JPH047216B2 - - Google Patents

Description

Detailed Description of the Invention [Technical Field of the Invention] The present invention relates to a cuff pressure control device, and in particular to a cuff pressure control device that maintains a constant pressure gradient during cuff pressurization to enable accurate and rapid blood pressure measurement. This relates to a control device.

[Prior art and its problems] Blood pressure measurement using a cuff requires accurate cuff pressure reading at the onset and disappearance of Korotkoff sounds.
For determining the diastolic blood pressure, it is desirable that the pressure gradient of the cuff be constant (2 to 3 mmHg/sec).
This is because if the gradient is too small, it will be a burden on the subject, and if the gradient is too large, measurement errors will increase.

Conventionally, this requirement has been satisfied with an extremely simple configuration. That is, the pressurizing means simply raises the cuff to a predetermined pressure, and the required constant gradient pressure characteristic of the cuff has been obtained exclusively by opening a slow exhaust valve of a constant diameter. Therefore, blood pressure measurement had to be performed during a slow evacuation step after pressurization, and it took a long time to measure blood pressure.

Moreover, conventional slow exhaust valves have a simple structure and simply have a small diameter hole. Therefore, the pressure gradient during slow evacuation, which should be constant, actually depends on the level of initial pressurization, changes over time in the pressure during slow evacuation, etc., and also depends on the substantial capacity of the cuff. That is, since the initial pressurization must cover at least the subject's systolic blood pressure, its level differs depending on the subject. Even if this point could be solved by fixing the pressure to a certain value within the range of 150 to 200 mmHg, for example, the actual capacity of the cuff varies depending on the arm circumference of the subject around whom the cuff is wrapped. It was not possible to maintain a constant pressure gradient for different subjects. This point also applies to valves whose hole diameter can be adjusted.

Furthermore, conventional cuff relief valves were uncontrolled. Blood pressure measurement using Korotkoff sound recognition is easily affected by noise (artifacts) caused by the movement of the subject, so various noise countermeasures are taken, but even if the recognition unit can identify artifacts during measurement, Since the exhaust cannot be stopped until the problem is cured, blood pressure measurements often result in incorrect or unsuccessful blood pressure measurements.

[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 maintain a constant pressure gradient during cuff pressurization, thereby achieving precise and rapid An object of the present invention is to provide a cuff pressure control device that enables blood pressure measurement.

Another object of the present invention is to provide a cuff pressure control device that can prevent erroneous blood pressure measurements caused by artifacts.

[Summary of the Invention] In order to achieve the above object, the cuff pressure control device of the present invention is a cuff pressure control device that measures blood pressure by adjusting the pressure of the cuff up to the predicted systolic blood pressure and detecting the onset and disappearance of Korotkoff sounds. , a pressurizing means for pressurizing the cuff with air supply, a cuff pressure detection means for detecting cuff pressure, a timer means for counting time, and a constant air supply control means for controlling the cuff with constant air supply for a predetermined time, A cuff pressurization gradient is determined based on the predetermined time and the pressure difference within the cuff that occurs within the predetermined time, in order to maintain the pressurization gradient (increase rate of cuff pressure) occurring within the cuff at a predetermined constant value. a correction coefficient determining means for determining an air supply time correction coefficient, which is a factor, and synchronizing with a predetermined signal in a predicted diastolic blood pressure and a predicted systolic blood pressure pre- and post-region, which are sections where a constant gradient pressurization characteristic is required in the cuff; The gist of the present invention is to include constant gradient pressurization control means for controlling the cuff pressure for the time corrected by the air supply time correction coefficient.

Preferably, the pressurizing means is a motor pump.

