Bhansali P V, Irvin C G, Dempsey J A, Bush R, Webster J G
J Appl Physiol Respir Environ Exerc Physiol. 1979 Jul;47(1):161-8. doi: 10.1152/jappl.1979.47.1.161.
We have investigated a new technique that could be specific for detecting small airway diseases. We measured resistance in nine subjects, evaluating the effect of breathing 80% He-20%O2, air, and 80% SF6-20% O2 at different flow rates (0.25--1.01 l/s) and frequencies (4--12 Hz). To test the sensitivity and specificity of this new technique, we used intravenous histamine infusion to cause peripheral constriction. During histamine infusion six of nine subjects showed the following changes: 1) dynamic compliance decreased; 2) subjects developed frequency dependence of compliance, and 3) there was no significant change in pulmonary resistance or Rrs (respiratory resistance) at 4 Hz. These data suggested a time-constant discrepancy in the periphery due to histamine infusion. These six subjects also developed frequency dependence of resistance (delta Rrs from 4 to 12 Hz), which was significant when breathing air (-22 +/- 6%) and maximal when we used He-O2 (-32 +/- 3%). We conclude that He-O2 can improve the specificity of frequency dependence of Rrs for detecting events occurring in the peripheral airways.
我们研究了一种可能对检测小气道疾病具有特异性的新技术。我们测量了9名受试者的阻力，评估了在不同流速（0.25 - 1.01升/秒）和频率（4 - 12赫兹）下呼吸80%氦 - 20%氧气、空气以及80%六氟化硫 - 20%氧气的效果。为了测试这项新技术的敏感性和特异性，我们通过静脉注射组胺来引起外周血管收缩。在注射组胺过程中，9名受试者中有6名出现了以下变化：1）动态顺应性降低；2）受试者出现顺应性的频率依赖性，并且3）在4赫兹时肺阻力或呼吸阻力（Rrs）无显著变化。这些数据表明由于注射组胺在外周出现了时间常数差异。这6名受试者还出现了阻力的频率依赖性（4至12赫兹时的Rrs变化），在呼吸空气时显著（-22±6%），在使用氦 - 氧气时最大（-32±3%）。我们得出结论，氦 - 氧气可以提高Rrs频率依赖性对检测外周气道中发生事件的特异性。
