JP2019146944A - Non-invasive blood sugar level measuring device for estimating blood sugar level from change in temperature of human body - Google Patents

Abstract

A non-invasive blood glucose level measuring device for measuring a blood glucose level from a temperature change of a human body without requiring blood collection. A small-sized blood sugar level measuring device is realized so that a healthy person can easily use it in life. We propose a unique non-invasive blood glucose measurement device that uses the phenomenon of heat dissipation on the body surface when the human body consumes blood glucose. Conventionally, parameters such as blood oxygen concentration and blood oxygen supply were required.In this proposed technology, a table of adjustment parameters is prepared in advance so that these differences can be absorbed in advance, and the sensor side By providing a storage unit for various parameters, we succeeded in miniaturization and simplification. [Selection diagram] FIG.

Description

  The present invention relates to a non-invasive blood sugar level measuring apparatus that measures blood sugar levels of a human body without requiring blood collection.

  The blood glucose level measurement method using the conventional finger pricking method is not only painful but also burdens diabetic patients because the needle and tip cannot be reused. 2. Description of the Related Art As a blood glucose measurement device that non-invasively measures blood glucose in a human body, a spectroscopic analysis device that applies visible light or infrared light to the human body and analyzes the spectrum of transmitted or reflected light is known. For example, in Japanese Patent Application Laid-Open No. 3-173535 and Japanese Patent Application Laid-Open No. 5-176717, a human body is irradiated with near infrared light, and the blood glucose level of the human body is estimated by measuring the intensity of the transmitted light. In Japanese Patent Laid-Open No. 2-286132 and Japanese Patent Laid-Open No. 4-144545, as a method of measuring blood glucose level of a human body in a minimally invasive manner, blood fluid is oozed from the human body and the blood glucose level in the body fluid is measured. Is used. These are some examples, and various other devices for measuring blood glucose levels in a noninvasive or minimally invasive manner have been invented, but no examples have actually been put into practical use.

Japanese Patent Laid-Open No. 3-173535 Japanese Patent Application Laid-Open No. 5-176717 JP-A-2-286132 JP-A-4-144545 Japanese Patent No. 3884036

Diabete & Metabolisme, “Facial and substituting temporary changes following intravenous glucose injection in diabetics” by R.D. M.M. Hilson and T. D. R Hockday, 1982. 8.15-19 Temperature Influencing on Non-invasive Blood Glucose Measurement. Zhang, X. et al. , & Yeo, J .; H. , Doi: 10.1117 / 12.804281, 2009

Glucose in blood (this value is referred to as blood glucose level) is used in the cell for the glucose oxidation reaction, and produces energy necessary for maintaining the body. In particular, since most of the produced energy is thermal energy for maintaining body temperature, there is a relationship between blood glucose level and body temperature.
In fact, in the study “Facical and Substituting Temperature Changing Flowing Intravenous Glucose Injection in Diabetes” conducted by Hilson et al., Glucose was injected into the human body and the temperature of the skin (cheek) was confirmed within 2 minutes. However, these studies (Hilson et al. & Zhang et al.) Have only proved that the accuracy of blood glucose estimation by near-infrared spectroscopy is improved by taking into account changes in skin temperature. is there. As it is, the non-invasive blood sugar level measuring device requires a laser beam and a temperature sensor, which makes it difficult to simplify the measuring device, and hurdles remain in daily use.

The blood glucose level measuring apparatus of the present invention measures a non-invasive blood glucose level, and captures the heat dissipation of the body, the storage unit for storing the rising blood glucose level, the blood glucose level during life, the sex and age of the user, and the like. It is a measuring device having a function of calculating a blood sugar level based on information input from the calorie measuring unit and the calorie measuring unit and correcting the blood sugar level calculated from the parameters stored in the storage unit.
Blood sugar is supplied to cells throughout the body by the vascular system, particularly by capillaries. The human body contains complicated and diverse metabolic transmission pathways. Glucose (blood glucose) oxidation means that blood glucose and oxygen react, and water and carbon dioxide produce energy. This oxygen is oxygen supplied from the blood to the cells. On the other hand, heat generated by the human body due to glucose oxidation can be expressed as heat dissipation of the human body. In general, heat dissipation can be expressed only by convective heat and radiant heat.

