JP4412644B2 - Cardiodynamic measurement device - Google Patents

Description

  The present invention relates to a circulatory dynamics measuring device that measures the properties of body fluid circulating in a living body, and is typically a technique related to a blood rheology measuring device that expresses fluidity generally referred to as smoothness / droolness of blood.

  Blood rheology measurement, which represents the fluidity of blood, which is called the smoothness of the blood, makes it possible to determine the microcirculatory blood flow that is the basis of human tissue activity, particularly by measuring the blood flow through the arteries. It is used for diagnosing diseases, evaluating the effects of drugs used, and so on. The circulatory dynamics measured in the present invention refers to a state in which blood and lymph fluid that moves inside the circulatory organ, gives oxygen and nutrients to living tissues and cells, and carries carbon dioxide and waste products constantly change over time. This includes, for example, flow velocity, flow rate change, fluidity, and pulse wave motion.

  As a means for measuring the viscosity of blood, a method based on blood collection (invasion) is a common method. However, due to the peculiarity of the act of blood collection, it is difficult to disseminate it in industrial fields such as clinical application equipment, food development equipment, and general health equipment that can be widely used in a general living environment that is not a medical institution. In order to solve this problem, the frequency change that occurs when the ultrasonic wave incident from outside the body is reflected by the blood flow, that is, using the Doppler effect and other data to complement the data such as temperature and volume pulse wave. A method for measuring blood rheology has already been proposed.

  The present applicant has also researched and developed this type of blood rheology measurement device and circulatory dynamics measurement device, and has already filed a patent application. Incidentally, Patent Document 1 provides a non-invasive blood rheology measurement apparatus that can easily measure blood rheology information without collecting blood from a subject when blood rheology measurement is performed, and further provides a small and configurable apparatus. The purpose of this study is to provide a means for easily measuring blood rheology at any time and anywhere, even if it is outside a medical institution without imposing a burden on the subject. Is based on a configuration comprising a means for noninvasively detecting a blood flow velocity flowing through a blood flow as a Doppler shift signal and a means for analyzing blood rheology from temporal changes in the blood flow velocity value detected by the means. A blood rheology that is small, portable, and can easily measure blood rheology anytime, anywhere, even outside of a medical institution without burdening the subject. Over the measuring device is presented.

  Patent Document 2 discloses a non-invasive method of inputting a wave from the surface of a living body, reflecting the blood flow through the living body, analyzing the blood state from the movement and position, and determining the circulatory dynamics to evaluate the health state. It is in. In addition, the objective is to make it possible to evaluate the health condition by obtaining an accurate blood flow velocity regardless of the measurement site of the living body. First, waves such as ultrasonic waves are transmitted from the skin surface of the living body. Then, the reflected ultrasound is received, the flow velocity of the blood flowing through the blood vessel is detected in the form of a Doppler shift signal, and then the temporal change component of the blood flow velocity value is obtained from the detected Doppler shift signal, The blood rheology that is one of the circulatory dynamics is measured from the change component and the health condition is evaluated. As an example of evaluating the health condition from the blood flow velocity component, blood rheology is obtained from the maximum velocity component of the blood flow velocity component during one pulse, and as a result the blood rheology is small, the evaluation that it is healthy A circulatory dynamics measuring device is presented.

The measurement by these apparatuses has a great feature that it can be performed without requiring blood collection. However, unlike the flow measurement in which the direction of the flow rate is known like the fluid flowing in the pipe, the absolute flow velocity is directly measured by the Doppler effect in the case of a blood flow flowing in a blood vessel with an unknown direction unknown in the body. It is not possible. That is, in these conventional apparatuses, a change in blood flow velocity can be obtained by measuring the Doppler effect, but an absolute blood flow velocity cannot be obtained. In addition, since biological information such as blood flow velocity, volume pulse wave, and temperature at the same measurement site is not measured, the measurement accuracy of physical quantities correlated with blood rheology is insufficient.
Japanese Patent Laid-Open No. 2003-159250 “Blood Rheology Measuring Device” published on June 3, 2003 Paragraph Nos. [0008] [0009] [Patent Document 1] Japanese Patent Laid-Open No. 2003-204964 “Circulation Dynamic Measurement Device” published on July 22, 2003 Paragraph Nos. [0007] [0011] Japanese Patent Laid-Open No. 6-169902 “Pulse-type Non-Intrusive Oximeter and Measurement Technique” Released on June 21, 1994

