Volume 24, Issue 6 pp. 582-589
Original Article

Pharyngeal distensibility during expiration is an independent predictor of the severity of obstructive sleep apnoea

Ning-Hung Chen

Corresponding Author

Ning-Hung Chen

Sleep Center, Department of Pulmonary and Critical Care Medicine, Chang Gung Memorial Hospital, Taoyuan, Taiwan

Department of Respiratory Therapy, Chang Gung University, Taoyuan, Taiwan

Correspondence: Ning-Hung Chen, Sleep Center, Department of Pulmonary and Critical Care Medicine, Chang Gung Memorial Hospital, Chang Gung University, 5, Fu-Shin Street, KweiShanShang, Taoyuan 333, Taiwan. Email: [email protected]Search for more papers by this author
Shih-Wei Lin

Shih-Wei Lin

Sleep Center, Department of Pulmonary and Critical Care Medicine, Chang Gung Memorial Hospital, Taoyuan, Taiwan

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Li-Pang Chuang

Li-Pang Chuang

Sleep Center, Department of Pulmonary and Critical Care Medicine, Chang Gung Memorial Hospital, Taoyuan, Taiwan

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Peter A. Cistulli

Peter A. Cistulli

Department of Respiratory and Sleep Medicine, Royal North Shore Hospital, Sydney, NSW, Australia

Charles Perkins Centre, Faculty of Medicine and Health, University of Sydney, Sydney, NSW, Australia

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Meng-Jer Hsieh

Meng-Jer Hsieh

Department of Respiratory Therapy, Chang Gung University, Taoyuan, Taiwan

Department of Pulmonary and Critical Care Medicine, Chang Gung Memorial Hospital, Chiayi, Taiwan

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Kuo-Chin Kao

Kuo-Chin Kao

Sleep Center, Department of Pulmonary and Critical Care Medicine, Chang Gung Memorial Hospital, Taoyuan, Taiwan

Department of Respiratory Therapy, Chang Gung University, Taoyuan, Taiwan

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Yu-Fang Liao

Yu-Fang Liao

Sleep Center, Department of Craniofacial Orthodontics, Chang Gung Memorial Hospital, Taoyuan, Taiwan

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Li-Fu Li

Li-Fu Li

Sleep Center, Department of Pulmonary and Critical Care Medicine, Chang Gung Memorial Hospital, Taoyuan, Taiwan

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Cheng-Ta Yang

Cheng-Ta Yang

Sleep Center, Department of Pulmonary and Critical Care Medicine, Chang Gung Memorial Hospital, Taoyuan, Taiwan

Department of Respiratory Therapy, Chang Gung University, Taoyuan, Taiwan

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First published: 24 January 2019
Citations: 6
(Associate Editor: David Barnes; Senior Editor: Lutz Beckert)

ABSTRACT

Background and objective

Pharyngeal distensibility and collapsibility reflect the passive properties of tissue in the airway, are an indicator of the ease with which an airway can be deformed and are related to the severity of obstructive sleep apnoea (OSA). During normal tidal respiration, the collapsibility of the pharynx during expiration is passive without confounding by neuromuscular activation that occurs during inspiration. We evaluated the distensibility and collapsibility of the upper airway in subjects with OSA during wakefulness using sophisticated dynamic computed tomography (CT) imaging. We hypothesized that the dynamic changes of the upper airway during expiration would be related to the severity of OSA.

Methods

Twenty-three patients with OSA and eight normal subjects underwent simultaneous measurement of respiratory flow and airway calibre using ultrafast CT. The change in pharyngeal cross-sectional area divided by the change in concomitant flow (as distensibility or collapsibility) was measured and compared across different severities of OSA.

Results

The slope of this relationship between delta area and delta flow during expiration was significantly higher in severe OSA when compared with normal controls and mild–moderate OSA. Differences in airway distensibility or collapsibility between severity groups were significant in expiration but not in inspiration. Distensibility or collapsibility contributed most to the apnoea–hypopnoea index in regression modelling. Age, gender, and body mass index (BMI) were not significant independent predictors.

Conclusion

Our study demonstrates that airway distensibility during the expiratory phase of awake respiration is correlated with the severity of OSA.

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