JPH04253841A - Calibration type plethysmography measuring apparatus by cuff compression method - Google Patents

Abstract

PURPOSE:To achieve a measurement of plethysmography with a higher accuracy by pressing a measuring part by a cuff & bag pressure equivalent to a venous pressure using a pressure cuff & bag (pressing band) to measure a capacity in an artery blood vessel with a venous blood at the measuring part discharged. CONSTITUTION:When an light emitting diode (light source) 2, a phototransistor (photodetector) 3 and a pressure cuff & bag 1 are mounted by a finger's inputting, air is sent to a pressure cuff & bag 1 with an air compressor 7 to press a mounted part of the pressure cuff & bag 1 gradually. Then, when a cuff & bag pressure comes close to a venous pressure (20-30mmHg), the pressurization is stopped to make the vein flat. Then, the quantity of irradiation light control section emits light from a light source 2 to detect a light signal with a photo detector 3. The signal is sent to an amplification part and a filter 6 to amplify while being separated into AC and DC components. These signals undergo an A/D conversion with a processing section 4 and a plethysmography calibrated is calculated, displayed, recorded and preserved.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a calibrated volume pulse wave measuring device.

0002

[Prior Art] Conventional technology for calibrated volume pulse wave measurement involves installing a light source and a photodetector facing each other at the measurement site, and detecting changes in the amount of light transmitted through the site. The calibrated volume pulse wave was obtained by normalizing the alternating current component of the transmitted light amount by the direct current component of the transmitted light amount corresponding to the intravascular volume.

0003

[Problems to be Solved by the Invention] The conventional measurement method described above detects volume information of the arterial system by detecting changes in the amount of transmitted light, but strictly speaking, the influence of the venous system on the amount of transmitted light is also important. Not negligible, the detected volume information did not purely reflect volume changes in the arterial system. In other words, the DC component of the amount of transmitted light corresponding to the arterial intravascular volume of the relevant region is
Because it is greatly influenced by the venous system, the arterial intravascular volume appears to be large. The drawback of volume pulse waves is that they underestimate the value of the area that is actually being measured.

0004

[Means for Solving the Problems] The calibrated plethysmography device using the cuff compression method of the present invention includes a light source and a photodetector placed opposite to a human finger, and a cuff ( a first means for detecting changes in intravascular volume and volume pulse waves as changes in the amount of transmitted light using a compression band; It is comprised of a second means for detecting, and a third means for measuring a volume pulse wave calibrated from the volume information obtained by the second means.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be explained with reference to the drawings. FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention, and FIG. 2 is an external view showing the state of measurement with a human finger.

In FIG. 2, reference numeral 1 denotes a cuff (compression band) for compressing the measurement site, which is pneumatically controlled with respect to the human finger. Reference numeral 2 denotes a light source, which is composed of a light emitting diode. 3
is a photodetector composed of a phototransistor with high light receiving sensitivity for the emission wavelength of a light emitting diode. Then, as shown in FIG. 2, a light source and a photodetector are placed facing each other at the measurement site, and a compression cuff is attached from above.

Next, the operation of this embodiment will be explained using FIG. 1.

[0008] When the light source, photodetector, and cuff are properly attached, air is sent to the cuff by the air compressor 7, gradually compressing the area where the cuff is attached. Cuff pressure is venous pressure (2
0 to 30 mmHg), the pressurization is stopped, and with the vein applanated, the light from the light emitting diode 2 controlled by the irradiation light amount control unit 5 is detected and amplified by the photodetector (phototransistor) 3. (first means), and separates the signal into an alternating current component and a direct current component (second means). 4 is a data processing unit and a control unit for each unit, which A/D converts these signals using AC and DC components that are not affected by venous blood obtained as described above, and generates a calibrated volume pulse wave. Calculate, display, record, and save (third means).

[0009]

[Effects of the Invention] As explained above, the present invention compresses the measurement site with a cuff (compression band) with a cuff pressure equivalent to venous pressure.
Since the arterial intravascular volume at the measurement site can be measured while excluding venous blood at the measurement site, there is an effect that more accurate volume pulse wave measurement can be performed.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.

FIG. 2 is an external view showing the state of measurement using a human finger according to this embodiment.

[Explanation of symbols]

1 Compression cuff 2 Light source (light emitting diode) 3 Photodetector (phototransistor) 4
Processing section 5 Irradiation light amount control section 6 Amplification section and filter 7 Air compressor

Claims (1)

[Claims] [Claim 1] Changes in intravascular volume and volume pulse waves are detected as changes in the amount of transmitted light using a light source and a photodetector placed opposite the human hand and a cuff (compression band) for compressing the relevant area. a first means; a second means for detecting changes in intravascular volume and volume pulse waves from the first means without being affected by venous blood; and calibration from the volume information obtained from the second means. 1. A calibrated plethysmogram measuring device using a cuff compression method, characterized in that the device comprises a third means for measuring a plethysmographic plethysmogram.