JPH05212004A - Electronic sphygmometer - Google Patents

Abstract

PURPOSE:To provide the electronic sphygmometer which can estimate the max. blood pressure of even an arrhythmia patient with high accuracy, set the opti mum max. pressurization quantity and shorten the time for a blood pressure measurement. CONSTITUTION:Pressurization is started at a high speed and pulse wave periods are calculated in a pressurization process (ST41, ST42). The fluctuation REL- DLT-PI of the pulse wave periods is calculated (ST43 to ST48). The pressurization rate is adjusted to a low speed when the fluctuation REL-DLT-PI is larger than the threshold TH (ST49, ST50) and the pressurization rate is held at the high rate if the fluctuation is smaller than the threshold TH.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic sphygmomanometer, and more particularly to an electronic sphygmomanometer characterized by determining a pressurizing speed.

[0002]

2. Description of the Related Art An electronic sphygmomanometer applies pressure to a cuff (arm girdle) to squeeze a measurement site and pressurizes it to a predetermined pressurization target value. ) Or a pulse wave component, and determines the systolic blood pressure and the diastolic blood pressure from the blood vessel sound and the cuff pressure, or the pulse wave component and the cuff pressure.
In this type of electronic sphygmomanometer, in order to reliably detect the blood vessel sound and the pulse wave component in the depressurization process, it is necessary to set the pressurization target value to a pressure higher than the maximum blood pressure point by a predetermined pressure (pressurization margin). Therefore, conventionally, there is a sphygmomanometer that captures a blood vessel sound or a pulsation on the cuff pressure during pressurization, estimates the systolic blood pressure based on the pulsation, and sets the pressurization amount of the cuff. However, in the case of such a sphygmomanometer, the pressurizing speed of the cuff pressure greatly affects the accuracy of the estimation result of the systolic blood pressure.

For example, in the case of a method of determining a blood pressure value based on the presence or absence of a blood vessel sound, if the pressurization speed is too fast, the cuff is generated between the sound of the blood vessel of a certain pulse and the occurrence of the next pulse (pulse cycle). Since the pressure rises significantly, it is not possible to accurately detect the cuff pressure point where the blood vessel sound just disappears. In other words, the systolic blood pressure estimation error may occur by the amount of the cuff pressure that rises during the pulse cycle. In this method, the pulse wave is captured during the pressurization process, and the systolic blood pressure is estimated from the change in the amplitude.

On the other hand, if the pressurizing speed is slower than necessary, the pressurizing time becomes long, especially in hypertensive patients.
The total time for blood pressure measurement increases. Therefore, it is desirable that the pressurizing speed be fast within a range in which the estimation accuracy of the systolic blood pressure necessary for setting the pressurizing amount is maintained. From this perspective,
Generally, the pressurizing speed is appropriate to be about 20 to 30 mmHg / beat per second. In accordance with this, some electronic sphygmomanometers have a pressurizing means having a control function so that the pressurizing speed is adjusted based on the behavior of the cuff pressure for a fixed time after the start of pressurizing.

[0005]

In the conventional electronic sphygmomanometer described above, in the case of an arrhythmia patient, the pulse wave cycle changes from moment to moment, so that an arrhythmia occurs at the systolic blood pressure estimation point as described above. If suddenly becomes longer, an accurate estimated systolic blood pressure value cannot be obtained, and the amount of pressurization calculated based on such an estimated value does not provide proper pressurization, resulting in insufficient or insufficient pressurization. There is a problem in that squeezing occurs, and it takes inevitable measurement for a long time due to re-pressurization and unnecessary pressure on the measurer.

The present invention has been made in view of the above problems, and realizes highly accurate systolic blood pressure estimation even in arrhythmia patients, and shortens the blood pressure measurement time by setting the optimum pressurization amount. It is intended to provide a blood pressure monitor.

