JPS602234A - Color concentration measuring apparatus - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [11 Technical Field] The present invention is a non-invasive method for measuring the concentration of a dye injected into the blood of a living body in order to measure blood circulation volume such as heart rate measurement using a dye dilution method. The present invention relates to a dye concentration measuring device for measuring.

[21 Prior Art and Its Problems The prior art will be explained by taking the measurement of cardiac output as an example. The principles and characteristics of this measurement method are explained in some publications (for example, "Clinical Application of Indicator Dilution Method", Chapter 4, pp. 67-68, co-authored by Nakamura, Katori, and Watanabe, published by Nakahaku Shoten). , will be briefly described below.

The method currently commonly used in clinical practice to measure cardiac output is the indicator dilution method. Indicator dilution methods can be divided into several types depending on the indicator used, but the two most commonly used are the thermodilution method and the dye dilution method.

The thermodilution method is a method that uses a liquid that is hotter or colder than body temperature as an indicator. Therefore, there is a problem that correction is necessary and it is difficult to improve accuracy. Another problem is that this method is an invasive measurement method using a catheter as described above.

The dye dilution method is a method that uses a dye as an indicator.
It can be divided into the cuvette method and the earpiece method depending on the method used to measure the blood concentration of the dye. The cuvette method measures dye concentration directly from blood that is continuously collected, so although it has good accuracy, it is an invasive measurement method. On the other hand, the earpiece method is a non-invasive measurement method that measures the blood pigment concentration by measuring the transmitted light in the earlobe.
Accuracy is low because it transcutaneously measures the pigment concentration in the blood vessels located quite deep below the skin surface of the earlobe.

Furthermore, it is necessary to stimulate blood circulation in the earlobe by some means before measurement, which is troublesome.

(3) Purpose of the Invention The present invention has been made in order to solve the obstacles between the above measurement methods and to measure cardiac output non-invasively, simply, and with high precision using the dye dilution method. It is.

For this purpose, the method is characterized by measuring the concentration of a single pigment transcutaneously on the oral mucosa using an optical method.

In the oral mucosa, the epithelium has no pigment and is highly transparent, so light can reach the lower layer where blood vessels are distributed (
, it is possible to perform highly accurate measurements.

(4) Contents of the invention Fig. 1 is a diagram illustrating the structure of the tip portion of the optical fiber sensor used in this measuring device, and Fig. 1 (1) is a sectional view thereof.1 in tζ in this figure is a sensor. This is the tip of 2.
is an optical fiber bundle, a part of which is used to irradiate the oral viscosity measurement light, and the rest is used to guide reflected and scattered light from the mucous membrane to the light receiving element. 3 is a 7-eye 2 bundle of optical fibers. In order to prevent blood circulation from being obstructed by unnecessarily compressing the oral mucosa, the surface 1asga of the sensor tip l on the side that comes into close contact with the mucous membrane is smooth as shown in Figure 1 (2). It is desirable that the surface be a continuous curved surface with a wide area.

FIG. 2 shows an example of the tank configuration of the entire measuring device. The sensor tip 1 is placed in the oral cavity, between the inner cheek viscosity 18, the gums 14 and the teeth 15, and the sensor surface la e 2
a is placed in close contact with the mucous membrane.

The optical fiber bundle 2 is branched into two light transmitting optical fiber bundles 4.5 and one light receiving optical fiber bundle 6 at the branching part 18. This branching can be done in an appropriate manner so that the reflected and scattered light from the mucous membrane can be received evenly over as wide a range as possible, such as by disposing the transmitting and receiving fibers at the opening end surface 2a of the 7-eye μ bundle so that the arrangement is random. It is desirable that this be done. 7a and 7b are light emitting elements (for example, laser diodes) having a wavelength of J'i4, which are coupled to the optical fiber bundle 4.5 for transmitting light, and whose light emitting outputs are controlled by driving circuits 8a and 8b. . These light emitting elements are alternately turned on and off by a control signal from the central tray section 11. The reflected and scattered light of the measurement light on the oral mucosa is guided to a light receiving element 9 (for example, a photo diode) by a light receiving optical fiber bundle 6. The signal from the light-receiving element 9 is amplified by the amplifier circuit lO, and then sent to the central processing unit 11.
sent to.

The central processing unit 11 separates this signal into intensity signals of reflected and scattered light for each of the measurement lights having wavelengths of 217], calculates the pigment concentration, and calculates the cardiac output using this value. A data display section 12 displays a dye concentration curve and other data (for example, cardiac output). From the reflected and scattered light intensity,
An outline of the principle for determining blood pigment concentration is described below.

If the measurement light is irradiated onto the oral mucosa and the intensity of the reflected and scattered light is measured, the intensity will decrease exponentially as the pigment concentration in the blood flowing through the blood vessels distributed in the submucosa increases. . Using this relationship, the blood pigment concentration can be estimated from changes in the intensity of reflected and scattered light. In addition, by selecting two wavelengths for the measurement light, one for which the absorbance changes significantly due to changes in dye concentration, and another for which the absorbance hardly changes, measuring the reflected and scattered light intensity for each, and taking the ratio. , changes in reflected and scattered light intensity other than those caused by changes in dye concentration can be offset.

Now, suppose that when the dye I(nv) is injected bilaterally into a vein, a dye dilution curve as shown in FIG. 3 is obtained. The first time this curve? 7! The area of the ring part is S (nV・
min// ), cardiac output Q (//min
) is determined by the following formula.

Q=I/S (//m1n) The configuration for using the present invention to measure cardiac output has been described above, but the dye concentration measuring device of the present invention is not limited to measuring cardiac output, but can also be used, for example. It can be used for tests that use burn second dyes, such as liver function tests.

(5) Effects of the Invention By using the pigment concentration measuring device of the present invention, it is possible to easily detect a good color (blood pigment concentration) by simply holding the tip of the optical fiber sensor in the subject's mouth without causing any invasive treatment to the subject. Concentration can be measured.

[Brief explanation of drawings]

Figure 1 shows an example of the girder structure at the tip of the optical 7-eye sensor used in this measuring device. (1) is its cross-sectional view, and (2) is (1) viewed from the left. This is a view. FIG. 2 is a diagram showing the order of magnitude of the entire measuring device. The 8th vA is a dilution curve showing the temporal change in dye concentration, and S is the area of the first circulation part. l... Optical fiber sensor tip body 1a... Optical fiber sensor tip body surface 2...
Optical fiber bundle for transmitting and receiving light 2a ... Optical fiber bundle for transmitting and receiving light end face 8 ... Outer cover of optical fiber bundle 4.5 ... Optical fiber bundle for transmitting light 6 ... Optical fiber for receiving light 7 a e 7 b...Light emitting element 8at8b...Light emitting element driving circuit 9...Light receiving element 10...Amplifying circuit 11...Central processing unit 12...Patent attorney representing the display department Satoshi Ushiro (f) Figure 1] Suboshibroom 3 eyes

Claims (1)

[Claims] This is a device that measures the concentration of pigment in the body, and it guides measurement light from a light-emitting element with 29 wavelengths that flashes alternately to the measurement site (
A first optical fiber is provided, and a second optical fiber is provided that guides the reflected and scattered light from the portion to the light receiving element, and the light signal received by the light receiving element is transmitted to the light receiving element at each wavelength included in the measurement light. A method for calculating the dye concentration from the intensity of the reflected and scattered light for each wavelength obtained, and a means for calculating the dye concentration from the intensity of the reflected and scattered light for each wavelength, and a means for calculating the dye concentration time change curve. A pigment concentration measuring device characterized in that it calculates cardiac output in comparison with.