CONGENITAL CENTRAL HYPOVENTILATION SYNDROME (CCHS) OBSTRUCTIVE SLEEP APNEA

IDIOPATHIC HYPOVENTILATION CONGENITAL CENTRAL HYPOVENTILATION SYNDROME (CCHS)

Obstructive Sleep Apnea (OSA) syndrome is characterized by recurrent airflow cessation caused by the collapse of the upper airway despite continuing respiratory efforts. Because of its prevalence and association with neurocognitive and cardiovascular morbidity, it is the most studied chronic sleep disorder. Although controversial, the severity of OSA is measured by the apnea–hypopnea index (AHI), which is the average number of apneas plus hypopneas per hour of sleep. Apnea is defined as cessation of airflow that lasts at least 10 seconds. As there has been considerable debate on what constitutes a hypopnea, a consensus conference defined a hypopnea as one of the following three: substantial reduction in airflow (>50%), moderate reduction in airflow (<50%) associated with desaturation (>3%), or moderate reduction in airflow with electroencephalographic evidence of arousal. During hypopneas and apneas, severe arterial hypoxemia and hypercapnia develop, until a brief arousal terminates the event and restores airway patency.