[0007]

The electronic sphygmomanometer of the present invention detects a cuff, a pressurizing means for pressurizing the cuff, a depressurizing means for reducing the internal pressure of the cuff, and a fluid pressure in the cuff. A pressure detecting means, a blood vessel information detecting means for detecting blood vessel information such as a pulse wave component or a blood vessel sound contained in the cuff pressure in the process of changing the cuff pressure, and blood vessel information detected by the blood vessel information detecting means and An electronic sphygmomanometer comprising a blood pressure value determining means for determining a systolic blood pressure value and a diastolic blood pressure value on the basis of an output signal of the pressure detecting means, and a pulse wave component disturbance degree detection for detecting the disturbance degree of the detected pulse wave component. Means and
A pressurizing speed control means for controlling the pressurizing speed by the pressurizing means according to the degree of the turbulence is provided.

In the case of an arrhythmic patient, this electronic sphygmomanometer may suddenly disturb the pulse wave period or the pulse wave amplitude. In this case, the pulse wave component disturbance degree detecting means detects the disturbance degree, and, for example, When the degree of turbulence is large, the pressurization speed control means lowers the pressurization speed, increases the number of captured pulse waves, and prevents deterioration in the accuracy of blood pressure estimation.

[0009]

The present invention will be described in more detail with reference to the following examples. <Example 1> In this example, the present invention is applied to an oscillometric sphygmomanometer, in particular, one that estimates the systolic blood pressure during pressurization.

As shown in FIG. 1, the sphygmomanometer of this embodiment has a cuff 1, a pump 2 for pressurizing, a rapid exhaust valve 3, a slow exhaust valve 4, a pressure sensor 5, a low-pass filter 6, and an A
The / D converter 7, the MPU 8 and the display 9 are included. The pump 2 is capable of adjusting the pressurizing speed under the control of the MPU 8. The output of the pressure sensor 5 is input to the A / D converter 7 via the low pass filter 6. The low pass filter 6 is provided to remove pressure noise generated from the pump 2 during pressurization. The pressure signal converted into a digital signal by the A / D converter 7 is taken into the MPU 8. The MPU 8 extracts the pulse wave component superimposed on the pressure signal from the A / D converter 7 and uses it for processing such as blood pressure determination described later. Further, the MPU 8 controls the pump 2, the rapid exhaust valve 3, the slow speed exhaust valve 4 and the like to control the cuff pressure, and gives a measurement result or the like to the display device 9 for display. In the blood pressure monitor of this embodiment, the pressurizing speed can be adjusted in two stages, high speed and low speed.

Next, the overall operation of the blood pressure monitor of this embodiment will be described with reference to the flow chart shown in FIG. First, when the operation is started by turning on the start switch, etc., the MPU
8 drives the pump 2 to start pressurization, and sets the pressurization speed flag V _- flg to 1 [step ST (hereinafter abbreviated as ST) 1]. Next, a pulse wave component is extracted from the cuff pressure data by pulse wave extraction processing (ST2). This is a high-pass filter implemented on a program.

Then, the pulse wave is divided and the pulse wave number n is incremented by 1 (ST3). Next, in ST4, V _- fl
It is judged whether g = 1 or not, that is, whether the current pressurizing speed is high speed, and if it is high speed (V _- flg = 1), the process proceeds to ST5, but if it is low speed (V _- flg = 0). If so, the process proceeds to ST6 without adjusting the pressurizing speed. In ST5, the process of adjusting the pressurizing speed is performed according to the variation of the pulse wave cycle. Details of the process of adjusting the pressurizing speed will be described later.

Next, it is judged whether or not blood pressure estimation (maximum blood pressure) is possible (ST6), and when it is possible, estimation processing of the maximum blood pressure is performed (ST7). Whether or not it is possible is judged by whether or not the pulse wave amplitude exceeds the maximum point. If you can not estimate ST2-ST
The process of 6 is repeated. After the blood pressure is estimated in ST7, a preset pressurization target value is compared with the cuff pressure at that time (ST8), and if the target value is reached, the next process ST9 is performed.
If not, go back to ST2 and go to ST
The processes of 2 to ST8 are repeated.

When proceeding to ST9, the MPU 8 stops pressurization,
The slow exhaust valve 4 is controlled at a preset depressurization speed to start exhaust. That is, decompression is started. After that, the process relating to blood pressure measurement is performed. First, the cuff pressure signal is constantly read (ST10), pulse wave extraction processing is performed in the same manner as during pressurization (ST11), and pulse wave break point detection processing is then performed (ST12). Next step ST1
If it is not, the processes of ST10 to ST12 are repeated. In ST13, the pulse wave is divided. And S
Move to T14.

