INTRODUCTION
Obstructive sleep apnea syndrome (OSAS) is a
respiratory disorder characterized by repeated episodes
of flow limitation or complete cessation of flow due to
partial narrowing or complete occlusion of the pharyngeal
airway during sleep.1 These respiratory events are
followed by alterations in gas exchange arousals leading
to disruption of normal sleep pattern.
OSAS affects 2% to 4% of children in the general
population.2 However, obese children have a much higher
prevalence of the disorder that may approach 50%.3–5
Thus, obesity is an important risk factor for the development
of OSAS in children. Several studies suggest that
particular anatomical factors around the pharyngeal airway
in obese children, including lymphoid and parapharyngeal
fat pad tissues, induce sleep apnea by narrowing
the upper airway.6–8 For a given inspiratory flow rate in
the airway, increased airway resistance anterior to a
given point in the airway will increase the magnitude of
negative pressure loading at that point, favoring its narrowing
and/or collapse. Additionally, this will be facilitated
if there is no increased reflex activation of airway
to maintain the airway patency. Distal to the choanae,
the pharynx is particularly liable to collapse, especially in
the region of the soft palate, tonsils, and adenoids. Likewise,
the oropharynx is susceptible to collapse due to the
tongue, tonsils, and the distensible nature of the surrounding
structures comprising the airway.
INTRODUCTIONObstructive sleep apnea syndrome (OSAS) is arespiratory disorder characterized by repeated episodesof flow limitation or complete cessation of flow due topartial narrowing or complete occlusion of the pharyngealairway during sleep.1 These respiratory events arefollowed by alterations in gas exchange arousals leadingto disruption of normal sleep pattern.OSAS affects 2% to 4% of children in the generalpopulation.2 However, obese children have a much higherprevalence of the disorder that may approach 50%.3–5Thus, obesity is an important risk factor for the developmentof OSAS in children. Several studies suggest thatparticular anatomical factors around the pharyngeal airwayin obese children, including lymphoid and parapharyngealfat pad tissues, induce sleep apnea by narrowingthe upper airway.6–8 For a given inspiratory flow rate inthe airway, increased airway resistance anterior to agiven point in the airway will increase the magnitude ofnegative pressure loading at that point, favoring its narrowingand/or collapse. Additionally, this will be facilitatedif there is no increased reflex activation of airwayto maintain the airway patency. Distal to the choanae,the pharynx is particularly liable to collapse, especially inthe region of the soft palate, tonsils, and adenoids. Likewise,the oropharynx is susceptible to collapse due to thetongue, tonsils, and the distensible nature of the surroundingโครงสร้างที่ประกอบด้วยการจำกัด(มหาชน)
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