JPH08154906A - Pulse wave measuring apparatus - Google Patents

Abstract

PURPOSE: To evaluate the condition of blood circulation as indicated by a blood pumping force of a heart and elasticity of a blood vessel easily and accurately. CONSTITUTION: First wave required time TS13 of a differentiation pulse wave to be obtained through a pulse wave sensor 1 and a differentiation processing part 2 is determined by a differentiating/first wave required time detecting section 5 as time interval between two points as detected by a rising point detecting section 3 and by an inclination 0 point detecting section 4 to provide an index for evaluating blood circulation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pulse wave measuring device used for health condition management, diagnosis, etc. in a health care room, a medical institution or a general household.

[0002]

2. Description of the Related Art Conventionally, as a pulse wave measuring device of this type,
The output of the pulse wave sensor that detects the increase or decrease in blood volume at the distal end of the body, such as the fingertip or earlobe, is differentiated twice, and the height of each peak (distance from the reference line) of the resulting waveform is compared. A configuration that determines the characteristics of a waveform is known (for example, Japanese Patent Laid-Open No. 57-93036).

FIG. 8 shows a specific example of the index calculation method of this pulse wave measuring apparatus. In FIG. 8, 11 is a curve showing an example of a waveform obtained by differentiating the output of the pulse wave sensor twice,
Indicates the position where the height of the waveform 11 is 0, that is, the reference line. Further, in FIG. 8, the height of the first peak 11a in the waveform 11 is a, the heights of the second, third, and fourth peaks 11b, 11c, and 11d are b and b, respectively.
It is described that the characteristics of the waveform are determined based on the magnitude relationship of the values of a to d, where c and d are used.

[0004]

However, in determining the characteristics of the waveform in the configuration of the conventional pulse wave measuring device described above,
Focusing only on the height of each peak of the second derivative waveform, it is an important factor that characterizes the shape of the waveform, and each peak is considered to have a deep relationship especially due to the blood pushing force of the heart and the elasticity of blood vessels. It was difficult to say that the characteristics of the waveform were sufficiently expressed without any consideration of the temporal positional relationship of.

The present invention solves the above problem and provides a pulse wave measuring apparatus capable of evaluating the state of blood circulation based on the values reflecting the temporal positional relationship of each part of the waveform. The purpose is to do.

[0006]

In order to achieve this object, the first means of the present invention is to differentiate the output of a pulse wave sensor for detecting an increase / decrease in blood volume in a differentiation processing section, and obtain a waveform obtained by this differentiation. The temporal position of the rising point is detected by the rising point detecting unit, and the temporal position of the point where the slope becomes 0 after the waveform passes through the maximum point is detected by the inclination 0 point detecting unit, and the inclination 0 from the rising point is detected. The time required to reach the point is configured to be detected by the differential first wave time required detector.

According to the second means of the present invention, the maximum point detecting section detects the temporal position of the point where the waveform obtained by the differential processing reaches the maximum, and the inclination becomes 0 after passing the maximum point. The temporal position of the point is detected by the inclination 0 point detecting unit, and the time required for the waveform to fall from the maximum point to the point where the inclination is 0 is detected by the differential wave fall required time detecting unit.

Further, the third means of the present invention is provided with an intersection point detecting section for differentiating the output of the pulse wave sensor twice and detecting the temporal position of the point where the waveform obtained by this crosses the reference line. The time required from the first crossing point to the third crossing point of the waveform obtained by the crossing point detection section is detected by the first to third crossing point necessary time detection sections.

Further, the fourth means of the present invention is provided with an intersection point detecting section for differentiating the output of the pulse wave sensor twice and detecting the temporal position of the point where the waveform obtained by this crosses the reference line. The required time from the second intersection to the third intersection of the waveform obtained by the intersection detecting section is detected by the second to third intersection required time detecting sections.