  The problem to be solved by the present invention is to solve the above-mentioned problems, that is, the blood flow velocity in absolute value can be directly obtained, and the blood rheology and the correlated physical quantity can be obtained with high measurement accuracy. The purpose is to present a method for measuring circulatory dynamics and to provide an apparatus for realizing it.

  The fluid velocity measuring method according to the present invention includes the detection Doppler signals Δf and Δf ′ of two sets of ultrasonic transducers arranged in different directions with respect to the flow velocity direction, and the arrangement angle between the two sets of ultrasonic transducers. The absolute value of the fluid velocity v is calculated from the information α according to the following equation.

v = c * [Delta] f / 2fcos [theta] = c * [Delta] f '/ 2fcos ([theta]-[alpha])
Here, c is the speed of sound in the propagation medium, and θ is an angle formed by the direction of transmission / reception of one ultrasonic sensor and the direction of piping.

  The blood flow velocity measuring device according to the present invention includes two sets of ultrasonic transducers arranged in different directions with respect to the blood flow direction, and detected Doppler signals Δf and Δf ′ of the two sets of ultrasonic transducers and 2 Computation means for performing computation according to the following equation from angle information α between the pair of ultrasonic transducers is provided, and an absolute blood flow velocity v is obtained.

v = c * [Delta] f / 2fcos [theta] = c * [Delta] f '/ 2fcos ([theta]-[alpha])
Where c is the speed of sound in the body, and θ is the angle formed by the direction of blood flow of one ultrasonic sensor and the direction of blood flow.

  In addition to the blood flow velocity measuring means described above, the blood flow velocity measuring device of the present invention is provided with any one or a combination of an optical sensor, a temperature sensor, and a pressure sensor in the vicinity of two ultrasonic transducers, A means for measuring the volume pulse wave, body temperature, and contact pressure of the part to be measured, which are physical quantities correlated with blood rheology, is also provided.

  Further, in the blood flow velocity measuring device of the present invention, the pressure sensor fits the ultrasonic block into the concave portion in the housing of the device, and the pressure sensor is disposed between the bottom surface of the concave portion of the housing and the back surface of the ultrasonic block, Further, the back surface of the ultrasonic block is presented in contact with the pressure block through a flexible substrate fixed to the apparatus housing.

  The blood flow velocity measuring device of the present invention presents a device including means for extracting only blood flow velocity data when the measured body temperature and / or contact pressure is within a set range.

  In addition, the blood flow velocity measuring device of the present invention multiplies the n heart rate maximum values of the blood flow velocity in the measurement span by the corresponding heartbeat peak value in the volume pulsation waveform obtained by the optical sensor, and during the measurement span. We present what has means to find the maximum normalized blood flow velocity by dividing by the maximum value of its peak value.

  Furthermore, the blood flow velocity measuring device according to the present invention is a means for dividing the average value of the normalized maximum blood flow velocity in the measurement span by the separately obtained maximum blood pressure value to obtain a corrected blood flow velocity indicating the degree of blood rheology. Present with

  And the blood-flow velocity measuring apparatus of this invention presents the thing provided with the heating means which warms the vicinity of a measurement site | part.

  The fluid velocity measuring method and apparatus according to the present invention include a detection Doppler signal Δf, Δf ′ of two sets of ultrasonic transducers arranged in different directions with respect to a flow velocity direction, and the two sets of ultrasonic transducers. Therefore, the absolute velocity of the fluid in a pipe arranged in a direction that cannot be accurately understood from the outside such as a blood vessel is calculated. Can be measured.

  Since the circulatory dynamics measuring apparatus of the present invention is provided with a pressure sensor, it can detect the state of contact pressure, thereby preventing the deformation of blood vessels and checking the state of poor contact. In addition, the back of the ultrasonic block employs a configuration in which a flexible substrate fixed to the device casing is interposed to contact the pressure block, so that the ultrasonic block does not get caught in the casing and operates stably. Realized.

