Validation of a single channel airflow monitor for screening of sleep-disordered breathing

¹ Dept of Pulmonology, Fukuoka National Hospital, Fukuoka, Japan
² Dept of Public Health Medicine, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba, Japan
³ Dept of Internal Medicine, Tenri City Hospital, Tenri, Japan

^* To whom correspondence should be addressed. E-mail: nakano_h{at}palette.plala.or.jp.

	Abstract

Simple screening method for sleep-disordered breathing (SDB) is desirable for primary care practices. In the present study a simple monitor, which utilizes a new type flow sensor and a novel algorithm, was prospectively validated.

Two nights home recording with the monitor alone followed by in-laboratory recording with the monitor together with polysomnography were carried out in consecutive patients (n=100) suspected of SDB. A subjective sleep log was also recorded. The signal was analyzed using power-spectral analysis which yielded the respiratory disturbance index (flow-RDI).

There was no recording failure at home. The reproducibility of the flow-RDI between the two nights at home was high (intraclass correlation coefficient=0.92). The sensitivity and specificity of the in-laboratory flow-RDI to diagnose SDB were 0.96 and 0.82, 0.91 and 0.82, and 0.89 and 0.96, for AHI5, 15, and 30, respectively. The diagnostic ability in low severity subgroups (female, normal-weight, AHI<15) was almost comparable to that in the entire group. Excluding subjective waking time on the sleep log from the recording time had no significant effect on the flow-RDI.

The single channel monitor is considered feasible for ambulatory SDB monitoring because of its easy applicability, high reproducibility and relatively high agreement with the polysomnography results.