Dadzie C, Simpser M, Lavietes M H
Chest. 1985 Sep;88(3):420-5. doi: 10.1378/chest.88.3.420.
We compared tidal volume (VT) measured from the integrated airflow signal of a pneumotachygraph (PNTG) in ten patients, seated comfortably, with airway obstruction to VT, recorded simultaneously, by three chest-wall volume-displacement methods: two-channel magnetometer, isovolume calibration (mag-isov); respiratory inductance plethysmograph, isovolume calibration (rip-isov); and, inductance plethysmograph, least squares calibration (rip-l sq). There was no difference between VT, measured without PNTG, with each of the methods. When mouthpiece, noseclips, PNTG, and finally, dead space were included in a breathing circuit, VT increased to approximately one and one-half times that measured without the mouthpiece. Inspiratory volumes were measured with similar error by each method (mag-isov, 8.61 +/- 5.73 percent SD; rip-isov, 9.30 +/- 6.12 percent SD; rip-l sq, 8.43 +/- 6.27 percent SD). We conclude that in airway obstruction patients seated in a constant position, over the range of inspiratory volumes studied, error associated with chest wall volume-displacement methods is no greater than in normal subjects.
我们比较了10例气道阻塞且坐姿舒适的患者，通过呼吸流速计（PNTG）的整合气流信号测得的潮气量（VT），与同时采用三种胸壁容积位移法记录的VT：双通道磁力计、等容积校准（磁 - 等容积法）；呼吸感应体积描记器、等容积校准（呼吸感应体积描记器 - 等容积法）；以及感应体积描记器、最小二乘法校准（呼吸感应体积描记器 - 最小二乘法）。在不使用PNTG的情况下，每种方法测得的VT之间没有差异。当呼吸回路中加入咬嘴、鼻夹、PNTG，最后再加入死腔时，VT增加到约为不使用咬嘴时测量值的1.5倍。每种方法测量吸气量的误差相似（磁 - 等容积法，标准差8.61±5.73%；呼吸感应体积描记器 - 等容积法，标准差9.30±6.12%；呼吸感应体积描记器 - 最小二乘法，标准差8.43±6.27%）。我们得出结论，在气道阻塞患者处于固定体位时，在所研究的吸气量范围内，与胸壁容积位移法相关的误差并不大于正常受试者。
