JP2019198547A - Blood component measurement method, device and program - Google Patents

Abstract

To provide a technique capable of accurately measuring blood level of a blood component on the basis of light radiated to a living body such as a finger of a human being.SOLUTION: There is provided a blood component measurement device comprising: a measurement part for measuring a pulse wave signal on the basis of light which is radiated to a living body and then is reflected from the living body; a pulse rate acquisition part for acquiring a pulse rate of the living body in measurement time of the pulse wave signal;and a processing part for processing calculation of the blood level of a prescribed blood component on the basis of the measured pulse wave signal.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a blood component measurement method, a blood component measurement device, and a blood component measurement program.

  In addition to blood cells and water, blood contains various components such as proteins such as albumin and hemoglobin, neutral fat, cholesterol, and glucose, which reflect human health. Therefore, measurement of blood components is important in evaluating the human health condition, and analysis of blood collected using an injection needle is generally performed. However, due to factors such as pain from needle puncture, complexity from work after blood collection and disposal of the needle, and risk of infection, frequent blood analysis is not practical, so blood collection There is a need for a non-invasive method of measuring blood components that is not accompanied. Therefore, a method for calculating the blood concentration of a blood component by non-invasively acquiring a blood absorption spectrum and analyzing the spectrum shape has been studied.

  As a method of non-invasively measuring and calculating the absorption spectrum of blood, light is irradiated on a living body, and the intensity of light received from the living body is periodically changed by blood pulsation. By calculating the light absorbance of each wavelength from the change width of the light intensity obtained by subtracting the light intensity (for example, the maximum value and the minimum value), the light absorbance of each wavelength, that is, blood There is a method of calculating the absorption spectrum of the above (Patent Documents 1 and 2). Also, there is a method of measuring a biological lipid concentration in blood of a living body based on a light scattering coefficient when the living body is irradiated with continuous light (Patent Document 3).

Japanese Patent No. 3345481 International Publication No. 2003/079900 International Publication No. 2014/087825

  However, since the absorption spectrum of blood fluctuates due to the influence of blood pulsation at the time of measurement, the observed absorption spectrum of blood may not correctly reflect the blood concentration of the measurement target component in the above technique. There is a concern that the measurement accuracy of the blood concentration may be lowered by using such an absorption spectrum of blood.

  In view of the above situation, an object of the technology disclosed herein is to provide a technology for accurately measuring the blood concentration of a blood component from light irradiated on a living body such as a human finger.

  The blood component measurement device of the present disclosure includes a measurement unit that measures a pulse wave signal based on light received from a living body by irradiating light to the living body, and a pulse rate that acquires the pulse rate of the living body at the time of measuring the pulse wave signal An acquisition unit and a processing unit that processes the calculation of the blood concentration of a predetermined blood component from the measured pulse wave signal based on the acquired pulse rate. Thereby, when calculating the blood concentration of a desired blood component from the light received from the living body, it is possible to suitably prevent the blood concentration calculation accuracy from being lowered due to the pulse rate of the living body.

  In the above blood component measurement device, the pulse rate acquisition unit may calculate the pulse rate of the living body from the measured pulse wave signal. Further, in the blood component measuring apparatus, the processing unit does not output the blood concentration of a predetermined blood component when there is no pulse rate acquired within an allowable range determined by a reference pulse rate related to a living body. You may comprise as follows. Moreover, the pulse rate used as the reference | standard regarding a biological body is an average value of the pulse rate of a biological body, and the tolerance | permissible_range may be 95%-110% of the average value of the pulse rate of a biological body.

  In the blood component measuring apparatus, the processing unit may correct the blood concentration of a predetermined blood component based on the acquired pulse rate. The blood component measurement apparatus further includes an absorption spectrum calculation unit that calculates an absorption spectrum of biological blood from a pulse wave signal, and a blood concentration that calculates a blood concentration of a predetermined blood component from the absorbance indicated by the calculated absorption spectrum. A concentration calculation unit, and a pulse rate ratio calculation unit that calculates a ratio of the acquired pulse rate to a reference pulse rate related to the living body, and the processing unit calculates the absorbance indicated by the calculated absorption spectrum. The absorbance may be corrected by dividing by. The blood component measuring device further includes a pulse rate ratio calculating unit that calculates a ratio of the acquired pulse rate to a reference pulse rate related to a living body, and a ratio of the pulse rate and a blood concentration of a predetermined blood component. A conversion unit that converts the calculated ratio into an error using a calibration curve that indicates a correlation with the calculation error, and the processing unit is converted from the blood concentration of a predetermined blood component calculated from the pulse wave signal. The error may be subtracted. The blood component measuring apparatus further includes an absorption spectrum calculation unit that calculates an absorption spectrum of blood of a living body from a pulse wave signal, and a pulse rate that calculates a ratio of the acquired pulse rate to a reference pulse rate related to the living body A ratio calculation unit, and the processing unit may calculate the blood concentration of a predetermined blood component by applying the absorbance indicated by the calculated absorption spectrum and the calculated ratio to a predetermined regression equation. .

  Further, the blood component measurement method disclosed herein is obtained by measuring a pulse wave signal based on light received from a living body by irradiating the living body with light, and acquiring a pulse rate of the living body at the time of measuring the pulse wave signal. Based on the measured pulse rate, the calculation of the blood concentration of a predetermined blood component from the measured pulse wave signal is processed.

  In the blood component measurement method described above, obtaining the pulse rate of the living body may include calculating the pulse rate of the living body from the measured pulse wave signal. In the blood component measurement method, the calculation of the blood concentration of the predetermined blood component is performed when there is no pulse rate acquired within an allowable range determined by a reference pulse rate related to a living body. The output of the blood concentration of a predetermined blood component may not be performed. Moreover, the pulse rate used as the reference | standard regarding a biological body is an average value of the pulse rate of a biological body, and the tolerance | permissible_range may be 95%-110% of the average value of the pulse rate of a biological body.

Further, in the above blood component measurement method, processing the calculation of the blood concentration of the predetermined blood component includes correcting the blood concentration of the predetermined blood component based on the acquired pulse rate. But you can. The above blood component measurement method further calculates a blood absorption spectrum of the living body from the pulse wave signal, calculates a blood concentration of a predetermined blood component from the absorbance indicated by the calculated absorption spectrum, and serves as a reference pulse for the living body. To calculate the ratio of the acquired pulse rate to the number and correct the blood concentration of the given blood component, the absorbance is calculated by dividing the absorbance indicated by the calculated absorption spectrum by the calculated ratio. May include. In addition, the blood component measurement method described above further calculates a ratio of the acquired pulse rate to a reference pulse rate related to a living body, and correlates the ratio between the pulse rate and the calculation error of the blood concentration of a predetermined blood component. Using the calibration curve shown, the calculated ratio is converted into an error, and the blood concentration of the predetermined blood component is corrected from the blood concentration of the predetermined blood component calculated from the pulse wave signal. Subtracting the generated error. The blood component measurement method further calculates a blood absorption spectrum of the living body from the pulse wave signal, calculates a ratio of the acquired pulse rate to a reference pulse rate related to the living body, and the predetermined blood component described above The correction of the blood concentration of the blood flow may include calculating the blood concentration of a predetermined blood component by applying the absorbance indicated by the calculated absorption spectrum and the calculated ratio to a predetermined regression equation. Good.

