Fredberg J J, Wohl M E, Glass G M, Dorkin H L
J Appl Physiol Respir Environ Exerc Physiol. 1980 May;48(5):749-58. doi: 10.1152/jappl.1980.48.5.749.
We tested the hypothesis that features of upper airway and tracheal geometry can be inferred from acoustic reflection data recorded at the mouth. In six subjects we computed inferences of airway cross-sectional area vs. distance and compared them with measurements obtained from orthogonal radiographic projections of the trachea. The acoustic data show local area maxima at the uvula and hypopharynx and local minima at the oropharynx and the glottis. With subjects breathing air the inferred tracheal areas markedly exceeded the radiographic measurements. With subjects breathing 80% He-20% O2 there was good intrasubject agreement between acoustic and radiographic data in spite of large intersubject variability. The average coefficient of variation of tracheal area determinations for five trials in all subjects was 0.16. These studies suggest that features of airway geometry between the mouth and carina can be determined accurately and noninvasively in individual subjects from high-frequency reflection data measured at the mouth.
我们检验了这样一个假设，即可以从口腔记录的声反射数据推断上呼吸道和气管的几何特征。在六名受试者中，我们计算了气道横截面积与距离的推断值，并将其与从气管的正交射线投影获得的测量值进行比较。声学数据显示，悬雍垂和下咽处存在局部面积最大值，口咽和声门处存在局部最小值。当受试者呼吸空气时，推断的气管面积明显超过射线测量值。当受试者呼吸80%氦-20%氧气时，尽管受试者间存在较大差异，但声学数据和射线数据在受试者内部仍有良好的一致性。所有受试者五次试验中气管面积测定的平均变异系数为0.16。这些研究表明，可以根据在口腔测量的高频反射数据，准确且无创地确定个体受试者口腔和隆突之间气道几何结构的特征。
