JPH119562A - Blood vessel tracking type continuously blood pressure monitoring apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a blood vessel tracking type continuously pressure monitoring apparatus which enables continuation of monitoring a blood pressure by eliminating any deviation of an artery quickly even when the deviation of the artery is caused under the pressing by a pressure pulse wave sensor during the continuously monitoring of the blood pressure. SOLUTION: During the continuously monitoring of a blood pressure using an estimated blood pressure, when the deviation of a radial artery is determined by an artery deviation judging means 82 to occur from a pressing surface of a pulse wave sensor 46, the pulse wave sensor 46 is moved to a width-wise moving device 64 by a pressing force position correcting means 84 so that the positional deviation of the pulse wave sensor 46 is reduced with the pressing force of the pressure pulse wave sensor 46 maintained at the optimum value by an optimum pressing force control means 80. This can eliminates the positional deviation of the radial artery from a reference position such as a center position pressure detector on the pressing surface of the pressure pulse wave sensor 46 without activating the optimum pressing force position checking action or the optimum pressing force determining action, thereby achieving a quick continuation of monitoring a blood pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for continuously monitoring the blood pressure of a living body and tracking the artery which is depressed and moved by a pressure pulse wave sensor. The present invention relates to a continuous blood pressure monitoring device of a pressing type.

[0002]

2. Description of the Related Art A pressure pulse wave sensor having a plurality of pressure detecting elements arranged in the width direction of an artery on a pressing surface for detecting a pressure pulse wave generated from an artery of a living body, and the pressure pulse wave sensor A pressing device that presses toward the artery, a width direction moving device that moves the pressure pulse wave sensor in the width direction to change the pressing position where the pressure pulse wave sensor is pressed in the width direction of the artery, Optimal pressing position control means for positioning the pressure pulse wave sensor at a position immediately above the artery by the width direction moving device based on the pressure pulse wave detected by the pressure pulse wave sensor; and a blood vessel of the artery by the pressing device. Optimum pressing force control means for pressing the pressure pulse wave sensor with an optimum pressing force at which a part of the wall becomes substantially flat and maintaining the optimum pressing force; and detecting pressure of the pressure pulse wave sensor from a preset relationship. Detected by the element Estimated blood pressure value determining means for sequentially determining an estimated blood pressure value of the living body based on the magnitude of the pressure pulse wave, and a continuous blood pressure monitoring device that continuously monitors the blood pressure value of the living body based on the estimated blood pressure value. Are known. For example, this is a continuous blood pressure monitoring device described in Japanese Patent Application Laid-Open No. 8-187230.

[0003]

By the way, the artery which is pushed toward the inside of the living body by the pressing of the pressure pulse wave sensor is caused by the inclination of the pressing surface of the pressure pulse wave sensor due to body movement or the like. The artery may suddenly shift with respect to the pressing surface of the pressure pulse wave sensor during continuous blood pressure monitoring due to body movement or contact with the pressure pulse wave sensor because it easily moves to the outside of the pressing surface. For this reason, in the conventional continuous blood pressure monitoring device, the pressing of the pressure pulse wave sensor is stopped by separating the pressure pulse wave sensor from the skin of the living body by activating the optimum pressing position confirmation operation and the optimum pressing force determining operation, and then the pressure pulse is detected. By slightly moving the wave sensor to the moving side of the blood vessel and pressing it again, the optimum pressing position is confirmed or the optimum pressing position is determined. For this reason, there has been an inconvenience that the continuous blood pressure monitoring is interrupted during a period in which the operation of confirming the optimal pressing position and the operation of determining the optimal pressing force are performed.

The present invention has been made in view of the above circumstances, and an object of the present invention is to quickly remove an artery that is depressed by a pressure pulse wave sensor during continuous blood pressure monitoring. An object of the present invention is to provide a blood vessel tracking type continuous blood pressure monitoring device in which a deviation is eliminated and continuous blood pressure monitoring is continued.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above object, the gist of the present invention is to detect a plurality of pressure pulses generated from an artery of a living body. A pressure pulse wave sensor having a pressure detecting element on a pressing surface, a pressing device for pressing the pressure pulse wave sensor toward the artery, and a pressing position where the pressure pulse wave sensor is pressed is changed in a width direction of the artery. A width direction moving device for moving the pressure pulse wave sensor in the width direction in order to move the pressure pulse wave sensor based on the pressure pulse wave detected by the pressure pulse wave sensor. An optimal pressing position control means for positioning the pressure pulse wave sensor by the pressing device with an optimal pressing force set in advance so that a part of the blood vessel wall of the artery is substantially flat, and Maintain pressing force An optimal pressure control means for determining an estimated blood pressure value for sequentially determining an estimated blood pressure value of the living body based on the magnitude of the pressure pulse wave detected by the pressure detecting element of the pressure pulse wave sensor from a preset relationship. A continuous blood pressure monitoring device that continuously monitors the blood pressure value of the living body based on the estimated blood pressure value, wherein (a) the pressing force of the pressure pulse wave sensor is optimized by the optimal pressing force control means. An arterial misalignment determination for determining a misalignment of the artery with respect to a reference position of a pressure surface of the pressure pulse wave sensor in a state where the pressure is maintained at the pressing force and the estimated blood pressure value of the living body is sequentially determined by the estimated blood pressure value determining means. And (b) when the arterial displacement determining means determines that the artery is displaced from the pressing surface of the pulse wave sensor, the optimal pressing force control means reduces the pressure of the pressure pulse wave sensor to the maximum. And a pressing position correcting means for moving the pulse wave sensor to the width direction moving device so as to reduce the displacement of the artery while maintaining the proper pressing force.