In order to achieve the above object, the cuff pressure control device of the present invention is a cuff pressure control device that measures blood pressure by adjusting the pressure of the cuff up to the predicted systolic blood pressure and detecting the onset and disappearance of Korotkoff sounds. a pressurizing means for pressurizing air, a cuff pressure detecting means for detecting cuff pressure, a timer means for counting time, an air supply control means for supplying air to the cuff for a predetermined control time over a plurality of times; Next, air supply control is performed in order to maintain the pressurization gradient (increase rate of cuff pressure) generated within the cuff at a predetermined constant value based on the control time and the pressure difference within the cuff that occurs within the control time. A control time determining means for determining time; and a control time determining means for determining a time; The outline thereof is to have a synchronous control means for executing a control time determining means.

Preferably, the pressurizing means is a motor pump.

[Embodiments of the Invention] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

FIG. 1 is a block diagram of an automatic blood pressure monitor equipped with a cuff pressure control device according to an embodiment. In the figure,
1 is a cuff wrapped around the arm, 2 is a microphone for detecting Korotkoff sounds, and 3 is a pipe connecting the cuff 1 and the blood pressure monitor body for detecting and controlling cuff pressure.

The main body of the blood pressure monitor is roughly divided into five components: 4 is a pressure control section that detects and controls cuff pressure;
5 is a Korotkoff sound detection unit that detects pulse pressure amplitude and Korotkoff sound; 6 is a central processing unit (CPU) that controls the main control of the blood pressure monitor; 7 is a display that displays various operation switches 24 and systolic and diastolic blood pressures. The operating section 8, which consists of parts 22 and the like, is connected to a battery 10 or
This is a power supply section that includes an AC adapter (not shown) either alone or in combination. Further, numeral 9 is a recording unit for recording systolic and diastolic blood pressure, etc., and is connected when performing automatic measurement over a long period of time.

The pressure control unit 4 uses a driver 11 equipped with a constant voltage drive source VR to adjust the cuff pressure to a target constant gradient (for example, 10 mm).
a pressurizing pump 12 for increasing the pressure by Hg/sec);
Solenoid valve 13 for rapidly decompressing the cuff after blood pressure measurement
, a pressure sensor 14 that detects cuff pressure and converts it into an electrical signal, and an A/D converter 15 that converts an analog signal output from the sensor 14 into a digital signal.

In this embodiment, the constant voltage drive source VR of the driver 11 is provided to cope with the drop in battery voltage over time. For example, if the power source of the pressure pump 12 is a DC motor, the pump air supply flow rate is proportional to the motor rotation speed N, and the rotation speed N is proportional to the motor drive voltage V. Therefore, if the battery voltage drops, the cuff 1 cannot be guaranteed. Therefore, for reasons described later, the switch SW is set to S ₂ only when a predetermined air supply flow rate to the cuff 1 is required.
(VR) side to drive the DC motor at a constant voltage. Such a configuration requires 1 battery in the power supply.
It is suitable for portable blood pressure monitors using 0, and is not necessary when using a stabilized power source with an AC adapter. Also,
As the solenoid valve 13, a bidirectional (open/close) self-holding solenoid valve was used. This is to save excitation power and reduce battery burden.

The Korotkoff sound detection unit 5 includes an amplifier 16 that preamplifies the weak sound signal detected by the microphone 2, and a signal corresponding to the Korotkoff sound by extracting each predetermined frequency component from the output of the amplifier 16 and comparing the amplitudes. Then, a K sound filter 17 pulse-forms this signal and outputs a K sound signal K (hereinafter also simply referred to as K sound), which separates the pulse pressure amplitude signal of the blood vessel included in the output of the pressure sensor 14, and calculates the pulse pressure. It consists of a pulse filter 18 that outputs a pulse gate signal MG synchronized with the amplitude signal and a pulse peak detection signal MP. The pulse gate signal MG captures the expansion and contraction movement of the blood vessels compressed by the cuff when the cuff is gradually pressurized, and it is generally known that this signal appears earlier than the K sound and disappears later. ing. In this example, by using the pulse gate signal MG as a gate signal for detecting the K sound, the weak K sound can be accurately detected from the noise, and the artifact state can be eliminated by taking into consideration the pulse generation cycle, etc. It is identified separately from the K sound.

