1 Sleep Medicine Center, Nanfang Hospital, Southern Medical University, Guangzhou, China; and.
2 Center for Sleep and Circadian Neurobiology, University of Pennsylvania, Philadelphia, Pennsylvania.
Am J Respir Crit Care Med. 2018 Dec 1;198(11):1435-1443. doi: 10.1164/rccm.201711-2171OC.
Obesity is a major risk factor for obstructive sleep apnea. Although greater dimensional changes in the upper airway during wake respiration have been noted in patients with apnea compared with control subjects, whether these differences remain in the presence of obesity is unknown.
To evaluate upper airway anatomic characteristics and airway compliance (distensibility) in obese subjects with obstructive sleep apnea compared with obese control subjects.
Dynamic magnetic resonance imaging was performed in 157 obese subjects with apnea and 46 obese control subjects during wakefulness in the midsagittal and three axial upper airway regions (retropalatal, retroglossal, epiglottal). Differences in measurements between subjects with apnea and control subjects, and correlations with apnea-hypopnea index among subjects with apnea, were examined.
Measurements included airway areas and linear dimensions. Subject-specific coefficients of variation were calculated to examine variability in airway size. Controlling for covariates, the retropalatal area during respiration was significantly smaller in subjects with apnea than control subjects, based on the average (P = 0.003), maximum (P = 0.004), and minimum (P = 0.001) airway area. Airway narrowing was observed in anteroposterior and lateral dimensions (adjusted P < 0.05). Results were similar in an age, sex, and body mass index-matched subsample. There were significant correlations between apnea-hypopnea index and dynamic measures of airway caliber in the retropalatal and retroglossal regions among subjects with apnea.
Upper airway caliber during respiration was significantly narrower in obese subjects with apnea than obese control subjects in the retropalatal region. These findings provide further evidence that retropalatal airway narrowing plays an important role in the pathogenesis of obstructive sleep apnea in obese subjects.
肥胖是阻塞性睡眠呼吸暂停的一个主要危险因素。尽管与对照组相比，患有呼吸暂停的患者在清醒时上气道的尺寸变化更大，但在肥胖的情况下，这些差异是否仍然存在尚不清楚。
评估肥胖伴阻塞性睡眠呼吸暂停患者与肥胖对照组患者的上气道解剖结构特征和气道顺应性（可扩张性）。
在清醒状态下，对 157 例肥胖伴呼吸暂停患者和 46 例肥胖对照组患者进行了动态磁共振成像，分别在中矢状面和三个轴位上气道区域（腭后、会厌后、会厌上）进行测量。分析了呼吸暂停患者与对照组之间测量值的差异，以及呼吸暂停患者中测量值与呼吸暂停低通气指数的相关性。
测量指标包括气道面积和线性尺寸。计算了气道尺寸的个体变异系数，以检查气道大小的变异性。控制协变量后，呼吸时的腭后气道面积在呼吸暂停患者中明显小于对照组（平均 P=0.003，最大 P=0.004，最小 P=0.001）。在前后和侧面尺寸上观察到气道狭窄（调整后 P<0.05）。在年龄、性别和体重指数匹配的亚组中，结果相似。在呼吸暂停患者中，呼吸暂停低通气指数与腭后和会厌后区域的气道口径动态测量之间存在显著相关性。
在肥胖伴呼吸暂停患者的腭后区域，呼吸时气道口径明显小于肥胖对照组。这些发现进一步证明了腭后气道狭窄在上气道阻塞性睡眠呼吸暂停患者发病机制中的重要作用。
