CHANGES IN TIDAL VOLUME, FREQUENCY, AND VENTILATION INDUCED BY THIR MEASUREMENT
CHANGES IN TIDAL VOLUME, FREQUENCY, AND VENTILATION INDUCED BY THIR MEASUREMENT
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DOI：
10.1152/jappl.1972.33.2.252
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发表时间：
1972-01-01
影响因子：
3.3
通讯作者：
BRODSKY, J
中科院分区：
文献类型：
--
作者：
GILBERT, R;AUCHINCL.JH;BRODSKY, J
方法该方法最近已被详细描述（5），并基于Konno和Mead（6）开发的原理。胸壁和腹部的直线运动由磁线圈测量。将胸部运动接收器线圈放置在剑突上方的中线可变距离处，以提供最大偏转以实现安静呼吸;将腹部运动接收器线圈放置在脐上方5 cm的中线处。相应的励磁线圈被放置在背面相同的水平。交流电：发送到激励器线圈产生磁场，该磁场在接收器线圈中感应出与接收器线圈和激励器线圈之间的距离成反比的电压。来自胸部和腹部接收器线圈的信号以电子方式相加以给出代表潮气量的“总”信号。比例控制改变了胸部和腹部信号的相对放大，并进行了如下调整。线圈就位后，受试者通过肺活量计吸气和呼气;肺活量计钟的运动通过扭矩电位计转换为电信号。要求受试者进行两次呼吸，一次主要使用胸腔（胸部呼吸），另一次在吸气期间胸部运动被主动抑制而腹部突出（腹部呼吸）。在这两次呼吸过程中，三个信号同时记录在磁带上：来自胸部电极的信号，来自腹部电极的信号和来自肺活量计的信号。然后从磁带循环中重复播放这些信号，胸部和腹部信号通过比例控制器馈送，然后将它们组合起来以给出总信号。将总磁力计信号和肺活量计信号置于示波器的轴上;所得信号形成闭环。当磁带循环重复运行两次呼吸时，调整比率控制，直到代表两次呼吸的XY循环重叠。此时，比例因子得到最佳调整。最后，在一系列不同深度的呼吸期间，根据肺活量计信号校准总磁力计信号。如果胸式呼吸和腹式呼吸的正确叠加已经实现，磁力计相对于肺活量计的校准是线性的。
METHODSThe method has recently been described in detail (5) and is based on principles developed by Konno and Mead(6). Linear motion of the chest wall and abdomen was measured by magnetic coils. A receiver coil for chest motion was placed in the midline a variable distance above the xiphoid to give maximum deflection for quiet breathing; a receiver coil for abdomen motion was placed in the midline 5 cm above the umbilicus. Corresponding exciter coils were placed at the same level on the back. Alternating current: sent to the exciter coils produced a magnetic field which induced a voltage in the receiver coils inversely proportional to the distance between the receiver and exciter coils. The signals from the chest and abdomen receiver coils were added electronically to give a “total” signal, representing the tidal volume. A ratio control altered the relative amplification of chest and abdomen signals, and was adjusted as follows. With the coils in place, the subject breathed in and out of a spirometer; the motion of the spirometer bell was converted to an electrical signal by a torque potentiometer. The subject was asked to take two breaths, one using primarily the rib cage (the chest breath) and one where the chest motion was voluntarily inhibited while the abdomen was protruded during inspiration(the abdomen breath). During these two breaths, three signals were recorded simultaneously on a tape loop: the signal from the chest electrodes, the signal from the abdomen electrodes, and the signal from the spirometer. The signals were then played repeatedly from the tape loop with the chest and abdomen signals feeding through the ratio control before they were combined to give the total signal. The total magnetometer signal and the spirometer signal were put on the axes of an oscilloscope; the resulting signal formed a closed loop. As the tape loop ran the two breaths repeatedly, the ratio control was adjusted until the XY loops representing the two breaths were superimposed. At this point the scaling factors were optimally adjusted. Finally the total magnetometer signal was calibrated against the spirometer signal during a series of breaths of varying depth. If proper superimposition of the chest and abdomen breaths had been achieved, the calibration of the magnetometer against the spirometer was linear.