When the processing enters ST14, blood pressure measurement processing (described later) is executed. Next, it is determined whether or not both the maximum and minimum blood pressures have been calculated (ST15). If both have been calculated, the process proceeds to the next step ST16. If not, the process returns to step ST10 and continues to steps ST10 to ST15. The process of is repeated. In ST16, the MPU 8 operates the quick exhaust valve 3 to remove the pressure in the cuff. On the other hand, the measurement result is displayed on the display 9 (ST17), and all the processes are completed.

Details of the blood pressure calculation processing in step ST14 will be described with reference to the flowchart shown in FIG. Here, it is assumed that the pulse wave break point is detected by the pulse wave detection process. The pulse wave number n, the systolic blood pressure SP, and the diastolic blood pressure DP are both initialized to 0. First, when the pulse wave number n is incremented by 1 (ST
21) Next, the pulse wave amplitude AMP (n) and the corresponding cuff pressure Pc (n) are calculated for the pulse wave (ST2).
2). Next, AMP (n) is compared with Amax (ST
23). Amax is a variable that gives the maximum value of the pulse wave amplitude detected so far. If AMP (n)> Ama
If it is x, it is determined that the envelope of the pulse wave amplitude sequence has not reached the maximum point yet, and the process branches to ST31, and AMP (n)
After substituting the value of into Amax, the process returns. On the other hand, S
If AMP (n) ≦ Amax at T23, it is determined that the envelope of the pulse wave amplitude sequence has already passed the maximum point and is in the process of decreasing, and the process proceeds to ST24, where the systolic blood pressure variable SP is 0? Determine whether or not. Here, if SP = 0, then S
Assuming that P is undecided, the SP calculation process of ST25 to ST28 is performed, but if SP is decided, the process proceeds to ST29.

When the process proceeds to ST25, the pulse wave counter j is first set to the current pulse wave number n. Next, the counter j is decremented by 1 (ST26), and the pulse wave amplitude AMP (j) designated by j is compared with the maximum value Amax. Here, if AMP (j) ≦ Amax × 0.5 (ST2
7) The corresponding cuff pressure PC (j) is set as the systolic blood pressure SP (ST28). Then return.

In ST29 and ST30, diastolic pressure (minimum blood pressure) calculation processing is performed. In ST29, pulse wave amplitude AMP
It is determined whether or not (n) has decreased below the DP calculation threshold value (here, Amax × 0.7), and AMP (n) ≦ Am
When ax becomes 0.7, the cuff pressure Pc (n) is set to the minimum blood pressure DP.
And returns (ST30). Next, the most characteristic adjustment of the pressurizing speed in this embodiment will be described. The functional configuration of the pressurizing speed adjusting means is as shown in FIG.
Means 31 for reading the pulse wave generation time and cuff pressure from the data storage, means 32 for calculating the pulse wave cycle, and means 33 for calculating the pulse wave basic cycle from the calculated pulse wave cycle,
Means 34 for calculating the pulse wave cycle variation, and means 35 for adjusting the pressurizing speed according to the calculated pulse wave cycle variation.
It consists of and.

Next, the pressurizing speed of ST5 in FIG.
The details of the adjustment process will be described with reference to the flowchart shown in FIG.
Reveal In the following processing, n is the pulse wave number R
EL _-DLT_-PI is the periodic deviation (absolute value) of the pulse wave,
EL_-DLT_-PI (i) is the period deviation of the second to sixth pulse waves
(Absolute value), TH is the threshold value of the periodic deviation of the pulse wave, V_-
flg indicates a flag of the pressurizing speed.

When the pressurization speed adjustment processing routine is entered, first, the time of pulse wave generation is read (ST41). In ST41, when two or more pulse waves are detected, the interval is calculated and stored in the memory. Next, in ST43, it is determined whether or not the pulse wave number captured up to now is 6 or more. If 6 or more, the process proceeds to ST44, and if it is less than 6, the process returns. Thus, in this embodiment, the total number of all pulse waves is 5
If the pressure is less than that, the speed of pressing is not adjusted.