  Furthermore, the blood component measurement program of the present disclosure causes a computer to measure a pulse wave signal based on light received from the living body by irradiating light to the living body, and to acquire the pulse rate of the living body at the time of measuring the pulse wave signal. Based on the acquired pulse rate, the calculation of the blood concentration of a predetermined blood component from the measured pulse wave signal is processed.

  In the above blood component measurement program, obtaining the pulse rate of the living body may include calculating the pulse rate of the living body from the measured pulse wave signal. In the blood component measurement program, the calculation of the blood concentration of the predetermined blood component is performed when there is no pulse rate acquired within an allowable range determined by a reference pulse rate related to a living body. The output of the blood concentration of a predetermined blood component may not be performed. Moreover, the pulse rate used as the reference | standard regarding a biological body is an average value of the pulse rate of a biological body, and the tolerance | permissible_range may be 95%-110% of the average value of the pulse rate of a biological body.

  In the blood component measurement program, processing the blood concentration of the predetermined blood component includes correcting the blood concentration of the predetermined blood component based on the acquired pulse rate. But you can. The above blood component measurement program further causes the computer to calculate the absorption spectrum of the blood of the living body from the pulse wave signal, calculates the blood concentration of the predetermined blood component from the absorbance indicated by the calculated absorption spectrum, and To calculate the ratio of the acquired pulse rate to the pulse rate to be corrected, and to correct the blood concentration of the predetermined blood component, the absorbance indicated by the calculated absorption spectrum is divided by the calculated ratio. It may also include correcting the absorbance. The blood component measurement program further causes the computer to calculate the ratio of the acquired pulse rate to the reference pulse rate related to the living body, and to calculate the error in the ratio of the pulse rate and the blood concentration of the predetermined blood component. Using the calibration curve showing the correlation of the above, the calculated ratio is converted into an error, and the blood concentration of the predetermined blood component is corrected in the blood of the predetermined blood component calculated from the pulse wave signal. Subtracting the converted error from the concentration may also be included. The blood component measurement program further causes the computer to calculate the absorption spectrum of the blood of the living body from the pulse wave signal, to calculate the ratio of the acquired pulse rate to the reference pulse rate related to the living body, To correct the blood concentration of the blood component of the blood flow, it is possible to calculate the blood concentration of the predetermined blood component by fitting the absorbance indicated by the calculated absorption spectrum and the calculated ratio to a predetermined regression equation. May be included.

  According to the technique disclosed herein, it is possible to provide a technique for accurately measuring the blood concentration of a blood component from light irradiated on a living body such as a human finger.

It is a figure which shows an example of a structure of the blood component measuring apparatus in one Embodiment. It is a figure which shows typically the blood component measuring device in one Embodiment. It is a figure showing typically some blood component measuring devices in one embodiment. It is a figure which shows an example of the flowchart of the process performed by the blood component measuring device in one Embodiment. It is a graph which shows an example of the pulse wave signal measured by the blood component measuring device in one embodiment. It is a figure which shows the outline of the noise removal process by the blood component measuring device in one Embodiment. It is a graph which shows an example of the absorption spectrum measured by the blood component measuring device in one embodiment. It is a figure which shows an example of the measurement result by the blood component measuring device in one Embodiment. It is a graph which shows the correlation with the blood TG value based on the measurement result of FIG. 8, and noninvasive blood absorbance. It is a graph which shows the blood TG value and TG estimated value based on the measurement result of FIG. It is another graph which shows the blood TG value and TG estimated value based on the measurement result of FIG. FIG. 6 is a diagram illustrating an example of a subroutine executed by the blood component measurement device according to the first embodiment. It is a graph which shows the correlation with the pulse rate ratio in Example 1, and the error of the TG estimated value with respect to the blood TG value. 3 is a graph showing blood TG values and estimated TG values in Example 1. FIG. 6 is another graph showing blood TG values and estimated TG values in Example 1. FIG. 6 is a graph showing a mean square error of an estimated TG value in Example 1. 6 is another graph showing the mean square error of the estimated TG value in Example 1. FIG. 10 is a diagram illustrating an example of a subroutine executed by the blood component measurement device according to the second embodiment. It is a table | surface which shows the non-invasive blood light-absorption corrected in Example 2, and the calculated TG estimated value. It is a graph which shows the correlation with the blood TG value in Example 2, and the corrected non-invasive blood light absorbency. 6 is a graph showing blood TG values and estimated TG values in Example 2. 10 is another graph showing blood TG values and estimated TG values in Example 2. FIG. 10 is a diagram illustrating an example of a subroutine executed by the blood component measurement device according to the third embodiment. 10 is a table showing an error amount of blood TG value estimation error and a corrected TG estimated value in Example 3. 10 is a graph showing blood TG values and estimated TG values in Example 3. 10 is another graph showing blood TG values and estimated TG values in Example 3. FIG. 10 is a diagram illustrating an example of a subroutine executed by the blood component measurement device according to the fourth embodiment. It is a table | surface which shows the value obtained by normalizing the non-invasive blood light absorbency and pulse rate ratio in Example 4, and a TG estimated value. It is a graph which shows the blood TG value and TG estimated value in Example 4. 10 is another graph showing blood TG values and estimated TG values in Example 4.

  Embodiments of the present invention will be described below with reference to the drawings. Note that the calculation target of the blood absorption spectrum in the present embodiment may be a site where blood pulsation occurs, and is preferably a finger, a toe, a palm, a sole, an earlobe, a lip, and the like. In particular, the index finger is preferred.

For example, the intensity of light transmitted through a human finger periodically varies due to blood pulsation inside the finger. In the present embodiment, blood absorbance at a plurality of wavelengths, that is, blood absorption spectra, is calculated noninvasively using a pulse wave signal that is a temporal change in light transmitted through a human finger. On the other hand, triglyceride (TG) in blood causes blood turbidity when its concentration increases, and thus increases the absorbance of blood. Therefore, the present embodiment provides a blood component measurement method for calculating a blood TG value indicating the blood concentration of TG, using as an index the blood absorbance (blood absorbance) when the living body is measured noninvasively. In particular, in the present embodiment, when calculating the blood TG value from the blood absorbance, the pulse rate is calculated from the pulse wave signal obtained at the time of measurement, and the calculation of the blood TG value is processed according to the pulse rate. Improved measurement accuracy of blood concentration of TG. The details of the blood TG value calculation process according to the pulse rate will be described later.

  First, a method for noninvasively measuring the absorption spectrum of blood in the present embodiment will be described. FIG. 1 shows an example of a schematic configuration of a blood component measuring apparatus 1 as an example of a computer in the present embodiment. The blood component measuring apparatus 1 irradiates a part (such as a finger) of a body of a subject including blood whose absorption spectrum is to be calculated with near infrared light, and calculates an absorption spectrum of blood based on the transmitted light spectrum. . As shown in FIG. 1, the blood component measurement device 1 includes a control unit 10, a storage unit 20, an irradiation unit 30, a light receiving unit 40, and a display unit 50.

