JPS6247336A - 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 using a vibration method for measuring blood pressure values based on pulse wave amplitude values.

(b) Conventional technology In general, this type of electronic blood pressure monitor supplies pressurized air from a pressure pump to a cuff wrapped around the arm, etc., pressurizes the inside of the cuff to a predetermined value, and then performs blood ischemia in the arm, etc. Pressurized air is exhausted from the exhaust valve at a slow rate, and the pressure inside the cuff is simultaneously detected by a pressure sensor during this exhaustion.

Grooves are formed to extract pulse wave components from this pressure. Then, a pulse wave amplitude value is calculated by the CPU from this pulse wave component, and systolic and diastolic blood pressure values are calculated and displayed from this amplitude value and the cuff pressure.

Further, electronic blood pressure monitors using Korotkoff sounds measure and display blood pressure values from the time when the Korotkoff sounds occur and when they end, instead of the pulse wave component.

(c) Problems to be Solved by the Invention In each of the above-mentioned electronic blood pressure monitors, is the inside of the cuff pressurized to a predetermined value at the beginning of measurement?

Since blood pressure values vary depending on the person being measured, this pressurization may be insufficient. For example, if the pressure is not increased to the systolic blood pressure value, blood pressure measurement cannot be performed. Therefore, regarding this insufficient pressurization, in the case of the vibration method, the initially calculated pulse wave amplitude value is set to a predetermined value fij! (For example, 2.4
MH da) or above, or in the case of the Korotkoff sound method, when the Korotkoff sound was detected within 2 seconds after the end of the pressurization, it was determined that the pressurization was insufficient.

In the event of insufficient pressurization, conventionally, an error message was simply displayed to prompt re-measurement, or the pressure was re-pressurized to, for example, 30 MHg.

However, only this error message is displayed.

I could only understand the lack of pressure, but not the lack of pressure. In addition, when repressurizing to 30 mmHg, it is sometimes necessary to repressurize once again, which requires a long time for measurement.

This resulted in prolonged pain for the person being measured.

ii) a means of resolving the problem This invention has a cuff 1 as shown in FIG.

and a pressurizing means 2 for supplying pressurized air to the cuff 1.

Exhaust means 6 for slowly or rapidly exhausting the pressurized air inside the cuff, pressure detection means 4 for detecting the pressure inside the cuff 1, and pulse wave extraction means for extracting pulse wave components from the pressure inside the cuff 1. 5, an amplitude calculating means 6 for calculating a pulse wave amplitude value from the pulse wave signal of the pulse wave extracting means 5, and detecting insufficient pressurization of the cuff when the pulse wave amplitude value at the initial stage of calculation is equal to or higher than a predetermined value. a pressurization shortage detection means 7; a repressurization calculating means 8 for calculating the re-pressurization amount from the pulse wave amplitude value at the time of detecting the pressurization shortage and the cuff 1 pressure at the time of extracting the amplitude; The blood pressure calculation means 9 calculates the systolic and diastolic blood pressure values from the cuff pressure.

(E) Function The electronic blood pressure monitor of the present invention supplies pressurized air to the cuff 1 by the pressurizing means 2, and then quickly exhausts the pressurized air through the exhaust means 5 while the pressure detecting means 4 detects the pressurized air. At the same time as detecting the pressure inside the sicaf 1, a pulse wave component is extracted by the pulse wave extracting means 5, and a pulse wave amplitude value is calculated from the pulse wave signal of the pulse wave extracting means 5 by the amplitude calculating means B. When the initial pulse wave amplitude value is greater than or equal to a predetermined value, the insufficient pressurization detection means 7 activates the cuff 1.
After that, the re-inflation calculating means 7 calculates the amount of re-inflation from the pulse wave amplitude value at the time of insufficient insufflation and the cuff pressure at the time of extracting the amplitude, and then re-inflates the cuff 1. After re-inflating the pressure, the pump is evacuated at a slow rate, and the blood pressure calculating means 9 calculates the maximum and diastolic blood pressure values from the pulse wave amplitude value and the cuff pressure.

(F) Example Hereinafter, an example of the present invention will be described in detail based on the drawings.

As shown in FIG. 2, the electronic blood pressure monitor 11 detects the pulse wave amplitude value while slowly exhausting the pressurized air supplied to the cuff 12, and measures the blood pressure value from this amplitude value. This is a blood pressure monitor that uses the vibration method.

