Development of a device for measuring tidal volume ambulatorily withouto calibration using optical fibers

虽然流量计能给出准确的潮汐量，但它需要戴上口罩，这会使受试者感到不舒服，甚至影响受试者的呼吸模式。使用流量计以外的任何方法进行测量必须由每个受试者的流量计校准。为了免除口罩和校准，我们开发了一种测量躯干容积变化的新方法，因为它确定了躯干容积变化等于肺容积变化。开发了一种使用光纤的曲率传感器，以获得躯干的横截面积。两个截面的形状由20个曲率传感器重建，以产生面积。另外两个截面积是根据面积和周长之间的关系估计出来的。四个横截面积和它们之间的三个距离给出了与呼吸有关的躯干体积。周长和距离是由长度传感器测量的，我们也利用光纤开发了长度传感器。用热线流量计测量了6例受试者的肺容量变化，同时用我们的方法测量了躯干的变化。两个测量值之间的变化呈线性关系，没有太多的散射，两者之间的回归线斜率在0.8 ~ 1.2之间。

Although a flowmeter gives accurate tidal volume, it requires a facemask which makes a subject uncomfortable and even affects breathing pattern in the subject. Measurements using any methods other than the flowmeter must be calibrated by the flowmeter in each subject. To dispense with the facemask and calibration, we developed a new method which measures the change in the body trunk volume, because it is established that the change in the body trunk is equal to that in the lung volume.A curvature sensor using an optical fiber was developed to yield a cross-sectional area of the body trunk. The shapes of two cross sections were reconstructed from 20 curvature sensors, to produce the area. Other two cross-sectional areas were estimated based on the relation between an area and a circumference length. The four cross-sectional areas and the three distances between them gave the body trunk volume related to respiration. Circumference lengths and distances were measured by length sensors which we also developed using optical fibers.The change in the lung volume was measured by a hot-wire flowmeter in six subjects, and the change in the body trunk was simultaneously measured by our method. The relation between two measured change was linear without much scattering, and the slope of the regression line between them ranged from 0.8 to 1.2.