The fifth means of the present invention, in addition to the first to fourth means, is provided with a pulse rate detecting section for counting the pulse rate of the subject, and based on the pulse rate obtained by this means. Then, regarding the value of the differential first wave required time, the differential wave descent required time, the first to third intersection required times, or the second to third intersection required times obtained by the respective means, this is set to a predetermined reference pulse rate. The pulse rate correction calculation unit performs a correction calculation to a value corresponding to the measurement in 1.

[0011]

By the above-mentioned first means, it is possible to detect the time required for the first wave of the differential pulse wave which is considered to have a deep relationship with both the blood pushing force of the heart and the elasticity of the blood vessel. Based on this, the general blood circulation state of the subject can be easily and accurately evaluated.

By the second means, the time from the maximum point of the differential pulse wave waveform, which is said to have a strong relation mainly with the elasticity of the blood vessel, to the point where the slope becomes 0, that is, the differential wave descent required time. Can be detected, and the vascular elasticity of the subject can be evaluated.

Further, by the third and fourth means, only by detecting the intersection of the two-time differential waveform of the pulse wave and the reference line, the first differential wave which is to be obtained by the first or second means. The required time or the differential wave descent required time can be detected more simply and reliably as the first to third intersection required times or the second to third intersection required times.

Then, by the fifth means, the differential first wave required time or the differential wave descent required time, the first to third intersection required times, or the second to second obtained by each of the first to fourth means. The time required for the three intersections can be corrected to a value equivalent to the reference pulse rate, and even the measurement results under different conditions can be compared and evaluated uniformly.

[0015]

Embodiments of the pulse wave measuring apparatus of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of a pulse wave measuring apparatus according to an embodiment of the present invention, and FIGS. 2 and 3 are differential pulse waves and 2
Two typical waveform patterns of the differential pulse wave are shown. In each figure, the differential pulse wave is shown in the upper part and the corresponding differential pulse wave is shown in the lower part. Then, FIG. 4 is an operation explanatory diagram in the case where a pulse rate correction calculation is added to the differential pulse wave.

In FIGS. 1 to 4, 1 is a pulse wave sensor for detecting an increase / decrease in blood volume at a fingertip, 2 is a differential processing unit for differentially processing the output signal of the pulse wave sensor 1, and 3 is output from this differential processing unit. The rising point detector 4 for detecting the temporal position of the rising point S ₁ of the waveform A is the maximum point S _{2 of the} waveform A.
Reduce after passage, gradient 0 point detecting section for detecting a temporal position of the point S ₃ that the slope is 0, 5 rising point S _1
Is a differential first wave required time detecting unit for detecting a required time T _S13 from when the slope reaches the zero point S ₃ .

Reference numeral 6 denotes a pulse rate detecting section for counting the pulse rate n (FIG. 4) of the subject, and 7 denotes required differential first wave of the subject of pulse rate n obtained by the differential first wave required time detecting section 5. A pulse rate correction calculation unit that corrects the time T _n to a value T ₆₀ corresponding to the measurement at a predetermined reference pulse rate (60 beats / minute in FIG. 4), and 8 a control unit that controls the operation of each of these units.
Reference numeral 9 denotes a display unit that displays the measurement result.

Next, the operation of this pulse wave measuring device will be described. The pulse wave signal obtained by the pulse wave sensor 1 is differentiated by the differentiation processing unit 2, and a so-called differential pulse wave waveform A is obtained.
Detected as. Then, the temporal positions of the rising point S ₁ and the slope 0 point S ₃ of the waveform A are the rising point detection unit 3
And the first slope required time detection unit 5 detects the first slope required time, and the first differential wave required time detection unit 5 obtains the first differentiated wave required time T _S13 which is the time interval.

At this time, based on the pulse rate n simultaneously obtained by the pulse rate detection unit 6, the pulse rate correction calculation unit 7 follows the formula of T ₆₀ = T _n (n / 60) shown in FIG. The measurement result is corrected and calculated and displayed on the display unit 9 via the control unit 8.

If the correction calculation is not required, the pulse rate correction calculation unit 7 is not passed and the differential first wave required time detection unit 5 is used.
The configuration (not shown) may directly lead the output of the above to the control unit 8.

