JP2932486B2 - Electronic sphygmomanometer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Industrial application field The present invention relates to a method of compressing a cuff,
The present invention relates to an electronic sphygmomanometer for determining a systolic blood pressure value.

(B) Conventional technology The electronic sphygmomanometer uses a cuff to compress a measurement site of a subject, and depressurizes or increases the air pressure in the cuff (hereinafter simply referred to as cuff pressure) at a very low speed. Information (pulse wave, Korotkoff sound, etc.) is electrically detected to determine a systolic blood pressure value and a diastolic blood pressure value. In an electronic sphygmomanometer that determines a blood pressure value in the decompression process, the cuff is once pressurized to a pressurization target value that is equal to or higher than the subject's maximum blood pressure value, and decompression is started from there. The target pressurization value is set higher so as to cope with a case where the systolic blood pressure value is high. Therefore, the pressure is increased with an unnecessarily high pressure for a healthy person or a hypotensive patient, which may cause pain or congestion.

In contrast, in an electronic sphygmomanometer that determines a blood pressure value during the pressurization process, if the systolic blood pressure value is determined, the pressurization of the cuff is stopped at that point, and the air in the cuff is quickly exhausted, Release the part to be measured. For this reason, since it does not pressurize with a pressure more than necessary, there is little possibility that a subject may be distressed or cause congestion. Especially in recent years, with the performance improvement of pressurized pumps,
It has become easy to commercialize an electronic sphygmomanometer that measures blood pressure during the pressurization process.

(C) Problems to be Solved by the Invention In an electronic sphygmomanometer that measures blood pressure during the above-described pressurization process, the cuff is pressurized at a very low speed from 0 to the systolic blood pressure value. It is from the lowest blood pressure value to the highest blood pressure value, and it is not necessary to pressurize at a very slow speed from 0 to the lowest blood pressure value. For this reason, in the conventional electronic blood pressure monitor that measures the blood pressure in the pressurization process, the measurement time is lengthened, and there is a possibility that the subject may suffer pain or congestion, and the advantage of the blood pressure measurement in the pressurization process cannot be used.

Therefore, there has been proposed a method in which the measurement time is reduced by rapidly increasing the pressure to a predetermined pressure slightly lower than the minimum blood pressure value, and thereafter increasing the pressure at a very low speed. However, this predetermined pressure must be set lower than the diastolic blood pressure value of any subject, so that the predetermined pressure is set to a low value of 20 to 30 mmHg, and the effect of shortening the measurement time was extremely small.

The present invention has been made in view of the above, and has as its object to provide an electronic sphygmomanometer in which measurement time is reduced.

(D) Means for Solving the Problems In order to solve the above problems, the electronic sphygmomanometer of the present invention comprises:
A cuff, a pressurizing unit that pressurizes air in the cuff at a very low speed or a rapid speed, a rapid exhaust unit that quickly exhausts the air in the cuff, a pressure detecting unit that detects air pressure in the cuff, and a subject. Cardiovascular information detecting means for detecting the cardiovascular information, and blood pressure value determining means for determining a blood pressure value based on the pressure signal of the pressure detecting means and the cardiovascular information signal of the cardiovascular information detecting means. A pulse wave information detecting means for detecting pulse wave information of the subject, and a comparison between the pulse wave information of the pulse wave information detecting means and statistical data of the pulse wave. Pressurizing speed switching means for judging whether or not the air pressure has approached the diastolic blood pressure value of the subject, and switching the pressurizing means from rapid pressurization to very slow pressurization when the air pressure in the cuff has approached the diastolic blood pressure value of the subject; And characterized by comprising Is shall.

(E) Action When blood pressure is measured during the pressurization process, in the initial rapid pressurization process, it is detected that the cuff pressure has approached the diastolic blood pressure value of the subject, and the pressure is switched from the rapid pressurization to the slow speed pressurization. Thus, the measurement time can be effectively reduced. The electronic blood pressure monitor of the present invention
The detection is performed based on a comparison between the subject's pulse wave information and the pulse wave statistical data.

For example, since the pulse wave amplitude value increases from the time when the cuff pressure reaches 0 to the minimum blood pressure, when the pulse wave amplitude value reaches a predetermined value, the pressure is switched from the rapid pressurization to the slow pressurization. Pulse wave amplitude value at the time of diastolic blood pressure varies depending on the subject,
As shown in FIG. 4, the distribution falls within a certain range (1.5 to 5.9 mmHg), and the center of the distribution is biased toward the lower limit. Therefore, if the value is near the lower limit of this distribution (1.5 mmHg),
For most subjects, the pressurization rate can be switched from fast to slow at slightly below the diastolic blood pressure value.

