Abstract
"Sleep related breathing disorders" is a term used to describe a wide spectrum of abnormalities of respiration during sleep, including obstructive sleep apnea (OSA), central sleep apnea disorders (CSAS) and sleep related hypoventilation disorders. In OSA, there is a cessation or a significant reduction in airflow in the presence of breathing effort due to the repetitive collapse of the upper airway during sleep compared to CSAS, in which the cessation of air flow is due to the absence of respiratory effort. Sleep related hypoventilation disorders are characterized by insufficient sleep related ventilation leading to abnormally elevated PaCO2 during sleep. This includes obesity hypoventilation syndrome (OHS), which is defined as PaCO2 > 45 mm Hg during wakefulness in patients with BMI > 30 kg/m(2) in the absence of other causes for elevated PaCO2. Obtaining a detailed history and performing a thorough clinical examination are essential in diagnosing these conditions. This should be followed by the necessary investigations, including polysomnography. Management of such patients involves patient education about the risk factors, natural history and consequences of these disorders as well as treating the underlying medical problems. The treatment is mainly directed toward improving ventilation during sleep with positive airway pressure (PAP) therapy, which provides pneumatic splinting of the upper airway with or without oxygen. There are other alternative therapeutic options, which should be tailored to patients' conditions, including the use of oral appliances (OA), surgery, hypoglossal nerve stimulation and pharmacological treatment.