JP4657666B2 - Blood pressure measurement device - Google Patents

Description

  The present invention relates to a blood pressure measurement device, and more particularly to a blood pressure measurement device that measures the blood pressure of the outer ear and its peripheral portion (appropriate location of the outer ear and its peripheral portion) based on a pulse wave signal detected using light absorption and reflection by blood. The present invention relates to level adjustment of a pulse wave signal.

In a conventional blood pressure measurement device (photoelectric volume pulse wave sphygmomanometer) that measures blood pressure based on a pulse wave signal detected using absorption and reflection of light by blood, is the pulse wave signal small for some reason? Alternatively, if the blood pressure is greatly saturated, an appropriate blood pressure measurement cannot be performed. Therefore, an error signal is issued to prompt the change of the mounting position of the light emitting / receiving element to perform the measurement again, or the method disclosed in Patent Document 1 or the like Thus, after adjusting the light level of the light emitting element and the signal level by signal amplification in the light receiving element, etc., pressurization was performed again to measure blood pressure.
Japanese Patent Publication No. 6-18555

  However, if the pulse wave signal is small or highly saturated for some reason, change the appropriate mounting position of the light emitting / receiving element, or set the appropriate signal adjustment value, and then restart. There was annoyance that had to be measured. As a result, the person to be measured required multiple measurements, that is, compression with multiple cuffs, which was a physical burden.

  The present invention has been made in view of the above problems, and in order to enable appropriate blood pressure measurement, it is possible to adjust the signal level so that the signal level of the pulse wave signal is within a predetermined standard range, and at the same time, blood pressure measurement. The present invention provides a blood pressure measurement device and a blood pressure measurement method that make it possible to reduce the physical burden on the user due to the cuff pressure by shortening the time.

In order to solve the above problems, a blood pressure measurement device according to the present invention comprises the following arrangement. That is, in the blood pressure measurement device, a cuff attached to the outer ear and its peripheral portion and compressing the cuff, detection means for detecting a pulse wave signal due to blood in the blood vessel, and a signal level of the pulse wave signal are adjusted. Level adjustment means, and blood pressure measurement control means for measuring blood pressure based on a pulse wave signal detected by the detection means when the cuff is raised to a predetermined pressure or when the cuff is lowered from the predetermined pressure, The blood pressure measurement control means boosts the cuff while measuring the blood pressure during boosting, and then detects the pulse wave signal detected by the detection means in a state where the cuff is pressurized at the predetermined pressure. If the signal level is within the predetermined range, and if it is determined that the signal level is within the predetermined range, the cuff is lowered without measuring the blood pressure at the time of blood pressure reduction. When it is determined that the signal level is not within the predetermined range, the level adjustment unit adjusts the signal level to be within the predetermined range, and then measures the blood pressure during blood pressure reduction. Control the cuff to step down.

  Further features of the present invention will become apparent from the following best mode for carrying out the invention and the accompanying drawings.

  According to the present invention, it is possible to adjust the signal level so that the signal level of the pulse wave signal is within a predetermined standard range in order to enable appropriate blood pressure measurement of the outer ear and its peripheral part. In addition, it is possible to provide a photoelectric volume pulse wave sphygmomanometer that can reduce the physical burden on the user due to the cuff pressure by enabling the blood pressure measurement time to be shortened.

  Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. However, the constituent elements described in this embodiment are merely examples, and are not intended to limit the scope of the present invention only to them.

(First embodiment)
As a first embodiment of the electronic sphygmomanometer according to the present invention, a photoelectric volume pulse wave sphygmomanometer with an appropriate portion of the outer ear and its peripheral part as a measurement site will be described below as an example.

<Device configuration>
FIG. 1 is a block diagram showing the configuration of the photoelectric volume pulse wave sphygmomanometer of the embodiment. In the figure, reference numeral 1 denotes a cuff, which is fixed to the blood pressure measurement site, preferably the tragus, in the outer ear periphery so that the outer ear and blood vessels (arterioles) in the periphery thereof can be compressed. Reference numeral 2 denotes a rubber tube (air tube) which forms a flow path of air into the cuff 1. Reference numeral 3 denotes a pressure pump that feeds pressurized air into the cuff 1. 4 is a rapid discharge valve, which rapidly reduces the pressure in the cuff 1. 5 is a fine exhaust valve that reduces the pressure in the cuff 1 at a constant speed (for example, 2 to 3 mmHg / sec). Reference numeral 6 denotes a pressure sensor, which changes an electrical parameter according to the pressure in the cuff 1. A pressure detection amplifier (AMP) 7 detects an electrical parameter of the pressure sensor 6, converts it into an electrical signal, amplifies it, and outputs an analog cuff pressure signal P.

