Compressed tracheal sound analysis in screening of sleep-disordered breathing.
OBJECTIVE
To evaluate the suitability of compressed tracheal sound signal for screening sleep-disordered breathing.


METHODS
Thirty-three consecutive patients underwent a polysomnography with a tracheal sound analysis. Nineteen patients were healthy except for the sleep complaint, 9 were hypertonic and 3 were hypertonic and had elevated cholesterol. Minimum and maximum values of each consecutive, non-overlapping segment of 15s of original sound data were extracted. All these compressed tracheal sound traces were divided into plain, thin and thick signal periods. Also pure, 10-min episodes of plain, thin and thick tracheal sound periods were selected and the nasal pressure flow shapes during these pure sound periods were examined.


RESULTS
There was a significant positive correlation between the total nocturnal amount of thick periods and AHI. Apneas and hypopneas were most common during the 10-min episodes of thick sound periods. The proportion of round (normal, non-flattened) inspiratory flow shape was highest during the pure plain periods.


CONCLUSIONS
Breathing consisting of apneas and hypopneas can quite reliably be visualised with compressed tracheal sound analysis. The other interesting outcome of the study is that even prolonged flow limitation might be revealed with the method.


CONCLUSIONS
Compressed tracheal sound analysis might provide a promising screening method for obstructive apneas and hypopneas.
Rauhala
Esa
E
Department of Clinical Neurophysiology, Medical Imaging Centre, Pirkanmaa Hospital District, Tampere, Finland. esa.rauhala@satshp.fi
Hasan
Joel
J
Kulkas
Antti
A
Saastamoinen
Antti
A
Huupponen
Eero
E
Cameron
Frank
F
Himanen
Sari-Leena
SL
D000293:Adolescent; D000328:Adult; D000368:Aged; D004569:Electroencephalography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017286:Polysomnography / Q000379:methods; D012119:Respiration; D012135:Respiratory Sounds / Q000503:physiopathology*; D012893:Sleep Wake Disorders / Q000473:pathology* / Q000503:physiopathology*; D018709:Statistics, Nonparametric; D014132:Trachea / Q000503:physiopathology*; D014353:Trypanosomiasis, African