The CPU 6 includes a ROM containing the processing program of this embodiment, a microprocessor that executes the program, a RAM necessary for data processing, a PIO for inputting and outputting processing data, and a driver that drives the solenoid valve 13, etc. It includes circuits, etc., and various functions realized by executing the processing program are shown as blocks in the block of the CPU 6.

Briefly explaining these functional blocks, 19 includes a timer function and controls the blood pressure measurement sequence as time passes; 20 reads the cuff pressure detection signal P output from the A/D converter 15 in a timely manner, and controls the inside of the cuff. pressure control means for controlling the pressurizing pump 12 and the solenoid valve 13 via the driver 11 in order to obtain pressurization and rapid depressurization with a predetermined gradient;
Reference numeral 21 denotes a blood pressure determining means that examines the K sound that appears and disappears within the pulse gate signal MG and determines the systolic blood pressure and diastolic blood pressure of the subject.

2 to 4 relate to the operating principle of the embodiment of the present invention, and FIG. 2 is a diagram showing a typical step of blood pressure measurement in the embodiment. In the figure, when the switch SW of the driver 11 is connected to the _S1 side, the pressure pump 1
2 is driven at maximum speed, and the cuff pressure for subject A increases from point a to point b. At the initial stage, the pressure rises slowly until a certain amount of air accumulates in the cuff, resulting in the characteristics shown in the figure. The cuff pressure Ps at point b is the target setting value for sudden inflation (e.g. 50mmHg or 80mmHg).
Hg). This value varies depending on the subject's diastolic blood pressure DIA, and can be set and input using the operation switch 24 before measurement. Of course, it may be fixed at a value lower than the clinically known statistical diastolic blood pressure value. In any case, in this section, the pressurizing time is shortened by directly driving the pressurizing pump 12 with battery voltage. When the cuff pressure reaches point b, CPU6
The switch SW of the driver 11 is intermittently connected to the _S2 side to keep the pressure gradient of the cuff 1 constant.

One purpose of the constant gradient pressurization control is to maintain the pressurization gradient at a predetermined value of, for example, 10 mmHg/sec or less, and to accurately capture the pressure at the time when the Korotkoff sound appears and disappears. In other words, CPU6 plays the first K sound.
The cuff pressure at the time PKa ₁ was detected was determined to be the subject's diastolic blood pressure DIA, and the last K sound PKan was determined as the subject's diastolic blood pressure DIA.
The cuff pressure at the time of detection is calculated as the systolic blood pressure.
This means that it can be determined to be SYS.

Another purpose of constant gradient pressurization control is to
This is to accommodate the substantial difference in capacitance of the cuffs. That is,
If the arm circumference of the subject is different, the overlap length of the rolled cuff will be different, resulting in a different effective capacity of the cuff. Pressurized dash-dot straight line for subjects A and B
Please refer to the comparison between bh and ei. The figure shows that subject A's arm circumference is relatively short, so the effective capacity of the cuff is small, and the cuff pressure rises relatively rapidly even with the same constant inflow pressure.Also, subject B's arm circumference is Because it is relatively long, the effective capacity of the cuff is large, and the cuff pressure increases relatively slowly even with the same constant inflow pressurization.

Therefore, assuming that the generation cycles of the K sounds for both A and B are the same, the rate of increase in cuff pressure for each K sound generation cycle for both is different, and the larger the rate of increase in cuff pressure, the greater the measurement error. Summer.

Therefore, in this embodiment, the period from when the K sound appears until it disappears during pressurization is given a constant gradient pressure, thereby ensuring accurate correspondence between the generation of the K sound signal obtained during this period and the cuff pressure. , which attempts to quickly and accurately measure blood pressure during the pressurization process.

When the cuff pressure reaches point C (the K sound disappears), the CPU
6 stops the pressurizing pump 12, opens the solenoid valve 13, and rapidly depressurizes the cuff. This is the end of one step of blood pressure measurement according to this embodiment.

