Nasal Expiratory Resistance in Patients With Sleep Apnea and Expiratory Flow Limitation (ExpFLOSA)

Obstructive sleep apnea (OSA) is inherently site-specific. In a physiological controlled intervention study, the investigators seek to determine whether applying expiratory resistance can acutely improve ventilation and sleep in patients with expiratory flow limitation (EFL).

Study Overview

• Status: Terminated
• Conditions: Obstructive Sleep Apnea
• Intervention / Treatment: Device: Expiratory resistance; Device: Sham expiratory resistance

Detailed Description

Collapse of the upper airway can occur at different sites of the pharynx. One common and recognizable form of pharyngeal collapse is prolapse of the soft palate (velopharynx) on expiration, a phenomenon referred to as expiratory flow limitation (EFL). In principle, application of nasal positive expiratory pressure should reverse expiratory narrowing, increase ventilation, and prevent the subsequent progressive loss of airflow that leads to arousal from sleep, thereby improving OSA. One means to achieve this expiratory pressure is with the use of an added nasal expiratory resistance.

Accordingly, during a single night protocol, the investigators will examine the effects of increasing nasal expiratory resistance during sleep. During obstructed breathing, patients will be switched acutely, in random order, from normal conditions to an added expiratory resistance (30-80 cmH2O/L.s) or a sham resistance, for short (1 min) and prolonged periods (1 hour), repeatedly overnight.

Patients participating in the study will be divided into two groups, those exhibiting EFL versus those without EFL (i.e. with inspiratory flow limitation).

The main outcomes of the short physiologic interventions are:

• Increase in ventilation, and
• Increased time to a respiratory-related arousal from sleep, relative to sham conditions.

The main outcome of the prolonged interventions is:

--Reduced frequency of respiratory events (AHI; 3% desaturation or arousal) relative to sham conditions.

The central objective of the study is to test whether there is a greater improvement in the above outcomes in those with EFL versus those without EFL.

This data will allow us to test whether expiratory resistance is of potential therapeutic benefit specifically in patients with EFL rather than those without EFL.

• Study Type: Interventional
• Enrollment (Actual): 9
• Phase: Not Applicable

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 21 years to 70 years (ADULT, OLDER_ADULT)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Presence of obstructive sleep apnea (AHI>10/hr)

Exclusion Criteria:

• Serious co-morbidities including lung disease, heart disease, renal disease
• Medications affecting respiration or sleep

Expiratory flow limitation (EFL) subgroup inclusion criteria: presence of clear EFL on polysomnographic study (reduced flow and increased pharyngeal pressure during expiration as a predominant cause of airflow obstruction).

non-EFL subgroup inclusion criteria: complete absence of EFL on polysomnographic study

Study Plan

How is the study designed?

Design Details

• Primary Purpose: TREATMENT
• Allocation: RANDOMIZED
• Interventional Model: CROSSOVER
• Masking: SINGLE

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
EXPERIMENTAL: Expiratory resistance; Generic expiratory resistance will be added to the patient's respiratory circuit	Device: Expiratory resistance; Generic expiratory resistance will be added to the patient's respiratory circuit; Other Names: Expiratory positive pressure
SHAM_COMPARATOR: Sham expiratory resistance; Sham resistance will be added to the patient's respiratory circuit	Device: Sham expiratory resistance; Sham expiratory resistance will be added to the patient's respiratory circuit

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
Increase in ventilation (L/min) from baseline	Acutely (1 min)

Secondary Outcome Measures

Outcome Measure	Time Frame
Increase in time to arousal from sleep	Acutely (1 min)
Reduction in frequency of respiratory events (apnea-hypopnea index, 3% desat/arousal; NREM supine)	Acutely (1 hour)

Other Outcome Measures

Outcome Measure	Time Frame
Reduction in frequency of arousals from sleep	Acutely (1 hour)

Collaborators and Investigators

• Sponsor: Brigham and Women's Hospital
• Investigators: Principal Investigator: Andrew Wellman, PhD MD, Brigham and Women's Hospital

Study record dates

Study Major Dates

• Study Start (ACTUAL): May 1, 2016
• Primary Completion (ACTUAL): May 1, 2017
• Study Completion (ACTUAL): May 1, 2017

Study Registration Dates

• First Submitted: November 19, 2015
• First Submitted That Met QC Criteria: November 20, 2015
• First Posted (ESTIMATE): November 23, 2015

Study Record Updates

• Last Update Posted (ACTUAL): March 9, 2022
• Last Update Submitted That Met QC Criteria: February 23, 2022
• Last Verified: February 1, 2022

More Information

Terms related to this study

• Keywords: Obstructive sleep apnea; Expiratory flow limitation
• Additional Relevant MeSH Terms: Nervous System Diseases; Respiratory Tract Diseases; Respiration Disorders; Sleep Disorders, Intrinsic; Dyssomnias; Sleep Wake Disorders; Signs and Symptoms, Respiratory; Sleep Apnea Syndromes; Sleep Apnea, Obstructive; Apnea
• Other Study ID Numbers: 2012P000957E