This cuff 12 is wrapped around the upper arm or the like.

It is connected to a pressurizing pump 13 (pressurizing means) and an exhaust valve 14 (exhausting means) via an air pump 15. The pressurizing pump 13 supplies pressurized air to the cuff 12 to ischemize the upper arm and the like, while the exhaust valve 14 is configured to exhaust this pressurized air slowly or rapidly.

Furthermore, a pressure sensor 16 (pressure detection means) is linked to the cuff 12, and this pressure sensor 16 detects the pressure inside the cuff 12 and outputs a cuff pressure signal as shown in FIG. 3(a). It is configured. This cuff pressure signal is input as a digital signal to the CPU 19 via an amplifier 17 and an A/D converter 18, and is also input from the amplifier 17 to a bandpass filter 20. As shown in FIG. 3('b), the bandpass filter 20 is a pulse wave extraction means for extracting a pulse wave component from a cuff pressure signal, and is configured to output a pulse wave signal. This pulse wave signal is A/
It is input as a digital signal to the CPUI 9 via the D converter 18.

This CPU 19 has built-in memories such as RAM and ROM (not shown), and performs signal processing according to programs stored in this ROM to calculate pulse wave amplitude values, systolic blood pressure values, mean blood pressure values, diastolic blood pressure values, etc. is configured to do so. Further, this CPU 19 is configured to output a sampling signal a to the A/D converter 18 and output control signals S and C to the pressurizing pump 13 and the exhaust valve 14. While the cuff pressure signal etc. are read by this sampling signal a, the pressurization pump 16 stops driving,
The exhaust valve 14 performs rapid exhaustion at a very low speed. Furthermore, C.P.
A display 21 is connected to U19, and is configured to display the systolic and diastolic blood pressure values as well as the average blood pressure value.

Here, a method for determining the systolic and diastolic blood pressure values will be explained.

This electronic blood pressure monitor 11 employs a vibration method.

Pulse wave signal obtained by bandpass filter 20 [Fig. 3 (
b)] Calculate the pulse wave amplitude value [for example.

See Figure 4 (1))]. Which amplitude value is used to determine the blood pressure value? For example, each blood pressure value is as follows.

Average blood pressure value: Point where the pulse wave amplitude value is maximum ApmaxO Cuff pressure Systolic blood pressure value: In the area where the cuff pressure is higher than the average blood pressure value (increasing process of pulse wave amplitude value), the pulse wave amplitude value is the maximum amplitude value A p Cuff pressure P sys diastolic blood pressure value at point M which is 50% of max: In the region where the cuff pressure is lower than the average blood pressure value (falling process of pulse wave amplitude value), the pulse wave amplitude value is equal to the maximum amplitude value A p mnx Cuff Pressure PDLA at 70% Next, the configuration and operation of this electronic blood pressure monitor 1 will be explained based on the flowcharts shown in FIGS. 5 and 6. Note that the step is called ST.

First, as shown in FIG. 5, when measurement is started in the STI, a control signal is output from the CPU 19 to drive the pressurization bonder 13 and supply pressurized air to the cuff 12. The pressure sensor 16 detects the pressure inside the cuff 12, and when it reaches a predetermined cuff pressure (ST2), the CPU 19 outputs control signals S, C, and stops the pressurizing pump 13 (ST3).

The exhaust valve 14 is opened and @speed exhaust is started (ST4).

Next, start the T2 timer and T1 timer (S
T5.6), T1 timer times up (ST7
) then (e.g. TI = 10~50m5eC)
, the CPU 19 outputs a sampling signal, reads the cuff pressure signal and the pulse wave signal, and samples the cuff pressure P and pulse wave Pu (ST8). The T2 timer sets a window that is a short time interval, for example, 1 to 2 seconds, and extracts the pulse wave amplitude value for each window. When this T2 timer times up (ST9),
At 5T10, a pulse wave amplitude value Ap is calculated from the maximum value Pumax and minimum value Putnin of the pulse wave signals within one window based on the formula 0 (amplitude calculation means).

Ap== Pumax-Pum1n --=-0 Next, determine whether the measurement flag is 1 or not (5T11)
, If No, the process moves to 5T12, and it is determined whether or not the pulse wave amplitude value Ap is larger than the reference value α. If it is smaller, a measurement flag is set (ST13), and the process returns to ST5.
Calculate the next pulse wave amplitude value. In other words, 5T12 means that when the first calculated pulse wave amplitude value Ap is greater than or equal to the reference value α, the cuff 1
It is a pressurizing insufficient detection means for detecting the insufficient pressurization of 2, and α is in the range of 1.5 to 31 nHg.
is set to .

