Nakagawa Misa, Hattori Noboru, Haruta Yoshinori, Sugiyama Aya, Iwamoto Hiroshi, Ishikawa Nobuhisa, Fujitaka Kazunori, Murai Hiroshi, Tanaka Junko, Kohno Nobuoki
Department of Molecular and Internal Medicine, Institute of Biomedical & Health Sciences, Hiroshima University, Hiroshima, Japan.
Respirology. 2015 Jan;20(1):87-94. doi: 10.1111/resp.12387. Epub 2014 Sep 23.
Airway resistance and reactance measured by forced oscillometry have been used to measure the severity of airway obstruction in chronic obstructive pulmonary disease (COPD) patients. The aims of this study were to assess the effects of tachypnoea on airway resistance and reactance and to correlate these with the severity of dyspnoea. We also evaluated the effects of short-acting β2-agonist (SABA) on these measurements.
Airway resistance and reactance were measured with an impulse oscillation system (IOS) in 20 COPD and 10 control participants during resting respiration and metronome-paced breathing at 20, 30 and 40 tidal breaths/min. The same measurements were made for COPD patients after SABA inhalation. Dyspnoea was evaluated using the modified Medical Research Council (MRC) scale.
In patients with COPD, higher respiratory rates increased expiratory and inspiratory resistance at 5 Hz (R5), the difference in respiratory resistance at 5 Hz and 20 Hz (R5-R20), resonant frequency and decreased expiratory reactance. The decreases in expiratory reactance from 20 to 40 tidal breaths/min were significantly correlated with MRC scores. SABA inhalation significantly reduced the effect of increased respiratory rate on the reactance measurements.
Characteristic changes in IOS measurements, particularly expiratory reactance, induced by increased respiratory rates, were correlated with severity of dyspnoea in COPD patients during their daily lives. IOS and paced breathing may be useful for assessing breathlessness in COPD.
通过强迫振荡法测量的气道阻力和电抗已被用于评估慢性阻塞性肺疾病（COPD）患者气道阻塞的严重程度。本研究的目的是评估呼吸急促对气道阻力和电抗的影响，并将这些影响与呼吸困难的严重程度相关联。我们还评估了短效β2受体激动剂（SABA）对这些测量结果的影响。
使用脉冲振荡系统（IOS）在20名COPD患者和10名对照参与者静息呼吸以及以每分钟20、30和40次潮气呼吸的节拍器控制呼吸时测量气道阻力和电抗。对COPD患者吸入SABA后进行相同的测量。使用改良的医学研究委员会（MRC）量表评估呼吸困难情况。
在COPD患者中，较高的呼吸频率会增加5Hz时的呼气和吸气阻力（R5）、5Hz和20Hz时呼吸阻力的差值（R5-R20）、共振频率，并降低呼气电抗。从每分钟20次潮气呼吸增加到40次时呼气电抗的降低与MRC评分显著相关。吸入SABA可显著降低呼吸频率增加对电抗测量结果的影响。
IOS测量中的特征性变化，尤其是呼吸频率增加引起的呼气电抗变化，与COPD患者日常生活中呼吸困难的严重程度相关。IOS和节律性呼吸可能有助于评估COPD患者的呼吸急促情况。
