JP2010131247A - Blood pressure measuring apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a blood pressure measuring apparatus based on a volume compensation method, for continuously and highly accurately measuring blood pressure even when adopting four limbs other than fingers as measuring sites. <P>SOLUTION: The blood pressure measuring apparatus 1A includes, an air bag 20, a pressure mechanism, a cuff pressure detecting part, and a control part. The pressure mechanism includes: a pressure block 51 having a pressure surface 51a to pressurize the air bag 20; and an actuator 52 for driving the pressure block 51. The control part includes: a servo control part for continuously adjusting the cuff pressure by controlling the driving of the actuator 52 after allowing the cuff pressure to coincide with initial cuff pressure; and a blood pressure acquisition part for continuously acquiring the blood pressure, based on cuff pressure information detected by the cuff pressure detecting part in a state where the servo control of the cuff pressure is being performed. The air bag 20 is fully covered by the pressure surface 51a in a state where the air bag 20 is pressurized against a region to be measured by the pressure block 51. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a blood pressure measurement device (hereinafter also simply referred to as a sphygmomanometer), and more specifically, a blood pressure capable of continuously measuring blood pressure based on a blood pressure measurement method called a volume compensation method. The present invention relates to a measuring device.

  Blood pressure is a typical index used for the analysis of cardiovascular diseases. The blood pressure is an intra-arterial blood pressure when blood flows in the arterial blood vessel, and changes with time as the heart beats. The blood pressure measurement device is a device for measuring this blood pressure.

  Performing risk analysis based on characteristic blood pressure such as systolic blood pressure (maximum blood pressure) and diastolic blood pressure (minimum blood pressure) is effective in preventing diseases such as stroke, heart failure, and myocardial infarction. . In particular, it is known that early morning hypertension, in which blood pressure rises in the early morning, is related to heart disease, stroke, and the like. Furthermore, among the early morning hypertension, it has been found that a symptom in which blood pressure suddenly rises between 1 hour and 1.5 hours after waking up, called morning surge, has a causal relationship with stroke. Therefore, it can be said that grasping the correlation between time (or lifestyle) and blood pressure is useful for risk analysis of cardiovascular diseases. Therefore, in recent years, it has become necessary to continuously measure blood pressure over a predetermined time.

  Moreover, it is necessary to monitor whether there is a sudden change in the condition of patients undergoing surgery, severely ill patients who need treatment in an ICU (Intensive Care Unit), patients undergoing dialysis, and the like. In order to monitor such a patient's condition, it is necessary to continuously measure blood pressure.

  Further, the blood pressure waveform (pulse wave) for each heartbeat includes information that has a very wide range of use in medicine that is useful for the progression of arteriosclerosis and the diagnosis of cardiac function. For this reason, it has become important to continuously record and analyze changes in blood pressure waveforms.

  One blood pressure measurement method is a blood pressure measurement method called an oscillometric method. When measuring blood pressure based on this oscillometric method, a cuff is wrapped around a measurement site (for example, wrist or upper arm), and the pressure in a fluid bag contained in the wound cuff (hereinafter referred to as cuff pressure). ) Is increased until it becomes higher than the systolic blood pressure, and then the pressure is reduced, and the pulsation generated in the artery is regarded as a change in the cuff pressure in either the pressurization process or the depressurization process. By applying a predetermined algorithm, systolic blood pressure and diastolic blood pressure are determined.

  As another blood pressure measurement method, there is a microphone method. This microphone method uses a microphone to detect blood flow sound (Korotkoff sound) that occurs or disappears depending on the change in blood flow during cuff pressure increase / decrease, thereby reducing systolic blood pressure and diastolic blood pressure. To decide. In this microphone method, a Korotkoff sound is generated when the cuff pressure reaches near systolic blood pressure, and disappears (or becomes weak) when the cuff pressure reaches near diastolic blood pressure. .

