JP3533129B2 - Non-invasive continuous sphygmomanometer - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-invasive continuous sphygmomanometer, and more particularly to continuous blood pressure by applying weak vibration to a blood vessel in a living body and detecting and analyzing the vibration propagating in the blood vessel. The present invention relates to a non-invasive continuous blood pressure monitor.

[0002]

2. Description of the Related Art Conventionally, as a non-invasive and continuous method for measuring blood pressure, a method disclosed in Japanese Patent Publication No. 9-506024 is known. This is to calculate the elasticity of the blood vessel by detecting the propagation velocity of the signal in the blood vessel by utilizing the fact that the elasticity of the blood vessel changes according to the change in blood pressure.
The blood pressure is estimated from the elasticity of the blood vessel. The outline of the processing is as follows.

A blood vessel is vibrated from the body surface of a subject, and the vibration propagated on the blood vessel is detected. After converting the detected vibration into a digital signal, filtering processing and phase detection processing are performed. The phase-detected signal is I (real number) component and Q
(Imaginary number) component is separated. At this time, theoretically,
The detected signal plotted on the IQ plane draws an arc centering on a certain point, and the point on the arc seen from this center point, that is, the detected signal on the IQ plane The change in position is the change in vibration propagation velocity due to blood pressure fluctuation. The change in vibration propagation velocity represents a change in blood vessel elasticity, and the change in blood vessel elasticity represents a change in blood pressure, that is, dynamic pressure.

In the invention disclosed in Japanese Patent Publication No. 9-506024, the relative change of the blood pressure value is calculated by estimating the center point of the arc formed on the IQ plane by the detected signal. I have to. By calibrating this relative change with the measurement values of the systolic blood pressure and the diastolic blood pressure, which are separately set for the same subject, the blood pressure in the living body is measured non-invasively and continuously. The measured blood pressure waveform is displayed along with biological information waveforms such as an electrocardiogram, a respiratory curve, and oxygen saturation while sweeping on the same monitor.

[0005]

However, the accuracy of blood pressure measurement in the invention disclosed in the above Japanese Patent Publication No. 9-506024 is greatly influenced by the center point of the arc estimated on the IQ plane. Will end up. During blood pressure measurement, if the center of the arc is not correctly estimated, an incorrect blood pressure waveform will be displayed. In such a case, in the invention disclosed in Japanese Patent Publication No. 9-506024, since the IQ plane is not displayed on the monitor, whether or not the blood pressure value is correctly measured only by looking at the blood pressure waveform, that is, There is a problem that it may be difficult to judge whether the center point of the arc is correctly estimated.

The present invention has been made to solve the above-mentioned conventional problems, and provides a non-invasive continuous blood pressure monitor with high accuracy and high reliability.

[0007]

In the non-invasive continuous blood pressure monitor of the present invention, the vibrating means for vibrating the blood vessel, the vibration detecting means for detecting the vibration propagating through the blood vessel, and the vibration detecting means detect the vibration. Phase detection means for phase-detecting the electrical signal obtained from the vibration to obtain a phase detection signal, and blood pressure calculation for continuously and non-invasively measuring the blood pressure by analyzing the phase detection signal obtained by the phase detection means And a detection signal display means for displaying the phase detection signal. With this configuration, the reliability of the blood pressure waveform is determined by displaying the phase-detected signal,
The accuracy can be estimated.

In the non-invasive continuous sphygmomanometer according to the present invention, the phase detection signal displayed on the detection signal display means is displayed on a two-dimensional plane by the imaginary component and the real number component of the phase detection signal obtained by the phase detection means. It has a configuration of a plurality of points represented and a center point of an arc formed by the plurality of points represented on a two-dimensional plane. With this configuration, the displayed phase detection signal is displayed by a plurality of points represented on the two-dimensional plane by the imaginary number component and the real number component, and the center point of the arc formed by the plurality of points. Thus, the reliability of the blood pressure waveform can be easily determined.

The non-invasive continuous sphygmomanometer according to the present invention comprises arc center setting means for setting the center point of the arc displayed on the detection signal display means and input means for inputting the center of the arc to the arc center setting means. And the configuration is such that the center point of the currently displayed arc is manually input and changed by the input means. With this configuration, by manually changing the center point of the displayed arc,
When it is determined by the operator's judgment that the phase detection signal is not correctly analyzed, the operator can easily change and set the center point of the arc manually.

