JPS63150052A - Electronic hemomanometer - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Field of Industrial Application This invention relates to an electronic blood pressure monitor, and more specifically, to determination of a re-inflation target value when the cuff is under-inflated.

(b) Conventional technology In general, this type of electronic blood pressure monitor supplies air from a pressure pump to a cuff wrapped around the arm, etc., pressurizes the inside of the cuff to a predetermined value to ischemize the blood in the arm, etc. Pressurized air is exhausted slowly from the exhaust valve, and during this exhaustion, the pressure inside the cuff is detected by a pressure sensor, and at the same time, the Korotkoff sound is detected, and the cuff pressure when the Korotkoff sound occurs and disappears is determined as the systolic blood pressure. and diastolic blood pressure value.

In addition, in electronic blood pressure monitors using the vibration method, the pulse wave component is detected from the output signal of the pressure sensor, its amplitude value is calculated, and the systolic blood pressure value and diastolic blood pressure value are determined from this amplitude value and cuff pressure. There is.

In each of the above-mentioned electronic blood pressure monitors, the cuff is pressurized to a predetermined value at the beginning of measurement, but since blood pressure values vary depending on the subject, this pressurization may be insufficient. If the cuff is not pressurized above the systolic blood pressure value, blood ischemia in the arm, etc. will be incomplete and blood pressure measurement will not be possible.

Therefore, known electronic blood pressure monitors are configured to detect this insufficient pressurization and perform re-pressurization. For example, in the case of the Korotkoff sound method, if the Korotkoff sound is detected within 2 seconds during the slow exhaust process after the end of pressurization, it is determined that the pressurization is insufficient. Then, re-pressurization is performed by setting a target value, for example, 30 mmHg higher than the initial pressurization target value.

On the other hand, in the case of the vibration method, when the pulse wave amplitude value after the end of pressurization is equal to or higher than a predetermined value (for example, 2.4 mmHg), it is determined that the pressurization is insufficient, and as before, re-applying the amount fixed by the -rhythm. Perform pressure.

(c) Problems to be solved by the invention In the above conventional electronic blood pressure monitor, the repressurization target value is fixed, so even after repressurization, the naorifu pressure remains below the systolic blood pressure value. There were cases where it happened. In this case,
In addition, re-pressurization was required, which lengthened the time from the start of pressurization to the end of measurement, causing congestion of blood in the part of the subject where the cuff was wrapped, and making it impossible to perform accurate measurements. In addition, there was an inconvenience that the time of being compressed by the cuff became longer, which increased the pain of the subject.

In particular, with electronic blood pressure monitors that do not have a pressurization value setting device (described later), the pressurization target value is fixed to an average value. The process must be repeated several times, and the above-mentioned inconvenience becomes even more noticeable.

The present invention has been made in view of the above-mentioned disadvantages, and an object of the present invention is to provide an electronic blood pressure monitor that can complete repressurization only once when repressurization is required, thereby shortening the measurement time.

(D) Means for Solving the Problems As a means for solving the above-mentioned disadvantages, the electronic blood pressure monitor of the present invention has the configuration described in the following sections (al to (J)).

(a) Cuff, pressurizing means for pressurizing the gas in the Cbl cuff, (C) exhaust means for exhausting the gas in the cuff, (d1 pressure detection means for detecting the gas pressure in the cuff, (e) pressure detection means for detecting the gas pressure in the cuff, Insufficient pressurization detection means for detecting insufficient pressurization of gas; (f) Pulse wave component detection means for detecting a pulse wave component from the output signal of the pressure detection means in item d1; (g) Pulse wave component detection means in the previous item. A pulse wave differentiating means for differentiating the pulse wave component obtained in (11) a repressurization target value determination unit that determines a repressurization target value based on the repressurization parameter obtained by the repressurization parameter calculation means in the previous section; means, fJl (blood pressure value determining means for determining a blood pressure value based on the gas pressure within the cuff detected by the pressure detecting means in item d1;

(e) Function: In the electronic blood pressure monitor of the present invention, after the cuff is pressurized to a predetermined cuff pressure by the pressurizing means, slow evacuation is started by the evacuation means. During this slow evacuation process, the insufficient pressurization detection means detects
It is determined whether the cuff is insufficiently pressurized.

When it is determined that the cuff is insufficiently pressurized, the pressurizing means re-inflates the cuff based on the re-compression target value calculated by the re-compression target value calculating means.

