Condition category
Date applied
Date assigned
Last edited
Retrospectively registered
Overall trial status
Recruitment status
No longer recruiting

Plain English Summary

Not provided at time of registration

Trial website

Contact information



Primary contact

Dr Ian Smith


Contact details

Respiratory support and sleep centre
Papworth Hospital NHS Trust
Papworth Everard
Papworth Everard
CB23 3RE
United Kingdom

Additional identifiers

EudraCT number number

Protocol/serial number


Study information

Scientific title

The impact of changing the pressure generating device in people with sleep apnoea using Continuous Positive Airway Pressure (CPAP) less than 4 hours per night: a randomised controlled crossover trial


Study hypothesis

Does changing to Bi−level positive airway pressure (Bi−level PAP) support increases usage in obstructive sleep apnoea (OSA) patients who have suboptimal compliance with fixed continuous positive airway pressure (CPAP) due to pressure intolerance?

The most effective treatment for symptomatic, moderate to severe OSA is with CPAP. To derive optimal benefit it is recommended that CPAP should be used for at least 4 hours per night. However, only 46-83 % of individuals use it for more than 4 hours every night. Different mechanical interventions (Auto positive airway pressure, Bi-level Positive airway pressure, and expiratory release positive airway pressure) have failed to show any significant improvement in compliance. Most of these studies have studied unselected subjects first initiating therapy. It is possible that subjects who after all simple measures to improve compliance have been addressed are still non-compliant may show a demonstrable improvement with a change of mode of pressure delivery. In this study we will evaluate the role of Bi-level PAP in OSA patients who remain poorly compliant with CPAP (despite appropriate interventions to improve local side effects and/or who complain of pressure related problems).

Ethics approval

Cambridgeshire 2 Research and Ethics Committee (REC), April 2009, ref: 09/H0308/68

Study design

Single-centre two-period two-arm randomised controlled crossover group trial

Primary study design


Secondary study design

Randomised cross over trial

Trial setting


Trial type


Patient information sheet

Not available in web format, please use contact details below to request a patient information sheet


Obstructive sleep apnoea


The study will have a two-period, two-treatment crossover randomised controlled trial design. Patients with average CPAP use less than 4 hours per night who meet the inclusion and none of the exclusion criteria will be randomised to either receive a Bi-level positive airway pressure (Bi-PAP) device first or to receive a brand of fixed CPAP machine different from the one they have used previous to entering the study. They will have a baseline measure of CPAP compliance, daytime sleepiness and quality of life. Both groups will receive a similar level of continuing clinical support by the CPAP practitioners and Respiratory Support and Sleep Centre (RSSC) nurses (24 hour telephone helpline, early clinic review and advice if there is any problem) as per the standard clinical care at our centre.
They will then be reviewed at 4 weeks with repeat measurements of compliance, sleepiness and quality of life.
For the second period, those that received CPAP in the first period will get Bi-level PAP and vice versa. They will go home with the advice to start using the new device after 2 weeks. Until that time they will stay on their initial CPAP. This will give them a washout period of two weeks. They will then be followed up for the study at 10 weeks with repeat measures of CPAP compliance, daytime sleepiness and quality of life indices to look for any measurable changes.
Patients will be selected from a cohort of CPAP users who are followed up at Papworth hospital.

Intervention type



Not Applicable

Drug names

Primary outcome measure

CPAP compliance (measured as average CPAP use in hours per night)

Secondary outcome measures

1. Improvement in generic quality of life index - Short form 36 (SF-36)
2. Improvement in sleep apnoea quality of life index (SAQLI)
3. Epworth sleepiness scale score (ESS)
4. Side effects
5. Comfort level
6. Patient preference for different device
7. Changes in objective measure of excessive daytime sleepiness (OSLER test)

Overall trial start date


Overall trial end date


Reason abandoned (if study stopped)


Participant inclusion criteria

1. Diagnosed OSA (AHI greater than 4 per hour)
2. On CPAP for at least 6 weeks with average use less than 4 hours per night
3. Intolerant of CPAP despite ensuring pressure minimised to least effective, mask fit and humidification reviewed as appropriate

Participant type


Age group




Target number of participants


Participant exclusion criteria

1. Refuse informed consent or unable to give consent.
2. AHI less than 5 per hour off CPAP.
3. Moderate to severe airflow obstruction (Forced Expiratory Volume in 1 second [FEV1] / Forced Vital Capacity Percentage [FVC%] less than 60%).
4. Central sleep apnoea (central events more than 50% of all the apnoeas / hypopnoeas).
5. Decompensated congestive heart failure on clinical examination.
6. Hypercapnia (PaCO2 >6.5 KPa).
7. Previous exposure to Bi−level positive airway pressure support.

Recruitment start date


Recruitment end date



Countries of recruitment

United Kingdom

Trial participating centre

Papworth Hospital NHS Trust
Papworth Everard
CB23 3RE
United Kingdom

Sponsor information


Papworth Hospital NHS Foundation Trust (UK)

Sponsor details

Dr Alistair Grant
Senior R and D manager
Papworth hospital NHS foundation trust
Papworth Everard
CB23 3RE
United Kingdom

Sponsor type

Hospital/treatment centre



Funder type

Hospital/treatment centre

Funder name

Papworth Hospital NHS Foundation Trust (UK) - (Local R& D ref: PO1349)

Alternative name(s)

Funding Body Type

Funding Body Subtype


Funder name

B and D electromedicals (UK) - limited funding

Alternative name(s)

Funding Body Type

Funding Body Subtype


Results and Publications

Publication and dissemination plan

Not provided at time of registration

Intention to publish date

Participant level data

Not provided at time of registration

Basic results (scientific)

Publication list

2015 results in:

Publication citations

Additional files

Editorial Notes

05/07/2016: Publication reference added.