In ST44, it is determined whether or not the current pulse wave number n is 6, and when n = 6, the process proceeds to ST45, but when not n = 6, that is, when it is 7 or more, the process proceeds to ST47. In ST45, the basic periods of the second to sixth pulse waves are calculated, and the process proceeds to ST46. In ST46, the variation REL _- DLT _- PI of each pulse wave is calculated from the pulse wave basic period, and the
The maximum value of the variation of each sixth pulse wave cycle is defined as the variation of the sixth pulse wave train.

In ST47, the basic period of the current pulse wave after the seventh pulse wave is calculated, and the process proceeds to ST48. In ST48, the variation of the pulse wave period is calculated from the pulse wave basic period. Each calculation method in ST45 to ST48 will be described in detail later. After calculation of ST46 or ST48, the process moves to ST49, and the fluctuation of the pulse wave period REL _- DLT
_- PI or is greater than the threshold value TH, determines how. If it is larger than the threshold value, the pressurizing speed is adjusted to a low speed (S
T50), and the pressurization speed flag V _- flg is set to 0 (ST
51), return. Thus, in this example,
Once the pressurizing speed is adjusted to a low speed, the pressurizing speed is kept low until the cuff pressure reaches the pressurization target value. When the variation around the pulse wave is less than or equal to the threshold value, the pressurization speed is not adjusted (remains high speed) and the flow returns.

The basic period in ST45 is calculated as follows. The average value of the cycles of the second to sixth pulse waves is taken. The pulse wave with the cycle closest to the average value is
Select from pulse wave. Within the range of ± 0.1 sec of the selected pulse wave period (Fig. 5
The pulse wave having the period (see) is selected from the second to sixth pulse waves.

The average value of the selected pulse waves is used as the basic period up to the sixth pulse wave. The basic period of the pulse wave in ST47 is calculated by the following method. The period of the seventh pulse wave is ± 0 .. of the basic period up to the sixth pulse wave.
If it is within the range of 1 sec, the average value obtained by adding the period of the seventh pulse wave is set as the basic period until the seventh pulse wave. If the period of the seventh pulse wave is outside the range of ± 0.1 sec of the basic period up to the sixth pulse wave, the basic period up to the sixth pulse wave is used as it is as the basic period up to the seventh pulse wave. (Used for calculating the variation in the cycle of the seventh pulse wave) (see FIG. 5).

Thereafter, the calculation of this basic cycle is performed until the last pulse wave. Further, the fluctuation of the pulse wave cycle is calculated from the pulse wave basic cycle PIo and the pulse wave cycle by the following equation, and the pulse wave cycle deviation REL _- DLT _- PI is calculated as the fluctuation of the pulse wave cycle.

[0026]

[Equation 1]

PI: Period of pulse wave PIo: Basic period of pulse wave (see FIG. 7) <Second Embodiment> Next, an electronic blood pressure monitor according to another embodiment of the present invention will be described. The hardware configuration of the electronic blood pressure monitor of this embodiment is the same as that shown in FIG. The overall operation of the electronic sphygmomanometer is the same as that shown in FIG. The feature of this embodiment lies in the method of adjusting the pressurizing speed in ST5 in FIG. In the process of pressurizing the cuff pressure, this example electronic sphygmomanometer uses the ratio of the amplitude deviations of the three pulse waves and the average value of the amplitudes for any three consecutive pulse waves of the pulse wave amplitude sequence to measure the arrhythmia. Is detected and the pressurizing speed is adjusted accordingly. As shown in FIG. 7, the functional configuration of the pressurizing speed adjusting portion of the electronic sphygmomanometer according to this embodiment is means 41 for reading the amplitude of the pulse wave and the cuff pressure from the data storage unit.
And a pulse wave amplitude characteristic amount calculation means 42 for calculating the characteristic amount of the pulse wave amplitude, and a means 43 for adjusting the pressurizing speed according to the calculated characteristic amount of the pulse wave amplitude.

