Cough Reflex and Obstructive Sleep Apnea Syndrome

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

Status

Completed

Phases

Study type

Interventional

Source

ClinicalTrials.gov

Registry ID

NCT00317083

Enrollment

Registered

2006-04-24

Start date

2001-11-30

Completion date

2003-02-28

Last updated

2006-04-24

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Sleep Apnea Syndrome

Keywords

Cough Reflex, Citric acid, Obesity, Sleep apnea syndrome

Brief summary

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

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.

Interventions

PROCEDURECough reflex test

Study design

Allocation

NON_RANDOMIZED

Intervention model

SINGLE_GROUP

Primary purpose

DIAGNOSTIC

Masking

NONE

Eligibility

Sex/Gender

ALL

Age

18 Years to No maximum

Healthy volunteers

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

Design outcomes

Primary

Measure	Time frame
To compare cough reflex threshold to citric acid between obese OSAS patients and obese non-OSAS patients	—

Secondary

Measure	Time frame
To correlate OSAS severity assessed by apnea-hypopnea index and cough reflex threshold to citric acid	—

Countries

France

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026