Then, slow evacuation by the evacuation means continues, and at this time, the blood pressure value determination means determines the systolic blood pressure value and the diastolic blood pressure value based on the cuff pressure detected by the pressure detection means.

The calculation of the repressurization amount is performed as follows.

First, in a slow evacuation process for determining insufficient pressurization of the cuff, a pulse wave component is detected by the pulse wave component detection means from the output signal of the pressure detection means. This pulse wave component is differentiated by a pulse wave differentiator.

Further, the maximum value and the minimum value are extracted from the pulse wave differentiation by the repressurization parameter calculation means, and the ratio of these values is calculated and used as the repressurization parameter R.

This recompression parameter R is a measure of whether the cuff pressure is close to the systolic blood pressure or the diastolic blood pressure. Therefore,
If the re-pressurization target value is determined based on this re-pressurization parameter R, an appropriate re-pressurization target value is determined, re-pressurization only needs to be performed once, and the time required for blood pressure measurement is shortened.

(F) Embodiment An embodiment of the present invention will be described below with reference to FIGS. 1 to 8.

In this embodiment, the present invention is applied to an electronic blood pressure monitor that determines blood pressure values using the Korotkoff sound method.

FIG. 4 is an external perspective view of the electronic blood pressure monitor 1 according to this embodiment.

2 is a cuff that is wrapped around the arm. A Korotkoff sound (hereinafter referred to as sound) sensor 12 is built into the cuff 2. The cuff 2 is connected to the main body 19 through a tube 3 integrated with the lead wire of the K sound sensor 12.

On the top surface of the main body 19, a display 11 consisting of a liquid crystal display, etc.
A pressurization value setter 16, a start switch 17, and a power switch 18 are provided. The pressurization setting device 16 is a slide switch, and is set to an appropriate pressurization target value (for example, 180 mm
)Ig) can be selected. Note that the pressurization value setting device 16 may be omitted.

FIG. 5 is a block diagram showing the air system and circuit configuration of this electronic blood pressure monitor 1.

At the tip of the tube 3, an exhaust valve (exhaust means) 4, a pressure pump (pressurization means) 5, and a pressure sensor (pressure detection means) 6 are installed.
is connected. The exhaust valve 4 has a function of exhausting the air within the cuff 2 at a rapid rate or at a very low speed. The exhaust valve 4 and the pressurizing pump 5 are controlled by an MPU (microcomputer) 10, which will be described later.

As the pressure sensor 6, a semiconductor pressure conversion element or the like is used.

The output signal of this pressure sensor 6 is amplified by an amplifier (AMP) 7, and an analog/digital (A/D) converter 9
is input. Further, a part of the output signal from the amplifier 7 is input to the A/D converter 9 via a bandpass filter (pulse wave component detection means, BPF) 8. This A/D converter 9 is
It is connected to MPU10.

On the other hand, the output signal of the K sound sensor 12 is amplified by an amplifier 13, and then separated into Korotkoff sounds by a bandpass filter 14, which is input to a sound classifier 15. The K sound discriminator 15 determines the presence or absence of a K sound, and if a K sound is detected, it is manually transmitted to the MPU 10 to that effect.

MPU10 has a function of determining insufficient pressurization, a function of differentiating pulse wave components, and detecting maximum and minimum values from pulse wave differentiation.
It includes a function to calculate a re-pressurization parameter, a function to calculate a re-pressurization target value from the re-pressurization parameter, a function to determine a blood pressure value, etc.

A display 11 and a pressurization value setting device 16 are also connected to this MPU 10.

Next, the operation of the electronic blood pressure monitor 1 of this embodiment will be explained below, mainly with reference to FIGS. 1 to 3.

First, the cuff 2 is wrapped around the upper arm of the subject, and the initial pressurization target value Pco is selected using the pressurization value setter 16. When the start switch 17 is pressed in this state, the pressurizing pump 5 starts pressurizing the cuff 2 based on the command from MPU10.
Step (hereinafter referred to as ST) 1, see Figure 1].

In the next Sr1, the MPU10 takes in the cuff pressure Pc from the A/D converter 9, and this is the target pressurization value Pc.

Determine whether it has been reached. Cuff pressure Pc is pressurization target value P
This process of Sr1 is repeated until reaching co.

When the determination of Sr1 becomes YES, the MPU 10 stops the pressurizing pump 5 and sets the cuff pressure Pc at this time to SYS.

(Sr3). Then, based on the command from MPU10, the exhaust valve 4 starts exhausting at a slow speed (Sr1).

