Sleep Related Breathing Disorders
Disordered respiration during sleep may lead to sleep fragmentation, daytime sleepiness, and significant health problems.
Obstructive Sleep Apnea
Obstructive sleep apnea is characterized by repetitive partial (i.e., hypopnea) or total (i.e., apnea) obstruction of the upper airway with subsequent increased ventilatory effort (e.g., snoring, gasping, choking) resulting in cortical arousals and/or oxygen desaturations. The fragmentation of sleep may lead to excessive daytime sleepiness as well as insomnia. If untreated, obstructive sleep apnea may lead to hypertension, stroke, and cardiovascular morbidity. Obstructive sleep apnea should be considered in those with excess body weight but also in thin individuals or children with abnormal anatomical features.
Central Sleep Apnea
Central sleep apnea is characterized by cessation of respiration due to repetitive lapses in ventilatory effort resulting in sleep fragmentation. Unlike obstructive sleep apnea, patients with central sleep apnea commonly complain of awakening during sleep and insomnia, but less commonly of daytime sleepiness. Central sleep apnea is often idiopathic (i.e., primary central sleep apnea), but can be triggered by drug use (i.e., opioids) or dysfunctions in the cardiac, renal, or central nervous systems. Cheyne Strokes Breathing Pattern is a specific central sleep apnea syndrome in which the recurring apneic episodes involve a gradual waxing and waning pattern. High-altitude periodic breathing is a specific central sleep apnea syndrome manifest by headaches, loss of appetite, nausea, dizziness, and insomnia which become present after a rapid ascent (i.e., greater than 300 m/day to an altitude above 4000 m.
Hypoventilation syndromes are characterized by an elevation of the arterial carbon dioxide tension to above 45 mm Hg due to an imbalance between the metabolic production, circulation, and elimination of carbon dioxide through exhaled gas. Sleep related hypoventilation syndromes most commonly stem from pulmonary parenchymal or vascular pathologies, lower airway obstructions, or neuromuscular and chest wall disorders and are associated with insomnia and daytime. Hypoxemia disorders are associated with a consistent and sustained reduction in oxygen saturation throughout the nocturnal period. Chronic lung diseases such as chronic obstructive pulmonary disease, cystic fibrosis, and asthma can lead to the development of sleep related hypoventilation/hypoxemia syndrome and other problems that can disrupt sleep.