Department of Respiratory Medicine, Royal Brompton Hospital , London , United Kingdom.
Respiratory Research Unit, Bispebjerg Hospital , Copenhagen , Denmark.
J Appl Physiol (1985). 2018 Feb 1;124(2):356-363. doi: 10.1152/japplphysiol.00691.2017. Epub 2017 Nov 2.
Exercise-induced laryngeal obstruction (EILO), a phenomenon in which the larynx closes inappropriately during physical activity, is a prevalent cause of exertional dyspnea in young individuals. The physiological ventilatory impact of EILO and its relationship to dyspnea are poorly understood. The objective of this study was to evaluate exercise-related changes in laryngeal aperture on ventilation, pulmonary mechanics, and respiratory neural drive. We prospectively evaluated 12 subjects (6 with EILO and 6 healthy age- and gender-matched controls). Subjects underwent baseline spirometry and a symptom-limited incremental exercise test with simultaneous and synchronized recording of endoscopic video and gastric, esophageal, and transdiaphragmatic pressures, diaphragm electromyography, and respiratory airflow. The EILO and control groups had similar peak work rates and minute ventilation (V̇e) (work rate: 227 ± 35 vs. 237 ± 35 W; V̇e: 103 ± 20 vs. 98 ± 23 l/min; P > 0.05). At submaximal work rates (140-240 W), subjects with EILO demonstrated increased work of breathing ( P < 0.05) and respiratory neural drive ( P < 0.05), developing in close temporal association with onset of endoscopic evidence of laryngeal closure ( P < 0.05). Unexpectedly, a ventilatory increase ( P < 0.05), driven by augmented tidal volume ( P < 0.05), was seen in subjects with EILO before the onset of laryngeal closure; there were however no differences in dyspnea intensity between groups. Using simultaneous measurements of respiratory mechanics and diaphragm electromyography with endoscopic video, we demonstrate, for the first time, increased work of breathing and respiratory neural drive in association with the development of EILO. Future detailed investigations are now needed to understand the role of upper airway closure in causing exertional dyspnea and exercise limitation. NEW & NOTEWORTHY Exercise-induced laryngeal obstruction is a prevalent cause of exertional dyspnea in young individuals; yet, how laryngeal closure affects breathing is unknown. In this study we synchronized endoscopic video with respiratory physiological measurements, thus providing the first detailed commensurate assessment of respiratory mechanics and neural drive in relation to laryngeal closure. Laryngeal closure was associated with increased work of breathing and respiratory neural drive preceded by an augmented tidal volume and a rise in minute ventilation.
运动诱发的喉阻塞（EILO）是一种在体力活动中喉不适当关闭的现象，是年轻人运动性呼吸困难的常见原因。EILO 的生理通气影响及其与呼吸困难的关系尚不清楚。本研究旨在评估运动相关的喉口在通气、肺力学和呼吸神经驱动方面的变化。我们前瞻性地评估了 12 名受试者（6 名 EILO 和 6 名年龄和性别匹配的健康对照）。受试者进行了基础肺活量测定和症状限制递增运动试验，同时记录内镜视频和胃、食管和膈下压力、膈神经肌电图和呼吸气流。EILO 组和对照组的峰值工作率和分钟通气量（V̇e）相似（工作率：227 ± 35 与 237 ± 35 W；V̇e：103 ± 20 与 98 ± 23 l/min；P > 0.05）。在亚最大工作率（140-240 W）时，EILO 患者的呼吸功增加（P < 0.05）和呼吸神经驱动增加（P < 0.05），与内镜下喉关闭证据的出现密切相关（P < 0.05）。出乎意料的是，EILO 患者在喉关闭前出现通气增加（P < 0.05），这是由潮气量增加（P < 0.05）驱动的；然而，两组之间的呼吸困难强度没有差异。通过同时测量呼吸力学和膈肌肌电图与内镜视频，我们首次证明 EILO 发展时呼吸功和呼吸神经驱动增加。现在需要进行详细的进一步研究，以了解上气道关闭在导致运动性呼吸困难和运动受限中的作用。
运动诱发的喉阻塞是年轻人运动性呼吸困难的常见原因；然而，喉关闭如何影响呼吸尚不清楚。在这项研究中，我们将内镜视频与呼吸生理测量同步，从而首次对喉关闭与呼吸力学和神经驱动之间的关系进行了详细的一致评估。喉关闭与呼吸功增加和呼吸神经驱动增加有关，呼吸功增加和呼吸神经驱动增加先于潮气量增加和分钟通气量增加。
