Central airway mechanics and flow limitation in acquired tracheobronchomalacia
Central airway mechanics and flow limitation in acquired tracheobronchomalacia
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DOI：
10.1378/chest.06-2556
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发表时间：
2007-04-01
期刊：
影响因子：
9.6
通讯作者：
Ernst, Armin
中科院分区：
文献类型：
--
作者：
Loring, Stephen H.;O'Donnell, Carl R.;Ernst, Armin
背景：获得性气管支气管软化症 (TBM) 可导致 COPD 患者中央气道塌陷，并可能加重气流阻塞和症状。通常不知道中央气道软化是否会导致气流阻塞。本研究的目的是量化中央气道塌陷性，并将其与 TBM 患者的呼气流量限制联系起来。方法：对 80 名接受 TBM 评估的患者和 4 名健康对照受试者进行研究，通过支气管镜录像带测量中央气道狭窄情况，并同时测量气管和食管的压力。通过形状指数评估气管狭窄并针对经气管绘制图。测量塌陷性的压力。随后，测量气流和跨肺压 (PL)，以确定安静呼吸期间的呼气流量限制，并确定最大呼气流量所需的临界 PL。结果：患者之间的气管塌陷度差异很大。有些人在安静呼吸时气管严重变窄，而另一些人仅在用力呼气时才表现出严重塌陷。在患者中，15% 的患者在安静呼吸期间未受到流量限制，53% 的患者在整个呼气过程中受到流量限制，30% 的患者仅在呼气的后半部分受到流量限制。静息时流量受限的患者比没有流量受限的患者表现出更大的气管狭窄（p = 0.009），但呼气流量受限的严重程度与气管塌陷性并不密切相关。 23 例患者在 PL 安静呼气时出现流量受限，但未引起中央气道塌陷。结论：在 TBM 中，中央气道塌陷与气流阻塞关系不密切，静息时呼气流量受限常发生在不伴有中央气道塌陷的外周气道。
Background: Acquired tracheobronchomalacia (TBM) can cause central airway collapse in patients with COPD and may worsen airflow obstruction and symptoms. it is usually not known whether central airway malacia contributes to airflow obstruction. This study was undertaken to quantify central airway collapsibility and relate it to expiratory flow limitation in patients with TBM.Methods: Eighty patients evaluated for acquired TBM and 4 healthy control subjects were studied with measurements of central airway narrowing derived from bronchoscopic videotapes and simultaneous pressure measurements in the trachea and esophagus. Tracheal narrowing was assessed by a shape index and plotted against the transtracheal. pressure to measure collapsibility. Subsequently, airflow and transpulmonary pressure (PL) were measured to identify expiratory flow limitation during quiet breathing and to determine the critical PL required for maximum expiratory flow.Results: Tracheal collapsibility varied widely among patients. Some had profound tracheal narrowing during quiet breathing, and others showed substantial collapse only during forced exhalation. Of the patients, 15% were not flow limited during quiet breathing, 53% were flow limited throughout exhalation, and 30% were flow limited only during the latter part of the exhalation. Patients with flow limitation at rest showed greater tracheal narrowing than those without (p = 0.009), but the severity of expiratory flow limitation was not closely related to tracheal collapsibility. Twenty-three patients were flow limited during quiet exhalation at PLs that did not cause central airway collapse.Conclusions: In TBM, central airway collapse is not closely related to airflow obstruction, and expiratory flow limitation at rest often occurs in peripheral airways without central airway collapse.