JPS6179443A - 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, and in particular, the measurement process from measuring and determining the systolic blood pressure of a subject to the vicinity of the diastolic blood pressure is omitted. The present invention relates to an automatic blood pressure measuring method and device that takes into account blood pressure fluctuations of a subject and makes it possible to reliably measure the diastolic blood pressure by retrying the test.

[Prior art and its problems] The measurement process in conventional non-invasive automatic blood pressure monitors is to first increase the cuff pressure to a set value (150 to 2001 intestinal Hg) and then increase it at a constant rate ( 2-3 FengmuHg/5ee)
In the process of decreasing the cuff pressure, the systolic and diastolic blood pressures were rarely determined by continuous measurements in that area. For this reason, the time required for blood pressure measurement 1 + T will depend on the subject's blood pressure value (pulse pressure) if the cuff pumping speed is constant, and in this section the blood flow is almost stopped, so the state of congested blood continues. This has often resulted 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. Therefore, the present inventor proposes to predict the subject's diastolic blood pressure in advance during cuff inflation, determine the subject's systolic blood pressure in the subsequent constant volume measurement, and then omit the measurement process up to the vicinity of the diastolic blood pressure. However, if the blood pressure of the subject fluctuates between the prediction and the determination of the diastolic blood pressure, the above method may not be sufficiently effective.

In addition, conventional automatic blood pressure monitors use diaphragm pumps, piston pumps, etc. as pressurizing means, and the noise emitted by the pressurizing means every time a measurement is made causes stress not only to the subject but also to the people around them. It became. 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 points, and its purpose is to eliminate the constant volume measurement process up to the vicinity of the diastolic blood pressure after determining the systolic blood pressure, and to The object of the present invention is to propose an automatic blood pressure measurement method and device that can quickly and accurately measure blood pressure, taking into consideration the unavailability of systolic blood pressure determination due to blood pressure fluctuations of subjects.

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] In order to achieve the above object, the automatic blood pressure measurement method of the present invention includes a setting step of monitoring the Korotkoff sound signal during cuff pressurization and setting a predetermined value, and a cuff setting step after cuff pressurization is stopped. a systolic blood pressure determination step of determining systolic blood pressure based on the Korotkoff sound signal detected during rapid decompression;

a sudden pressure reduction step of rapidly reducing the Cub pressure after the systolic blood pressure determination to the predetermined value; a diastolic blood pressure determination step of determining the diastolic blood pressure from the Korotkoff sound signal detected during the cuff constant rate decompression after the sudden pressure reduction; It is determined that the Korotkoff sound signal is not detected in a predetermined period during constant-speed cuff decompression after rapid decompression, and the cuff pressure is increased by a predetermined amount, and the lowest Korotkoff sound signal detected during constant-speed cuff decompression after the said pressurization is detected. The outline of the method is to include a retrial step for determining blood pressure.

Further, in order to achieve the above object, the automatic blood pressure measuring device of the present invention includes a 70-pressure means for increasing the cuff pressure, a first pressure reducing means for decreasing the cuff pressure at a predetermined speed, and a first pressure reducing means for decreasing the cuff pressure at a speed higher than the predetermined speed. a second pressure reducing means for decreasing the pressure at a 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 the signal and setting a predetermined value; a systolic blood pressure determining means for determining the systolic blood pressure based on the sound signal detected during activation of the first pressure reducing means after the stop of pressurization; a pressure reduction control means for energizing the second pressure reduction means to reduce the cuff pressure to the predetermined value based on the systolic blood pressure determination; diastolic blood pressure determination means for determining diastolic blood pressure based on a sound signal; and diastolic blood pressure determining means for determining diastolic blood pressure based on a sound signal; The cuff pressure is increased by a predetermined amount by means of biasing,
The outline of the present invention is to include a retry means for determining the diastolic blood pressure based on the sound signal detected during activation of the first pressure reducing means after the stop of pressurization.

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, the predetermined value is set to a value obtained by subtracting the second pressure value from the cuff pressure at the time of determining the systolic blood pressure. This is one aspect of this.

Preferably, one embodiment 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. The main body, which is a pipe connecting the cafe and the main body for control, is roughly divided into three components.

