JP2664943B2 - Abnormality judgment device of pressure pulse wave detection device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure pulse wave detection device that detects a pressure pulse wave generated in an artery of a living body when pressed by the artery, and determines an abnormality in the detection of the pulse wave. The present invention relates to an abnormality determination device for performing the determination.

2. Description of the Related Art A pulse wave sensor provided with, for example, a semiconductor pressure-sensitive element is provided. A pressure pulse wave detection device of a type that detects a pressure vibration wave, that is, a pressure pulse wave generated as the artery expands and contracts in synchronization with the heartbeat by pressing the pressure pulse against the artery has been considered.

However, in such a device, when detecting a pressure pulse wave, the pressure position of the pulse wave sensor shifts due to, for example, body movement of a living body, or the pressure pulse wave is affected by a change in peripheral vascular resistance. In some cases, the accuracy of pulse wave detection performed continuously is not always sufficient.

Means for Solving the Problems In view of the above circumstances, the present invention has been made for the purpose of improving the accuracy of pulse wave detection by determining abnormalities in pressure pulse wave detection, and the gist thereof. A pressure pulse wave detection device that outputs a pressure pulse wave signal representing a pressure pulse wave generated in an artery of a living body by being pressed by an artery of a living body is a device that determines abnormality of the pressure pulse wave detection. And (a) an impedance pulse wave comprising an electrode attached to the epidermis of the living body, continuously detecting impedance at a portion where the electrode is attached, and outputting an impedance pulse signal representing the impedance. (B) comparing the pressure pulse wave signal and the impedance pulse wave signal with each other, and determining that a predetermined relationship between the pressure pulse wave signal and the impedance pulse wave signal is not established. Determining means for judging abnormalities in pulse wave detection by the pressure pulse wave detecting device.

In this manner, the pressure pulse wave signal representing the pressure pulse wave of the artery detected by the pressure pulse wave detection device and the impedance pulse wave representing the impedance pulse wave detected by the impedance pulse wave detection device When the relationship between the pressure pulse wave signal and the impedance pulse wave signal is not satisfied by the comparison between the signals and the determination means, the pulse wave detection by the pressure pulse wave detection device is abnormal. It is determined that there is. Therefore, according to the present invention, the position between the pressure pulse wave and the impedance pulse wave is determined in advance, for example, because the pressing position of the pulse wave sensor shifts due to body movement of the living body or the peripheral vascular resistance changes. When the relationship is no longer established, it is determined that the pulse wave detection is abnormal, so that the abnormal processing can be performed appropriately,
Accuracy of pulse wave detection can be obtained stably.

Examples Hereinafter, examples of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a diagram for explaining the configuration of a blood pressure monitoring device provided with a pressure pulse wave detection device employing the abnormality determination device of the present embodiment. A pressure pulse wave detection probe 10 shown in detail in FIG. 2 is fastened to a wrist of a living body by a support band 14 so as to be positioned on an artery 12 on a radial bone. The pulse wave detection probe 10
A relatively rigid rectangular container-shaped housing 16, a pulse wave sensor 18 housed in the housing 16, and a pulse wave sensor 18 interposed between the housing 16 and the pulse wave sensor 18 to connect the artery 12 It is composed of a rubber-made annular diaphragm 20 that is supported immediately above the living body in contact with the epidermis.

An electric pump 22 is provided in the housing 16 through a pipe 19.
, A pressure fluid is supplied via a pressure regulating valve 24. Pressure regulating valve 24, which pressure the pressure fluid from the electric pump 22 tone, about 40mmHg expected to be lower than a diastolic blood pressure of the living body in the housing 16 to reach the target pressure P _m to a predetermined quickly increasing state to rapidly raise the pressure P, the slow boosting state gradually increasing in the target pressure P _m from the pressure P of about 5～6MmHg / sec which is determined suitable in advance in the pulse wave detected for a predetermined speed, the housing The pressure can be switched between a pressure maintaining state in which the inside of the chamber 16 is maintained at a constant pressure and a rapid exhaust pressure state. Further, a pressure sensor 26 is connected between the housing 16 and the pressure regulating valve 24 via a pipe 19 to detect the pressure P in the housing 16 and to detect the pressure P.
Is output to the CPU 28 described later via the A / D converter 31.

