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Estimating Apnea Phenotypes From Polysomnography: Oxygen (PSGtraits-O2)

This study has been completed.
ClinicalTrials.gov Identifier:
First Posted: December 18, 2012
Last Update Posted: December 7, 2017
The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details.
National Heart, Lung, and Blood Institute (NHLBI)
American Heart Association
Information provided by (Responsible Party):
Scott Aaron Sands, Brigham and Women's Hospital
This study seeks to employ advanced methods to estimate the individual factors contributing to sleep apnea from standard recordings made during routine clinical sleep studies. This study focuses on breathing control or "loop gain" as one of the factors contributing to sleep apnea. Increased levels of oxygen in the air is known to make breathing more stable by lowering "loop gain". Here, our goal is to use a new method capable of detecting a reduction in loop gain with oxygen. The investigators also aim to test whether a high loop gain measured at baseline/placebo predicts a greater improvement in sleep apnea with oxygen therapy.

Condition Intervention
Sleep Apnea Drug: Inspired oxygen (40%) Other: Sham

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Single (Participant)
Primary Purpose: Treatment
Official Title: Estimating Apnea Phenotypes From Routine Polysomnography: Application to Oxygen Therapy

Resource links provided by NLM:

Further study details as provided by Scott Aaron Sands, Brigham and Women's Hospital:

Primary Outcome Measures:
  • The reduction in severity of sleep apnea (Apnea-Hypopnea Index, Events/hour) [ Time Frame: 1 night ]

    Acute change in AHI is taken as the difference between values on the sham and oxygen nights, taken approximately 1 week apart.

    Hypopneas are based on 30% reduction in airflow (sensitivity analysis will employ criteria using 3% desaturation and arousals)

    1-way RM ANOVA will assess the reduction in AHI in patients with higher (>=0.7) and lower loop gain (<0.7); an interaction between treatment and group may indicate a preferential benefit of oxygen in those with higher loop gain.

    The percentage of the night that is not interrupted by events and arousals will also be assessed (stable breathing).

Secondary Outcome Measures:
  • Overnight change in chemosensitivity [ Time Frame: 1 night ]
    The rise in chemosensitivity overnight will be compared between sham and oxygen treatment arms using dynamic CO2 stimulation.

  • Subjective sleepiness/alertness (Stanford Sleepiness Scale) [ Time Frame: 1 night ]
    Assessed in the morning after the single night of oxygen/air, and compared between sham and oxygen studies.

  • Overnight change in blood pressure [ Time Frame: 1 night ]
    The change in blood pressure overnight will be assessed in both studies, and compared between sham and oxygen studies approximately 1 week apart.

  • Subjective sleep quality (oxygen vs sham) [ Time Frame: 1 night ]
    Better(+1)/Same(0)/Worse(-1) on oxygen vs sham

  • Frequency of EEG arousals (events per hour) [ Time Frame: 1 night ]
    To complement findings of changes in AHI, we will examine the frequency of arousals from sleep. The proportion of light sleep will also be assessed.

Enrollment: 47
Study Start Date: November 2012
Study Completion Date: July 2016
Primary Completion Date: July 2016 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: Oxygen First
Participants participate in inspired oxygen arm (40% oxygen) first, then the air night (21% oxygen) second
Drug: Inspired oxygen (40%)
Supplemental oxygen at approximately 40% e.g. via Pink venturi mask
Other Name: Supplemental oxygen
Placebo Comparator: Air First
Participants participate in the air night (sham) first, then the oxygen night second.
Other: Sham
Medical air with 21% oxygen e.g. via Pink venturi mask
Other Name: Medical air

Detailed Description:
In a single-blinded randomized crossover study, inspired oxygen/air (40%/21%) is delivered on two separate nights. Loop gain is measured from routine polysomnography using a novel mathematical method. A value of loop gain >1 reflects unstable breathing, and a value less than but approaching 1 denotes a system more prone to oscillate. Loop gain is measured as the changes in ventilatory drive/effort that arises subsequent to changes in ventilation (e.g. due to obstructive apnea). A simple chemoreflex model (gain, time constant, delay) is fit to surrogate ventilation data (derived from airflow) during sleep. The best model is one that best matches the elevated ventilatory drive (measured as ventilation in the absence of airflow obstruction) based on the prior apneic/hypopneic fall in ventilation. Loop gain is calculated from this model. We aim to use loop gain measured on and off oxygen to determine whether a strong response (reduction in apnea severity) can be predicted by a higher loop gain (in the sham arm) using our method. A majority subset of subjects will attend for detailed phenotyping of sleep apnea to assess upper airway anatomy/collapsibility, dilator muscle responsiveness, loop gain and the arousal threshold.

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Ages Eligible for Study:   20 Years to 79 Years   (Adult, Senior)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • Apnea/hypopnea index >20 events per hour
  • Age 20-79 years

Exclusion Criteria:

  • COPD with desaturation (resting SpO2<96%)
  • Use of respiratory stimulants or depressants
  • Pregnancy
  Contacts and Locations
Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT01751971

United States, Massachusetts
Brigham and Women's Hospital
Boston, Massachusetts, United States, 02115
Sponsors and Collaborators
Brigham and Women's Hospital
National Heart, Lung, and Blood Institute (NHLBI)
American Heart Association
Principal Investigator: SCOTT A Sands, PhD Brigham and Women's Hospital
  More Information

Responsible Party: Scott Aaron Sands, Instructor in Medicine, Brigham and Women's Hospital
ClinicalTrials.gov Identifier: NCT01751971     History of Changes
Other Study ID Numbers: 2005P001296-O2PSG
R01HL090897 ( U.S. NIH Grant/Contract )
First Submitted: December 12, 2012
First Posted: December 18, 2012
Last Update Posted: December 7, 2017
Last Verified: July 2016

Additional relevant MeSH terms:
Respiration Disorders
Respiratory Tract Diseases
Signs and Symptoms, Respiratory
Signs and Symptoms