  In addition, the circulatory dynamics measuring device of the present invention includes means for extracting only blood flow velocity data when the measured body temperature and contact pressure are within the set range, so that only normal measurement data can be extracted. High reliability.

  In the circulatory dynamics measuring device of the present invention, the temperature sensor and the pressure sensor are arranged together with the blood flow measurement sensor, so that related information at the same time at the same part can be detected as a set, so that stable reliability is eliminated except for measurement variations. High blood rheology measurement.

  Further, the circulatory dynamics measuring device of the present invention comprises means for obtaining a normalized maximum blood flow velocity using the peak value of the corresponding heartbeat in the volume pulsation waveform obtained by the optical sensor and the maximum value of the peak value. Thus, it is possible to eliminate noise caused by the fluctuation phenomenon of the living body that is not directly related to blood rheology.

  Furthermore, the hemodynamic measuring device of the present invention is a corrected blood flow velocity obtained by dividing the average value of the normalized maximum blood flow velocity in the measurement span by the separately obtained maximum blood pressure value as a physical quantity indicating the degree of blood rheology. Therefore, the degree of blood rheology can be measured by non-invasive means. Moreover, as a result of confirming the effect, the reliability was proved to be higher than that of the conventional type.

  And the circulatory dynamics measuring apparatus of this invention can be made to perform a normal measurement immediately, without measuring the unnatural blood flow of the cold body by employ | adopting the heating means which warms the vicinity of a measurement site | part. . Furthermore, by adopting closed loop control with a temperature sensor, it is possible to always perform measurement in an appropriate body temperature state stably.

  The principle of blood flow rate measurement, which is the basis of the present invention, will be described with reference to FIG. As shown in FIG. 1A, two sets of ultrasonic sensors 1a and 1b made up of piezoelectric elements for transmission and reception (ultrasonic transmitter and ultrasonic receiver) are arranged so as to be opposed to each other. The two sets of ultrasonic sensors 1a and 1b may be the same. The ultrasonic wave transmitted from the ultrasonic transmitter is reflected by the object and received by the ultrasonic receiver. If the object is stopped, the received wave is received as an ultrasonic wave having the same frequency as the transmitted wave. However, if the object is moving, the movement is superimposed and the frequency is changed and received. In the present invention, since the two ultrasonic sensors 1a and 1b are arranged so as to be opposed to each other, the blood vessels are arranged in the arrangement direction of the two ultrasonic sensors 1a and 1b as shown in FIG. When contact is made so that the directions are directed, one ultrasonic wave is incident with a flow direction component, and the other ultrasonic wave is incident with a direction component opposite to the flow. The received signals are reflected from the object that escapes in the former case, so that they are received at a frequency lower than the transmission frequency. Received. Now, assuming that the Doppler shift amount of the frequency is Δf and Δf ′, the angle formed by one ultrasonic sensor and the blood vessel direction is θ, and the angle formed by one ultrasonic sensor and the other ultrasonic sensor is α. The blood flow velocity v is expressed by the following equation.

v = c × Δf / 2fcos θ = c × Δf ′ / 2fcos (θ−α) (1)
Here, c represents the sound velocity in the body, and θ represents the angle between the transmission / reception system of one ultrasonic sensor and the direction of blood flow. Here, θ is an unknown number, but the value of θ can be calculated together with the blood flow velocity v from the simultaneous equations of equation (1).

  The approximate direction of the blood vessel can be observed from outside the body, but the exact angle, particularly the angle with respect to the skin surface, cannot be grasped. In the present invention, two ultrasonic sensors are arranged at a predetermined angle α, and the blood flow velocity in the blood vessel direction can be determined based on the principle described above. The simplest form of this blood flow rate measuring means is shown in FIG. In this measurement, a pair of ultrasonic sensors is arranged on an inclined surface having a V-shaped cross section, and measurement is performed by bringing a skin surface such as a fingertip into contact so that a blood vessel comes in a direction crossing both ultrasonic sensors.

