Follow-up for patients with obstructive sleep apnea syndrome using a portable recording device.

A home screening device, LT-200, can record data on both breathing conditions and body positions during sleep for up to 3 consecutive days in patients with obstructive sleep apnea (OSAS). We investigated the usefulness of the LT-200 device for follow-up of OSAS. Eighteen patients (age 51.0 +/- 10.8 years, mean +/- SD) were enrolled in this study. Standard polysomnography (PSG) was performed on all patients. The number of apnea/hypopnea episodes per hour (apnea/hypopnea index: AHI), the total time that nocturnal oxygen saturation was < 90% (oxygen desaturation time: ODT), and the minimum oxygen saturation during sleep (lowest Spo2) were calculated. We used the LT-200 and PSG to evaluate any improvement in the data obtained after auto-continuous positive airway pressure (auto-CPAP) therapy. AHI was also measured using the LT-200 in three sleep positions to evaluate the efficacy of the lateral position. AHI, ODT, and lowest Spo2 values did not differ significantly between the PSG and LT-200 recordings on the control and therapy nights. The LT-200 recordings showed that AHI, ODT, and lowest Spo2 tended to be better on the second night of auto-CPAP therapy than on the first. AHI was significantly lower in the right and left lateral sleep positions than that in the supine position. Our findings suggest that since the LT-200 device provides important information about the severity of OSAS, the efficacy of auto-CPAP therapy, and body position under unattended conditions in the home. It may prove to be a useful tool for following up patients.