JP2010148690A - Blood information extractor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a blood information extractor capable of noninvasively detecting blood condition from an apparent pulse wave velocity or others without sampling blood from a subject. <P>SOLUTION: The blood information extractor 1 includes a pulse wave meter 12 for measuring the pulse wave, an electrocardiograph 11 for measuring the action potential of a heart, a sphygmomanometer 14 for measuring blood pressure P, and arithmetic means 18. The arithmetic means 18 carries out the processing for calculating the apparent pulse wave velocity (C) and the processing for calculating a blood condition index (I) according to formulation: I=kP/2C<SP>2</SP>(k is a constant) using the calculated apparent pulse wave velocity (C) and the blood pressure (P) measured by the sphygmomanometer. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an apparatus capable of noninvasively extracting blood information from an apparent pulse wave velocity or the like without collecting blood from a subject.

  In recent years, interest in the fluidity state such as blood smoothness and muddy has increased from the health consciousness. In a bloody state, red blood cells, white blood cells, and the like change, and blood does not flow smoothly in the capillaries. In this case, the risk of blood clotting and clogging of blood vessels increases, which in turn can cause cerebral infarction, myocardial infarction, and economy syndrome.

  Causes of blood becoming muddy have been pointed out as long-term factors such as overeating, lack of vegetables, irregular diets, obesity, hypertension, diabetes, gout, constitution, smoking, drinking, stress, etc. . In the short term, the blood smoothness and muddyness change depending on the amount of water intake, physical condition, etc. even within a day. Therefore, it is required that blood information can be easily monitored.

For example, Patent Document 1 describes a method of measuring the pulse wave velocity and measuring the degree of arteriosclerosis. Patent Document 2 describes a method for calculating an estimated blood vessel age from a measured pulse wave.
However, these are all intended to measure the state of blood vessels and are not methods for measuring the state of blood.
JP 2004-321438 A JP 2000-511166 A

  Therefore, an object of the present invention is to provide an apparatus that can extract blood information non-invasively from an apparent pulse wave velocity without collecting blood from a subject.

In order to achieve the above object, the blood information extraction device of the present invention comprises:
A pulse wave meter that measures a pulse wave at a first part of a living body, an electrocardiograph that measures a heart action potential as a reference pulse at a second part of the living body, a blood pressure meter that measures blood pressure (P), and an arithmetic means And comprising
The computing means is
Based on the propagation time observed between the reference pulse measured by the electrocardiograph and the pulse wave measured by the pulse wave meter, and the distance between the first part and the second part Processing to calculate the apparent pulse wave velocity (C);
Using the apparent pulse wave velocity (C) calculated and the blood pressure (P) measured by the sphygmomanometer, the equation:
I = kP / 2C ² (k is a constant)
The blood state index (I) is calculated according to the following.

“Blood condition index I” roughly corresponds to the blood density, and when this value is high, it is judged as a blood dripping tendency, and when it is low, it is judged as a blood smooth tendency.
The pressure P may be, for example, the maximum blood pressure (Ps) or the minimum blood pressure (Pd), or the average value of the maximum blood pressure and the minimum blood pressure ((Ps + Pd) / 2). As the constant k, an average value βm of stiffness parameters β (details will be described later) may be used.

The apparatus of the present invention further includes
An echo device for measuring the carotid artery diameter (Ds) at the highest blood pressure (Ps) and the carotid artery diameter (Dd) at the lowest blood pressure (Pd);
In the process of calculating the blood state index (I), the equation: is obtained using Ds and Dd obtained by the echo device.
I = βP / 2C ²
β = Dd / (Ds−Dd) · ln (Ps / Pd)
(Β is the stiffness parameter)
The blood condition index (I) is calculated according to

The apparatus of the present invention further includes a display unit for displaying predetermined information to the subject, and the calculation unit includes:
A process of performing statistical processing using a plurality of data of the calculated blood condition index (I) and calculating an average value (I _m ) of the blood condition index;
A process of calculating a value of (I−I _m ) using the average value (I _m ) and the calculated blood condition index (I);
The display means displays the value of (I−I _m ) or a blood state corresponding to the value (for example, a symbol or the like).

  Further, in the process of calculating the apparent pulse wave velocity (C), the propagation time is obtained from the end of the ST period of the electrocardiogram and the pulse wave rising point, and the reach is the distance between the right hand tip and the left hand tip of the subject. The pulse wave velocity (C) may be calculated with a length (r) of ½ as a distance between the first part and the second part.

  According to the present invention, as described above, it is possible to provide a blood information extraction device that can extract blood information non-invasively from the apparent pulse wave propagation velocity without collecting blood from a subject.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of an apparatus according to this embodiment.

