Furthermore, because all four of the patients with UARS had > 30 flow-limited events/h (a flow-limited breathing event consisted of two or more consecutive, flow-limited breaths), they could be separated from the asymptomatic subjects in the analysis. This is a promising noninvasive way to diagnose UARS. Further study is warranted, however, because of the small number of patients and because one of them had breaths with flattened flow contours as a result of a flattened driving pressure contour (as assessed by Pes), rather than as a result of IUAR.
Therefore, caution must be used in interpreting either quantitative flow data or driving pressure Pes data alone. Because they rely on changes in temperature as a surrogate of airflow, thermistors or thermocouples correlate poorly with quantitative flow measurements, resulting in an erroneous assessment of IUAR. ventolin inhaler
Clinical Features Signs and Symptoms
By definition, UARS patients have daytime sleepiness or fatigue. The original 1982 description concerned children and reported frequent snoring, restlessness during sleep, and sweating. Other characteristics more specific to children included a change in appetite, poor performance in school, and problems with behavior. Initial studies in adults included only men; it was later recognized that the syndrome was also present in women, with a roughly equal gender distribution. Contrary to what is seen in OSAS patients, UARS patients are typically nono-bese, with a mean BMI of < 25 kg/m2. They are also frequently younger than OSAS patients; the 1993 study showed a mean age of 37.5 years. Additionally, all 15 subjects in this investigation had mildly abnormal upper airway anatomy (most commonly retrolingual narrowing) as determined by cephalometry. In the same study, it was also recognized that not all UARS patients snored, as was previously thought; only 10 of 15 patients were regular snorers, and 2 of 15 patients never snored. Furthermore, snoring may be absent after palatal surgery, even though UARS may be present. Low soft palates, long uvulas, increased overbites, and high, narrow hard palates have also been described in this syndrome; these features in combination with EDS, hypertension, and snoring may render these patients clinically indistinguishable from OSAS patients in the absence of PSG.