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 pump filled with compressed air, etc., and a regulator 10 that adjusts the gas pressure output from the pressure source 9 to a constant level. and an air supply valve 11 for pressurizing the cuff, and the cuff pressure is controlled at a constant rate (2 to 3 mmHg/5
ee), a constant release valve 12 for reducing the pressure at a rapid rate, a rapid release valve 13 for rapidly reducing the cuff pressure, a pressure sensor 14 for detecting the cuff pressure and converting it into an electrical signal, and a pressure sensor 14 for detecting the cuff pressure and converting it into an electrical signal. The reason why the design of this embodiment, which consists of an A/D converter 15 for converting an analog signal into a digital signal, does not use a pump as the pressure source 9 is to eliminate any pressure noise.

Furthermore, the reason why this embodiment uses a gas cylinder instead of a pump is that a pulsation-free increase characteristic can be easily obtained when increasing the cuff pressure, and the advantage of linearly increasing the cuff pressure will be clear from the explanation below. Moreover, by preferably using a liquefied gas cylinder, it is possible to obtain the pressure source 9 which is small and lightweight and has an extremely large vaporization capacity. It can be used continuously about 100 times, and the cylinder can be adjusted so as not to put strain on the subject's lower back.

The Korotkoff sound detection unit 5 includes an amplifier 16 that forwards 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 amplitudes to generate a sound corresponding to the 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. a pulse filter 18 that separates the signal, pulse-forms it, and outputs a pulse synchronization signal m.
The 0-group synchronized signal m, which consists of , captures the expansion and contraction movement of the blood vessel compressed by the cuff when the pressure applied to the cuff 1 is gradually decreased, and generally this signal occurs earlier than the sound. It is known to disappear slowly. Therefore, this amplitude signal component is extracted by the pulse filter 18 and used as a gate signal for sound detection, thereby accurately detecting a weak sound from among the noise.

The CPU 6 is a ROM that stores the processing program of this embodiment.
, a microprocessor that executes the program, a RAM necessary for data processing, a PIO for inputting and outputting processed data, a driver circuit that drives the supply/discharge valves 11 to 13, etc., and is a block of the CPU 6. , various functions realized by executing the processing program are shown in blocks. To briefly explain these functional blocks, 19 is a control means that controls the main control of the CPU 6;
0 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 and discharge valves 11 to 13 to obtain a predetermined pressurization and depressurization state in the cuff, and 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.

Figures 2 to 5 relate to the operating principle of the device of this embodiment.
In FIG. 1, which shows a typical step of blood pressure measurement, when the air supply valve 11 opens, the cuff pressure starts to rise quickly and without pulsation from point 8 toward 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 diastolic blood pressure PRED I^ of the subject. Cuff pressure (sound Pk at almost constant intervals as it rises)
2°Pk3...Force is detected. Based on this cycle, the CPU 6 determines the maximum time interval t at which the next sound should appear,
Check if there is a sound within that interval.

Eventually, the sound disappears when the cuff pressure exceeds the subject's systolic blood pressure, 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 cuff pressure decreases from point b toward point 0 at a constant rate (2 to 3 mmHg/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 the noise by logical processing with the pulse synchronization signal m, and the cuff pressure at the time when the first sound appears 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. When the cuff pressure eventually falls below the subject's diastolic blood pressure, the sound disappears, but in order to confirm this, the CPU 6 confirms that the sound has disappeared when there is no sound within the pulse synchronization signal m for at least two beats. , the cuff pressure at the time when @km appears at the end is determined to be the subject's diastolic blood pressure 111A. Immediately after determining the diastolic blood pressure, the second valve 13 is opened,
The cuff pressure rapidly decreases from point e to point f, completing one step.

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

As is generally practiced, the hind leg was ejected by applying pressure to the g point, which is uniformly determined within the range of 150 to 200 mmHH. 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. Furthermore, in the past, the sound was continuously measured during constant volume from point g to one point after pressurization. On the other hand, in this embodiment, when the systolic blood pressure is determined at point C during constant volume, the blood pressure is immediately discharged and the measurement is omitted, and then from point d to e, the lowest appropriate pressure during constant volume in 4. Once this is determined, one step of the measurement is completed.