FIG. 2 also shows other termination methods.
That is, when the cuff pressure reaches point c, the CPU 6 again connects the switch SW to the _S1 side and rapidly pressurizes the cuff by an additional 60 mmHg. The purpose of rapid pressurization again is to confirm the previous determination of systolic blood pressure. If a K sound is found during this rapid pressurization, the CPU 6 will re-measure the blood pressure.

FIG. 3 is a diagram illustrating the operating principle of the first embodiment in which correction parameters for constant gradient pressurization are determined at the initial stage of the constant gradient pressurization process.

Generally, the cuff pressure gradient characteristic is a function of the cuff pressure P at that point, and can be represented by a basic function f(P). And the basic function f(P) is f(K, P,
ΔP) sec/cc (where K: pump air supply speed, P: pressure value, ΔP: required pressure change amount). The basic function f(P) shows that if the pressurizing pump 12 is driven at a constant speed, when the cuff pressure is low, the inflow of air will be large and the pressurization speed will be fast, and when the cuff pressure is high, the inflow of air will be small. , the pressurization rate also becomes gentler. Therefore, if the switch SW of the driver 11 remains connected to the _S2 side, the ideal linear characteristic of 10 mmHg/sec cannot be obtained. Therefore, in this embodiment, linear correction is performed by time-controlled driving operation of the pressurizing pump 12. That is, the driving time is controlled to be shortened when the cuff pressure is low, and to be lengthened when the cuff pressure is high, according to the basic function f(P). However, this alone does not address substantial differences in cuff capacity. Therefore, a correction parameter a is introduced and the actual pressurizing pump drive time Tdr is determined as Tdr=a·f(P).

Now, the time Tw (for example, 1 sec) from point b, at which the CPU 6 stops the initial rapid pressurization, is the time for the cuff pressure to stabilize, and the cuff pressure after stabilization is indicated by Pa ₁ . At this point, the CPU 6 drives the pressure pump 12 for a certain period of time Tdc. Next, if you read the cuff pressure Pa ₂ after pressurization, the pressurization amount △Pa ₁ is |Pa ₁ −
Pa ₂ | is. On the other hand, suppose that the pressurizing pump 12 was driven for the same time Tdc for subject B as well.
However, since the cuff capacity of B is relatively large, the cuff pressure increases only by △Pb ₁ . That is, there is a relationship between the two, |△Pa ₁ |>|△Pb ₁ | for the same time Tdc. Therefore, the correction parameter a is determined from each pressurization amount ΔP as a=Tdc·f ⁻¹ (ΔP).
The CPU 6 calculates the subsequent pressurizing pump driving time Tdr=Tdc・f ^-1 (ΔP)・f(P); f(P)=(S,
P, 10), and the pressure control means 20 drives the pressurizing pump 12 for Tdr sec every predetermined time (for example, 1 sec) during the remaining pressurizing process up to point c, so that the pressure is substantially 10 mmHg in any case. Achieves constant gradient pressurization characteristics of /sec.

By the way, even without such control, for example, after reading the cuff pressure Pa ₁ after the elapse of time Tw,
Constant gradient pressurization control seems to be easy if the pressurizer pump 12 is driven, the cuff pressure P is monitored, and the pressurizer pump 12 is turned off when the cuff pressure reaches +10 mmHg. However, in reality, the cuff is pressurized in stages over a short period of time (see Figure 5).
It can be said that the above-mentioned control is excellent.

