UPPER AIRWAY PATENCY AND NOCTURNAL DESATURATION IN HABITUAL SNORING AND OBSTRUCTIVE SLEEP-APNEA - PATHOGENESIS OF SLEEP-RELATED BREATHING DISORDERS

Sixty patients, 53 men and 7 women: referred for excessive snoring or suspected sleep apneas syndrome were analyzed by polysomnography, Muel ler maneuver, cephalometric roentgenography, and pulmonary function te sting, to evaluate the contribution of static and dynamic upper airway obstruction in the pathogenesis of sleep-related breathing disorders and OSAS. Desaturation index and maximal desaturation were used in the analysis as indicators of severity of sleep-related breathing disorde rs. Body Mass Index, increased collapsibility at the base of the tongu e by the Mueller maneuver, increased distance between hyoid and mandib ular plane, and increased soft palate diameters by cephalometry as wel l as a decreased peak inspiratory flow by pulmonary function testing w ere found to be related to increased oxygen desaturation parameters. I n a multivariate analysis the significant obstruction parameters could explain only 37% of the variability of maximum desaturation and 31% o f the variability of desaturation index, 63 and 69%, respectively, mus t therefore be explained by other mechanisms. We conclude that instabi lity of respiratory and muscular control, possibly enhanced by sleep-p hase-related changes,is more important in the pathogenesis of sleep-re lated breathing disorders than pure anatomic narrowing of the airway.