[0006]

In this way, during continuous blood pressure monitoring based on the estimated blood pressure, if the arterial deviation determining means determines the deviation of the artery from the pressing surface of the pulse wave sensor, the pressed position is corrected. By means, by the width direction moving device so that the displacement of the pulse wave sensor is reduced while the pressing force of the pressure pulse wave sensor is maintained at the optimum pressing force by the optimum pressing force control means, The pulse wave sensor is moved. Therefore, the displacement of the pressure surface of the arterial pressure pulse wave sensor with respect to the reference position is eliminated without activating the optimal pressing position confirming operation or the optimal pressing force determining operation, and blood pressure monitoring is immediately continued. .

[0007]

In another aspect of the present invention, preferably, the estimated blood pressure value determining means includes a reference blood pressure measurement value measured using a cuff and a plurality of pressure detecting elements arranged on a pressing surface of the pressure pulse wave sensor. The center position pressure detection is performed based on a relationship determined in advance with the size of the pressure pulse wave detected by the center position pressure detection element that outputs the maximum pulse wave amplitude at a relatively low pressing force lower than the optimum pressing force. The estimated blood pressure value of the living body is sequentially determined based on the magnitude of the pressure pulse wave output from the element.

[0008] Preferably, the arterial displacement judging means is such that the pressing force of the pressure pulse wave sensor is maintained at the optimum pressing force by the optimum pressing force control means, and the estimated pressure of the living body is determined by the estimated blood pressure value determining means. In the state where the estimated blood pressure value is determined, based on the pressure pulse waves detected by the plurality of pressure detection elements of the pressure pulse wave sensor, the amplitude axis indicating the amplitude of the pressure pulse wave and the position of the pressure detection element A two-dimensional coordinate with a position axis indicating the relationship between the amplitude of the pressure pulse wave and the position of the pressure detecting element is obtained, and an amplitude distribution curve or tonogram on the pressing surface is obtained, and a preset center of the amplitude distribution curve is determined. The displacement of the artery relative to a reference position of the pressing surface of the artery is determined based on the symmetry about the line.

Preferably, the arterial deviation judging means is provided by a change state of each of a pair of areas of a predetermined section on both sides of the center line in the amplitude distribution curve, for example, by the optimum pressing force control means. The difference between a pair of areas S _L and S _R of predetermined sections on both sides of the center line in the amplitude distribution curve when the pressure pulse wave sensor is pressed with the optimum pressing force by the pressing device, or a pair of these areas S _L and S change ratio of _R [Delta] S _L / S _L and [Delta] S _R /
The difference between S _R or the area increase ΔS _L and ΔS of the predetermined section on both sides of the center line in the actual amplitude distribution curve.
_This is to determine the deviation of the artery based on the ratio of _R.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a diagram showing an example of the configuration of a continuous blood pressure monitoring apparatus according to the present invention. The apparatus is used for monitoring the condition of a patient during and after an operation, a living body during an exercise load test, and the like. Can be In the drawing, reference numeral 10 denotes a cuff having a rubber bag in a cloth band-shaped bag, which is mounted, for example, in a state of being wound around the upper arm 12 of a patient. A pressure sensor 14, an exhaust control valve 16, and an air pump 18 are connected to the cuff 10 via a pipe 20, respectively. Exhaust control valve 16
Switches between three states: a pressure supply state in which the supply of pressure into the cuff 10 is permitted, a slow discharge state in which the cuff 10 is gradually discharged, and a rapid discharge state in which the cuff 10 is rapidly discharged. It is configured to be.

The pressure sensor 14 detects the pressure in the cuff 10 and outputs a pressure signal SP representing the pressure to the static pressure discriminating circuit 22.
And the pulse wave discrimination circuit 24. The static pressure discriminating circuit 22 includes a low-pass filter, and the pressure signal S
A cuff pressure signal SK representing a steady pressure included in P is discriminated, and the cuff pressure signal SK is supplied to the arithmetic and control unit 28 via the A / D converter 26. The pulse wave discrimination circuit 24 includes a band-pass filter, discriminates the pulse wave signal SM ₁ which is a vibration component of the pressure signal SP, and converts the pulse wave signal SM ₁ to A
It is supplied to the arithmetic and control unit 28 via the / D converter 30.
Cuff pulse wave which the pulse wave signal SM ₁ represents is generated from the brachial artery (not shown) in synchronization with the patient's heart is the pressure vibration wave transmitted to the cuff 10, the pulse-wave filter circuit 24 cuff-pulse-wave It functions as detection means.