FIG. 4 is a diagram illustrating the operating principle of the second embodiment in which the immediately preceding pressurization amount is constantly monitored during the constant gradient pressurization process to determine the next pressurization pump drive time. Similarly, the time Tw from point b is the cuff pressure stabilization time. If the cuff pressure after stabilization is Pa ₁ , the CPU
6 is a pressurizing pump 12 for a certain period of time Tdc at the beginning.
to drive. If the cuff pressure at the next point in time is _Pa2 , the pressurization amount △ _Pa1 is | _Pa1 − _Pa2 |. Since Tdc is known, CPU 6 calculates the next drive time based on △Pa ₁ .
Find Tdr as Tdr=Tdc・f ^-1 (ΔPa ₁ )・f(Pa ₂ ). That is, if ΔPa ₁ is larger than a value equivalent to 10 mmHg/sec, the next Tdr is shortened, and if ΔPa 1 is smaller, the next Tdr is lengthened. The next driving time Tdr resulting from this is Ta ₁ .
The pressurization amount ΔPa ₂ at that time is smaller than the target value as shown in the figure. Next, the CPU 6 calculates the next driving time Tdr based on △Pa ₂ as Tdr=Ta ₁・f ^-1 (ΔPa ₂ )・f(Pa ₃ ), and drives the pressure pump 12 only for the calculated Ta _2. do. The figure shows the driving time Ta ₂ is actually 10mmHg/sec
The same control is repeated thereafter.

In the embodiments shown in FIGS. 3 and 4, intermittent pressurization control is performed to provide an apparent constant pressurization of 10 mmHg/sec. This intermittent pressurization control cycle (time
After Ta, Tb, and Ta ₂ have stabilized), one cycle is approximately 1 second, and within that, the pressurization time is short, and the cuff pressure constant time is long compared to this. . The reason for doing this is to detect the K sound during a time period when the cuff pressure is constant, to minimize the time unnecessary for the K sound detection, and to ensure the reliability of the K sound detection.

FIG. 5 is a timing chart illustrating the operation of determining the driving start timing of the pressurizing pump in synchronization with the pulse signal. Up to now, the cycle of pressurizing pump drive has been described as 1 sec. However, after the pulse signal and K sound signal appear, the pressurizing pump drive start timing is synchronized with these signals. The figure shows an enlarged view of how the cuff pressure rises rapidly during a short period of time while the pressurizing pump is running. In this way, after synchronization with the pulse signal or K sound signal is achieved, the K sound is waited for in a certain period after each pressurization. In this way, although the generation period of the K sound differs depending on the subject, the desired measurement accuracy can be achieved if, for example, a pressure of 10 mmHg is obtained for every 1 K sound, which is the most efficient method. In the case of a subject with a fast pulse, the pressure is apparently increased at a rate faster than 10 mmHg/sec, but it can be seen that this has no effect on the accuracy of blood pressure measurement. Note that the control shown in the figure generally causes the K sound to occur immediately before the pulse peak signal MP occurs, but depending on the subject, the K sound may occur within a certain period of time before and after the pulse peak signal MP occurs. Pulse gate signal that covers this range
MG is generated, and driving of the pressurizing pump 12 is started in synchronization with the fall of the signal MG.

Incidentally, such pressure pump drive start timing control is applicable to all the embodiments shown in FIGS. 3 to 4.

