JPH1057325A - Hemomanometer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a non-invasive type hemomanometer to continuously measure blood pressure on the upper arm. SOLUTION: The hemomanometer is composed of a cuff 10 to be applied on specific part of a patient to press up the artery by pumping in the air, a sensor 12 put opposite to the cuff 10 to detect pulse displacement of the artery and a digital data processor 14 to determine highest and lowest blood pressure of the patient based on pulse signals sent from the sensor 12. The digital data processor 14 is equipped with an operation means to calculate elastic parameter to give a relation with the pulse displacement and the highest and lowest blood pressure using previously gained those values, a cuff pressure control means to keep the cuff pressure lower than previously gained lowest blood pressure, a conversion means to convert a volume pulse detected under kept-cuff pressure to an artery pressure waveform on multiplying it the elastic parameter and a display 38 to display converted artery pressure waveform in order.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-invasive sphygmomanometer capable of measuring continuous blood pressure at an upper arm.

[0002]

2. Description of the Related Art As a method of judging invasive blood pressure, there is a method of measuring a local pressure of a blood flow in a blood vessel by capturing a local part of an artery of a subject, as represented by an intra-arterial catheter method. This method has the advantages of high measurement accuracy and continuous measurement because the arterial pressure is directly measured, and is an ideal blood pressure measurement method.

On the other hand, in a non-invasive blood pressure judging method, a Livaloch blood pressure monitor detects a pulsation change in a cuff wound around an upper arm of a subject, and uses an oscillometric method for judging blood pressure. Oscillation (pulsation) also appeared at cuff pressures higher than hypertension, and judgment of diastolic blood pressure tended to be unclear.

[0004] In the Korotkoff method for detecting blood flow, the determination of blood pressure may be extremely inaccurate or impossible for a person with a weak pulse or a patient at the time of shock.

[0005] This is because, for example, the oscillometric method detects the average pulsation of the artery in the cuff;
In addition, the pulsation is such that the arterial wall displacement of the brachial artery caused by the heartbeat is propagated as a displacement of the skin surface, and the displacement of the skin surface changes the air volume in the cuff. This is because the change is detected as a pressure change, and as a result, the displacement amount of the artery wall is converted into a pressure change in the cuff.

That is, since the displacement of the arterial wall is measured using the air in the cuff as a medium, the displacement of the artery wall is affected by the extracorporeal effects of the air, such as the compression characteristics and damping characteristics, and depending on the pulse pressure waveform obtained from the cuff. This is because the arterial wall displacement cannot be accurately grasped.

[0007] By the way, cold load test, exercise load test,
In circulatory function tests such as the Valsalva test, the standing test, and blood pressure measurement during mental stress, among the blood pressures, rapid changes are observed in accordance with changes in the external environment. It is desirable to record.

However, there is a technical problem as described below when trying to perform such a measurement with a conventional sphygmomanometer.

[0009]

That is, in the Livalotch sphygmomanometer, it takes 30 to 60 seconds for each blood pressure measurement, so that continuous blood pressure measurement is not performed.
In addition, non-invasive sphygmomanometers generally have lower measurement accuracy than invasive sphygmomanometers, and although there are examples of continuous measurement of peripheral blood vessels such as fingers and wrists, continuous measurement with the upper arm is not possible And it was.

The present invention has been made in view of such a conventional problem, and its object is to measure the maximum and minimum blood pressures in advance and then use a non-invasive continuous blood pressure in the upper arm. It is an object of the present invention to provide a sphygmomanometer capable of measuring the blood pressure.