Next, details of the adjusting process of the pressurizing speed of the electronic sphygmomanometer of this embodiment will be described with reference to the flow chart shown in FIG. In the following description, n is the current pulse wave number, R
Is the pulse wave amplitude deviation ratio, AV is the average value of the pulse wave amplitudes of the preceding and following three beats, TH1 is the pulse wave amplitude deviation ratio threshold value, TH
2 is the threshold value of the average value of the pulse wave amplitude of three beats before and after, V _- flg
Is a pressurization speed flag (low speed: V _- flg = 0, high speed: V
_- flg = a 1), S1 is a pulse wave amplitude deviation of the current pulse wave of the pulse wave before one beat of the current pulse wave front two beats, S2 is the amplitude of the current pulse wave and pulse wave of the current pulse before one beat The deviations are shown respectively.

When the routine for adjusting the pressurizing speed is entered, it is first judged whether or not the pulse wave number n captured so far is 4 or more (ST61). If it is 4 or more, the process proceeds to ST62, but if it is less than 4, To return. Therefore, when the pulse wave number is 3 or less in the pressurizing process, the pressurizing speed is not adjusted. ST6
Going to 2, the current pulse wave one beat before (n-1) is centered,
The deviations S1 and S2 of the amplitude of the two-beat pulse wave before and after that are calculated (see FIG. 8). Next, in ST63, it is determined whether the amplitude deviation S1 is larger than the amplitude deviation S2. If the amplitude deviation S1 is large, the deviation ratio R = S1 / S2 is calculated in ST64, and S
If the amplitude deviation S1 is less than S2 at T63, ST65
Then, the deviation ratio R = S2 / S1 is calculated. ST64
Alternatively, after calculating the deviation ratio R in ST65, ST66
Go to AV = [AMP (n-2) + AMP (n-1)
+ AMP (n)] / 3 is calculated, the average of three pulse waves before and after is calculated, and the process proceeds to ST67.

In ST67, the pulse wave amplitude deviation R is the threshold value TH.
It is determined whether it is larger than 1, and if it is larger, the process proceeds to ST69.
When the pulse wave amplitude deviation R is not larger than the threshold value TH1, S
In T68, it is determined whether the pulse wave amplitude average value AV is larger than the threshold value TH2, and if larger, the process proceeds to ST69.
Here, the determinations in ST67 and ST68 are performed for any three consecutive beats in the pulse wave amplitude sequence from large → small →
When there is a part that changes greatly, it is often the case that the degree of abnormality is high, such as arrhythmia, and in this case, the ratio R of the amplitude deviation and the average value AV of the pulse wave amplitude are noted to be greater than a predetermined value. It is a thing.

ST69 is a process when it is determined to be abnormal.
The pressurizing speed is adjusted from the high speed until then to the low speed.
It And the pressurization speed flag V_-Set flg to 0 (S
(T70) and returns. Once converted to low speed,
Pressurization speed flag V _-flg is set to 0
Then, after returning, the determination in ST4 of FIG. 2 becomes NO,
Since ST5 is skipped, the cuff pressure is applied as the pressurizing speed.
The speed remains low until the pressure target value is reached.

When the pulse wave amplitude average value AV is smaller than the threshold value TH2 in ST68, it is determined that there is no abnormality, and the flow returns without adjusting the pressurizing speed. In each of the above-described embodiments, the pressurizing speed is selectively set in two stages of high speed and low speed, but it may be switched in plural stages if necessary. Further, in the above embodiment, the electronic blood pressure monitor for measuring blood pressure by the vibration method is taken as an example, but the present invention extracts the pulse wave in the pressurizing process, controls the pressurizing speed, and uses the K sound method in the depressurizing process. It can also be applied to an electronic blood pressure monitor that measures blood pressure.

[0033]

According to the present invention, since the turbulence of the pulse wave component is detected during the pressurization process and the pressurization speed is controlled according to the degree of the turbulence, in the case of an arrhythmia patient, the By slowing down the pressure velocity, increasing the number of captured pulse waves to prevent deterioration of the estimation accuracy of systolic blood pressure, and setting the maximum amount of pressurization, re-pressurization,
There is an effect that the measurement time can be shortened by not performing the re-measurement.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an electronic sphygmomanometer in which the present invention is implemented.

FIG. 2 is a flowchart for explaining the overall operation of the electronic sphygmomanometer according to the embodiment of the present invention.