The arithmetic and control unit 28 includes a CPU 29, R
The microcomputer 29 includes a so-called microcomputer including an OM 31, a RAM 33, an I / O port (not shown), and the like. The CPU 29 executes signal processing using the storage function of the RAM 33 according to a program stored in the ROM 31 in advance. As a result, a drive signal is output from the I / O port to control the exhaust control valve 16 and the air pump 18 via a drive circuit (not shown). When measuring the blood pressure using the cuff 10, for example, the pressure in the cuff 10 is rapidly increased to a predetermined target pressure, and then gradually reduced at a speed of about 3 mmHg / sec. The blood pressure values such as the systolic blood pressure value and the diastolic blood pressure value are determined by the oscillometric method based on the change of the pulse wave represented by the wave signal SM ₁ , and the determined blood pressure values are displayed on the display 32.

As shown in detail in FIG. 2, the pressure pulse wave detecting probe 34 has a case 37 for accommodating a sensor housing 36 in the form of a container, and a probe 37 for moving the sensor housing 36 in the width direction of the radial artery 56. And a screw shaft 41 screwed to the sensor housing 36 and rotationally driven by a motor (not shown) provided in a driving portion 39 of the case 37. The case 37 has a mounting band 4
In the state where the opening end of the container-shaped sensor housing 36 faces the body surface 38 of the human body, the mounting band 40 can be attached to and detached from the side where the cuff 10 is not wound, for example, the left wrist 42. It can be attached to. Inside the sensor housing 36, a pressure pulse wave sensor 46 is provided via a diaphragm 44 so as to be relatively movable and protrudable from an open end of the sensor housing 36.
A pressure chamber 48 is formed by the diaphragm 44 and the like. The pressure chamber 48 is supplied with pressurized air from an air pump 50 via a pressure regulating valve 52, whereby the pressure pulse wave sensor 46 has a pressing force corresponding to the pressure in the pressure chamber 48. It is pressed against the body surface 38. In this embodiment, the pressing force of the pressure pulse wave sensor 46 is indicated by the pressure in the pressure chamber 48 (unit: mmHg).

The sensor housing 36 and the diaphragm 44 constitute a pressing device 62 for pressing the pressure pulse wave sensor 46 toward the radial artery 56.
1 and a motor (not shown) are a pressing position changing device that changes a pressing position where the pressure pulse wave sensor 46 is pressed in the width direction of the radial artery 56, that is, a width direction moving device 6
4.

The pressure pulse wave sensor 46 has a pressing surface 54 made of a semiconductor chip made of, for example, single crystal silicon.
A large number of semiconductor pressure-sensitive elements (not shown) are arranged at regular intervals of about 0.2 mm in the width direction of the radial artery 56, that is, in the direction of movement of the pressure pulse wave sensor 46 parallel to the screw shaft 41. By being pressed onto the radial artery 56 on the body surface 38 of the wrist 42, a pressure vibration wave or pressure pulse wave generated from the radial artery 56 and transmitted to the body surface 38 is detected, and the pressure pulse wave is detected. The pressure pulse wave signal SM ₂ representing the pulse wave is supplied to the arithmetic and control unit 28 via the A / D converter 58. Figure 3 shows an example of a pressure pulse wave SM ₂ detected by the PPW sensor 46.

The CPU 29 of the arithmetic and control unit 28 has a ROM
31 according to a program stored in advance in the RAM 33.
The signal processing is executed while utilizing the memory function, and the air pump 5
0 and the pressure regulating valve 52 are driven via a drive circuit (not shown).
A signal is output to adjust the pressure in the pressure chamber 48. Arithmetic
For example, when monitoring the continuous blood pressure,
Based on the pressure pulse wave sequentially obtained during the slow pressure change process in the chamber 48,
To make a part of the blood vessel wall of the radial artery 56 substantially flat.
Pressure P of the pressure pulse wave sensor 46_HDPODetermine that
Optimal pressing force P_HDPOControl the pressure regulating valve 52 to maintain
You. The arithmetic and control unit 28 performs measurement using the cuff 10.
Systolic blood pressure BP_SYSAnd diastolic blood pressure BP
_DIAAnd the optimal pressing force P_HDPOPressure pulse while maintaining
Of the radial artery 56 of the semiconductor pressure-sensitive elements of the wave sensor 46
The center position pressure detection element (active element
The maximum value P of the pressure pulse wave detected by_Mmaxand
Minimum value P _MminValue BP and pressure pulse measured based on
Wave size P_M(Absolute value)
Are sequentially detected by the pressure pulse wave sensor 46 from the corresponding relationship
Pressure pulse wave size P_M(MmHg), that is, the highest value (upper peak
Value) P_MmaxAnd the lowest value (lower peak value) P_MminBased on
And systolic blood pressure MBP_SYSAnd diastolic blood pressure MBP _DIA
(Estimated blood pressure value, that is, monitor blood pressure value) is determined and displayed sequentially
Systolic blood pressure value MBP determined by the device 32_SYSAnd
And diastolic blood pressure MBP_DIAIs displayed numerically for each beat and estimated
A waveform indicating the blood pressure value MBP is displayed continuously.