The pulse wave sensor 18 includes a semiconductor strain sensor or a piezoelectric element for converting the pulsation of the artery 12 into an electric signal, and when a pressure fluid is supplied into the housing 16, the diaphragm 20 expands. Along with detecting the pressure pulse wave of the artery 12 by being pressed against the artery 12,
Band-pass filter 2 a pressure pulse wave signal SM _P representing the pressure pulse wave
5 and to the CPU 28 via the A / D converter 27.

The CPU 28 constitutes a so-called microcomputer together with the RAM 30 and the ROM 32. The CPU 28 processes an input signal according to a program stored in the ROM 32 in advance while using the storage function of the RAM 30, and executes a series of blood pressure measurement operations. That is, the CPU 28 turns ON / OFF the drive circuit 34 connected to the electric pump 22 through the output interface 36.
By controlling the start and stop of the electric pump 22 by supplying a signal and controlling the power supply to the electric pump 22 from the drive circuit 34, by supplying a command signal to the pressure regulating valve 24 via the output interface 36 , As shown in FIGS. 3 (a) and (b), respectively.
The pressure P in 16 is gradually increased at a predetermined rate after rapidly increased to the target pressure P _m, within its slow speed boosting period, the pressure pulse wave and the pressure signal representing the pressure pulse wave signal SM _P SP
Are sequentially stored in the RAM 30, and the systolic blood pressure value H and the diastolic blood pressure value L are respectively determined from the pressure P based on the change in the magnitude of the pressure pulse wave.

Further, CPU 28, from the pressure pulse wave detected in the slow speed boosting period within the housing 16, and determines the maximum pulse wave M _max having the largest amplitude, the maximum pressure pulse wave M _max is generated After the pressure _Pmax in the housing 16 at the time of the determination is obtained, and after the blood pressure values H and L are determined as described above, the pressure P in the housing 16 is maintained at _Pmax by feedback-controlling the pressure regulating valve 24. . Then, the peak value (highest value) and the lower peak value (lowest value) on the pulse wave detected by the pulse wave sensor 18 being pressed against the artery 12 by the pressure _Pmax, and the maximum and minimum blood pressure values H When the relationship between L and L is calculated, the maximum and minimum blood pressure values are continuously determined from the relationship based on the actual pulse wave and displayed on the blood pressure display 38. Blood pressure indicator
Reference numeral 38 denotes an upper end A and a lower end A on a CRT provided with a two-dimensional chart in which the horizontal axis 33 and the vertical axis 35 represent time and blood pressure (mmHg), respectively, as shown in FIG. 4 according to the display signal supplied from the CPU 28. B is configured to successively and continuously display bar graphs 37 each representing a systolic blood pressure value and a diastolic blood pressure value. The CPU 28 is supplied with a pulse signal CK of a predetermined frequency from a clock signal source 39.

A pair of electrodes 40 and 42 are fixed at predetermined two positions on the epidermis of the living body at an appropriate distance, for example, at the forearm near the elbow and near the wrist.
Connected to 3. In the proximity of these electrodes 40 and 42, electrodes 46 and
48 are fixed respectively. Therefore, the electrodes 46, 48
A constant weak current flows between the electrodes 40 and 42.
Are supplied to the operational amplifier 43 from the respective amplifiers, and the voltage at the electrode 40 is subtracted from the voltage at the electrode 42 by the operational amplifier 43, whereby the impedance generated between the electrodes 40 and 42 is detected. . Then, the differential amplifier with 43 impedance pulse-wave signal SM _I representative of the impedance between the electrodes 40 and 42 is outputted from the relative band-pass filter 50, the filtered impedance pulse wave signal at the band-pass filter 50 SM _I is A / D
It is supplied to the CPU 28 via the converter 52. Therefore, in the present embodiment, the differential amplifier 43 functions as impedance pulse wave detecting means.

In CPU 28, the detected pressure pulse wave amplitude value at the pulse wave sensor 18 - with (peak-to-peak value) and M _P, and the amplitude value M _I of the impedance pulse wave is calculated, the amplitude value M _P a difference .DELTA.M _P obtained by subtracting the amplitude value M _P ^-1 of the previous pressure pulse wave, impedance pulse wave of the immediately preceding amplitude value M _I amplitude value M _I ^-1
By comparing the difference .DELTA.M _I obtained by subtracting the, whether or not a predetermined relationship between the pressure pulse wave and the impedance pulse wave is established, in other words, normally the pressure pulse wave by the pulse wave sensor 18 It is determined whether or not is detected. If it is determined that the pressure pulse wave is not normally detected, the relationship between the pressure pulse wave and the blood pressure value is corrected, and the blood pressure value is calculated again based on the relationship. is there. this is,
The pressure pulse wave obtained when the pulse wave sensor 18 is pressed against the artery 12 is relatively easily affected by noise caused by body movement of a living body or a change in peripheral vascular resistance. Since the blood pressure value obtained from the relationship determined based on the pressure pulse wave affected by the lack of reliability, the impedance pulse wave and the pressure pulse wave that are not easily affected by noise or changes in peripheral vascular resistance are determined. This is to determine whether or not an abnormality has occurred during the detection of the pressure pulse wave by comparison. Therefore, in the present embodiment, the CPU 28, the RAM 30, and the ROM 32 for determining the abnormality of the pulse wave detection constitute a determination unit.

