JPS6179442A - Automatic blood pressure measuring method and apparatus - 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] [Technical Field of the Invention] The present invention relates to a non-invasive automatic blood pressure measurement method and device thereof, and in particular shortens the measurement process from measuring and determining the systolic blood pressure of a subject to near the diastolic blood pressure. The present invention relates to an automatic blood pressure measurement method and device that makes it possible.

[Prior art and its problems] The measurement process in conventional non-invasive automatic blood pressure monitors is to first steadily increase the cuff pressure to a set value (150 to 200 mHg), and then increase it at a constant rate ( In the process of decreasing the cuff pressure by 2 to 3 ■Hg/5ea), the systolic blood pressure and diastolic blood pressure were determined by continuous measurements in that section.

For this reason, the time required for blood pressure measurement depends on the subject's blood pressure value (pulse pressure), assuming the cuff pumping speed is constant.
Blood flow in this section is almost completely stopped, resulting in a state of depression, which often results in errors in determining the diastolic blood pressure. In addition, meaningful measurements are actually performed during a few heartbeats around the systolic and diastolic blood pressures, and measuring constant volume in other areas would actually take unnecessary measurement time. This not only caused pain to the patient, but also hindered the realization of high-speed measurement to capture short-term blood pressure fluctuations.

In addition, conventional automatic blood pressure monitors use diaphragm pumps, piston pumps, etc. as pressurizing means.
The noise emitted by the pressurizing means during each measurement caused stress not only to the test subjects but also to the people around them. Moreover, at night, this noise wakes patients on long-term blood pressure monitors from their sleep, resulting in the inconvenience that blood pressure dynamics during sleep cannot be captured.

[Object of the Invention] The present invention has been made in view of the above-mentioned drawbacks of the prior art, and its purpose is to shorten the constant volume measurement process up to around the diastolic blood pressure after determining the systolic blood pressure. By this,
An object of the present invention is to propose an automatic blood pressure measurement method and device that can quickly and accurately measure blood pressure.

Another object of the present invention is to provide an automatic blood pressure measuring device that eliminates cuff pressurization noise.

Another object of the present invention is to provide an automatic blood pressure measuring device that is small and lightweight and can be used continuously for long periods of time.

[Summary of the Invention] The automatic blood pressure measurement method of the great invention (±) In order to achieve the above object, a setting step of monitoring the Korotkoff sound signal during cuff pressurization and setting a predetermined value, and a step of setting the predetermined value by monitoring the Korotkoff sound signal during cuff pressurization; a systolic blood pressure determination step of determining systolic blood pressure based on the Korotkoff sound signal detected during constant speed decompression;

The outline thereof is to include a rapid pressure reduction step of rapidly reducing the cuff pressure after the systolic blood pressure determination to the predetermined value.

Furthermore, in order to achieve the above object, the automatic blood pressure measuring device of the present invention includes a pressurizing means for increasing cuff pressure, a first pressure reducing means for decreasing cuff pressure at a predetermined speed, and a second pressure reducing means for decreasing the pressure at a high speed; a pressure detecting means for detecting the cuff pressure; a sound detecting means for detecting the Korotkoff sound and outputting a sound signal; a setting means for monitoring a sound signal and setting a predetermined value; and a systolic blood pressure determining means for determining a systolic blood pressure based on the sound signal detected during activation of the first pressure reducing means after the pressurization is stopped. , the cuff pressure reduction control means is provided which energizes the second pressure reduction means based on the systolic blood pressure determination and reduces the cuff pressure to the predetermined value.

Preferably, when the setting means can predict the diastolic blood pressure value based on the sound signal, one aspect thereof is to set a value obtained by adding the first pressure value to the diastolic blood pressure value as the predetermined value.

Preferably, when the setting means cannot predict the diastolic blood pressure value by monitoring the sound signal, one of the steps is to set the predetermined value to a value obtained by subtracting the second pressure value from the cuff pressure at the time of determining the systolic blood pressure. It shall be the mode.

- Preferably, one aspect of the pressurizing means is a liquefied gas cylinder as a pressure source.

