Canadian Health and Care Mall: Resistance Syndrome

excessive daytime sleepinessUpper airway resistance syndrome (UARS) is a recently described form of sleep-disordered breathing that may result in excessive daytime sleepiness (EDS). UARS is defined by repetitive increases in upper airway resistance (IUAR) associated with brief EEG arousals. The diagnosis requires demonstration of IUAR in a crescendo pattern of negative inspiratory pressures on esophageal manometry. We used a negative inspiratory pressure of < — 12 cm H2O in scoring these studies. The resulting arousals are followed by normalization of Pes. However, esophageal manometry is not commonly employed, making UARS difficult to diagnose definitively. Clinicians often make the diagnosis presumptively based on the presence of crescendo snoring associated with respiratory effort-related arousals (RERAs). Limited use of esophageal manometry may underdiagnose UARS and may lead to misclassification of a patient’s hypersomnolence. This misdiagnosis may, in turn, result in the inappropriate use of stimulants as a potential treatment of EDS. These therapies may be ineffective or may mask the underlying sleep disorder.

Although difficult to diagnose, UARS is suggested by EDS associated with snoring in patients who do not demonstrate apneic or hypopneic respiratory events on polysomnography. However, patients may manifest sleep-disordered arousals consistent with UARS even in the absence of snoring, which we define as silent UARS (SUARS). The purpose of this article is to report the occurrence and prevalence of SUARS in our population.

We retrospectively reviewed all patients who underwent polysomnography for the evaluation of EDS at our sleep disorders center during 2000. Our center serves active duty military personnel, military retirees, and their dependent family members. A lot of diseases may appear because of genetic factor. But there are gained disorders. To know more about diseases, treatment and preparations you may follow the link

Respiratory disturbance indexAll patients were studied by attended overnight polysomnography in our sleep laboratory using a 16-channel montage (SensorMedics a Somnostar System; SensorMedics; Yorba Linda, CA). Polysomnography consisted of continuous recordings of central and occipital EEGs, bilateral electro-oculograms, submental and bilateral tibial electromyograms, and ECG. Nasal and oral airflow was measured by thermistor or pressure transducer. Tracheal sounds were monitored using an acoustic microphone. Thoracic and abdominal excursions were measured using inductance plethysmography. Continuous oxygen saturation was assessed using noninvasive pulse oximetry. Body positioning was verified by infrared video recording. The study lasted 6 to 8 h and terminated following final wakening. Polysomnographies were scored in 30-s epochs following Rechtschaffen and Kales criteria for sleep staging. Arousals were defined as a change in EEG activity from a slower background frequency for > 1 s.

Hypersomnolent patients with a respiratory disturbance index (RDI) [apnea/hypopnea] <5/h and a total arousal index (TAI) > 10/h were routinely reevaluated by polysomnography with esophageal manometry in an attempt to diagnose UARS. Hypersomnolence was defined as a score > 10 on an Epworth sleepiness scale (ESS). Esophageal manometry utilized a multiport Gaeltec catheter (Gaeltec Ltd; Hackensack, NJ). RERAs were scored when IUAR was followed by an EEG arousal. IUAR was established by the development of a negative inspiratory pressure of 5/h and an RDI < 5/h.

Data were analyzed using repeated measures with analysis of variance for the crossover design. The two groups, SUARS and UARS, were compared and analyzed using independent-sample t test, and the level of significance was set at p < 0.05. Statistical analysis was carried out using software (SPSS for Windows version 11.0; SPSS; Chicago, IL).

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