  The circulatory dynamics measuring apparatus of the present invention correlates with blood rheology such as an optical sensor that measures volume pulse wave, a thermometer, or a pressure sensor that detects a contact pressure of a measured part, in addition to the blood flow velocity measuring means as described above. A means of measuring physical quantities was added. FIG. 2 shows an embodiment adopting this form. The optical sensor 2 and / or the temperature sensor 3 are arranged between two sets of ultrasonic sensors. As the temperature sensor 3, a thermistor or the like that can be easily output as an electrical signal is suitable. Body temperature greatly affects the expansion and contraction of blood vessels and is an important factor related to the state of blood flow. The optical sensor 2 includes a light emitting unit and a light receiving unit, and the light irradiated toward the blood vessel reaches the bloodstream. The hemoglobin in the blood has a light absorption effect, and the amount of light received by the light receiving unit decreases when the number of hemoglobin is large. The number of hemoglobins at the light irradiation position varies corresponding to blood pulsation. A technique for measuring a volume pulse wave based on this principle is already known. (See Patent Document 3) The embodiment shown in FIG. 3A includes both the optical sensor 2 and the temperature sensor 3, and the light emitting unit and the light receiving unit of the optical sensor 2 are arranged side by side with the temperature sensor 3. Is. 3B includes both an optical sensor and a temperature sensor. The light emitting unit and the light receiving unit of the optical sensor 2 are separately installed in the front-rear direction next to the temperature sensor 3. Is. Although not shown, a simple type in which only one of the optical sensor 2 or the temperature sensor 3 is disposed between two ultrasonic sensors is also possible.

  Data measured by the circulatory dynamics measuring apparatus of the present invention is shown in FIG. The one shown in A is the blood flow velocity waveform calculated by calculating the formula (1) from the two Doppler detection values obtained from the ultrasonic sensor, and the one shown in B is the volume measured by the optical sensor. It is a waveform of a pulse wave. However, the waveform of the volume pulse wave of B is displayed so as to be low when the detected light amount is reversed and the amount of received light is large. When blood flow increases, the number of hemoglobin increases, light absorption increases, and the amount of light received decreases, but in order to facilitate the correspondence with the blood flow rate shown in FIG. Such processing is performed. FIG. 6A shows a display in which two waveforms are superimposed. It can be seen that the pulsation is beautifully synchronized and supported. Although a low frequency component can be seen from the waveform than the frequency of pulsation, this is due to the fluctuation of the living body and has little relation to the blood rheology to be measured by the present invention. Therefore, in the present invention, standardized data is used in order to eliminate the influence of the fluctuation of the living body. That is, the n maximum values of the blood flow velocity synchronized with the heartbeat in the measurement span of several tens of seconds are multiplied by the peak value of the corresponding heartbeat in the volume pulsation waveform obtained by the optical sensor and the peak in the measurement span is obtained. Normalize by dividing by the minimum value. Specifically, normalization is performed as shown in the following equation.

Normalized maximum blood flow velocity: Vi ′ = Vi × Qi / min (Q _{1 to} Q _n ) (2)
In FIG. 6B, the value plotted with a circle is the maximum value of the blood flow velocity from the Doppler signal, and the value plotted with the symbol ▲ is divided by the minimum value in the volume pulsation waveform obtained by the optical sensor and normalized. Is. It can be seen that the low frequency components due to the shaking of the living body are eliminated.

Next, in the present invention, the viscosity is calculated from the normalized maximum blood flow velocity data V _i ′ obtained as described above and the maximum blood pressure value Pm, and a corrected blood flow velocity Vm indicating the degree of blood rheology is calculated. When the intra-arterial pressure is P and the blood viscosity is ν, the maximum blood flow velocity Vz in the artery is proportional to the intra-arterial pressure P and inversely proportional to the blood viscosity ν. Moreover, since the maximum blood pressure value Pm is proportional to the intra-arterial pressure P, the corrected blood flow velocity Vm is obtained by the following equation.