[0011]

In order to achieve the above object, the present invention provides a cuff which is attached to a main part of a subject, injects air to compress an artery, and is installed opposite to the cuff;
A sensor for detecting a volume pulsation displacement of the artery, and a pulse wave signal transmitted by the sensor,
A digital data processing unit for determining a diastolic blood pressure, wherein the digital data processing unit is configured to provide a correlation between the maximum and minimum blood pressures obtained in advance and the volume pulsation displacement. Calculating means for calculating the elasticity parameter, cuff pressure setting means for holding the cuff pressure at a pressure lower than the previously obtained diastolic blood pressure, and applying the elasticity parameter to the volume pulse wave detected under the held cuff pressure. There are provided conversion means for multiplying and converting the arterial pressure waveform, and display means for sequentially displaying the converted arterial pressure waveform. By the way, the present inventors have previously described Japanese Patent Application Nos. Hei 7-83589 and Hei 7
As proposed in Japanese Patent No. -83590, a sphygmomanometer in which an optical distance sensor for detecting pulsation displacement of an artery is provided in a cuff has been developed. According to this sphygmomanometer, since the local amount of displacement of the arterial wall can be directly measured, the above-mentioned essential drawback of the Leveroch type sphygmomanometer is corrected, and the highest and lowest blood pressures can be obtained with high accuracy. In addition to the above effects, the displacement of the skin surface corresponding to the pulsation of the brachial artery picked up by this optical distance sensor corresponds to the displacement of the blood vessel wall of the artery, and the cuff pressure is reduced to a pressure lower than the diastolic blood pressure. When setting and measuring blood pressure, it was found that a similar waveform shown in FIG. 7B can be obtained with respect to the arterial pressure waveform continuously measured by the catheter method shown in FIG. Is a plethysmographic waveform. The arterial pressure waveform is
It is a pressure fluctuation waveform in a blood vessel by the pump function of the heart.
On the other hand, a volume pulse waveform can be defined as a volume change due to a change in arterial pressure, that is, a waveform that changes in accordance with a displacement of a blood vessel wall. This is because the sensor directly picks up the output change according to the distance caused by the pulsation. However, the amplitude of the plethysmogram gradually narrows due to the effect of the cuff pressure on the inhibition of the venous regurgitation of the subject, but it is also true that the pulsation is maintained for several minutes with little effect. Therefore, the present inventors have proposed that, at a cuff pressure equal to or lower than the diastolic blood pressure, if a certain parameter can be added to the obtained plethysmographic waveform to convert it into an arterial pressure waveform, even if it is a non-invasive sphygmomanometer, an invasive sphygmomanometer Focusing on the fact that blood pressure can be continuously measured in the same manner as in, a series of conversion equations described below were considered. First,
Assuming that the blood pressure P, the blood vessel inner diameter R, the blood vessel thickness t, and the blood vessel elasticity are E, the following Lapias equation is obtained from the balance between the force for expanding the blood vessel by the internal pressure P and the tension. 2RwP = 2Tw, where w: blood vessel length, T: tension RP = T If the inner diameter when no blood vessel is loaded is R0, the blood vessel tension T can be expressed by the following equation. T = Et · (R−R0) / R0 Therefore, R / R0 = 1 / {1− (PR0 / Et)} (1) Here, the pressure P = 100 mmHg = 1.33 ×
Assuming 10 ⁵ (dyn / cm ² ), the following measured values can be given to the vascular elasticity E of the brachial artery, the vascular thickness t, and the vascular inner diameter R 0 when no load is applied. E ≒ 5 × 10 ⁵ (dyn / cm ² ), t ≒ 1 mm, R0 ≒ 2 m
m Although the actual measurement values described above slightly vary depending on the subject, most of the measured values fall within this range. Therefore, PRo / Et << 1 holds, and when this is substituted into equation (1), R / R0〓1 + (PR0 / Et) 1 / R0 · dR / dP = R0 / Et. The relationship of the arterial pressure P can be expressed. Next, at the time of measurement, the cuff pressure Pc is set to PC <Pdia with respect to the previously obtained diastolic blood pressure Pdia, and the blood vessel diameters Ra and R corresponding to the arterial pressures Pa, Psys (systolic blood pressure) and Pdia (diastolic blood pressure).
Assuming sys and Rdia, 1 / R0 · dR = ■ R0 dP / Et (however, the integration range is left side = R0 → Ra, right side = PC → Pa) Therefore, 1 / R0 · (Ra−R0) = R0 / Et · (Pa−PC) Equation (2) In the above equation, the blood vessel diameter R and the arterial pressure Pa have a linear relationship. That is, by tracing the blood vessel diameter R, it becomes possible to trace the arterial pressure Pa. This means that if the blood pressure for calibration is first measured and the highest and lowest blood pressures (Psys, Pdia) are obtained, the equation (2)
It will be able to determine the elastic parameters ^{(Et / R0 2 = K)} . That is, in equation (2), Pa = Psys, Pa
= Taking the difference between the time of Pdia, (Rsys-Rdia) = K -1 (Psys-Pdia) | Pc where k = Et / R0 ² Therefore, k = (Psys-Pdia) / (Rsys-Rdia) ·· Equation (3) is obtained. After that, the Pdia
In this state, the arterial pressure wave can be continuously monitored by picking up the volume pulse waveform and multiplying the volume pulse waveform by the elasticity parameter k while keeping the value lower than. therefore,
Volume wave pulses measured with the cuff pressure kept lower than the diastolic blood pressure are displayed continuously after being corrected to the arterial pressure waveform. Or 3 for regular venous return
By providing a cuff pressure-free period of about 0 seconds, continuous measurement can be performed in a non-invasive manner. Further, the sensor according to the present invention is an optical distance sensor that is installed opposite to the cuff and detects a pulsating displacement of the artery. Based on a photoelectric volume pulse wave signal transmitted from the optical distance sensor, the maximum and minimum of the subject are determined. And the continuous blood pressure can be determined. By adopting this configuration, since the local amount of displacement of the arterial wall can be directly measured, the above-described essential drawback of the Leveroch type sphygmomanometer is corrected, and the maximum, minimum, and continuous blood pressure can be determined with high accuracy.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. 1 to 6 show one embodiment of a sphygmomanometer according to the present invention. 1 shows the overall configuration, FIG. 2 shows a development view and a sectional view of the cuff, FIG. 3 shows a flowchart in the first half of the processing procedure, and FIG. 4 shows a flowchart in the second half of the processing procedure. 5 shows a waveform diagram for determining the highest and lowest blood pressure in the first half of the processing procedure, and FIG.
FIG. 9 shows a waveform diagram of continuous blood pressure displayed in the latter half of the processing procedure.