  Usually, in a sphygmomanometer that employs a blood pressure measurement method as described above, a pressurizing pump and an exhaust valve are used as a pressure increasing / decreasing mechanism for increasing / decreasing a fluid bag contained in the cuff. The pressurizing pump is a means for increasing the cuff pressure by causing the fluid to flow into the fluid bag, and the exhaust valve is a means for decreasing the cuff pressure by allowing the fluid to flow out from the fluid bag. In addition to this, a sphygmomanometer provided with a pressure increasing / decreasing mechanism including an air cylinder and an actuator for driving the air cylinder has also been proposed (for example, see Japanese Patent Application Laid-Open No. 63-92332 (see Patent Document 1). )).

  However, when these blood pressure measurement methods are employed, characteristic blood pressure such as systolic blood pressure and diastolic blood pressure can be measured, but it is impossible to measure a blood pressure waveform for each heartbeat. . In addition, when the blood pressure measurement method is adopted, it takes about several tens of seconds to measure characteristic blood pressure such as systolic blood pressure and diastolic blood pressure, and these characteristic blood pressures are continuously repeated at short intervals. It is also difficult to measure.

  As a blood pressure measurement method for continuously measuring a blood pressure waveform for each heartbeat, there is a blood pressure measurement method called a direct method. The direct method is a method in which a catheter is inserted into an artery to be measured, and a pressure sensor is connected to the catheter to directly measure a change in intra-arterial pressure. However, in the direct method, since the catheter is inserted into the artery, it is necessary to perform the measurement under the supervision of a doctor, and because it is invasive, it causes mental and physical pain to the patient such as pain and risk of infection. There is a problem that can be performed only in a specific environment such as during or after surgery.

  Therefore, a blood pressure measurement method for continuously measuring a blood pressure waveform for each heartbeat in a non-invasive manner has been developed, and representative examples thereof include a blood pressure measurement method called a tonometry method and a blood pressure measurement method called a volume compensation method. There is.

  The blood pressure measurement method called the tonometry method is a method in which the surface of the body where the artery is present is compressed using a contact-type pressure sensor, and the pressure sensor has a planar feeling when the artery is pressed flat. By using the principle that the pressure surface and the intra-arterial pressure match, the blood pressure that changes from time to time is continuously detected by detecting the pressure received by the pressure-sensitive surface of the pressure sensor while the artery is kept flat. It is to be measured.

  However, even when this tonometry method is adopted, it is actually impossible to compress only the artery, and other biological tissues located on the body surface are simultaneously pressed by the pressure sensor. There is a problem that the detected pressure does not always match the intra-arterial pressure. Further, in order to compress the artery flatly, it is necessary to accurately arrange the pressure sensor on the artery, and handling thereof becomes very complicated. Therefore, the tonometry method is only used in a specific environment such as during or after surgery.

  On the other hand, the volume compensation method compresses an artery from outside the body with a cuff containing a fluid bag, and when the volume per unit length of the pulsating artery is kept constant, the pressure (cuff) is applied to the artery. Pressure) and intra-arterial pressure (that is, blood pressure) are balanced, and the cuff pressure is detected using a pressure sensor while servo-controlling (feedback control) the cuff pressure so that the balanced state is maintained. Thus, the blood pressure which changes every moment is continuously measured. References disclosing sphygmomanometers that employ a blood pressure measurement method called volume compensation method include, for example, Japanese Patent Publication No. 59-5296 (Patent Document 2) and Japanese Patent Publication No. 1-331370 (Patent Document 3). Japanese Utility Model Publication No. 3-2246 (Patent Document 4).

  In the sphygmomanometer disclosed in Patent Documents 2 to 4, a finger is employed as a measurement site, and a configuration in which a fluid bag is mounted so as to cover the finger is employed. In the sphygmomanometer, the point at which the arterial volume fluctuation reaches the maximum amplitude in the process of increasing the cuff pressure, which is the internal pressure of the fluid bag, is detected, and the cuff pressure at that time is the initial cuff for servo control. Then, the cuff pressure is servo-controlled so that the fluctuation of the arterial volume is suppressed, and the blood pressure of the subject is continuously measured based on the cuff pressure information in the state where the servo control is being performed. Therefore, the sphygmomanometer based on the volume compensation method as disclosed in these Patent Documents 2 to 4 is less prone to measurement errors and easier to handle the device than the sphygmomanometer based on the tonometry method. It can be said that it is excellent.

