Study objectives: To determine the diagnostic utility
of a nasal cannula/pressure transducer (NC), in comparison to
thermistor (TH), during routine, clinical nocturnal polysomnography
Design: We analyzed the respiratory arousal
index (RAI) using TH (RAI-TH) or NC (RAI-NC) in patients with suspected
sleep-disordered breathing (SDB).
disorders center of a university-affiliated teaching hospital.
Patients: Fifty consecutive, nonselected patients referred
for evaluation of suspected SDB.
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.