Mechanisms of Pharyngeal Collapse in Sleep Apnea, Study C
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.
|Study Design:||Intervention Model: Single Group Assignment
Masking: Open Label
|Official Title:||Mechanisms of Pharyngeal Collapse in Sleep Apnea, Study C|
- Difference in peak inspiratory flow [ Time Frame: 10 - 15 seconds ] [ Designated as safety issue: No ]
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).
|Study Start Date:||December 2012|
|Estimated Study Completion Date:||December 2014|
|Estimated Primary Completion Date:||December 2014 (Final data collection date for primary outcome measure)|
Experimental: Gas mixture administration
Subjects will breathe different gas mixtures with different densities and viscosity for brief periods in order to promote changes in peak inspiratory flow
Other: Administration of gas mixtures
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.
|Contact: Pedro R Genta, MD||(617) firstname.lastname@example.org|
|Contact: Lauren B Hess, BS||(617) email@example.com|
|United States, Massachusetts|
|Brigham and Women's Hospital||Recruiting|
|Boston, Massachusetts, United States, 02115|
|Sub-Investigator: Pedro R Genta, MD|
|Principal Investigator:||David A Wellman, MD||Brigham and Women's Hospital|