Detection of upper airway resistance syndrome using a nasal cannula/pressure transducer.

STUDY OBJECTIVES To determine the diagnostic utility of a nasal cannula/pressure transducer (NC), in comparison to thermistor (TH), during routine, clinical nocturnal polysomnography (NPSG). DESIGN We analyzed the respiratory arousal index (RAI) using TH (RAI-TH) or NC (RAI-NC) in patients with suspected sleep-disordered breathing (SDB). SETTING Sleep disorders center of a university-affiliated teaching hospital. PATIENTS Fifty consecutive, nonselected patients referred for evaluation of suspected SDB. MEASUREMENTS AND RESULTS Twenty patients were found to have obstructive sleep apnea/hypopnea syndrome (OSA), 25 had upper airway resistance syndrome (UARS), and 5 had primary snoring (PS). Mean RAI-NC was greater than the mean RAI-TH by 25%, 302%, and 500% in OSA, UARS, and PS, respectively. RAI-NC was >/= 14 (mean, 25.2) in UARS and < 14 (mean, 9) in PS. Mean RAI-TH was 8.4 in UARS and 1.8 in PS, with significant overlap between the two groups. CONCLUSIONS NC is more sensitive than TH in detecting respiratory events during NPSG and may represent a simple, objective means to identify UARS among patients with a range of SDB.