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

This study is currently recruiting participants.
Verified July 2013 by Brigham and Women's Hospital
American Heart Association
Information provided by (Responsible Party):
David Andrew Wellman, Brigham and Women's Hospital Identifier:
First received: December 12, 2012
Last updated: July 29, 2013
Last verified: July 2013

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%)

Study Type: Interventional
Study Design: Allocation: Randomized
Endpoint Classification: Efficacy Study
Intervention Model: Crossover Assignment
Masking: Single Blind (Subject)
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 Brigham and Women's Hospital:

Primary Outcome Measures:
  • The reduction in severity of sleep apnea (Apnea-Hypopnea Index, Events/hour) [ Time Frame: 1 night ] [ Designated as safety issue: No ]
    Acute change in AHI is taken as the difference between values on the sham and oxygen nights, taken approximately 1 week apart.

Secondary Outcome Measures:
  • Overnight change in chemosensitivity [ Time Frame: 1 night ] [ Designated as safety issue: No ]
    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 ] [ Designated as safety issue: No ]
    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 ] [ Designated as safety issue: No ]
    The change in blood pressure overnight will be assessed in both studies, and compared between sham and oxygen studies approximately 1 week apart.

Estimated Enrollment: 10
Study Start Date: November 2012
Estimated Study Completion Date: April 2014
Estimated Primary Completion Date: April 2014 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: Oxygen
Inspired oxygen at 40%
Drug: Inspired oxygen (40%)
Supplemental oxygen at approximately 40% e.g. via Pink venturi mask
Other Name: Supplemental oxygen
Placebo Comparator: Air
Placebo/Sham using air at the same flow rate

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 (1) whether our method detects a reduction in loop gain, and whether a strong response (reduction in apnea severity) can be predicted by a higher loop gain (in the sham arm) using our method.


Ages Eligible for Study:   20 Years to 79 Years
Genders Eligible for Study:   Both
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
Please refer to this study by its identifier: NCT01751971

Contact: SCOTT A SANDS, PhD 6177325619

United States, Massachusetts
Brigham and Women's Hospital Recruiting
Boston, Massachusetts, United States, 02115
Contact: Scott SANDS, PhD   
Sub-Investigator: Scott A Sands, PhD         
Sponsors and Collaborators
Brigham and Women's Hospital
American Heart Association
Principal Investigator: Andrew Wellman, MD Brigham and Women's Hospital
  More Information

No publications provided

Responsible Party: David Andrew Wellman, Instructor in Medicine, Brigham and Women's Hospital Identifier: NCT01751971     History of Changes
Other Study ID Numbers: 2005P001296-O2PSG, R01HL090897
Study First Received: December 12, 2012
Last Updated: July 29, 2013
Health Authority: United States: Institutional Review Board

Additional relevant MeSH terms:
Sleep Apnea Syndromes
Respiration Disorders
Respiratory Tract Diseases
Signs and Symptoms, Respiratory
Signs and Symptoms
Sleep Disorders, Intrinsic
Sleep Disorders
Nervous System Diseases processed this record on April 16, 2014