Harris R S
J Can Assoc Radiol. 1985 Jun;36(2):103-9.
Correlation of chest radiographic appearances with concurrent fibreoptic bronchoscopy in patients observed while in intensive care, and with lobar or multilobar atelectasis due to retained secretions, suggests that three levels of air bronchogram can be identified: Proximal: air is visible only to the level of the main bronchus, bronchus intermedius or lobar bronchi. Intermediate: air is visible down to the segmental bronchi. Distal: air is visible down to the subsegmental bronchi or beyond. Proximal or intermediate air bronchograms signify accumulation of secretions in central bronchi and indicate the need for fibreoptic bronchoscopy to aspirate secretions: a distal air bronchogram signifies peripheral bronchial obstruction thus precluding effective fibreoptic bronchoscopy; chest physiotherapy is then a more appropriate treatment. The proximal air bronchogram may change in extent or definition-sometimes rapidly; a receding or an increasingly poorly defined proximal air bronchogram are danger signals of centrally accumulating secretions which may lead to respiratory arrest.
在重症监护期间对患者进行观察时，胸部X光表现与同期纤维支气管镜检查结果以及因分泌物潴留导致的肺叶或多肺叶肺不张之间的相关性表明，可以识别出三种气支气管征水平：近端：仅在主支气管、中间支气管或肺叶支气管水平可见气体。中间：气体可见至段支气管水平。远端：气体可见至亚段支气管或更远处。近端或中间气支气管征表示中央支气管内有分泌物积聚，提示需要进行纤维支气管镜检查以吸出分泌物；远端气支气管征表示外周支气管阻塞，因此无法进行有效的纤维支气管镜检查；此时胸部物理治疗是更合适的治疗方法。近端气支气管征的范围或清晰度有时可能会迅速改变；近端气支气管征退缩或清晰度越来越差是中央分泌物积聚的危险信号，可能导致呼吸骤停。
