History of Sleep-Disordered Breathing
Sleep-disordered breathing (SDB) is an extremely common medical disorder associated with important morbidity. Recognition of its relevance in medicine is relatively recent, although clinical reports of SDB were first made in the 19th century.1 Likely influenced by such observations, descriptions of an entity constituting obesity and extreme somnolence were highlighted in the character narratives of the “fat boy” in Charles Dickens’ series, Posthumous Papers of the Pickwick Club, first published in 1837.2 Dickens described Joe, the fat boy, as a loud snorer who was obese and excessively somnolent—the classical description of Pickwickian syndrome. Sir William Osler in 1918 was credited with first linking the relationship between obesity and Pickwickian syndrome.3 In the mid-20th century, further work led to the association of Pickwickian syndrome with alveolar hypoventilation by Burwell et al. in 1956, and periodic cessation of respiration by Drachman and Gumnit in 1962.4,5
Over the last 40 years, we have begun to understand the pathogenesis of sleep apnea and have developed effective diagnostic and treatment modalities for this common disorder. Gastaut et al.6 in 1965 showed that cessation of respiration was due to obstruction of the upper airway, and obstructive sleep apnea (OSA) was recognized. In 1972, a conference organized by Lugaresi and his Bologna (Italy) group entitled “Hypersomnia and Periodic Breathing,” served as a springboard for the growth of interest and research in SDB.7 Guilleminault et al.8 coined the terms sleep apnea syndrome and obstructive sleep apnea syndrome (OSAS) in 1976 to underscore that airway obstruction during sleep was not restricted to obese subjects.
As the understanding of the etiology of OSA increased, treatment options began to emerge. In 1969, a case report describing treatment of OSA in a patient with tracheostomy was published.9 The first reports demonstrating reversal of OSA with positive airway pressure (PAP) did not occur until more than 10 years later.10,11 The role of weight loss and its shortcomings in resolution of OSA was noted by Fishman in 1972.12
Adult SDB is present when repetitive apneas (episodes of breathing cessation) and hypopneas (episodes of decrement in airflow) occur during sleep, usually associated with sleep fragmentation, arousals, and reductions in oxygen saturation. Apneas are generally defined as an episode of breathing cessation lasting at least 10 seconds in duration, and can be classified as obstructive (in which there is no airflow despite continued respiratory effort), central (no airflow and no respiratory effort), or mixed (events initially appear central in origin, with respiratory effort occurring during the latter portion of the same episode). Hypopneas are SDB events during which decrements in airflow are observed and can also be obstructive or central in origin. In practice, hypopnea definitions vary substantially according to the degree of airflow limitation expected, the magnitude of oxygen desaturation needed, and ...