Assessment of Circuit Rebreathing During CPAP Therapy

Not Applicable

Recruiting

• Conditions: Obstructive Sleep Apnea (OSA)

• Registration Number: NCT07062770
• Lead Sponsor: Brigham and Women's Hospital

Brief Summary

The goal of this research is to better understand how different CPAP mask designs affect airflow and rebreathing of exhaled carbon dioxide (CO₂) during sleep in individuals with obstructive sleep apnea (OSA).

Detailed Description

To understand the existence and severity of circuit rebreathing during treatment with continuous positive airway pressure (CPAP) using different sizes of the exhaust ports in individuals with obstructive sleep apnea (OSA).

Flow-adjusted end-tidal oxygen (PetO2) and carbon dioxide (PetCO2) will be assessed to determine the magnitude of hypoxic load during both wakefulness and sleep. To systematically assess these conditions, the conditions were defined as follows:

* 5A: 35 L/s exhaust flow with 5 cmH₂O PAP

* 5B: 23 L/s exhaust flow with 5 cmH₂O PAP

* 5C: 18 L/s exhaust flow with 5 cmH₂O PAP

* 5D: 13 L/s exhaust flow with 5 cmH₂O PAP

* 5E: 8 L/s exhaust flow with 5 cmH₂O PAP

* 0P: 35 L/s exhaust flow with 0 cmH₂O PAP

* 10A: 35 L/s exhaust flow with 10 cmH₂O PAP

* 10B: 23 L/s exhaust flow with 10 cmH₂O PAP

* 10C: 18 L/s exhaust flow with 10 cmH₂O PAP

* 10D: 13 L/s exhaust flow with 10 cmH₂O PAP

* 10E: 8 L/s exhaust flow with 10 cmH₂O PAP Primary endpoint is to evaluate the effect of exhaust flow on flow-adjusted average inspired oxygen fraction (FiO₂) during (1) wakefulness and (2) sleep between 5B vs. 5D.

Study Timeline

• Study Start: 2025-05-27
• Study First Submitted: 2025-05-27
• Status Verified: 2025-07
• Study First Submitted QC: 2025-07-10
• Last Update Submitted: 2025-07-10
• Study First Posted: 2025-07-14
• Last Update Posted: 2025-07-14
• Primary Completion: 2025-12-01
• Study Completion: 2025-12-01

Recruitment & Eligibility

• Status: RECRUITING
• Sex: All
• Target Recruitment: 13

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.

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: SEQUENTIAL

Primary Outcome Measures

Name	Time	Method
Change in flow-adjusted average inspired oxygen fraction (FiO₂) during wake.	through study completion, an average of 1 year	Difference in FiO2 between 23L/s vs 13L/s exhaust flow at 5 cmH2O PAP.
Change in flow-adjusted average inspired oxygen fraction (FiO₂) during sleep.	through study completion, an average of 1 year	Difference in FiO2 between 23L/s vs 13L/s exhaust flow at 5 cmH2O PAP.

Secondary Outcome Measures

Name	Time	Method
Impact on hypoxic burden during sleep.	through study completion, an average of 1 year	Difference in hyboxic burden between 23L/s vs 13L/s exhaust flow at 5 cmH2O PAP.

Trial Locations

Locations (1)

Brigham and Women's Hospital; 🇺🇸 Boston, Massachusetts, United States