Validation of Embletta portable diagnostic system for identifying patients with suspected obstructive sleep apnoea syndrome (OSAS)

Background and objectives: This study aimed to evaluate the diagnostic accuracy of Embletta portable diagnostic system (PDS, Medcare, Reykjavik, Iceland) for the screening of sleep apnoea in clinical practice. Methods: The Embletta PDS is a digital three-channel recording device that measures airflow through a nasal cannula connected to a pressure transducer, oxygen saturation plus both respiratory and abdominal movements via built-in effort and body position sensors. An AHI is determined based on recording time. Nocturnal polysomnography (Alice 4, Healthdyne, Atlanta, USA), with airflow measured by a nasal pressure transducer (PTAF2, Pro-Tech, Woodinville, WA, USA)) and Embletta PDS recordings, was performed simultaneously in consecutive patients with suspected OSA syndrome. The PSG recordings were analysed manually by a blinded investigator. Results: Ninety subjects were recruited and 10 failed Embletta PDS studies due to measurement failure. Among the remaining 80 subjects, 63 were males. The mean age (SD) was 51.4 (11.9) years old, BMI 27.1(4.2) kg/m(2), neck circumference 38.6 (3.6) cm and Epworth Sleepiness Score 9.7 (5.3). The AHI obtained by the Embletta PDS correlated closely with that obtained by PSG (Pearson correlation, r = 0.979, P < 0.001). Comparison of AHI based on the Embletta PDS against the PSG demonstrated high sensitivity at AHI >= 5/h (sensitivity 0.924 and specificity 0.857) and high specificity at AHI >= 20/h (sensitivity 0.853 and specificity 0.957). Conclusions: The Embletta PDS is a highly sensitive and specific screening device in quantifying AHI when compared against PSG in patients with suspected OSA syndrome.