[Embodiment of the Invention] Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a block diagram showing an automatic blood pressure monitor according to an embodiment of the present invention. In FIG. 0, 1 is a cuff wrapped around the arm, 2 is a microphone for detecting Korotkoff sounds, and 3 is for detecting cuff pressure. And with cuff pressure to control? The main body, which is a pipe that connects the main bodies, is roughly divided into three parts. 4 is a pressure control unit that detects and controls cuff pressure, 5 is a Korotkoff sound detection unit that detects Korotkoff sounds, and 6 is a central processing unit (C
Further, numeral 7 is a display section for displaying the subject's systolic and diastolic blood pressure, etc., and is normally provided in the main body. Reference numeral 8 is a recording unit for recording systolic and diastolic blood pressure, etc., and is connected when automatic measurement is to be carried out over a long period of time.

The pressure control unit 4 includes a pressure source 9 consisting of a cylinder filled with liquefied oxygen or liquefied carbon dioxide (C02), or a cylinder filled with compressed air, etc., and a regulator 10 that adjusts the gas pressure output from the pressure source 9 to a constant level. , an air supply valve 11 for pressurizing the cuff, and a constant rate (2 to 3 mmH4/5) of cuff pressure.
a constant discharge valve 12 for reducing the pressure at ee), a sudden discharge valve 13 for rapidly reducing the cuff pressure, a pressure sensor 14 for detecting the cuff pressure and converting it into a t-air signal, and a pressure sensor 14 output. The reason why the present embodiment system, which consists of an A/D converter 15 that converts an analog signal into a digital signal, does not use a pump as the pressure source 9 is to eliminate pressurization noise at all.

Furthermore, the reason why a gas cylinder is used in place of a pump in this embodiment is that a pulsation-free increase characteristic can be easily obtained for the VA that increases the cuff pressure, and the advantage of linearly increasing the cuff pressure is as explained below. As will be clear, it is also possible to obtain a pressure source 9 that is small, lightweight, and has an extremely large vaporization capacity by preferably using a liquefied gas cylinder. When used, it can be used continuously about 100 times, and the cylinder can be installed so as not to put strain on the waist of the subject.

= The Rotnif sound detection unit 5 includes an amplifier 16 that pre-amplifies the weak sound signal detected by the microphone 2, and extracts each predetermined frequency component from the output signal of the amplifier 16 and compares the amplitude, thereby generating a sound corresponding to a Korotkoff sound. A sound filter 17 separates the signal, pulse-forms it, and outputs a sound signal k (hereinafter also referred to as K sound), and an amplitude signal component of blood vessel pulse pressure vibration included in the output signal of the pressure sensor 14. pulse filter 18 which separates the signal, pulse-forms it, and outputs a pulse synchronization signal m.
It consists of The pulse-synchronized signal m captures the expansion and contraction of the blood vessels compressed by the cuff when the pressure applied to the cuff is gradually reduced, and it is known that this signal generally appears earlier than the sound and disappears later. It is being Therefore, this amplitude signal component is extracted by the pulse filter 18 and used as a gate signal for detecting the K sound, thereby accurately detecting the weak K sound from the noise.

The CPU 6 is a ROM containing the processing program of this embodiment.
, a microprocessor for executing the program, a RAM necessary for data processing, a PIO for input/output of processed data, a tri-eight circuit for driving the supply/discharge valves 11 to 13, etc., and a block of the CPU 6. , various functions realized by executing the processing program are shown in blocks. To explain these functional blocks in detail, 19 is a control means that controls one part of the CPU 6;
20 is a pressure control means that reads the cuff pressure detection signal P output from the A/D converter 15 in a timely manner and controls the supply/discharge valves 11 to 13 to obtain a predetermined pressurization and depressurization state within the cuff; 21 is a pulse synchronization means; This is a blood pressure determination means for determining the systolic blood pressure and diastolic blood pressure of the subject by examining the sound signal k that appears and disappears within the signal m.

