[Clinical analyses of polysomnogram in snoring children]

To analyze the characteristics of sleep structure, heart rate and arousal index (ArI) in children with primary snoring (PS) and mild, moderate or severe obstructive sleep apnea hypopnea syndrome (OSAHS).

A total of 113 children with sleep disorders were enrolled from January 2010 to March 2012 at Affiliated Children's Hospital, Capital Institute of Pediatrics. All of them underwent polysomnogram (PSG) and the data were analyzed statistically by SPSS 19.0.

(1) No statistical difference existed in age, sleeping time or sleeping efficacy between PS and all OSAHS groups (all P > 0.05). (2) The proportion of stage I sleeping was 2.6% ± 1.4% in PS group, 5.4% ± 3.2% in mild OSAHS group, 4.7% ± 1.9% in moderate OSAHS group and 8.9% ± 4.0% in severe OSAHS group (F = 6.542, P = 0.000). The proportion of stage IV sleeping was 25.3% ± 5.6% in PS group, 32.4% ± 11.1% in mild OSAHS group, 30.6% ± 9.0% in moderate OSAHS group and 21.4% ± 10.8% in severe OSAHS group (F = 7.544, P = 0.000).The proportion of stage rapid eye movement (REM) sleeping was 21.1% ± 8.6% in PS group, 13.9% ± 4.0% in mild OSAHS group, 14.5% ± 4.9% in moderate OSAHS group and 12.3% ± 6.9% in severe OSAHS group (F = 11.204, P = 0.000).The proportion of stage II and III sleeping had no statistical difference among four groups. (3) The average heart rate in stage REM sleeping of four groups was (85 ± 11), (90 ± 14), (95 ± 10) and (101 ± 18) beats per minute(F = 6.452, P = 0.000) and (79 ± 10), (84 ± 14), (86 ± 7) and (93 ± 16) beats per minute in stage NREM sleeping(F = 5.369, P = 0.002). (4) In four groups, the difference of total count of spontaneous arousal, the spontaneous arousal count in stage REM and non-rapid eye movement (NREM) sleeping were all statistically significant (F = 56.379, 60.781, 44.061, all P = 0.000). And the difference of total count of respiratory arousal, the median of respiratory arousal count in stage REM and NREM sleeping were all statistically significant (F = 79.250, 36.137, 65.239, all P = 0.000).

Heart rate is affected more obviously in moderate-severe OSAHS children. As compared with PS counterparts, OSAHS children had a reduction of spontaneous arousal and an increase of respiratory arousal. But the occurrence of spontaneous arousal of OSAHS children does not decrease with the progress of OSAHS in either stage REM or stage NREM.