Gayrard P
Poumon Coeur. 1975;31(5):255-8.
Resistance of peripheral or "small" airways is only a small part of the total pulmonary resistance (Raw). Even considerable obstruction in these airways will have little effect on total resistance. Conversely this will lead to inequality in the time constants of units in parallel, and dynamic lung compliance (C dyn) shall fall as respiratory frequence increases. C dyn is measured from simultaneous recordings of transpulmonary pressure (esophageal balloon) and volume obtained from a volume displacement plethysmograph. If Raw and static compliance are found to be normal, the frequency dependance of compliance will result from peripheral airway obstruction only. Early stages of chronic airway obstruction can be established by this method. However this appear not suitable for wide-scale studies.
外周或“小”气道阻力仅占总肺阻力（气道阻力）的一小部分。即使这些气道出现相当程度的阻塞，对总阻力的影响也很小。相反，这将导致并行单位时间常数的不均等，并且动态肺顺应性（C dyn）会随着呼吸频率的增加而下降。C dyn通过同时记录经肺压（食管气囊）和从体积位移体积描记器获得的容积来测量。如果发现气道阻力和静态顺应性正常，顺应性的频率依赖性将仅由外周气道阻塞引起。慢性气道阻塞的早期阶段可以通过这种方法确定。然而，这似乎不适用于大规模研究。