The operation of the blood pressure monitoring device configured as described above
This will be described below with reference to the flowchart of FIG.

First, when a power supply (not shown) is turned on, step S1 is executed, and it is determined whether or not a start / stop push button (not shown) is pressed, that is, whether or not a start / stop signal is supplied to the CPU 28. When the start / stop signal is supplied after the pulse wave detection probe 10 is mounted on the wrist of the living body, step S2 is executed next, and the count value T of the timer is reset to zero. Pulse signal
Start counting CK. Subsequently, step S3 is executed, and at the same time when the operation of the electric pump 22 is started, the pressure regulating valve 24 is switched to the rapid pressure increasing state, whereby the pressure P in the housing 16 is rapidly increased. P whether has reached the target pressure P _m is determined. If it is determined that it has not arrived, step S3 is executed again. If it is determined that it has arrived, step S5 is executed. In step S5, the pressure regulating valve
24 is switched to the slow pressure rising state, and the slow pressure rising in the housing 16 is started. In such a state, step S6 is executed to determine whether or not the pressure pulse wave has been detected.If it is determined that the pressure pulse wave has not been detected yet, the process waits until the pressure pulse wave is detected. If it is determined that the error has occurred, step S7 is executed. In step S7, the pressure pulse wave detected in step S6 and the pressure P in the housing 16 at the time when the pressure pulse wave is generated are stored in the RAM 30.

In the blood pressure measurement routine of step S8, the housing 16 is determined based on the magnitude of the pulse wave sequentially stored in the RAM 30.
The actual systolic blood pressure value H and the diastolic blood pressure value L from the internal pressure P
Are determined, and the blood pressure values H and L are stored in the RAM 30. The blood pressure determination algorithm in step S8 obtains the pressure P at the time when the amplitude of the pulse wave train obtained successively changes suddenly or the pressure P at the time when the maximum value of the difference between the amplitudes occurs, and is obtained in advance. The systolic blood pressure value H and the diastolic blood pressure value L are determined based on the relationship between the pressure P and the blood pressure value. Subsequently, step S9 is executed, and it is determined whether or not the highest and lowest blood pressure values have been determined in step S8 and the measurement has been completed. Initially, the pulse wave number required for blood pressure measurement has not been obtained, so steps S6 and subsequent steps are executed again. However, if it is determined in step S9 that the measurement of the blood pressure value has been completed, the next step S10 is executed. Step S10
In, with the maximum pulse wave M _max having the largest amplitude from the pressure pulse wave detected in said slow speed boosting period within the housing 16 is determined, the maximum pulse wave M _max
The pressure _Pmax in the housing 16 at the time of occurrence of is generated is determined. In the next step S11, the pressure regulating valve 24 is switched to the pressure maintaining state by performing the field-back control after the rapid release state of the pressure so that the pressure P in the housing 16 becomes the pressure _Pmax determined in the step S10. Can be

Subsequently, in step S12, the pulse wave sensor 18 is kept in a state where the inside of the housing 16 is maintained at _Pmax as described above.
With pressure pulse wave M _P1 detected is read from the maximum value M _P1 ^max and minimum value M _P1 ^min of the pressure pulse wave M _P1 is stored in and RAM30 are determined respectively, their highest value M
Relational expression for calculating systolic blood pressure value SYS and diastolic blood pressure value DIA based on _P1 ^max and minimum value M _P1 ^min , respectively: SYS = K · M _P1 ^max + a (1) DIA = K · M _P1 ^min + A The constants K and a in (2) are determined. That is, the constants K and a are calculated by substituting the actual blood pressure values H and L determined in step S8 into the systolic blood pressure values SYS and DIA. Here, equations (1) and (2) are proportional to the maximum and minimum blood pressure values determined based on the change in the magnitude of the pressure pulse wave and the maximum and minimum values of the pressure pulse wave, respectively. It is established based on the relationship. Therefore, the constants K and a represent the slope and the intercept of the Y axis, respectively, when the blood pressure value is on the Y axis and the magnitude of the pressure pulse wave is on the X axis. Since the blood pressure value is not always zero even when the magnitude of the pressure pulse wave is zero, the relationship between the blood pressure value and the pressure pulse wave is accurate by adding the Y-intercept a. Become.