The above-mentioned correspondence is, for example, as shown in FIG. In this equation 1,
A is a constant indicating the slope, and B is a constant indicating the intercept.

[0019]

[Number 1] MBP = A · P _M + B

FIG. 5 is a functional block diagram for explaining a main control function of the arithmetic and control unit 28 in the continuous blood pressure monitoring apparatus configured as described above. In the figure, the pressure sensor 14 detects the compression pressure of the cuff 10 that is changed by the cuff pressure control means 68 when measuring the blood pressure.
The blood pressure value measuring means 70 sets the compression pressure by the cuff 10 to 2
A systolic blood pressure value BP _SYS , a mean blood pressure value BP _MEAN , and a diastolic blood pressure value BP _DIA according to an oscillometric method based on a pulse synchronizing signal obtained in a process of gradually changing the speed at about 3 mmHg / sec, for example, a pulse wave amplitude. (Reference blood pressure value)
Is measured.

The relationship determining means 72 determines the magnitude P _{M of the} pressure pulse wave detected by the center position pressure detection element (active element) among the plurality of pressure detection elements arranged on the pressing surface 54 of the pressure pulse wave sensor 46. FIG. 4 shows the correspondence between the blood pressure value and the blood pressure value BP measured by the blood pressure value measuring means 70.
Is determined in advance as shown in FIG. Estimated blood pressure value determining means 74
Is the pressing surface 54 of the pressure pulse wave sensor 46 based on the corresponding relationship.
For example, the estimated blood pressure value MBP of the living body is continuously determined based on the magnitude of the pressure pulse wave detected by the center position pressure detection element among the plurality of pressure detection elements arranged in the above.

The optimum pressing position control means 76 determines that the position of the pressure pulse wave sensor 46 with respect to the radial artery 56 is largely shifted, and the pressure detecting element arranged on the pressing surface 54 which detects the maximum amplitude is the position of the array. When a predetermined pressing position update condition (APS activation condition) is satisfied, such as when the pressure pulse wave sensor 46 is located at the end, the pressing device 62 controls the pressure pulse wave sensor 46 to be sufficiently higher than the optimum pressing force. A pressure is applied with a relatively small first pressure value P ₁ which is set in advance, and in that state, one of the pressure detection elements of the pressure pulse wave sensor 46 which shows the maximum pulse wave amplitude is arranged in the arrangement direction of the pressure detection elements. It is determined whether or not it is located at a preset center.
If the judgment is negative, that is, if the pressure pulse wave sensor 46 is not located at the center, the pressure pulse wave sensor 46 is temporarily separated from the body surface 38 and the pressure pulse wave sensor 46 is moved, and then the above operation and judgment are executed again. I do. However, when the above determination is affirmative, that is, when the pressure detecting element of the pressure pulse wave sensor 46 that shows the maximum pulse wave amplitude is located at a predetermined central portion in the arrangement direction of the pressure detecting elements, Since the optimal pressing position has been obtained, the pressure detecting element that outputs the maximum pulse wave amplitude is set and stored as the central position pressure detecting element (active element), and the operation of the optimal pressing force control means 80 is performed. Allow.

The optimum pressing force control means 80 continuously changes the pressing force of the pressure pulse wave sensor 46 positioned at the optimum pressing position by the optimum pressing position control means 76, and obtains the pressure pulse wave obtained in the changing process. Is determined based on the pressure, and the pressure pulse wave sensor 46 is pressed by the optimum pressing force P _{HD PO} . The optimum pressing force P _HDPO is, for example, as shown in FIG. 6, a pressure within a predetermined range centered on the maximum value of the pulse wave amplitude obtained from the active element of the pressure pulse wave sensor 46 in the process of continuously increasing the pressing force. A curve connecting the lower peak value S _Mmin in the two-dimensional chart showing the value and / or the lower peak value S _Mmin of the pressure pulse wave signal SM ₂ obtained in the process of changing the pressing force and the pressing force of the pressure pulse wave sensor 46. The pressure value is within a predetermined range centered on the center of the flat portion formed in (dashed line in FIG. 6).

