[Effects of sleep body posture on subjective sleepiness in patients with OSAHS]

Objective:To observe the effects of sleep body posture on subjective sleepiness in patients with OSAHS.Method: We assessed the sleeping body position, the sleep structure, position specific AHI and the Epworth Sleepiness Scale (ESS) in a total of 90 patients with OSAHS. The patients were grouped according to AHI: mild OSAHS (5≤AHI<15), moderate (15≤AHI<30) and severe (AHI≥30). The polysomnography data and clinical characteristics were compared between each group.Result: There was statistically significant difference in arousal index，MinSpO2，REM% and NREM% among three groups (F value was 12.10,43.67,15.81,13.17，respectively，P<0.05). Compared with supine，the severe OSAHS group had significantly bigger changes in MinSpO2， REM% and NREM%（t value was 3.02,2.41,2.90，respectively，P<0.05）. For mild-to-moderate groups，there was no correlation between the ESS and the AHI at any position（P>0.05）. For severe group，the ESS was significantly correlated with L-AHI（r=0.454，P<0.01)；the REM L-AHI and NREM L-AHI was also significantly correlated with ESS of severe group (r=0.522 and 0.425，P<0.01). Conclusion:The sleep body posture had significant effects on sleep structure and respiratory events in severe OSAHS group. The L-AHI was found to have a closer association with daytime sleepiness in severe OSAHS than other groups.