Next, in step S13, it is determined whether the pressure pulse wave subsequent to pulse wave M _P1 is detected, it is determined to have been detected, are the following step S14 is executed, the detection The read pressure pulse wave _MP2 is read and the pulse wave _MP2
The maximum value M _P2 ^max and the minimum value M _P2 ^min of
Stored in 0. In step S15, since K and a have already been determined in step S12, the maximum value M _P2 ^max and the minimum value M _P2 ^min are substituted into the above equations (1) and (2), respectively. , The systolic blood pressure value SYS and the diastolic blood pressure value DIA are determined.

In the following step S16, it is determined whether or not an abnormal signal indicating that an abnormality has occurred at the time of detecting the pressure pulse wave has occurred in an interrupt routine described later. If it is determined that an abnormal signal has occurred, steps S2 and subsequent steps are executed again.If it is determined that no abnormal signal has occurred, step S17 is performed.
Is executed, and the systolic blood pressure value SYS and the diastolic blood pressure value DIA determined in step S15 are displayed on the blood pressure display 38. In step S18, it is determined whether or not the start / stop push button has been operated again. If it is determined that the operation has been performed again, the process returns to step S1, but if it is determined that the operation has not been performed again, step S19 is executed, and the content T of the timer is set to the predetermined content T. ₀
Is determined. The counting contents T ₀ in order to correct the relationship determined in step S12, which corresponds to the time interval again determined anew K and a, for example, is set to about 5 to 10 minutes. Therefore, when the count T reaches T ₀ , the steps S2 and subsequent steps are executed again.However, at this stage, the count T has not yet reached T ₀ , and the steps S13 and subsequent steps are executed. a series of pulse wave M _P2, M _P4 following the M _P2, systolic blood pressure value SYS and the diastolic blood pressure value DIA is determined each time ... is detected.

In the process in which the main routine as described above is repeatedly executed, the interrupt routine shown in FIG. 6 is sequentially executed at predetermined relatively short fixed periods. In step SS1, it is determined whether or not an impedance pulse wave has been detected.If it is determined that the impedance pulse wave has not been detected, the operation returns to the main routine, but it is determined that the impedance pulse wave has been detected. And the following step SS2 is executed, and the detected impedance pulse wave M
The sub-value of _I1 is obtained. Next, in step SS3, .DELTA.M _I is calculated which is the difference obtained by subtracting the vibration than one sub-value of the immediately preceding impedance pulse wave M _I2 from the current detected Fufuku value of the impedance pulse wave M _I1. In step SS4, the amplitude value of the pressure pulse wave M _P2 from the maximum value M _P2 ^max and minimum value M _P2 ^min of the stored pulse wave M _P2 in step S14 is determined, the pressure pulse wave M _P2 Pressure pulse wave M just before
_From the maximum value M _P1 ^max and minimum value M _P1 ^{min of} _P1 , the pressure pulse wave M
Amplitude of _P1 is determined, .DELTA.M _P is calculated which is the difference obtained by subtracting the amplitude value of the pressure pulse wave M _P1 immediately before the amplitude of the pressure pulse wave M _P2. Then, by executing the pulse wave detection abnormality determination routine in step SS5, it is determined whether or not the pressure pulse wave is normally detected by the pulse wave sensor 18.