Sections 2 to 5 relate to the operating principle of the device E in this embodiment.
In Figure 0, which is a diagram showing one typical process of blood pressure measurement, when the air supply valve 11 opens, the cuff pressure starts to rise quickly and without pulsation from point a to point b. The CPU 6 monitors the sound during this interval and sets the cuff pressure at the time when the first sound Pk appears as the predicted systolic blood pressure PREIIIA of the subject. As the cuff pressure increases, the sound Pk2 appears at almost constant intervals.
゜Pk3... is detected. Based on this cycle, the CPU 6 determines the maximum time interval t at which the next sound should appear, and confirms if there is a sound within that interval.

Once the cuff pressure exceeds the subject's systolic blood pressure, the sound disappears, but the CPU 6 sets the cuff pressure at the time when the last sound Pkn appears as the subject's predicted systolic blood pressure PRESYS, and at the same time waits for a predetermined period of time. The air supply valve 11 is closed when no sound is generated.

The cuff pressure at this point is the optimal pressurization point b (PRESYS+α) that enables rapid measurement of the subsequent systolic blood pressure. In this example, a liquefied gas cylinder is used as the pressure source 9, so the cuff pressure does not increase. Since it does not contain any pulsating components, it is possible to accurately detect even the weakest sounds in this section without worrying about noise entering the microphone.

Therefore, we monitor the onset and disappearance of the sound while the cuff pressure is rising, and based on this we provide a guideline for the subject's systolic and diastolic blood pressure, making the main measurement process during cuff decompression described below extremely efficient.

Next, when the constant discharge valve 12 opens, the force 2 pressure decreases from point b toward point 0 at a constant speed (2 to 3 BHg/5ec).

During this period, the CPU 6 monitors the appearance and disappearance of the sound in a more rigorous manner than before. That is, the true sound signal is separated from noise by logical product processing with the pulse synchronization signal m, and the cuff pressure at the time when 1 first appears in the sound is taken as the subject's systolic blood pressure SYS. However, to confirm this, the CPU 6 determines the systolic blood pressure by detecting sounds for at least three beats.

When the systolic blood pressure is determined, the sudden evacuation valve 13 is opened, and the cuff pressure is changed from 0 point to the sudden evacuation target value d point (predicted diastolic blood pressure PREDIA+β).
It decreases rapidly towards . This is because sound detection is actually unnecessary in this section. At the same time, the CPU 6 monitors the cuff pressure detection signal p, and closes the quick discharge valve 13 when the cuff pressure reaches point d.

As a result, the cuff pressure is reduced again by the constant discharge valve 12, and it becomes possible to accurately detect the sound using the same method as described above. If the CPU 6 detects at least one sound during this period, it can confirm that the pressure at the sudden evacuation target value point d exceeds the diastolic blood pressure. Eventually, when the force 2 pressure drops below the subject's diastolic blood pressure, the sound disappears, but in order to confirm this, the CPU 6 confirms that the sound disappears by noticing that there is no sound within the pulse synchronization signal m of at least 2 beats. , the cuff pressure at the time when the last sound km appeared is determined to be the subject's diastolic blood pressure DIA. Immediately after determining the diastolic blood pressure, the rapid drainage valve 13 is opened, the cuff pressure rapidly decreases from point e to point f, and one step is completed.

The process of this embodiment described above can be compared with the conventional process (indicated by a single button in FIG. 2) of continuously monitoring the sound from its appearance to extinction.

As is generally done, the pressure was increased to a uniformly determined g point within the range of 150 to 200 maHH, and then the volume was brought to a constant volume. In contrast, this embodiment automatically detects point b, which is slightly higher than the subject's systolic blood pressure SYS, and automatically determines the optimal pressurization point for entering the constant volume. This has the advantage that systolic blood pressure can be measured immediately. Conventionally, the sound was continuously measured during constant volume movement from point g to point j after pressurization. In contrast, in this embodiment, when the systolic blood pressure reaches the 0 point during constant volume, it is immediately discharged and the measurement is omitted, and then the diastolic blood pressure is determined during constant volume from point d to point e. Then, one step of measurement is completed. ' Now, assuming that both pressurizing points are point b, we will consider the time difference Δt per measurement between the measurement process according to this embodiment and the measurement process according to the conventional method. The conventional measurement process in this case is shown by a two-dot chain line in the figure. Here, if the constant volume velocity of the cuff pressure is both PaxmmHg/sec, there is no difference in the subject's systolic blood pressure SYS and diastolic blood pressure port IA, so the time difference Δt per measurement of the cocoon process is Δt = (5YS-DIA ) /Pi! ! -(T
K2+β/Pex), and it can be seen that this embodiment performs measurement in an extremely short time.