Actually, the following model is proposed in the proposal of Japanese Patent No. 3884036.
(1) The amount of heat dissipation can be expressed as a function of blood glucose level and oxygen supply in the blood.
(2) The oxygen supply amount is determined by the blood hemoglobin concentration, the blood hemoglobin oxygen saturation, and the blood flow in the capillaries.
(3) The amount of heat dissipation is determined mainly by convection heat and radiant heat.
According to this model, it has been proved that the body surface can be measured by heat, and at the same time, parameters relating to oxygen concentration in the blood can be measured, and the blood glucose level can be determined with high accuracy using these measurement results. As an example of this, a part of a human body and a fingertip are cited as the measurement for obtaining the parameter. Convection and radiant heat can be obtained by thermal measurement. The blood hemoglobin concentration and blood hemoglobin oxygen saturation can be determined by spectroscopically measuring hemoglobin in blood and determining the concentration ratio of hemoglobin bound to oxygen.

However, in the method of Japanese Patent No. 3884036, an optical measurement unit that always uses light having two or more wavelengths is necessary because of the configuration, and it is difficult to reduce the size of hardware. We considered whether blood glucose levels could be measured with simple objects such as temperature sensors. Therefore, the following experiment was performed and the results were analyzed.
□ Outline of experiment Have the subject enter the room. Measure indoor temperature 3. 3. Measurement of skin temperature and body temperature 4. Calculate heat dissipation (radiant heat, convection heat), etc. Measure blood glucose level with an existing invasive auto-blood glucose meter 4. For Stefan Boltzmann theory, radiant heat is proportional to the fourth power of the surface temperature, convective heat is a heat transfer coefficient (4-5 for human skin) Since it is known that this is the product of the difference between the surface temperature and the air temperature, it can be derived by the formulas (1) and (2).

This time, eight experiments were performed on one subject and the results were summarized. Table 1 shows a list of blood glucose levels obtained during the experiment. The room temperature was kept at 28 degrees using an air conditioner, and the skin temperature was measured with an infrared thermometer. Equation 3 was obtained by performing linear regression analysis using the obtained blood glucose level as an objective variable and convection heat / radiant heat as explanatory variables.

When EGA analysis was performed to examine the blood glucose level measurement accuracy with respect to Equation 3, the result of FIG. 4 was obtained. Table 2 shows a list of actual blood sugar levels and blood sugar levels estimated from the equation (3), and FIG. 2 shows the results of EGA analysis. The EGA analysis is an international method for examining the accuracy of the developed blood glucose level measuring apparatus. Zone A in FIG. 3 can be used for clinical use, and zone B is within tolerance. For this reason, if Equation 3 is used, blood oxygen saturation and oxygen supply amount are not required, and the blood glucose level is obtained with high accuracy.

  Further, the blood glucose level estimated from the equation (3) can be corrected by a user periodically performing a blood test and using the result. As an example, using the formula (3), the blood glucose level upon waking up is “95”, and the blood glucose level is “92” as a result of the blood test. It can be seen that there is an error of “+3” with respect to the measured value from the temperature and skin temperature at that time and the value of the result. In the subsequent measurement, higher accuracy can be realized by taking this into account.

  In addition, the heat dissipation of the human body varies by age and gender. Therefore, a model of heat dissipation is established for each age and gender, and linear regression analysis is performed to calculate mathematical formulas separately. The best results can always be obtained by storing these and switching the formula to be used according to the user.

  Further, both the blood test results and the correction means based on age and sex can be used at the same time.

Configuration diagram of a non-invasive blood sugar level measuring device using the theory of the present invention Results of EGA analysis PAD diagram of blood glucose level measurement Processing result display method

  Next, a specific apparatus configuration for realizing non-invasive blood sugar level measurement according to the principle of the present invention will be described.

  FIG. 1 shows a configuration diagram of a noninvasive blood sugar level measuring apparatus proposed in the present invention. The device has a calorific value measurement unit that measures temperature and heat dissipation from the fingertips (a sensor that measures temperature and a sensor that measures heat dissipation are different) and an information storage unit that stores the user's rising blood glucose level, sex, and age. Exists.

In the embodiment proposed in the present invention (see FIG. 1), the storage unit / blood glucose level estimation unit and calorific value measurement unit are each divided into two pieces of hardware. In this embodiment, the storage unit / blood glucose level estimation unit is implemented on a smartphone, and the calorific value measurement unit is implemented on a small microcomputer board.
Moreover, the information communication part which can transmit / receive the information measured by the calorie | heat amount measurement part and the communication from a smart phone by radio | wireless communication is provided in the small microcomputer board side.

  In the calorimeter, a sensor for measuring the temperature and a sensor for detecting the heat dissipation of the user are also separate. The user measures the blood glucose level by having his / her fingertip touch a sensor (see FIG. 1, S1) that acquires heat dissipation.