That is, in the pulse wave detection abnormality determination routine, first, as shown in FIG. 7, step SR1 is executed, and the amplitude value difference ΔM _P of the pressure pulse wave calculated in step SS4 is obtained.
Is determined to be within a predetermined allowable range. When it is determined that ΔM _P is smaller than the predetermined small predetermined value α and larger than the predetermined value −α, in other words, the amplitude value of the pressure pulse wave M _P2 becomes the amplitude of the immediately preceding pressure pulse wave M _P1 . If it is determined that there is almost no change from the value, step SR2
Is executed, and if it is determined that ΔM _P exceeds the predetermined value α, step SR3 is executed.If it is determined that ΔM _P is lower than the predetermined value −α, step SR4 is performed. Be executed. They step SR2, step SR3, and in step SR4, the amplitude value difference .DELTA.M _I of impedance pulse wave calculated in step SS3 is greater than or smaller predetermined value -β than the predetermined value beta, predetermined was either exceeds a slight predetermined value beta, or a predetermined value is either the determined below-beta, whether the direction of change of .DELTA.M _I coincides with the direction of change of .DELTA.M _P are determined, respectively. That is, when the .DELTA.M _I is determined to be between the predetermined value β and -β in step SR2, in a state in which the amplitude of the amplitude values of the pressure pulse wave and the impedance pulse wave is not together almost unchanged because, it is determined not affected by such detection upon noise mixing or peripheral vascular resistance changes in the pressure pulse wave, but the pulse wave detection abnormality determination routine ends, .DELTA.M _I is greater than the predetermined value β Alternatively, if the value is smaller than the predetermined value −β, it is determined that there has been an influence such as a displacement of the pressing position of the pulse wave sensor 18 or a peripheral vascular resistance in detecting the pressure pulse wave, and an abnormal signal is generated in step SR5. Is output. Further, when the .DELTA.M _I is determined and the amplitude value of the amplitude and impedance pulse wave pressure pulse wave is greater than the predetermined value β is changed both in the positive direction in step SR3, the pressure pulse wave is If it is determined that the detection is normal, but the amplitude value hardly changes or changes in the negative direction, it is determined that the pressure pulse wave detection is abnormal and an abnormal signal is output in step SR6. You. Step S
In R4, when .DELTA.M _I is determined and the amplitude of the amplitude values of the pressure pulse wave is below the predetermined value -β and impedance pulse wave has changed both in the negative direction, the pressure pulse wave is normal However, when the amplitude value hardly changes or changes in the positive direction, it is determined that the pressure pulse wave detection is abnormal, and an abnormal signal is output in step SR7. It is.

When the pulse wave detection abnormality determination routine of step SS5 is executed as described above, the interrupt routine of FIG. 6 ends, and the operation returns to the main routine of FIG. Then, in the process in which step S13 and subsequent steps of the main routine are repeatedly executed, if it is determined in step S16 that an abnormal signal has been output in the pulse wave detection abnormality determination routine of the interrupt routine, step S2 and subsequent steps are executed again. The correspondence between the pressure pulse wave and the blood pressure value is corrected in step S12 based on the newly detected pressure pulse wave. Further, in the process of step S13 following is repeatedly executed, perform together with the determination in step S16 is negative, the count contents of the timer in step S19 it is determined that T reaches T _0, step S2 follows again As a result, the actual systolic blood pressure value H newly determined in step S8
And L and the maximum value and the minimum value of the pressure pulse wave read in step S12, the correspondence equation (1)
The constants K and a in (2) are obtained, and the blood pressure value is determined based on the new correspondence.

As described above, in the above determination device of the present embodiment,
Compare the amplitude value of the impedance pulse wave, which is not easily affected by noise or peripheral vascular resistance, with the amplitude value of the pressure pulse wave, which is relatively susceptible to those effects. It is determined that the pressure pulse wave is normally detected without being affected by noise or peripheral vascular resistance, but if the pressure pulse wave is affected by a shift in the pressing position of the pulse wave sensor when detecting the pressure pulse wave, Since the change directions do not match, it is determined that the detection of the pressure pulse wave is abnormal. Therefore, by using the abnormality determination device of the present embodiment,
Since an appropriate measure can be taken when the pulse wave detection is abnormal, the accuracy of the pulse wave detection of the pressure pulse wave detection device is stabilized. As a result, when such a pressure pulse wave detection device is employed in a blood vessel monitoring device, the correspondence between the blood pressure value and the pressure pulse wave is corrected according to the determination of the pulse wave detection abnormality, so that the result of the blood pressure measurement is highly reliable. There is an effect that the property can be obtained.

As mentioned above, although one Example of this invention was described based on drawing, this invention can be suitably implemented also in another aspect.

