喘息是气流通过狭窄气道受阻形成涡流,引起气道壁震动而产生。由于小气道中主要流速的线形速度太慢,以至于不能产生在听觉范围内感知气道壁震动的能量,因此认为喘息来源于中心气道的狭窄。但因小气道总面积远远大于中心气道,小气道狭窄时阻力成倍增加,常常使大气道动力性受压, Breathing is the airflow through the narrow airway blocked formation of eddy currents, causing airway wall vibration generated. Because the linear velocity of the main flow velocity in the small airways is too slow to produce the energy that senses the vibration of the airway wall within the auditory range, it is assumed that the wheeze originates from the narrowing of the central airway. However, the total area of ​​small airways is much larger than the central airway, narrowing of small airways when the resistance doubled, often make the dynamic pressure of the airways,