MECHANICAL FACTORS IN DISTRIBUTION OF PULMONARY VENTILATION
MECHANICAL FACTORS IN DISTRIBUTION OF PULMONARY VENTILATION
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DOI：
10.1152/jappl.1956.8.4.427
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发表时间：
1956-01-01
影响因子：
3.3
通讯作者：
RADFORD, EP
中科院分区：
文献类型：
--
作者：
OTIS, AB;MCKERROW, CB;RADFORD, EP
假设肺可以用一组通路机械地表示，每个通路由串联连接的顺应性C和阻力R组成。这种系统的行为的理论分析开发使用的方法，可用于类比电路。该分析表明，除非单独的通路具有相似的时间常数（RC乘积），否则当暴露于相同的驱动压力时，它们将在时间和空间上不均匀地通风。在由具有不等时间常数的通路组成的系统中，通气的分布以及有效顺应性和阻力将随着呼吸频率而变化。这种行为是由两个平行的路径组成的力学模型证明。在对正常人受试者的测量中，肺的有效顺应性显示出与呼吸频率无关。在诱发支气管痉挛的个体和肺气肿或哮喘患者中，有效依从性随着频率的增加而降低。根据该理论，这些结果表明，在正常肺中，单独通路的时间常数是相似的，并且通气量在所有频率下均匀分布，但在所研究的异常情况下，存在时间常数的不平等，并且通气量的分布随着呼吸频率的变化而改变。
The assumption is made that the lungs can be represented mechanically by a population of pathways each consisting of a compliance, C, and a resistance, R, connected in series. A theoretical analysis of the behavior of such a system is developed using methods which are available for analagous electrical circuits. This analysis indicates that unless the separate pathways have similar time constants (RC product) they will, when exposed to the same driving pressure, be unevenly ventilated both temporally and spatially. In a system composed of pathways having unequal time constants, the distribution of ventilation and the effective compliance and resistance will vary with frequency of breathing. This behavior was demonstrated by a mechanical model consisting of two parallel pathways. In measurements on normal human subjects the effective compliance of the lungs was shown to be invariant with frequency of breathing. In individuals with induced broncho-spasm and in patients with emphysema or asthma effective compliance decreased with increasing frequency. In the light of the theory these results suggest that in normal lungs the time constants of the separate pathways are similar and that ventilation is evenly distributed at all frequencies, but that in the abnormal cases studied inequalities of time constants exist and that distribution of ventilation alters with changes in breathing frequency.