As shown in FIG. 1, the blood pressure monitor of the present embodiment
It is roughly composed of a cuff 10, an optical distance sensor 12, and a digital data processing unit 14. The cuff 10 is attached to a main part of the subject, specifically, the upper arm 16, and the details thereof are shown in FIG.

A cuff 10 shown in FIG. 1 is a hard curved plate 10a which is formed by bending a thin synthetic resin in an arc shape and which can be bent and deformed.
And an outer cloth 10b surrounding the outer periphery of the curved plate 10a.
And an inner cloth 10c sewn to the outer cloth 10b so as to surround the inner circumference of the curved plate 10a, an air bag 10d provided on the inner surface side of the inner cloth 10c, and sewing on the outer circumference of the outer cloth 10b. And an engaging fastener 10e for engaging the end of the inner cloth 10c.

The air bag 10d is made up of a sealed transparent synthetic resin sheet bag 10g in which reinforcing fibers 10f are incorporated in a lattice shape, as shown in a partially broken view of the developed view of FIG. ing. When the bag 10g is pressurized and the pulsation is prevented from expanding, the reinforcing fiber 10f is integrally incorporated into the bag 10g. In proportion, 10 g of the bag body can be inflated.

[0016] To this end, inside the bag 10g,
As shown in FIG. 1, a pipe 18 for air injection is connected and connected. A pressure sensor 20 and an electromagnetic control valve 22 are connected to an outer end of the pipe 18. A pump 24 that sends out air is connected to the electromagnetic control valve 22, and the electromagnetic control valve 22 and the pump 24 are controlled by a pump control unit 26.