FIGS. 3(a) and 3(b) are diagrams showing details of determining the optimum pressurizing point of this embodiment. In the same figure (a), when the first sound Pk is detected when the cuff pressure increases, the predicted diastolic blood pressure PRED of the subject is calculated using the cuff pressure at that time.
I mentioned earlier that it would be IA. Furthermore, the second sound Pk2
is detected, the upper limit t of the sound generation period can be predicted from this point on, that is, the CPU 6 detects the first period 1. Based on this, it can be predicted that the next sound Pk2 will occur within t=(1±γ)1+ at the latest. This γ is a value determined by a clinical empirical rule by extracting and comparing data on heart rate fluctuations from a large number of subjects, and in this example,
For example, a fixed value of γ = 0.1 to 0.5 is selected, but it may be a value divided into stages according to the scale of tn. In this case, the table shows values of ±O to ±0.5 as γ. It will be prepared.

Even if the subject's sound generation cycle fluctuates greatly over a short period of time due to many years of experience, this can be covered if the above-mentioned γ is an appropriate value. When the sound Pk2 actually occurs, the next KgPk3 will be t at the latest based on the new period t2.
It can be predicted that this will occur within = (1±γ)tz. Of course, in this case, take the average of tl and tl and get KgPk3
Thus, Pk3. may be used to predict the occurrence of Pk3. Pk, and if no sound is generated within the next time t=(1±γ)t3, the air supply valve 11 is immediately closed, and the cuff pressure at this point is assumed to be the optimum pressurization point. This is because the cuff pressure PRESYS corresponding to the sound Pk4 is predicted to be the subject's systolic blood pressure SYS.

Figure (b) shows a state in which only one sound was detected during cuff pressurization. In this case, when the sound Pk is first detected, the cuff pressure at that time is calculated as the predicted diastolic blood pressure P of the subject.
REDIA is not used because the sound near the diastolic blood pressure is relatively weak and is thought to be lost without being detected. In addition, since PREDIA is not determined in this case, the pressure difference for determining the sudden evacuation target value after determining the systolic blood pressure is set to a predetermined value (for example, 40 m+sHg). Based on many years of clinical experience, it has been determined that the pulse pressure amplitude is on average about 40 m+sHg. This is because it has been confirmed. Furthermore, in this case, since the aforementioned time t cannot be determined, the optimum pressurizing point is determined using a predetermined value (for example, 1,65 ec) instead of the actual period t1. The predetermined value of 1.6 sec is assumed to be the maximum cycle when the pulse rate is 38 beats/in.

Furthermore, the safety measure when no sound is detected is to set the predetermined cuff pressure Pa (at point b') as shown in FIGS.
For example, 150 to 200 layer pass 8) is the limit for the rise. The CPU 6 can easily perform this Fd1'# by reading the cuff pressure detection signal P at appropriate times.

FIG. 4 is a timing chart showing a case where blood pressure measurement of a subject is successfully performed in one trial. , most of what is shown in this figure has already been described in the explanation of FIG.

Here, the relationship between the pulse synchronization signal m and the sound signal will be described. As mentioned above, the pulse synchronization signal m captures the expansion and contraction movement of the blood vessels compressed by the cuff, and it is generally known that this signal appears earlier and disappears later than the sound. Only the sound generated within the pulse synchronization signal m during cuff constant volume is considered to be a true sound signal, and is used for the purpose of removing noise mixed in the K sound. Although not adopted in this embodiment, this method may be used to detect sound during cuff original pressure.

