Usefulness of arousal for the diagnosis of sleep breathing disorder

We hypothesize that breathing disorder related arousal index (B-ArI) can differentiate sleep breathing disorder from simple snorer when apnea hypopnea index (AHI) is low. We studied 54 patients using polysomnography. Breathing disorder related arousal (B-Ar) was defined as arousal accompanied by apnea, hypopnea, desaturation or snort. Mean AHI was 44.2+/-34.0/h, and B-ArI correlated significantly with AHI, desaturation index, percentage total sleep time with SpO2 below 90%. Breathing disorder related arousal index was greater than AHI when AHI was below 20. In 11/54 patients, AHI was below 10, and B-ArI more than 10. Nasal continuous positive airway pressure was applied to six patients and showed reduced B-ArI. Breathing disorder related arousal index may be one of the useful indices for the diagnosis of sleep breathing disorder when AHI is less than 10.