哮喘联盟

   摘要
   近年来人们特别关注小气道在哮喘和COPD的病理生理、临床表现和治疗中的作用。小气道在总气道阻力中几乎没有起到什么作用，因此小气道的广泛受损可能在没有任何症状之前就已经发生了，这也是为什么小气道也被称为气道“沉默区”。此外，小气道位于外周、半径小，导致很难直接对其进行评估。因此，人们常常利用阻塞小气道的影响来间接对其进行研究，如提早关闭、气体陷闭、通气功能异质性和气流受限的肺容积依赖性。目前，已经有几种不同方法可用于评估小气道。这些评估方案可以是功能性的（肺量测定法、体积描记法、阻力测定、氮洗脱、肺泡NO、频率依赖性肺顺应性、呼吸氦氧混合气流量－容积曲线），或影像学的（主要通过高分辨率CT）。上述提到的方法总结于表1中。但是，目前评估方法还没有“金标准”，需要联合几种方法进行评估。此外，哮喘或COPD患者小气道是否受损尚不明确，小气道的临床重要性也在研究中。哪种是评估小气道的最精确、最可靠和重复性最好的方法，这种方法适用于哪些人群，以及哪些方法可用于评估治疗疗效，这些问题还需要精心设计的大样本研究来解决。
 

（苏楠 审校）
RespirMed.2013Jun10.pii:S0954-6111(13)00175-3.doi:10.1016/j.rmed.2013.05.003. [Epub ahead of print]
 

Techniques for assessing small airways function: Possible applications in asthma and COPD.
 

Konstantinos Katsoulis K, Kostikas K, Kontakiotis T.
 

Abstract
In recent years special interest has been expressed for the contribution of small airways in the pathophysiology, clinical manifestations and treatment of asthma and COPD. Small airways contribute little to the total respiratory resistance so that extensive damage of small airways may occur before the appearance of any symptoms, and this is the reason why they are characterized as the "silent zone" of airways. Furthermore, the peripheral localization of the small airways and their small diameter constitutes difficult their direct assessment. Thus, they are usually studied indirectly, taking advantage of the effects of their obstruction, such as premature closure, air trapping, heterogeneity of ventilation, and lung volume dependence of airflow limitation. Today, several heterogeneous methods for the assessment of small airways are available. These can be either functional (spirometry, plethysmography, resistance measurements, nitrogen washout, alveolar nitric oxide, frequency dependence of compliance, flow-volume curves breathing mixture of helium-oxygen) or imaging (mainly through high resolution computed tomography). The above-mentioned methods are summarized in Table 1. However, no method is currently considered as the "gold standard" and it seems that combinations of tests are needed. Furthermore, it is not clear whether the small airways are affected in all patients with asthma or COPD and their clinical significance remains under investigation. Well-designed future studies with large numbers of patients are expected to reveal which of the methods for assessing the small airways is the most accurate, reliable and reproducible, for which patients, and which can be used for the evaluation of the effects of treatment.
 

RespirMed.2013Jun10.pii:S0954-6111(13)00175-3.doi:10.1016/j.rmed.2013.05.003. [Epub ahead of print]