In the sphygmomanometer disclosed in Patent Document 2, when determining the initial cuff pressure, when the cuff pressure is matched with the initial cuff pressure, and when servo control of the cuff pressure is performed, the fluid bag is provided. As a means for changing the cuff pressure by increasing / decreasing pressure, a vibration generator is employed. Further, in the sphygmomanometer disclosed in Patent Document 3, means for changing the cuff pressure by increasing / decreasing the fluid bag when determining the initial cuff pressure and when matching the cuff pressure with the initial cuff pressure, respectively. As a means, a linear pump is employed, and a vibrator is employed as means for changing the cuff pressure by increasing / decreasing the fluid bag when performing servo control of the cuff pressure. Furthermore, in the sphygmomanometer disclosed in Patent Document 4, a linear pump and a vibrator are employed as means for changing the cuff pressure by increasing / decreasing the fluid bag when determining the initial cuff pressure. A linear actuator that drives a plunger is employed as means for changing the cuff pressure by increasing or decreasing the pressure of the fluid bag when the cuff pressure is matched with the initial cuff pressure and when cuff pressure servo control is performed. .
Japanese Unexamined Patent Publication No. 63-92332 Japanese Patent Publication No.59-5296 Japanese Patent Publication No. 1-331370 No. 3-2246

  In the sphygmomanometer based on the volume compensation method described above, the volume of the artery extending through the measurement site is kept constant (the cuff pressure and the intra-arterial pressure are in equilibrium, that is, no load is applied to the artery wall). It is indispensable to realize (state), and the configuration of the servo control mechanism, which is a means for realizing the state, is very important. Here, as described above, in the sphygmomanometer disclosed in Patent Documents 2 to 4, a finger is employed as a measurement site, a fluid bag is attached to cover the finger, and the fluid is used for servo control. Pumps, exhaust valves, actuators, and the like are used as mechanisms for pressurizing and depressurizing the bag.

  However, when a finger is employed as the measurement site, a problem remains in terms of measurement accuracy. This is because the diameter of the artery contained in the finger is very small, and the signal-to-noise ratio (S / N ratio) becomes small, resulting in a decrease in measurement accuracy and the influence of environmental factors such as stress. This is because the artery is easy to receive. Therefore, when developing a sphygmomanometer based on the volume compensation method, from the viewpoint of improving measurement accuracy, the extremities other than fingers such as wrists and upper arms including arteries that are large in diameter and are not easily affected by environmental factors It is preferable to be employed as a part to be measured.

  However, when the limbs other than the fingers such as the wrist and upper arm are used as the measurement site, the external shape of the measurement site itself is larger than when the finger is used as the measurement site. When the fluid bag is configured to cover the part, the volume of the fluid bag is increased, and the above-described pump, exhaust valve, actuator, etc. are used as a mechanism for pressurizing and depressurizing the fluid bag. There arises a problem that the response of the servo control is greatly lowered. When such servo control responsiveness decreases, it becomes difficult to match the cuff pressure to the target value, and the volume of the artery extending through the measurement site is kept constant. It can no longer be realized. Therefore, conventionally, there has been a problem that blood pressure cannot be continuously measured using the volume compensation method when the extremities other than the finger are employed as the measurement site.

  Therefore, the present invention has been made to solve the above-described problems, and blood pressure can be continuously measured with high accuracy even when the extremities other than the fingers are employed as the measurement site. An object of the present invention is to provide a blood pressure measurement device based on a volume compensation method.

