KITE, University Health Network Toronto Rehabilitation Institute, Toronto, ON, Canada.
Institute of Biomedical Engineering, University of Toronto, Toronto, ON, Canada.
Ann Biomed Eng. 2024 Jun;52(6):1617-1624. doi: 10.1007/s10439-024-03475-3. Epub 2024 Mar 3.
Increased negative intrathoracic pressure that occurs during pharyngeal obstruction can increase thoracic fluid volume that may contribute to lower airway narrowing in individuals with obstructive sleep apnea (OSA) and asthma. Our previous study showed that fluid accumulation in the thorax induced by simulated OSA can increase total respiratory resistance. However, the effect of fluid shift on lower airway narrowing has not been investigated. To examine the effect of fluid accumulation in the thorax on the resistance of the lower airway. Non-asthma participants and individuals with (un)controlled asthma were recruited and underwent a single-day experiment. A catheter with six pressure sensors was inserted through the nose to continuously measure pressure at different sites of the airway, while a pneumotachograph was attached to a mouthpiece to record airflow. To simulate obstructive apneas, participants performed 25 Mueller maneuvers (MMs) while lying supine. Using the recordings of pressure sensor and airflow, total respiratory (R), lower respiratory components (R), and upper airway (R) resistances were calculated before and after MMs. Generalized estimation equation method was used to find the predictors of R among variables including age, sex, body mass index, and the effect of MMs and asthma. Eighteen participants were included. Performing MMs significantly increased R (2.23 ± 2.08 cmHO/L/s, p = 0.003) and R (1.52 ± 2.00 cmHO/L/s, p = 0.023) in participants with asthma, while only R was increased in non-asthma group (1.96 ± 1.73 cmHO/L/s, p = 0.039). We found the model with age, and the effect of MMs and asthma severity generated the highest correlation (R = 0.69, p < 0.001). We provide evidence that fluid accumulation in the thorax caused by excessive intrathoracic pressure increases R in both non-asthma and asthma groups. The changes in R were related to age, having asthma and the effect of simulated OSA. This can explain the interrelationship between OSA and asthma.
在咽阻塞期间发生的胸内负压增加可增加胸腔液体积，这可能导致阻塞性睡眠呼吸暂停（OSA）和哮喘患者的下气道变窄。我们之前的研究表明，模拟 OSA 引起的胸腔内液体积聚会增加总呼吸阻力。然而，胸腔内液移位对下气道狭窄的影响尚未得到研究。为了研究胸腔内液体积聚对下气道阻力的影响，我们招募了非哮喘参与者和（未）控制哮喘的个体，并进行了为期一天的实验。一根带有六个压力传感器的导管通过鼻子插入，以连续测量气道不同部位的压力，同时将呼吸流速仪连接到口件以记录气流。为了模拟阻塞性呼吸暂停，参与者仰卧位时进行 25 次 Mueller 动作（MM）。使用压力传感器和气流记录，在 MM 前后计算总呼吸（R）、下呼吸成分（R）和上气道（R）阻力。使用广义估计方程方法，根据年龄、性别、体重指数以及 MM 和哮喘的影响等变量，寻找 R 的预测因子。共纳入 18 名参与者。MM 显著增加了哮喘患者的 R（2.23±2.08 cmHO/L/s，p=0.003）和 R（1.52±2.00 cmHO/L/s，p=0.023），而非哮喘组仅 R 增加（1.96±1.73 cmHO/L/s，p=0.039）。我们发现，年龄、MM 和哮喘严重程度的影响的模型产生了最高的相关性（R=0.69，p<0.001）。我们提供的证据表明，胸内压力过大引起的胸腔内液体积聚增加了非哮喘和哮喘组的 R。R 的变化与年龄、哮喘和模拟 OSA 的影响有关。这可以解释 OSA 和哮喘之间的相互关系。
