喘鳴聲是兒童呼吸道的常見症狀，若無正確診斷可能造成呼吸衰竭，甚至生命危險。本案例是一位18個月男童，曾在2次因呼吸衰竭留置氣管內管之插管史，經支氣管擴張劑及類固醇治療後， 仍再次引發喘鳴聲，甚至出現胸骨凹陷，行胸腔電腦斷層發現聲門下狹窄，案童經手術治療後喘鳴聲明顯改善，且出院後3個月內無再發作。因此，當我們遇到氣管內管插管史的兒童，出現喘鳴聲持續72小時以上合併胸骨凹陷，加上對支氣管擴張劑或類固醇等藥物效果不佳時，聲門下狹窄就必須列入考慮。

Stridor is a common symptom of the respiratory system in children that might cause respiratory fail­ure and precipitate life-threatening if not properly diagnosed. An 18-month-old child had 2 times of the endotracheal tube intubation history. After treatment with bronchodilators and steroids, recurrent stridor and sternal depression were discovered. Thoracic computed tomography was performed and re­vealed subglottic stenosis. After surgical intervention of cricotracheal resection, the child’s stridor was significantly improved and no recurrence within 3 months after discharge. Therefore, children with a history of endotracheal tube intubation, who had stridor more than 72 hours with sternal depression or poor response for bronchodilators and steroids, the possibility of subglottic stenosis should be consid­ered in the differential diagnosis