JP2003199719A - Hemomanometer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hemomanometer capable of continuously measuring the blood pressure. <P>SOLUTION: The highest blood pressure Po1 and the lowest blood pressure Po2 are calculated from the pressure pulse wave by a cuff 2 and a cuff pressure sensor 24, and a reference blood pressure area V0 is also calculated. Near infrared light is irradiated by a photoelectric sensor 7 and the quantity of the reflected light from a blood vessel is detected as the photoelectric volume pulse wave, and light of a wavelength shorter than blue light is irradiated by a body movement sensor 8 to detect the body movement of a subject. By subtracting the output waveform of the body movement sensor 8 from the output waveform of the photoelectric sensor 7, that is the photoelectric volume pulse wave, the body movement component is removed from the photoelectric pulse wave. After that, a data processing device 20 determines whether the cycle of the photoelectric volume pulse wave is within a permissible range or not, and the waveform data of an abnormal cycle part are replaced with a previously calculated standard waveform model. In this way, the blood pressure is calculated based on the pressure pulse wave and the photoelectric pulse wave from which the component leading to an error is removed. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a blood pressure measuring device.

[0002]

2. Description of the Related Art Conventionally known digital blood pressure measuring means is generally based on a pressure pulse wave oscillation method called an oscillometric method. This is a method of measuring blood pressure in the process of gradually depressurizing the artery after sending air to the cuff (arm girdle) to compress the artery, and the vibration of the blood vessel wall synchronized with the heart beat was built into the cuff. It is captured as the pressure fluctuation (pressure pulse wave) of the rubber bag.

[0003]

By the way, since blood pressure varies depending on the surrounding environment and internal conditions, it is desirable that continuous measurement be possible rather than intermittent measurement of several degrees.
The above-mentioned conventional digital sphygmomanometer cannot meet such a request. The present invention was completed in view of the above circumstances, and an object thereof is to provide a blood pressure measurement device capable of continuously measuring blood pressure.

[0004]

As a means for achieving the above object, the invention of claim 1 provides a cuff for compressing a blood vessel of a subject and a pressure pulse wave from a portion compressed by the cuff. A cuff pressure sensor for detecting, a photoelectric sensor for irradiating the blood vessel of the subject with light of a predetermined wavelength and continuously detecting the amount of transmitted light or reflected light by this irradiation light as a photoelectric volume pulse wave, and the pressure pulse wave. A blood pressure measuring device comprising a calculation means for continuously calculating a blood pressure value from a blood pressure calculation algorithm based on the photoelectric volume pulse wave, and a display means for displaying a transition of the blood pressure value, wherein the calculation means is the Whether or not the waveform data of the photoelectric plethysmogram is within an allowable range that can be normally taken is determined, and when a part of the waveform data is out of the allowable range, the waveform data of the photoelectric plethysmogram is allowed. range Having said waveform data part was configured to perform a replacement process of replacing the waveform data is within the allowable range taken in the past on the.

According to a second aspect of the present invention, in the first aspect, the calculating means detects the period of the photoelectric volume pulse wave as the waveform data, and the period in the photoelectric volume pulse wave is the allowable range. It is characterized in that a range that can usually be taken is set in advance and the determination is performed based on this allowable range and the period of the photoelectric volume pulse wave.

The invention of claim 3 relates to claim 1 or claim 2.
In the above-mentioned one, the arithmetic means is characterized in that the waveform data collected in the past is accumulated and a standard waveform model is calculated from the accumulated waveform data as waveform data within the allowable range.

According to a fourth aspect of the present invention, in any one of the first to third aspects, a light having a wavelength shorter than that of the photoelectric sensor is irradiated to determine the amount of reflected light on the skin surface of the subject. A feature is that it is provided with a body movement sensor that continuously detects changes, and the arithmetic means is configured to perform a correction process of subtracting the output waveform of the body movement sensor from the output waveform of the photoelectric volume pulse wave. .

According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the calculating means is a blood flow amount based on the photoelectric volume pulse and the pressure pulse wave.
It is characterized in that the cardiac output and the arterial oxygen saturation are continuously calculated.