血流というものは体温による影響が大きい。冬の寒いときには体は冷やされ、血管が固く収縮された状態となる。この状態では血管の流体抵抗は大きくなり、血圧も高めとなることはよく知られている現象である。そこで本実施例の循環動態測定装置では温度センサー３を配置し、体温の状態をモニターする機能を備えるようにしている。そして、異常体温の状態で測定したデータは不採用とするようにしている。図７のＡに示したグラフは血流速度の波形と共にそのときの体温の状態を合わせて示したものである。いま、適正体温をＴ_１〜Ｔ_２の範囲であるとしたとき、その範囲を超えたｔ_１〜ｔ_２の期間があることがこのグラフから見て取れる。したがって、この場合、この区間のデータは採用しないものとする。

Blood flow is greatly affected by body temperature. When it is cold in winter, the body is cooled and the blood vessels are tightly contracted. In this state, it is a well-known phenomenon that the fluid resistance of the blood vessel increases and the blood pressure increases. Therefore, in the circulatory dynamics measuring apparatus of the present embodiment, the temperature sensor 3 is arranged to have a function of monitoring the body temperature state. The data measured in the abnormal body temperature state is not adopted. The graph shown in FIG. 7A shows the blood flow velocity waveform and the body temperature at that time. Now, assuming that the appropriate body temperature is in the range of T _{1 to} T ₂ , it can be seen from this graph that there is a period of t ₁ to t ₂ that exceeds the range. Therefore, in this case, data in this section is not adopted.

  In addition, the blood flow state is affected by the contact pressure of the sensor unit. When pressed tightly, the blood vessels are crushed and deformed, affecting the blood flow in that part. Therefore, in the embodiment shown here, a pressure sensor is provided so as to have a function of monitoring the contact state. In FIG. 4A, the ultrasonic block 1 is fitted into a concave portion in the casing 10 of the present circulatory dynamics measuring apparatus, and the pressure sensor 4 is interposed between the bottom surface of the concave portion of the casing 10 and the back surface of the ultrasonic block 1. Arranged. The contact pressure between the skin surface and the surface of the ultrasonic block 1 can be measured by the pressure sensor 4 via the ultrasonic block 1. The embodiment shown in FIG. 4B is a modification thereof. The basic structure in which the ultrasonic block 1 is fitted in the concave portion in the casing 10 of the circulatory dynamics measuring apparatus and the pressure sensor 4 is disposed between the bottom surface of the concave portion of the casing 10 and the back surface of the ultrasonic block 1 is the same. However, the back surface of the ultrasonic block 1 is not in direct contact with the pressure block 4 but with a flexible substrate 5 interposed. The flexible substrate 5 is fixed to the housing 10 by a connector 6. The flexible substrate 5 acts as a kind of leaf spring. When the contact pressure on the skin surface is transmitted through the ultrasonic block 1, the flexible substrate 5 is deformed by the flexibility and transmits the strain to the pressure sensor 4. When released from contact, the spring force acts to return the ultrasonic block 1 to the initial position. 4A does not have the flexible substrate 5, and when released from the contact, it may not be returned to the initial state because it may be caught in a slant in the concave portion of the housing 10 and the like. In the embodiment of B, the flexible substrate 5 is provided in order to make the return to the initial state more reliable.

FIG. 7B shows a graph display of the detected value of the pressure sensor together with the blood flow velocity waveform calculated from the Doppler signal of the ultrasonic sensor. Now, assuming that the contact pressure is normal when it is in the range of P _{1 to} P ₂ , in the example shown in this graph, the contact is made at an abnormal pressure in the range of the period t _{3 to} t ₄ . Therefore, data in this section is not adopted. Data employed becomes _t 0 ~t ₃ sections and _t 4 ~t _n intervals. When this circulatory dynamics measuring apparatus is provided with both the temperature sensor 3 and the pressure sensor 4, data as shown in FIG. 8A is obtained. As described above, the data in the section from t ₁ to t ₂ is not adopted from the body temperature information, and the data in the section from t ₃ to t ₄ is not adopted from the pressure information. Therefore, data used for data analysis are only those of _t 0 ~t ₁ and _t 2 ~t ₃ and ₄ ~t _n sections as shown in B of FIG.

