JP2001309895A - Sphygmomanometer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sphygmomanometer with which influence of stasis on measuring blood pressure is gauged and errors caused by stasis in sphygmomanometry is prevented. SOLUTION: A sphygmomanometer is provided with a sensor for venous pressure, which detects venous pressure at a peripheral part rather than a part where a cuff is attached. After increasing pressure of the external pressure of the cuff (ST1-ST3), cuff pressure, Korotokoff sound, and venous pressure are measured (ST5) during the process (ST4-ST6) of slowly reducing the external pressure of the cuff. Systolic blood pressure and diastolic blood pressure are found from cuff pressure at the beginning and the end of Korotokoff sound tentatively (ST7), and the maximum value of peripheral venous pressure at the time of measuring blood pressure is computed (ST8). Whether the difference between diastolic blood pressure and the peripheral venous pressure is less than the value, which has been set up, is determined (ST9). If the difference is determined to be less than the value, which has been set up, the manometer informs to measure blood pressure again.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a sphygmomanometer for measuring blood pressure non-invasively.

[0002]

2. Description of the Related Art Conventionally, non-invasive blood pressure measurement methods include a technique in which a cuff is used to compress an artery, a Korotkoff sound is detected by a stethoscope in a decompression process after hemostasis, and a cuff pressure when the Korotkoff sound is generated and disappears. Is read with a mercury meter, auscultation method to measure systolic blood pressure, diastolic blood pressure, and Korotkoff sound is detected by K sound sensor,
An electronic Korotkoff sound method for measuring blood pressure from the cuff pressure at that time, and an oscillometric method for detecting a pulse wave component superimposed on the cuff pressure and determining the blood pressure from this pulse wave component and the cuff pressure are generally used. It has been implemented.

[0003]

However, in the conventional auscultation blood pressure measuring method, it is recommended that (1) the decompression speed of the arm band be 2-3 mmHg / sec. At this rate of decompression, congestion is likely to occur in the periphery. (2) When peripheral congestion occurs, the Korotkoff sound decreases. (3) It is difficult to know the degree of congestion from the appearance. Therefore, there is a risk that peripheral congestion may occur and the diastolic blood pressure value may be overestimated, and the occurrence cannot be detected.

The present invention has been made in view of the above problems, and has as its object to provide a sphygmomanometer capable of measuring the influence of blood stasis on blood pressure measurement and preventing erroneous blood pressure measurement due to stasis. I have.

[0005]

A sphygmomanometer according to the present invention comprises an arm band for pressing a living body to stop bleeding, a pressurizing unit for pressurizing an arm, and a pressure measuring unit for measuring a pressure in the arm band. Blood pressure information extracting means for extracting blood vessel information during the pressurizing or depressurizing process; blood pressure determining means for determining blood pressure based on the obtained pressure and blood vessel information; and venous pressure for measuring relative venous pressure on the distal side from the arm band. Measuring means, means for determining whether or not the difference between the arterial pressure value and the peripheral venous pressure of the cuff at the time of blood pressure measurement is smaller than a predetermined value, and the reliability of the blood pressure measurement value when the difference is smaller than the predetermined value. And a notifying means for notifying that there is a question.

In this sphygmomanometer, when measuring the blood pressure in the arterial hemostasis using the arm band, the relative pressure of the vein is measured on the peripheral side from the arm band,
It is determined whether or not the difference between the arterial pressure value and the vein relative pressure is equal to or less than a predetermined value. By this notification, the measurer can know that congestion is occurring in the periphery.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in more detail with reference to embodiments. FIG. 1 is a block diagram showing a circuit configuration of an electronic sphygmomanometer according to the present invention. The electronic sphygmomanometer according to this embodiment is wound around an arm, a cuff 1 for stopping an artery by pressurization, and a K for detecting a Korotkoff sound.
Sound sensor 2 and pressure sensor 3 for detecting pressure in cuff 1
A pressurizing pump 4 for pressurizing the cuff 1, a slow exhaust valve 5, a rapid exhaust valve 6, an input unit 7 having a power switch, a measurement start switch, and the like, and a measured systolic blood pressure, diastolic blood pressure, and the like. A display unit 8 for displaying, a CPU 9 for executing a processing operation for measurement, and a peripheral venous pressure sensor 10 for detecting a venous pressure on a more peripheral side than the arm band attachment unit are provided. However, components other than the peripheral venous pressure sensor 10 are conventionally provided in an electronic sphygmomanometer of the K-tone method, and are not particularly novel in terms of hardware. When the K sound sensor 2, the pressure sensor 3, and the like are taken into the CPU 9, signal conversion may be performed using a filter, an amplifier, an A / D converter, or the like, but this is omitted here.

