A nonlinear model of respiratory mechanics in emphysematous lungs.
A nonlinear model of respiratory mechanics in emphysematous lungs.
复制标题
肺气肿肺呼吸力学的非线性模型。
DOI：
10.1007/bf02364579
复制
发表时间：
1988
影响因子：
3.8
通讯作者：
Chang,HK
中科院分区：
文献类型：
--
作者：
Tawfik,B;Chang,HK
现有的慢性阻塞性肺疾病的力学模型不能解释一些呼吸道阻塞的实验结果，例如，阻力的频率依赖性(FDR)的不同方式。本文从平行单位的概念出发，试图解释肺气肿肺的“止回阀”机制，提出了一个具有非线性压力-流量关系的单室肺模型：$P+P*=L\dDOT V+K_1\点V+K_3(\点V\PM\点V*)^3+V/c$，其中有一个常数。三次项中的正号和负号分别表示呼气和吸气止回阀。选择不对称关系反映了肺气肿的几个特性，如气流受限和较高的呼气阻力。使用正弦波、白噪声和阶跃输入实现上述方程时，根据所使用的输入类型，在0至40赫兹之间的频率处产生各种形式的FDR。电阻对输入压力幅值的变化最为敏感。该模型的结果表明，在阻塞性肺疾病中，非线性可以对阻抗结构产生重大影响。
Existing mechanical models of chronic obstructive lung disease have failed to explain a number of experimental findings of airway obstruction, e.g., the varying manners of frequency dependence of resistance (FDR). Departing from the parallelunit concept and attempting to account for the “check-valve” mechanism in the emphysematous lung, we proposed a single-compartment lung model with a nonlinear pressure-flow relationship: $$P + P* = L\ddot V + K_1 \dot V + K_3 (\dot V \pm \dot V*)^3 + V/c$$ , whereis a constant. The plus and minus signs in the cubic term indicate the expiratory and inspiratory check valves, respectively. The choice of an asymmetricrelation reflects several properties of emphysematous lungs such as airflow limitation and higher expiratory resistance. Implementation of the above equation using sine wave, white noise, and step inputs resulted in various forms of FDR at frequencies between 0 and 40 Hz depending on the type of input used. Resistance was most sensitive to changes in input pressure amplitude. The model's results suggest that thenonlinearity can have a significant influence on the impedance construct in obstructed lung disease.