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

In this embodiment, the present invention is applied to an electronic sphygmomanometer for an arm, and FIG. 2 is a block diagram illustrating the configuration of the electronic sphygmomanometer according to the embodiment. Reference numeral 2 denotes a cuff to which a pressurizing pump (pressurizing means) 3, a pressure sensor (pressure detecting means) 4, and a quick exhaust valve (quick exhaust means) 5 are connected. The pressurizing pump 3 includes a DC motor, and the rotation speed of the DC motor is PWM-controlled by a pulse signal from the CPU 6. The pressure sensor 4 uses a system in which the detected pressure is represented by a transmission frequency, and the cuff pressure signal is taken into the CPU 6. Further, the opening and closing of the quick exhaust valve 5 is also controlled by the CPU 6.

The CPU 6 calculates the cuff pressure C from the function of controlling the pressurizing pump 3 and the quick exhaust valve 5 and the cuff pressure signal of the pressure sensor 4,
A function of extracting a pulse wave component from the cuff pressure signal by digital filtering and extracting the amplitude value A, a function of comparing the pulse wave amplitude value A with the switching value α and switching the pressurizing speed, a function of extracting the pulse wave amplitude value A And the cuff pressure C and the systolic blood pressure value (SY
S), and has a function of determining a diastolic blood pressure value (DIA). A pressure switch 8 and a display 7 are connected to the CPU 6,
The display 7 displays a systolic blood pressure value, a diastolic blood pressure value, and the like determined by the CPU 6.

The above-described switching value α is a determination value when the pressurization of the cuff 2 is switched from the rapid pressurization to the rapid pressurization, and adopts the pulse wave amplitude value when the cuff pressure is slightly lower than the diastolic blood pressure value. . Fig. 4 shows the results for healthy subjects and hypertensive patients (total 265).
The frequency distribution of the pulse wave amplitude value when the diastolic blood pressure value is observed is shown. In FIG. 4, the distribution spreads between 1.5 mmHg and 5.9 mmHg, but it is most appropriate if this lower limit is set to the switching value α. In this embodiment, 1.5 mmHg is adopted as the switching value α. I have. Of course, the switching value α is not limited to 1.5 mmHg.

Next, the operation of the electronic blood pressure monitor of this embodiment will be described. First, the cuff 2 is wound around the upper arm of the subject, and the power of the electronic sphygmomanometer is turned on. When the power is turned on, it is determined whether or not the pressure switch 8 is turned on (step (hereinafter referred to as ST) 1; see FIG. 1). If the determination in ST1 is NO, the process waits in ST1, and if YES, the process branches to ST2.

In ST2, the quick exhaust valve 5 is closed. Then, the pressurizing pump 3 starts operating and rapid pressurization is performed. The CPU 6 determines the duty ratio of the pulse signal so that the pressurizing speed of this rapid pressurization is 10 to 15 mmHg / S. In addition, pressurization speed v
₁ is obtained by the following equation, _assuming that the time difference t when the cuff pressures C _n and C _m are generated.

v ₁ = (C _n −C _m ) / t (1) During this rapid pressurization, a cuff pressure (C _i ) signal is taken into the CPU 6 at a predetermined sampling cycle (ST4), and a pulse wave is obtained by digital filtering. extracting (P _i) signal (ST5), further extracts the amplitude values a _n of the pulse wave (P _i) (ST6). ST7
In this way the extracted amplitude value A _n determines whether or not a said switching value α or more. If this determination is YES, S
Branches to T8, if NO, to continue extraction of the pulse wave amplitude value A _n returns to ST4.

In ST8, the CPU 6 lowers the duty ratio of the pulse signal, and controls the pressurizing pump 3 so as to perform the fine pressurization at a speed of 2 to 6 mmHg / S. During this minute pressurization, a blood pressure value determination process is performed (ST9), and it is determined in ST10 whether the systolic blood pressure value and the diastolic blood pressure value have been determined. When the determination in ST10 is NO, the blood pressure value determination process (ST9) is continued, and when the determination is YES, the process branches to ST11.