Subsequently, the timer T starts counting (5T5), and pulse wave signal processing (Sr6) is performed. Timer T1 in ST7
Pulse wave signal processing of Sr1 is repeated until time-up occurs. In this embodiment, timer T is set to 3 seconds.

To explain the details of the pulse wave signal processing of Sr1 (see Fig. 2), first, counting of timer T is started (Sr6
1), this timer T3 is set to lQmsec.

Next, the pulse wave signal value p is taken into the MPU10 from the A/D converter 9 (Sr62).

As shown in FIG. 6, the pulse wave appears as the cuff pressure Pc decreases, and is included in the output signal of the pressure sensor 6. This pulse wave is detected by the bandpass filter 8 from the output signal of the pressure sensor 6. FIG. 7 is an example of the waveform of the detected pulse wave signal.

Subsequently, at 5T63, the pulse wave signal is differentiated.

In this differentiation process, the pulse wave signal value is p, and the pulse wave differential value is pd.
Then, pd = 0.729p 'd+0.864(p - p
')...It is expressed as (1). Here, p+
, p ld are the previous pulse wave signal value and pulse wave differential value, respectively. Note that the above equation (1) corresponds to first-order bypass filter processing with a cutoff frequency of 5 Hz.

In 5T64, the pulse wave differential value pd obtained in 5T63 is
Maximum pulse wave differential value pdMa in pulse wave processing up to the previous time
compared with x. When pd is greater than pd-ax, p
Set dmax to this pd (5T65) and proceed to the process of 5T66. When pd is less than I) d,,ax, directly 5
The process advances to T66.

In 5T66, the pulse wave differential value pd obtained in 5T63 is
Minimum pulse wave differential value pd+- in pulse wave processing up to the previous time
compared with i-. When pd is less than pdsin,
Let pd,i be this pd (5T67) and proceed to the process of 5T68. When pd is more than pdmin, directly 5T
Proceed to step 68.

Note that pd□8, pdMi, . . . are set to zero when pressurization of Sr3 is stopped.

In 5T68, the repressurization parameter R is calculated by the following equation (2).

Subsequently, in Sr19, it is determined whether or not timer T has timed up. It waits at 5T69 until timer T3 times up. When it is determined that the timer T has timed up, the process moves to Sr7.

When it is determined in Sr7 that the timer T has timed up, the process proceeds to Sr1, where it is determined whether or not pressurization is insufficient. In this determination, the amplitude of the pulse wave is obtained from the data string of the pulse wave signal value p obtained in the process of Sr1, and when this is greater than a predetermined value, it is determined that the pressurization is insufficient. In addition, insufficient pressurization
The determination may be based on the time from the start of slow exhaust until the first sound is detected. Note that this invention does not involve detection of insufficient pressurization, so its details will be omitted.

If it is determined that there is no insufficient pressurization in Sr1, 5T1
Proceed to step 3. If Sr1 determines that there is insufficient pressurization, Sr1
Proceeding to the process r1, the re-pressurization target value Pcr is calculated.

Calculation of this repressurization target value Pcr is performed using the repressurization parameter R
It is carried out based on. As shown in FIG. 8, cuff pressure Pc
The closer the value of R is to the systolic blood pressure, the smaller the value of R becomes. Therefore, R
The smaller the repressurization is, the less repressurization is required, and the repressurization target value Pc
r is determined to be low.

The details of this Sr1 processing will be explained with reference to FIG.

In Sr11, it is first determined whether the repressurization parameter R is greater than 1.6. If R is greater than 1.6, at 5T92, Pcr=SYS+60 (mml1g) is set and the process returns to the main routine of FIG.

If R is determined to be less than 1.6 in Sr11, 5T
The process proceeds to step 93, where it is determined whether R is greater than 1.3. If it is determined that R is greater than 1.3, the process proceeds to 5T94, sets Pcr=SYS+45 (mml1g), and returns to the main routine. If it is determined in 5T93 that R is less than 1.3, the process proceeds to 5T95, sets Pcr=SYS+30 (mmtlg), and returns to the main routine.

At the next 5TIO, the pressurizing pump 5 operates again according to a command from MPU10, and repressurization is started.

Then, at 5TII, it is determined whether the cuff pressure Pc has reached the re-inflation target value Pcr.

If the cuff pressure Pc becomes larger than the re-inflation target value Pcr, the MP
The pressure pump 5 is stopped by the command from Ul0 (ST12
). Thereafter, a process for determining the systolic blood pressure value and the diastolic blood pressure value is performed. Note that, at this time as well, the exhaust valve 4 is performing slow exhaustion.

