Use of a screening tool for detection of sleep-disordered breathing

Sleep apnoea, whether obstructive or central, is usually diagnosed by polysomnography. A simpler tool for screening high risk populations may be of value.

We compared a portable device using nasal pressure cannulae and a high-sensitivity pressure sensor (the ApneaLink) with our standard polysomnography technique for diagnosing sleep apnoea (using the Embletta device), in 67 patients being investigated for possible sleep apnoea. The patients' average age was 52.6, 79 per cent were male, the mean body mass index was 32.3, and the mean Epworth sleepiness score was 13.0.

Twenty-five patients (45 per cent) were identified as having an apnoea-hypopnoea index of >15, as measured by the Embletta. The mean (standard deviation) apnoea-hypopnoea index was 21.5 +/- 23.0 as measured by the Embletta and 24.3 +/- 26.2 as measured by the ApneaLink. The sensitivity of the ApneaLink for an apnoea-hypopnoea index cut-off point of 15 was 92 per cent and the specificity was 96.7 per cent. The negative predictive value of the ApneaLink for an apnoea-hypopnoea index of < or = 15 was 94 per cent.

The ApneaLink is a useful tool for screening patients thought to have possible sleep apnoea, and for selecting patients for definitive diagnostic testing.