Cough Reflex and Obstructive Sleep Apnea Syndrome
Cough Reflex and Obstructive Sleep Apnea Syndrome
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).
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.
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