Feihl F, Simon N, Jaeggi C, Depeursinge C, Perret C
Institut de Physiopathologie, Centre Hospitalier, Universitaire Vaudois, Lausanne, Switzerland.
J Appl Physiol (1985). 1988 Apr;64(4):1387-96. doi: 10.1152/jappl.1988.64.4.1387.
We investigated the relationship between the site of airway obstruction and the frequency dependence (FD) of lung acoustic impedance (ZL). The real (RL) and imaginary (XL) parts of ZL were measured by forced random noise in excised left pig lungs, before (base line) and after 1) no airway obstruction (controls, n = 10), 2) insufflation of 1-mm (B1, n = 5) or 2-mm (B2, n = 7) beads, and 3) partial reversible obstruction of lower lobar (LL) and then main-stem (MS) bronchus (n = 4). The beads caused both partial and total obstruction of airways with internal diameters of 2 mm (B1) and 2-6 mm (B2). Compared with base line, a negative FD of RL appeared from 4 to 10 Hz in LL, B1, and B2 obstructions. The FD of XL greater than 20 Hz increased in MS and LL obstruction exclusively and was the ZL feature that most clearly differentiated central from peripheral obstruction. In this experimental model, the anatomic limit distal from which obstruction no longer causes the "central" type of ZL change lies in airways with internal diameters notably greater than 2 mm.
我们研究了气道阻塞部位与肺声阻抗（ZL）频率依赖性（FD）之间的关系。在离体的猪左肺中，通过强迫随机噪声测量ZL的实部（RL）和虚部（XL），测量时间点为：1）无气道阻塞（对照组，n = 10）、2）注入1毫米（B1组，n = 5）或2毫米（B2组，n = 7）珠子后以及3）下叶（LL）和主支气管（MS）部分可逆性阻塞后（n = 4）的基线和之后。珠子导致内径为2毫米（B1）和2 - 6毫米（B2）的气道出现部分和完全阻塞。与基线相比，在LL、B1和B2阻塞中，RL在4至10赫兹出现负FD。仅在MS和LL阻塞中，XL大于20赫兹的FD增加，这是最能明确区分中央性与外周性阻塞的ZL特征。在该实验模型中，阻塞不再引起“中央”型ZL变化的远端解剖学界限位于内径明显大于2毫米的气道。