Blood-pressure determining process (ST10) is the oscillometric method, for example, to extract the maximum value A _max of the pulse wave amplitude value A _n, is 70% of the maximum value A _max with the increase side of the pulse wave amplitude value A _n artery cuff pressure when the cuff pressure at which the wave amplitude was observed to determine a diastolic blood pressure, the pulse wave amplitude value is 60% of the maximum value a _max in decreasing side of the pulse wave amplitude value a _n is extracted Is determined as the systolic blood pressure value. Of course, the method of the blood pressure value determination processing is not limited to this, and the Korotkoff method can also be used.

In ST11, the CPU 6 sets the pulse signal to 0 and sets the pressure pump 3
Is stopped, the quick exhaust valve 5 is opened, the air in the cuff 2 is quickly exhausted, and the upper arm of the subject is released from the compression. Then, the determined minimum blood pressure value and maximum blood pressure value are displayed on the display 7, and the blood pressure measurement ends.

FIG. 3 is a diagram for explaining changes in cuff pressure and pulse wave amplitude value during measurement. FIG. 3 (a) is a case of a healthy person, FIG. 3 (b)
Shows the case of a hypertensive patient. Immediately before the appearance of the diastolic blood pressure, the pressurization is switched from rapid to slow speed in both the healthy person and the hypertensive patient, and the measurement time is effectively shortened. In addition, since the rapid evacuation is performed immediately after the determination of the systolic blood pressure value, the upper arm is not pressed with an unnecessarily high pressure especially in a healthy person.

(G) Effects of the Invention As described above, the electronic sphygmomanometer according to the present invention includes pulse wave information detecting means for detecting pulse wave information of a subject, and pulse wave information and pulse wave statistics of the pulse wave information detecting means. Based on a comparison with the data, it is determined whether or not the air pressure in the cuff has approached the diastolic blood pressure value of the subject, and when the air pressure in the cuff has approached the diastolic blood pressure value of the subject, the pressurizing means is rapidly applied. Since it is characterized by comprising a pressurizing speed switching means for switching from pressure to fine speed pressurizing, hypotensive, hypertensive,
Irrespective of the individual differences among healthy persons, there is an advantage that the measurement time can be effectively reduced for any subject.

[Brief description of the drawings]

FIG. 1 is a flowchart illustrating the operation of an electronic sphygmomanometer according to one embodiment of the present invention, FIG. 2 is a block diagram illustrating the configuration of the electronic sphygmomanometer, FIG. 3 (a) and FIG. Figure (b)
Is a diagram illustrating the relationship between the cuff pressure and the pulse wave amplitude value for a healthy person and a hypertensive patient in the same electronic sphygmomanometer,
FIG. 4 is a diagram illustrating the distribution of pulse wave amplitude values at the time of diastolic blood pressure. 2: Cuff, 3: Pressurized pump, 4: Pressure sensor, 5: Quick exhaust valve,
6: CPU.

────────────────────────────────────────────────── ─── Continuation of the front page (72) Kuniyoshi Takahashi, inventor, Tateishi Life Science Research Institute Co., Ltd. 3-3 Hanazono Nakamikadocho, Ukyo-ku, Kyoto-shi, Kyoto (56) Reference JP-A-59-129051 (JP, A) JP-A-63-43645 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) A61B 5/022

Claims (2)

(57) [Claims] 1. A cuff, pressurizing means for pressurizing air in the cuff at a very low speed or speed, rapid exhaust means for rapidly exhausting air in the cuff, and pressure detection for detecting air pressure in the cuff. Means, cardiovascular information detecting means for detecting cardiovascular information of the subject, and blood pressure value determining means for determining a blood pressure value based on a pressure signal of the pressure detecting means and a cardiovascular information signal of the cardiovascular information detecting means. An electronic sphygmomanometer comprising: a pulse wave information detecting means for detecting pulse wave information of the subject; and a rapid pressurization based on a comparison between the pulse wave information of the pulse wave information detecting means and the statistical data of the pulse wave. It is determined whether the air pressure in the cuff has approached the diastolic blood pressure value of the subject during the cuff, and when the air pressure in the cuff has approached the diastolic blood pressure value of the subject, the pressurizing means is changed from rapid pressurization to rapid pressurization. With pressurizing speed switching means for switching An electronic sphygmomanometer characterized by becoming. 2. The pulse wave information detecting means detects a pulse wave amplitude value as pulse wave information, and when the pulse wave amplitude value exceeds a predetermined value obtained from the statistical data, the pressurizing speed switching means. 2. The electronic sphygmomanometer according to claim 1, wherein the means switches from rapid pressurization to fine pressurization.