Rubinstein I, Zamel N, Rebuck A S, Hoffstein V, D'Urzo A D, Slutsky A S
Department of Medicine, Mt. Sinai Hospital Research Institute, Toronto, Ontario, Canada.
Am Rev Respir Dis. 1988 Nov;138(5):1164-8. doi: 10.1164/ajrccm/138.5.1164.
The extent and location of airway narrowing in asthmatic subjects are usually inferred from measurements of maximal expiratory flow rates and airway resistance. In the present study, we used the acoustic reflection technique to measure the airway cross-sectional area in 14 asthmatic subjects and 8 normal controls before and following treadmill exercise tests. In normal subjects, exercise caused no significant change in FEV1 and bronchial area, but did cause a significant increase in the intrathoracic tracheal area from 2.0 +/- 0.7 cm2 to 3.1 +/- 0.7 cm2 (p less than 0.002). In the asthmatics, exercise was followed by a 37 +/- 15% reduction in forced expiratory volume in 1 s(FEV1), and a 36% decrease in bronchial area from 8.5 +/- 2.8 cm2 to 5.4 +/- 1.1 cm2 (p less than 0.001); however, extra- and intrathoracic tracheal areas increased significantly. These findings provide direct and quantitative evidence that the bronchi are the main site of airway narrowing in exercise-induced asthma, and draw attention to the phenomenon of tracheal dilatation that occurs concomitant with bronchoconstriction in asthmatic patients.
哮喘患者气道狭窄的程度和部位通常通过最大呼气流量率和气道阻力的测量来推断。在本研究中，我们运用声反射技术，在跑步机运动试验前后，对14名哮喘患者和8名正常对照者的气道横截面积进行了测量。在正常受试者中，运动导致第一秒用力呼气容积（FEV1）和支气管面积无显著变化，但胸腔内气管面积从2.0±0.7平方厘米显著增加至3.1±0.7平方厘米（p<0.002）。在哮喘患者中，运动后第一秒用力呼气容积（FEV1）降低了37±15%，支气管面积从8.5±2.8平方厘米减少了36%至5.4±1.1平方厘米（p<0.001）；然而，胸外和胸腔内气管面积显著增加。这些发现提供了直接和定量的证据，表明支气管是运动诱发哮喘时气道狭窄的主要部位，并提请注意哮喘患者在支气管收缩时伴随发生的气管扩张现象。
