Cycle of Breathing Techniques (ACBT) or Autogenic Drainage (AD) and adjuncts such as Positive Expiratory Pressure (PEP), High Frequency Chest Oscillation (the "Vest"), or oscillatory devices such as the Flutter or Acapella. When people with CF have an infection or have severe disease often the effectiveness of ACTs can decrease due to fatigue, shortness of breath or having an overwhelming amount of sputum. At this time it is necessary to re-assess ACTs and the addition of positive pressure to airway clearance techniques has been shown to be helpful in decreasing fatigue during chest physiotherapy.

At present no research studies have reported an increase in sputum cleared with the addition of positive pressure, however it is thought that the ability to take a deeper breath when using positive pressure would help to improve sputum clearance. With clinical experience of the use of NIV with adult CF patients, the investigators aim to explore this objectively in this study.

Research Question:

Does the addition of non-invasive ventilation (Breas, I-Sleep 25) as supplementary positive pressure to normal airway clearance techniques improve sputum clearance in stable adult patients with cystic fibrosis?

Hypothesis

The inclusion of non-invasive ventilation in addition to a patient's normal airway clearance technique will lead to improvements in subjective ease of clearance and work of breathing during airway clearance and objectively increase sputum clearance, as well as being well tolerated in patients as an adjunct to airway clearance.

Cystic Fibrosis (CF) is a genetic disorder of altered ion transport across cell membranes which is characterised by the production of thickened bodily secretions, affecting the function of organs such as the pancreas and the lungs. Within the lungs, thickened mucus alters normal mucocillary clearance mechanisms resulting in airway obstruction, mucus plugging and recurrent infections. The cycle of recurrent infections and subsequent inflammation is thought to be the major mechanism towards damage to lung tissue and the occurrence of fibrosis, which decreases lung function, lowers tissue oxygenation and eventually leads to respiratory failure and death. Optimisation of the removal of airway secretions is therefore an integral part of the management of CF in order to try and prevent these complications. Traditionally, a variety of approaches are usually combined including mucolytic or hydrator therapy to make the secretions less viscous, and chest physiotherapy to mobilise secretions and improve airway clearance.

There are many chest physiotherapy or airway clearance techniques (ACT) available including breathing methods such as the Active Cycle of Breathing Techniques (ACBT) or Autogenic Drainage (AD) and adjuncts such as Positive Expiratory Pressure (PEP), High Frequency Chest Oscillation (the "Vest"), or oscillatory devices such as the Flutter or Acapella. Research has shown there to be no difference in effectiveness between techniques, as long as they are performed correctly and regularly, and therefore choice of ACT depends upon assessment of the patient by a trained physiotherapist and discussions with the individual. With advancing disease or infections, often the effectiveness of ACTs can decrease due to patient fatigue, shortness of breath or overwhelming amount of secretions. At this time it is necessary to re-assess ACTs, and the addition of positive pressure to airway clearance techniques has been shown to decrease patient fatigue and respiratory rates during clearance. One of these studies also demonstrated improvements in oxygenation and respiratory muscle strength after the use of positive pressure with ACT. While no studies have reported an increase in sputum expectorated with the addition of positive pressure, the ability to augment greater tidal volumes through positive pressure is thought to be a mechanism which could improve sputum clearance. Clinical experience at the Royal Brompton hospital has indicated that with alterations in pressure and flow rates from resting settings, sputum clearance appears to be easier and more effective; the investigators aim to explore this observation objectively in this study.

Research Question:

Does the addition of non-invasive ventilation (Breas, I-Sleep 25) as supplementary positive pressure to normal airway clearance techniques improve sputum clearance in stable adult patients with cystic fibrosis?

Hypothesis

The inclusion of non-invasive ventilation in addition to a patient's normal airway clearance technique will lead to improvements in subjective ease of clearance and work of breathing during airway clearance and objectively increase sputum clearance, as well as being well tolerated in patients as an adjunct to airway clearance.

Inclusion Criteria:

• Diagnosis of cystic fibrosis (confirmed by genotype or a sweat sodium concentration of >70mmol/l or sweat chloride of >60mmol/l)
• Sixteen years of age or over
• Patients admitted to the Royal Brompton Hospital with a pulmonary exacerbation of which is resolving. Patients will be considered for inclusion from day 7 of treatment to 3 days prior to discharge (as determined by a member of the cystic fibrosis medical team and have spirometric values within 20% of the mean of the last two stable recordings (at least 1 month apart)
• Patients with an established airway clearance regime that they have used for 3 months or more

Exclusion Criteria:

• Current moderate haemoptysis (greater than streaking in the sputum)
• Current pneumothorax or history of pneumothorax in the 3 months prior to consideration for the study
• Current dependency on positive pressure support with airway clearance via the IPPB (Intermittent Positive Pressure Breathing) machine or NIV
• Previous history of spontaneous rib fractures
• Pregnancy
• Inability to give consent for treatment or measurement
• Current participation in another study
• If the patient requires more than 2 airway clearance sessions a day