Obstructive Sleep-Disordered Breathing(Archived)

Excerpt

Obstructive sleep-disordered breathing (SDB) is not a distinct disease, but rather a syndrome of upper airway dysfunction during sleep characterized by snoring and/or increased respiratory effort secondary to increased upper airway resistance and pharyngeal collapsibility. Obstructive Sleep Apnea (OSA), also referred to as obstructive sleep apnea-hypopnea, is a sleep disorder that involves cessation or a significant decrease in airflow in the presence of breathing effort.

1. Apnea is defined as the cessation of airflow for ten or more seconds.

1. Hypopnea is defined as a recognizable, transient reduction, but not a complete cessation of, breathing for ten or more seconds.

1. Apnea–hypopnea index (AHI) is the most commonly reported polysomnographic parameter describing SDB severity.

The term “obstructive SDB” is used when symptoms of intermittent upper airway obstruction during sleep are present, but the severity of airway obstruction has not been defined by objective measures such as polysomnography.

The general characteristic of Obstructive Sleep Apnea is the increased collapsibility of the upper airway during sleep resulting in markedly reduced (hypopnea) or absent (apnea) airflow at the nose and/or mouth which is usually accompanied by oxyhemoglobin desaturation and is typically terminated by a brief micro-arousal.

Repeated episodes of apnea lead to a sustained reduction in oxyhemoglobin saturation and sleep fragmentation with diminished amounts of slow-wave and rapid eye movement (REM) sleep.