Abnormal airflow through the upper airway during sleep and chronic daytime sleepiness were first recognized as important and related clinical entities in 1965. Over the past 33 years, our ability to recognize, treat, and identify the morbidity associated with sleep-related breathing disorders has vastly improved. The boundaries of what is considered to be abnormal respiration during sleep have likewise grown because of more sensitive polysomnographic airflow and driving pressure measurements and a renewed understanding of what constitutes clinically significant EEG arousal. The evolution of our understanding of the upper airway resistance syndrome (UARS) is a prime example of this growth. In this review, we will consider this evolution, as well as our current understanding of the pathophysiology, clinical recognition, and treatment of UARS.
In 1993, the term “upper airway resistance syndrome” was first used by Guilleminault and colleagues to describe a subgroup of patients with conditions that were formerly diagnosed as idiopathic hypersomnia or CNS hypersomnia More info anti allergy medicine. These terms were used to describe excessive daytime sleepiness (EDS) without a cause that was clearly defined by a nocturnal polysomnogram (PSG) or the multiple sleep latency test (MSLT). The patients with UARS displayed repetitive increased upper airway resistance (IUAR) that was defined by increasingly negative inspiratory esophageal pressure (Pes) that occurred concomitant with decreased oronasal airflow in the absence of frank apnea or oxygen desaturation, These periods of IUAR were brief, typically lasting one to three breaths, and resulted in brief EEG arousals (from 2 to 14 s), followed immediately by decreased upper airway resistance.
UARS may be better understood by reviewing its historical development from the initial inclusion of these sleep-disordered patients as idiopathic hyper-somniacs, to their subsequent description as sleepy snorers, and to their current description as UARS patients. In 1982, Guilleminault and colleagues published the results of invasive polysomnography (including Pes measurements in 80% of those tested) on 25 pediatric patients who had been referred for snoring, EDS, and behavioral disturbances and 25 control subjects.