Validation of a low-load monitoring system based on millimeter-wave radar and pulse oximetry vs. polysomnography for obstructive sleep apnea diagnosis.

OBJECTIVES

To evaluate the clinical diagnostic efficiency of the low-load sleep monitor Tsingray Sleep Respiratory Monitoring System QSA600 (Tsingray QSA600) against type 1 polysomnography (PSG) for obstructive sleep apnea (OSA).

METHODS

This diagnostic study consecutively recruited 200 participants who underwent simultaneous overnight monitoring with both PSG and Tsingray QSA600 at the sleep center. The performance of Tsingray QSA600 was assessed against PSG considering 3 aspects: overnight sleep respiratory parameters, event-level analysis (apnea-hypopnea and oxygen desaturation), and sleep staging. Accuracy, sensitivity, specificity, intra-class correlation coefficient, Cohen's κ, and Bland-Altman analysis were evaluated.

RESULTS

The sensitivity and specificity for predicting the apnea-hypopnea index (AHI) in patients with mild, moderate, and severe OSA were 95.5%, 97.7%, and 96.5% and 77.6%, 86.8%, and 93.0%, respectively, with a mean absolute error of 3.573 events per hour. The intra-class correlation coefficient between the reference and predicted AHI was 0.965. The sensitivity and specificity were 83.4% and 94.3% for predicting individual apnea-hypopnea, and 71.4% and 92.0% for predicting oxygen desaturation events, respectively. The accuracy of predicting sleep stages (nonrapid eye movement, rapid eye movement, and wakefulness) was 80.3% (Cohen's κ: 0.614).

CONCLUSIONS

Tsingray QSA600 demonstrated significant practical application value owing to its good diagnostic efficacy, low-load, and accessible capability as a screening device for OSA and sleep tracking in patients with OSA. However, its limited accuracy in diagnosing mild OSA and interpreting sleep stages precludes replacing gold standard PSG.

TRIAL REGISTRATION: Validation study of a new type of sleep monitoring device for diagnosis of sleep-disordered breathing. www.chictr.org.cn (Identifier: ChiCTR2400093764).