The detection signal of the pressure sensor 20 is input to the digital data processing unit 14 via the band pass filter 28 and the A / D converter 30. The pump controller 26 includes:
A control signal is sent from the digital data processing unit 14 based on the detection signal of the pressure sensor 20.

The optical distance sensor 12 includes a photocoupler 12a fixed to the outer surface of the outer portion of the bag 10g, and a reflecting plate 12b fixed to the outer surface of the inner portion of the bag 10g so as to face the photocoupler 12a. It is composed of

The photocoupler 12a is an integrated combination of a light emitting diode and a phototransistor. The photocoupler 12a is set so that light emitted from the light emitting diode is reflected by the reflector 12b and enters the phototransistor. The magnitude of the output of the phototransistor differs depending on the distance between the photocoupler 12a and the reflector 12b.
An output signal corresponding to the displacement of the artery is transmitted.

The light emitting diode of the photocoupler 12a is turned on and off by a light emission control unit 32 connected to the digital data processing unit 14. Also, the reflection plate 12b
The light reflected by the photo-transistor is converted into an electric signal by a phototransistor.
, And are digitized via the A / D converter 36 and input to the digital data processing unit 14.

In this embodiment, since the bag body 10g is formed of a transparent synthetic resin sheet, the photocoupler 12a and the reflection plate 12b are arranged on the outer surface side of the bag body, but the opaque synthetic resin sheet is used. When the bag 10g is formed, the photocoupler 12a and the reflector 12b
May be arranged to face each other.

In the sphygmomanometer of the present invention, the optical distance sensor 12 can employ not only the combination of the photocoupler 12a and the reflector 12b but also the combination of a light emitting diode and a phototransistor. What is necessary is just to install so that these may oppose the inner and outer surface of the bag body 10g.

The digital data processing unit 14 comprises a so-called microcomputer, includes a CPU, a memory, and the like. The digital data processing unit 14 sends a control signal to the pump control unit 26 and the light emission control unit 32 based on a built-in program. Delivery and pressure sensor 20 and photocoupler 12
In response to the signal from a, the respective parts are controlled, the highest and lowest blood pressures are determined, and the continuous blood pressure is measured. The results are sequentially displayed or printed out on the display unit 38 and an external device such as a keyboard for setting. It has an input device.

The digital data processing unit 14
First, in the first half of the process, a processing operation for obtaining the maximum and minimum blood pressures of the Leveroch type for obtaining calibration data for continuous blood pressure measurement is performed, and then, in the second half, a continuous measurement operation is performed based on the calibration data.

FIG. 3 shows an example of a processing procedure in the first half of the blood pressure measurement for obtaining the calibration data executed by the digital data processing unit 14.

When measuring blood pressure, first, the cuff 10 is attached to the upper arm 16 of the subject. At this time, upper arm 1
6 is set so that the reflector 12b is located on the artery,
The cloths 10b and 10c are hung and fixed to the locking fastener 10e.

In this case, in order to ensure that the reflector 12b is positioned on the artery of the upper arm 16 of the subject, for example, as shown by phantom lines in FIG. It is desirable that the reflector 12b of any one of the sensors 12 be located on the artery. When a plurality of sensors 12 are used, the output value of each sensor 12 may be compared and the one that outputs the largest output signal may be selected.

When the mounting of the cuff 10 is completed, the preparation for the blood pressure measurement is completed. Therefore, the control procedure of the digital data processing unit 14 is started, and first, initial setting is performed in step s1. The initial settings include the upper limit of the pressure applied to the cuff 10 and the limit of the measurement time. When the initialization is completed, the calibration of the pressure sensor 20 is performed in step s2, and the electromagnetic control unit 22 is determined in step s3.
And the electromagnetic control valve 22 is opened.

In the next step s4, the electromagnetic control valve 22 is controlled based on the detection signal of the pressure sensor 20, and the cuff 10 is controlled.
Is performed at a constant speed to increase the pressure in the air bag 10d at a constant speed.

