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

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ClinicalTrials.gov Identifier: NCT01751971
Recruitment Status : Completed
First Posted : December 18, 2012
Results First Posted : January 8, 2018
Last Update Posted : January 8, 2018
Sponsor:
Collaborators:
National Heart, Lung, and Blood Institute (NHLBI)
American Heart Association
Information provided by (Responsible Party):
Scott Aaron Sands, Brigham and Women's Hospital

Brief Summary:
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 or disease Intervention/treatment
Sleep Apnea Drug: Inspired oxygen (40%) Other: Sham

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. We also assessed whether assessing upper airway anatomy/collapsibility, dilator muscle responsiveness, and the arousal threshold helped to predict responses to treatment.

Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 47 participants
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Single (Participant)
Masking Description: Participants were not informed whether they were breathing supplemental inspired oxygen or sham (air) on the study night. Technicians and investigators performing the study were not masked in order to carefully ensure delivery of treatment.
Primary Purpose: Treatment
Official Title: Estimating Apnea Phenotypes From Routine Polysomnography: Application to Oxygen Therapy
Study Start Date : November 2012
Primary Completion Date : July 2016
Study Completion Date : July 2016

Resource links provided by the National Library of Medicine

MedlinePlus related topics: Oxygen Therapy
U.S. FDA Resources

Arm Intervention/treatment
Active Comparator: Inspired Oxygen First
Participants breathe air with additional inspired oxygen (40%) for 1 night during an overnight sleep study (15 L/min via venturi mask). 1 week later participants will crossover to Sham (sham comparator).
Drug: Inspired oxygen (40%)
Supplemental oxygen at 40% inspired via venturi mask (15 L/min). Equivalent to 5 L/min via nasal cannula.
Other Name: Supplemental oxygen
Other: Sham
Medical air with 21% oxygen via venturi mask (15 L/min).
Other Name: Medical air
Sham Comparator: Sham First
Participants breathe air without additional inspired oxygen for 1 night during sleep (15 L/min via Venturi mask). 1 week later participants will crossover to Inspire Oxygen (active intervention).
Drug: Inspired oxygen (40%)
Supplemental oxygen at 40% inspired via venturi mask (15 L/min). Equivalent to 5 L/min via nasal cannula.
Other Name: Supplemental oxygen
Other: Sham
Medical air with 21% oxygen via venturi mask (15 L/min).
Other Name: Medical air



Primary Outcome Measures :
  1. Apnea-hypopnea Index [ Time Frame: 1 night ]

    Apnea-hypopnea index (AHI) will be compared between oxygen and sham nights. Hypopneas are based on 30% reduction in airflow (no desaturation or arousal criteria). AHI data are exclusive to non-REM supine sleep.

    The results presented here are for the AHI at each intervention ("per intervention") regardless of the sequence (preferred clinicaltrials.gov format).

    Please note, however, that the a priori outcome measure was the reduction in AHI with oxygen as a percent of sham values, i.e. (AHI on sham - AHI on oxygen)/(AHI on sham) % (a comparison with greater statistical power), compared between patient subgroups (see Statistical Analysis section).

    Subgroups were defined a priori as higher (>=0.7) versus lower loop gain (<0.7), but tests were also performed in subgroups defined by "favorable" versus "unfavorable" pathophysiology.



Secondary Outcome Measures :
  1. Frequency of EEG Arousals (Events Per Hour) [ Time Frame: 1 night ]
    Frequency of scored EEG arousals per hour of non-REM sleep. Note: Our objective was to describe changes in secondary outcomes within phenotypic subgroups. Overall effects (unselected patients / ignoring phenotypic subgroups) are first presented below, followed by effects in favorable vs. unfavorable subgroups.

  2. Overnight Change in Systolic Blood Pressure [ Time Frame: 1 night ]
    The change in systolic blood pressure overnight. Two supine oscillometric measurements of blood pressure are made: just prior to lights out (evening), and after lights on (morning).

  3. Overnight Change in Diastolic Blood Pressure [ Time Frame: 1 night ]
    The change in diastolic blood pressure overnight. Two supine oscillometric measurements of blood pressure are made: just prior to lights out (evening), and after lights on (morning).

  4. Subjective Sleep Quality (Oxygen vs Sham) [ Time Frame: 1 night ]
    Better(+1)/Same(0)/Worse(-1) on oxygen vs sham, i.e. "a relative comparison between arms". When subjects had completed the entire study, they were asked to compare subjectively their sleep quality on the first versus second study.

  5. Subjective Sleepiness/Alertness (Stanford Sleepiness Scale) [ Time Frame: 1 night ]
    Assessed in the morning after the single night of treatment. Minimum score: 1 (alert), maximum score: 7 (not alert).



Information from the National Library of Medicine

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

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

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


Locations
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
Investigators
Principal Investigator: SCOTT A Sands, PhD Brigham and Women's Hospital

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 Posted: December 18, 2012    Key Record Dates
Results First Posted: January 8, 2018
Last Update Posted: January 8, 2018
Last Verified: December 2017

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