Obstructive Sleep ApneaExpFLOSANCT02612038
Nasal Expiratory Resistance in Patients With Sleep Apnea and Expiratory Flow Limitation
A study testing Expiratory resistance in people with Obstructive Sleep Apnea, run by Brigham and Women's Hospital.
Trial summary
Obstructive sleep apnea (OSA) is inherently site-specific. In a physiological controlled intervention study, the investigators seek to determine whether applying expiratory resistance can acutely improve ventilation and sleep in patients with expiratory flow limitation (EFL). Read more about this study
- Who is it for?
- Ages 21 to 70 years
- Conditions the study is for
- Obstructive Sleep Apnea
- What is being tested?
- Expiratory resistance
- Type of treatment
- Medical device
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 0 participants
- Where
- No sites listed yet
- Study dates
- 1 May 2016to 1 May 2017
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 21 to 70 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Presence of obstructive sleep apnea (AHI>10/hr)
Who cannot join
- Serious co-morbidities including lung disease, heart disease, renal disease
- Medications affecting respiration or sleep
- Expiratory flow limitation (EFL) subgroup inclusion criteria: presence of clear EFL on polysomnographic study (reduced flow and increased pharyngeal pressure during expiration as a predominant cause of airflow obstruction).
- non-EFL subgroup inclusion criteria: complete absence of EFL on polysomnographic study
About this study
Obstructive sleep apnea (OSA) is inherently site-specific. In a physiological controlled intervention study, the investigators seek to determine whether applying expiratory resistance can acutely improve ventilation and sleep in patients with expiratory flow limitation (EFL).
Read the detailed description
Collapse of the upper airway can occur at different sites of the pharynx. One common and recognizable form of pharyngeal collapse is prolapse of the soft palate (velopharynx) on expiration, a phenomenon referred to as expiratory flow limitation (EFL). In principle, application of nasal positive expiratory pressure should reverse expiratory narrowing, increase ventilation, and prevent the subsequent progressive loss of airflow that leads to arousal from sleep, thereby improving OSA. One means to achieve this expiratory pressure is with the use of an added nasal expiratory resistance.
Accordingly, during a single night protocol, the investigators will examine the effects of increasing nasal expiratory resistance during sleep. During obstructed breathing, patients will be switched acutely, in random order, from normal conditions to an added expiratory resistance (30-80 cmH2O/L.s) or a sham resistance, for short (1 min) and prolonged periods (1 hour), repeatedly overnight.
Patients participating in the study will be divided into two groups, those exhibiting EFL versus those without EFL (i.e. with inspiratory flow limitation).
The main outcomes of the short physiologic interventions are:
- Increase in ventilation, and
- Increased time to a respiratory-related arousal from sleep, relative to sham conditions.
The main outcome of the prolonged interventions is:
--Reduced frequency of respiratory events (AHI; 3% desaturation or arousal) relative to sham conditions.
The central objective of the study is to test whether there is a greater improvement in the above outcomes in those with EFL versus those without EFL.
This data will allow us to test whether expiratory resistance is of potential therapeutic benefit specifically in patients with EFL rather than those without EFL.
- Conditions
- Obstructive Sleep Apnea
- Being tested
- Expiratory resistance, Sham expiratory resistance
- Keywords
- Obstructive sleep apnea, Expiratory flow limitation
- Medical subject headings
- Sleep Apnea, Obstructive
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Expiratory resistanceDevice
Also called Expiratory positive pressure
Generic expiratory resistance will be added to the patient's respiratory circuit
Sham expiratory resistanceDevice
Sham expiratory resistance will be added to the patient's respiratory circuit
| Study group | Role | What they receive |
|---|---|---|
| Expiratory resistance | Experimental | Generic expiratory resistance will be added to the patient's respiratory circuit Receives: Device: Expiratory resistance |
| Sham expiratory resistance | Sham comparator | Sham resistance will be added to the patient's respiratory circuit Receives: Device: Sham expiratory resistance |
What is being measured
The primary outcome is the main question the study is designed to answer.
Increase in ventilation (L/min) from baseline
Measured: Acutely (1 min)
Secondary outcomes (2)
Increase in time to arousal from sleep
Measured: Acutely (1 min)
Reduction in frequency of respiratory events (apnea-hypopnea index, 3% desat/arousal; NREM supine)
Measured: Acutely (1 hour)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted23 Nov 2015 (estimated)
- Study start1 May 2016
- Primary completion1 May 2017
- Study completion1 May 2017
Why it stopped: No funding was available for the study
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Obstructive Sleep ApneaStudies of the same condition, open and under way.