  Reference numeral 8 denotes a pulse wave sensor installed in the cuff 1, which includes an LED 8a that irradiates light to a pulsating vascular blood flow, and a phototransistor 8b that detects reflected light from the vascular blood flow (FIG. 2). A pulse wave detection amplifier (AMP) 9 amplifies the output signal of the phototransistor 8b and outputs an analog pulse wave signal M. Here, the LED 8a is connected to a light amount control unit 18 that automatically changes the light amount, and the pulse wave detection amplifier 9 includes a gain control unit 19a that automatically changes the gain and a pulse wave detection filter / amplifier 9. A time constant control unit 19b that changes the time constants of the filter amplifiers 91 and 92 described later is connected. An A / D converter (A / D) 10 converts analog signals M and P (not shown) into digital data D (not shown).

  Reference numeral 11 denotes a control unit (CPU) which performs main control of the present photoelectric volume pulse wave sphygmomanometer. The CPU 11 has an adjustment pressure register 11a that stores the adjustment pressure. Details of this control will be described later with reference to the flowcharts of FIGS. Reference numeral 12 denotes a ROM, which stores a program that is executed by the CPU 11 and performs, for example, the control shown in FIGS. A RAM 13 includes a data memory, an image memory, and the like. A liquid crystal display (LCD) 14 displays the contents of the image memory. Reference numeral 16 denotes a keyboard which can be used to set a measurement start command, an adjustment pressure value, and the like by a user operation. A buzzer 15 informs the user that the device has sensed that the key in the keyboard 16 has been pressed, the measurement has been completed, and the like. In this example, the adjustment pressure register 11 a is provided in the CPU 11, but an adjustment pressure storage unit may be provided in the RAM 13.

  FIG. 3 is an external perspective view of the photoelectric volume pulse wave sphygmomanometer of the embodiment. In the figure, reference numeral 17 denotes a sphygmomanometer body, which includes a configuration excluding the cuff 1 and the pulse wave sensor 8 of FIG. Here, the rubber tube 2 includes a signal line (not shown) with the pulse wave sensor 8 and is connected to the cuff 1 and the pulse wave sensor 8 (not shown). The display panel 14 of the LCD uses a dot matrix type display panel, and therefore can display various information (for example, characters, figures, signal waveforms, etc.). Reference numeral 20 denotes a power switch, and the keyboard 16 has a measurement start switch (ST) and a numeric keypad for inputting a cuff pressure value and the like.

<How to attach to measurement site>
In order to use the tragus and its periphery as the measurement site, the measurement unit including the cuff is configured to press the tragus from both sides as shown in FIG.

<Operation of the device>
Next, the operation of the photoelectric volume pulse wave sphygmomanometer according to this embodiment will be described below. FIG. 4 is a flowchart of a measurement processing procedure of the photoelectric volume pulse wave sphygmomanometer according to the first embodiment. When the apparatus is turned on by the power switch 20, a self-initial diagnosis process (not shown) is first performed to initialize the apparatus. Thereafter, the process is started by pressing the measurement start switch ST.

  In step S101, the cuff pressure P is read, and in step S102, it is determined whether or not the residual pressure of the cuff 1 is within a specified value. If the residual pressure exceeds the specified value, “residual pressure error” is displayed on the LCD 14 in step S123. If the residual pressure is within the specified value, a cuff pressurization upper limit value (for example, a value larger than the maximum blood pressure value of 120 to 280 mmHg) is set using the keyboard 16 in step S103, and the light amount and gain are set to predetermined values in step S104. Set to value.

