Relating maximum airway dilation and subsequent reconstriction to reactivity in human lungs
Relating maximum airway dilation and subsequent reconstriction to reactivity in human lungs
复制标题
DOI：
10.1152/japplphysiol.01170.2003
复制
发表时间：
2004-05-01
影响因子：
3.3
通讯作者：
Lutchen, KR
中科院分区：
文献类型：
--
作者：
Black, LD;Henderson, AC;Lutchen, KR
深度吸气（DI）时气道阻力（Raw）的测量表明哮喘受试者具有更僵硬，反应性更强的气道平滑肌。有证据表明，一个人可以提高气道反应性，在健康的肺部通过长期禁止DI。目前的研究有两个目标。首先，我们确定哮喘受试者的最大扩张能力是否取决于DI的速率。其次，我们调查了健康人群中增强的反应性是否可能来自哮喘患者中不存在的其他机制。为了实现第一个目标，我们对7名健康受试者和7名哮喘受试者进行了未经指导的人工呼吸、5至10秒全肺容量憋气的人工呼吸和快速人工呼吸。我们发现在全肺活量下获得的最小阻力与进行DI的方式无关。对于第二个目标，我们跟踪了人工呼吸后Raw的恢复率以及人工呼吸前后、基线和支气管刺激后的动态肺弹性。di后肺弹性下降表明肺部区域重新开放和/或异质性降低。数据显示收缩的健康但非哮喘受试者产生更持久的残余扩张。因此，健康受试者对禁用DI的反应性增强的一部分可能是由于气道关闭和/或肺不张，可以用DI消融。我们的结论是，预防DIs并不能确保健康受试者完全过渡到哮喘样的高反应性肺状态。
Measures of airway resistance (Raw) during deep inspiration (DI) suggest that asthmatic subjects possess stiffer, more reactive airway smooth muscle. There is evidence that one can enhance airway reactivity in healthy lungs by prohibiting DI for an extended period. The present study had two goals. First, we determined whether the maximum dilation capacity of asthmatic subjects depended on the rate of the DI. Second, we investigated whether the enhanced reactivity in healthy humans might derive from additional mechanisms not present in asthmatic subjects. For the first goal, we tracked Raw in seven healthy and seven asthmatic subjects during a noncoached DI, a DI with a 5- to 10-s breath hold at total lung capacity, and a rapid DI. We found that the minimum resistance achieved at total lung capacity was independent of the manner in which the DI was performed. For the second goal, we tracked the rate of return of Raw after a DI as well as dynamic lung elastance before and after the DI, at baseline and after bronchial challenge. A drop in lung elastance post-DI would indicate reopening of lung regions and/or reduced heterogeneities. The data show that constricted healthy but not asthmatic subjects produce longer lasting residual dilation. Hence, a portion of the enhanced reactivity in a healthy subject's response to prohibition of DIs is likely due to airway closure and/or atelectasis that can be ablated with a DI. We conclude that preventing DIs does not ensure that healthy subjects will transition entirely to an asthmatic-like hyperreactive lung state.