[0009]

<Invention of Claim 1><Invention of Claim 1> According to the invention of Claim 1, in the process of depressurization after the blood vessel is compressed by the cuff, the pressure fluctuation in the blood vessel is detected by the cuff pressure sensor. It is detected as a wave (absolute value). During this period, when the photoelectric sensor irradiates the skin with light of a predetermined wavelength, blood hemoglobin has a strong absorption spectrum for light in a certain wavelength band, so the amount of transmitted light or reflected light is determined by the volume of blood vessels. It changes according to the amount of hemoglobin that changes with the change, and the state of the change over time is the photoelectric volume pulse wave (relative value)
Detected as. After that, the calculation means calculates the blood pressure value from the blood pressure calculation algorithm based on the photoelectric volume pulse wave which is the relative value and the pressure pulse wave which is the absolute value, and displays the transition thereof. In this way, if the pressure pulse wave is calculated in advance by the cuff pressure sensor for the subject, the photoelectric volume pulse wave that is continuously measured can be converted into an absolute value, and continuous re-pressurization is not performed by the cuff. Then you can measure your blood pressure.

Further, the calculating means determines whether or not the waveform data of the photoelectric volumetric pulse wave is within the allowable range, and the abnormal data portion in the photoelectric volumetric pulse wave, that is, the waveform data portion outside the allowable range ( For example, a measurement error caused by a large body movement of the subject, or a measurement error caused by a displacement of the measurement height with respect to the heart) is replaced with waveform data within the allowable range collected in the past. Therefore, it is possible to exclude abnormal data in the photoelectric volume pulse wave,
When data analysis of blood pressure values (for example, when calculating the average value of blood pressure values) is performed after data collection, highly reliable blood pressure diagnosis can be performed.

<Invention of Claim 2> According to the invention of Claim 2, the determination of the photoelectric volumetric pulse wave is made based on the period of the photoelectric volumetric pulse wave. <Invention of Claim 3> According to the invention of Claim 3, when the calculation means performs the replacement process, the waveform data portion outside the allowable range of the waveform data of the photoelectric volumetric pulse wave is replaced with the standard waveform model. To be

<Invention of Claim 4> According to the invention of Claim 4, the body motion of the subject can be detected by continuously detecting the reflected light reflected by the skin of the subject by the body motion sensor. Further, since the calculating means performs the correction process of subtracting the output waveform of the body movement sensor from the waveform of the photoelectric volume pulse wave, the error amount due to the body movement of the subject can be excluded and an accurate blood pressure value can be obtained.

<Invention of Claim 5> According to the invention of Claim 5, the arithmetic means calculates the blood flow rate, cardiac output, and arterial oxygen saturation level from a known algorithm based on the photoplethysmogram and pressure pulse wave. It can be calculated continuously.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a blood pressure measuring device 1 according to the present invention will be described with reference to FIGS. In FIG. 1, reference numeral 2 denotes, for example, a cuff that can be worn on the wrist (may be worn on the upper arm), and has a rubber bag built therein.
A tube is connected to this rubber bag and is connected to a pump 6 for supplying air. Further, an on-off valve 3 is interposed in the middle of the tube so that air can be supplied to and exhausted from the rubber bag inside the cuff 2 by the opening / closing operation. Further, a cuff pressure sensor 4 for detecting air fluctuations in the rubber bag is incorporated in the cuff 2, and is connected to a data processing device (corresponding to a computing means of the present invention) 20 described later.

A photoelectric sensor 7 and a body movement sensor 8 are provided as parts to be mounted side by side on the cuff 2 (the photoelectric sensor 7 and the body movement sensor 8 may be incorporated in the cuff 2). In this embodiment, the photoelectric sensor 7 includes a light emitting red LED (light projector) capable of irradiating the skin with light having a near infrared light wavelength (for example, 640 mm) and a phototransistor (light receiver) for receiving the reflected light. ) And. Infrared light can reach the radial artery deep in the skin, and the output of the phototransistor is detected as a relative change in blood flow due to a change in absorbance with the volume of the blood vessel.