In an electronic sphygmomanometer adopting the K-tone method as in this embodiment, generally, a pressurizing pump is turned on to pressurize the arm band 1 to a predetermined pressure, and thereafter, a very slow depressurizing process is performed.
The sound sensor 2 detects the occurrence and disappearance of the Korotkoff sound, and determines the arm band pressure at the point where the Korotkoff sound is generated as the systolic blood pressure (SYS) and the arm band pressure at the time when the Korotkoff sound disappears as the diastolic blood pressure (DIA). .

However, looking at the state of the blood vessels at the time of measuring the blood pressure, as shown in FIG. 4, when the arm band 1 is pressurized to the pressurization set value, both the artery BA and the vein BV are closed. is there. When the decompression gradually progresses and the arm band pressure becomes lower than the systolic blood pressure, the artery opens only during the period when the arterial pressure exceeds the arm band pressure, and the artery closes during the period when the arterial pressure falls below the arm band pressure. A sound is generated. When the arm band pressure is close to the systolic blood pressure, the vein BV is still closed, and the amount of blood sent from the arm band wearing section to the peripheral section increases. As this continues, the peripheral venous pressure becomes relatively large. Then, congestion occurs, the difference between the diastolic blood pressure and the peripheral venous pressure becomes small, and the Korotkoff sound also becomes small. As a result, the Korotkoff sound disappears quickly, and the diastolic blood pressure is overestimated.

As described above, when congestion occurs, erroneous measurement occurs only with the conventional K-tone method. Therefore, in the electronic blood pressure monitor of this embodiment, the peripheral vein pressure is measured non-invasively by the peripheral vein pressure sensor 10 to avoid the influence of blood stasis on blood pressure measurement. As the peripheral vein pressure sensor 10, for example, as shown in FIG. 5, a band-shaped strain gauge type connected to the main body of the sphygmomanometer is mounted on the wrist. In addition, as shown in FIG. 6, the pressure sensor 10a may be fixed to the wrist by the sensor fixture 13. Further, a photoelectric sensor may be used as the peripheral vein pressure sensor 10.

In this embodiment, as shown in FIG. 7 (a), after the arm band 1 is pressurized to the pressurization target value, the pressure is gradually reduced while the peripheral vein pressure sensor 10 detects the peripheral intravenous pressure ( Relative pressure). While the vein is closed, the peripheral venous pressure rises because the blood flow is sent to the periphery as the arm band pressure decreases, but eventually the arm band pressure and the intravenous pressure balance, the peripheral venous pressure becomes maximum, and the arm The vein under the zonal pressure opens, and thereafter both decrease while remaining in balance. FIG.
In the (a) to show the equilibrium period T _B, there is a correlation cuff pressure and venous pressure (relative pressure), as shown in FIG. 7 (b), is between them expressed by y = ax + b. Therefore, using this equation, the arm band pressure (absolute value) is converted from the intravenous pressure (relative value). That is, as shown in FIG. 7C, the peripheral venous pressure (absolute value) can be obtained.

The maximum value of the peripheral venous pressure is the diastolic blood pressure DIA.
In some cases. Therefore, in the electronic sphygmomanometer of this embodiment, the difference between the diastolic blood pressure and the peripheral venous pressure is obtained, and if the difference is smaller than a predetermined value, the fact is notified.