FIG. 3 is a flowchart for explaining the operation of blood pressure calculation processing of the electronic blood pressure monitor of the embodiment.

FIG. 4 is a block diagram showing a functional configuration for adjusting a pressurizing speed of the electronic blood pressure monitor of the embodiment.

FIG. 5 is a diagram illustrating calculation of a pulse wave basic cycle in the electronic blood pressure monitor of the embodiment.

FIG. 6 is a flow chart for explaining a pressurizing speed adjustment processing operation of the electronic blood pressure monitor of the embodiment.

FIG. 7 is a block diagram showing a functional configuration for adjusting a pressurizing speed of an electronic blood pressure monitor according to another embodiment of the present invention.

FIG. 8 is a diagram for explaining a ratio of amplitude deviations of pulse waves of three consecutive beats and calculation of an average value of pulse wave amplitude values in the electronic blood pressure monitor of the embodiment.

FIG. 9 is a flowchart for explaining a pressurizing speed adjustment processing operation in the electronic blood pressure monitor of the embodiment.

[Explanation of symbols]

 1 Cuff 2 Pump 3 Rapid exhaust valve 4 Fine speed exhaust valve 5 Pressure sensor 7 A / D converter 8 MPU

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Osamu Shirasaki 17 Chudoji Minami-cho, Shimogyo-ku, Kyoto Science Center Building Omron Life Science Research Institute Co., Ltd.

Claims (3)

[Claims] 1. A cuff, a pressurizing means for pressurizing the cuff, a depressurizing means for reducing the internal pressure of the cuff, a pressure detecting means for detecting a fluid pressure in the cuff, and a cuff pressure in a process of changing the cuff pressure. A blood vessel information detecting means for detecting blood vessel information such as a pulse wave component or blood vessel sound contained in the blood vessel information, and a maximum blood pressure value and a minimum blood pressure value based on the blood vessel information detected by the blood vessel information detecting means and the output signal of the pressure detecting means. In an electronic sphygmomanometer comprising a blood pressure value determining means for determining a blood pressure value, a pulse wave component disturbance degree detecting means for detecting a disturbance degree of the detected pulse wave component, and the pressurizing means according to the disturbance degree. An electronic sphygmomanometer comprising a pressurizing speed control means for controlling the pressurizing speed. 2. A cuff, a pressurizing means for pressurizing the cuff, a depressurizing means for depressurizing the pressure inside the cuff, a pressure detecting means for detecting a fluid pressure in the cuff, and a cuff pressure in a process of changing the cuff pressure. A blood vessel information detecting means for detecting blood vessel information such as a pulse wave component or blood vessel sound contained in the blood vessel information, and a maximum blood pressure value and a minimum blood pressure value based on the blood vessel information detected by the blood vessel information detecting means and the output signal of the pressure detecting means. In an electronic sphygmomanometer comprising a blood pressure value determining means for determining a blood pressure value, a pulsation cycle calculating means for calculating the pulsation cycle of the pulse wave component detected in the pressurization process, and some calculated pulsation cycle data A pulsation cycle variation calculation means for calculating the variation of the pulsation cycle based on, and a pressurization speed control means for controlling the pressurization speed by the pressurization means according to the calculated dispersion of the pulsation cycle, You Electronic blood pressure monitor. 3. A cuff, a pressurizing means for pressurizing the cuff, a depressurizing means for depressurizing the pressure inside the cuff, a pressure detecting means for detecting a fluid pressure in the cuff, and a cuff pressure during a process of changing the cuff pressure. A blood vessel information detecting means for detecting blood vessel information such as a pulse wave component or blood vessel sound contained in the blood vessel information, and a maximum blood pressure value and a minimum blood pressure value based on the blood vessel information detected by the blood vessel information detecting means and the output signal of the pressure detecting means. An electronic sphygmomanometer comprising a blood pressure value determining means for determining a blood pressure value, wherein a pulse wave amplitude turbulence degree for calculating a pulse wave amplitude turbulence degree based on some data of the pulse wave amplitude calculated in a pressurization process. An electronic sphygmomanometer comprising: a calculating means and a pressurizing speed control means for controlling the pressurizing speed by the pressurizing means according to the calculated degree of disturbance of the pulse wave amplitude.