The control unit 10 includes a Central Processing Unit (CPU), and controls the operation of each unit in the blood component measurement apparatus 1. The storage unit 20 stores a blood component measurement program for executing various processes in the blood component measurement apparatus 1 described below. In addition, the storage unit 20 stores data obtained when various processes in the blood component measurement apparatus 1 are executed. The control unit 10 executes various processes in the blood component measurement apparatus 1 by developing and executing the program stored in the storage unit 20 in a random access memory (RAM; not shown) in the apparatus. The irradiation unit 30 irradiates a part of a body (such as a finger) of a subject including blood, which is a target for calculating a blood absorption spectrum, with near infrared light. The transmitted light that has passed through the body of the subject is received by the light receiving unit 40. In the present embodiment, near infrared light is irradiated to the subject's finger by the irradiation unit 30, the irradiated light is transmitted through the finger, and the transmitted light is received by the light receiving unit 40. The spectroscope of the light receiving unit 40 measures the spectral spectrum of the transmitted light of the human finger over time.

  In the present embodiment, as an example, a multichannel Fourier transform type spectrometer is used as the spectrometer of the light receiving unit 40, and measurement is performed for 10 seconds (200 times at 50 msec intervals) by the spectrometer. The multi-channel Fourier transform spectrometer separated the incident light with a Savart plate, and acquired the interference fringes (interferogram) resulting from interfering the separated lights using a Fourier lens with a line sensor. A spectrum is obtained by Fourier transforming the interferogram. The wavelength range that can be measured by the multichannel Fourier transform spectrometer covers the entire near infrared region (900 to 2500 nm). Measure the transmitted light spectrum of the specimen using a multichannel Fourier transform spectrometer, and obtain the absorption spectrum of the specimen against the blank by comparing the so-called blank transmitted light spectrum acquired in advance with the measured transmitted light spectrum. Can do.

The control unit 10 includes a measurement unit 11, an absorption spectrum calculation unit 12, an absorbance calculation unit 13, a blood concentration calculation unit 14, a pulse rate acquisition unit 15, and a pulse rate ratio calculation unit as part of the function of the control unit 10. 16, a conversion unit 17, and a processing unit 18. The measuring unit 11 measures a pulse wave signal based on the transmitted light received by the light receiving unit 40. The absorption spectrum calculation unit 12 calculates the absorption spectrum of the subject's blood from the pulse wave signal. Specifically, the absorption spectrum calculation unit 12 removes noise from the pulse wave signal measured by the measurement unit 11 and calculates the absorption spectrum of the blood of the subject. The absorbance calculation unit 13 calculates the absorbance indicated by the absorption spectrum of TG, which is an example of a predetermined blood component, from the calculated absorption spectrum. The blood concentration calculation unit 14 calculates the blood concentration of TG from the calculated absorbance. The pulse rate acquisition unit 15 acquires the pulse rate of the subject at the time of measurement, for example, by calculating the pulse rate of the subject from the measured pulse wave signal. The method for acquiring the pulse rate of the subject at the time of measurement is not limited to the method using the pulse wave signal, and may be a method for acquiring the pulse rate from the subject by a separate method such as using a sensor such as a pulse meter. . The pulse rate ratio calculation unit 16 uses the subject's normal pulse rate (hereinafter referred to as “normal pulse rate”) as a reference pulse rate, and the ratio of the pulse rate during measurement to the normal pulse rate (hereinafter, referred to as “normal pulse rate”). (Referred to as “pulse rate ratio”). The conversion unit 17 converts the pulse rate ratio into an error using a calibration curve indicating the correlation between the pulse rate ratio and the calculation error of the blood concentration of TG. The processing unit 18 performs a blood concentration calculation process based on the acquired pulse rate. Specific processing of each unit will be described later. The calculation result of the blood concentration of the blood component by the control unit 10 is displayed on the display unit 50 as the estimated blood TG value.

  FIG. 2 schematically shows an example of the blood component measuring apparatus 1 in the present embodiment. The blood component measuring apparatus 1 is provided with an opening 60 for the subject to insert the finger 100. An irradiation unit 30 and a light receiving unit 40 are provided at the back of the opening 60. FIG. 3 schematically shows a state when the subject inserts the finger 100 into the opening 60 in the blood component measurement apparatus 1 of FIG. The irradiation unit 30 and the light receiving unit 40 are arranged so as to sandwich the subject's finger 100 inserted through the opening 60.

  The irradiation unit 30 includes a halogen lamp 31. As an example, the wavelength of light irradiated by the halogen lamp 31 is near infrared light in a wavelength range of 900 to 1700 nm. However, the type, number, and irradiation wavelength of the light source provided in the irradiation unit 30 are not limited to this. The light source may be, for example, a light-emitting diode (LED). The light receiving unit 40 includes a photodetector 41. Thereby, the near infrared light irradiated to the finger | toe 100 from the irradiation part 30 permeate | transmits the finger | toe 100 and is received by the light-receiving part 40. FIG. In the blood component measuring apparatus 1, the absorption spectrum of the subject's blood is calculated by the process described below based on the near infrared light received by the light receiving unit 40, and the blood TG value is measured. The measured blood TG value is displayed on the display unit 50.

  FIG. 4 shows an example of a flowchart of processing executed by the control unit 10. The control part 10 starts the process of the flowchart shown in FIG. 4 according to operation of the user of the blood component measuring apparatus 1, for example.

  In OP101, the control unit 10 controls the irradiation unit 30 to irradiate the subject's finger with near infrared light. The irradiated near-infrared light passes through the subject's finger and enters the light receiving unit 40 as transmitted light. Next, the process proceeds to OP102. In OP <b> 102, the control unit 10 measures the pulse wave signal using the transmitted light received by the light receiving unit 40 by the measuring unit 11.

  Next, in OP103, the control unit 10 removes noise from the pulse wave signal measured in OP102. FIG. 5 is an example of a graph showing changes over time of the pulse wave signal obtained in the present embodiment, with the axes of wavelength, light quantity, and time being set. As shown in FIG. 5, a pulse wave signal that is a change with time in the amount of transmitted light at each wavelength is obtained by measurement in OP102. In the pulse wave signal, in addition to fluctuations caused by blood pulsations, low-frequency drift fluctuations caused by the breathing of the human being to be measured and finger movements, and high-frequency noises caused by noise in the sensor in the blood component measuring apparatus 1 Is included. Therefore, the control unit 10 extracts changes caused by pulsation from the spectrum of transmitted light observed by performing various noise processes.