- More trials run by Brigham and Women's HospitalThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Single blind
- Who is masked
- Participant
- Enrolment
- 0 participants (actual)
Sponsor and investigators
- Lead sponsor
- Brigham and Women's Hospital
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, David Andrew Wellman, Brigham and Women's Hospital
- Investigators
- Andrew Wellman, PhD MD, Principal investigator, Brigham and Women's Hospital
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT02612038
- Sponsor's protocol ID
- 2012P000957E
- Acronym
- ExpFLOSA
- Status last verified
- Sep 2026
- First submitted
- 19 Nov 2015
- Last updated
- 8 Sep 2026
- Results posted
- No
- Data monitoring committee
- No
Study at a glance
From the registry record, last updated by the sponsor on 8 Sep 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Nasal Expiratory Resistance in Patients With Sleep Apnea and Expiratory Flow Limitation
- ClinicalTrials.gov ID
- NCT02612038
- Acronym / sponsor ID
- ExpFLOSA / 2012P000957E
- Conditions
- Obstructive Sleep Apnea
- Keywords
- Obstructive sleep apnea, Expiratory flow limitation
- Study type
- Interventional
- Recruitment status
- WithdrawnReason stopped: No funding was available for the study
- Enrolment
- 0 participants (actual)
- Lead sponsor
- Brigham and Women's HospitalUniversity, hospital or other
- Study start
- 1 May 2016 (actual)
- Primary completion
- 1 May 2017 (actual)
- Study completion
- 1 May 2017 (actual)
- First posted
- 23 Nov 2015 (estimated)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Obstructive sleep apnea (OSA) is inherently site-specific. In a physiological controlled intervention study, the investigators seek to determine whether applying expiratory resistance can acutely improve ventilation and sleep in patients with expiratory flow limitation (EFL).
Detailed description
Collapse of the upper airway can occur at different sites of the pharynx. One common and recognizable form of pharyngeal collapse is prolapse of the soft palate (velopharynx) on expiration, a phenomenon referred to as expiratory flow limitation (EFL). In principle, application of nasal positive expiratory pressure should reverse expiratory narrowing, increase ventilation, and prevent the subsequent progressive loss of airflow that leads to arousal from sleep, thereby improving OSA. One means to achieve this expiratory pressure is with the use of an added nasal expiratory resistance.
Accordingly, during a single night protocol, the investigators will examine the effects of increasing nasal expiratory resistance during sleep. During obstructed breathing, patients will be switched acutely, in random order, from normal conditions to an added expiratory resistance (30-80 cmH2O/L.s) or a sham resistance, for short (1 min) and prolonged periods (1 hour), repeatedly overnight.
Patients participating in the study will be divided into two groups, those exhibiting EFL versus those without EFL (i.e. with inspiratory flow limitation).
The main outcomes of the short physiologic interventions are:
- Increase in ventilation, and
- Increased time to a respiratory-related arousal from sleep, relative to sham conditions.
The main outcome of the prolonged interventions is:
--Reduced frequency of respiratory events (AHI; 3% desaturation or arousal) relative to sham conditions.
The central objective of the study is to test whether there is a greater improvement in the above outcomes in those with EFL versus those without EFL.
This data will allow us to test whether expiratory resistance is of potential therapeutic benefit specifically in patients with EFL rather than those without EFL.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Single blind (participant)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Expiratory resistance | Experimental | Device: Expiratory resistanceGeneric expiratory resistance will be added to the patient's respiratory circuit |
| Sham expiratory resistance | Sham comparator | Device: Sham expiratory resistanceSham resistance will be added to the patient's respiratory circuit |
Who may qualify
- Ages
- 21 to 70 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (1 listed)
- Presence of obstructive sleep apnea (AHI>10/hr)
Key exclusion criteria (4 listed)
- Serious co-morbidities including lung disease, heart disease, renal disease
- Medications affecting respiration or sleep
- Expiratory flow limitation (EFL) subgroup inclusion criteria: presence of clear EFL on polysomnographic study (reduced flow and increased pharyngeal pressure during expiration as a predominant cause of airflow obstruction).
- non-EFL subgroup inclusion criteria: complete absence of EFL on polysomnographic study
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Expiratory resistanceAlso: Expiratory positive pressureGeneric expiratory resistance will be added to the patient's respiratory circuit | Device | Expiratory resistance |
| Sham expiratory resistanceSham expiratory resistance will be added to the patient's respiratory circuit | Device | Sham expiratory resistance |
Primary outcome
Increase in ventilation (L/min) from baseline
Time frame: Acutely (1 min)
2 secondary outcomes
Increase in time to arousal from sleep
Time frame: Acutely (1 min)
Reduction in frequency of respiratory events (apnea-hypopnea index, 3% desat/arousal; NREM supine)
Time frame: Acutely (1 hour)
Results and safety
The study was withdrawn before enrolling participants, so there are no results.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 8 Sep 2026.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Andrew Wellman, PhD MD principal investigator
Brigham and Women's Hospital
Questions about this trial
What is this clinical trial studying?
A study testing Expiratory resistance in people with Obstructive Sleep Apnea, run by Brigham and Women's Hospital.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 1 inclusion and 4 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: withdrawn, as of the sponsor's last update on 8 Sep 2026. Status can change between updates, so confirm with the study contact before making plans.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study was withdrawn before enrolling participants, so there are no results.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Increase in ventilation (L/min) from baseline (time frame: Acutely (1 min)). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 8 Sep 2026.