Department of Otolaryngology-Head and Neck Surgery, Chonnam National University Medical School and Chonnam National University Hospital, Gwangju, Republic of Korea.
Division of Sleep and Circadian Disorders, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts.
JAMA Otolaryngol Head Neck Surg. 2024 Nov 1;150(11):1012-1019. doi: 10.1001/jamaoto.2024.3319.
Mouth breathing is associated with increased airway resistance, pharyngeal collapsibility, and obstructive sleep apnea (OSA) severity. The common belief is that closing the mouth can mitigate the negative effects of mouth breathing during sleep. However, mouth breathing may serve as an essential route to bypassing obstruction along the nasal route (eg, the velopharynx).
To investigate the role of mouth breathing as an essential route in some patients with OSA and its association with upper airway anatomical factors.
DESIGN, SETTING, AND PARTICIPANTS: This nonrandomized clinical trial included participants diagnosed with OSA who underwent drug-induced sleep endoscopy. Patients were stratified into 3 quantiles based on oral-breathing level (quantile 1: oral airflow < 0.05 L/min; quantile 2: oral airflow 0.05-2.2 L/min; quantile 3: oral airflow > 2.2 L/min).
Closing the mouth during sleep during alternating breaths by applying pressure to the mentum until teeth are in occlusion.
The primary outcome was total inspiratory flow defined as the change in airflow in the transition from mouth relaxed to mouth closed, analyzed overall and by 3 oral-breathing quantiles. The association of velopharyngeal obstruction on the change in total inspiratory airflow was also investigated.
Of 66 enrolled patients with OSA, 12 were excluded due to insufficient baseline airflow. The analytic cohort consisted of 54 patients (39 [72%] male; median [IQR] age, 55 [46-64] years; apnea-hypopnea index, 26.9 [17.6-39.9] events/h; and body mass index calculated as weight in kilograms divided by height in meters squared, 28.9 [27.1-31.6]). Mouth closure increased total inspiratory flow by 27.8 percentage points overall (β, 1.0 [95% CI, 0.4-1.9] L/min). However, outcomes varied based on the degree of baseline oral breathing. No association was found for 10 patients with near-zero mouth breathing (0.9 [95% CI, -0.2 to 2.1] L/min). Airflow improved with mouth closure in 32 patients with moderate levels of mouth breathing (2.0 [95% CI, 1.3-2.7] L/min), whereas it worsened in patients with high levels of mouth breathing (-1.9 [95% CI, -3.1 to -0.6] L/min). Velopharyngeal obstruction was associated with increased mouth breathing (0.6 [95% CI, 0.1-3.0] L/min) and reduced airflow with mouth closure (-1.9 [95% CI, -3.1 to -0.7] L/min).
Although mouth closure increased inspiratory airflow in the overall cohort of this nonrandomized clinical trial, the outcomes were heterogeneous. In patients who breathe primarily through their mouth during sleep and have velopharyngeal obstruction, airflow worsens with mouth closure. Hence, personalized approaches to treating mouth breathing should be considered.
ClinicalTrials.gov Identifier: NCT06547658.
口呼吸与气道阻力增加、咽腔塌陷和阻塞性睡眠呼吸暂停（OSA）严重程度有关。人们普遍认为，闭嘴可以减轻睡眠中口呼吸的负面影响。然而，口呼吸可能是绕过鼻腔途径阻塞（例如，软腭）的重要途径。
研究口呼吸作为一些 OSA 患者的重要途径及其与上呼吸道解剖因素的关系。
设计、设置和参与者：这项非随机临床试验纳入了接受药物诱导睡眠内镜检查的 OSA 患者。患者根据口腔呼吸水平分为 3 个分位数（分位数 1：口腔气流<0.05 L/min；分位数 2：口腔气流 0.05-2.2 L/min；分位数 3：口腔气流>2.2 L/min）。
在交替呼吸时，通过对颏部施加压力使嘴闭合，直到牙齿咬合。
主要结果是总吸气流量，定义为从口松弛到口闭合的气流变化，总体和按 3 个口腔呼吸分位数进行分析。还研究了软腭阻塞对总吸气流量变化的影响。
在纳入的 66 例 OSA 患者中，有 12 例因基线气流不足而被排除。分析队列包括 54 例患者（39 [72%] 为男性；中位[IQR]年龄为 55 [46-64] 岁；呼吸暂停低通气指数为 26.9 [17.6-39.9] 次/小时；体重指数按千克体重除以米平方计算，为 28.9 [27.1-31.6]）。总的来说，口闭合使总吸气流量增加了 27.8 个百分点（β，1.0 [95% CI，0.4-1.9] L/min）。然而，结果因基线口腔呼吸程度而异。在 10 名几乎没有口腔呼吸的患者中，没有发现关联（0.9 [95% CI，-0.2 至 2.1] L/min）。在有中度口腔呼吸的 32 名患者中，口闭合后气流改善（2.0 [95% CI，1.3-2.7] L/min），而在有高度口腔呼吸的患者中，气流恶化（-1.9 [95% CI，-3.1 至-0.6] L/min）。软腭阻塞与增加的口腔呼吸（0.6 [95% CI，0.1-3.0] L/min）有关，与口闭合时的气流减少（-1.9 [95% CI，-3.1 至-0.7] L/min）有关。
尽管在这项非随机临床试验的总体队列中，口闭合增加了吸气气流，但结果存在异质性。在睡眠中主要通过口腔呼吸且有软腭阻塞的患者中，口闭合会使气流恶化。因此，应该考虑针对口呼吸的个体化治疗方法。
ClinicalTrials.gov 标识符：NCT06547658。
