.' -., Sleep, 3(3/4):225 - 226 © 1980 Raven Press, New York Some Cineradiographic Aspects of Snoring and Obstructive Apneas F. Cirignotta and E. Lugaresi Institute of Clinical Neurology, University of Bologna, Italy On the basis of our previously reported cineradiographic data in obstructive sleep apnea, we concluded that the obstruction was usually caused by a valve mechanism at the Ie vel of the oropharynx (Lugaresi et al., 1979). In 1 of 8 patients examined, we identified a different, rare mechanism, This patient had a mixed type of apnea during the cineradiographic monitoring, During the diaphragmatic arrest, the epiglottis fell backward, completely obstructing the glottis during the subsequent inspiratory effort. We also observed that the abnormal subatmospheric intrathoracic pressures developed during obstructive apneas (with values reaching 100-150 cm H 2 0) have important consequences for cardiac function. The cineradiographic monitoring showed that during episodes of obstructive apnea, the cardiac shadow was greatly enlarged. Cardiac hypertrophy and cardiac failure are observed commonly in patients with obstructive sleep apnea, and they are usually explained on the basis of chronic alveolar hypoventilation. However, our cineradiographic evidence suggests the possibility that the cardiac hypertrophy and failure are due in part to the profound modifications in cardiac function which result from these large swings in SUbatmospheric intrathoracic pressures. Another piece of cineradiographic evidence we have not yet reported concerns the lowering of the larynx during inspiration in heavy snorers, In these subjects the increase of the negative endothoracic pressure that occurs during inspiration (with negative values reaching 50 em H 2 0) causes a lowering of the whole laryngo-tracheo-bronchial complex, with a consequent lengthening and narrowing of the oropharyngeal tract. An isthmus is thus formed, where the airflow becomes faster, and the inspiratory collapse due to the "Venturi effect" becomes more pronounced, favoring further narrowing, until total obstruction is reached (Figs. 1 and 2). This phenomenon occurs when the patient is asleep and not while he is awake, because, as shown by Remmers et al. (1976) and Sauerland and Harper (1976), it is only during sleep that the oropharyngeal muscles are markedly hypotonic. The narrowing of the upper respiratory tract caused by the stretching of the oropharynx might explain why the obstruction always occurs in the oropharynx, irrespective of the site of anatomical stenosis, This is because the oropharyngeal walls are the only soft and elastic segment of the upper respiratory tract. Accepted for publication September 1980. Address correspondence and reprint requests to Dr. Cirignotta at Clinica Neurologica dell'Uni- versita di Bologna, Via U. Foscolo 7, 40123 Bologna, Italy. 225 Downloaded from https://academic.oup.com/sleep/article-abstract/3/3-4/225/2750233 by guest on 10 June 2020