In the non-invasive continuous sphygmomanometer of the present invention, the input means for inputting the center of the arc to the arc center setting means,
It has a configuration of a mouse, a trackball, or a touch panel. With this configuration, the center point of the arc can be set by a general mouse, trackball or touch panel without using a special device, so that the center point of the arc can be changed and set easily at low cost. It will be possible.

The non-invasive continuous sphygmomanometer according to the present invention has a construction including detection signal output means for outputting the phase detection signal obtained by the phase detection means to an external monitor device. With this configuration, the phase detection signal is output to the external monitor device for display, so that convenience in display can be improved.

The non-invasive continuous sphygmomanometer of the present invention has a structure in which the external monitor device is a computer having a display means. With this configuration, the phase detection signal is output to the computer for display without using a special device, so that the display means can be selected according to the operator's preference.

[0013]

DETAILED DESCRIPTION OF THE INVENTION Referring to FIGS.
The non-invasive continuous blood pressure monitor according to the first embodiment of the present invention will be described. FIG. 1 is a block diagram showing the configuration of a non-invasive continuous blood pressure monitor according to the first embodiment of the present invention.

In FIG. 1, a D / A converter 5 D / A converts a signal from a microprocessor (hereinafter referred to as MPU) 6 for driving the shaker 1 and sends the signal to the shaker 1.
The vibrator 1 induces vibration on the artery of the living body by the signal, and the detector 2 detects the vibration induced on the artery by the vibrator 1. The vibration signal detected by the detector 2 is amplified by the amplifier 3. The vibration signal amplified by the amplifier 3 is A / D converted by the A / D converter 4. The MPU 6 is a microprocessor that executes various calculations based on the data input from the A / D converter 4. While the cuff band 7 is attached to a part of a living body and pressed, the cuff control unit 8 drives the cuff band 7 to measure the maximum, minimum, and average blood pressure during one heartbeat in a non-invasive manner.
Then, the monitor 9 as the detection signal display means displays the blood pressure waveform and the phase-detected signal and data.

The mouse 10 has a function as an input means of the arc center setting means, and the center point of the arc is manually moved by moving the cursor, and the button 11 attached to the mouse 10 is pushed to move the center of the arc. Used to set points manually. Further, the MPU 6 represents a phase detection means for inputting the vibration signal detected by the detector 2 to perform phase detection and output a phase detection signal, and a continuous change in the blood pressure value of the human body based on the phase detected signal. It has a blood pressure calculating means for calculating a continuous blood pressure value and an arc center setting means for correcting or setting the center point of the arc displayed on the detection signal display means.

Next, the operation of the non-invasive continuous blood pressure monitor according to the first embodiment of the present invention will be described with reference to FIG.
First, the MPU 6 starts the excitation waveform Asin (2πf
generate t). The excitation waveform Asin (2πft) generated by the MPU 6 is D / A converted by the D / A converter 5.
To be converted. The shaker 1 is D / A converted by the D / A converter 5.
The transformed excitation waveform is induced on the blood vessel. The detector 2 detects the vibration induced by the vibrator 1 and propagating on the blood vessel wall. The vibration detected by the detector 2 is amplified by the amplifier 3, A / D converted by the A / D converter 4, and input to the MPU 6.

Next, referring to FIGS. 1 and 2, the MPU of the non-invasive continuous blood pressure monitor according to the first embodiment of the present invention continuously changes the blood pressure from the input of the vibration signal detected by the detector. A calculation procedure for obtaining a change will be described. (For example,
The method as described in Japanese Patent Publication No. 9-506024 can be used. ) The MPU 6 performs step S as shown in FIG. 2 on the input vibration signal W (t).
The three-step processing of 101 to S103 is executed.

First, in step S101, the vibration signal W (t) is phase-detected by the phase detection means of the MPU 6 by a method known as quadrature detection, and Si (I component) corresponding to the phase change is detected. t) and the imaginary component (Q
Sq (t) which is a component) is calculated (t is time). Next, in step S102, step S1
The center point (Ci, Cq) of the arc formed on the IQ plane is estimated from the I component Si (t) and the Q component Sq (t) of the phase detection signal obtained in 01.

