JP3041936B2 - Electronic sphygmomanometer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Industrial application field The present invention relates to a vibration-type electronic sphygmomanometer, which rapidly reduces the pressure from the vicinity of the systolic blood pressure, which is unnecessary for blood pressure measurement, to the generation of a maximum pulse wave in a pressure reducing process, The present invention relates to an electronic sphygmomanometer that shortens measurement time.

(B) Conventional technology The vibration-type electronic sphygmomanometer comprises a cuff, a pressure pump for pressurizing the cuff, an exhaust valve for reducing the cuff pressure, a pressure sensor for detecting the cuff pressure, and a microcomputer (MPU). ing.

The MPU detects a pulse wave component from the output signal of the pressure sensor, calculates a pulse wave amplitude value from the pulse wave component, and calculates a systolic blood pressure (SYS) and a diastolic blood pressure value (DIA) from the cuff pressure and the pulse wave amplitude value. ) Is included. In general,
The vibration-type electronic sphygmomanometer employs a threshold method for determining a blood pressure value. At the time of measurement, after the cuff is pressurized to block the artery, the pulse wave amplitude value included in the cuff pressure is detected in the process of decompression. When the pulse wave reduces the cuff pressure at a very slow speed,
Volume change of the artery that occurs when blood begins to flow,
This variation is transmitted to the cuff and detected. The pulse wave amplitude value gradually increases as the cuff pressure decreases, takes a maximum value, and then draws a curve (envelope) indicating a temporary decreasing tendency. Here, the maximum pulse wave amplitude value is detected, and the pulse wave closest to a threshold value (for example, 50% of the maximum pulse wave amplitude value) which is a predetermined ratio of the maximum pulse wave amplitude value in the above-described pulse wave amplitude increasing process. The amplitude value is detected, and the cuff pressure at this time is determined as the systolic blood pressure value. In the pulse wave amplitude decreasing process, a pulse wave amplitude value closest to another threshold value (for example, 70% of the maximum pulse wave amplitude value) which is a predetermined ratio of the maximum pulse wave amplitude value is detected, and the cuff at this time is detected. The pressure is determined as the diastolic blood pressure value.

(C) Problems to be solved by the invention The vibration method electronic sphygmomanometer pressurizes a cuff to a pressurization target value (a pressure value equal to or higher than the systolic blood pressure value) to insulate the artery, and then exhausts the blood at a constant speed (4 mmHg / The cuff pressure and the pulse wave information are obtained in the decompression process according to s), and the blood pressure is determined based on the cuff pressure and the pulse wave information. In this blood pressure measurement method, constant slow exhaustion is continued during measurement, so that measurement takes time. As a result, the subject has to endure prolonged compression by the cuff, and the measurement is painful. Especially in hypertensive patients,
Since the slow evacuation is continued from a state in which a large pressure is applied to the cuff, the measurement time is significantly long, and there are disadvantages such as numbness of the arm or congestion at the artery site.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an electronic sphygmomanometer that solves the above-described problems, requires only a short measurement time, and can reduce pain given to a subject.

(D) Means and action for solving the problem In order to achieve this object, the electronic sphygmomanometer of the present invention has the following configuration.

The electronic sphygmomanometer has a cuff, a pressurizing unit that pressurizes the cuff,
Pressure reducing means for reducing the pressure in the cuff; pressure detecting means for detecting a fluid pressure in the cuff; pulse wave component detecting means for detecting a pulse wave component contained in an output signal of the pressure detecting means; Pulse wave amplitude value calculating means for calculating a pulse wave amplitude value from the pulse wave component detected by the wave component detecting means; and a systolic blood pressure based on an output signal of the pulse wave amplitude value calculating means and an output signal of the pressure detecting means. An electronic sphygmomanometer comprising a blood pressure value determining means for determining a blood pressure value and a diastolic blood pressure value, wherein pulse wave information for detecting pulse wave information of the cuff pressure in a pressurization process of rapidly pressurizing the cuff to a pressurization target value. A detecting means, an estimating means for estimating a cuff pressure at the time of occurrence of a maximum pulse wave and an estimating of a systolic blood pressure based on the detected pulse wave information; From the estimated systolic blood pressure From cuff pressure point obtained by subtracting the value, it is characterized in that a pressure reduction control means for rapid depressurization until cuff pressure point obtained by adding a predetermined value to the cuff pressure at the maximum pulse wave generation.