  The blood pressure measurement device according to the present invention is capable of measuring the blood pressure of a subject, and includes a fluid bag, a pressing mechanism that presses the fluid bag toward a measurement site, and an internal pressure of the fluid bag. A cuff pressure detecting unit for detecting a certain cuff pressure, an arterial volume detecting unit for detecting the volume of an artery extending through the measurement site, and controlling the driving of the pressing mechanism and continuously acquiring the blood pressure of the subject. And a control unit. The pressing mechanism includes a pressing block having a pressing surface for pressing the fluid bag, and an actuator that drives the pressing block. The control unit includes a cuff pressure initial setting unit that matches the cuff pressure with a predetermined initial cuff pressure, and the arterial volume information detected by the arterial volume detection unit after matching the cuff pressure with the initial cuff pressure. And a servo control unit that continuously adjusts the cuff pressure by controlling the driving of the actuator so that the fluctuation of the arterial volume is suppressed, and a servo control of the cuff pressure by the servo control unit. A blood pressure acquisition unit that continuously acquires the blood pressure of the subject based on the cuff pressure information detected by the cuff pressure detection unit. The fluid bag is completely covered by the pressing surface in a state where the fluid bag is pressed against the measurement site by the pressing block.

  In the blood pressure measurement device according to the present invention, the fluid sealed in the fluid bag is prevented from being discharged to the outside during at least servo control of the cuff pressure by the servo control unit. It is preferably sealed. Here, as a specific method for realizing that the fluid bag is sealed at least while the servo control is being performed, a pressurizing / depressurizing mechanism described later is provided, and the pressurizing / depressurizing mechanism is performed during the servo control. Uses a method of temporarily sealing the fluid bag by releasing the fluid communication between the mechanism and the fluid bag, or a fluid bag in which a predetermined amount of fluid is sealed in the fluid bag in advance without a pressure-increasing / depressing mechanism described later. The method of doing etc. can be considered.

  In the blood pressure measurement device according to the present invention, it is preferable that the cuff pressure initial setting unit adjusts the cuff pressure to the initial cuff pressure by controlling driving of the actuator.

  In the blood pressure measurement device according to the present invention, it is preferable that the pressing mechanism further includes an auxiliary actuator that variably adjusts the relative position of the actuator with respect to the measurement site. Preferably, the cuff pressure initial setting unit controls the driving of the auxiliary actuator so that the cuff pressure matches the initial cuff pressure.

  In the blood pressure measurement device according to the present invention, it is preferable that the blood pressure measurement device further includes a pressure increasing / decreasing mechanism for increasing / decreasing the cuff pressure by allowing fluid to enter and exit the fluid bag. In this case, the cuff pressure initial setting unit includes The cuff pressure is preferably matched to the initial cuff pressure by controlling the driving of the pressure increasing / decreasing mechanism.

  In the blood pressure measurement device according to the present invention, the control unit variably controls the cuff pressure, and the cuff pressure information detected by the cuff pressure detection unit at that time and the arterial volume detection unit It is preferable to further include an initial cuff pressure determining unit that determines the initial cuff pressure based on the detected arterial volume information. In that case, it is preferable that the initial cuff pressure determining unit variably controls the cuff pressure by controlling the driving of any one of the actuator, the auxiliary actuator, and the pressure increasing / decreasing mechanism, Further, it is preferable that the initial cuff pressure determining unit sets the cuff pressure at the time when the change amount of the arterial volume becomes maximum to the initial cuff pressure.

  In the blood pressure measurement device according to the present invention, the control unit variably controls the cuff pressure, and the initial cuff pressure is based on the cuff pressure information detected by the cuff pressure detection unit at that time. May further include an initial cuff pressure determining unit. In that case, it is preferable that the initial cuff pressure determining unit variably controls the cuff pressure by controlling the driving of any one of the actuator, the auxiliary actuator, and the pressure increasing / decreasing mechanism, Further, the initial cuff pressure determining unit sets a cuff pressure having the same value as the diastolic blood pressure calculated based on the cuff pressure information detected by the cuff pressure detecting unit as the initial cuff pressure. Is preferred.