  When the setting of the pressurization value and the light quantity / gain is completed, the quick exhaust valve 4 and the fine exhaust valve 5 are closed in steps S105 and S106. In step S107, driving of the pressure pump 3 is started and pressurization (pressure increase) is started. This is the start of the measurement process during pressurization, and the cuff pressure starts increasing at a constant speed (for example, 2 to 3 mmHg / sec). During this time, data processing by each functional block is performed in step S108, and the measurement of the minimum blood pressure and the maximum blood pressure is performed. When the maximum blood pressure is measured (S109), the pressurizing pump 3 is stopped in step S112. In step S110, it is determined whether or not the cuff pressure is higher than the pressure value U set in S103. If P> U, it is still in the normal measurement range and measurement is continued. On the other hand, when P> U, the cuff pressure is already higher than the set value, so that “measurement error” is displayed on the LCD 14 in step S111. If necessary, detailed information such as “signal abnormality during pressurization” is additionally displayed. In step S114, the light amount and gain are adjusted based on the signal level of the pulse wave signal obtained during pressurization.

  When the adjustment of the light quantity / gain is completed, the fine exhaust valve 5 is opened in step S115. This is the start of the measurement process during pressure reduction (pressure reduction), and the cuff pressure starts to decrease at a constant speed (for example, 2 to 3 mmHg / sec). During this time, data processing by each functional block is performed in step S116, and the systolic blood pressure and the diastolic blood pressure are measured. In step S117, it is determined whether or not a minimum blood pressure value is detected during decompression. If not detected, continue measurement. In step S118, it is determined whether or not the cuff pressure is lower than a predetermined value L (for example, 40 mmHg). If P <L, it is still in the normal measurement range, and the flow returns to step S116. On the other hand, when P <L, the cuff pressure is already lower than the normal measurement range, so “measurement error” is displayed on the LCD 14 in step S119. If necessary, display detailed information such as “signal anomaly during decompression”.

  When the measurement is completed in the determination in step S117, the measurement process is completed in the normal measurement range, and the maximum blood pressure value and the minimum blood pressure value measured on the LCD 14 are displayed in step S120, and the tone signal is displayed to the buzzer 15 in step S121. Send. Preferably, different tone signals are sent after normal termination and abnormal termination. In step S122, the remaining air of the cuff 1 is quickly exhausted and the next measurement start is awaited.

<Blood pressure calculation operation>
A graph (schematic diagram) of a pulse wave signal when using a cuff pressure and a velocity (change amount detection) sensor in the time from the start of measurement during pressurization (step S108) to the end of measurement during depressurization (step S116). It is shown in FIG. The blood pressure measurement is generally performed as follows for the graph of FIG. That is, in the measurement at the time of pressurization, the cuff pressure at the point (a) at which the change in the magnitude of the pulse wave signal has started is set as the minimum blood pressure, and the cuff pressure at the time point (b) when the pulse wave signal disappears is set as the maximum blood pressure. On the other hand, the blood pressure measurement at the time of decompression is opposite to the blood pressure measurement at the time of pressurization, and the cuff pressure at the present time (c) of the pulse wave signal is the maximum blood pressure, and the change in the magnitude of the pulse wave signal is eliminated (d). The cuff pressure is the minimum blood pressure.

<Detailed operation of device light quantity and gain adjustment>
FIG. 5 shows a detailed flowchart of the light amount and gain adjustment shown in step S114 of FIG. 4, and FIG. 7 shows a circuit example for realizing the light amount and gain adjustment.

  First, at the time of light quantity and gain adjustment, the time constants of the pulse wave filter amplifiers 91 and 92 are halved by turning on SW1 to SW2 in FIG. In this state, the carrier level is detected in step S52, and it is checked in step S53 whether the pulse wave carrier is within the standard value (20 to 40% of the full scale of A / D10). If it is equal to or smaller than the standard value, the process proceeds to step S54 to check whether or not the light amount is maximum. If not, the light amount controller 18 is controlled in step S56 to increase the light amount. If the amount of light is maximum, the gain is increased by controlling the feedback of the amplifier 90 in step S55. After the process of step S55 or S56, the process returns to step S52 to repeat the carrier wave check again.