The arterial misalignment judging means 82 maintains the pressing force of the pressure pulse wave sensor 46 at the optimum pressing force by the optimum pressing force control means 80 and the estimated blood pressure value of the living body by the estimated blood pressure value determining means 74. The pressure surface 54 of the pressure pulse wave sensor 46 of the radial artery 56 is sequentially determined.
Is determined with respect to the reference position, for example, the center position. That is, based on the pressure pulse waves respectively detected by the pressure detecting elements of the pressure pulse wave sensor 46, the arterial displacement determining means 82 generates an amplitude axis (vertical axis) indicating the amplitude of the pressure pulse wave as shown in FIG. ) And a position axis (horizontal axis) indicating the position of the pressure detecting element, an amplitude distribution curve on the pressing surface 54 indicating the relationship between the amplitude of the pressure pulse wave and the position of the pressure detecting element is obtained. The optimal pressing position control means 7
6, centering on a preset center line of the amplitude distribution curve at the time of setting the optimum pressing position, that is, the center position of the pressure detecting element (active element) set by the optimum pressing position control means 76, and thereafter, actually The radial artery 5 based on the deviation of the symmetry of the obtained amplitude distribution curve
The position deviation of the No. 6 with respect to the pressing surface 54 is determined.
The amplitude distribution curve is also called a tonogram, and the amplitude decreases in inverse proportion to the distance from the radial artery 56. Therefore, the maximum position of the amplitude distribution curve substantially coincides with the center of the radial artery 56. There is nature.

For example, the arterial deviation judging means 82
Predetermined sections on both sides of the center line of the amplitude distribution curve
The state of change of each of the pair of areas between
Update of setting of optimal pressing position by appropriate pressing position control means 76
Amplitude distribution curve (base
Preset centerline of the quasi-tonogram)
Center position pressure set by optimal pressing position control means 76
Force detection element (active element)
A pair of areas S of a predetermined section_LAnd S_RChange in the difference
Is a pair of areas S_LAnd S_RChange rate ΔS_L/
S_LAnd ΔS _R/ S_RThe arterial displacement based on the
It is determined. The above ΔS_LAnd ΔS_RIs the actual
Predetermined sections on both sides of the center line in the amplitude distribution curve
Is the area change.

In the process of continuously measuring the estimated blood pressure by the estimated blood pressure value determining means 74, the pressed position correcting means 84 uses the arterial deviation determining means 82 to press the pressed surface 54 of the pulse wave sensor 46 of the radial artery 56. When the displacement is determined, the displacement of the radial artery 56 is reduced while the pressing force of the pressure pulse wave sensor 46 is maintained at the optimum pressing force by the optimum pressing force control means 80. That is, the pulse wave sensor 46 is moved by the width direction moving device 64 so that the center line of the actual amplitude distribution curve coincides with the preset center position pressure detecting element (active element) position.

FIGS. 8 and 9 are flow charts for explaining the main control operation of the arithmetic and control unit 28.
FIG. 9 shows a main routine, and FIG. 9 shows a pressing position correction control routine for correcting the pressing position of the pressure pulse wave sensor 46 while the operation of determining the estimated blood pressure is continuously performed.

In step S1 in FIG. 8 (hereinafter, the steps are omitted), it is determined whether or not S1 is the first execution, and the elapsed time since the last time the correspondence was updated is several ten minutes to several tens. It is determined whether or not the preset calibration cycle has been exceeded by about a minute. Normally, since the determination in S1 is denied, it is determined whether or not a predetermined pressing position update condition (APS activation condition) is satisfied in S2, for example, a pressure detecting element arranged on the pressing surface 54 of the pressure pulse wave sensor 46. It is determined whether or not the one for which the maximum amplitude is detected is located at the end of the array position.

If the pressure position of the pressure pulse wave sensor 46 on the radial artery 56 is within the normal range, the determination in S2 is negative, so that in S3, for example, the pressure pulse wave Based on whether a body motion that changes the pressing condition of the sensor 46 has been detected, or whether the monitored blood pressure value MBP has changed significantly with respect to the blood pressure value BP measured using the previous cuff 10 or the like. Then, it is determined whether or not a start condition for updating the correspondence for blood pressure monitoring, that is, an HDP start condition is satisfied.

If it is considered that there is no change in the pressing condition of the pressure pulse wave sensor 46 and the correspondence in FIG. 4 has not changed, the determination in S3 is negative, so that one pressure pulse wave is generated in S8. whether the not is determined based on the pressure pulse wave signal SM _2. If the determination at S8 is negative, S
The process is put on standby by repeatedly executing steps S1, S2, S3 and S8. However, if one pressure pulse wave is input and the judgment in S8 is affirmative, in S9 corresponding to the estimated blood pressure value determining means 74, the pressure pulse wave sensor 46 pressed with the optimum pressing force P _HDPO Pulse signal S from
From M _2, the maximum value P _Mmax and a minimum value P _Mmin of the wave
Is determined, and the maximum value P of the pressure pulse wave is obtained from the correspondence shown in FIG.
_Systolic blood pressure value MBP based on _Mmax and minimum value _PMmin
SYS and the diastolic blood pressure value MBP _DIA (estimated blood pressure value) are determined, and the determined estimated blood pressure value is sequentially displayed on the display 32 together with the continuous waveform of the estimated blood pressure value MBP for each beat.