  Based on the data thus adopted, a corrected blood flow velocity Vm indicating the degree of blood rheology is obtained by the above-described equation (3). The data actually obtained by the method of the present invention was collected from the blood of the same subject, and the blood rheology measured by the conventional measurement method was compared with the value. In the conventional measurement method, a predetermined amount of blood is measured by the time required to pass through the microchannel array with a predetermined water column pressure difference. The results are shown in Table 1.

本発明の手法による補正血流速度Ｖｍを縦軸に、従来測定法による全血流通過時間を横軸にしたグラフ上にデータをプロットしたものを図９に示す。このプロットした点は破線で示したような双曲線様の線上にあることが見て取れる。補正血流速度Ｖｍの値自体から血液レオロジーを判定することができるが、この補正血流速度Ｖｍと全血流通過時間との特性曲線を本発明の循環動態測定装置内に記憶させておけば、測定されたデータをデータ処理した値と別途測定された最高血圧値を入力して演算することにより、従来手法で得られる血液レオロジーの全血流通過時間（sec/100μl）の形で血液レオロジーを示すことができる。

FIG. 9 shows a plot of data on a graph with the corrected blood flow velocity Vm according to the method of the present invention on the vertical axis and the total blood flow passage time by the conventional measurement method on the horizontal axis. It can be seen that the plotted points are on a hyperbola-like line as shown by the broken line. Although the blood rheology can be determined from the value of the corrected blood flow velocity Vm itself, if the characteristic curve of the corrected blood flow velocity Vm and the total blood flow passage time is stored in the circulatory dynamics measuring device of the present invention. Blood rheology in the form of total blood flow passage time (sec / 100μl) of blood rheology obtained by the conventional method by inputting the value obtained by processing the measured data and the maximum blood pressure value measured separately. Can be shown.

  The following embodiment includes means for warming a cold body. As described above, when the body is cold, the blood vessel contracts and becomes hard, so normal blood flow measurement cannot be performed. Therefore, when the body temperature data detected by the temperature sensor is lower than the normal range, the body is warmed by a heating means such as a heater so as to be in the normal range. The measurement site in this embodiment is the fingertip, and the site where the heating means warms the body is the part from the palm to the arm. Place the elbow to the fingertip on the base of the device, and place the sensor part on the fingertip. The heating part from the palm to the arm should be a tunnel shape to warm not only the pedestal but the entire arm circumference, but taking into account the difference in arm thickness, the form of covering the semi-cylindrical member as rotatable Good. As a modification, an electric blanket type may be wound around the arm. Further, it is preferable to provide a heat insulating structure between the sensor unit so that the heat of the heating means does not cause noise to the temperature sensor.

  A system block diagram of this embodiment is shown in FIG. A common driving circuit for driving the transmitting piezoelectric elements of the two sets of ultrasonic sensors 1 and 2, each receiving circuit for processing a signal received by each receiving piezoelectric element, and driving for driving the light emitting element of the optical sensor 2 A measuring section is constituted by a receiving circuit for processing the signal and the signal received by the light receiving element, a detecting circuit for heat detecting means as the temperature sensor 3, a pressure sensor 4 for detecting contact pressure, and the detecting means. Further, in this embodiment, a heating means for warming the body temperature is provided, and a temperature adjustment circuit for adjusting the heating intensity of the heating means in accordance with the outputs of the temperature sensor and the detection circuit functions. When the body is warmed by the heating means and the body temperature of the fingertip rises, the temperature sensor 3 detects this and a closed loop control system is configured. In addition, an information input unit is provided, and a function of inputting related information such as blood pressure values, the date and time when the measurement is performed, the name of the person to be measured, and the like to the system. Also, a calculation unit that calculates the measurement value and the input value and calculates desired data, a storage unit that stores them, and a display unit that displays the measurement value and the data obtained by calculation in an appropriate form are provided. .