Next, referring to the flowcharts shown in FIGS. 2 and 3,
The processing operation of the electronic sphygmomanometer according to the embodiment of the present invention will be described.
When the measurement start switch of the input unit 8 is turned on, the pressurizing pump 4 is turned on by a command from the CPU 9 to start pressurizing the cuff 1 (step ST1). Also, a pressurization set value is set (step ST2). When the pressurization is performed up to the pressurization set value, the pressurization is terminated (step ST3), and the slow depressurization is started (step ST4). The cuff pressure captured by the pressure sensor 3, the Korotkoff sound captured by the K sound sensor 2, and the peripheral venous pressure captured by the peripheral venous pressure sensor 10 are measured in the process of this slow pressure reduction (step ST).
5). The cuff pressure at the time of Korotkoff sound output is stored. When the Korotkoff sound is generated during the slow depressurization process and eventually disappears, the slow depressurization is terminated (step ST6), and the rapid exhaust is performed. The cuff pressure at the time of Korotkoff sound generation is provisionally determined as systolic blood pressure, and the cuff pressure at the time of Korotkoff sound disappearance is determined as diastolic blood pressure (step ST7). Further, the maximum value of the peripheral venous pressure is calculated (step ST8), and it is determined whether the difference between the diastolic (lowest) blood pressure and the peripheral venous pressure is smaller than a predetermined value (step ST9).
If the determination is NO, the provisionally determined blood pressure value is determined as the measured value (step ST10). The determination in step ST9 is YE
In the case of S, a notification for prompting re-measurement is performed (step ST1).
0A). This notification is displayed on the display unit 7, but may be notified by a buzzer sound.

When the measurement start key of the input section 8 is operated again in response to the notification of the re-measurement, the pressurization / decompression speed is set to increase (step ST11), and the pressurization pump 4 is turned on to start pressurization. (Step ST12). After that, as in the first measurement, when the pressure is increased to the set pressure value, the pressure pump 4 is turned off to end the pressure increase (step ST13), and the slow decompression is started at a higher speed than the previous time (step ST1).
4). Cuff pressure measurement, Korotkoff sound measurement,
The peripheral venous pressure is measured (step ST15), and the slow speed decompression is ended (step ST16). Then, the systolic blood pressure and the diastolic blood pressure are provisionally determined by the Korotkoff sound method (step ST).
17), calculate the maximum value of the peripheral venous pressure (step ST)
18). Then, it is determined whether or not the difference between the diastolic blood pressure and the peripheral venous pressure is smaller than a predetermined value (step ST19).
If the determination is NO, that is, if the difference value is equal to or greater than the predetermined value, the temporarily determined blood pressure value is determined as the measured value (step ST2).
0). If the determination in step ST19 is YES, that is, if the difference value is smaller than the predetermined value, a measurement error is notified (step ST21). This notification is also displayed on the display unit 7. The buzzer may be sounded in a manner different from the remeasurement.

Another Embodiment An electronic sphygmomanometer according to another embodiment in which peripheral venous pressure is used for a photoelectric sensor will be described. First, as shown in FIG. 8A, the peripheral vein pressure (relative value) is measured by the peripheral vein photoelectric sensor over time in the process of slowly decreasing the arm band pressure. Then, the peak point of the peripheral venous pressure (relative value) is obtained. At this peak point, the intra-armband pressure and the peripheral venous pressure are balanced, and thereafter, the balance remains unchanged with the decompression. Therefore, the armband pressure at this point can be determined as the maximum value of the peripheral venous pressure.

Further, as another embodiment of the electronic blood pressure monitor,
A physical quantity corresponding to the blood volume at the center of the arm band may be measured. As shown in FIG. 8 (b), in the process of slow decompression of the arm band, when a point where the arm band pressure and the peripheral venous pressure are balanced by the decrease of the arm band pressure is reached, the previously closed vein opens, The blood volume in the central part of the cuff rapidly increases. This is shown in FIG. 9 by a photoelectric sensor 14 including a light emitting element 14a and a light receiving element 14b.
In measured, the cuff pressure at increasing points P ₁ due to increased blood volume and peripheral vein.

As another physical quantity corresponding to the venous blood volume, impedance measurement may be performed by using 15a, 15b, 15c, and 15d shown in FIG. 10, or Doppler measurement may be used. These focus on the fact that the maximum value of the intravenous pressure in the decompression measurement is equal to the armband pressure at the point where the vein under the armband starts to open. Detection methods for P ₁ point shown in FIG. 8 (b), as shown in (c) of FIG. 8, by differentiating the signal of the physical quantity change of (b) in FIG. 8, also seek the maximum point good.

In the above-described electronic blood pressure monitor, the pressurizing speed and the depressurizing speed are increased by re-measurement.
Instead of this, as another embodiment, the pressure measurement method may be switched from the reduced pressure measurement method to the blood pressure measurement using the slow speed pressurization, that is, the pressure measurement method at the time of re-measurement. This is because the degree of occurrence of congestion is smaller in pressure measurement than in pressure measurement.

