title: How important is the differentiation between apnea and hypopnea?
abstract: Apnea and hypopnea during sleep are often viewed as different expressions of the same sleep-related breathing disorder. In our point of view, both symptoms are two different entities which can occur in the same patient. We discuss the hypothesis that sleep apnea is a disorder associated with recurrent arousals and chronic activation of the sympathetic nervous system, leading to daytime sleepiness and disturbances in the autonomic system. Hypoventilation results from reduced alveolar ventilation and is associated with hypercapnia. In rare cases it is caused by genuine disorders of the breathing center, like Odine's curse. In most cases, hypoventilation is secondary to an underlying disease and a strategy of the body, to avoid respiratory muscle failure. Treatment trials of hypoventilation of the respiratory muscles by stimulating the breathing center failed to be beneficial. However, unloading treatment with long-term oxygen and/or home mechanical ventilation improves arterial blood gases, physical activity and prognosis.
authors.affiliation: Krankenhaus Kloster Grafschaft, Zentrum für Pneumologie, Beatmungs- und Schlafmedizin, Schmallenberg, Deutschland.
authors.forename: D
authors.initials: D
authors.lastname: Köhler
authors.forename: B
authors.initials: B
authors.lastname: Schönhofer
mesh_terms: D001143:Arousal / Q000502:physiology; D001341:Autonomic Nervous System / Q000503:physiopathology; D006801:Humans; D006935:Hypercapnia / Q000209:etiology; D007040:Hypoventilation / Q000209:etiology / Q000503:physiopathology; D009043:Motor Activity / Q000502:physiology; D010100:Oxygen / Q000097:blood; D010102:Oxygen Inhalation Therapy; D011379:Prognosis; D011650:Pulmonary Alveoli / Q000503:physiopathology; D012119:Respiration / Q000502:physiology; D012121:Respiration, Artificial; D012132:Respiratory Muscles / Q000503:physiopathology; D012891:Sleep Apnea Syndromes / Q000145:classification* / Q000150:complications / Q000503:physiopathology / Q000628:therapy; D012894:Sleep Stages / Q000502:physiology; D013564:Sympathetic Nervous System / Q000503:physiopathology
chemical_list: D010100:Oxygen