As the body movement sensor 8, in this embodiment, a light emitting blue LED (light projector) capable of irradiating the skin with light having an external blue wavelength (for example, 420 mm) and a photo receiving the reflected light thereof. It consists of a transistor (light receiver). The blue light is reflected on the skin surface, and the output of the phototransistor is detected as a slight movement of the subject during the measurement.

FIG. 2 is a blood pressure measuring device 1 according to this embodiment.
FIG. 2 is a block diagram showing an electrical configuration of the cuff 2 described above.
The cuff pressure sensor 4 in the inside is connected to a low-pass filter 9 and a high-pass filter 10 via an amplifier 11, and a data processing device 20 in a state where predetermined frequency components are cut off respectively.
It is designed to be input to. The photoelectric sensor 7 is also connected to the low-pass filter 15 and the high-pass filter 16 via the amplifier 14, and is further input to the data processing device 20.

In the low-pass filter 15 connected to the photoelectric sensor 7, in order to remove low-frequency components that become noise, components of 30 HZ or less are cut in this embodiment,
Similarly, the high-pass filter 16 is set so as to be able to cut a predetermined high frequency component (150 HZ or more). Further, the body motion sensor 8 is an amplifier 18
It is connected to the active filter 19 (band pass filter) via the, and cuts components other than the predetermined frequency band and inputs them to the data processing device 20.

Next, the data processing device 20 will be described. A signal input from the cuff pressure sensor 4 into the data processing device 20 is connected to a CPU 21 which performs an arithmetic process via a multiplexer 22. The input signal from the photoelectric sensor 7 is connected to the multiplexer 22 and the CPU 21 via the pulse wave reproduction circuit 24 described below, and the input signal from the body motion sensor 8 is transmitted to the CPU 21 via the pulse wave reproduction circuit 24 and the multiplexer 22. It is connected to everywhere. Also, CP
A memory 23 is connected to U21, and a monitor (corresponding to the display means of the present invention) 30 for displaying the output of the arithmetic processing is connected.

The pulse wave regeneration circuit 24 includes filters 1
By subtracting the output waveform of the body movement sensor 8 from the output waveform of the photoelectric sensor 7 after passing through 4, 15, and 16, the waveform obtained by removing the body movement (particularly minute movement of the subject) from the output of the photoelectric sensor 7 is obtained. It plays a role of generating. The processing by the pulse wave reproduction circuit 24 corresponds to the correction processing of the present invention.

Next, the data processor 20 calculates the blood pressure value based on the inputs from the sensors 4, 7, and 8. The calculation process will be described with reference to the flowchart shown in FIG. First, a processing procedure for calibrating the data processing device 20 is performed during measurement (steps a to g in FIG. 3). That is, when the cuff pressure and the pressure pulse wave are input, the maximum and minimum both blood pressure values and absolute values of the pulse rate, which serve as the reference at the predetermined reference time, are measured based on the inputs (steps a and b). ). The highest and lowest blood pressure values are calculated by the known oscillometric method. Subsequently, the blood pressure area (reference blood pressure area) Ao at the reference time is calculated (step c). The reference blood pressure area Ao is determined by the area of a plane figure determined by both the highest and lowest blood pressure values Po1 and Po2 in one heartbeat cycle To with the time as the horizontal axis and the blood pressure as the vertical axis. Specifically, FIG.
As shown in, the reference blood pressure area Ao has a rectangular region (lower region area Aop2) formed by the horizontal side for one heartbeat time To and the vertical side for the minimum blood pressure Po2, and the bottom side for one heartbeat time To, high. Is the difference between the systolic blood pressure Po1 and the diastolic blood pressure Po2 (the upper area area Aop
It is calculated from the sum of 1) and.

On the other hand, when the pressure pulse wave is measured at the same time, that is, the output of the photoelectric sensor 7 measured at the reference time, that is, the photoelectric volume pulse (hereinafter referred to as photoelectric pulse wave) is input, Body movement processing is performed by the wave regeneration circuit 24 (steps d and e), and the pulse wave area (reference pulse wave area)
Vo is required (step f). Specifically, the reference pulse wave area Vo is obtained as an integrated value of changes in blood flow within one heartbeat time To as shown in FIG. Next, the reference pulse wave area Vo
The area ratio (Ao / Vo) between the reference blood pressure area Ao and the reference blood pressure area Ao is calculated. The area ratio (Ao / Vo) thus obtained becomes the calibration value, and based on this value, each sensor 7,
For 8 the light intensity is automatically adjusted,
The automatic gain adjustment is also performed on the output (step g). As a result, the level of the output of each sensor 7, 8 is automatically adjusted.