In the above-described embodiment, when the change direction of the amplitude value of the pressure pulse wave and the change direction of the amplitude value of the impedance pulse wave do not match in the pulse wave detection abnormality determination routine shown in FIG. Although it was determined that the wave detection was abnormal, for example,
After the step SS1 in the interrupt routine shown in FIG. 6, a step for judging abnormality of the impedance pulse wave may be provided. That is, a value γ that is significantly larger than the predetermined value β that is a very small value, and a value −γ that is significantly smaller than the predetermined value −β are set, and the amplitude value of the impedance pulse wave is smaller than the predetermined value γ. If the pulse wave is larger than the predetermined value -γ, the impedance pulse wave is determined to be normal.
It is determined that one or both of the electrodes 40 and 42 are out of the living body and noise is mixed in.If the noise is smaller than the predetermined value -γ, one or both of the electrodes 46 and 48 are out of the living body and an impedance pulse wave is detected. It is determined that it has disappeared, and abnormalities of the impedance pulse wave are detected,
The operation is returned to step SS1 of the interrupt routine, and the detection of the impedance pulse wave is performed again. In this case, if it is determined that the impedance pulse wave is abnormal, an alarm device connected to the CPU 28 may generate an alarm sound or the like.

In the above-described embodiment, when it is determined that the pressure pulse wave is abnormal, the pressure pulse wave is detected again to determine the blood pressure value, and the pressure pulse wave and the blood pressure value are determined based on the blood pressure value. The relationship was corrected, but instead of or in addition to this, an alarm indicating an abnormality was displayed from an alarm device, etc., and noise removal processing was performed on the detected pressure pulse wave. Or you may.

Further, in the above-described embodiment, the pressure pulse wave is collected from the artery 12 which is a radial artery located on the radial bone near the wrist of the living body, but is located relatively close to the epidermis of the biological body. The pulse wave may be collected from another artery from which the pulse wave can be easily collected, for example, the carotid artery, the dorsal artery, and the like.

Further, in the embodiment described above, the actual blood pressure based on the change in size of the resulting pressure pulse wave by gradually increasing at a predetermined speed the pressure of the pulse wave sensor 18 from the target pressure P _m of about 40mmHg Instead of measuring the values H and L, a part of the living body which is not on the upstream side of the artery 12 pressed by the pulse wave sensor 18, for example, the arm on the side opposite to the side on which the pulse wave sensor 18 is mounted The actual blood pressure value is determined based on the pulse wave obtained by winding the cuff around the upper arm and changing the compression pressure in the cuff, and the pulse is determined based on the correspondence obtained from the actual blood pressure value. The blood pressure value may be determined using the pressure pulse wave detected from the wave sensor 18.

Further, the electrodes 40, 42, 46, and 48 may be mounted on the arm on the side opposite to the pulse wave detection probe 10.

Further, in the above-described embodiment, the abnormality determination device is used in the pressure pulse wave detection device employed in the blood pressure monitor device, but the pressure pulse wave detection device only detects the pressure pulse wave and displays the waveform thereof. May be used, and may be employed in other devices utilizing pressure pulse waves.

The above is merely an example of the present invention, and the present invention can be variously modified without departing from the spirit thereof.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a blood pressure monitoring device employing a pressure pulse wave detecting device provided with an abnormality determining device according to an embodiment of the present invention. FIG. 2 is a front sectional view showing the configuration of the pulse wave sensor of FIG. 1 in detail. FIG. 3 (a) and (b)
3 is a time chart showing a change in pressure inside the housing of FIG. 1 and a change in the magnitude of a pressure pulse wave detected by a pulse wave sensor with time, respectively. FIG. 4 is a diagram showing an example of a trend of the blood pressure value displayed on the blood pressure display in FIG. FIG. 5 is a flowchart for explaining the operation of the apparatus shown in FIG. FIG. 6 is a flowchart showing an interrupt routine periodically executed in the operation of FIG. FIG. 7 is a flowchart for explaining the operation of the pulse wave detection abnormality determination routine of FIG. 12: artery, 18: pulse wave sensor 28: CPU, 30: RAM 32: ROM, 40, 42: electrode 43: operational amplifier (impedance pulse wave detection means)

Claims (1)

(57) [Claims] A pressure pulse wave detecting apparatus for detecting a pressure pulse wave generated in an artery of a living body by being pressed by the artery of the living body and outputting a pressure pulse wave signal representing the pressure pulse wave. An apparatus for determining an abnormality in detection, comprising: an electrode attached to the epidermis of the living body, continuously detecting the impedance at a portion where the electrode is attached,
Impedance pulse wave detecting means for outputting an impedance pulse wave signal representing the impedance, and comparing the pressure pulse wave signal and the impedance pulse wave signal,
Determining means for determining an abnormality in pulse wave detection by the pressure pulse wave detection device when a predetermined relationship between the pressure pulse wave signal and the impedance pulse wave signal is not satisfied; Abnormality judging device of pressure pulse wave detecting device.