The electronic sphygmomanometer having such a configuration detects the maximum pulse wave (pulse wave peak point) based on the pulse wave information extracted when the cuff is pressurized, and detects the cuff pressure and systolic blood pressure when the maximum pulse wave is generated. Is estimated. Then, in the cuff evacuation (decompression) process, the pulse wave and the cuff pressure near the estimated systolic blood pressure value are read, and the cuff pressure (true systolic blood pressure) corresponding to a pulse wave that is 50% of the maximum pulse wave is detected. . Further, when the cuff pressure passes a cuff pressure point obtained by subtracting a predetermined value (for example, 15 mmHg) from the estimated systolic blood pressure value, a predetermined value (15 mmHg) is added to the cuff pressure at the time of generation of the maximum pulse wave from this cuff pressure point. The pressure is rapidly reduced to the cuff pressure point. This period is a period after the systolic blood pressure (cuff pressure corresponding to 50% in the rising process of the maximum pulse wave), which is not necessary for blood pressure measurement until reaching the maximum pulse wave. Therefore, the measurement time is reduced by rapidly reducing the pressure in this period. Further, when the cuff pressure is reduced to a cuff pressure point obtained by adding a predetermined value to the cuff pressure at the time of occurrence of the re-pulse wave, the operation returns to the cuff slow-speed exhaust again to extract the maximum pulse wave and to set the minimum blood pressure (maximum pulse wave). Cuff pressure corresponding to 70% in the descending process).

Thus, the cuff depressurization in blood pressure measurement is not performed uniformly at a constant rate of slow decompression (eg, 4 mmHg / s exhaust), but is not required for blood pressure measurement (period from systolic blood pressure to maximum pulse wave). ) By rapidly decompressing
The measurement time can be shortened, and the pain of the subject due to the pressure during the measurement can be eliminated.

(E) Embodiment FIG. 2 is a block diagram showing a specific embodiment of the air system and the measurement circuit of the electronic sphygmomanometer according to the present invention.

A pressurizing pump (pressurizing means) 2, a control valve (exhaust means) 3, and a pressure sensor (pressure detecting means) 4 are connected to the cuff 1 via a tube 1a. Control valve 3
Is controlled by a PWM signal and is completely open from fully closed
Up to analog control by changing the duty of the pulse. As the pressure sensor 4, for example, a diaphragm converter using a strain gauge, a semiconductor pressure conversion element, or the like is used. The pressurizing pump 2 and the control valve 3 are controlled by a CPU (Central Processing Unit) 8 described later. The output signal (analog amount) of the pressure sensor 4 is amplified by the amplifier 5 and converted into a digital value by the A / D converter 7 via the low-pass filter 6. The low-pass filter 6 is for removing pump noise at the time of pressurization, and the cutoff frequency of the filter is set to 10 to 30 Hz in order to faithfully extract a pulse wave during the pressurization process. The CPU 8 takes in the output signal of the pressure sensor 4 converted into a digital value by the A / D converter 7 at a constant period. The output signal of the pressure sensor 4 is passed through an amplifier 5 to a low-pass filter 6, which extracts a pulse wave component appearing on the cuff pressure signal and converts this pulse wave signal (pulse wave component) into a CPU 8 signal. Captures.

The CPU 8 has a function of calculating a pulse wave amplitude value and a function of determining a diastolic blood pressure value and a systolic blood pressure value from the obtained pulse wave amplitude value and cuff pressure value. Further, the CPU 8 has a function of estimating the cuff pressure and systolic blood pressure at the time of generation of the maximum pulse wave based on the pulse wave information obtained in the cuff pressurization process, and storing these in a memory. Further, the CPU 8 subtracts a predetermined value (15 mmHg) from the estimated systolic blood pressure estimated value,
It has a function to rapidly reduce the pressure to a cuff pressure point obtained by adding a predetermined value (15 mmHg) to the cuff pressure when the maximum pulse wave is generated.