  On the other hand, if the carrier level is greater than or equal to the standard value in step S53, it is checked in step S57 whether or not the gain is minimum. If not, the gain control unit 19a controls the feedback of the amplifier 90 in step S59 to increase the gain. Lower. If it is the minimum, the light amount is decreased in step S58. When the process of step S58 or S59 ends, the process returns to step S52 and the carrier wave level is checked again. If the carrier level is within the standard value in step S53, SW1 to SW2 are opened in step S60, the time constants of the pulse wave filter amplifiers 91 to 92 are restored, and the pulse wave gain is adjusted by the amplifier 93 in step S61. And return.

  In the present embodiment, an example in which reflected light from blood in a blood vessel is detected has been described, but transmitted light may be detected instead.

  As described above, the photoelectric volume pulse wave sphygmomanometer according to the present embodiment makes it possible to adjust the signal level so that the signal level of the pulse wave signal is within a predetermined standard range, and at the same time enables highly accurate measurement, By making it possible to shorten the blood pressure measurement time, it is possible to provide a photoelectric volumetric pulse wave sphygmomanometer that can reduce the physical burden on the user due to the cuff pressure. In addition, since the tragus and its peripheral part are insensitive to pain, there is also an effect that pain due to cuff pressure can be reduced, and this also has an effect that it can be easily applied to continuous measurement of blood pressure. .

(Second Embodiment)
As a second embodiment of the electronic sphygmomanometer according to the present invention, a photoelectric volume pulse sphygmomanometer will be described below as an example. In the present embodiment, the light amount and gain are adjusted based on the pulse wave signal obtained prior to the measurement of blood pressure during pressurization, and high-precision blood pressure measurement is provided only by the measurement during pressurization.
Note that the configuration of the apparatus, the mounting method on the measurement site, the blood pressure calculation operation, and the detailed operation of the apparatus light amount and gain adjustment are the same as those in the first embodiment, and thus description thereof is omitted.

<Operation of the device>
Next, the operation of the photoelectric volume pulse wave sphygmomanometer according to this embodiment will be described below. FIG. 8 is a flowchart of the measurement processing procedure of the photoelectric volume pulse wave sphygmomanometer of the second embodiment. When the apparatus is turned on by the power switch 20, a self-initial diagnosis process (not shown) is first performed to initialize the apparatus. Thereafter, the process is started by pressing the measurement start switch ST.

  In step S201, the cuff pressure P is read, and in step S202, it is determined whether or not the residual pressure of the cuff 1 is within a specified value. If the residual pressure exceeds the specified value, “residual pressure error” is displayed on the LCD 14 in step S222. If the residual pressure is within the specified value, a cuff pressure value (for example, a value larger than the maximum blood pressure value of 120 to 210 mmHg) is set using the keyboard 16 in step S203, and the light amount and gain are set to predetermined values in step S204. Set to.

  When the setting of the pressurization value and the light quantity / gain is completed, the quick exhaust valve 4 and the fine exhaust valve 5 are closed in steps S205 and S206. In step S207, driving of the pressure pump 3 is started and pressurization (pressure increase) is started.

  In step S208, it is determined whether or not the cuff pressure is higher than the pressure value C set in S203. If P> C, pressurization is continued. On the other hand, when P> C, the pressurizing pump 3 is stopped in step S209. In step S210, the sensor 8 is used to acquire a pulse wave signal, and in step S211, the light quantity and gain value are reset to obtain a predetermined signal level. In step S212, driving of the pressure pump 3 is started and pressurization is started again. This is the start of the measurement process during pressurization, and the cuff pressure starts increasing at a constant speed (for example, 2 to 3 mmHg / sec). During this time, data processing by each functional block is performed in step S213, and the minimum blood pressure and the maximum blood pressure are measured. When the maximum blood pressure is measured (S214), the pressurizing pump 3 is stopped in step S217, and the remaining air in the cuff 1 is rapidly exhausted in step S218.

  In step S215, it is determined whether or not the cuff pressure is higher than the pressurization value U set in S203. If P> U, it is still in the normal measurement range and measurement is continued. On the other hand, when P> U, the cuff pressure is already higher than the set value, so “measurement error” is displayed on the LCD 14 in step S216. If necessary, detailed information such as “signal abnormality during pressurization” is additionally displayed.

  When the measurement is completed in step S214, the measurement process is completed in the normal measurement range. In step S219, the highest blood pressure value and the lowest blood pressure value measured are displayed on the LCD 14, and a tone signal is sent to the buzzer 15 in step S220. . Preferably, different tone signals are sent after normal termination and abnormal termination.