  As shown in FIG. 1, the blood information extraction apparatus 1 of the present embodiment includes an electrocardiograph 11 for obtaining information on the action potential of the heart, a pulse wave meter 12 for obtaining information on the pulse wave, and a carotid artery diameter. And an sphygmomanometer 14 for obtaining blood pressure information.

  In addition, the apparatus 1 includes a calculation unit 18 that performs a predetermined calculation (detailed below) based on the information obtained from these. For example, the calculation unit 18 has an input means (keyboard, mouse, etc.) (not shown) having, for example, a half length r of the reach from the right hand tip to the left hand tip when the patient spreads both arms. Input is possible. The device 1 also includes display means (not shown) such as a display.

  A conventionally known electrocardiograph can be used as the electrocardiograph 11, and information on the action potential of the heart as shown in FIG. Here, “ST” indicates a time during which the entire heart is excited (for example, 0.1 to 0.15 seconds), and “T” indicates a time for which the excitability of the ventricle is recovered (for example, 0.2 to 0.6 seconds). ).

  The pulse wave meter 12 is not particularly limited as long as it can measure a volume pulse wave. The pulse wave meter 12 may be a system using a pressure sensor or a strain sensor, but a system using an optical sensor is particularly preferable. For example, an optical sensor at the fingertip irradiates infrared rays and detects a blood flow volume based on a change in transmitted light due to the total amount of hemoglobin in the blood.

  The sphygmomanometer 14 measures the maximum blood pressure Ps and the minimum blood pressure Pd of the subject. The echo device 13 is for measuring the pulse diameter Ds at the maximum blood pressure Ps and the pulse diameter Dd at the minimum blood pressure Pd.

  The electrocardiograph 11, the pulse wave meter 12, the echo device 13, and the sphygmomanometer 14 may be prepared as individual devices, or each function may be included in one device. You may use what was provided. For example, a known device that can automatically monitor an electrocardiogram, a pulse wave, and a blood pressure at the same time (simultaneously) may be used. Moreover, the apparatus 1 which concerns on this invention may be comprised by incorporating the calculating part 18 in such an apparatus.

The calculation unit 18 calculates the blood state index I according to the following formula using the data obtained by each of the above devices (see: Motoaki Sugawara et al. “Blood Rheology and Blood Flow”, Japan MEE Society, 2003, Corona, p. 103-107).
In the following, an example in which the maximum blood pressure Ps and the minimum blood pressure Pd are used as blood pressure values will be described. Since the maximum blood pressure Ps and the minimum blood pressure Pd can be measured with a sphygmomanometer, they are clinically suitable.

β = Dd / (Ds−Dd) · ln (Ps / Pd) (1)
I = (βPs / 2C ² ) Equation (2)
Here, C is an apparent pulse wave velocity. Ds is the carotid artery diameter at the time of blood pressure Ps, and Dd is the carotid artery diameter at the time of blood pressure Pd. β is a stiffness parameter. In formula (2), Pd or an average value of blood pressure ((Ps + Pd) / 2) may be used instead of Ps.

  The stiffness parameter β can be obtained by substituting the values of Ps, Pd, Ds, and Dd obtained by the sphygmomanometer 14 and the echo device 13 into the equation (1). By substituting the values of β, Ps, and C into equation (2), the blood state index I can be obtained (see below for calculation of the apparent pulse wave velocity C).

The stiffness parameter β takes a different value for each blood vessel region, and the value increases with age. In addition, it is considered that β of each blood vessel increases with time and is proportional. In the actual calculation, it is difficult to obtain β of the blood vessel passing through the upper arm of the measurement site, so that β may be used in the equation on the assumption that it is proportional to β of the carotid artery. When the device 1 is used by the same person, the blood condition index I may be obtained with the value of the stiffness parameter β as k (constant). Alternatively, the calculation of Expression (2) may be performed using β _m which is an average value of the stiffness parameter β.

Calculation unit 18 also calculates an average value I _m by statistically processing the blood condition index I obtained as described above (see FIG. 3). Then, a deviation (I−I _m ) between the calculated blood state index I of the subject and the average value I _m is calculated, and the blood state is determined based on this. If the deviation (I-I _m) is negative, the blood is determined to silky tendency, if positive, it is determined that the mush tendency. The degree of the smooth tendency and the muddy tendency may be divided in stages according to the numerical value of the deviation (I−I _m ) (for example, −2, −1, 0, 1, 2,..., Etc.). ). Further, such a numerical value of (I−I _m ) may be shown on the display.

Regarding the calculation of the blood state index I, for example, if the action potential propagation time from the heart (second part) to the pulse wave measurement point (first part) is ΔT and the pulse wave propagation time is Δt,
Δt >> ΔT, V >> C (V: action potential propagation speed, C: apparent pulse wave propagation speed)
C = r / Δt (r: 1/2 of reach) [m / sec] (Expression 3)
It becomes.
The apparent pulse wave velocity C can be obtained from this equation. Note that Δt includes the time during which blood flows to the measurement point and the pulse wave propagation time. The apparent pulse wave propagation velocity C is a velocity obtained by adding the blood flow average velocity u and the pulse wave average velocity V together.