Although the electronic sphygmomanometer according to the above embodiment employs a measurement method based on the Korotkoff sound method, the present invention can also be applied to an electronic sphygmomanometer using an oscillometric method.

[0020]

According to the present invention, when the difference between the diastolic blood pressure and the peripheral venous pressure is smaller than a predetermined value, a notification that congestion is occurring is given, which affects the measurement of the congestion state. Whether or not there is can be detected objectively. In addition, erroneous measurement of blood pressure due to congestion can be prevented.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of an electronic sphygmomanometer according to an embodiment of the present invention.

FIG. 2 is a flowchart illustrating an initial measurement processing operation of the electronic blood pressure monitor of the embodiment.

FIG. 3 is a flowchart for explaining a measurement processing operation at the time of re-measurement of the electronic blood pressure monitor of the embodiment.

FIG. 4 is a schematic diagram of a measurement system for explaining a principle of adoption of the electronic blood pressure monitor of the embodiment.

FIG. 5 is a diagram illustrating an example of a peripheral venous pressure sensor used in the electronic blood pressure monitor of the embodiment.

FIG. 6 is a diagram illustrating another example of a peripheral vein pressure sensor used in the electronic blood pressure monitor of the embodiment.

FIG. 7 is a view for explaining the relationship between the arm band pressure, the measured blood pressure, and the peripheral venous pressure in the blood pressure measurement in the very slow pressure reduction process of the electronic blood pressure monitor of the embodiment.

FIG. 8 is a view for explaining measurement of peripheral venous pressure in a slow depressurizing process of an electronic blood pressure monitor according to another embodiment of the present invention.

FIG. 9 is a diagram showing an arrangement of photoelectric sensors when measuring peripheral venous pressure based on a change in blood volume at the center of the arm band.

FIG. 10 is a diagram illustrating another example of a sensor for measuring peripheral venous pressure based on a change in blood volume at the central portion of a cuff.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cuff 2 K sound sensor 3 Pressure sensor 4 Pressurizing pump 5 Slow exhaust valve 6 Quick exhaust valve 7 Display unit 8 Input unit 9 CPU 10 Peripheral vein pressure sensor

Continuation of the front page F term (reference) 4C017 AA08 AB01 AB02 AC03 AD07 BC11 BD01 BD05 BD06 CC02 DD14 DE01 DE05 FF08

Claims (8)

[Claims] 1. A cuff for pressing a living body to stop bleeding, a pressurizing means for pressurizing the cuff, a pressure measuring means for measuring a pressure in the cuff, and blood vessel information in a pressurizing or depressurizing process. Extracting blood vessel information extracting means, obtained pressure, blood pressure determining means for determining blood pressure based on blood vessel information, venous pressure measuring means for measuring vein relative pressure on the distal side from the arm band, and measuring arterial pressure value and blood pressure A means for determining whether the difference in the peripheral venous pressure of the cuff is smaller than a predetermined value, and a notifying means for notifying that the reliability of the blood pressure measurement value is questionable if the difference is smaller than the predetermined value. A sphygmomanometer comprising: 2. A means for extracting a maximum value of the peripheral venous pressure measured by said peripheral venous pressure measuring means, and a difference between a diastolic blood pressure value and a maximum value of the peripheral venous pressure is smaller than a predetermined value. 2. The sphygmomanometer according to claim 1, further comprising: means for determining whether or not the difference is smaller than a predetermined value, and notifying means for notifying that the reliability of the diastolic blood pressure value is questionable if the difference is smaller than a predetermined value. 3. When the reliability of the blood pressure measurement is in doubt,
The sphygmomanometer according to claim 1 or 2, further comprising a display unit for prompting prevention of congestion. 4. The sphygmomanometer according to claim 1, wherein if the determination means determines that the blood pressure measurement value is questionable, re-measurement is urged. 5. The sphygmomanometer according to claim 4, wherein the pressure reduction speed of the arm band is reduced at a higher speed than the previous measurement during the pressure reduction measurement of the re-measurement. 6. The sphygmomanometer according to claim 4, wherein the pressurizing speed of the arm band is increased at the time of pressurizing the re-measurement at a higher speed than the previous measurement. 7. The sphygmomanometer according to claim 4, wherein the measurement method is switched to perform the measurement. 8. The sphygmomanometer according to claim 7, wherein the measurement method is switched to a pressure measurement method and the measurement is performed.