At this time, in the cuff 10 of the present embodiment, the reinforcing fibers 10f are incorporated in a lattice shape in the bag 10g of the air bag 10d, and a hard curved plate 10a is interposed on the outer peripheral side of the bag 10d. Therefore, the expansion and contraction of the bag body 10d itself is regulated by the reinforcing fibers 10f, and the outward expansion of the bag body 10d is regulated by the curved plate 10a, so that the displacement of the optical distance sensor 12 is prevented. It is possible to compress the artery while keeping the outer position of the body 10d constant.

In the following step s5, the flag i indicating the number of arterial waves is set to 0, the blood pressure determination flag Fp is also set to 0, and the output signal of the optical distance sensor 12 is fetched. In step s6, it is determined whether or not the photoelectric volume pulse signal has been detected.

The photoplethysmogram signal determined here is a signal as shown in FIG. 4 and corresponds to the inflation of the air bag 10d under constant-speed pressurization based on the output signal of the optical distance sensor 12. The part is removed, and the part corresponding to one pulsation is individually extracted and stored in the memory.

When it is determined in step s6 that the photoelectric volume pulse signal is not detected, the process proceeds to step s7,
If it is determined in step s7 that the flag i is not larger than 1, the process returns to step s6. In this case, if it is determined that the volume pulse wave is not detected in step s6 for the first time, the flag i is set to 0 in step s5, so that the process always returns to step s6.

If it is determined in step s6 that the photoplethysmogram signal has been detected, it is determined in step s8 whether or not the detected photoplethysmogram signal for one beat has a flat portion. If there is no copy, return to step s6,
A similar procedure is repeated. On the other hand, when it is determined that the photoelectric volume pulse wave signal has a flat portion, 1 is added to the flag i in step s9, and this is set as a new flag i.
Move to step s10.

In step s10, it is determined whether or not the flag i is 1. If it is 1, the determination of the diastolic blood pressure is executed in step s11. Then, if it is determined in step s10 that the flag i is not 1,
When the determination of the diastolic blood pressure ends in step 11, both steps s
Return to 6.

The process up to the determination of the diastolic blood pressure will be described more specifically. Now, for example, assuming that the photoplethysmogram signals P1, P2, P3... Pn for each beat are extracted in the state shown in FIG. 5, in step s8, the individual photoelectric signals detected in step s6 are extracted. The volume pulse wave signal P1,
It is determined whether or not P2, P3... Pn has a flat portion s.

If the pressure in the air bag 10d is smaller than the diastolic blood pressure of the subject during the process of pressurizing the pressure in the air bag 10d at a constant speed, the photoelectric plethysmogram signal is output from the air bag 10d. Pulsating without being affected by the pressure (photoelectric volume pulse wave signals P1 to P6 in FIG. 5).

However, when the pressure in the air bladder 10d becomes higher than the diastolic blood pressure of the subject, the pressure in the artery is reduced.
When the pressure is smaller than 0d, a flat portion s having no pressure change is generated in the photoelectric volume pulse wave signal. Therefore, in this embodiment, in steps s8 to s10, the photoplethysmogram signal P8 in which the flat portion s has first occurred is detected, and when the photoplethysmogram signal P7 is detected, the diastolic blood pressure is determined. ing.

In the determination of the diastolic blood pressure in step s11, for example, the pressure in the air bladder 10d at the time when the photoelectric volume pulse wave signal P7 in which the flat portion s first appears is set as the diastolic blood pressure value. The photoplethysmogram signal P6 immediately before the photoplethysmogram signal P7 in which the flat portion s appears
The pressure in the air bladder 10d at the time when the pressure is extracted is defined as the diastolic blood pressure value, and further, the average value of the pressure in the air bladder 10d at the time when the photoelectric volume pulse wave signal P7 and the photoelectric volume pulse wave signal P6 are extracted Can be the diastolic blood pressure value.

