Improving Outcome Measures For Adult CF ACT Trials

Research Question: Does the use of a new assessment tool box (Electronic Impedance Tomography (EIT), Lung Clearance Index (LCI), Impulse Oscillation System (IOS)) give results that are more sensitive to change for the effect of an airway clearance technique (ACT) (the Active Cycle of Breathing Techniques (ACBT)) while having low variability and good repeatability in stable adult patients with cystic fibrosis (CF) than the traditional gold standard outcome measures of forced expiratory volume in one second (FEV1) and sputum wet weight?

Hypothesis: The use of a new outcome assessment tool box will allow more sensitive information about the effects of ACTs in stable adult patients with CF than the current gold standard measures.

This is a randomised controlled cross-over trial involving adult cystic fibrosis (CF) patients from the Royal Brompton Hospital, London. Participants will be their own controls. Each participant will attend the research facility for two visits. Prior to starting the study assessment session participants will be questioned to ensure they are in a stable state of their disease (characterised by symptoms and having had no treatment changes for 28 days prior to the visit). All participants will continue with the timing and prescribed dosing of all inhaled medications as directed prior to the study. Subjects will be their own controls. Subjects will be randomly assigned to the order that they perform the study sessions. Visit A will involve a period of rest for up to 60 minutes in-between assessments; Visit B will involve a session of airway clearance (ACT) utilising the Active Cycle of Breathing Techniques (ACBT) supervised by a specialist physiotherapist in adult CF. The ACT session will last for thirty minutes minimum, to 60 minutes maximum until a consensus is reached between participant and physiotherapist that the participant's chest is clear.

Subjects will perform the OM tests of impulse oscillation system (IOS), lung clearance index (LCI), and spirometry, then either rest (visit A) or perform a supervised ACBT session (visit B) using electronic impedance tomography (EIT) during the session. IOS, LCI and spirometry will be repeated immediately after the session. Sputum will be collected throughout the ACT or rest sessions and for 30 minutes after each of these sessions is completed. Questionnaires asking patient views on the OMs will be given for completion after the last OM test is completed on each study visit.

There are no planned follow up measurements for participants in this study design.

All usual medications will be permitted for this study. Attention will be paid to mucoactive drugs (Pulmozyme®, Mannitol®, Hypertonic saline) to ensure the same frequency and dosing of inhalations for both study visits.

Data will be analysed in 3 groups based upon disease severity. Analysis will be based upon differences in outcome measures and in-between study days.

Inclusion criteria

• Diagnosis of CF (confirmed by standard criteria)
• Sixteen years of age or over
• Patients in a stable state (characterised by no required therapy changes within 28 days of visit and patient symptoms)

Exclusion criteria

• Current infective exacerbation or reduction in lung function requiring therapeutic intervention
• Current moderate haemoptysis (greater than streaking in the sputum)
• Current dependency on positive pressure support with ACT
• Previous history of spontaneous rib fractures
• Pregnancy
• Inability to give consent for treatment or measurement
• Current participation in another interventional study
• Current dependency upon non-invasive ventilation
• Current dependency upon oxygen therapy