In step S103, the blood pressure calculation means of the MPU 6 calculates the angle θ (t) of Si (t) and Sq (t) viewed from the center point (Ci, Cq) of the arc as shown in FIG. Calculate from the following formula. θ (t) = arctan ((Sq (t) −Cq) / (S
i (t) -Ci)) This θ (t) represents a continuous change of the blood pressure value, and θ (t)
By calibrating (t) with at least any two of the systolic blood pressure value, the mean blood pressure value and the diastolic blood pressure value measured by the cuff band 7 and the cuff control unit 8, the continuous blood pressure value P ( t) is calculated (t is time).

The calculated continuous blood pressure value P (t) is swept and displayed as a time series waveform on the blood pressure waveform display screen 41 of the monitor 9 shown in FIG. Further, in the first embodiment of the present invention, the monitor 9 uses the steps S101 and S102.
It is possible to display Si (t), Sq (t) and the center point (Ci, Cq) of the arc calculated on the arc display screen 42.

If it can be determined that the center point of the arc displayed on the monitor 9 and estimated in step S102 of FIG. 2 is not clearly measured correctly as shown in FIG. Center point of the arc (C
i, Cq) can be set manually.

Now, referring to FIG. 6, the center point (C
The manual setting of i, Cq) will be described. As shown in FIG. 6, a cursor is displayed on the arc display screen 42 on which the IQ plane is displayed, and the position of the cursor is determined by using the mouse 10 as in a computer having a general graphical user interface. , The arc center setting means of the MPU 6 judges that the position is the center point of the arc by pressing the button 11 to calculate the blood pressure value. As the input means of the arc center setting means, other input means such as a trackball may be used instead of the mouse 10.

The arc display screen 42 is a touch panel. When the operator touches a position on the screen desired to be set as the center of the arc with a finger or a touch pen, the position of the arc is changed in the same manner as the mouse 10. The blood pressure value can be calculated by determining that it is the center point of the blood pressure.

Next, a non-invasive continuous blood pressure monitor according to the second embodiment of the present invention will be described with reference to FIGS. FIG. 7 is a block diagram showing the configuration of a non-invasive continuous blood pressure monitor according to the second embodiment of the present invention, and FIG. 8 is an enlarged view of a computer having the blood pressure waveform display screen and the arc display screen shown in FIG. 7, components having the same numbers as the numbers given in FIG. 1 have the same name and the same function, and therefore the description thereof will be omitted.

7 and 8, in the present embodiment, a computer 12 is used as an external monitor device instead of the monitor 9 in the first embodiment, and this computer 12 is a general one. Often, a display unit is provided to display the blood pressure waveform and the phase-detected signal in the same manner as the monitor 9 in the first embodiment. The serial port 13 functions as a detection signal output unit for the computer 12, and also has a function as an interface for inputting the data or signal output from the MPU 6 to the computer 12. Further, the blood pressure waveform display screen 81 displays the continuous blood pressure value P (t) as a time series waveform,
The arc display screen 82 displays Si (t), Sq (t) and the center points (Ci, Cq) of the arc.

Next, the operation of the non-invasive continuous blood pressure monitor according to the second embodiment of the present invention will be described with reference to FIGS. 7 and 8. The MPU 6 is similar to that of the first embodiment in FIG.
By the processing of steps S101 to S103 shown in
i (t), Sq (t), the center point (Ci, Cq) of the arc, and the continuous blood pressure value P (t) are calculated (t is the time). The calculated Si (t), Sq (t), (Ci,
Cq) and P (t) are output to the computer 12 as serial data. The computer 12 sends Si (t), Sq (t), (C
i, Cq) and P (t) data are received.
As shown in FIG.
1, the continuous blood pressure value P (t) is swept and displayed as a time series waveform, and S is also displayed on the arc display screen 82 of the computer 12.
Display i (t), Sq (t) and (Ci, Cq).