In the determination of the diastolic blood pressure in this case, as shown in FIG. 5, when the pressure in the air bladder 10d becomes larger than the diastolic blood pressure of the subject, the photoelectric volume pulse wave signal corresponds to the Korotkoff sound. Since the high-speed displacement portion K appears, the photoelectric volume pulse signal in which the high-speed displacement portion K first appears can be detected in step s8, and the diastolic blood pressure value can be obtained by the method described above in step s11. Also,
By detecting both the flat portion s and the high-speed displacement portion K, similarly,
A diastolic blood pressure value can also be determined.

As described above, after the determination of the diastolic blood pressure is performed and the value is specified, even if there is a flat portion s in the photoelectric volume pulse wave signal, the flag i is determined in step s10.
Is not determined to be 1 and therefore, from step s6 to s
Up to 10 processing procedures are sequentially executed. If it is determined in step s6 that the photoelectric volume pulse signal is not detected, step s7 is executed again.

In the judgment at step s7 at this time, since the processing procedure from step s6 to step s10 has already been repeated a plurality of times, the flag i is always larger than 1, so that the flag i s12
Is executed. In step s12, the systolic blood pressure is determined.

That is, in the sphygmomanometer of this embodiment, the air bag 1
When the pressure within 0d is pressurized at a constant speed, if the pressure Pn becomes larger than the systolic blood pressure value, the pulsation of the artery is suppressed by the pressure, and attention is paid to the fact that no displacement occurs in the optical distance sensor 12, The point in time at which the photoplethysmographic signal is no longer detected is determined as the systolic blood pressure of the subject.

In step s12, the systolic blood pressure is determined, and when its value is obtained, in step s13, the pump 24
Is stopped, the electromagnetic control valve 22 is opened to the atmosphere in step s14, and the air in the air bag 10d is rapidly exhausted, and the procedure ends.

On the other hand, apart from the above procedure, when the constant speed pressurization of the air bag 10d is started in step s4, step s1
At 5, it is always determined whether or not the pressure in the air bag 10d is larger than the initially set upper limit. At the same time as this determination, it is also determined in step s16 whether or not the measurement time has reached the limit. If it is determined that any of these has exceeded the limit, that fact is displayed on the display unit 38 in step s17, and The process proceeds to s13 and the measurement is stopped.

According to the sphygmomanometer of the present embodiment configured as described above, based on the photoelectric volume pulse wave signal transmitted from the optical distance sensor 12, the maximum and minimum blood pressures of the subject are determined by the digital data processing unit 14. Therefore, the local amount of displacement of the arterial wall can be directly measured, and the maximum and minimum blood pressure values can be obtained based on this displacement amount, so that accurate blood pressure value measurement is possible.

After the above processing is completed, the latter half processing for continuous blood pressure measurement shown in FIG. 4 is continuously performed. First, in step s20, the elasticity parameter k is calculated from the maximum and minimum blood pressure values obtained as a result of the measurement and the maximum and minimum displacement amounts of the arterial wall. The elasticity parameter k is given by the above-mentioned equation (3), and k = (Psys-Pdia) / (Rsys-Rdia).

Next, at step s21, the cuff pressure P is set. This cuff pressure P is about 8 times lower than the diastolic blood pressure Pdia.
The set pressure Pc is set to Pc = Pdia-8 to 10 (mmHg).

When the above setting is completed, step S22
To open the electromagnetic control valve 22, and in step 23, the cuff is boosted. As a result, if the cuff pressure P is equal to or slightly higher than the set pressure in step S24, the pressurization is stopped (the electromagnetic control valve 22 is stopped) in step s25. Then, while maintaining the pressure in that state, the volume pulse wave is detected in step s26,
At 27, the volume wave pulse is multiplied by the elasticity parameter k, and at step s28, the values are sequentially displayed in a graph on the display unit 38.

The above equation is obtained by modifying the above equation (3), and is given by (Pa−Pc) = k (Ra−Rc), where Pc is the diastolic blood pressure determined by the set cuff pressure. , Rc are the minimum volume wave pulses determined by the set cuff pressure.