While the above steps are repeatedly executed, if the time elapsed since the last time the correspondence was determined exceeds a preset calibration cycle, the above-described S1 is executed.
Is affirmative, the blood pressure measurement using the cuff 10 is executed in S6, the correspondence is updated in S7, and the above-mentioned S8 and thereafter are executed. That is,
First, in S6 corresponding to the blood pressure value measuring means 70, the exhaust control valve 16 is switched to the pressure supply state and the air pump 18 is operated to set the pressure in the cuff 10 to a target higher than the expected maximum blood pressure value of the patient. Pressure (eg 180mmHg)
After the pressure has been increased to a predetermined value, the air pump 18 is stopped and the exhaust control valve 16 is switched to the slow exhaust pressure state to lower the pressure in the cuff 10 at a predetermined slow pressure decreasing speed of about 3 mmHg / sec. The systolic blood pressure value BP _SYS and the average blood pressure value B are determined according to the well-known oscillometric blood pressure value determination algorithm based on the change in the amplitude of the pressure pulse wave represented by the pulse wave signal SM ₁ sequentially obtained in this slow pressure lowering process.
P _MEAN and a diastolic blood pressure value BP _DIA (reference blood pressure value) are measured, and a pulse rate and the like are determined based on the pulse wave interval. The measured blood pressure value and pulse rate are displayed on the display 32, and the exhaust control valve 1
6 is switched to the rapid exhaust pressure state, and the inside of the cuff 10 is quickly exhausted.

Next, S corresponding to the relation determining means 72
In 7, the pressure pulse wave pressure pulse wave magnitude from the sensor 46 (absolute value, that the pressure-pulse-wave signal SM size of ₂₎ and the blood pressure value BP _SYS using the cuff 10 as measured in the above S6, BP
The correspondence with the _DIA is determined and updated. That is, one pulse of the pressure pulse wave from the pressure pulse wave sensor 46 is read and the maximum value _PMmax and the minimum value _PMmin of the pressure pulse wave are determined, and the maximum value _PMmax and the minimum value of the pressure pulse wave are determined. Based on P _Mmin and the systolic blood pressure value BP _SYS and the diastolic blood pressure value BP _DIA measured by the cuff 10 at S6,
The correspondence between the magnitude of the pressure pulse wave and the blood pressure value shown in FIG. 4 is determined.

The pressing position of the pressure pulse wave sensor 46 with respect to the radial artery 56 is greatly displaced, and one of the pressure detecting elements arranged on the pressing surface 54 which detects the maximum amplitude is located at the end of the arrayed position. When the predetermined pressing position update condition is satisfied, such as when the pressing operation is performed, the determination in S2 is affirmative. Therefore, in the APS control routine of S4 corresponding to the optimum pressing position control means 76, FIG. The optimum pressing position for the center position pressure detecting element, which is the maximum amplitude position of the amplitude distribution curve, to be located substantially at the center of the pressing surface 54 is determined, and the center position pressure detecting element at that time is set as the active element. After the pressure pulse wave sensor 46 is positioned at the optimum pressing position, in the HDP control routine of S5 corresponding to the optimum pressing force control means 80, As position the center position the pressure pressing force maximum amplitude of the pressure pulse wave detected is obtained by the detection element is optimum pressing force P _HDPO right above the artery 56 in the process of pressing force of the pulse wave sensor 46 is continuously increased After being determined and updated, the pressing force of the pressure pulse wave sensor 46 becomes the optimum pressing force P
Held by _HDPO . Then, in a state where the pressure pulse wave sensor 46 is pressed by the optimum pressing force P _HDPO , the following S6 and subsequent steps are executed. On the other hand, if the determination in S2 is denied and the determination in S3 is affirmed, H in S5 is reached.
The following DP control routine is executed.

Hereinafter, in the above main routine, during the operation in which the pressing force of the pressure pulse wave sensor 46 is held at the optimum pressing force P _{HDPO and} the blood pressure value of the living body is continuously monitored, that is, S1, S2, S3 , S8, and S9 are repeatedly executed, and when the displacement of the radial artery 56 occurs, the moved radial artery 56 is tracked and the pressing position of the pressure pulse wave sensor 46 is corrected so as to eliminate the displacement. The pressing position correction control routine will be described with reference to FIG.

In SS1 in FIG. 9, it is determined whether or not the update of the correspondence shown in FIG. 4 (cuff calibration) has been executed in S7 corresponding to the relation determining means 72, or in S5 corresponding to the optimum pressing force control means 80. It is determined whether or not the optimum pressing force P _HDPO of the pressure pulse wave sensor 46 has been updated. When the determination at SS1 is denied, the pressing force of the pressure pulse wave sensor 46 is held at the optimum pressing force P _HDPO , and SS3 and subsequent steps are executed. However, if the determination in SS1 is affirmed, the reference amplitude distribution curve (reference tonogram) is stored in SS2, and the predetermined amplitudes on both sides of the center line of the reference amplitude distribution curve are sandwiched as shown in FIG. The areas S _L and S _{R of the} region are calculated.