When the cuff 12 is sufficiently pressurized, move to 5T11 to 5T14, set an increasing flag when the pulse wave amplitude value Ap is increasing (ST15), return to ST5, and sequentially press the cuff 12. The pressure P and amplitude value Ap are stored.

Then, when this amplitude value Ap starts to decrease and the increasing flag is 1 (ST16), the maximum value Ap of the pulse wave amplitude value
Let's extract mnx 5T17), its maximum value A p
The cuff pressure P corresponding to the 50% amplitude value of mnx is determined as the systolic blood pressure value Psys (ST18, blood pressure calculation means).

Next, return to ST5 and check the cuff pressure P and pulse wave amplitude value Ap again.
is extracted, and the falling amplitude value Ap is the maximum value A p max
When it becomes 70% or less (ST19), the corresponding cuff pressure P is determined to be the diastolic blood pressure value PDI (ST20, blood pressure calculation means). After that, the systolic blood pressure value PSYS is displayed on the 1 display 21.
, diastolic blood pressure value PDI, etc. 5T21).

Fully open the exhaust valve 14 to quickly exhaust the pressurized air inside the cuff 12 (5T22). Finish the measurement.

Next, the case of insufficient pressurization at 5T12 will be explained.

As shown in Fig. 7(a), α)), the envelope curve of the pulse wave amplitude value Ap usually takes on a mountain shape. Therefore, when the initial amplitude value Ap is larger than α, the cuff pressure P is small. I'm sure it has started. Therefore, in case A pressurized to 190MHy, since Apl is smaller than α, 5T1
Judgment 2 is No, which means that the cuff pressure PA is sufficiently pressurized. However.

1601! Key pressurized to ILHy, B,
In case C, which is pressurized to 145 mHf, the pulse wave amplitude values Ap5 and Ap7 are larger than α, so
The determination at 5T12 is YES, and the cuff pressures Pn and Pc are insufficient. The larger the pulse wave amplitude value Ap (Apl<Ap5<Ap7), the smaller the cuff pressure P (PA>PB>PC).

It can be seen that the amount of insufficient pressurization increases.

Therefore, as shown in FIGS. 4(a) and 4(b), when the initial pulse wave amplitude value Apl is larger than α, the process is shifted to 5T23.

The repressurization amount is calculated (repressurization calculation means). This repressurization amount ΔP is calculated from the 0 formula or the 0 formula.

△P = ApI XKI-PIXK2+ to 3...
...■Here, 1. 2. 3 is a preset value.For example, 1=15. 2=0.01. It is set to 3=5 side Hf.

After the repressurization amount △P is calculated from this 0 formula or 0 formula, 5
△P to the cuff pressure Pset initially set at T24.
A reset pressure P set AG is set to which P set AG is added.

Then, the system returns to 'STI', the pressurizing pump 15 is driven again, the cuff 12 is pressurized, and the above-mentioned measurement operation is performed.

Therefore, as shown in Figure 4 (n), the time change in cuff pressure P when re-inflating is as follows: it rises once, then falls to calculate the first pulse wave amplitude value Apl, and then re-inflates due to insufficient pressure. rise,
After that, it will gradually decline. Then, the pulse wave amplitude value Ap is calculated, and the systolic and diastolic blood pressure values Psys,
PDIA is calculated.

Next, the reason for deriving Equation 0 or Equation 0 will be explained.

Both formulas are designed to change the amount of re-inflation depending on the cuff pressure P corresponding to the pulse wave amplitude value Ap. The reason for this is to take into consideration not only healthy people with normal blood pressure, but also people with high blood pressure. As shown in FIGS. 8(a) and (b).

Case D is a case of a hypertensive person, Case E is a case of a healthy person,
It can be seen that after exhaustion, the pulse wave amplitude value Ap of a hypertensive person gradually becomes larger than that of a healthy person.

Moreover, FIG. 9 shows the relationship between the systolic blood pressure value PSYS and the pulse pressure (the difference between the systolic blood pressure value and the diastolic blood pressure value). From FIG. 9, there is a tendency that the higher the systolic blood pressure value, the higher the pulse pressure. The pulse pressure acts as a force that changes the arterial wall, and the greater the pressure, the greater the displacement of the arterial wall.

