Mechanisms of Pharyngeal Collapse in Sleep Apnea, Study D

Study Overview
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Brief Summary
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In obstructive sleep apnea (OSA), the upper airway recurrently closes during sleep. The mechanisms that lead to airway closure are not completely understood. Some studies have shown that there is progressive narrowing of the pharyngeal airway across breaths during expiration (Progressive Expiratory Narrowing, PEN) preceding an obstructive apnea. The investigators will assess the viscoelastic properties of the pharyngeal airway and its role in PEN.

Detailed Description
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In obstructive sleep apnea, the upper airway recurrently closes during sleep. The mechanisms that lead to airway closure are not completely understood. Some studies have shown that there is progressive narrowing of the pharyngeal airway across breaths during expiration (Progressive Expiratory Narrowing, PEN) preceding an obstructive apnea. The investigators will test how the viscoelastic properties of the airway influence PEN. To this end, the investigators will visualize the pharynx of sleep apnea patients using a thin endoscope and will induce central apneas during sleep. Pharyngeal cross-sectional area will be recorded during incremental changes in pharyngeal pressure during central apneas.

Official Title
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Mechanisms of Pharyngeal Collapse in Sleep Apnea, Study D

Conditions
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Sleep Apnea

Intervention / Treatment
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* Other: Induced central apneas


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Normal subjects or patients with OSA Exclusion Criteria: Any unstable cardiac condition (other than well controlled hypertension) or pulmonary problems. Any medication known to influence breathing, sleep/arousal or muscle physiology Concurrent sleep disorders (insomnia, narcolepsy, central sleep apnea or parasomnia) Claustrophobia Inability to sleep supine Allergy to lidocaine or oxymetazoline hydrochloride For women: Pregnancy

Ages Eligible for Study
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Minimum Age: 21 Years
Maximum Age: 65 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Other
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Viscoelastic properties of the airway<br> | Other: Induced central apneas<br> <br> |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Upper airway elasticity | The investigators will determine elasticity of the upper airway during induced central apneas by dividing the change in airway pressure by the change in airway cross-sectional area. The time frame for the outcome of this study is equal to the duration of the induced central sleep apnea (usually less than 40 seconds). | 10 - 40 seconds | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Sleep Apnea, Pathophysiology