Balleza Marco, Calaf Núria, Feixas Teresa, González Mercedes, Antón Daniel, Riu Pere J, Casan Pere
Departament de Pneumologia, Hospital de la Santa Creu i de Sant Pau, Facultat de Medicina, Universitat Autònoma de Barcelona, Barcelona, España.
Arch Bronconeumol. 2009 Jul;45(7):320-4. doi: 10.1016/j.arbres.2009.01.013. Epub 2009 Jun 3.
The measurement of breathing pattern in patients with chronic obstructive pulmonary disease (COPD) by electrical impedance tomography (EIT) requires the use of a mathematical calibration model incorporating not only anthropometric characteristics (previously evaluated in healthy individuals) but probably functional alterations associated with COPD as well. The aim of this study was to analyze the association between EIT measurements and spirometry parameters, static lung volumes, and carbon monoxide diffusing capacity (DLCO) in a group of male patients to develop a calibration equation for converting EIT signals into volume signals.
We measured forced vital capacity (FVC), forced expiratory volume in 1 second (FEV(1)), FEV(1)/FVC, residual volume, total lung capacity, DLCO, carbon monoxide transfer coefficient (KCO) and standard anthropometric parameters in 28 patients with a FEV(1)/FVC ratio of <70%. We then compared tidal volume measurements from a previously validated EIT unit and a standard pneumotachometer.
The mean (SD) lung function results were FVC, 72 (16%); FEV(1), 43% (14%); FEV(1)/FVC, 42% (9%); residual volume, 161% (44%); total lung capacity, 112% (17%); DLCO, 58% (17%); and KCO, 75% (25%). Mean (SD) tidal volumes measured by the pneumotachometer and the EIT unit were 0.697 (0.181)L and 0.515 (0.223)L, respectively (P<.001). Significant associations were found between EIT measurements and CO transfer parameters. The mathematical model developed to adjust for the differences between the 2 measurements (R(2)=0.568; P<.001) was compensation factor=1.81# - 0.82# height (m)# -0.004 x KCO (%).
The measurement of breathing pattern by EIT in patients with COPD requires the use of a previously calculated calibration equation that incorporates not only individual anthropometric characteristics but gas exchange parameters as well.
采用电阻抗断层成像（EIT）技术测量慢性阻塞性肺疾病（COPD）患者的呼吸模式，需要使用一种数学校准模型，该模型不仅要纳入人体测量学特征（此前在健康个体中进行过评估），还可能要纳入与COPD相关的功能改变。本研究的目的是分析一组男性患者中EIT测量值与肺量计参数、静态肺容量和一氧化碳弥散量（DLCO）之间的关联，以建立一个将EIT信号转换为容积信号的校准方程。
我们测量了28例第一秒用力呼气容积（FEV₁）/用力肺活量（FVC）比值<70%的患者的用力肺活量（FVC）、一秒用力呼气容积（FEV₁）、FEV₁/FVC、残气量、肺总量、DLCO、一氧化碳转运系数（KCO）以及标准人体测量学参数。然后我们比较了来自一个先前经验证的EIT设备和一个标准呼吸流速计的潮气量测量值。
平均（标准差）肺功能结果为：FVC，72（16）%；FEV₁，43%（14）%；FEV₁/FVC，42%（9）%；残气量，161%（44）%；肺总量，112%（17）%；DLCO，58%（17）%；KCO，75%（25）%。呼吸流速计和EIT设备测量的平均（标准差）潮气量分别为0.697（0.181）L和0.515（0.223）L（P<0.001）。在EIT测量值与CO转运参数之间发现了显著关联。为校正这两种测量值之间的差异而建立的数学模型（R²=0.568；P<0.001）为：补偿因子=1.81# - 0.82#身高（米）# -0.004×KCO（%）。
在COPD患者中采用EIT测量呼吸模式需要使用先前计算的校准方程，该方程不仅要纳入个体人体测量学特征，还要纳入气体交换参数。
