Hoffstein V, Fredberg J J
Dept of Medicine, St. Michael's Hospital, Toronto, Canada.
Eur Respir J. 1991 May;4(5):602-11.
Non-invasive assessment of upper airway area by acoustic reflections has been developed in the last 12 yrs. The technique is based on the analysis of sound waves reflected from the airways. Measurement of the amplitudes of the reflections and their times of arrival at the sensing microphone permits construction of a plot of airway area vs distance from the microphone. We describe the theoretical foundations of the method and review the underlying assumptions. This is followed by a summary of the results of in vitro and in vivo validation studies, with particular attention to the reproducibility, accuracy and variability of the technique. The description of clinical and physiological applications of this technique includes detection of tracheal stenosis, demonstration of structural and functional abnormalities of the pharynx and glottis in patients with sleep apnoea, dichotomous response of the airway area to exercise, and airway vs parenchymal hysteresis. Finally, we comment on the future directions that might be investigated using this technique.
在过去12年中，已开发出通过声学反射对气道面积进行无创评估的技术。该技术基于对从气道反射的声波的分析。测量反射的幅度及其到达传感麦克风的时间，可以构建气道面积与距麦克风距离的关系图。我们描述了该方法的理论基础，并回顾了其基本假设。接下来是体外和体内验证研究结果的总结，特别关注该技术的可重复性、准确性和变异性。对该技术临床和生理应用的描述包括气管狭窄的检测、睡眠呼吸暂停患者咽部和声门结构及功能异常的显示、气道面积对运动的二分反应以及气道与实质的滞后现象。最后，我们对使用该技术可能进行研究的未来方向进行了评论。