  In the blood pressure measurement device according to the present invention, it is preferable that the pressure increasing / decreasing mechanism includes a pressurizing pump for pressurizing the fluid bag and an exhaust valve for depressurizing the fluid bag. .

  In the blood pressure measurement device according to the present invention, the arterial volume detection unit emits light to the artery, and transmitted light and / or reflected light of the artery irradiated by the light emitting element. It is preferable that a light receiving element for receiving light is included.

  ADVANTAGE OF THE INVENTION According to this invention, even when employ | adopting limbs other than a finger | toe as a to-be-measured site | part, it can be set as the blood pressure measuring device based on the volume compensation method which can measure a blood pressure continuously with high precision. .

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the embodiment described below, a case where the present invention is applied to a so-called wrist type sphygmomanometer in which a wrist is employed as a measurement site will be described as an example.

(Embodiment 1)
1A is a schematic cross-sectional view in the measurement state of the sphygmomanometer according to Embodiment 1 of the present invention, and FIG. 1B is a schematic top view. FIG. 2 is a block diagram showing a hardware configuration of the sphygmomanometer shown in FIG. First, the configuration of the sphygmomanometer according to the present embodiment will be described with reference to FIG. 1A, FIG. 1B, and FIG.

  As shown in FIG. 1A, the sphygmomanometer 1 </ b> A according to the present embodiment includes a mounting table 10 and a support frame 11. The mounting table 10 is a table on which the wrist 200 is mounted, and the support frame 11 is a machine frame disposed on the mounting table 10. The mounting table 10 has a concave portion 10a capable of holding the wrist 200 at a predetermined position on the upper surface thereof, and the concave portion 10a is formed in a shape capable of holding the wrist 200 in an inclined posture. Yes. Specifically, the concave portion 10a has a left-right asymmetric shape in a cross section intersecting with the direction in which the concave portion 10a extends, so that the wrist surface where the radial artery 212 is present faces upward. In this state, the wrist 200 is configured to be held by the recess 10a. A pressing mechanism, which will be described later, is assembled at a predetermined upper position of the support frame 11.

  As shown in FIG. 1A, FIG. 1B, and FIG. 2, the sphygmomanometer 1A includes an air bag 20, a pressure sensor 31, an oscillation circuit 34, a light emitting element in addition to the mounting table 10 and the support frame 11 described above. 41, a light receiving element 42, a light emitting element drive circuit 43, a received light amount detection circuit 44, an actuator 52, an actuator drive circuit 53, an encoder 54, a control unit 100, a display unit 110, a memory unit 120, an operation unit 130, and a power supply 140. Yes.

  The air bag 20 is a fluid bag attached to the wrist 200 as a site to be measured, and is for compressing the radial artery 212 that is present on the wrist 200 by being inflated. The air bag 20 has a space inside, and a predetermined amount of air is sealed in advance in the space. In sphygmomanometer 1A according to the present embodiment, an air bag is adopted as a fluid bag. However, a fluid bag in which other fluid (for example, gas, liquid, gel, etc. other than air) is enclosed is used. Of course, it is also possible to use.

  The control unit 100 is constituted by, for example, a CPU (Central Processor Unit), and is a part that centrally controls each part of the sphygmomanometer 1A and performs various arithmetic processes. The display unit 110 is configured by, for example, an LCD (Liquid Crystal Display) or the like, and is a part for displaying blood pressure data, an operation guide, or the like as a measurement result. The memory unit 120 includes a ROM (Read-Only Memory) and a RAM (Random-Access Memory), and stores various data such as a program for causing the control unit 100 to execute a predetermined operation and a measurement result. It is a part.

