The Effect of Mouth Closure on Airflow in OSA

The Heterogeneous Effects of Mouth Closure on Airflow in Patients With Obstructive Sleep Apnea

Mouth breathing is associated with increased airway resistance, pharyngeal collapsibility, and obstructive sleep apnea (OSA) severity. It is commonly believed that closing the mouth can mitigate the negative effects of mouth breathing during sleep. However, we propose that mouth breathing serves as an essential route bypassing obstruction along the nasal route (e.g., velopharynx). The present study investigates the role of mouth breathing as an essential route in some OSA patients and its association with upper airway anatomical factors.

Participants underwent drug-induced sleep endoscopy (DISE) with simultaneous pneumotach airflow measurements through the nose and mouth separately. During the DISE procedure, alternating mouth closure (every other breath) cycles were performed during flow-limited breathing.

We evaluated the overall effect mouth closure on inspiratory airflow, and the change in inspiratory airflow with mouth closure across three mouth-breathing quantiles. We also evaluated if velopharyngeal obstruction was associated with mouth breathing and a negative airflow response to mouth closure.

Study Overview

• Status: Completed
• Conditions: Hypopnea, Sleep
• Intervention / Treatment: Other: Mouth closure

• Study Type: Interventional
• Enrollment (Actual): 66
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Massachusetts
    • Boston, Massachusetts, United States, 02115
      • Brigham and Women's Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Diagnosed obstructive sleep apnea (AHI > 5 events/h).
• Scheduled to undergo clinical drug-induced sleep endoscopy.

Exclusion Criteria:

• pregnancy
• age under 18 years
• poor general health
• allergy to propofol or dexmedetomidine
• history of surgical treatment for sleep apnea, such as palate, tongue base, or epiglottis surgery.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Non-Randomized
• Interventional Model: Crossover Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Mouth closed; Closing the mouth by applying pressure to the mentum until the teeth were in occlusion, without altering the head position. Performed during flow-limited breathing.	Other: Mouth closure; Closing the mouth during sleep by applying pressure to the mentum until the teeth were in occlusion, without altering the head position.
No Intervention: Mouth relaxed; Mouth in the natural relaxed position during sleep.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Total inspiratory flow	Change in airflow in the transition from mouth relaxed to mouth closed (intervention).	1 day - the intervention of mouth closure on the outcome is applied acutely on alternating breaths, such that the effect of mouth closure is assessed based on the experiment which occurs in a single day.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in total inspiratory airflow with mouth closure	We analyzed the change in total inspiratory flow within three quantiles of roughly equal sample sizes based on oral breathing; quantile 1: oral airflow <0.05 L/min, quantile 2: oral airflow between 0.05 and 2.2 L/min, and quantile 3: oral airflow >2.2 L/min. We also analyzed the effect of velopharyngeal obstruction on the change in total inspiratory airflow.	1 day - the intervention of mouth closure is applied acutely on alternating breaths, such that the effect of mouth closure on the outcome is assessed based on the experiment which occurs in a single day.

Collaborators and Investigators

• Sponsor: Brigham and Women's Hospital
• Collaborators: National Heart, Lung, and Blood Institute (NHLBI); Massachusetts Eye and Ear Infirmary

Study record dates

Study Major Dates

• Study Start (Actual): December 17, 2021
• Primary Completion (Actual): July 10, 2022
• Study Completion (Actual): July 10, 2022

Study Registration Dates

• First Submitted: August 1, 2024
• First Submitted That Met QC Criteria: August 6, 2024
• First Posted (Actual): August 9, 2024

Study Record Updates

• Last Update Posted (Actual): August 9, 2024
• Last Update Submitted That Met QC Criteria: August 6, 2024
• Last Verified: August 1, 2024

More Information

Terms related to this study

• Keywords: Obstructive sleep apnea; Upper airway; Drug-induced sleep endoscopy; Mouth breathing
• Additional Relevant MeSH Terms: Nervous System Diseases; Respiratory Tract Diseases; Apnea; Respiration Disorders; Sleep Disorders, Intrinsic; Dyssomnias; Sleep Wake Disorders; Sleep Apnea Syndromes
• Other Study ID Numbers: 2019P002847; R01HL128658 (U.S. NIH Grant/Contract)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: We do not plan to make the IPD available to other researchers.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No