  FIG. 6 schematically shows an example of processing for removing low-frequency drift fluctuations and high-frequency noise from the spectral spectrum of transmitted light in OP103. In the figure, the horizontal axis of each graph represents time (seconds), and the vertical axis represents the amount of transmitted light (wavelength 1200 nm). As illustrated in FIG. 6, the control unit 10 performs a process of subtracting a sixth-order polynomial by fitting to remove low-frequency drift, and multi-variate the pulse wave signal of each wavelength to remove high-frequency noise. Principal component analysis is performed as time series data, and processing for reconstructing data using the first principal component is executed. The control unit 10 obtains a pulse wave signal from which noise has been removed as illustrated in FIG. 6 by performing these noise removal processes. Next, the control unit 10 advances the process to OP104.

In OP104, the control unit 10 calculates the absorption spectrum of blood based on the pulse wave signal from which the noise obtained in OP103 is removed by the absorption spectrum calculation unit 12.
In the present embodiment, the time average value of the amount of transmitted light at a wavelength λ of observed transmitted light and P _ave, the standard deviation corresponding to the amplitude of the pulse wave signal from which the noise is removed when the P _sd, at a wavelength λ Blood absorbance (blood absorption spectrum) A _Blood (λ) is calculated by the following equation (1).

That is, the absorbance of blood is calculated from the transmitted light amount (P _ave −P _sd ) after the blood volume has increased with reference to the transmitted light amount (P _ave + P _sd ) before the blood volume on the optical path increases due to pulsation. .

  After calculating the absorption spectrum of blood, the control unit 10 calculates the absorbance indicated by the absorption spectrum of TG by the absorbance calculation unit 13 in OP105, and calculates the absorbance calculated by the blood concentration calculation unit 14 using the calibration curve. The blood TG value of TG is calculated by converting into the blood concentration, and the calculated blood TG value is used as the measurement value. Details of specific processing will be described in each embodiment described later. Further, the control unit 10 displays the measured blood TG value on the display unit 50 in OP106, and ends the processing of this flowchart.

Here, FIG. 7 shows an example of an absorption spectrum of blood calculated by the above processing. FIG. 7 also shows an absorption spectrum measured when the blood is sealed in a quartz cell having an optical path length of 0.1 mm. In addition, about any absorption spectrum, normalization by the standard normal variable (Standard Normal Variate: SNV) is performed in the wavelength range of 1000-1350 nm. The horizontal axis of the graph of FIG. 7 indicates the wavelength (nm), and the vertical axis indicates the absorbance normalized by SNV. As can be seen from FIG. 7, both absorption spectra show similar shapes in which the absorbance is large at the short wavelength (near 1000 nm) side and the absorbance is small near the wavelength of 1250 to 1300 nm. That is, it can be said that this indicates that the absorption spectrum can be suitably measured by the blood absorption spectrum measurement process of the present embodiment.

  In the present embodiment, the blood TG value is calculated using the measurement of the absorption spectrum of blood. As described above, when the concentration of TG in blood increases, the turbidity of blood also increases. In general, when the turbidity of blood increases, the absorbance on the short wavelength side (around 1000 nm wavelength) in the blood absorption spectrum increases. Therefore, in the present embodiment, the blood component measurement apparatus 1 uses an absorption spectrum obtained by performing base correction so that the absorbance at a wavelength of 1200 nm is zero with respect to the absorption spectrum of blood measured noninvasively (hereinafter, “ Absorbance at a wavelength of 1000 nm (hereinafter referred to as “noninvasive blood absorbance”) in the “noninvasive blood spectrum”) is used as an index of the blood TG value to be calculated. Further, in the present embodiment, as an example, by using a regression line prepared in advance as a calibration curve for a correlation between a blood TG value obtained by blood sampling measurement described later and non-invasive blood absorbance, absorption of measured blood is measured. The non-invasive blood absorbance in the spectrum is converted into the blood TG value. The data of the calibration curve is stored in advance in the storage unit 20, for example.

Examples 1 to 4 relating to blood TG value calculation processing will be described below. In the following embodiments, components and processes similar to those described above will be described using the same reference numerals. First, the process of the control part 10 of the blood component measuring device 1 which is a premise in each embodiment will be described. In the processing of OP102 to OP104, the control unit 10 performs measurement of the pulse wave signal a plurality of times, and calculates the average value of the blood absorption spectrum calculated from each pulse wave signal as the blood absorption spectrum in the following processing. Used as

  The control unit 10 calculates the noninvasive blood absorbance from the blood absorption spectrum calculated in OP104. Furthermore, the control unit 10 converts the calculated noninvasive blood absorbance into a blood TG value using a calibration curve stored in the storage unit 20, and the blood TG value obtained by the conversion is measured. And

  FIG. 8 shows an example of the blood TG value measured by the above processing. Here, the above blood TG is measured using the blood component measuring apparatus 1 for four subjects five times a day (9:30, 11:30, 13:30, 15:30, 17:00). Execute value measurement processing. Furthermore, the blood TG value is measured by blood sampling (hereinafter referred to as blood sampling measurement) for the same subject. As an example, the blood component measurement apparatus 1 performs measurement by irradiating light on the left index finger of the subject. On the other hand, blood measurement is performed by puncturing the index finger or middle finger of the right hand with a lancet and bleeding, and measuring the blood TG value using a simple blood analyzer cobas b101 (Roche Diagnostics).

  In FIG. 8, each value of “ID_measurement number” is a combination of the identification number of each subject and each measurement time of the above five measurements. For example, “ID02_5” corresponds to the case where the subject whose identification number is “ID02” performs the measurement at the fifth time, that is, 17:00. Each value of “blood TG value” in the figure is a blood TG value measured by the blood sampling measurement. Each value of “non-invasive blood absorbance” in the figure is a value of non-invasive blood absorbance calculated by the control unit 10. Further, “TG estimated value” in the figure is an estimated value of the blood TG value calculated by the control unit 10. Each value of “error” in the figure is a value obtained by subtracting the value of “blood TG value” from the value of “TG estimated value”, and indicates the difference between the values.

  FIG. 9 is a graph showing the correlation between “blood TG value” and “non-invasive blood absorbance” in FIG. The horizontal axis of the graph of FIG. 9 indicates the blood TG value (mg / dL) by blood sampling measurement, and the vertical axis indicates the value of noninvasive blood absorbance. As can be seen from FIG. 9, there is a tendency that the “non-invasive blood absorbance” increases as the “blood TG value” increases. The correlation coefficient between “blood TG value” and “non-invasive blood absorbance” in FIG. 9 is 0.499.

FIG. 10 is a graph showing “blood TG value” and “TG estimated value” for each “ID_measurement number” in FIG. FIG. 11 is a graph showing the correlation between the “blood TG value” and the “TG estimated value” in FIG. The horizontal axis of the graph of FIG. 10 indicates each “ID_measurement number”, and the vertical axis indicates the estimated TG value (mg / dL). The horizontal axis of the graph of FIG. 11 indicates the blood TG value (mg / dL) by blood sampling measurement, and the vertical axis indicates the estimated TG value (mg / dL). Furthermore, when the mean square error is obtained as an index indicating the accuracy of the blood TG value calculated in OP105 using the following equation (2), it is “68 mg / dL”.

