The role of single-channel nasal airflow pressure transducer in the diagnosis of OSA in the sleep laboratory.
BACKGROUND
Obstructive sleep apnea (OSA) is a common but underdiagnosed disorder. There is a need for validated simpler modalities such as single-channel monitors to assist diagnosis of OSA.


OBJECTIVE
To assess data sufficiency, agreement, and diagnostic accuracy of nasal airflow measured by a single-channel pressure transducer device (Flow Wizard, DiagnoseIT, Sydney, Australia) compared to attended full polysomnography (PSG) on the same night for OSA diagnosis.


METHODS
Cross-sectional study.


METHODS
Laboratory.


METHODS
Subjects with possible OSA referred to the sleep laboratory for PSG were eligible.


METHODS
Nasal airflow was measured by a pressure transducer in the laboratory concurrently with PSG.


RESULTS
Of 226 eligible subjects who consented, 221 (97.8%; 151 males, 70 females) completed the protocol. With nasal airflow measurement, 5.3% of subjects had insufficient data, compared with 2.2% on PSG. The mean difference between PSG AHI and NF RDI was -6.2 events/h with limits of agreement (+/- 2 standard deviation [SD]) of 17.0 events/hr. The accuracy of the Flow Wizard for diagnosing severe OSA (PSG AHI > 30) was very good (area under the ROC curve [AUC] 0.96; 95% confidence interval [CI] 0.92 to 0.99) and for diagnosing OSA (PSG AHI > 5) was good (AUC, 0.84; 95% CI, 0.77 to 0.90). There was no difference in the rate of data insufficiency and accuracy between males and females.


CONCLUSIONS
Nasal flow measured by a nasal pressure transducer has a low rate of data insufficiency, good agreement, and high accuracy compared to PSG for diagnosing OSA in the monitored sleep laboratory setting.
Rofail
Lydia Makarie
LM
National Health Medical Research Council Centre for Clinical Research Excellence in Respiratory and Sleep Medicine, Australia. lydiamr@woolcock.org.au
Wong
Keith K H
KK
Unger
Gunnar
G
Marks
Guy B
GB
Grunstein
Ronald R
RR
D000328:Adult; D003362:Cost-Benefit Analysis; D003430:Cross-Sectional Studies; D004867:Equipment Design; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017286:Polysomnography / Q000191:economics / Q000295:instrumentation*; D025363:Rhinomanometry / Q000191:economics / Q000295:instrumentation*; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted / Q000295:instrumentation*; D020181:Sleep Apnea, Obstructive / Q000175:diagnosis* / Q000191:economics; D014160:Transducers, Pressure