Figure 5 is a timing chart showing the case where the subject's blood pressure measurement is performed by one automatic retry. is similar to that shown in FIG. Figure 5 shows that the predicted diastolic blood pressure PREDIA was much lower than the actual diastolic blood pressure DIA, so the sudden drop from 0 points to 5Vi.
Point d' (e.g. PREDIA + l Ora Hg)
When the patient is suddenly discharged to the point where the cuff pressure has already fallen below the diastolic blood pressure DIA. The constant β (selected as 10 s + 11 Hg in the example) used to set the sudden evacuation target value is 1. For example, when the blood pressure fluctuation width (standard deviation SD of DIA) within the measurement time from PREDIA to DIA is used as the standard, 2 SD To cover 3SD, select 6 mmHg, and to cover 3SD, select 110-5H. Now, in the case of Fig. 5, the CPU 6 moves from point d' to e.
No sound is detected even if the pulse synchronization signal m is counted for 2 beats in the constant volume interval up to point '. Therefore, the cuff pressure at this point (point e') is increased by approximately 20 trrmHg, and the cuff is increased until point d'. Increase pressure. Empirically, the cuff pressure at this time is approximately P.
It is shown that the value is REDIA + 20 mmHH. Therefore, if such retrial is repeated three times, the cuff will be pressurized to PREDIA + 40 mrxHg, and the diastolic pressure port IA can be sufficiently covered. It was mentioned earlier that the pulse pressure amplitude is approximately 40 mHg. When the cuff pressure rises to the d" point, the pressure changes to a constant volume again. In the figure, this pressure covers the diastolic blood pressure (IIA). Several sounds are detected within the pulse synchronization signal m.The sounds disappear when the cuff pressure eventually drops below the subject's diastolic blood pressure DIA, but the CPU 6 detects pulse synchronization for at least two beats to confirm this. The disappearance of the sound is confirmed when there is no sound within signal m, and the cuff pressure at the time when the last sound km appears is determined to be the subject's diastolic blood pressure DIA. Immediately after determining the diastolic blood pressure, the sudden evacuation valve is activated. 13 is opened, the cuff pressure rapidly decreases from point e to point f, and one step is completed.

6 to 9 relate to the program control procedure of the apparatus of this embodiment which executes control according to the above-mentioned operating principle, and FIG. 6 is a flowchart showing the control procedure of one step of blood pressure measurement. In step S1, the air supply valve 11 is opened, and in step 5i
In oo, the optimum pressurization control process is executed. The details of the optimum pressurization control process will be described later, but it is a process for determining the optimum pressurization point of the cuff. When returning from this process, the intake valve 11 is closed in step S2, and the constant discharge valve 12 is opened in step S3. During the constant volume after pressurization, a systolic blood pressure determination process is performed in step 5200, and in step S4, the systolic blood pressure is determined. Display. Immediately after the systolic blood pressure is determined, the emergency discharge valve 13 is activated in step S5.
Open the cuff and rapidly reduce the cuff pressure. In step S6, it is determined whether the predicted diastolic blood pressure PREnIA has been determined in the optimum pressurization control process. If the determination is YES, the cuff pressure reaches the sudden evacuation target (PREDIA + 1) in step S7.
0 mmH3), and if the determination is No, proceed to step S8 and wait for the pressure to decrease to an alternative rapid evacuation target value (sudden evacuation start pressure - 40 mmHg). When the target value is reached, step In S9, the quick discharge valve 13 is closed, and the process can proceed to constant volume in that state. Of course, control may also be used to keep the constant discharge valve 12 closed during the sudden discharge described above. In step 510, the retry counter RC is initialized to O. The retry counter RC is a counter that counts the number of retries when the first attempt at measuring the diastolic blood pressure is unsuccessful. During the fixed volume after the sudden evacuation, a diastolic blood pressure determination process is executed in step 5300. The condition for returning from this process is when no sound is detected within the pulse synchronization signal m for two beats. In step Sll, the value of the sound counter KC is checked, and when KC is not O, it indicates that a sound of 1 or more has been detected.
The flow advances to step 512, where the diastolic blood pressure is displayed and one step ends. However, KC is O due to step Sll determination.
If so, a retry is necessary, and the flow proceeds to step 513 to check whether the retry has been performed three times. If the process has been repeated three times, the process advances to step 320 and an error process occurs. However, if the process has not been repeated three times, the process advances to step S14 and the content of the retry counter RC is incremented by 1.