  The operation unit 130 includes, for example, various switches, and is a means for accepting an operation by a subject or the like and inputting a command from the outside to the control unit 100 or the power supply 140. The operation unit 130 calls, for example, a power switch 131 that switches on / off the power supply 140, a measurement switch 132 that receives a measurement start instruction, a stop switch 133 that receives a measurement stop instruction, and various data stored in the memory unit 120. The memory switch 134 for displaying on the display unit 110 is included. The power source 140 is a part for supplying power to the control unit 100.

  The pressure sensor 31 corresponds to a cuff pressure detection unit that detects a cuff pressure that is an internal pressure of the air bladder 20, and outputs an output signal corresponding to the internal pressure of the air bladder 20 toward the oscillation circuit 34. As the pressure sensor 31, for example, a capacitance type sensor can be used. The oscillation circuit 34 generates a signal having an oscillation frequency corresponding to the signal input from the pressure sensor 31 and outputs the generated signal to the control unit 100.

  The light emitting element 41 irradiates light toward the radial artery 212 in a portion extending through the wrist 200, and is configured by an LED (Light Emitting Diode), for example. The light receiving element 42 receives light transmitted from the radial artery 212 and / or reflected light of the light irradiated by the light emitting element 41, and is configured by a PD (Photo Diode), for example. The light emitting element 41 and the light receiving element 42 correspond to an arterial volume detection unit that detects the volume of the radial artery 212 in the wrist 200.

  In order to detect the arterial volume with high accuracy, it is preferable to use near infrared light that easily passes through living tissue as detection light. The light emitting element 41 and the light receiving element 42 emit and receive near infrared light. Each possible one is preferably used. More specifically, near infrared light having a wavelength of about 940 nm is particularly preferably used as detection light emitted from the light emitting element 41 and received by the light receiving element 42. The detection light is not limited to the near-infrared light near 940 nm, and light near a wavelength of 450 nm, light near a wavelength of 1100 nm, or the like can be used.

  The light emitting element driving circuit 43 is a circuit for causing the light emitting element 41 to emit light based on a control signal from the control unit 100, and causes the light emitting element 41 to emit light by applying a predetermined amount of current to the light emitting element 41. is there. As a current applied to the light emitting element 41, for example, a direct current of about 50 mA is used. As the light emitting element driving circuit 43, a circuit that causes the light emitting element 41 to periodically emit light by supplying a pulse current to the light emitting element 41 with a predetermined duty is preferably used. When the light emitting element 41 is caused to emit light in this manner, it is possible to suppress the power applied per unit time to the light emitting element 41 and to prevent the temperature of the light emitting element 41 from rising. The driving frequency of the light emitting element 41 is set to a frequency (for example, about 3 kHz) sufficiently higher than the frequency component (approximately 30 Hz) included in the fluctuation of the arterial volume to be detected, thereby detecting the arterial volume more precisely. It becomes possible to do.

  The received light amount detection circuit 44 is a circuit for generating a voltage signal corresponding to the received light amount based on the signal input from the light receiving element 42 and outputting the voltage signal to the control unit 100. Since the amount of light detected by the light receiving element 42 changes in proportion to the arterial volume, the voltage signal generated by the received light amount detection circuit 44 also changes in proportion to the arterial volume. Is regarded as a voltage value fluctuation. Here, the received light amount detection circuit 44 includes processing circuits such as an analog filter circuit, a rectifier circuit, an amplifier circuit, an A / D (Analog / Digital) conversion circuit, and the like. Output as a converted voltage signal.

  The actuator 52 corresponds to a pressing mechanism that presses the air bag 20 attached to the wrist 200 toward the wrist 200, and has a drive shaft 52a that is driven in the axial direction. The actuator drive circuit 53 drives the actuator 52 based on the control signal from the control unit 100. The encoder 54 detects the position of the drive shaft 52 a of the actuator 52 and outputs the detected position information to the control unit 100.