The blood pressure value is measured under the above-described gain adjustment. Even in this case, processing for removing noise components such as body movements other than the photoelectric pulse wave is performed. That is, as described above, the photoelectric sensor 7
Of the photopulse wave, that is, the low-pass and high-pass filters 15 and 16 remove the frequency components in the predetermined frequency range, and at the same time, the active filter 19 also removes the components other than the predetermined frequency from the output of the body motion sensor 8. Are removed. Then, the pulse wave regeneration circuit 24 subtracts the body movement waveform from the waveform of the photoelectric pulse wave (step h), thereby removing the measurement error amount due to the minute body movement of the subject from the photoelectric pulse wave.

Then, the blood pressure area At is calculated by multiplying the above-mentioned area ratio (Ao / Vo) by the corrected pulse wave area Vt for each heartbeat obtained from the photoelectric pulse wave that has been filtered as described above. (Step i). Subsequently, the data processing device 20 determines the photoelectric pulse wave, that is, whether the period of the photoelectric pulse wave is within the allowable range (j
Process). The allowable range is a range (for example, 0.75 to 1.5 sec) in which the period of the photoelectric plethysmogram can normally take, and when the subject has a large body movement during the measurement of the photoelectric plethysmogram, the photoelectric pulse is measured. The waveform of the wave is disturbed and its period is out of the allowable range. Then, when the period of the photoelectric pulse wave is within the allowable range, the process proceeds to the first blood pressure calculation step (step k), and when it is outside the allowable range, the step of performing the photoelectric pulse wave replacement process (step n) is performed.

First, the case where the process has proceeded to the first blood pressure value calculation step will be described, and the case where the process has proceeded to the replacement process will be described. In the first blood pressure calculation step, the blood pressure area At
Based on, the blood pressure value is continuously obtained from the blood pressure calculation algorithm. Specifically, first, in the step b, the systolic blood pressure P
o1, the diastolic blood pressure Po2, and the heartbeat time To are calculated, and from these, in the step c, the reference blood pressure area Ao and the upper region area A are calculated.
op1 and lower region area Aop2 are as follows (1) to (3)
It is calculated according to the formula. Aop1 = (Po1-Po2) / 2 * To ... (1) Aop2 = Po2 * To ... (2) Ao = Aop1 + Aop2. (3) Here, Aop1: Aop2 = K ... (4).

Next, assuming that the maximum blood pressure value in the blood pressure area At calculated in step i is Pt1, the minimum value is Pt2, and the heartbeat time is Tt, the blood pressure area At and the upper region area At are obtained.
p1 and the lower region area Atp2 can be expressed by the following equations (5) to (7). Atp1 = (Pt1-Pt2) / 2 * Tt ... (5) Atp2 = Pt2 * Tt (6) At = Atp1 + Atp2. (7) Here, the ratio of the upper region area Atp1 and the lower region area Atp2 of the blood pressure area At is such that the upper region area Aop1 and the lower region area of the reference blood pressure area Ao. Assuming that the ratio K to the area Aop2 is equal, the following expression (8) is obtained. Atp1: Atp2 = K (8) From the expressions (7) and (8), Atp1 = K / (1 + K) × At. ····································································································································· (10) Then, Pt2 = At / ((1 + K) × Tt) (11) is obtained. Further, from the equations (5), (9), and (11), Pt1 = (2K + 1) × At / ((1 + K) × Tt) (12) is calculated, and the maximum blood pressure value P per heartbeat P
t1 and the minimum value Pt2 are obtained.