Step S15. In step S16, the constant discharge valve 12 is closed and the air supply valve 11 is opened. In step S17, the cuff pressure reaches the pressurization start pressure +
Waiting for 201 Otori Hg, Step SlB, S19
Then, the air supply valve 11 is closed, the constant discharge valve 12 is opened, and the process returns to step 5300 to execute the diastolic blood pressure determination process.

FIG. 7 is a flowchart showing the optimum pressurization control processing procedure. In step 5101, a series of initialization processes are performed, namely, the sound counter KC is set to 0, the pressure register PR is set to the upper limit Pa of cuff pressurization, and the timer register TR is set to the constant 1.
．． At 8 seconds, the K sound detection flag KF is initialized to O. The sound detection flag KF becomes logic 1 when the sound signal rises, and is reset when the CPU 6 senses this. In step 5102, it is determined whether the cuff pressure detection signal P has reached the pressurization limit hPR (in this case, the upper limit Pa). If not, it is determined in step 5103 whether or not timer t has timed out. The timer is for detecting whether or not there is a next sound within a predetermined time from the previous sound, and is not activated at first, so the flow advances to step 3104 to check the sound counter KC. . KC is O until the first sound Pk is found.
It is. The flow jumps to step 5107 and checks the K sound detection flag KF. If KF is not 1, step 510
Return to step 2 and repeat the above loop until the first sound occurs. If a sound is found in step 5107, proceed to step 5108 and store the value of the turnip pressure detection signal p at that time in the predictive blood pressure memory (PRE memory). This is because it is stored and used later as the predicted diastolic blood pressure PREDIA. In step 5109, KC is incremented by 1. Step 5110
Then, it is determined whether KC is 2 or more. If KC is smaller than 2, it is not possible to calculate the upper limit E of the period at which the next sound will occur, so the process proceeds to step 5112 and the timer is activated.

In step 5102 again, it is checked whether the pressurization limit is reached or not.
If not satisfied, it is checked in step 5103 whether a timeout has occurred. At this point, TR contains a constant of 1.6 seconds, and if there is no next sound by then, it is determined that it has timed out and the process is exited.

To determine the optimal inflation point when only one sound is detected during cuff inflation. If the timeout has not yet occurred, the flow advances to step 5104 to check the KC. If one or more sounds are occurring, always proceed to step 5105,
A process is performed to separate sound from noise. In Step 5105, the timer also determines whether the timer is 300m5 or more, and if the timer is within 300m5 from the sound (with a heart rate of 200m5).
(equivalent to beat/sin or higher), the previous sound signal is ignored using the empirical rule that no sound is generated in the next time. In step 5106, it is checked whether or not the timer t exceeds 1.6 seconds, and the next sound is not generated at a time exceeding 1.6 seconds from the previous sound (corresponding to a heart rate of 38 beats/win or less). Use a rule of thumb to ignore subsequent sound signals. Therefore step 5105
．． Sound is examined only within the range that both satisfy 5106, and if sound is detected in step 5107, step 51
At step 08, the current cuff pressure p is stored in the memory, at step 5109, KC is incremented by +i, and at step 5110, KC is checked. When KC becomes 2 or more, it becomes possible to calculate the upper limit of the period at which the sound should be generated in the first order. The flow advances to step 5111, where (1±γ)L is set in the one-hour register TR. Until now, TR included a constant of 1.8 sec, but from the next point on, a value multiplied by (1±γ) to the previous period t will be used, allowing for even faster and more accurate main measurements tailored to the subject's condition. Optimal pressurization control is performed for this purpose. Step 5
At 112 the timer is started again and at step 510
Return to 2. When the sound eventually disappears, a timeout is detected in step 5103, the process is exited, and the optimal pressure point is determined when two or more sounds are detected during cuff pressure.

