[Effects of sleeping body posture on sleeping structure and respiratory events in patients with OSAHS]

To observe the effects of sleeping body posture on sleeping structure and respiratory events in patients with OSAHS.

We assessed the sleeping body position, the sleeping structure, position specific AHI and the Epworth Sleepiness Scale (ESS) in a total of 80 patients with Positional OSAHS. The patients were grouped according to AHI: mild OSAHS (5 < or = AHI <15), moderate (15 < or = AHI < 30) and severe (AHI > or = 30). The polysomnography data and clinical characteristics were compared between each group.

The severe OSAHS group, when compared with the mild and the moderate ones, had a significant different in REM%, NREM%, NREM LSaO2, RDI, S-AHI and L-AHI due to posture (P < 0.05). The severe and the mild OSAHS groups had significant different in MSaO2, LSaO2 due to posture (P < 0.05). The moderate and the mild OSAHS group had significant different in LSaO2, REM LSaO2 and RDI (P < 0.05). In all mild, moderate and severe groups, the LT% were higher than ST%, but the difference was not significant (P > 0.05). For mild-to-moderate groups, there was no correlation between the ESS and the AHI for any position different (P > 0.05). For severe group, the ESS was significantly correlated with L-AHI (r = 0.551; P < 0.01); the REM L-AHI and NREM L-AHI was also significantly correlated with ESS of severe group (r were 0.516 and 0.528, P < 0.01).

The L-AHI, NREM L-AHI, REM L-AHI and NREM LSaO2 were considered to monitor the stability of OS-AHS, while REM LSaO2 were consider to clarify the severity of OSAHS.