  As shown in FIGS. 1 (A) and 1 (B), the body of the actuator 52 is fixed to the support frame 11 so that the drive shaft 52a extends toward the wrist 200 mounted on the mounting table 10. Yes. A pressing block 51 is fixed to the tip of the drive shaft 52a of the actuator 52, and the pressing block 51 is moved in the direction of arrow A in the figure by driving the actuator 52. The pressing block 51 has a pressing surface 51 a at the lower end located on the wrist 200 side, and the pressing surface 51 a has a curved shape along the surface of the wrist 200. The width of the pressing surface 51a in the direction along the circumferential direction of the wrist 200 is preferably set to a size that covers the radial artery 212 present on the wrist 200 and the living tissue in the vicinity thereof.

  The air bag 20 described above is adhered to the pressing surface 51 a of the pressing block 51. The light emitting element 41 and the light receiving element 42 described above are disposed inside the air bag 20. Here, the light emitting element 41 and the light receiving element 42 are arranged to be spaced apart from each other so as to sandwich the wrist surface of the portion located immediately above the radial artery 212 in a state where the wrist 200 is placed on the placing table 10. Is preferred.

  With the above configuration, the air bag 20 can be pressed toward the wrist surface where the radial artery 212 is exposed by driving the actuator 52. At that time, by controlling the operation of the actuator 52, the pressing force applied to the wrist 200 when the air bag 20 is pressed can be appropriately adjusted. Accordingly, the blood pressure can be continuously measured by controlling the operation of the actuator 52 so that this pressing force is balanced with the internal pressure of the radial artery 212 and servo-controlling the cuff pressure.

  Here, in the sphygmomanometer 1A according to the present embodiment, the air bag 20 has the pressing surface 51a of the pressing block 51 in the measurement state (that is, the state in which the air bag 20 is pressed against the wrist 200 by the pressing block 51). It is supposed to be completely covered by. Specifically, as shown in FIG. 1B, when the air bag 20 is viewed in plan along the pressing direction of the air bag 20, the outer shape of the air bag 20 is more than the outer shape of the pressing surface 51 a of the pressing block 51. The press surface 51a has a sufficient margin so that the air bag 20 does not protrude from the press surface 51a even when the air bag 20 is pressed toward the wrist 200 by the press block 51. Thus, the position of the air bag 20 and the pressing surface 51a is adjusted.

  By configuring in this way, the air bag 20 is completely covered with the pressing surface 51a of the pressing block 51 in the measurement state, so that the air bag 20 protrudes from the pressing surface 51a and the pressing force to the wrist 200 is reduced. It is possible to set the ratio of increase / decrease of the cuff pressure with respect to the movement amount of the drive shaft 52a of the actuator 52, and to servo-control the cuff pressure with higher responsiveness than before. Become.

  In the following, the reason why cuff pressure servo control becomes impossible when an open-loop pressure increasing / decreasing mechanism (a pressure increasing / decreasing mechanism using a pressure pump and an exhaust valve) used in a conventional blood pressure monitor is adopted. The reason why the cuff pressure servo control becomes possible when the pressure increasing / decreasing mechanism such as the sphygmomanometer 1A in the present embodiment is employed will be described with reference to FIGS.

  In general, it is known that the difference between the highest blood pressure and the lowest blood pressure (pulse pressure) reaches about 150 mmHg in a large case. In addition, it is known that the maximum blood pressure of a patient suffering from hypertension is approximately over 200 mmHg. In addition, it is known that the frequency component included in the pulse wave for each beat is about 13 Hz on average at rest and about 25 Hz on average during exercise. Taking the above conditions into consideration, the air flow rate for causing the cuff pressure to follow the blood pressure change for each beat is calculated as follows.

