How different CPAP mask exhaust flows affect CO2 rebreathing
Official title: Assessment of Circuit Rebreathing During Continuous Positive Airway Pressure (CPAP) Therapy
Run by Brigham and Women's Hospital · NCT07062770 · Data updated 2026-11-12
This test will see if different CPAP mask exhaust flows change how much exhaled carbon dioxide people with moderate to severe OSA might rebreathe during sleep.
Quick facts
| Study type | Interventional |
|---|---|
| Ages | 21 Years to 70 Years |
| Sex | All |
| Enrollment | 13 (estimated) |
| Sponsor | Brigham and Women's Hospital Academic / other |
| Locations | 1 site (Boston, Massachusetts) |
| Status | Recruiting |
| Started | May 27, 2025 |
| Main results expected | December 1, 2025 |
| Study ends | December 1, 2025 |
| Registry record updated | July 14, 2025 |
| Trial ID | NCT07062770 on ClinicalTrials.gov |
Is this trial a fit for you?
✓Likely a good fit
Adults 21 to 70 years old with moderate to severe OSA (AHI > 20), BMI 18–40 kg/m2, and current or prior CPAP use with maximum pressure <= 13 cmH2O are ideal candidates.
✕Probably not a fit
People who mouth-breathe severely, require nocturnal supplemental oxygen or other ventilatory support, have severe cardiovascular or pulmonary disease, or have another unstable sleep disorder are unlikely to benefit or be eligible.
A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.
What this trial studies
This study measures how varying CPAP mask exhaust port flows and two pressure settings affect rebreathing of exhaled CO2 in adults with moderate to severe obstructive sleep apnea. Participants will undergo wake and sleep monitoring while researchers record flow-adjusted end-tidal O2 (PetO2) and CO2 (PetCO2) across a series of defined exhaust flow conditions at 5 and 10 cmH2O, plus a zero-pressure control. The primary comparison examines flow-adjusted inspired oxygen fraction (FiO2) between two 5 cmH2O exhaust-flow conditions (5B vs 5D) during wakefulness and sleep. The protocol enrolls CPAP-experienced adults aged 21–70 with AHI > 20 and uses overnight physiological monitoring at a single center.
Why it matters
Potential benefit: If successful, results could guide mask design or settings to reduce CO2 rebreathing and improve CPAP safety and comfort.
How similar studies have gone: Prior small physiological studies have measured mask rebreathing and CO2 during noninvasive ventilation, but this systematic exhaust-flow comparison in CPAP-treated OSA is relatively novel.
Who can join: the full rules
Show full inclusion / exclusion criteria
Inclusion Criteria: * Moderate to severe OSA (AHI\>20) * Self-reported CPAP users or have previously used CPAP * Self-reported holding pressure of maximum 13 cmH2O (if known) * Age: 21-70 * BMI: 18-40 kg/m2 Exclusion Criteria: * Self-reported severe mouth-breathing * Requirement for nocturnal supplemental oxygen or other ventilatory support * Severe cardiovascular or pulmonary disease * Any unstable or acute medical condition * Any additional sleep disorder, including insomnia, except for OSA.
Where it's running
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Brigham and Women's Hospital
Boston, Massachusetts, United States Recruiting
Study contacts
- Principal investigator: Atqiya Aishah, PhD — Harvard Medical School & Brigham and Women's Hospital
- Study coordinator: Atqiya Aishah, PhD
- Email: aaishah@bwh.harvard.edu
- Phone: 857 396 3808
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How to take part
- Review the eligibility criteria above with your treating physician.
- Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
- Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.