Note that i is a value when “ID_measurement number” in FIG. 8 is counted in order from the top. For example, the values of i corresponding to ID01_1 to ID01_5 are 1 to 5, respectively, and the values of i corresponding to ID02_1 to ID02_5 are 6 to 10, respectively. N is the number of measurements. In the case of FIG. Further, PredTG _i is the value of "TG estimate" in the i-th measurement, BloodTG _i is the value of the "blood TG value" in the i-th measurement.

  From the above description, in each of the following examples using the blood component measuring apparatus 1, the calculated non-invasive blood absorbance can be used as a useful index in estimating the blood TG value. An improvement in estimation accuracy can be expected.

  In each of the following examples, attention is paid to the pulse rate of the subject at the time of measurement. In general, the pulse rate can be easily measured by using, for example, a pulse meter, sensing and counting a pulse by finger pressure, or using a program of a smartphone. Therefore, the subject can easily grasp the normal pulse rate in advance or later.

  Therefore, in each of the following embodiments, the control unit 10 performs measurement of the pulse wave signal a plurality of times in the processing of OP102 to OP104, and the pulse rate at the time of measurement (hereinafter referred to as “measurement pulse rate”) from each pulse wave signal. Is calculated). The pulse rate at the time of measurement is, for example, the peak frequency of a frequency spectrum obtained by performing fast Fourier transform (FFT) on the pulse wave signal. The calculation of the pulse rate during measurement may be performed by another known method using a pulse wave signal. Then, the control unit 10 calculates the blood TG value using the average value of the noninvasive blood absorbance calculated from each pulse wave signal and the average value of the pulse rate at the time of measurement. Each value of “normal pulse rate” in the table shown in FIG. 8 is an average value obtained by removing the maximum value and the minimum value from the measured pulse rate at each measurement time. Further, each value of “pulse rate ratio” in the table shown in FIG. 8 is a value of the ratio of the pulse rate at the time of measurement to the pulse rate at normal time in each measurement time. Further, in each of the following examples, the normal pulse rate data of the subject is stored in the storage unit 20 in advance.

Example 1
FIG. 12 illustrates an example of subroutine processing executed by the control unit 10 in OP105 in the first embodiment. In the figure, “1” is connected to “1” in FIG. In this embodiment, in OP201, the control unit 10 calculates a pulse rate ratio in the current measurement time. Next, in OP202, the control unit 10 determines whether the value of the pulse rate ratio calculated in OP201 is in the range of 0.95 to 1.1, that is, in the range of 95% to 110% of the average value of the pulse rate. Determine whether or not. In addition, the range of 95% to 110% of the average value of the pulse rate is an example of an allowable range determined by the reference pulse rate related to the living body. When the value of the pulse rate ratio is within the range of 0.95 to 1.1 (OP202: Yes), the control unit 10 advances the process to OP203. On the other hand, when the value of the pulse rate ratio is not within the range of 0.95 to 1.1 (OP202: No), the control unit 10 advances the process to OP204.

  In OP203, the control unit 10 converts the non-invasive blood absorbance in the current measurement round into a blood TG value using a calibration curve, and calculates the converted value as a TG estimated value. When the calculation of the estimated TG value is completed, the control unit 10 ends the process of this subroutine and advances the process to OP106.

Here, FIG. 13 shows an error (TG estimated value−blood TG value) between the estimated TG value and the blood TG value obtained by the blood sampling measurement in the case of the table shown in FIG. The plotted graph is shown. In the graph of FIG. 13, the horizontal axis represents the pulse rate ratio, and the vertical axis represents the error (mg / dL) between the estimated TG value and the blood TG value obtained by the blood sampling measurement. As shown in FIG. 13, the error is small when the pulse rate ratio is near 1.0, and the error tends to increase as the pulse rate ratio is larger than 1.0 or smaller than 1.0. Understand. It can be said that this tendency of the pulse rate ratio indicates that when the blood TG value is calculated, it is desirable that the pulse rate of the subject at the time of measurement is closer to the normal pulse rate. That is, when the pulse rate of the subject at the time of measurement is different from the normal pulse rate, it can be said that the measurement accuracy may be improved by not performing the measurement. Therefore, in the present embodiment, the control unit 10 does not calculate the blood TG value when the pulse rate ratio is not within the range of 0.95 to 1.1 in each measurement time.

  In the case of the table shown in FIG. 8, the value of “ID_measurement number” is “ID01_2”, “ID01_3”, “ID01_5”, “ID02_2”, “ID02_3”, “ID03_3”, “ID03_4”, “ID04_1”, The pulse rate ratio in the measurement time “ID04_5” does not fall within the range of 0.95 to 1.1. Therefore, in this embodiment, the control unit 10 excludes these measurements. Specifically, in OP204, the control unit 10 does not execute the TG estimated value calculation process. As a result, the control unit 10 does not output the TG estimated value. And the control part 10 displays the measurement error which shows that calculation of the TG estimated value in the present measurement time is not performed on the display part 50. FIG. Here, examples of the measurement error include a message that informs the subject that the blood TG value cannot be accurately estimated because the pulse rate at the time of measurement deviates from the normal pulse rate of the subject. The content of is not limited to this. When the measurement error is displayed on the display unit 50, the control unit 10 ends the process of the flowchart of FIG.

  FIG. 14 is a graph showing the relationship between the estimated TG value at each measurement time and the blood TG value obtained by the blood sampling measurement in the case of the table shown in FIG. The horizontal axis of the graph of FIG. 14 indicates each “ID_measurement number”, and the vertical axis indicates the estimated TG value (mg / dL). In addition, since the estimated TG value is not calculated in the above measurement times where the pulse rate ratio is not within the range of 0.95 to 1.1, the estimated TG value and the blood TG value are not shown in the graph of FIG.

  FIG. 15 is a graph showing the correlation between the estimated TG value and the blood TG value obtained by the blood sampling measurement in the case of the table shown in FIG. The horizontal axis of the graph of FIG. 15 indicates the blood TG value (mg / dL) by blood sampling measurement, and the vertical axis indicates the estimated TG value (mg / dL). Compared with the graph shown in FIG. 11, it can be seen that the estimated TG value calculated in the present example is more consistent with the blood TG value obtained by the blood sampling measurement. In addition, according to the present example, the mean square error of the TG estimation value is “29 mg / dL”, and the pulse rate ratio is 0.95 to 1. .5 as in the above example described with reference to FIGS. It can be seen that the calculation accuracy of the estimated TG value is improved as compared with the mean square error “68 mg / dL” in the case where the estimated TG value is calculated at each measurement time regardless of whether it is within the range of 1. .

  Next, the range of pulse rate ratios that exclude measurement in this example will be examined. In the following description, in order to find an appropriate range of pulse rate ratios used for determining whether or not to calculate the estimated TG value, the range of pulse rate ratios excluding measurement is changed, The mean square error is calculated for the range of pulse rate ratios.