  FIG. 3 shows a processing flow on the small microcomputer board / smartphone side in the blood glucose level measurement of the present proposal.

The user first inputs age / sex, normal blood sugar level, etc. from the smartphone before measuring the blood sugar level. Then, wait for the temperature measurement (1-10 seconds). After the temperature measurement is completed, the fingertip is placed on the heat dissipation acquisition sensor, and the heat dissipation of the human body is acquired in about 30 seconds.
The obtained temperature and heat dissipation are substituted into the formulas 1 to 3 proposed in the present invention, and the blood glucose level is estimated. At that time, the estimated blood glucose level is corrected using the information input / stored in the information storage unit.

  Moreover, an information communication part communicates for every said process, and notifies to the smart phone side. The smartphone displays the result of processing to the user by performing screen / sound according to the content of the notification.

  Body surfaces other than fingertips can also be used to measure heat dissipation. For example, skin of earlobe, forearm, wrist, etc. can be cited as an example of a place with high temperature stability and suitable for measurement.

Hereinafter, the reference numerals in FIG. 2 will be described.
A: The estimated blood glucose level is ± 20% from the actual value (high accuracy)
B: The estimated blood glucose level has a difference of about 20% to 30% (within an allowable error range).
C: Estimated blood glucose level is judged to have a problematic accuracy D: Value that has failed or is impossible in practice (such as 70 or less)
E: Serious problems in blood glucose management

Hereinafter, the reference numerals in FIG. 3 will be described.
D1: Start of initial program D2: Circuit operation test program D3: Measure ambient air temperature with temperature sensor D4: Use communication unit to instruct to place smartphone on smartphone D5: Fingertip temperature D6: Transmitting the temperature sensor measurement value to the smartphone via the communication unit

Hereinafter, reference numerals in FIG. 4 will be described.
S1: Start of initial program S2: Continue processing if communicating with small microcomputer board S3, 4: If received data is numeric, record. If not, send a screen notification to the user. S5, S6, S7: Calculate the heat dissipation / blood glucose level from the recorded values, and then notify the screen.

Claims (7)

  A calorimetry unit that measures the temperature derived from the body surface and obtains information used to calculate the convective and radiant heat related to heat dissipation from the body surface, and the blood glucose level at the time of user's wake-up collected separately by existing blood test kits and devices Based on the formula obtained from the linear regression analysis based on the MHC theory from the storage unit storing the blood glucose level and the daily blood glucose level, and the plurality of parameters input and stored in the calorific value measurement unit and the storage unit A blood sugar level measuring apparatus having a function having a blood sugar level estimating unit for estimating a blood sugar level.   2. The blood sugar level measuring apparatus according to claim 1, wherein the calorific value measuring unit measures an environmental temperature measuring unit that measures an environmental temperature and an ambient temperature, and a temperature emitted from the surface of the human body by contacting a part of the body. A blood glucose level measuring device comprising two independent temperature measuring sensors for measuring.   3. The blood sugar level measuring apparatus according to claim 2, wherein the two sensors of the calorific value measuring unit are respectively arranged at a physically constant distance and adjusted so as not to affect each other during measurement. apparatus.   A calorific value measurement unit and a blood glucose level corresponding to a function for estimating a blood glucose level by applying the caloric value measured by the blood glucose level measuring device according to claim 1 to a relational expression of a blood glucose level and a caloric value for each age prepared in advance A blood glucose level measuring device having a value estimation unit.   A calorific value measurement unit and a blood glucose level corresponding to a function of estimating a blood glucose level by applying the calorie measured by the blood glucose level measuring device according to claim 1 to a relational expression between a blood glucose level and a calorific value for each sex prepared in advance. A blood glucose level measuring device having a value estimation unit.   The calorific value measured by the blood sugar level measuring apparatus according to claim 5 is applied to a relational expression of blood sugar level and caloric value for each age and sex prepared in advance, and corresponds to a function for estimating a blood sugar level. Is a blood glucose level measuring device having a calorific value measuring unit, a blood glucose level estimating unit, and a storage unit corresponding to a function of correcting based on the value of the blood test result input and stored in the storage unit.   7. The blood glucose level measuring apparatus according to claim 6, wherein the estimated blood glucose level is different from a currently proposed method (metabolic fever / blood oxygen concentration / blood flow utilization type and laser infrared spectroscopy technique utilization type), oxygen supply A blood glucose level measuring apparatus characterized in that it is a blood glucose level estimated only by calorimetry without requiring parameters of volume and blood oxygen concentration.

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