Now, assuming that the pressurizing points are both point b, we will consider the time difference Δt in one 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 P exm + *) Ig/sec, there is no difference in the subject's systolic blood pressure SYS and diastolic blood pressure DIA, so the time difference Δt per measurement in both processes is w t = ( 5YS-DIA) / Pe1- (
Tk2+β/Pet), 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 how the optimum AO pressure point of this embodiment is determined. In the same figure (a),
When the first sound Pk is detected when the cuff pressure increases, the predicted diastolic blood pressure PRE of the subject is calculated using the cuff pressure at that time.
I mentioned earlier what it means to be a DIA. Furthermore, the second sound P
When k2 is detected, the upper limit of the sound generation period can be predicted from this point on. That is, the CPU 6 can predict that the next sound Pk will occur within t=(1±γ)1+ at the latest based on the first period t1. This γ is a value determined by a clinical empirical rule that is determined by comparing heart rate fluctuation data from a large number of subjects. Although a fixed value is selected, it may be a graded value according to the scale of kn, and in this case, values from 6Q to ±0.5 are prepared as γ in the table.

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 sound Pk3 will be t based on the new period t2.
It can be predicted that this will occur within = (1±γ)tz. Of course, in this case, taking the average of tl and tl, the sound Pk3
may be used to predict the occurrence of Pk3, Pk,
Then, if no sound is generated within the next time t: (1 day 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 frog hypertension SYS.

Figure (b) shows a state in which only one sound was detected during cuff pressurization. In this case, when the first mosquito sound Pk1 is detected, the cuff pressure at that point 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. Also, in this case, since PREDIA is not determined, 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 + * mHg).It has been known for many years that the pulse pressure amplitude is on average about h8 H8. This is because it has been clinically 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 values of 1 and 6 sec are assumed to be the maximum period when the pulse rate is 38 beats/+*in.

Furthermore, when no sound is detected, the safety measure is to set the predetermined cuff pressure Pa (at point b') as shown in FIGS.
For example, the increase limit is set at 150 to 200 mmHg). The CPU 5 can easily perform this control 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 elongation movement of the blood vessel compressed by the cuff, and it is generally known that this signal appears earlier and disappears later than the sound. In this method, only the sound generated within the pulse synchronization signal m during cuff constant volume is determined 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 also be used to detect sound during cuff pressurization.

Figure 5 is a timing chart showing the case where the subject's blood pressure is measured by one diurnal retry. is similar to that shown in FIG. Figure 5 shows that the predicted diastolic blood pressure PRED[A was much lower than the actual diastolic blood pressure DIA, so it suddenly changed from 0 to the target value d.
When the cuff pressure is suddenly discharged to point ' (for example, PREDIA + L O + emHg), this indicates a case where the cuff pressure has already fallen below the diastolic blood pressure DIA. The constant β (10 mHg is selected in the example) used for setting the sudden evacuation target value is based on the blood pressure fluctuation range (standard deviation of DIA 1 sD) within the measurement time from PREII IA to DIA, for example. , 61111HK to cover 2SD, 3
When covering SD, 10m+*Hg will be selected. 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 repeated for 2 beats during the periodic inspection interval up to point d.Therefore, the cuff pressure at this point (point e') is increased to approximately 20 mmHH, and the cuff is increased to point d''. Increase the cuff pressure.Experience shows that the cuff pressure at this time is approximately PRE.
It is shown that the value is DIA + 20 mmHH. Therefore, if such a retrial is repeated three times, the cuff will be pressurized to PFiE[lIA + 40=mHg, which can sufficiently cover the diastolic blood pressure DIA. As mentioned earlier, the pulse pressure amplitude is about 40 mmHg on average.When the pressure rises to the d'' point, the pulse pressure changes to a constant volume again.67 This pressure covers the diastolic blood pressure DIA, so the pulse pressure is Some sounds are detected within the synchronization signal m.The sounds disappear as the cuff pressure eventually drops below the subject's diastolic blood pressure 01A, but the CPU 6 detects a pulse synchronization signal m of at least two beats to confirm this. The disappearance of the sound is confirmed when there is no sound inside, and the cuff pressure at the time when the last K @ kI:O 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 force 2 pressure decreases rapidly from point e to point f, and one process 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 51
At 00, optimal pressurization control processing 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 drain valve 13 is opened in step S5.
Open the cuff and rapidly reduce the cuff pressure. In step S6, it is determined whether the predicted diastolic blood pressure PREDIA has been determined in the optimum pressurization control process. If the determination is YES, the cuff pressure is set to the rapid evacuation target value (PREDIA + l) in step S7.
Os+mHg)! Wait for it to go down, and the judgment is N again.
If o, the process advances to step S8 and waits for the pressure to be reduced to the alternative rapid evacuation target value (sudden evacuation start pressure - 40 taHg).
When the value reaches 4, the quick discharge valve 13 is closed in step S9,
You can move on to definite volume in this state. Of course, the constant discharge valve 12 may be closed during the above-mentioned sudden discharge. In step SlO, the retry counter RCt-0 is initialized. Retry counter RC indicates 1 attempt to measure diastolic blood pressure.
This is a counter that counts the number of retries when the first attempt fails. During the fixed volume after the sudden evacuation, a diastolic blood pressure determination process is executed in step 5300. The conditions for returning from this process are 2
This is a case where no sound is detected within the pulse synchronization signal m corresponding to one beat. In step Sll, the value of the sound counter KC is checked, and when KC is not O, it indicates that one or more sounds have been detected, and the flow proceeds to step 512, where the diastolic blood pressure is displayed and one step is completed. However, if KC is O in the determination at step Sll, a retry is necessary, and the flow advances to step S13 to check whether retry has been performed three times.

