Mechanisms of Pharyngeal Collapse in Sleep Apnea, Study A

Mass General Brigham

Status: Completed

Conditions: Obstructive Sleep Apnea; Pathophysiology

Treatments: Other: Pharyngeal topical anesthesia

Study type: Interventional

Funder types: Other; NIH

Identifiers

NCT01728974

2012P000957A

1R01HL102321-01A1 (U.S. NIH Grant/Contract)

Details and patient eligibility

About

In obstructive sleep apnea, the upper airway recurrently closes during sleep. The mechanisms that lead to airway closure are not completely understood. While the airway of some people narrows and airflow decreases during inspiration due to increasing inspiratory effort, others maintain constant airflow throughout inspiration. Airway neuromuscular reflexes may protect against airway narrowing that occurs due to increasing inspiratory effort. To test this hypothesis, the investigators will initially measure airway neuromuscular reflex and inspiratory flow and then attenuate neuromuscular reflex through topical pharyngeal anesthesia to observe the effects on inspiratory flow.

Full description

The mechanisms that lead to airway closure are not completely understood. While the airway of some people narrows and airflow decreases during inspiration due to increasing inspiratory effort, others maintain constant airflow throughout inspiration (negative effort dependence, NED). The investigators hypothesize that upper airway neuromuscular reflexes may protect against narrowing that occurs due to increasing inspiratory effort. Topical oropharyngeal anesthesia has been shown to reduce neuromuscular reflexes. Thus, the investigators also hypothesize that patients with stable inspiratory flow will develop NED once the reflexes have been impaired with topical anesthetic. The investigators plan to:

1. measure upper airway muscle EMG to assess how it corresponds to the presence or absence of NED. This aim will allow us to test the hypothesis that robust upper airway muscle reflexes can protect against NED.
2. reduce upper airway muscle activity and reflexes by topical oropharyngeal anesthesia. This will allow us to test the hypothesis that attenuated upper airway muscle activity induced by topical anesthesia can induce NED.

Enrollment: 26 patients

Sex: All

Ages: 21 to 65 years old

Volunteers: Accepts Healthy Volunteers

Inclusion criteria

• Normal subjects or patients with OSA

Exclusion criteria

• Any unstable cardiac condition (other than well controlled hypertension) or pulmonary problems.
• Any medication known to influence breathing, sleep/arousal or muscle physiology
• Concurrent sleep disorders (insomnia, narcolepsy, central sleep apnea or parasomnia)
• Claustrophobia
• Inability to sleep supine
• Allergy to lidocaine or oxymetazoline HCl
• For women: Pregnancy

Trial design

Primary purpose: Other

Allocation: N/A

Interventional model: Single Group Assignment

Masking: None (Open label)

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26 participants in 1 patient group

Pharyngeal topical anesthesia

Experimental group

Description:

Pharyngeal topical anesthesia will be performed using 4% lidocaine spray

Treatment:

Other: Pharyngeal topical anesthesia