The CPU 8 displays a systolic blood pressure value and a diastolic blood pressure value on a display 9.
There is a function to display on

FIGS. 1A and 1B are flowcharts showing specific processing operations of the electronic blood pressure monitor of the embodiment.

Turn on the pressure switch of the sphygmomanometer (“ST” after the step)
1], the pressurizing pump 2 is driven (ST2). At the same time, the control valve 3 is completely closed (ST3), and the cuff 1 is rapidly pressurized. Under this cuff pressurization condition, the cuff pressure is read and a pulse wave is extracted (ST4 and S4).
T5). In ST6, it is determined whether or not the maximum pulse wave has been extracted. As shown in FIG. 3, when the maximum pulse wave (pulse wave peak value) is extracted in the rapid pressurization stage of the cuff 1, the determination in ST6 becomes YES, and the cuff pressure at the time of the generation of the maximum pulse wave in ST7. P _M 'is stored (see FIG. 3). Then, the cuff pressure is continuously read and a pulse wave is extracted (ST8 and ST9). In ST10, it is determined whether the estimation of the systolic blood pressure value has been completed. The estimation of the systolic blood pressure value is estimated as a pressure corresponding to the cuff pressure in 50% of the rising process of the maximum pulse wave. When the systolic blood pressure estimated value Ps '(see FIG. 3) is estimated, the determination in ST10 is YES, and the systolic blood pressure estimated value Ps' is determined.
Is stored in the memory (ST11). Then, when the cuff 1 is pressurized to the pressurization target value, the drive of the pressurization pump 2 is stopped (ST12), and then the cuff 1 is started to decelerate at a very low speed (ST13).
The slow exhaust of the cuff 1 is controlled to a speed of about 4 mmHg / s by a control valve. In this cuff evacuation state,
The cuff pressure is read (ST14). In ST15, it is determined whether or not the current cuff pressure is lower than a pressure (Ps ′ + α) obtained by adding a predetermined value α (15 mmHg) to the estimated systolic blood pressure value. As shown in FIG. 3, if the cuff 1 is depressurized and the cuff pressure becomes equal to or lower than this point, the determination in ST15 becomes YES, and reading of the cuff pressure and extraction of the pulse wave are performed in the low-speed exhaust state ( ST16 and ST17). In ST18, it is determined whether or not the current cuff pressure is lower than a pressure (Ps′−α) obtained by subtracting a predetermined value α (15 mmHg) from the estimated systolic blood pressure value Ps ′. If the cuff 1 is depressurized below this point, the determination in ST18 becomes YES and the cuff 1 is rapidly depressurized (ST19). That is, the approximate systolic blood pressure estimated value P estimated during the pressurization of the cuff 1
Detect the cuff pressure and pulse wave amplitude in the range (± 15mmHg) before and after s', detect the true Ps (pulse wave of 50% of the maximum pulse wave and the cuff pressure corresponding to this pulse wave), and then The operation shifts to the rapid exhaust of the cuff 1.