Then, the data processing device 20 checks the calculated blood pressure value by collating it with the blood pressure reference value (step l). This blood pressure reference value is a range of blood pressure values obtained by normal measurement (for example, 50 to 140 mmHg), and when the calculated blood pressure value is within this blood pressure reference value, it is determined that “the measurement has been correctly performed”. Then, the transition of the blood pressure value is displayed on the monitor 30 (step m), and when the blood pressure is out of the reference value, the process returns to the step of determining the “measurement error” and calculating the systolic blood pressure / diastolic blood pressure again. Is calculated.

On the other hand, prior to the processing in the case of proceeding to the photoelectric pulse wave replacement processing step, the memory 23 accumulates the waveform data of the photoelectric pulse wave collected in the past, and the peak value and the cycle are calculated from the accumulated data. A standard waveform model of the photoelectric pulse wave is calculated by calculating the average value of the above. Then, in the replacement process step, as shown in FIG. 7, the abnormal waveform portion of the measured photoelectric pulse wave, that is, the waveform data from the beginning to the final time point of the waveform data portion outside the allowable range is converted into the standard waveform data. Along with replacement (hatched portion in FIG. 7B), the blood pressure area At of the waveform data portion outside the allowable range
Is replaced with the average value Az of the blood pressure areas of the past photoelectric pulse waves. Then, the blood pressure value is calculated in the second blood pressure value calculation step (step o). That is, for the waveform data portion within the allowable range, the blood pressure value is calculated based on the blood pressure area At as in the first blood pressure step, and for the waveform data portion outside the allowable range, the average value Az of the replaced blood pressure area is calculated. The blood pressure value is calculated based on this.
After that, the process goes to the above-mentioned step 1 to check the blood pressure value. Incidentally, the data processing device 2 is accompanied by the measurement of the blood pressure.
0 indicates that the pulse E is detected from the photoelectric pulse wave over time.

The blood pressure measuring device 1 of the present embodiment has the arterial blood oxygen saturation (blood oxygen saturation) in addition to the above-described blood pressure value calculation.
SaO2 is calculated, and the calculation procedure will be described below with reference to the flowchart of FIG.
First, as described above, the cuff pressure sensor 4, the photoelectric sensor 7, and the body motion sensor 8 detect the pressure pulse wave and the photoelectric pulse wave, and the data processing device 20 calculates the blood pressure value based on these.
Then, the pressure variation ΔP in the blood vessel is calculated from the blood pressure value by a known algorithm, and the average value D of the blood flow velocity is calculated according to the equation (1). D = 1/2 × (1 / (4 × h)) × (ΔP / ΔL) × R ² ... (13) h ... Viscosity (in this embodiment, h = 0.04) ΔL ... Tube length from heart to measurement unit (in the present embodiment,
L = 20 cm) R ... blood vessel diameter (in the present embodiment, R = 0.15 cm)

Then, according to the equations (14) to (16),
The data processing device 20 calculates the blood flow Q, the cardiac output Co, and the heart coefficient Cx. Q = π × R ² × D ... (14) Co = E × Q ... (15) Cx = Co / S (16) E ... Pulse S ... Body surface area (S = 3.4 L / in this embodiment)
min / m ² )

Further, the data processor 20 uses the known algorithm based on the photoplethysmogram to detect the arterial oxygen content CaO2.
And the mixed venous oxygen saturation content CvO2 is calculated, and the arterial oxygen saturation SaO2 is calculated according to the equation (5). SaO2 = (CaO2-CvO2) * Cx (17) Then, the change in the arterial oxygen saturation SaO2 is monitored 30.
Is displayed in.

Next, the operation and effect of this embodiment will be specifically described. A procedure for continuously measuring the blood pressure value of the subject will be described. First, the blood pressure measurement device 1 is set on the subject. Specifically, the cuff 2 is attached to the wrist part of the subject, and the power of the data processing device 20 is turned on. Then, the pump 6 is driven to supply air to the rubber bag of the cuff 2.
The air supply to the cuff 2 is continued until the pressure pulse wave is no longer detected. When the pressure pulse wave stops appearing, cuff 2
The supply of air to the chamber is stopped, the on-off valve 3 is opened, and decompression is started. As a result, the maximum and minimum blood pressures P in the CPU 21 are calculated according to the oscillometric method described above.
Measurement of o1, Po2 and pulse is performed (steps a and b).