  The measurement operation of this system will be described with reference to the flowchart shown in FIG. A measurement part such as a fingertip is placed on the sensor unit, a semi-cylindrical heating cover is placed on the arm, and the power is turned on to start measurement. In step 1, the fingertip is brought into contact with the sensor unit with an appropriate pressure. In step 2, the temperature sensor 3 is measured, and in step 3, it is determined whether the set range is indicated. If it is within the set range, the process proceeds to step 8 as it is, but if it is outside the set range, it is displayed in step 4 that it is outside the set temperature range, and in step 5, the temperature adjustment circuit functions to heat the heating means. . In step 6, it is determined again whether the set temperature range is indicated. If it is still outside the range, the process returns to step 5 and heating by the heating means is continued. When the temperature is within the set temperature, the display indicating that the temperature is outside the set temperature range is erased in step 7, and the process proceeds to step 8 to perform contact pressure measurement. In step 9, it is determined whether the measured value indicates a set range. If it is within the set range, the process proceeds to step 14 as it is, but if it is outside the set range, it is displayed at step 10 that it is outside the set pressure range, and at step 11, the contact pressure of the fingertip is adjusted in the range direction. In step 12, it is determined again whether the set pressure range is indicated. If it is still outside the range, the process returns to step 11 to adjust the contact state. If the pressure is within the set pressure, the display indicating that the pressure is out of the set pressure range is erased in step 7, and the process proceeds to step 14 to start ultrasonic measurement. In step 15, it is determined whether or not the Doppler sound has been collected. If the Doppler sound has been collected, the process immediately proceeds to step 18, but if it has not been collected, the ultrasonic input / output is adjusted in step 16. When the Doppler sound can be sampled by adjusting the ultrasonic input / output at Step 17, the process proceeds to Step 18, but when the Doppler sound cannot be sampled at Step 17, the process returns to Step 1 and starts again. When the Doppler sound can be collected, it is checked whether the Doppler signal is at an appropriate level and the level is adjusted. In step 19, this level-adjusted Doppler signal is stored and stored in the storage unit in a time series together with the measured body temperature and the measured contact pressure over one measurement span of about several tens of seconds. Subsequently, blood pressure is separately measured in step 20, and the blood pressure value is input to the system and stored in the storage unit in step 21. The measurement operation of this system is completed by this series of operations.

Next, the data processing operation of this system will be described with reference to the flowchart shown in FIG. First, in step 1, the measurement data stored in the storage unit of the present system is read out to the work area. In step 2, it is determined whether or not the set temperature range and set pressure range have not been exceeded during measurement. This determination is checked based on body temperature measurement information and contact pressure information stored together with time information. If the measurement is continued in the stable state within the set range during the measurement period, the data is taken as it is, and the process proceeds to Step 5. If there is a state outside the set range during the measurement period, the measurement period is set at Step 3. Specify the period that was within the medium setting range. Then, in step 4, only the measurement data for the period within the set range is extracted, and the process proceeds to step 5. Using the two sets of ultrasonic Doppler signals and the two sets of ultrasonic sensor installation angles α, an angle θ between one ultrasonic sensor radiation direction and the blood flow direction is calculated based on the equation (1). Subsequently, in step 7, the absolute value v of the blood flow flowing in the blood vessel whose orientation is known is calculated. In step 8, a time period, that is, a pulse is detected from the volume pulse wave measured by the optical sensor. In step 9, the maximum blood flow velocity signal Vi for each heartbeat is obtained from the blood flow absolute velocity waveform, and the maximum value Qi for each heartbeat and the minimum value min (Q _{1 to} Q _n ) within the measurement span are obtained from the volume pulse waveform information. Extract. In step 10, the maximum blood flow velocity normalized according to equation (2) is obtained using the data extracted in the previous step. In step 11, an average value of the normalized maximum blood flow velocity is obtained, and in step 12, the calculation based on the expression (3) for dividing the normalized average blood flow velocity value by the maximum blood pressure value Pm is executed. Thus, the corrected blood flow velocity indicating the blood rheology value finally obtained by the system is calculated. This completes the data processing operation.