FIG. 6 is a waveform diagram of continuous blood pressure provided with the above-mentioned calibration characteristics, and a continuous waveform similar to the arterial pressure waveform continuously measured by the catheter method shown in FIG. 7A can be obtained. . In the figure, the vertical axis indicates blood pressure, the vertical axis indicates elapsed time, and the vertical axis is indicated by volt, which can be converted into pressure (mmHg) and displayed.
In this case, the systolic blood pressure is 200 mmH.
g, the diastolic blood pressure has a continuous waveform of 100 mmHg.

The above continuous waveform is a waveform obtained in a state where the cuff pressure is kept below the diastolic blood pressure of the subject, so that continuous measurement can be performed. It is necessary to determine the required time, and when the set measurement time has been reached in step s29, the electromagnetic control valve 22 is opened and rapid exhaust is performed in step s30, and the measurement is terminated.

In the above embodiment, the local displacement of the arterial wall is directly measured by the optical distance sensor, and the maximum and minimum blood pressure values are determined based on the displacement, and the elasticity parameter is determined from these values. Therefore, continuous blood pressure can be measured with high accuracy.

However, if the other Livarotch sphygmomanometer is capable of measuring the amount of displacement of the artery wall, after detecting the highest and lowest blood pressures, the processing procedure shown in FIG. 4 is executed. Of course, continuous blood pressure can be measured.

[0055]

As described above in detail in the embodiments,
According to the sphygmomanometer according to the present invention, the volume wave pulse measured in a state where the cuff pressure is kept lower than the diastolic blood pressure is corrected to an arterial pressure waveform and displayed continuously, and according to the setting of the cuff pressure,
Since it takes a considerable period of time for the subject to cause venous regurgitation, it is possible to perform continuous measurement in a non-invasive manner.

[Brief description of the drawings]

FIG. 1 is an overall configuration block diagram showing one embodiment of a sphygmomanometer according to the present invention.

FIG. 2 is a development view of a cuff of the sphygmomanometer and a cross-sectional view of a main part thereof.

FIG. 3 is a flowchart illustrating an example of a processing procedure for obtaining calibration data when measuring continuous blood pressure with the sphygmomanometer.

FIG. 4 is a flowchart illustrating an example of a processing procedure for measuring continuous blood pressure with the same sphygmomanometer following FIG. 3;

FIG. 5 is a waveform chart showing an example of a pulse wave detected in the processing procedure of FIG.

FIG. 6 is a waveform chart showing an example of continuous blood pressure detected in the processing procedure of FIG.

FIG. 7A is an arterial pressure waveform diagram continuously measured by a catheter method. (B) is a continuous waveform diagram corresponding to the pulsation of the brachial artery picked up by the optical distance sensor.

[Explanation of symbols]

 10 Cuff 12 Optical distance sensor 14 Digital data processing unit 38 Display unit

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Shigehiro Ishizuka 1-243 Asahi Kitamoto City, Saitama Prefecture A & D Development & Technology Center

Claims (2)

[Claims] 1. A cuff that is attached to a main part of a subject and inflates an artery by injecting air, a sensor that is installed opposite to the cuff and detects a pulsation displacement of the artery, and a pulse wave that the sensor sends out A sphygmomanometer provided with a digital data processing unit for determining the highest and lowest blood pressures of the subject based on the signal, wherein the digital data processing unit uses the pulsation and the highest and lowest blood pressures obtained in advance. Calculating means for calculating an elasticity parameter for giving a correlation with displacement; cuff pressure setting means for holding the cuff pressure at a pressure lower than the previously obtained minimum blood pressure; and cuff pressure detected based on the held cuff pressure. A sphygmomanometer, comprising: a conversion means for multiplying the volume wave pulse by the elasticity parameter to convert it into an arterial pressure waveform; and a display means for sequentially displaying the converted arterial pressure waveform. 2. The sensor according to claim 1, wherein the sensor is an optical distance sensor that is installed opposite to the cuff and detects a pulsating displacement of the artery. The sphygmomanometer according to claim 1, wherein a diastolic blood pressure is determined.