Next, in SS3, in order to remove the fluctuation value, an averaging operation of the amplitude distribution curve (tonogram) obtained for each beat from the previous deviation determination to that time is executed, and the averaging operation is performed within a predetermined time. An averaged amplitude distribution curve (average tonogram) is obtained. Then, in SS4, whether contents "N" number of beats counter CN for counting the number of beats it has become a preset determination reference value N _M or more is determined. This determination reference value N _M corresponds to the shift determination cycle, and is set to a value corresponding to several beats to over a dozen beats. This S
In S4, it may be determined whether or not the elapsed time since the previous deviation determination has reached a predetermined reference time.

Initially, the determination at SS4 is denied, so that at step SS5, the content "N"
After "1" is added to the above, SS3 and subsequent steps are executed again. Then, while the above SS3 to SS5 are repeatedly executed, if the judgment of the above SS4 is affirmed, in SS6 corresponding to the arterial deviation determining means 82, the area change Δ of the average amplitude distribution curve with respect to the reference amplitude distribution curve is obtained.
S _L and ΔS _R are calculated, respectively, and the difference (ΔS _L / S _R / S _R between the area change rates ΔS _L / S _L and ΔS _R / S _R within a predetermined range on the left and right of the center line of the reference amplitude distribution curve.
S _L) - based on (ΔS _R / S _R), whether or not shift with respect to the pressing surface 54 of the pulse wave sensor 46 of the radial artery 56 has occurred is determined.

For example, the difference (ΔS _L / S _L ) −
If (ΔS _R / S _R ) is zero or a value close to zero, the determination in SS6 above is denied, and in SS7, the pressing position of the pulse wave sensor 46 in the direction crossing the radial artery 56 is the previous position. Is held. However, the difference (ΔS _L
If / S _L ) − (ΔS _R / S _R ) is a positive value or a negative value greater than or equal to a preset absolute value, the above SS6
Therefore, in SS8 corresponding to the pressing position correcting means 84, the optimum pressing force controlling means 80 (S
5), while the pressing force of the pressure pulse wave sensor 46 is maintained at the optimum pressing force, the pulse wave sensor 46 is displaced from the radial artery 56 with respect to the pressing surface 54 of the pulse wave sensor 46 by the width direction moving device 64. Is moved by a predetermined value in the direction in which the distance decreases. For example, the difference (ΔS _L / S _L ) − (ΔS
_{When R} / S _R ) is positive, the pulse wave sensor 46 is moved to the left side, that is, to the radial side, but when it is negative, the pulse wave sensor 46 is moved to the right side, that is, to the tendon side. is there.

As described above, according to this embodiment, during continuous blood pressure monitoring using the estimated blood pressure, the pulse wave sensor 4 of the radial artery 56 is determined by the arterial deviation determining means 82 (SS6).
When the deviation of the pressure pulse wave sensor 6 from the pressing surface 54 is determined, the pressing force of the pressure pulse wave sensor 46 is maintained at the optimum pressing force by the pressing position correcting means 84 (SS8) and the optimum pressing force control means 80 (S5). The pulse wave sensor 4
The pulse wave sensor 46 is moved by the width direction moving device 64 so as to reduce the displacement of 6. For this reason,
Since the optimum pressing position confirming operation and the optimum pressing force determining operation are not activated, the displacement of the pressing surface 54 of the pressure pulse wave sensor 46 of the radial artery 56 with respect to the reference position, for example, the center position pressure detecting element is eliminated. Blood pressure monitoring is continued immediately.

Further, according to the present embodiment, the arterial displacement judging means 82 (SS6) uses the optimum pressing force control means 80 (S6).
5) While the pressing force of the pressure pulse wave sensor 46 is maintained at the optimum pressing force and the estimated blood pressure value of the living body is determined by the estimated blood pressure value determining means 74 (S9), the plurality of pressure pulse wave sensors 46 Based on the pressure pulse wave detected by the pressure detecting element, the two-dimensional coordinates (FIG. 7) of the amplitude axis indicating the amplitude of the pressure pulse wave and the position axis indicating the position of the pressure detecting element are used. An amplitude distribution curve or tonogram on the pressing surface 54 showing the relationship between the amplitude of the pulse wave and the position of the pressure detecting element is obtained, and the artery of the artery is determined based on the symmetry of the amplitude distribution curve about a predetermined center line. The displacement of the pressing surface with respect to the reference position is determined. More specifically, the arterial misalignment determination means 82 (SS6) determines a change state of each of a pair of areas of a predetermined section on both sides of the center line in the amplitude distribution curve, for example, the optimal pressing force control means 80. the (S5), the average rate of change of the pair of areas S _L and S _R of a predetermined interval on both sides sandwiching the center line in the amplitude distribution curve when the pressure-pulse-wave sensor 46 is pressed at the optimum pressing force by the pressing device 62 The arterial deviation is determined based on the difference between ΔS _L / S _L and ΔS _R / S _R. Therefore, there is an advantage that the displacement of the radial artery 56 can be determined relatively accurately and easily.