FIG. 5 is a block diagram showing another embodiment of the present invention corresponding to claim 2. In the figure, 10 is a maximum point detecting section for detecting the temporal position of the maximum point S ₂ of the waveform A, 11 Is the time T required for the waveform to fall from the maximum point S ₁ to the slope 0 point S _3.
It is a differential wave descent required time detection unit that detects _S23 .

The operation in this case is similar to that of FIG. 1, but the differential wave fall required time T _S23 is obtained instead of the differential first wave required time T _S13 in FIG.

FIGS. 6 and 7 are block configuration diagrams showing another embodiment of the present invention corresponding to claims 3 and 4,
First differential wave required time T obtained by the configurations of FIGS.
FIG. 6 shows a configuration for more simply and reliably _{obtaining S13} and the differential wave fall required time T _S23 . Reference numeral 12 in FIG. The point (X ₁ , X ₂ , X _{3 at which} the waveform A ′ of the so-called second derivative pulse wave obtained by the second differentiation intersects with the reference line X.
, Etc., the crossing point detection unit 14 detects the temporal position of the first crossing point X ₁ (corresponding to S ₁ in the differential pulse wave A) to the third crossing point X ₃ (differential pulse wave). It is a first to third intersection required time detecting unit for detecting a required time T _X13 (corresponding to S ₃ in A) (corresponding to T _S13 in the differential pulse wave A). Reference numeral 15 in FIG. 7 indicates the time T _X23 (T in the differential pulse wave A) from the second _cross point X ₂ (corresponding to S ₂ in the differential pulse wave A) obtained by the cross point detection unit 13 to the third intersection X _{3. It} is a second to third intersection required time detecting unit for detecting (equivalent to _S23 ).

According to this configuration, the rising point S ₁ , the maximum point S ₂ , and the slope 0 point S ₃ of the waveform A to be detected in the configurations of FIGS. 1 and 5 are all twice uniformly differentiated. The intersections X ₁ , X ₂ , and X ₃ of A ′ with the reference line X can be easily and surely detected by the same detection method (intersection detector 13).

Here, a little supplementary explanation will be added on the medical significance of the present invention. Generally, the pulse wave is widely used as a means for detecting blood circulation in the human body, and the differential pulse wave waveform obtained by differentiating the pulse wave has a plurality of peaks as shown in the upper part of FIG. 2 or 3. It is known that the waveform has a waveform corresponding to the flow velocity of blood at the measurement site. The first occurrence mountain i.e. differentiated first wave waveform (S ₁ to S ₃₎
Shows the process in which the blood pressure at the measurement site is expanded by the blood's blood pushing force, the blood flow velocity increases, and then the elasticity of the blood vessel slows it down. It is considered to be an attenuation waveform due to the influence of vascular elasticity.

Therefore, the time required for the first differential wave (T
_S13 ) is a value that serves as an index that comprehensively represents the blood pushing force of the heart and the elasticity of blood vessels, and the time required for deceleration of the first differential wave, that is, the time required for the differential wave descent (T
_S23 ) is mainly an index that characterizes the elasticity of blood vessels and is extremely important medically.

[0028]

As is apparent from the above description, the pulse wave measuring device of the present invention requires the first wave of the differential pulse wave which is considered to have a deep relation to both the blood pushing force of the heart and the elasticity of the blood vessel. The time or differential wave descent time can be easily obtained by measuring the time intervals of the characteristic 3 points represented by the rising point, maximum point, and slope of 0 points of the waveform. It is possible to evaluate various blood circulation conditions,
A great medical effect can be expected.

Further, as a concrete detecting means of the rising point, the maximum point, and the slope 0 point of the waveform, the method of detecting the intersection of the double differential pulse wave and the reference line is used to make the measurement simpler and more reliable. It is possible to provide a practical method for obtaining results.

Further, since the obtained measurement result can be corrected and calculated to a value corresponding to the measurement at a predetermined reference pulse rate by using the pulse rate of the subject, the variation of the evaluation caused by the fluctuation of the pulse rate can be eliminated. In addition, it is possible to absorb individual differences due to differences in subjects, and it is possible to uniformly compare and evaluate all measurement results.

