Study of the relationship between arousal parameters and daytime sleepiness in patients with obstructive sleep apnea syndrome

Abstract

To explore the effect of arousal parameters on excessive daytime sleepiness(EDS) in patients with obstructive sleep apnea syndrome(OSAS). A total of 205 patients who underwent polysomnography (PSG) from June 2012 to September 2013 in our hospital were enrolled. They were divided into 3 groups:85 patients in the OSAS sleepiness group (AHI ≥ 5/h, ESS ≥ 9), 86 patients in the OSAS non-sleepiness group (AHI ≥ 5/h, ESS<9), and 34 healthy subjects in the control group (AHI<5 times/h, ESS<9). Patient characteristics and PSG parameters of the 3 groups were analyzed. The difference of age, BMI, ESS, N1+ N2%, N3%, AHI, oxygen desaturation index (ODI), mean oxygen saturation (MSaO₂), lowest oxygen saturation (LSaO₂), oxygen below 90% of the time (T90%), total arousal index (ARtotI), respiratory arousal index/ARtotI (RAI/ARtotI), spontaneous arousal index/ARtotI (SAI/ARtotI), sleep pressure score (SPS) were statistically different among the 3 groups (P < 0.05). But except for REM% [(15 ± 5)%, (16 ± 6)%, (17 ± 7)%, P > 0.05], the difference of age and BMI between OSAS sleepiness group and OSAS non-sleepiness group were not significant (P > 0.016 7), but the difference of other indices between any 2 groups were significant (P < 0.016 7). ARtotI and SPS were positively correlated with ESS (r = 0.383 and 0.244, P < 0.001). Logistic regression analysis showed that only awakening and SPS were the risk factors for OSAS [OR = 1.070 (95% CI: 1.038 - 1.102) and 0.158 (95% CI: 0.026 - 0.984), respectively]. Arousal at night is closely associated with EDS in OSAS. ARtotI and SPS can be evaluated as an objective indicator of EDS in OSAS patients.