FIG. 8 is a flowchart showing the procedure for determining systolic blood pressure. In step 5201, a series of initialization processes are performed, that is, the pulse counter MC is set to 0, the K sound counter is set to O,
The pressure register PR is initialized to the lower limit value Pb of pressure reduction, the pulse detection flag MF is initialized to O, and the sound detection flag is initialized to 0. For example, below the lower limit value Pb, I&? : This is an impossible value for fI blood pressure. The pulse detection flag MF becomes logic 1 when the rising edge of the pulse synchronization signal m is detected, and the CPU 6
This is a flag that is reset when this is sensed. When the cuff pressure exceeds the decompression limit in Stella PS 202, the process advances to step 214 and error handling is performed. However, such a situation rarely occurs in practice, step 5203
Now check the pulse counter MC. Steps 5204-52
The processing in step 06 is the same as that described in steps 5104 to 5106 in FIG. 7, except that the target is the pulse synchronization signal m.

In step 3206, the pulse detection flag MFt is checked, and the above loop is repeated until the first MF is found.When the first MF is found, the sound flag K is checked in step 5207.
Check F. If KF is detected, the cuff pressure P at that time is stored in the memory in step 5208, and step 5209
Increase KC by +1. :! As long as no sound is detected, the process proceeds to step 5210, and the level of the raw pulse synchronization signal m is checked.

repeating sound detection while the signal level is logic 1;
This is to remove noise by detecting only the sound within the pulse synchronization signal m. When the level of the pulse synchronization signal m eventually reaches logic O, the process proceeds to step 5211, where MC is incremented by 1. In step 5212, KC is adjusted, and if KC=3, the systolic blood pressure SIS is determined, and the process exits. If KC is smaller than 3, the timer is activated in step 5213, and the process returns to step 5202. The subsequent processing is the same as that described in FIG. 7, so the explanation will be omitted.

FIG. 9 is a flowchart showing the procedure for determining diastolic blood pressure. In step 5301, a series of initialization processes are performed, and the pressure register PR is initialized to an even lower lower limit value Pc of reduced pressure. The rest is the same as step 5201 in FIG. Further, the processing from step 5302 to step 5307 is the same as the processing from step 5202 to step 5207 in FIG. 8, and the explanation thereof will be omitted.

Now, when the sound flag KF is detected in step 5307, the cuff pressure P at that time is stored in the memory in step 5308, KC is incremented by 1 in step 5309, and step 53
10 to reset the MC. Diastolic blood pressure is at least 1
Since the determination is made based on the fact that only two consecutive beats of MF are detected after KF is detected, the MC is reset after KF is detected. Further, if the level logic O of the pulse synchronization signal m is detected in step 5311 even though no sound is detected in step 3307, the flow is changed to step 53.
Go to step 12 and add 1 to MC.

When this route is passed, a state in which no sound is generated in the pulse synchronization signal m is shown. In step 5313, it is checked whether MC is 2 or not. If MC is 2, the process exits. If MC is smaller than 2, the timer is activated in step 5314, and the process returns to step 5302. The subsequent processing is the 7th
It is similar to that described in FIG.

The entire device of the present application is small and lightweight, and as mentioned above,
By carrying the cylinder on the waist of the subject, even subjects other than those who are bedridden can carry the entire suit without interfering with their normal lives. Therefore, for example, it is possible to measure data for a whole day every 30 minutes without the subject going to a predetermined location. In this case, the timer means built into the CPU or the like described above controls the start of measurement at every predetermined time. At this time, if the first measurement time is at an incorrect time such as OO hours and Oo minutes,
The subsequent data collection time may be set at 00:00 or 00:30, which is a good time. By doing this, it is easier to prepare a system for accepting measurements from test subjects, data from multiple test subjects can be compared on the same time axis, and fluctuation patterns and reproducibility can be easily examined.

[Effects of the Invention] As described above, according to the present invention, after determining the systolic blood pressure, the constant volume measurement process up to the vicinity of the diastolic blood pressure is omitted, so that rapid and accurate blood pressure measurement can be performed, which was previously impossible. High-speed blood pressure measurement that captures short-term blood pressure fluctuations is becoming popular.

