A New Method To Assess Lung Volume Dependency Of Respiratory System Resistance Using Forced Oscillation
A New Method To Assess Lung Volume Dependency Of Respiratory System Resistance Using Forced Oscillation
复制标题
一种利用受迫振荡评估呼吸系统阻力肺容量依赖性的新方法
DOI:
10.1164/ajrccm-conference.2010.181.1_meetingabstracts.a1240
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发表时间:
2010
期刊:
影响因子:
--
通讯作者:
W. Hida
中科院分区:
文献类型:
--
作者:
H. Kurosawa;J. Ohishi;Y. Shimizu;Y. Tasaku;Daisuke Kobayashi;M. Masuda;Masashi Kanezaki;Etuhiro Nikkuni;M. Kohzuki;W. Hida
Airway resistance is lung volume dependent. The bronchi are supported by the radial traction of the surrounding lung tissue, and their caliber is increased as the lung expands. The high resistance should be observed at low lung volume such as residual volume (RV) while the low at the high lung voume such as total lung capacity (TLC). In patients with ventilatory uneveness or high airway resistance such as chronic obstructive pulmonary disease (COPD), the dependency could be prominent especially at the lower lung volume near RV. To assess these physiological and pathophysiological properties, a new method was designed. Instead of airway resistance, respiratory system resistance (Rrs) was measured with forced oscillation technique using a commertially available machine (MostGraph-01, Chest MI co. ltd., Tokyo, Japan). Impulse oscillatory signals at the intervals of 0.25 second were applied to obtain Rrs properties against oscillatory frequency ranged from 5 to 35 Hz. Because the Rrs curves were possible to be obtaied in every 0.25 second, those were serially lined up along time axis, resulted in 3 dimensional imaging pattern of Rrs. Using this machine, simple quasi-static measurements were performed in healthy volunteers. The subjects were advised to expirate slowly at the approximate flow rate of 0.2 L/min from TLC to RV. All the subjects showed the minimum Rrs at TLC and the maximum at RV, which clearly showed lung volume dependent Rrs changes. The dependency was mild in the healthy younger subjects compared to the older, that possibly reflected less inhomogenous ventilatory mechanics in the younger subjects. Because this was very simple, easy, and non-invasive way, the future application can be widely expected as a very useful physiological tool in such a situation to screen the early COPD or very mild asthma. Lung volume dependent changes of Rrs properties