Upper airway resistance syndrome: The changing scenario

Abstract

Upper airway resistance syndrome (UARS) is a part of spectrum of sleep disordered breathing characterized by a partial collapse of the airway resulting in increased resistance to airflow. The resistance to airflow is typically subtle and does not result in apneic or hypopneic events. However, it does cause an increased negative intrathoracic pressure during inspiration which results in multiple sleep fragmentation. The diagnosis rests on polysomnographic documentation of > 10 electroencephalogram (EEG) arousals per hour of sleep correlated with episodes of reduced intrathoracic pressures measured by esophageal manometer in regular heavy snorers with daytime sleepiness. Oesophageal manometry being an invasive test, increasing number of non-invasive tests are developed to document the presence of UARS. In India these tests are not easily available hence high index of suspicion with polysomnographic correlation and use of available tests make the diagnosis possible.