A Randomised Feasibility Study of CPAP in Large Airway Collapse

Large airway collapse (LAC) is an increasingly recognised condition characterised by either bowing of the posterior membrane/trachealis muscle into the trachea or main bronchi (also known as excessive dynamic airway collapse, EDAC) or weakening of the tracheal cartilage (also known as tracheobronchomalacia, TBM).(1-3) LAC often co-exists with other chronic airway conditions, such as asthma or chronic obstructive pulmonary disease (COPD) and is frequently misdiagnosed or overlooked as symptoms, such as shortness of breath, cough and wheeze overlap with other respiratory disease.(1) There is no standardised treatment pathway for patients diagnosed with LAC and current treatment options are limited to physiotherapy and/or hypertonic saline.(3) Exacerbations of LAC, defined as an acute worsening of respiratory symptoms, typically reduce health-related quality of life and increase healthcare utilisation.(4) Small studies and case series have suggested continuous positive airway pressure (CPAP) as a potential treatment for LAC to reduce exacerbations and improve quality of life.(5,6) It is hypothesised CPAP may work as a pneumatic splint helping to prevent dynamic collapse of the large airways. This may increase lung volumes due to increase in flow at functional residual capacity (FRC) and support higher elastic recoil and increased expiratory flow. Additionally, splinting of the large airways may cause stiffening of the large airways, resulting in less resistance and turbulence during expiration and may support sputum expectoration.(3) There is a need for high quality randomised controlled trial (RCT) evidence to inform clinical recommendations in the United Kingdom (UK), as well as globally. Prior to this there is a need for further work exploring the feasibility of performing a large RCT and understanding the acceptability of CPAP as a future treatment for LAC.

Aim To conduct a randomised feasibility study that will provide data to confirm if a larger randomised trial of CPAP in patients diagnosed with LAC is viable

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Key information

Conditions

Large Airway Collapse Asthma Bronchial Diseases Hypersensitivity Hypersensitivity, Immediate Immune System Diseases Lung Diseases Lung Diseases, Obstructive Respiratory Hypersensitivity Respiratory Tract Diseases

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

Adult (≥18 years) at visit 1
Able to provide informed consent
Prior confirmation of LAC (diagnosed either radiographically or with bronchoscopy)
Respiratory co-morbidities optimised
≥1 course of antibiotics and/or prednisolone for an exacerbation of chronic airway disease in the preceding 12 months before visit 1.

Exclusion criteria

Contraindication to CPAP as per British Thoracic Society (BTS) guidelines
Already using domiciliary CPAP (including privately purchased)
Known obstructive sleep apnoea syndrome (OSAS) eligible for CPAP
Suspected OSAS that is awaiting further investigation
Pregnant or planning a pregnancy in the next 12 months

Treatment and study plan

CPAP

Device

Nocturnal CPAP

Primary outcomes

Patient acceptability

Time frame: From Enrolment until 1 year
- All participants will be asked to complete a questionnaire, which will give us information about their diagnosis pathway, current health and wellbeing related to LAC and other information about treatment options.
- Participation in an audio-recorded semi-structured interview will be offered to participants in both arms, to facilitate the collection of more detailed insights surrounding LAC as a condition, diagnosis pathway, treatments (including CPAP). Interview topic guides will be co-produced with the patient and public involvement (PPI) lead. Interviews will be scheduled at the patient's convenience on or after visit 3 (6 months) and will be conducted face-to-face, virtually or by telephone. We will aim to interview up to 10 participants in each arm, or until data saturation is reached. Interviews will be recorded using industry standard recording device/Dictaphone, transcribed, and data analysed under the guidance of the qualitative lead.
Recruitment and Retention

Time frame: At 18 months post enrolment

The site will be asked to keep a screening log of all patients identified, approached and given an information leaflet.

The number of participants enrolled (defined as a participant providing written informed consent) and the proportion randomised will be reported. Reasons for screen failure and withdrawal will be collected and summarised in the CRF.

Recruitment and retention will be periodically assessed in line with agreed targets with the funder.

Secondary outcomes

Health Related Quality of Life Assessment

Time frame: At enrolment and 18 months

The SGRQ is a 50-item questionnaire used to assess the health and wellbeing of patients with chronic respiratory disease. The questionnaire is composed of 2 parts: part 1 measures symptom burden and part 2 ascertains the impact of their disease on a range of activities that encompass social function, psychological disturbance and physical ability. Scores range from 0 to 100 with a higher score indicating more limitations.

The SGRQ will be administered at all on-site visits. A total score will be collected to analyse participant trajectories over the duration of the study and conduct comparative analyses between study arms, considering minimally important clinical differences.
Healthcare Resource Utilisation

Time frame: At 18 months post enrolment
- Primary care (General Practitioner (GP), nurse, other)
- Secondary care (respiratory, non-respiratory, consultant, nurse, or other), community service (pharmacist, other)
- Emergency department attendance (respiratory or non-respiratory)
- Inpatient admission (elective, emergency), admission duration

Study contacts

Contact information is provided by the study sponsor or research team.

Rachel Burton Dr Burton, MD

CONTACT

[email protected]

+441517053100

Rebecca Nightingale Dr Nightingale, PhD

CONTACT

[email protected]

+441517053100

Sponsors and collaborators

Lead sponsor

Liverpool School of Tropical Medicine

Other

Collaborators

Royal Liverpool University Hospital

Registry information

Acronym: RE-LACS

Important dates

Study start: 2026
Primary completion: 2028
Study completion: 2028
First posted: Apr 1, 2026
Registry last updated: Apr 1, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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