Assessment of Circuit Rebreathing During CPAP Therapy

Mass General Brigham

Status: Enrolling

Conditions: Obstructive Sleep Apnea (OSA)

Treatments: Device: Continuous positive airway pressure (CPAP); Other: Mask exhaust port flow

Study type: Interventional

Funder types: Other

Identifiers

NCT07062770

2025P000798

Details and patient eligibility

About

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).

Full 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.

Enrollment: 13 estimated patients

Sex: All

Ages: 21 to 70 years old

Volunteers: No Healthy Volunteers

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.

Trial design

Primary purpose: Other

Allocation: Randomized

Interventional model: Sequential Assignment

Masking: Single Blind

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13 participants in 11 patient groups, including a placebo group

5 cmH2O with 35L/s

Experimental group

Description:

35 L/s exhaust flow with 5 cmH₂O PAP

Treatment:

Other: Mask exhaust port flow

Device: Continuous positive airway pressure (CPAP)

5 cmH2O with 23L/s

Experimental group

Description:

23 L/s exhaust flow with 5 cmH₂O PAP

Treatment:

Other: Mask exhaust port flow

Device: Continuous positive airway pressure (CPAP)

5 cmH2O with 18L/s

Experimental group

Description:

18 L/s exhaust flow with 5 cmH₂O PAP

Treatment:

Other: Mask exhaust port flow

Device: Continuous positive airway pressure (CPAP)

5 cmH2O with 13L/s

Experimental group

Description:

13 L/s exhaust flow with 5 cmH₂O PAP

Treatment:

Other: Mask exhaust port flow

Device: Continuous positive airway pressure (CPAP)

5 cmH2O with 8L/s

Experimental group

Description:

8 L/s exhaust flow with 5 cmH₂O PAP

Treatment:

Other: Mask exhaust port flow

Device: Continuous positive airway pressure (CPAP)

0 cmH2O with 35L/s

Placebo Comparator group

Description:

35 L/s exhaust flow with 0 cmH₂O PAP

Treatment:

Other: Mask exhaust port flow

10 cmH2O with 35L/s

Experimental group

Description:

35 L/s exhaust flow with 10 cmH₂O PAP

Treatment:

Other: Mask exhaust port flow

Device: Continuous positive airway pressure (CPAP)

10 cmH2O with 23L/s

Experimental group

Description:

23 L/s exhaust flow with 10 cmH₂O PAP

Treatment:

Other: Mask exhaust port flow

Device: Continuous positive airway pressure (CPAP)

10 cmH2O with 18L/s

Experimental group

Description:

18 L/s exhaust flow with 10 cmH₂O PAP

Treatment:

Other: Mask exhaust port flow

Device: Continuous positive airway pressure (CPAP)

10 cmH2O with 13L/s

Experimental group

Description:

13 L/s exhaust flow with 10 cmH₂O PAP

Treatment:

Other: Mask exhaust port flow

Device: Continuous positive airway pressure (CPAP)

10 cmH2O with 8L/s

Experimental group

Description:

8 L/s exhaust flow with 10 cmH₂O PAP

Treatment:

Other: Mask exhaust port flow

Device: Continuous positive airway pressure (CPAP)