EVALUATION OF AN AMBULATORY DEVICE, CID-102, IN THE DIAGNOSIS OF OBSTRUCTIVE SLEEP-APNEA SYNDROME

Diagnosis of obstructive sleep apnoea syndrome (OSAS) is usually perfo rmed during overnight polysomnography in the sleep laboratory. In an a ttempt to simplify the diagnostic strategy, we compared an ambulatory device, CID 102, with polysomnography during the same night in the lab oratory in 50 consecutive patients referred for polysomnography, The C ID 102 device monitors oxygen saturation, heart rate, body position an d tracheal breath sounds, An acoustic pressure sensor is placed on the suprasternal notch, Signals coming from this sensor are amplified and analysed in three different channels, according to their frequency an d energy, CID respiratory disturbance index is defined as the number, per hour of analysis time, of apnoeas lasting more than 10s plus episo des of desaturation;by 4% or more associated with pauses lasting from 7-10s or snores, The polysomnographic data were recorded on paper (Ree ga 2000, Alvar) and analysed manually. Polysomnographic apnoea-hypopno ea index (AHIp) was defined as the number of apnoeas plus hypopnoeas p er hour of sleep, The sensitivity, specificity, positive predictive va lue and negative predictive value of various CID respiratory disturban ce index (greater than or equal to 5, greater than or equal to 10, gre ater than or equal to 15 and greater than or equal to 20 per hour) in diagnosing obstructive sleep apnoea syndrome were determined, When OSA S was diagnosed as AHIp greater than or equal to 15, sensitivity and s pecificity of a CID respiratory disturbance index greater than or equa l to 5 were 73 and 62%, respectively, Positive predictive value of CID respiratory disturbance index greater than or equal to 10 for AHIp gr eater than or equal to 10 was 94%, CID 102 false negative patients had only hypopnoeas without any desaturation, These results suggest that CID 102 may be helpful in the detection of severe respiratory disturba nces during sleep but does not have the diagnostic value of polysomnog raphy.