Cough Reflex and Obstructive Sleep Apnea Syndrome

Study Overview
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Brief Summary
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Up to 70% of obese patients undergoing bariatric surgery have obstructive sleep apnea syndrome (OSAS). OSAS is responsible for laryngeal sensory impairment. As the afferent neural pathway involved in the initiation of cough is located in the laryngeal epithelium, cough reflex sensitivity may be decreased in obese OSAS patients. The researchers therefore conducted this study to determine the effect of OSAS associated with obesity on cough reflex sensitivity, assessed by cough reflex threshold to an inhaled irritant (citric acid).

Detailed Description
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Obese patients undergoing scheduled bariatric surgery underwent a cough challenge as part of their routine preoperative evaluation. Patients were classified as presenting OSAS if apnea-hypopnea index obtained from preoperative full-night polysomnography was greater than 5/hour. Cough threshold was measured with citric acid. Increasing concentrations of mouth- nebulized citric acid (2.5, 5, 10, 20, 40, 80, 160, 320 and 640 mg/mL) were delivered during inspiration until a cough was elicited. The citric acid concentration eliciting one cough (C1) was defined as the cough reflex threshold.

Official Title
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Effect of Obstructive Sleep Apnea Syndrome Associated With Obesity on Cough Reflex Threshold to Citric Acid

Conditions
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Sleep Apnea Syndrome

Intervention / Treatment
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* Procedure: Cough reflex test


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Obese patient scheduled to undergo bariatric surgery Exclusion Criteria: Age less than 18 Active smoking Psychotropic medication Angiotensin-converting enzyme inhibitor or angiotensin II receptor antagonist medication Pregnancy Anesthesia or endotracheal intubation during the previous month Allergic rhinitis Upper airway or bronchopulmonary infection during the previous month Chronic cough Chronic respiratory disease Pharyngolaryngeal disease Neurological disease

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Diagnostic
Allocation: Non-Randomized
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Intervention/Treatment |
| --- |
|Procedure: Cough reflex test|nan|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| To compare cough reflex threshold to citric acid between obese OSAS patients and obese non-OSAS patients |  |  | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| To correlate OSAS severity assessed by apnea-hypopnea index and cough reflex threshold to citric acid |  |  | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Cough Reflex, Citric acid, Obesity, Sleep apnea syndrome