Mishima M, Kawakami K, Hirai T, Takubo Y, Sakai H, Nakano Y, Muro S, Oku Y, Chin K, Ohi M
Department of Physical Therapeutics, Kyoto University Hospital, Japan.
Front Med Biol Eng. 1999;9(1):63-73.
The effect of positive airway pressure (5.0 hPa) on airway impedance (Za) and tissue impedance (Zt) during the expiratory phase in chronic obstructive pulmonary disease (COPD) patients was evaluated using random noise oscillation and a body box method. The results were then compared with those obtained from normal subjects. In normal subjects, there was no significant difference between non-expiratory positive pressure (NPEP) and positive expiratory pressure (PEP) for the Zar (real part) and Zai (imaginary part) at 10 Hz (Zar NPEP: 2.14 +/- 0.76, PEP: 1.96 +/- 0.79; Zai NPEP: 1.42 +/- 0.66, PEP: 1.40 +/- 0.70 hPa l-1 s). However, in COPD patients, Zar decreased significantly and the Zai increased significantly during PEP as compared to the values during NPEP (Zar NPEP: 7.10 +/- 1.88, PEP: 5.97 +/- 1.67, P < 0.05; Zai NPEP: -4.10 +/- 2.27, PEP: -2.99 +/- 2.62 hPa l-1 s, P < 0.05). These results suggested that both central and peripheral airway resistance decreased during PEP in COPD patients. Tissue compliance (Ct) calculated from the Zt increased significantly during PEP as compared to during NPEP, in both normal subjects and in COPD patients (normal NPEP: 0.024 +/- 0.004, PEP: 0.021 +/- 0.003, P < 0.05; COPD NPEP: 0.024 +/- 0.004, PEP: 0.014 +/- 0.004 l hPa-1, P < 0.001). This may have been indicative of the stiffened chest wall during PEP.
采用随机噪声振荡和体箱法评估了气道正压（5.0 hPa）对慢性阻塞性肺疾病（COPD）患者呼气期气道阻抗（Za）和组织阻抗（Zt）的影响。然后将结果与正常受试者的结果进行比较。在正常受试者中，非呼气正压（NPEP）和呼气正压（PEP）状态下，10 Hz时Zar（实部）和Zai（虚部）无显著差异（Zar NPEP：2.14±0.76，PEP：1.96±0.79；Zai NPEP：1.42±0.66，PEP：1.40±0.70 hPa l-1 s）。然而，在COPD患者中，与NPEP期间的值相比，PEP期间Zar显著降低，Zai显著增加（Zar NPEP：7.10±1.88，PEP：5.97±1.67，P<0.05；Zai NPEP：-4.10±2.27，PEP：-2.99±2.62 hPa l-1 s，P<0.05）。这些结果表明，COPD患者在PEP期间中央和外周气道阻力均降低。与NPEP期间相比，正常受试者和COPD患者在PEP期间由Zt计算得出的组织顺应性（Ct）均显著增加（正常受试者NPEP：0.024±0.004，PEP：0.021±0.003，P<0.05；COPD患者NPEP：0.024±0.004，PEP：0.014±0.004 l hPa-1，P<0.001）。这可能表明PEP期间胸壁变硬。