  As described above, the photoelectric volume pulse wave sphygmomanometer of the present embodiment allows the signal level to be adjusted so that the signal level of the pulse wave signal is within a predetermined standard range in order to enable appropriate blood pressure measurement. This has the effect of reducing the probability of blood pressure remeasurement during decompression. By making it possible to further shorten the blood pressure measurement time, it is possible to provide a photoelectric volume pulse wave sphygmomanometer that can reduce the physical burden on the user due to the cuff pressure.

(Third embodiment)
As a third embodiment of the electronic sphygmomanometer according to the present invention, a photoelectric volume pulse sphygmomanometer will be described below as an example. As described above, in the first and second embodiments, the irradiation unit that irradiates light to the bloodstream of the blood vessel only on one side of the pair of cuffs having a configuration sandwiching the tragus and / or its peripheral part. (LED 8a) and a light receiving portion (phototransistor 8b) that detects reflected light from the bloodstream.

  On the other hand, in the third embodiment, a light irradiation unit (see FIG. 9: LEDs 8a and 21a) and a light receiving unit that detects reflected light (see FIG. 9) on both the tragus and / or a pair of cuffs sandwiching the periphery thereof. And phototransistors 8b and 21b), which can simultaneously measure blood pressure on the tragus and / or a plurality of parts in the periphery thereof, that is, the back side and front side of the tragus.

  As shown in FIG. 9, the blood pressure measurement device according to the third embodiment has a pulse wave sensor 21 in the other cuff 20 in addition to the device configuration of the first embodiment (see FIG. 1). Yes. The cuff 20 includes an LED 21a that irradiates light to the pulsating blood vessel blood flow, and a phototransistor 21b that detects reflected light from the blood vessel blood flow. A sensor using a different measurement principle (such as a method using a pressure pulse wave) may be used for blood pressure measurement. Since other configurations and operations are the same as those in the first and second embodiments, description thereof will be omitted.

  It is known that the tragus and / or blood vessels (arterioles) in the vicinity thereof are close to blood vessels in the brain, and it is considered that changes in blood pressure originating in the brain can be measured. On the other hand, in addition to blood vessels (arterioles) present in the cartilage portion (mainly tragus) of the ear, an artery (superficial temporal artery) directly connected to the heart is also located in the vicinity of the tragus. Therefore, there is an advantage that blood pressure having different information (that is, blood pressure derived from the brain and blood pressure derived from the heart) can be measured simultaneously with a small device in the periphery of the tragus. The photoelectric volume pulse wave sphygmomanometer of the present embodiment makes it possible to set the signal level of the pulse wave signal so that it falls within a predetermined standard range, and it is possible to measure blood pressure with high accuracy in the outer ear periphery. At the same time, it is possible to provide a photoelectric volume pulse wave sphygmomanometer that makes it possible to reduce the physical burden on the user due to the cuff pressure by enabling the blood pressure measurement time to be shortened.

(Other embodiments)
Although the embodiments of the present invention have been described in detail above, the present invention may be applied to a system constituted by a plurality of devices or may be applied to an apparatus constituted by one device.

  The present invention can also be achieved by supplying a program that realizes the functions of the above-described embodiments directly or remotely to a system or apparatus, and the system or apparatus reads and executes the supplied program code. The Accordingly, the program code itself installed in the computer in order to realize the functional processing of the present invention by the computer is also included in the technical scope of the present invention.

  In this case, the program may be in any form as long as it has a program function, such as an object code, a program executed by an interpreter, or script data supplied to the OS.

  As a recording medium for supplying the program, for example, floppy (registered trademark) disk, hard disk, optical disk, magneto-optical disk, MO, CD-ROM, CD-R, CD-RW, magnetic tape, nonvolatile memory card ROM, DVD (DVD-ROM, DVD-R) and the like.

  As another program supply method, a client computer browser is used to connect to an Internet homepage, and the computer program itself of the present invention or a compressed file including an automatic installation function is downloaded from the homepage to a recording medium such as a hard disk. Can also be supplied. It can also be realized by dividing the program code constituting the program of the present invention into a plurality of files and downloading each file from a different homepage. That is, a WWW server that allows a plurality of users to download a program file for realizing the functional processing of the present invention on a computer is also included in the claims of the present invention.