First, the process waits at 5T13 until the first sound is detected. If the K sound sensor 12 detects a sound and the input from the K sound discriminator 15 is in MPU10, the process proceeds to 5T14 and the cuff pressure Pc at that time is set to Sys. This SYS is
This is the subject's systolic blood pressure value.

Next, at 5T15, it is determined again whether or not the K sound has been detected. If a K sound is detected, proceed to 5716;
Timer T2 starts counting. Then, set the cuff pressure Pc at that time as the diastolic blood pressure value DIA and perform STI 7)
, return to STI 5.

Returning to 5T15, if K sound is not detected, 5
Proceeding to T18, it is determined whether or not timer T2 has timed up. If the determination is No, the process returns to 5TI5 again.

If the determination is YES, the process advances to 5719, where MPU10 displays sys and DIA on the display 11.

Normally, three or more K sounds are detected, but since the K sound for determining the diastolic blood pressure value is the last one, the above-mentioned processes 5T15 to 5T18 are repeated. Finally, the cuff pressure Pc at the time of sound detection is determined to be DIA,
It is displayed on the display 11 (ST19). Timer T2 is
This is to determine whether the last sound is a sound or not.

Finally (7) in ST20, by the MPU10 (7) command,
The exhaust valve 4 performs rapid exhaust, and the measurement ends.

In the above embodiment, the present invention is applied to a legal electronic blood pressure monitor, but it can also be applied to an electronic blood pressure monitor that uses the vibration method.

In this case, the K sound sensor 12, the K sound discriminator 15, etc. are not required.

(g) As described in detail of the invention, the electronic blood pressure monitor of the present invention detects the maximum value and minimum value of the pulse wave differential, determines the re-pressurization target value from the ratio of these, and performs re-pressurization. Since this method is performed repeatedly, the number of re-pressurizations is reduced and the measurement time can be shortened. Therefore, there is an advantage that blood congestion does not occur in the part of the subject around which the cuff is wrapped, and accurate measurements can be made, and the pain caused to the subject can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a flow diagram showing the operation of an electronic blood pressure monitor according to an embodiment of the present invention, FIG. 2 is a flow diagram showing pulse wave signal processing in the electronic blood pressure monitor, and FIG. 3 is a flow diagram showing the operation of the electronic blood pressure monitor. FIG. 4 is a flowchart showing the repressurization target value calculation process in the meter.
FIG. 5 is a block diagram showing the air system and circuit configuration of the electronic blood pressure monitor; FIG. 6 is a diagram showing the relationship between cuff pressure and time in the electronic blood pressure monitor; 7th
This figure shows an extracted pulse wave, and FIG. 8 is a diagram showing the relationship between cuff pressure and re-inflation parameters. 2: Cuff, 4: Exhaust valve, 5: Pressure pump, 6: Pressure sensor, 10: MPU, 11: Display. Patent applicant Tateishi Electric Co., Ltd. (and 1 others)
Name) Agent: Patent Attorney Shigeru Nakamura Figure 1 Figure 2 Figure 3 Figure 4

Claims (2)

[Claims] (1) A cuff, a pressurizing means for pressurizing the gas within the cuff, an exhaust means for exhausting the gas within the cuff, a pressure detecting means for detecting the gas pressure within the cuff, and a pressure detecting means for detecting the gas pressure within the cuff. a pressurization insufficient detection means for detecting insufficient pressurization; a pulse wave component detection means for detecting a pulse wave component from an output signal of the pressure detection means; and a pulse wave component detection means for differentiating the pulse wave component obtained by the pulse wave component detection means. A pulse wave differentiating means, and a recompression parameter that detects the maximum value and minimum value from the pulse wave differential value obtained by the pulse wave differentiator, calculates the ratio of these maximum values and minimum values, and uses the ratio as a recompression parameter. a calculation means, a re-pressurization target value determining means for determining a re-pressurization target value based on the re-pressurization parameter obtained by the re-pressurization parameter calculation means, and a gas in the cuff detected by the pressure detection means. An electronic blood pressure monitor comprising a blood pressure value determining means for determining a blood pressure value based on blood pressure. (2) The cuff is equipped with a Korotkoff sound sensor, and the blood pressure value determination means is equipped with a Korotkoff sound discrimination means to which the Korotkoff sound sensor is connected, and the blood pressure value is determined based on the presence or absence of the Korotkoff sound and the gas pressure in the cuff. An electronic blood pressure monitor according to claim 1, which determines a value.