On the other hand, the photoelectric sensor 7 and the body movement sensor 8 irradiate the skin with light having different wavelengths. Near-infrared light is emitted from the photoelectric sensor 7 to reach the deep part of the skin, and the reflected light reflected by the radial artery is received by a phototransistor which is a light receiver. The body movement sensor 8 irradiates the surface of the skin with blue light, and the reflected light is received by a phototransistor, which is a light receiver (step d). Then, each of these is subjected to the above-described filter processing. After that, the data processing device 20 obtains the reference pulse wave area Vo based on the output of the photoelectric sensor 7 (steps e and f). Next, the area ratio (Ao / Vo) is calculated from the reference pulse wave area Vo and the reference blood pressure area Ao, and the area ratio (Ao / Vo) is calculated.
/ Vo), a calibration process such as automatic gain adjustment and automatic light amount adjustment is performed, and as a result, the output level of the photoelectric sensor 7 is adjusted (step g).

Thus, following the calibration process of the blood pressure measurement device 1, the actual measurement stage is reached. The output data of the photoelectric sensor 7 is low-pass / high-pass filter 1
Only the pure pulse wave component is obtained through the noise removal processing by these through 5 and 16, and further, the body movement sensor 8 detects the minute change in the body movement of the subject and the correction processing for reducing these body movement components. It is continuously taken out (step h).
In this way, since the error component can be excluded from the waveform of the photoelectric pulse wave, an accurate photoelectric pulse wave can be obtained. Then, based on the photoelectric pulse wave subjected to the body movement processing, the data processing device 2
0 calculates the corrected pulse wave area Vt for each heartbeat, and further, the corrected pulse wave area Vt is multiplied by the above area ratio (Ao / Vo) to calculate the blood pressure area At (step i).

Further, in this embodiment, the body movement sensor 8 is
In order to exclude an error or the like due to a large body movement that cannot be detected by, the determination of the photoelectric pulse wave (step j) is performed. That is, the data processing device 20 determines whether or not the period of the photoelectric pulse wave is within the allowable range. When the period of the photoelectric pulse wave is within the allowable range, the process proceeds to the first blood pressure step and the blood pressure is calculated according to the blood pressure calculation algorithm. A value is calculated (step k), and when it is out of the allowable range, the abnormal waveform portion is replaced with standard waveform data (step n), and the blood pressure area At of the abnormal waveform portion is replaced with the average value Az of the blood pressure area. The blood pressure value is calculated in accordance with the blood pressure calculation algorithm in the 2 blood pressure step (step o). After that, after the blood pressure value is checked, the transition of the blood pressure value is displayed on the monitor 30 (steps 1 and m).

As described above, according to this embodiment, if the pressure pulse wave is calculated in advance for the subject by the cuff pressure sensor 4, the photoelectric volume pulse wave continuously measured can be made into an absolute value, Blood pressure can be continuously measured without re-pressurization by the cuff 2. Further, the pulse wave regenerating circuit removes an error component from the photoelectric pulse wave into a minute body movement, and the body movement sensor 8 is determined by the photoelectric pulse wave determination and replacement processing.
It is possible to eliminate errors due to large body movements that cannot be detected with. Therefore, when data analysis of blood pressure values (for example, when calculating the average value of blood pressure values) is performed after the blood pressure values are collected, highly reliable blood pressure diagnosis can be performed.

In this embodiment, the photoplethysmogram and the pressure pulse wave are measured with the wrist as the measurement site, but the height from the heart varies depending on the angle of the subject's arm, which may cause a measurement error. As a countermeasure against such a case, an angle sensor that can detect the angle of the subject's arm can be attached, and the data processing device 20 can perform angle compensation based on the output from this sensor. Furthermore, if the incident angle of the infrared light emitted from the photoelectric sensor 7 to the subject's arm is intentionally changed, the cross-sectional area of the blood vessel changes with respect to the incident angle of the photoelectric pulse wave. Therefore, the cross-sectional area of the blood vessel, and thus the blood vessel diameter R, can be measured from the change in the photoelectric pulse wave associated with the change in the incident angle.

