The high-frequency vibration of the air-filled vest loosens secretions and creates friction between the air and mucus, which helps move secretions from the lower lungs to the upper airways.

• 充满气体的高频率震动背心能减少分泌，在空气与黏膜之间引起摩擦，好让分泌物从肺部下方移到上呼吸道；