6 to 7 relate to the program control procedure for executing control according to each of the operating principles described above.
The figure is a flowchart showing the control procedure of the first embodiment. When the power is turned on, input is made to the initial setting process of S (step) 100. In S1, the display section 22 and buzzer 23 are operated for one second to check the functions. In S2, the solenoid valve 13 is opened, and in S3, the cuff pressure fluctuation is set to a predetermined value (for example, 0.2mmHg/960m).
sec) or below. This is to automatically remove residual air within the cuff. In S4, the solenoid valve 13 is closed, and in S5, "0" is displayed, a buzzer sounds to notify that measurement is possible, and a pressurization mark is displayed. In S6, the subject sets his own set value Ps (for example, 50
mmHg, 80mmHg) from the operation switch 24. Default (for example 50mm) if no input is made.
Hg) is used. In S7, the pressurizing pump 12 is directly driven by the battery power supply voltage. In S8, the pressure sensor 14 starts displaying the sampling pressure, allowing the subject to monitor the cuff pressure. Thereafter, the sampling monitor continues until the systolic and diastolic blood pressure values are displayed and held. In S9, the process waits until the cuff pressure P reaches the set value Ps. Set value Ps
When it reaches, the pressure pump 12 is turned off in S10,
In S11, the process waits for the time Tw to elapse. In S12, the cuff pressure P after stabilization is read and stored in the register _P1 . In S13, the pressure pump 12 is driven at a constant voltage. In S14, wait for the predetermined time Tdc to elapse,
After Tdc has passed, the pressurizing pump 12 is turned on in S15.
Turn off. In S16, the cuff pressure P at that time is read and stored in the register _P2 . In S17, the correction parameter a is determined by a=f(P ₁ -P ₂ ).
In S18, the drive time Tdr of the pressure pump 12 is set to Tdr.
=a・f(P). In S19, the pressure pump 12 is driven at a constant voltage, and in S20, the elapse of time Tdr is waited. After Tdr has elapsed, pressurization pump 1 is activated at S21.
2 is turned OFF, and in S22, it is determined whether the blood pressure determining means 21 has determined the diastolic blood pressure DIA and whether or not the DIA display has been held. In S23, whether or not the systolic blood pressure SYS was determined in the same manner, and whether the SYS
Determine whether the display is held. Until the determination in S23 is satisfied, the above-described pressurization is repeated at a rate of, for example, once per second, and when it is satisfied, the electromagnetic valve 13 is opened in S24 to complete one step of blood pressure measurement.

FIG. 7 is a flowchart showing the control procedure of the second embodiment. Initial setting process S when the power is turned on
Execute 100. In S31, pressurize pump 12
OFF, and waits for time Tw to elapse in S32. S3
3 is the driving time control register for the pressurizing pump 12.
Set a predetermined value Tdc to Tdr. In S34, the cuff pressure P after stabilization is set in the pressure register Pn.
In S35, a timer is started, and in S36, driving of the pressurizing pump 12 is started. In S37, the process waits for Tdr (initially Tdc) to elapse, and in S38, the pressure pump 12 is turned off. In S39, the cuff pressure P at this point is set in the pressure register Pn ₊₁ , and in S40, (Pn-Pn ₊₁ ) is stored in the pressure difference register ΔPn. In S41, it is detected whether a timeout has occurred.
At the beginning of the constant gradient pressurization process, the pulse peak signal
Sometimes there is no MP, so a timeout works instead. Unless timed out, the pulse peak signal MP is waited for in S42. When MP is detected, it is delayed by time Td in S43. This is to cover the K sound. In S44, it is checked whether it is an artifact. If it is an artifact, a timer is started in S45 and the process returns to S41. This is because pressurization is not performed during the artifact. Furthermore, once artifacts are eliminated, pressurization progresses, thereby preventing erroneous blood pressure measurements. If it is determined in S44 that it is not an artifact, the pressure pump drive time Tdr is set to Tdr in S46.
Calculate by =f(△Pn)・f(P). In S47, the contents of register Pn are replaced with the contents of register Pn+ ₁ . S48 and S49 are processes for determining the diastolic and systolic blood pressure and checking the display hold state of each blood pressure value. If the determination and display hold have not yet been completed, the process returns to S35 and the next pressurization is executed. If the determination and display are held, the solenoid valve 13 is opened in S50, and one step in blood pressure measurement is completed.

Although each embodiment has been described above, the various characteristic features shown in each embodiment can be combined depending on the purpose of use to realize an optimal cuff pressure control device.

[Effects of the Invention] As described above, according to the present invention, constant air supply is controlled for a predetermined period of time during cuff pressurization, and the pressure gradient generated within the cuff is reduced from the pressure difference within the cuff that occurs within the predetermined period of time. Since the air supply time correction coefficient to be maintained at a predetermined constant value can be determined, the pressure gradient during cuff pressurization can be controlled and maintained at a constant level, making it possible to accurately and quickly measure blood pressure.

