[Analysis of sleep structure and related factors in children with severe obstructive sleep apnea-hypopnea syndrome]

Objective: To investigate the sleep structure and related factors in children with severe obstructive sleep apnea-hypopnea syndrome(OSAHS). Method: We summarized the characteristics of 250 children withsevere OSAHS diagnosed by polysomnography（PSG）in our hospital from January 1, 2017 to December 31, 2017. According to AHI, the patients were divided into three groups, 159 in group A with 20 < AHI≤0, 57 in group B with 40 < AHI≤60, and 34 in group C with AHI > 60. We collected the basic data, sleep parameters (sleep efficiency, latency, sleep stage, sleep index, etc.), preoperative arterial blood gas test results (awake and postsleep state), echocardiographic findings of the three groups. Statistical comparisons between groups were performed with SPSS19.0. Result: BMI, AHI, OAHI, LSaO₂ was significantly different with among the three groups (all P<0.01), and there was a linear correlation between BMI and AHI (r=0.251). There was significant differences in sleep efficiency (SE), sleep latency (SO), and rapid eye movement (REM) latency among the three groups. Compared with group A, the proportion of sleep in stage 1 increased by 38%, the proportion of sleep in stage 3+4 was decreased by 19%, and the proportion of REM was decreased by 14% in group C. There was no significant difference between group A and B. There was a significant linear correlation between AHI and ODI in NREM and REM, respectively (r¹=0.663, r₂=0.499, P< 0.001), and the ODI in REM (63.8±35.0) was significantly higher than that in NREM (29.7±36.0), accounting for 68% of the sleep. Sixty-five children had received preoperative arterial blood gas test (awake and post-sleep state). There was a significant negative correlation between AHI and SaO₂ after sleep (r=-0.444, P=0.000), and no significant correlation in awake state. Forty-four patients underwent preoperative echocardiographic examination. There was significant differences between group A and C in interventricular septum thickness, left ventricular diameter, and main pulmonary artery diameter (P<0.05). There was no significant difference between group A and B. There were no significant differences in aortic annulus diameter, left atrial diameter, left ventricular end diastolic dimension (LVEDD), ejection fraction(EF), and right ventricular anteroposterior diameter among the groups (P>0.05). Conclusion: Obesity is an important factor affecting the severity of OSAHS. As the severity of disease increased, the proportion of awakening time and stage 1 of sleep increased, but stage 3, 4 and REM decreased significantly. The SE, SO, and REM latency were significantly associated with the severity of OSAHS. The severity of hypoxemia is significantly related to AHI, and mainly occur in REM stage. Severe OSAHS is risk factor for cardiovascular complications.