  First, in the case of the table shown in FIG. 8, a threshold value that is the upper limit of the pulse rate ratio range is provided, and when the pulse rate ratio is larger than the threshold value, the mean square error of the estimated TG value when the measurement is excluded is calculated. . In the case of the table shown in FIG. 16, when the threshold value that is the upper limit of the range of the pulse rate ratio is 1.0, 1.05, 1.1, 1.2, 1.3 in the case of the table shown in FIG. The mean square error of the TG estimated value calculated by the process of an Example is shown. The horizontal axis of the graph of FIG. 16 indicates a threshold value that is the upper limit of the pulse rate ratio range, and the vertical axis indicates the mean square error (mg / dL) of the TG estimated value. In each case, a threshold that is the lower limit of the pulse rate ratio range is not provided.

  As shown in the graph of FIG. 16, the estimated TG value is calculated when the threshold that is the upper limit of the range of the pulse rate ratio is 1.1 and measurement is excluded when the pulse rate ratio is greater than 1.1. It can be seen that the mean square error of is the smallest (36 mg / dL). That is, this result indicates that 1.1 is appropriate as the threshold value that is the upper limit of the range of the appropriate pulse rate ratio for determining whether or not to calculate the TG estimation value.

  Next, in the case of the table shown in FIG. 8, a threshold value is set as the lower limit of the pulse rate ratio range, and when the pulse rate ratio is smaller than the threshold value, the mean square error of the estimated TG value when the measurement is excluded is calculated. To do. 17, in the case of the table shown in FIG. 8, the threshold value that is the lower limit of the pulse rate ratio range is set to 0.9, 0.95, and 1.0, and is calculated by the processing of this embodiment. The mean square error of the estimated TG value is shown. The horizontal axis of the graph of FIG. 17 indicates a threshold value that is the lower limit of the pulse rate ratio range, and the vertical axis indicates the mean square error (mg / dL) of the TG estimated value. In each case, a threshold that is the upper limit of the pulse rate ratio range is not provided.

  As shown in the graph of FIG. 17, the estimated TG value is calculated when the threshold value which is the lower limit of the pulse rate ratio range is 0.95 and measurement is excluded when the pulse rate ratio is smaller than 0.95. It can be seen that the mean square error is the smallest (64 mg / dL). That is, this result shows that 0.95 is appropriate as the threshold value that is the lower limit of the range of the appropriate pulse rate ratio for determining whether or not to calculate the TG estimated value.

  As described above, the mean square error of the TG estimated value calculated when the range of the pulse rate ratio for determining whether to calculate the TG estimated value is 0.95 to 1.1. Is 29 mg / dL, the threshold value (1.1) that is the upper limit of the pulse rate ratio range and the threshold value (0.95) that is the lower limit of the pulse rate ratio range are used. Compared to excluding measurement, the measurement is excluded using the pulse rate ratio range determined by the upper threshold (1.1) and lower threshold (0.95). However, the mean square error is reduced. Therefore, in the present embodiment, it can be said that it is more preferable to adopt 0.95 to 1.1 as the range of the pulse rate ratio used for determining whether or not to calculate the TG estimated value. .

(Example 2)
FIG. 18 illustrates an example of subroutine processing executed by the control unit 10 in OP105 in the second embodiment. In this embodiment, in OP301, the control unit 10 calculates the pulse rate ratio in the current measurement time. Next, in OP302, the control unit 10 corrects the noninvasive blood absorbance by the pulse rate ratio calculated in OP301.

  Here, a non-invasive blood absorbance correction method using a pulse rate ratio for the purpose of improving the calculation accuracy of the estimated TG value in this embodiment will be described. As can be seen from FIG. 13, the error tends to increase positively as the pulse rate ratio is greater than 1, and the error tends to increase negatively as the pulse rate ratio is smaller than 1. Therefore, in this embodiment, the control unit 10 corrects the noninvasive blood absorbance by dividing the calculated noninvasive blood absorbance by the pulse rate ratio. Thereby, when the pulse rate ratio is larger than 1, the noninvasive blood absorbance is corrected to be smaller, and when the pulse rate ratio is smaller than 1, the noninvasive blood absorbance is corrected to be larger.

  In OP303, the control unit 10 converts the non-invasive blood absorbance corrected in OP302 into a blood TG value using a calibration curve, and calculates the converted value as a TG estimated value. When the calculation of the estimated TG value is completed, the control unit 10 ends the process of this subroutine and advances the process to OP106.

FIG. 19 shows the non-invasive blood absorbance corrected at each measurement time and the calculated TG estimated value in the case of the table shown in FIG. FIG. 20 shows the blood TG value obtained by blood sampling measurement at each measurement time and the corrected non-invasive blood absorbance in the case of the table shown in FIG. The horizontal axis of the graph of FIG. 20 shows the blood TG value (mg / dL) by blood sampling measurement, and the vertical axis shows the corrected non-invasive blood absorbance value. The corrected non-invasive blood absorbance is correlated with the blood TG value, and the correlation coefficient is 0.575. Therefore, compared with the correlation coefficient “0.499” between the non-invasive blood absorbance and the blood TG value when the non-invasive blood absorbance is not corrected, the non-invasive blood absorbance and blood corrected according to the present embodiment are compared. It can be seen that the correlation coefficient with the TG value increases.

  In this embodiment, a regression line is created in advance for the correlation between the blood TG value obtained by the blood sampling measurement shown in FIG. 20 and the corrected noninvasive blood absorbance. Then, using the created regression line as a calibration curve, the corrected non-invasive blood absorbance is converted into a blood TG value, and the converted blood TG value is set as a TG estimated value (“TG estimated value” in FIG. 19). . The calibration curve data is stored in advance in the storage unit 20. FIG. 21 is a graph showing the relationship between the blood TG value obtained by blood sampling measurement at each measurement time in the case of the table shown in FIG. 19 and the TG estimated value calculated by the processing of this example. FIG. 22 shows a graph in which the estimated TG value calculated by the processing of this example is plotted against the blood TG value obtained by the blood sampling measurement. The horizontal axis of the graph of FIG. 21 indicates each “ID_measurement number”, and the vertical axis indicates the estimated TG value (mg / dL). The horizontal axis of the graph of FIG. 22 indicates the blood TG value (mg / dL) by blood sampling measurement, and the vertical axis indicates the estimated TG value (mg / dL). The mean square error of the estimated TG value calculated by the processing of this embodiment is “56 mg / dL”, and no correction is performed, that is, the estimated TG value is calculated in all the measurement times in the case of the table shown in FIG. It can be seen that the calculation accuracy of the estimated TG value is improved compared to the mean square error “68 mg / dL”.

(Example 3)
FIG. 23 illustrates an example of subroutine processing executed by the control unit 10 in OP105 in the third embodiment. In this embodiment, in OP401, the control unit 10 converts the non-invasive blood absorbance obtained by the measurement into a blood TG value using a calibration curve stored in the storage unit 20, and the converted blood TG value is converted into the blood TG value. Calculated as a TG estimated value. Next, in OP402, the control unit 10 calculates a pulse rate ratio in the current measurement time.

