Inspiratory dyspnea - Inspiratory dyspnea

…Dyspnea generally occurs during both inspiration and expiration. However, if there is a stenosis in the upper airways, such as the larynx or cervical trachea, the airway pressure becomes negative compared to the pressure of the surrounding tissues during inspiration, intensifying the stenosis, but the airway pressure becomes positive compared to the surroundings during expiration, reducing the stenosis, and dyspnea occurs during inspiration (inspiratory dyspnea). In contrast, if there is a stenosis in the trachea and bronchi within the thorax, the pressure relationship is exactly the opposite to that in the upper airways, and the stenosis increases during expiration, resulting in expiratory dyspnea. …

*Some of the terminology that refers to "inspiratory dyspnea" is listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…呼吸困難は一般に，吸気時，呼気時ともに存在する。しかし，喉頭，頸部気管などの上気道に狭窄があると，気道内圧は吸気時に周囲の組織の圧より陰圧になるため狭窄が強められるが，呼気時には気道内圧が周囲より陽圧になるため狭窄は軽減され，呼吸困難は吸気時に出現する(吸気性呼吸困難)。対照的に，胸郭内の気管･気管支に狭窄のある場合は，圧力関係は上気道の場合とまったく逆になり，呼気時に狭窄が増強され，呼気性呼吸困難を生ずる。…

※「吸気性呼吸困難」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典 第２版について | 情報