If the process has been repeated three times, the process advances to step S20 and an error process occurs. However, if the process has not been repeated three times, the process advances to step 514 and the content of the retry counter RC is incremented by 1.

Step 515. In S16, the constant discharge valve 12 is closed.

Open the air supply valve 11. In step 517, wait until the cuff pressure reaches the pressurization start pressure + 20 mmHH. Step S18
．． In S19, 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 processing is performed, namely, the K sound counter KC is set to O, the pressure register PR is set to the upper limit value 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 pressure limiter) PR (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 there is a next sound within a predetermined time from the previous sound, and is initially not activated, so the flow advances to step 5104 to check the sound counter KC. Sound Pk of the first one, KC is 0 until it bites.
It is. The flow jumps to step 5107 and checks the K sound detection flag KF. If KF is not 1, step 510
2, repeat the above loop until the first sound occurs. If a sound is found in step 5107, proceed to step 3108 and store the value of the cuff pressure detection signal p at that time in the predictive blood pressure memory (PRE memory). ) and later used as the predicted diastolic blood pressure PREDIA. In step 5109, KC is incremented by 1. Step 5llO
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 t of the period at which the next sound will occur, so the process proceeds to step 5112 and the timer is activated.

Again in step 5102, it is determined whether or not there is a pressurization limit.
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, the process always proceeds to step 5105, where processing for separating sounds from noise is performed. That is, in step 5105, it is determined whether or not the evening time is 300 m5 or more.
eat/ll1n or higher), the previous sound signal is ignored using the empirical rule that no sound occurs 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 beyond 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
．． Sounds are checked only within a range that both satisfy 5106, and if a sound is detected in step 5107, step 3
In step 108, the cuff pressure P at that time is stored in the memory, in step 5109, KC is incremented by 1, and in 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 next sound should be generated. The flow advances to step 5111, where (1±γ)L is set in the time register TR. Until now, TR included a constant of 1.6 sec, but from the next point on, a value multiplied by (1±γ) of the previous period will be used, making this measurement even faster and more accurate in accordance with the subject's condition. Optimal pressurization control is performed for this purpose. Step 5
At 112, the timer is started again and Ste.
Return to 02°. When the sound eventually disappears, step 510
3, a timeout is detected, 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 O, the Kf force '7 counter is set to O, the pressure register PR is set to the lower limit value of decompression pb, the pulse detection flag MF is set to O, and the K sound is set to O. The detection flag is initialized to O. The lower limit value Pb is, for example, a value below which systolic blood pressure cannot exist. The pulse detection flag MF becomes logical 1 when the rising edge of the pulse synchronization signal m is detected, and is reset when the CPU 6 senses this.
If the cuff pressure exceeds the decompression limit in S202, the process advances to step 214 to process an error. However, such a situation rarely occurs in practice, and in step 5203 the pulse counter MC is checked. The processing in steps 5204 to 5206 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 5206, the pulse detection flag MF is checked, and the above loop is repeated until the first MF is found. When the first MF is found, the sound flag KF is checked in step 5207.
Find out. If KF is detected, the cuff pressure P at that time is stored in the memory in step 5208, and KC is incremented by 1 in step 5209. Further, while 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. Eventually, when the level of the pulse synchronization signal m becomes logic 0, the process proceeds to step 5211, where MC is incremented by +1. In step 5212, KC is checked, 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 3302 to step 5307 is the same as the processing from step 3202 to step 3207t 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
The MC is reset at 310. Since the diastolic blood pressure is determined by detecting only two consecutive beats of MF after at least one KF is detected, the MC is reset after KF is detected. Also, step 5307
If a level logic 0 of the pulse synchronization signal generator is detected in step 5311 even though no sound has already been detected, the flow proceeds to step 5.
Proceed to 312 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
This is the same as 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 device without interfering with their daily 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 a nine-part time such as OO hours and OO minutes,
It is also possible to set the subsequent data collection time to 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, even if the subject's blood pressure fluctuates during periodic measurements up to the vicinity of the diastolic blood pressure after determining the systolic blood pressure, the cuff can be fixed by efficient retrials. Since the blood pressure automatically covers the diastolic blood pressure, high-speed blood pressure IIi determination can be reliably performed in the actual measurement process.

