Tracheal sound analysis – a new technology for detection of sleep disordered breathing
Purpose : This study aimed to assess a portable polygraphic device (CID102L, Cidelec) using an advanced tracheal sound analysis (PneaVox, Cidelec) to diagnose sleep disordered breathing (SDB). The portable device was compared with polysomnography (EMBLA, Embla Inc.) to evaluate the reliability of tracheal sounds.
Purpose : Overnight CID102L and EMBLA measurements were carried out simultaneously in 18 subjects suffering from SDB. For reference apneas and hypopneas were detected by EMBLA airflow, thoracical and abdominal chest movements and oxygen saturation measurements. Snoring from the CID102L was perceived from tracheal sounds whereas snoring in EMBLA was detected from a nasal pressure sensor. The CID102L used a tracheal sensor to detect apneas and to characterize them as obstructive, central or mixed, according to an additional signal: the suprasternal pressure, extracted from the tracheal sounds.
Results : Mean age was 51.8±8.6 years and BMI was 29.7±5.5 kg/m2. Considering the time in bed as a common value for analysis, EMBLA apnea/hypopnea index (AHI) was 29.8±17.9 /h correlated significantly to CID102L AHI with 37.7±19.5 /h (r=0.83 p<0.0001). Mean detected snoring time with EMBLA was 56.8±68 min compared to 158.1±113.5 min with CID102L.
Conclusions and perspectivest : The CID102L AHI correlates very well with EMBLA findings. The fact that snoring time was considerably high in CID102L could be due to the fact that snoring in CID102L is directly detected through the throat instead from the nose as in EMBLA. In conclusion by using tracheal sound analysis an additional diagnostic value in the detection of upper airway obstruction could be expected.