  Blood flow is affected by blood viscosity, and this blood viscosity depends on values such as ρ, Alb, and Ht. Therefore, conversely, information such as ρ, Alb, and Ht can be obtained from the measured value of Δt.

  Regarding the measurement of Δt, as shown in FIG. 2, the time during which the entire ventricle is excited is ST, so the time (Δt) connecting the rise of T and the rise of the pulse wave may be selected.

  As described above, according to the apparatus 1 of the present embodiment, the blood state is obtained by using the apparent pulse wave velocity C, blood pressure P, stiffness parameter β (if necessary), etc. without collecting blood from the subject. The index I can be obtained. When the same person uses the apparatus 1 of the present embodiment, the calculation is performed using the average value βm or an arbitrary constant k without calculating the parameter β, and the smoothness tendency and muddy tendency of the subject's blood are determined. It is also possible to determine (details below).

  By performing health care using the apparatus 1 according to the present invention, cerebral infarction and myocardial infarction can be prevented.

  Experiments were conducted to determine whether the relationship of I = k [Alb] and I = k [Ht] holds for Alb (albumin), Ht (hemacrit), etc., which have a large effect on blood viscosity, You may use for judgment of a tendency and a muddy tendency. Similarly, the relationship with plasma proteins, blood glucose, lipids, etc. may be considered.

The change with time of blood condition index I of each subject was observed for three subjects.
The pulse wave measurement point is preferably the carotid artery, but the index finger is used. Further, in the case of the same living body, it is considered that the parameter β does not change greatly within a short time (same measurement location), and therefore calculation was performed with β = 1. P was an average value of the maximum blood pressure and the minimum blood pressure. I is a CGS unit system.

  Measurements were taken after 30 minutes had elapsed after sufficient water was consumed by the subject. The results are shown in the table below.

  As shown in Tables 1 to 3, the blood condition index I per subject showed a tendency to increase over time for all three. In the case of the observation of the same living body for a relatively short time as described above, it was possible to know the change over time of the blood state of the subject without calculating (being constant) the parameter β.

1 is a block diagram of an apparatus according to an embodiment. It is a graph which shows an example of an electrocardiogram (A) and a pulse wave (B). It is a distribution showing the relationship between the average value I _m and the calculated blood condition index I in the statistical process.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Blood information extraction apparatus 11 Electrocardiograph 12 Pulse wave meter 13 Echo apparatus 14 Blood pressure meter 18 Calculation part

Claims (4)

A pulse wave meter that measures a pulse wave at a first part of a living body, an electrocardiograph that measures a heart action potential as a reference pulse at a second part of the living body, a blood pressure meter that measures blood pressure (P), and an arithmetic means And comprising
The computing means is
Based on the propagation time observed between the reference pulse measured by the electrocardiograph and the pulse wave measured by the pulse wave meter, and the distance between the first part and the second part Processing to calculate the apparent pulse wave velocity (C);
Using the apparent pulse wave velocity (C) calculated and the blood pressure (P) measured by the sphygmomanometer, the equation:
I = kP / 2C ² (k is a constant)
And a blood information extracting apparatus, which performs a process of calculating a blood state index (I) according to the method. further,
An echo device for measuring the carotid artery diameter (Ds) at the highest blood pressure (Ps) and the carotid artery diameter (Dd) at the lowest blood pressure (Pd);
In the process of calculating the blood state index (I), the equation: is obtained using Ds and Dd obtained by the echo device.
I = βP / 2C ²
β = Dd / (Ds−Dd) · ln (Ps / Pd)
(Β is the stiffness parameter)
The blood information extraction device according to claim 1, wherein the blood state index (I) is calculated according to Furthermore, a display means for showing predetermined information to the subject is provided,
The computing means is
A process of performing statistical processing using a plurality of data of the calculated blood condition index (I) and calculating an average value (I _m ) of the blood condition index;
A process of calculating a value of (I−I _m ) using the average value (I _m ) and the calculated blood condition index (I);
A process of causing the display means to display a display of the value of (I−I _m ) or a blood state corresponding to the value;
The blood information extraction device according to claim 1 or 2, wherein: In the process of calculating the apparent pulse wave velocity (C),
The propagation time is obtained from the end of the ST period of the electrocardiogram and the rising point of the pulse wave,
The apparent pulse wave velocity (C) is calculated by setting the length (r) ½ of the reach, which is the distance between the right hand tip and the left hand tip of the subject, as the distance between the first part and the second part. The blood information extraction device according to any one of claims 1 to 3.

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