  Here, a correction method for correcting the estimated TG value calculated in OP401 using the pulse rate ratio calculated in OP402 in this embodiment will be described. As can be seen from FIG. 13, a positive correlation is recognized between the pulse rate ratio and the estimation error of the blood TG value. Therefore, in this embodiment, for example, based on the past measurement results, a regression line is created in advance for the correlation between the pulse rate ratio and the estimation error of the blood TG value. It is used as a calibration curve to be converted into TG value estimation error. The calibration curve data is stored in advance in the storage unit 20, for example.

  In OP403, the control unit 10 converts the pulse rate ratio in the current measurement time into an estimation error of the blood TG value using the calibration curve stored in the storage unit 20. In OP404, the control unit 10 corrects the estimated TG value by subtracting the error converted in OP403 from the estimated TG value calculated in OP401. When the correction of the estimated TG value is completed, the control unit 10 ends the process of this subroutine and advances the process to OP106. In OP106, the control unit 10 displays the estimated TG value corrected in OP404 on the display unit 50.

24, in the case of the table shown in FIG. 8, the error amount of the estimation error of blood TG value calculated in each measurement time (“estimation error” in the figure) and the corrected TG estimation value (“correction” in the figure) Post TG estimate value "). FIG. 25 shows the blood TG value obtained by the blood sampling measurement at each measurement time and the TG estimated value corrected by the processing of this embodiment in the case of the table shown in FIG. FIG. 26 shows a graph in which corrected TG estimated values are plotted against blood TG values obtained by blood sampling measurement. The horizontal axis of the graph of FIG. 25 indicates each “ID_measurement number”, and the vertical axis indicates the estimated TG value (mg / dL). The horizontal axis of the graph of FIG. 26 indicates the blood TG value (mg / dL) by blood sampling measurement, and the vertical axis indicates the estimated TG value (mg / dL). The mean square error of the estimated TG value corrected by the processing of this embodiment is “46 mg / dL”, and correction is not performed. That is, the estimated TG value is calculated in all the measurement times in the case of the table shown in FIG. It can be seen that the calculation accuracy of the estimated TG value is improved compared to the mean square error “68 mg / dL”.

Example 4
FIG. 27 illustrates an example of subroutine processing executed by the control unit 10 in OP105 in the fourth embodiment. In this embodiment, in OP501, the control unit 10 calculates a pulse rate ratio in the current measurement time. Next, in OP502, the control unit 10 calculates a TG estimated value using the pulse rate ratio calculated in OP501.

  Here, calculation of the estimated TG value in the present embodiment will be described. The calculation of the estimated TG value by so-called single regression analysis for calculating the blood TG value only from the non-invasive blood absorbance is as described above. In this embodiment, the non-invasive blood absorbance and the pulse rate ratio are used as explanatory variables. The estimated TG value is calculated by multiple regression analysis. Specifically, for example, based on past measurements, a regression equation that relates the non-invasive blood absorbance and pulse rate ratio and the blood TG value is created in advance, and the non-invasive blood absorbance calculated by the processing of OP104 The estimated TG value is calculated by applying the pulse rate ratio calculated by the processing of OP501 to the regression equation. The regression equation data is stored in advance in the storage unit 20, for example.

Since the non-invasive blood absorbance and the pulse rate ratio are different variables in the regression equation, normalization is performed in the present embodiment so that each variable can be handled equally. Since multiple regression analysis and normalization methods are well-known techniques, detailed description thereof is omitted here. The regression equation shown in Equation (3) is obtained by normalizing the non-invasive blood absorbance and the pulse rate ratio with a so-called autoscale and performing multiple regression analysis using the non-invasive blood absorbance and the pulse rate ratio as explanatory variables. Equation (3) is an example of a predetermined regression equation.

Here, TG _i, .DELTA.A _i and P _i is the i-th measurement times respectively, TG estimate is a non-invasive blood absorbance and pulse rate ratio already autoscale.

  28, in the case of the table shown in FIG. 8, the values obtained by normalizing the non-invasive blood absorbance and the pulse rate ratio calculated at each measurement time by the autoscale (“autoscaled non-invasive blood absorbance in the figure”). ”,“ Autoscaled pulse rate ratio ”) and the TG estimated value calculated by the above equation (3). In the case of the table shown in FIG. 28, FIG. 29 shows the blood TG value obtained by the blood sampling measurement at each measurement time and the TG estimated value calculated by the processing of this example. FIG. 30 shows a graph in which the calculated estimated TG value is plotted against the blood TG value obtained by the blood sampling measurement. The horizontal axis of the graph of FIG. 29 represents each “ID_measurement number”, and the vertical axis represents the estimated TG value (mg / dL). The horizontal axis of the graph of FIG. 30 indicates the blood TG value (mg / dL) by blood sampling measurement, and the vertical axis indicates the estimated TG value (mg / dL). The mean square error of the estimated TG value calculated by the processing of the present embodiment is “30 mg / dL”, and the estimated TG value is calculated without using the regression equation in all measurement times in the case of the table shown in FIG. It can be seen that the calculation accuracy of the estimated TG value is improved compared to the mean square error “68 mg / dL”.

  Therefore, by calculating the TG estimated value using the pulse rate according to the above-described Examples 1 to 4, the error of the TG estimated value with respect to the blood concentration obtained by the blood sampling measurement, that is, the invasive measurement, is greater than that of the conventional technique. It can be expected that the calculation accuracy of the blood concentration of a desired blood component in non-invasive measurement of the absorption spectrum of blood will be improved.

  The above is the description of the present embodiment, but the configuration of the blood component measuring apparatus 1, the measurement process of the absorption spectrum, the estimation process of the blood TG value, and the like are not limited to the above-described embodiment. Various modifications can be made without departing from the technical idea of the invention.

  For example, in the first embodiment, the control unit 10 calculates the pulse rate ratio, and does not calculate the blood concentration when the calculated pulse rate ratio value is not within the allowable range. Instead of this, the control unit 10 does not calculate the pulse rate ratio, and sets a range including the normal pulse rate (for example, a range within 10 above and below the normal pulse rate) as an allowable range, and the pulse rate of the subject If the blood concentration is not within the allowable range, the blood concentration may not be calculated. In the first embodiment, when the blood concentration is not calculated, the control unit 10 does not calculate the TG estimated value and does not output the TG estimated value. Instead, the control unit 10 may calculate the TG estimated value, but may not output the TG estimated value by discarding the calculated TG estimated value.

  Further, in the above-described embodiment, the normal pulse rate data of the subject is stored in the storage unit 20 in advance, but when the subject repeats the measurement by the blood component measuring device 1, the control unit 10 displays the measurement result. Based on the normal pulse rate data of the subject stored in the storage unit 20, the data may be updated. Thereby, it can be expected that the calculation accuracy of the estimated TG value is further increased by further stabilizing the normal pulse rate value of the subject.

  In the present embodiment, the case where the blood concentration of triglyceride is measured by the blood component measuring device has been described as an example. However, the blood component whose blood concentration is measured by the blood component measuring apparatus of the present embodiment is not limited to triglyceride. The blood component measurement apparatus of this embodiment can also be applied to the measurement of blood concentrations of hemoglobin, glucose, cholesterol and the like.

