Mechanisms of Pharyngeal Collapse in Sleep Apnea, Study C

Not Applicable

Withdrawn

• Conditions: Sleep Apnea
• Interventions: Other: Administration of gas mixtures

• Registration Number: NCT01738022
• Lead Sponsor: Brigham and Women's Hospital

Brief Summary

In obstructive sleep apnea (OSA), the upper airway recurrently closes during sleep. The mechanisms that lead to airway closure are not completely understood. Models to study mechanisms of airway collapse have been proposed. However, these models have not been tested in the human upper airway. Gas density and viscosity are different gas properties that influence upper airway collapse and are variables of different models. In this study, subjects will breathe gas mixtures of different densities and viscosities for brief periods of time in order to test those models.

Detailed Description

Models to study mechanisms of airway collapse have been proposed. However, these models have not been tested in the human upper airway. Gas density and viscosity are different gas properties that influence upper airway collapse and are variables of different models.

In this study, subjects will breathe gas mixtures of different densities (helium and sulfur-hexafluoride) or viscosity (neon) for brief periods of time during flow-limited breaths. Flow limitation will be induced by sustained reductions of continuous positive airway pressure (CPAP). The investigators will test some models of upper airway collapse by observing if flow while breathing different gas mixtures scales according to the differences in density and viscosity.

Study Timeline

• Study First Submitted: 2012-11-14
• Study First Submitted QC: 2012-11-28
• Study First Posted: 2012-11-30
• Study Start: 2012-12-08
• Primary Completion: 2017-02-07
• Study Completion: 2017-02-07
• Status Verified: 2019-07
• Last Update Submitted: 2019-07-09
• Last Update Posted: 2019-07-11

Recruitment & Eligibility

• Status: WITHDRAWN
• Sex: All
• Target Recruitment: Not specified

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

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: SINGLE_GROUP

Arm && Interventions

Group	Intervention	Description
Gas mixture administration	Administration of gas mixtures	Subjects will breathe different gas mixtures with different densities and viscosity for brief periods in order to promote changes in peak inspiratory flow

Primary Outcome Measures

Name	Time	Method
Difference in peak inspiratory flow	10 - 15 seconds	Observed peak inspiratory flow while breathing different gas mixtures will be compared to model predicted flows.; Subjects will breathe different gas mixtures for 2 consecutive breaths only. Therefore the time frame is equal to one breath before gas mixture administration and two breaths after (usually 10-15 seconds).

Trial Locations

Locations (1)

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