Further, according to the present invention, the cuff is inflated for a controlled time, and the pressure gradient generated within the cuff is maintained at a predetermined constant value based on the pressure difference within the cuff that occurs during the controlled time. Since the time can be determined, the pressure gradient during cuff pressurization can be controlled and maintained at a constant level, making it possible to accurately and quickly measure blood pressure.

Further, according to the present invention, since the start timing of pressurization is synchronized with the pulse heart rate signal and the Korotkoff sound signal, it is possible to prevent blood pressure measurement errors due to artifacts.

[Brief explanation of drawings]

Fig. 1 is a block diagram of an automatic blood pressure monitor equipped with a cuff pressure control device according to an embodiment, Fig. 2 is a diagram showing a typical step of blood pressure measurement according to an embodiment, and Fig. 3 is a diagram showing a typical step of blood pressure measurement according to an embodiment. A diagram illustrating the operating principle of the first embodiment in which the correction parameters are determined at the beginning of the constant gradient pressurization step, and FIG. A diagram explaining the operating principle of the second embodiment that determines the time, FIG. 5 is a timing chart explaining the operation of determining the drive start timing of the pressurizing pump in synchronization with a pulse signal, and FIG. 6 is a diagram of the first embodiment. FIG. 7 is a flowchart showing the control procedure of the second embodiment. Here, 1...cuff, 2...mike, 3...pipe,
4...Pressure control section, 5...Korotkoff sound detection section, 6...
Central processing unit (CPU), 7
...Operation unit, 8...Power supply unit, 9...Recording unit, 10...Battery, 11...Driver, 12...Pressure pump, 13
...Solenoid valve, 14...Pressure sensor, 15...A/D converter, 16...Amplifier, 17...K sound filter, 18...
Pulse filter, 19... Control means, 20... Pressure control means, 21... Blood pressure determination means, 22... Display unit, 23...
Buzzer, 24...operation switch.

Claims (1)

[Scope of Claims] 1. A cuff pressure control device that measures blood pressure by adjusting the pressure of the cuff until the predicted systolic blood pressure is reached and detecting the onset and disappearance of Korotkoff sounds, comprising a pressurizing means for pressurizing the cuff with air supply; cuff pressure detection means for detecting cuff pressure; timer means for counting time; constant air supply control means for controlling constant air supply to the cuff for a predetermined time; In order to maintain the pressurization gradient (increase rate of cuff pressure) generated within the cuff at a predetermined constant value based on the pressure difference between a determining means; in the predicted diastolic blood pressure and predicted systolic blood pressure pre- and post-period regions, which are the sections in which a constant gradient pressurization characteristic is required in the cuff, the cuff is synchronized with a predetermined signal, and for a time corrected by the air supply time correction coefficient; A cuff pressure control device comprising constant gradient pressurization control means for controlling cuff pressure. 2. The cuff pressure control device according to claim 1, wherein the pressurizing means is a motor pump. 3. A cuff pressure control device that measures blood pressure by adjusting the pressure of the cuff until the predicted systolic blood pressure is reached and detecting the onset and disappearance of Korotkoff sounds, which includes a pressurizing means for pressurizing the cuff with air supply and a cuff for detecting the cuff pressure. a pressure detection means, a timer means for counting time, an air supply control means for supplying air to the cuff for a predetermined control time over a plurality of times, and a pressure within the cuff generated during the control time and the control time. control time determining means for determining the control time for the next air supply control in order to maintain the pressurization gradient (increase rate of cuff pressure) generated within the cuff at a predetermined constant value based on the difference; The method further includes a synchronization control means for executing the air supply control means and the control time determining means in synchronization with a predetermined signal in a predicted diastolic blood pressure region and a predicted systolic blood pressure region, which are areas where a constant gradient pressurization characteristic is required. Features a cuff pressure control device. 4. The cuff pressure control device according to claim 3, wherein the pressurizing means is a motor pump.