Jackson A C
Fed Proc. 1980 Aug;39(10):2741-6.
Cross-sectional areas of airways vary with distance from the airway opening to alveoli. Existing techniques for estimating the serial distribution of airway cross section are invasive or depend on interpretations of indirect measurements. A rapid, noninvasive technique based on acoustic impedance data for estimating airway cross section as a function of distance has been described. Cross-sectional areas returned by this technique from measurements in a positive cast of human central airways out to subsegmental bronchi corresponded closely with areas determined from direct measurements. In vagotomized dogs, measurements indicate that vagal stimulation results in reduction of airway cross section at all distances, whereas histamine aerosol caused bronchoconstriction only at larger distances (i.e., peripheral airways). Vagotomy in the dog results in an apparent dilation in most airways to areas twice those in the control state. This increase in airway cross section is larger than has been reported previously. Measurements in humans indicate an apparent overestimation in tracheal cross-sectional areas. These findings might be caused by overestimations in area due to airway wall compliance in the intact human and in the dog without vagal tone. This technique may still be capable of providing useful information about the serial distribution of airway properties.
气道的横截面积随从气道开口到肺泡的距离而变化。现有的估计气道横截面积系列分布的技术具有侵入性，或者依赖于对间接测量结果的解读。一种基于声阻抗数据的快速、非侵入性技术已被描述，用于估计气道横截面积随距离的变化。该技术在人类中央气道直至亚段支气管的阳性铸型测量中返回的横截面积，与直接测量确定的面积密切对应。在迷走神经切断的狗身上，测量表明迷走神经刺激会导致所有距离处的气道横截面积减小，而组胺气雾剂仅在较大距离（即外周气道）引起支气管收缩。狗的迷走神经切断术导致大多数气道明显扩张至对照状态下面积的两倍。气道横截面积的这种增加比之前报道的更大。在人类中的测量表明气管横截面积明显被高估。这些发现可能是由于完整人类和无迷走神经张力的狗的气道壁顺应性导致面积被高估所致。该技术仍可能能够提供有关气道特性系列分布的有用信息。