  Moreover, in this embodiment, the light irradiated to the living body is monochromatic light having at least two wavelengths selected from a wavelength range of 400 to 2500 nm that passes through the living body. Note that the measurement may be performed by irradiating light in the entire wavelength range of 400 to 2500 nm or a part of the range, and spectroscopically measuring the received light into a plurality of wavelengths. The wavelength range of the light irradiated to the living body is more preferably 900 to 1700 nm, still more preferably 900 to 1300 nm. By selecting such a wavelength range, it is possible to measure a pulse wave signal that more accurately reflects the pulsation of blood in the living body, thereby making noise more effective by reconstruction based on the pulse wave signal in principal component analysis. Can be removed. The spectroscope preferably performs spectroscopic measurement of received light at intervals of 10 to 50 nm.

  The multi-wavelength time-series data of light measured in the present embodiment may be any of transmitted light intensity, reflected light intensity, scattered light intensity, or absorbance at the measurement site. That is, in the above description, it is assumed that the light receiving unit 40 receives transmitted light from a living body, but the light received by the light receiving unit 40 is not limited to transmitted light. By changing the number and position of the light receiving units 40, the transmitted light, reflected light, scattered light, or a plurality of types of light from the living body are received, and the above-described absorption spectrum measurement process is applied to the received light. can do. The pulse wave signal used for measuring the absorption spectrum is preferably an absorbance pulse wave signal, and more preferably a transmitted wave intensity and absorbance pulse wave signal. In addition, as a preprocessing method for optical signals of respective wavelengths when performing principal component analysis of multiwavelength time-series data, a centering process using a time average value is preferable. As a result, the center of fluctuations in light intensity and absorbance can be obtained.

In the present embodiment, when calculating the absorption spectrum of blood, an existing signal processing method may be used in combination in order to remove noise unnecessary for calculation from the pulse wave signal of received light. For example, before or after the principal component analysis based on this embodiment is performed, frequency filter processing that extracts only specific frequency components, and by fitting a polynomial to time-series data and making a difference, moderate low frequency drift is removed Processing, smoothing processing using a moving average or a Savitzky-Golay filter, or a combination thereof can be performed.

  In addition, the spectrometer used for measuring the absorption spectrum may be the multichannel Fourier transform spectrometer used in the present embodiment, for example, a single channel Fourier transform spectrometer, It may be a multichannel dispersive spectrometer or a single channel dispersive spectrometer.

DESCRIPTION OF SYMBOLS 1 Blood component measuring apparatus 10 Control part 11 Measurement part 12 Absorption spectrum calculation part 13 Absorbance calculation part 14 Blood concentration calculation part 15 Pulse rate acquisition part 16 Pulse rate ratio calculation part 17 Conversion part 18 Processing part 20 Storage part 30 Irradiation part 40 Light receiving unit 50 Display unit

The present invention is a blood component measurement method, blood component measurement device, and a blood component measurement program.

Claims (14)

A measurement unit that irradiates light on a living body and measures a pulse wave signal based on light received from the living body;
A pulse rate acquisition unit for acquiring the pulse rate of the living body at the time of measuring the pulse wave signal;
A blood component measuring apparatus comprising: a processing unit that processes calculation of a blood concentration of a predetermined blood component from the measured pulse wave signal based on the acquired pulse rate.   The blood component measuring apparatus according to claim 1, wherein the pulse rate acquisition unit calculates the pulse rate of the living body from the measured pulse wave signal.   The processing unit does not output the blood concentration of the predetermined blood component when the acquired pulse rate is not within an allowable range determined by a reference pulse rate related to the living body. The blood component measuring apparatus according to claim 1 or 2. The reference pulse rate for the living body is an average value of the pulse rate of the living body,
The blood component measuring apparatus according to claim 3, wherein the allowable range is a range of 95% to 110% of an average value of the pulse rate of the living body.   The blood component measuring apparatus according to claim 1, wherein the processing unit corrects the blood concentration of the predetermined blood component based on the acquired pulse rate. The blood component measurement device further includes
An absorption spectrum calculation unit for calculating an absorption spectrum of blood of the living body from the pulse wave signal;
A blood concentration calculation unit for calculating the blood concentration of the predetermined blood component from the absorbance indicated by the calculated absorption spectrum;
A pulse rate ratio calculating unit that calculates a ratio of the acquired pulse rate to a reference pulse rate related to the living body,
The blood component measuring apparatus according to claim 5, wherein the processing unit corrects the absorbance by dividing the absorbance indicated by the calculated absorption spectrum by the calculated ratio. The blood component measurement device further includes
A pulse rate ratio calculator that calculates a ratio of the acquired pulse rate to a reference pulse rate related to the living body;
Using a calibration curve indicating a correlation between the pulse rate ratio and the blood concentration calculation error of the predetermined blood component, and a conversion unit that converts the calculated ratio into an error,
6. The blood component measuring apparatus according to claim 5, wherein the processing unit subtracts the converted error from a blood concentration of the predetermined blood component calculated from the pulse wave signal. The blood component measurement device further includes
An absorption spectrum calculation unit for calculating an absorption spectrum of blood of the living body from the pulse wave signal;
A pulse rate ratio calculating unit that calculates a ratio of the acquired pulse rate to a reference pulse rate related to the living body,
The processing unit calculates the blood concentration of the predetermined blood component by fitting the absorbance indicated by the calculated absorption spectrum and the calculated ratio to a predetermined regression equation. Item 6. The blood component measuring apparatus according to Item 5. A pulse wave signal is measured based on the light received from the living body by irradiating light to the living body,
Obtaining the pulse rate of the living body at the time of measuring the pulse wave signal;
A blood component measurement method, comprising: calculating a blood concentration of a predetermined blood component from the measured pulse wave signal based on the acquired pulse rate.   Processing the calculation of the blood concentration of the predetermined blood component is performed when the acquired pulse rate is not within an allowable range determined by a reference pulse rate related to the living body. The blood component measuring method according to claim 9, comprising not outputting the concentration.   The processing of calculating the blood concentration of the predetermined blood component includes correcting the blood concentration of the predetermined blood component based on the acquired pulse rate. The blood component measuring method according to 1. On the computer,
Irradiating the living body with light and measuring the pulse wave signal based on the light received from the living body,
Obtaining the pulse rate of the living body at the time of measuring the pulse wave signal;
A blood component measurement program for processing calculation of a blood concentration of a predetermined blood component from the measured pulse wave signal based on the acquired pulse rate.   Processing the calculation of the blood concentration of the predetermined blood component is performed when the acquired pulse rate is not within an allowable range determined by a reference pulse rate related to the living body. The blood component measurement program according to claim 12, comprising not outputting the concentration.   The processing of calculating the blood concentration of the predetermined blood component includes correcting the blood concentration of the predetermined blood component based on the acquired pulse rate. The blood component measurement program according to 1.