While the embodiment of the present invention has been described with reference to the drawings, the present invention can be applied to other embodiments.

For example, in the above-described embodiment, the pulse wave deviation determining means 82 (SS6) determines the area change rate ΔS _L / S within a predetermined range on the left and right of the center line of the reference amplitude distribution curve.
_L and ΔS _R / S _R difference (ΔS _L / S _L ) − (ΔS _R
/ Based on S _R), but whether the deviation of the artery occurs has been determined, the difference of the pair of areas S _L and S _R, or based on the ratio between the area increase [Delta] S _L and [Delta] S _R The displacement of the artery may be determined.

Further, in the embodiment of FIG. 9 described above, SS2, SS4 and SS5 for calculating the average amplitude distribution curve are provided, but they are not necessarily provided.

In the above-described embodiment, the cuff 10 is attached to the upper arm and the pressure pulse wave sensor 46 is attached to the wrist to detect the pressure pulse wave of the radial artery. The pressure pulse wave sensor 46 wound around the leg may be attached to the foot to detect the pressure pulse wave of the dorsal foot artery of the leg on which the cuff 10 is not wound.

In the above-described embodiment, when the position of the pressure pulse wave sensor 46 is changed by the pressing position correcting means 84 to reduce the displacement of the radial artery 56, the estimated blood pressure becomes a predetermined value or a predetermined ratio. In the case of the above change, S6 and subsequent steps corresponding to the blood pressure value determining means 70 may be automatically executed.

Further, the blood pressure value measuring means 70 of the above-described embodiment is used.
Is configured to measure blood pressure by the so-called oscillometric method, but measures blood pressure by the so-called K sound method that determines the cuff pressure at the time of occurrence and disappearance of Korotkoff sound as the highest blood pressure value and the lowest blood pressure value. It does not matter.

In addition, the present invention can be variously modified without departing from the gist thereof.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a blood vessel tracking type continuous blood pressure monitoring device according to an embodiment of the present invention.

FIG. 2 is an enlarged view illustrating a pressure pulse wave detection probe of the embodiment of FIG. 1 with a part cut away.

FIG. 3 is a diagram illustrating a pressure pulse wave detected by the pressure pulse wave sensor of the embodiment of FIG. 1;

FIG. 4 is a diagram illustrating a correspondence relationship used in the embodiment of FIG. 1;

FIG. 5 is a functional block diagram for explaining a main part of a control function of the control device according to the embodiment of FIG. 1;

FIG. 6 is a diagram illustrating an optimum pressing force determined by an optimum pressing force control unit in FIG. 5;

FIG. 7 is a diagram for explaining the content of a displacement determination by the arterial displacement determining means of FIG. 5;

8 is a flowchart illustrating a main part of a control operation of the control device according to the embodiment of FIG. 1 and shows a main routine.

FIG. 9 is a flowchart showing an arterial misalignment correction control routine that is repeatedly executed in parallel with the main routine of FIG. 8;

[Description of sign]

 10: Cuff 42: Wrist (living body) 46: Pressure pulse wave sensor 56: Radial artery (artery) 62: Pressing device 64: Width moving device 76: Optimal pressing position control means 80: Optimal pressing force control means 82: Artery Deviation determining means 84: Pressed position correcting means

Claims (1)

[Claims] 1. A pressure pulse wave sensor having a plurality of pressure detecting elements arranged on a pressing surface in a width direction of an artery for detecting a pressure pulse wave generated from an artery of a living body, and the pressure pulse wave sensor. A pressing device that presses toward the artery, and a width direction moving device that moves the pressure pulse wave sensor in the width direction to change the pressing position where the pressure pulse wave sensor is pressed in the width direction of the artery. An optimal pressing position control means for positioning the pressure pulse wave sensor at a position immediately above the artery by the width direction moving device based on the pressure pulse wave detected by the pressure pulse wave sensor; Optimum pressing force control means for pressing the pressure pulse wave sensor by the pressing device with an optimum pressing force determined in advance so that the portion is substantially flat and maintaining the optimum pressing force; With the pressure detection element of the pulse wave sensor Estimating blood pressure value determining means for sequentially determining an estimated blood pressure value of the living body based on the magnitude of the detected pressure pulse wave, and continuously monitoring the blood pressure value of the living body based on the estimated blood pressure value In the device, in the state where the pressing force of the pressure pulse wave sensor is maintained at the optimum pressing force by the optimum pressing force control means and the estimated blood pressure value of the living body is determined by the estimated blood pressure value determining means, An arterial displacement determining means for determining a positional displacement of the artery with respect to the pressing surface of the pulse wave sensor; and The pulse wave sensor is moved to the width direction moving device so that the displacement of the artery is reduced while the pressing force of the pressure pulse wave sensor is maintained at the optimum pressing force by the pressing force control means. Vessel tracking type continuous blood pressure monitoring device, characterized in that the pressure position correcting means includes.