Also in the present embodiment, as in the first embodiment, the arc display screen 8 of the computer 12 is displayed.
When it can be determined that the center point of the circular arc displayed on 2 is not clearly measured correctly as shown in FIG. 5,
The operator uses the mouse 1 as an input means of the arc center setting means.
0 (or a trackball or a touch panel), the center point (Ci, Cq) of the arc is manually moved to a position to be set as the arc center, and the button 11 is pressed to cause the arc center setting means of the MPU 6 to The position is determined to be the center point of the arc, the position setting is corrected, and the blood pressure value is calculated. In the present embodiment, as described above, by using a computer that is widely used, it is possible to easily and inexpensively realize a non-invasive continuous blood pressure monitor. The above computer may be another information terminal having an image display unit and an input unit.

[0028]

The non-invasive continuous sphygmomanometer according to the present invention can display the phase-detected signal, so that the reliability of the blood pressure waveform, which is difficult to understand only by looking at the blood pressure waveform, is more accurate. It can be estimated, and the measurement accuracy and reliability of the non-invasive continuous blood pressure monitor can be improved.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of a non-invasive continuous blood pressure monitor according to a first embodiment of the present invention,

FIG. 2 is a flowchart illustrating a processing procedure of the MPU shown in FIG.

3 is Si (t), Sq viewed from a center point (Ci, Cq) of an arc calculated by the arithmetic processing of the MPU shown in FIG.
A diagram showing an angle θ (t) of (t),

4 is a front view of the monitor shown in FIG.

5 is a diagram of a monitor display screen when it is determined that the center point of the arc displayed on the monitor shown in FIG. 4 is not correct;

6 is a diagram showing how the center point of an arc is manually set by the mouse shown in FIG. 1;

FIG. 7 is a block diagram showing a configuration of a non-invasive continuous sphygmomanometer according to a second embodiment of the present invention,

8 is an enlarged view of a computer having a blood pressure waveform display screen and an arc display screen shown in FIG.

[Explanation of symbols]

1 shaker 2 detector 3 amplifier 4 A / D converter 5 D / A converter 6 MPU 7 cuff belt 8 cuff control unit 9 monitors 10 mice 11 buttons 12 computers 13 serial port 41, 81 Blood pressure waveform display screen 42, 82 arc display screen 101 Quadrature detection step 102 Arc center estimation step 103 Blood Pressure Change Calculation Step

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-11-276446 (JP, A) JP-A-10-179527 (JP, A) JP-A-2001-112726 (JP, A) JP-A-9-506024 (JP, A) (58) Fields surveyed (Int.Cl. ⁷ , DB name) A61B 5/02-5/03 A61B 8/00-8/12

Claims (6)

(57) [Claims] 1. A vibrating means for vibrating a blood vessel, a vibration detecting means for detecting a vibration propagating in a blood vessel, and a phase detection by phase-detecting an electric signal obtained from the vibration detected by the vibration detecting means. Phase detection means for obtaining a signal, blood pressure calculation means for continuously and noninvasively measuring blood pressure by analyzing the phase detection signal obtained by the phase detection means, and detection signal display for displaying the phase detection signal A non-invasive continuous sphygmomanometer comprising: 2. The phase detection signal displayed on the detection signal display means includes a plurality of points represented on a two-dimensional plane by an imaginary number component and a real number component of the phase detection signal obtained by the phase detection means, The non-invasive continuous blood pressure monitor according to claim 1, which is a center point of an arc formed by a plurality of points represented on the two-dimensional plane. 3. An arc center setting means for setting the center point of the arc displayed on the detection signal display means, and an input means for inputting the center of the arc to the arc center setting means, which are currently displayed. The non-invasive continuous blood pressure monitor according to claim 2, wherein the center point of the curved arc is manually input and changed by the input means. 4. The non-invasive continuous blood pressure monitor according to claim 3, wherein the input means for inputting the center of the arc to the arc center setting means is a mouse, a trackball or a touch panel. 5. The non-invasive continuous apparatus according to claim 1, further comprising detection signal output means for outputting the phase detection signal obtained by the phase detection means to an external monitor device. Sphygmomanometer. 6. The non-invasive continuous blood pressure monitor according to claim 5, wherein the external monitor device is a computer having display means.