Sleep Apnea
Conditions
Keywords
Sleep apnea, Pathophysiology
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.
Interventions
OTHERAdministration of gas mixtures
Sponsors
National Heart, Lung, and Blood Institute (NHLBI)
Brigham and Women's Hospital
Study design
Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
OTHER
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
21 Years to 65 Years
Healthy volunteers
Yes
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
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| 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). |
Countries
United States
Outcome results
None listed