<Other Embodiments> The present invention is not limited to the embodiments described above and illustrated in the drawings. For example, the following embodiments are also included in the technical scope of the present invention. In addition to the above, various modifications can be made without departing from the scope of the invention.

(1) In the present embodiment, the waveform data portion outside the allowable range of the photoelectric pulse wave waveform data is replaced with the standard waveform which is the average waveform of the past photoelectric pulse wave. If so, it is preferable to replace it with the subject's own data.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a blood pressure measurement device according to an embodiment of the present invention.

FIG. 2 is a block diagram of a blood pressure measurement device.

FIG. 3 is a flowchart showing a procedure for calculating a blood pressure value.

FIG. 4 is a waveform diagram showing a cuff pressure and a pressure pulse wave.

[Figure 5] Blood pressure area diagram

[Figure 6] Pulse wave area diagram

FIG. 7 (a) is a graph showing the transition of the photoelectric pulse wave before the replacement process, and (b) is a graph showing the transition of the photoelectric pulse wave after the replacement process.

FIG. 8 is a flowchart showing a procedure for calculating arterial oxygen saturation.

[Explanation of symbols]

1. Blood pressure measuring device 2 ... Cuff 4 ... Cuff pressure sensor 7 ... Photoelectric sensor 8 ... Body motion sensor 20 ... Data processing device (calculation means) 30 ... Monitor (display means)

Continued front page    (72) Inventor Toru Takemoto             6 Toyota Town, Toyota City, Aichi Prefecture Kyo Co., Ltd.             Yutaka Factory (72) Inventor Toshihiro Honda             6 Toyota Town, Toyota City, Aichi Prefecture Kyo Co., Ltd.             Yutaka Factory (72) Inventor Noriaki Sakakibara             93 shares, Nakamaeda, Inagaya-cho, Kariya city, Aichi prefecture             Ceremony company K & S F-term (reference) 4C017 AA08 AA11 AC01 AC26 BC11                       BD01 FF15                 4C038 KK01 KL07 KM01 KX01

Claims (5)

[Claims] 1. A cuff for compressing a blood vessel of a subject, a cuff pressure sensor for detecting a pressure pulse wave from a portion compressed by the cuff, and a light of a predetermined wavelength is radiated to the blood vessel of the subject. A photoelectric sensor that continuously detects the amount of transmitted light or reflected light as a photoelectric plethysmogram, and a calculation that continuously calculates a blood pressure value from a blood pressure calculation algorithm based on the pressure plethysmogram and the photoelectric plethysmogram. A blood pressure measuring device comprising means and display means for displaying the transition of the blood pressure value, wherein the calculating means determines whether or not the waveform data of the photoelectric volumetric pulse wave is within a generally allowable range. When a part of the waveform data is outside the allowable range, the waveform data part outside the allowable range of the waveform data of the photoelectric volumetric pulse wave is placed in the waveform data within the allowable range collected in the past. A blood pressure measurement device characterized in that it is configured to perform a replacement process. 2. The calculating means detects the period of the photoelectric volume pulse wave as the waveform data, and predetermines a range in which the period of the photoelectric volume pulse wave can be normally set as the allowable range. The blood pressure measurement device according to claim 1, wherein the determination is performed based on the period of the photoelectric volume pulse wave. 3. The calculation means stores the waveform data collected in the past and calculates a standard waveform model as waveform data within the allowable range from the accumulated waveform data. The blood pressure measurement device according to. 4. A body motion sensor for irradiating light having a wavelength shorter than that of the photoelectric sensor to continuously detect a change in the amount of reflected light on the skin surface of the subject, and the arithmetic means is the photoelectric volume pulse wave. The blood pressure measurement device according to claim 1, wherein the blood pressure measurement device is configured to perform a correction process of subtracting the output waveform of the body motion sensor from the output waveform of. 5. The calculating means is configured to continuously calculate a blood flow rate, a cardiac output, and an arterial oxygen saturation level based on the photoelectric volume pulse wave and the pressure pulse wave. The blood pressure measurement device according to any one of claims 1 to 4.