Coté M C, Sériès F, Laviolette M, Laberge F, Atton L, Cormier Y
Unité de Recherche, Centre de Pneumologie de l'Hôpital Laval, Université Laval, Québec, Canada.
Eur J Clin Invest. 1994 Dec;24(12):837-42. doi: 10.1111/j.1365-2362.1994.tb02028.x.
We tested the hypothesis that lung inflation in response to a bronchospasm could be beneficial by maintaining the lung collateral channels open. Six mild asthmatics were studied on 2 separate days. The first day we determined the methacholine dose response and measured collateral resistance (Rcoll) before and during the metacholine-induced bronchospasm and the effects of decreasing lung volumes on Rcoll. The lung volume changes were induced by applying progressively increasing positive extrathoracic pressures (PEP). The second day we measured the changes in end-expiratory lung volume (EELV) resulting from the inhaled methacholine and from the applied positive extrathoracic pressure. With the inhalation of methacholine, the FEV1 decrease ranged from 26-43% of the baseline values while Rcoll increased significantly in only three of the six subjects. EELV remained unchanged in one subject and increased by 1408, 990, 260, and 44 ml in four others. It was not measured in one subject. Decreasing EELV by PEP increased Rcoll in all subjects. By extrapolation of the lung volume-Rcoll relationship, we calculated that Rcoll would have increased by 18,227%, 6843%, 994%, 140%, and 128% if EELV had not increased in the five subjects in whom delta EELV was measured. We conclude that an increase in EELV in response to an induced bronchospasm helps maintain open and functional collateral pathways despite the bronchoconstriction.
我们验证了这样一个假设，即因支气管痉挛而导致的肺膨胀通过维持肺侧支通道开放可能是有益的。我们在两个不同的日子对六名轻度哮喘患者进行了研究。第一天，我们测定了乙酰甲胆碱剂量反应，并在乙酰甲胆碱诱发支气管痉挛之前和期间测量了侧支阻力（Rcoll），以及降低肺容积对Rcoll的影响。肺容积变化是通过逐渐增加胸外正压（PEP）来诱发的。第二天，我们测量了吸入乙酰甲胆碱以及施加胸外正压后呼气末肺容积（EELV）的变化。吸入乙酰甲胆碱后，第一秒用力呼气量（FEV1）下降幅度为基线值的26% - 43%，而在六名受试者中只有三名的Rcoll显著增加。一名受试者的EELV保持不变，另外四名受试者的EELV分别增加了1408、990、260和44毫升。有一名受试者未测量该指标。通过PEP降低EELV会使所有受试者的Rcoll增加。通过推断肺容积与Rcoll的关系，我们计算得出，如果在测量了EELV变化量的五名受试者中EELV没有增加，那么Rcoll会分别增加18227%、6843%、994%、140%和128%。我们得出结论，尽管存在支气管收缩，但因诱发的支气管痉挛而导致的EELV增加有助于维持侧支通道开放并使其发挥功能。
