Molfino N A, Slutsky A S, Julià-Serdà G, Hoffstein V, Szalai J P, Chapman K R, Rebuck A S, Zamel N
Department of Medicine, University of Toronto, Ontario, Canada.
Am Rev Respir Dis. 1993 Nov;148(5):1238-43. doi: 10.1164/ajrccm/148.5.1238.
We investigated the hypothesis that asthmatic patients have an increased cholinergic tone by measuring tracheobronchial cross-sectional areas during transient voluntary apnea. This allowed us to assess bronchomotor tone without the influence of changes in lung recoil or lung volume. Three groups of subjects with potentially different levels of tracheobronchial tone were studied: 14 healthy volunteers (N), 18 stable asthmatic patients (A), and 10 double lung transplant recipients (T). Using the acoustic reflection technique, we measured changes in tracheobronchial cross-sectional areas during short periods (5 to 10 s) of voluntary apnea. In a subset of subjects, studies were repeated before and after the inhalation of the muscarinic antagonist ipratropium. During breath-holding, glottis and extrathoracic trachea remained unchanged but intrathoracic tracheal area decreased by 30 +/- 8% (mean +/- standard error of the mean) in N, by 27 +/- 3% in A, and by 9 +/- 4% in the T group. Bronchial areas decreased by 24 +/- 8% in N, by 45 +/- 3% in A, and by 10 +/- 4% in T. These differences among groups were statistically significant at the tracheal and bronchial levels (p < 0.05), and ipratropium significantly inhibited this airway constriction (p < 0.05) only in the asthmatic group. Assuming that changes in cross-sectional airway areas voluntary apnea reflect airway tone, these results support the view that in humans this tone is mainly vagally controlled and that it is significantly increased in asthmatic compared with nonasthmatic subjects.
我们通过在短暂的自主屏气期间测量气管支气管横截面积，来研究哮喘患者胆碱能张力增加这一假说。这使我们能够在不受肺回缩或肺容积变化影响的情况下评估支气管运动张力。我们研究了三组气管支气管张力水平可能不同的受试者：14名健康志愿者（N组）、18名稳定期哮喘患者（A组）和10名单肺移植受者（T组）。我们使用声学反射技术，测量了自主屏气短时间（5至10秒）内气管支气管横截面积的变化。在一部分受试者中，在吸入毒蕈碱拮抗剂异丙托溴铵前后重复进行了研究。在屏气期间，声门和胸外气管保持不变，但N组胸内气管面积减少了30±8%（平均值±平均标准误差），A组减少了27±3%，T组减少了9±4%。支气管面积在N组减少了24±8%，在A组减少了45±3%，在T组减少了10±4%。各组之间在气管和支气管水平的这些差异具有统计学意义（p<0.05），并且异丙托溴铵仅在哮喘组中显著抑制了这种气道收缩（p<0.05）。假设自主屏气时气道横截面积的变化反映气道张力，这些结果支持以下观点：在人类中，这种张力主要受迷走神经控制，并且与非哮喘受试者相比，哮喘患者的这种张力显著增加。