Then, as shown in FIG. 1 (B), the cuff pressure is read during the rapid depressurization of the cuff 1 (ST20). ST
In 21, the cuff pressure is determined whether it is less than 'pressure obtained by adding a predetermined value alpha (15 mmHg) to (P _M' cuff pressure P _M at the time of the maximum pulse wave generator + alpha). That is, it is determined whether or not the cuff pressure has approached the vicinity where the maximum pulse wave occurs. As shown in FIG. 3, if the pressure of the cuff 1 drops to the point of (P _M '+ α), the determination in ST21 becomes YES, the control valve 3 stops rapid depressurization, and the cuff 1 An exhaust state is set (ST22). Then, the cuff pressure reading and the pulse wave extraction are executed under the cuff evacuation state (ST23 and ST2).
4), the maximum pulse wave A _M is detected (ST25). And this A
A _S (pulse wave amplitude at the time of SYS) is obtained by a predetermined calculation from _M, and the cuff pressure that generated it (higher cuff pressure side than A _M generation)
Is calculated as the systolic blood pressure (ST26). Further, a predetermined calculation is performed from A _M to obtain A _D (pulse wave amplitude at DIA) (ST27). Then, the reading of the cuff pressure and the pulse wave extraction are executed (ST28 and ST29). In ST30, A _D obtained in ST27
It is determined whether or not the cuff pressure P _D at the time of occurrence (see FIG. 3), that is, the diastolic blood pressure is stored, and if the diastolic blood pressure is stored,
When the determination in ST30 is YES and the systolic blood pressure and the diastolic blood pressure are displayed on the display 9 (ST31), the cuff 1 is rapidly depressurized (ST32).

(F) Effects of the Invention In the present invention, as described above, the cuff pressure and the systolic blood pressure at the time of generation of the maximum pulse wave are estimated based on the pulse wave information at the time of cuff pressurization. From the cuff pressure point of the value obtained by subtracting the predetermined value from the estimated value to the cuff pressure point of the value obtained by adding the predetermined value to the cuff pressure at the time of the occurrence of the maximum pulse wave, rapid exhaust was performed. It is possible to rapidly decompress the period from around the peak blood pressure to the generation of the maximum pulse wave.
Therefore, it is possible to reduce the measurement time without wasting measurement, and to perform the measurement without giving the subject a pain due to the prolonged compression. In addition, since the measurement time can be shortened, there is an excellent effect that the object of the invention has been achieved, such as a reduction in the probability of noise such as body motion being mixed and an improvement in the reliability of measurement accuracy.

[Brief description of the drawings]

1 (A) and 1 (B) are flowcharts showing specific processing operations of the electronic sphygmomanometer of the embodiment, and FIG. 2 is a block diagram showing an example of the air system and circuit configuration of the electronic sphygmomanometer of the embodiment. FIG. 3 is an explanatory diagram showing the relationship between cuff pressure and pulse wave amplitude showing the state of blood pressure measurement by the electronic blood pressure monitor of the embodiment. 1: Cuff, 2: Pressurized pump, 3: Control valve, 4: Pressure sensor, 8: CPU.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Masafumi Fukura 17 Science Center Building, Chuodoji Minamicho, Shimogyo-ku, Kyoto, Kyoto Prefecture Omron Life Science Research Institute, Inc. (56) References JP-A-64-32841 (JP, A JP-A-63-194639 (JP, A) JP-A-2-234740 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) A61B 5/022-5/0295

Claims (1)

(57) [Claims] 1. A cuff, a pressurizing means for pressurizing the cuff, a pressure reducing means for reducing a pressure in the cuff, a pressure detecting means for detecting a fluid pressure in the cuff, and an output signal of the pressure detecting means. Pulse wave component detection means for detecting a contained pulse wave component, pulse wave amplitude value calculation means for calculating a pulse wave amplitude value from the pulse wave component detected by the pulse wave component detection means, and pulse wave amplitude value calculation An electronic sphygmomanometer comprising a blood pressure value determining means for determining a systolic blood pressure value and a diastolic blood pressure value based on an output signal of the pressure detecting means and an output signal of the pressure detecting means. In the process, pulse wave information detecting means for detecting pulse wave information of cuff pressure,
Estimating means for estimating the cuff pressure and estimating the systolic blood pressure at the time of occurrence of the maximum pulse wave based on the detected pulse wave information, and estimating the systolic blood pressure estimated by the estimating means in the decompression process of evacuation of the cuff at a low speed. An electronic sphygmomanometer, further comprising a decompression control means for rapidly depressurizing a cuff pressure point obtained by subtracting a predetermined value from a cuff pressure point at which a predetermined value is added to a cuff pressure when a maximum pulse wave is generated.