The amount of displacement is transmitted to the cuff 12 through muscles and skin,
It becomes a pulse wave. Therefore, the larger the pulse pressure, the larger the pulse wave, and the larger the pulse wave amplitude mAp.

The results shown in FIG. 9 and the results shown in FIG. 8 match. From these results, even if the initial pulse wave amplitude value Ap is the same, the cuff pressure P is large.

If a person has high blood pressure and exhausts the air at a slow rate as shown in FIG. 8, the pulse wave amplitude value Ap increases.

Therefore, it can be understood that since the average blood pressure value Apmax increases, the amount of repressurization decreases.

Therefore, the same pulse wave amplitude value Ap and the corresponding cuff pressure P
Equation 0 or Equation 0 has been statistically derived from the relationship with the systolic blood pressure value p sys and the like.

A specific example based on the 0 formula is shown in the table below.

(K1=15., 2=0.01., and 3=5) In this embodiment, the pressurizing pump 13 is automatically controlled, but nine manual pumps may be applied. At that time, the repressurization amount and the like are displayed on the display 21.

Furthermore, it goes without saying that the formula for calculating the repressurization amount ΔP is not limited to the embodiment.

(g) Effects of the invention As described above, according to the electronic blood pressure monitor of the present invention.

Since the amount of under-pressurization is calculated from the pulse wave amplitude value and the cuff pressure, the amount of re-pressurization becomes clear.

It is possible to prevent the measurement from taking a long time. Tsuyoshi.

This is because measurements can be performed by repressurizing at least once, so there is no need to repressurize many times, and the pain caused by ischemia can be shortened.

Blood pressure measurement can be easily performed.

Furthermore, in the case of 8 manual pressurization, the amount of re-pressurization can be known, so the pressurization operation is easy and erroneous measurements can be prevented.

[Brief explanation of drawings]

Figure 1 is a schematic diagram showing the configuration of this invention, Figures 2 to 9
The figures show one embodiment of the present invention, Fig. 2 is a block diagram of an electronic blood pressure monitor, Fig. 3 (a) is a waveform diagram of cuff pressure, Fig. 3 (a) is a waveform diagram of a pulse wave, and Fig. 4 ( a) is a waveform diagram of cuff pressure during re-inflation, Figure 4 (top) is a diagram of changes in pulse wave amplitude value, Figures 5 and 6 are flow diagrams of the electronic blood pressure monitor, Figure 7 (a)
is a waveform diagram of cuff pressure in various pressurization states, and Fig. 7 (b
) is a diagram of the change in the pulse wave amplitude value, Figure 8 (a) is a waveform diagram of the cuff pressure for different subjects, Figure 8 (crest) is a diagram of the change in the pulse wave amplitude value, and Figure 9 is a diagram of the change in the pulse wave amplitude value. It is a figure showing the relationship between a systolic blood pressure value and pulse pressure. 1.12: Cuff, 2.13: Pressurizing means. 5.14: Exhaust means, 4.16: Pressure detection means, 5
・20: Pulse wave extraction means. 6: Amplitude calculation means; 7: Insufficient pressurization detection means. 8: Repressurization calculation means; 9: Blood pressure calculation means. Patent Applicant Tateishi Electric Co., Ltd. Agent Patent Attorney Shigeru Nakamura Figure 6 N2 Figure 11: Den 3-fmliz+

Claims (1)

[Claims] (1) a cuff, a pressurizing means for supplying pressurized air to the cuff, an exhaust means for slowly or rapidly exhausting the pressurized air within the cuff, and a pressure detecting means for detecting the pressure within the cuff;
pulse wave extraction means for extracting a pulse wave component from the pressure within the cuff; amplitude calculation means for calculating a pulse wave amplitude value from the pulse wave signal of the pulse wave extraction means; and a pulse wave amplitude value at the initial stage of the calculation. insufficient pressurization detection means for detecting insufficient pressurization of the cuff when the value exceeds a value; and repressurization that calculates a re-pressurization amount from the pulse wave amplitude value and the cuff pressure at the time of extracting the amplitude when this insufficient pressurization is detected. An electronic blood pressure monitor comprising: a calculating means; and a blood pressure calculating means for calculating systolic and diastolic blood pressure values from the pulse wave amplitude value and cuff pressure.