  In the above description, the technique of the present invention has been aimed at measuring blood rheology. However, two sets of ultrasonic transducers arranged in different directions with respect to the flow velocity direction, and the two sets of super The blood flow velocity measuring method according to the present invention for calculating the blood flow velocity v of the absolute value from the detected Doppler signals Δf, Δf ′ of the ultrasonic transducer and the angle information α between the two ultrasonic transducers, The present invention is not limited to measurement and can be widely applied to general fluid velocity measurement in pipes. In general pipe flow velocity measurement, the position, direction, and shape of the pipe are known, but this measurement method is applied as it is to flow velocity measurement in pipes where the position, direction, and shape of the pipe are unknown. The absolute flow velocity can be measured.

It is a figure explaining the principle which measures the absolute flow velocity used as the foundation of this invention. It is a figure which shows one Example of this invention, and shows the arrangement | positioning form of a sensor part with a cross section. It is the figure which showed the specific example of arrangement | positioning of what was equipped with the optical sensor 2 and the temperature sensor 3 together. It is a figure which shows the Example provided with the pressure sensor. It is a figure which shows the blood-flow velocity waveform from an ultrasonic sensor, and the signal waveform obtained from an optical sensor. A is a graph showing a correlation between a blood flow velocity waveform measured simultaneously and a signal waveform obtained from an optical sensor, and B is a diagram showing basic data and normalized data of a maximum blood flow velocity. It is a figure explaining the measurement check by a temperature sensor and a pressure sensor. It is a figure explaining the time slot | zone used for data analysis as a normal value. It is a graph of the effect confirmation which compared the correction | amendment blood flow velocity by this invention, and the value by a conventional method. It is a system block diagram which shows the basic composition of this invention. It is a flowchart which shows the measurement operation by the system of this invention. It is a flowchart which shows the signal processing operation by the system of this invention.

Explanation of symbols

1 Ultrasonic block 5 Flexible substrate
1a, 1b Ultrasonic sensor 6 Connector 2 Optical sensor 10 Device housing 3 Temperature sensor 4 Pressure sensor

Claims (7)

Two sets of ultrasonic transducers arranged in different directions with respect to the blood flow direction, and the angle between the detected Doppler signals Δf and Δf ′ of the two sets of ultrasonic transducers and the two ultrasonic transducers and an arithmetic means for performing arithmetic according to the following equation from the information alpha, a measuring method for determining the blood flow velocity v of absolute value,
An optical sensor is arranged in the vicinity of the two sets of ultrasonic transducers,
N maximum values of blood flow velocity synchronized with the heartbeat within the measurement span, a corresponding heartbeat peak value in the volume pulsation waveform obtained by the optical sensor, and a minimum value of the peak value within the measurement span; A circulatory dynamics measuring device comprising means for obtaining a normalized maximum blood flow velocity using the
v = c * [Delta] f / 2fcos [theta] = c * [Delta] f '/ 2fcos ([theta]-[alpha])
Where c is the speed of sound in the body, and θ is the angle formed by the direction of blood flow of one ultrasonic sensor and the direction of blood flow. The two pairs of temperature sensors in the vicinity of the ultrasonic transducer, disposed one or a combination of pressure sensors, body temperature is a physical quantity that correlates with blood rheology, features a means for measuring the contact pressure of the measuring section The circulatory dynamics measuring device according to claim 1 . The circulation according to claim 2 , wherein the pressure sensor has an ultrasonic block fitted in a concave portion in a housing of the apparatus, and a pressure sensor is disposed between the bottom surface of the concave portion of the housing and the back surface of the ultrasonic block. Dynamic measurement device. The circulatory dynamics measuring device according to claim 3 , wherein a back surface of the ultrasonic block is in contact with the pressure block through a flexible substrate fixed to the device casing. Circulatory dynamics measurement apparatus according to any one of claims 2 to 4, further comprising a means for extracting only the blood flow rate data when in the measurement above body temperature and / or the contact pressure is set range. The average value of the normalized maximum blood flow speed in said measurement span is divided by separately systolic blood pressure value determined, wherein the Ru comprising means for obtaining the correction blood flow velocity indicating the degree of the blood rheology The circulatory dynamics measuring device according to any one of claims 1 to 5 . Circulatory dynamics measurement apparatus according to any one of claims 2 to 6, wherein Rukoto comprising a heating means for heating the vicinity of the measurement site.

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