Further, according to the present invention, since no pulsation source or noise source such as a diaphragm pump or a piston pump is used as a pressurization source, the cuff pressure can be increased without pulsation (linearly). Therefore, the development and reduction of Korotkoff sounds during cuff pressurization can be accurately detected, and based on this, the diastolic blood pressure can be accurately predicted, and highly reliable extraction can be performed. Moreover, since there is no noise source, it does not cause stress to surrounding patients, and long-term blood pressure monitor patients do not wake up from sleep even if they perform M-monitoring at night, and blood pressure dynamics during sleep can be accurately captured. I can do it.

Further, according to the present invention, since a liquefied gas cylinder is used as a pressurization source, the device can be made smaller and lighter, and since the vaporization capacity is large, it can be used for a long time even when the device is made portable.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an automatic blood pressure monitor according to an embodiment of the present invention, FIG. 2 is a diagram showing a typical step in blood pressure measurement, and FIG.
a) and (b) are diagrams showing the details of how the optimal pressurization point is determined in this example; FIG. 4 is a timing chart showing the case where the blood pressure measurement of the subject is successfully performed in one trial; Fig. 5 is a timing chart showing the case where the blood pressure measurement of the subject is performed by one automatic retry. Fig. 6 is a flowchart showing the procedure for one step of blood pressure measurement. Fig. 7 is the optimal pressurization control processing procedure. Flowchard showing. FIG. 8 is a flowchart showing the procedure for determining systolic blood pressure, and FIG. 9 is a flowchart showing the procedure for determining diastolic blood pressure. Here, 1... Cuff, 2... Microphone, 3... Pipe, 4... Pressure control section, 5... Korotkoff sound detection section, 6... Central processing unit (CPU
), 7...Display section, 8... Recording section. Patent Applicant Copal Takeda Medical Research Institute Co., Ltd. Figure 3 (0) Basis weight □ Figure 3 (b) Examination □ Procedural amendment March 5, 1985 Patent Office Director General 1. Indication of the case Patent Application No. 59-200504 2, Name of the invention Automatic blood pressure measurement method and device 3, Relationship with the case of the person making the amendment Patent applicant: Copal Takeda Medical Research Institute 4, representative
Rihito 1-2 Toranomon, Minato-ku, Tokyo 105
-12 5 Column 6 for detailed explanation of the invention subject to amendment? 11 Positive contents (1) rPk, J on page 19, line 2 of the specification is rPk3
J and I will correct each other. (2) rPk, J on page 19, line 13 of the specification is “Pk
3”.

Claims (5)

[Claims] (1) A setting step in which the Korotkoff sound signal during cuff inflation is monitored and a predetermined value is set, and a step in which the systolic blood pressure is determined based on the Korotkoff sound signal detected during cuff constant rate decompression after the cuff is stopped. An automatic blood pressure measuring method comprising a hypertension determination step and a rapid pressure reduction step of rapidly reducing the cuff pressure to the predetermined value after the systolic blood pressure determination. (2) a pressurizing means for increasing cuff pressure; a first depressurizing means for decreasing cuff pressure at a predetermined rate; and a second decompressing means for decreasing cuff pressure at a faster rate than the predetermined rate; A pressure detection means for detecting and a K for detecting Korotkoff sound.
K sound detection means for outputting a sound signal; setting means for monitoring the K sound signal while the pressurizing means is being energized and setting a predetermined value; and energizing the first pressure reducing means after the pressurization is stopped. systolic blood pressure determining means for determining the systolic blood pressure based on the sound signal detected during the systolic blood pressure; and pressure reduction control means for energizing the second pressure reducing means based on the systolic blood pressure determination to reduce the cuff pressure to the predetermined value. An automatic blood pressure measuring device comprising: (3) When the setting means can predict the diastolic blood pressure value based on the K sound signal, the setting means sets a value obtained by adding the first pressure value to the diastolic blood pressure value as the predetermined value. The automatic blood pressure measuring device according to item 2. (4) A patent characterized in that the setting means monitors the K sound signal and when the diastolic blood pressure value cannot be predicted, sets the predetermined value to a value obtained by subtracting the second pressure value from the cuff pressure at the time of determining the systolic blood pressure. An automatic blood pressure measuring device according to claim 2 or 3. (5) The automatic blood pressure measuring device according to claim 2, wherein the pressurizing means uses a liquefied gas cylinder as a pressure source.