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, cuff pressurization and cuff decompression can be easily controlled and Korotkoff sounds can be produced.

Disappearance can be detected accurately. Since there is no noise source, there is no stress on surrounding patients, and even if blood pressure is measured at night, long-term blood pressure monitoring will not wake I and Nagisa from sleep, and blood pressure dynamics during sleep. can be captured accurately.

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 drawings]

FIG. 1 is a block diagram showing an automatic blood pressure monitor according to an embodiment of the present invention. Figure 2 shows a typical step in blood pressure measurement, Figure 3 (
a) and (b) are diagrams showing the details of determining the optimal pressurization point of this embodiment, and FIG. 4 is a timing chart showing the case where the blood pressure measurement of the subject is normally performed in one trial. FIG. 5 is a timing chart showing a case where blood pressure measurement of a subject is performed by retrying eye movements once. FIG. 6 is a flowchart showing the control procedure for one step of blood pressure measurement. The seventh section is a flowchart showing @overpressure control processing procedure. FIG. 8 is a flowchart showing the systolic blood pressure determination processing procedure, and FIG. 9 is a flowchart showing the diastolic blood pressure determination processing procedure. Here, 1... cuff, 2... hook, 3... pipe. 4... Pressure control section 5... Korotkoff sound detection section, 6
...Central processing unit) (CPU)
. 7...display section, 8...recording section. Figure 3 (0) Time □ Figure 3 (b) Ginkaku □ Procedural amendment dated March 5, 1985 Patent Office Director General 1, Indication of the case Patent application No. 1983-200505 2, Title of the invention Next to a detailed description of the automatic blood pressure measurement method and device invention

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. a high blood pressure determination step; a rapid depressurization step of rapidly reducing the cuff pressure to the predetermined value after the systolic blood pressure determination; and a diastolic blood pressure determining the diastolic blood pressure from the Korotkoff sound signal detected during constant speed cuff decompression after the rapid pressure reduction. In the determination step, the cuff pressure is increased by a predetermined amount by determining that the Korotkoff sound signal is not detected in a predetermined interval during constant speed cuff decompression after said rapid decompression, and the cuff pressure is detected during constant speed cuff decompression after said pressurization. An automatic blood pressure measurement method characterized by comprising a retry step of determining diastolic blood pressure from a Korotkoff sound signal. (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 K 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. and diastolic blood pressure determining means for determining the diastolic blood pressure based on the K sound signal detected while the first pressure reducing means is energized after the decompression is stopped; and diastolic blood pressure determining means for energizing the first pressure reducing means after the decompression is stopped. cuff pressure is increased by a predetermined amount by energizing the pressurizing means, and the cuff pressure is detected while the first decompressing means is energizing after the pressurization is stopped. Said K
An automatic blood pressure measurement device characterized by comprising a retry means for determining diastolic blood pressure based on a sound signal. (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.