[Brief description of drawings]

FIG. 1 is a block configuration diagram of a pulse wave measuring device according to an embodiment of the present invention.

FIG. 2 is a waveform diagram showing an example of a differential pulse wave and a second differential pulse wave for explaining the basic operation of the pulse wave measuring device.

FIG. 3 is a waveform diagram showing another example of the differential pulse wave and the second differential pulse wave for explaining the basic operation of the pulse wave measuring device.

FIG. 4 is a waveform diagram of a differential pulse wave for explaining the operation of pulse rate correction calculation by the pulse wave measuring device.

FIG. 5 is a block configuration diagram of a pulse wave measuring device according to the second embodiment.

FIG. 6 is a block diagram of a pulse wave measuring device according to the third embodiment.

FIG. 7 is a block configuration diagram of a pulse wave measuring device according to the fourth embodiment.

FIG. 8 is a waveform diagram of an acceleration pulse wave waveform for explaining an index calculation method of a conventional pulse wave measuring device.

[Explanation of symbols]

 1 pulse wave sensor 2 differential processing unit 3 rising point detection unit 4 slope 0 point detection unit 5 differential first wave required time detection unit 6 pulse rate detection unit 7 pulse rate correction calculation unit 10 maximum point detection unit 11 differential wave fall required time Detecting unit 12 Two-time differential processing unit 13 Intersection detecting unit 14 First to third intersection required time detecting unit 15 Second to third intersection required time detecting unit

Claims (5)

[Claims] 1. A pulse wave sensor for detecting an increase or decrease in blood volume such as a fingertip or an earlobe, a differential processing section for differentially processing the output of the pulse wave sensor, and a temporal position of a rising point of a waveform obtained by the differential. A rising point detecting section for detecting, a slope 0 point detecting section for detecting a temporal position of a point where the rising waveform decreases after passing the maximum point and the slope becomes 0, and until the slope reaches 0 point from the rising point Pulse wave measuring apparatus having a differential first wave required time detecting section for detecting the required time of the above. 2. A pulse wave sensor for detecting an increase / decrease in blood volume of a fingertip, an earlobe, etc., a differential processing section for differentially processing the output of the pulse wave sensor, and the maximum value after the waveform obtained by the differential rises. A maximum point detecting section for detecting the temporal position of the point, and a slope 0 point detecting section for detecting the temporal position of the point which decreases after passing the maximum point and has a slope of 0, and a slope from the maximum point. A pulse wave measuring device comprising: a differential wave fall required time detecting unit that detects a time required for the waveform to fall until reaching 0 point. 3. A pulse wave sensor for detecting an increase / decrease in blood volume of a fingertip, an earlobe, etc., a double differentiation processing section for differentially processing the output of the pulse wave sensor twice, and a waveform obtained by the double differentiation is a reference. An intersection point detection unit that detects the temporal position of a point that intersects the line, and first to first times that detect the time required from the first intersection point (the rising point of the waveform) of the waveform obtained by this intersection point detection unit to the third intersection point. A pulse wave measuring device including a three-intersection required time detecting unit. 4. A pulse wave sensor for detecting an increase / decrease in blood volume of a fingertip, an earlobe, etc., a two-time differential processing section for differentially processing the output of the pulse wave sensor twice, and a waveform obtained by the two-time differential is a reference. An intersection detection unit that detects the temporal position of a point that intersects the line, and a second to third intersection required time detection that detects the time required from the second intersection to the third intersection of the waveform obtained by this intersection detection unit. And a pulse wave measuring device. 5. A pulse rate detection unit for counting the pulse rate of a subject is provided, and the first derivative is based on the pulse rate obtained by the pulse rate detection unit.
Wave required time, or differential wave descent required time, or first to
A pulse rate correction calculator for correcting the values of the three intersection points required time or the values of the second to third intersection points required time to a value corresponding to the measurement at a predetermined reference pulse rate (for example, 60 beats / minute) was provided. The pulse wave measuring device according to any one of claims 1 to 4.