  In addition, the program of the present invention is encrypted, stored in a storage medium such as a CD-ROM, distributed to users, and key information for decryption is downloaded from a homepage via the Internet to users who have cleared predetermined conditions. It is also possible to execute the encrypted program by using the key information and install the program on a computer.

  In addition to the functions of the above-described embodiments being realized by the computer executing the read program, the OS running on the computer based on the instruction of the program is a part of the actual processing. Alternatively, the functions of the above-described embodiment can be realized by performing all of the processes.

  Furthermore, after the program read from the recording medium is written to a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer, the function expansion board or The CPU or the like provided in the function expansion unit performs part or all of the actual processing, and the functions of the above-described embodiments are realized by the processing.

It is a block diagram of the photoelectric volume pulse wave sphygmomanometer of 1st Embodiment. It is explanatory drawing which showed the sensor operation | movement in the cuff of the photoelectric volume pulse wave sphygmomanometer of 1st Embodiment. It is an external appearance perspective view of the photoelectric volume pulse wave sphygmomanometer of 1st Embodiment. It is a flowchart of the blood pressure measurement operation | movement of the photoelectric volume pulse wave sphygmomanometer of 1st Embodiment. It is a flowchart of signal level adjustment operation | movement of the photoelectric volume pulse wave sphygmomanometer of 1st Embodiment. It is a graph (schematic diagram) of a cuff pressure and a pulse wave signal during measurement with the photoelectric volume pulse wave sphygmomanometer of the first embodiment. It is a circuit diagram of the photoelectric volume pulse wave sphygmomanometer of the first embodiment. It is a flowchart of the blood pressure measurement operation | movement of the photoelectric volume pulse wave sphygmomanometer of 2nd Embodiment. It is a block diagram of the photoelectric volume pulse wave sphygmomanometer of 3rd Embodiment. It is a figure which shows a mode that the cuff was mounted | worn with the tragus and its peripheral part.

Claims (5)

A cuff that is attached to the outer ear and the periphery thereof and presses the cuff;
Detection means for detecting a pulse wave signal due to blood in the blood vessel;
Level adjusting means for adjusting the signal level of the pulse wave signal;
Blood pressure measurement control means for measuring blood pressure based on a pulse wave signal detected by the detection means when the cuff is increased to a predetermined pressure or when the cuff is decreased from the predetermined pressure ;
Equipped with a,
The blood pressure measurement control means includes
After boosting the cuff while measuring the blood pressure during boosting, the signal level of the pulse wave signal detected by the detection means is within a predetermined range when the cuff is pressurized at the predetermined pressure. Determine if there is,
If it is determined that the signal level is within the predetermined range, the cuff is stepped down without measuring blood pressure at the time of stepping down,
When it is determined that the signal level is not within the predetermined range, the level adjustment unit adjusts the signal level to be within the predetermined range, and then measures the cuff while measuring blood pressure during blood pressure reduction. Step down,
The blood pressure measuring device is controlled as follows .   In the measurement of blood pressure at the time of pressurization, the cuff pressure at the time when the amplitude of the pulse wave signal increases is determined as the minimum blood pressure, the cuff pressure at the time when the pulse wave signal disappears is determined as the maximum blood pressure, In the blood pressure measurement, the cuff pressure at the time when the pulse wave signal appears is determined as the maximum blood pressure, and the cuff pressure at the time when the amplitude of the pulse wave signal becomes constant is determined as the minimum blood pressure. The blood pressure measurement device according to claim 1. The blood pressure measuring device according to claim 1 or 2, wherein the outer ear and its peripheral part are tragus . The pulse wave signal detected by the detection means according to any one of claims 1 to 3, wherein the photoelectric pulse wave signal der Turkey obtained by absorption and reflection of light by blood in the blood vessel Blood pressure measuring device. The level adjusting means includes
A light amount adjusting means for adjusting an output light amount from the light emitting element;
Gain setting means for adjusting the signal level from the light receiving element ;
Including
The blood pressure measurement control means, the blood pressure measuring device according to claim 4, characterized in that at least one by the adjustment of the gain setting means and said light amount adjusting means.

Images