  FIG. 14 is a diagram showing a general pulse wave shape, and FIG. 15 is a diagram showing an example of cuff compliance in the case where a wrist is adopted as a measurement site. As shown in FIG. 14, the frequency component contained in the pulse wave becomes maximum at the rising portion of the pulse wave (portion indicated by reference numeral 400 in the figure), and is maximum 150 mmHg in about 0.04 seconds in a hypertensive patient. Rise to the extent. Therefore, in order to realize the equilibrium state between the intra-arterial pressure and the cuff pressure by servo-controlling the cuff pressure, it is necessary to pressurize the cuff pressure up to 150 mmHg for 0.04 seconds. As shown in FIG. 15, the cuff compliance is approximately 0.15 ml / mmHg when the cuff pressure is within a range of 90 mmHg to 240 mmHg, for example. In order to increase the cuff pressure by 150 mmHg within this range, 0.15 An air flow rate of [ml / mmHg] × 150 [mmHg] = 22.5 [ml] is required. In order to realize this in 0.04 seconds, an air flow rate of at least 22.5 [ml] /0.04 [seconds] = 33.75 [liter / minute] is required.

  Realization of the above-described air flow rate is almost impossible with an open loop pressurizing and depressurizing mechanism using a pressurizing pump and an exhaust valve. Specifically, assuming pressurization control using an existing pressurization pump, a large-capacity pump is required as a pressurization pump, and the sphygmomanometer itself becomes larger than the practical range. become. In addition, when assuming pressure reduction control with an existing exhaust valve, there is a concern that the responsiveness may be significantly reduced by increasing the flow rate, and the minimum control amount will be greatly increased. It is almost impossible to realize the above-mentioned cuff compliance.

  Further, when the above-described open-loop type pressure increasing / decreasing mechanism is employed, the following problems also occur. FIG. 16 is a diagram showing a flow rate-pressure characteristic when an open loop pressure increasing / decreasing mechanism is used, pressurizing an air bag with a constant driving voltage of a pressurizing pump, and a constant driving voltage of an exhaust valve. It is a figure which shows the flow volume-pressure characteristic at the time of depressurizing an air bag.

  As shown in FIG. 16, in the open-loop system pressure increasing / decreasing mechanism, it can be seen that the air flow rate decreases as the pressure applied to the pressurizing pump and the exhaust valve increases during pressurization. That is, when the pressurizing pump is driven at a constant voltage, it can be seen that the discharge amount of the pressurizing pump decreases as the cuff pressure as the control target increases. On the other hand, during decompression, it can be seen that the higher the pressure applied to the pressurization pump and the exhaust valve, the higher the air flow rate. That is, it can be seen that when the exhaust valve is driven at a constant voltage, the exhaust amount of the exhaust valve increases as the cuff pressure to be controlled increases. It can also be understood from FIG. 16 that this flow rate-pressure specification is non-linear. Therefore, in light of the above-described cuff compliance viewpoint, it can be seen that the controllable pressure range is limited by the open-loop pressure increasing / decreasing mechanism, making it difficult to measure blood pressure with high accuracy.

  On the other hand, when a closed loop pressure increasing / decreasing mechanism such as the sphygmomanometer 1A in the present embodiment is adopted, the above-described problem can be solved. That is, in the sphygmomanometer 1A in the present embodiment, a pressing block 51 having a pressing surface 51a larger than the outer shape of the air bag 20 is attached to the drive shaft 52a of the actuator 52, and the air bag 20 is pressed by the pressing block 51. This makes it possible to servo-control the cuff pressure with good responsiveness even when a wrist is used as the part to be measured, and to measure blood pressure continuously with high accuracy. .

  FIG. 3 is a block diagram showing a functional block configuration of the sphygmomanometer according to the present embodiment. Next, with reference to this FIG. 3, the structure of the functional block of the blood pressure monitor in this Embodiment is demonstrated.

  As shown in FIG. 3, the control unit 100 continuously measures an initial cuff pressure determining unit 102 that determines an initial cuff pressure, a cuff pressure initial setting unit 104 that matches the cuff pressure with the initial cuff pressure, and blood pressure continuously. Therefore, a servo control unit 106 that servo-controls the cuff pressure and a blood pressure acquisition unit 108 that continuously acquires blood pressure are included. In FIG. 3, only the functional blocks that directly exchange signals with the initial cuff pressure determination unit 102, the cuff pressure initial setting unit 104, the servo control unit 106, and the blood pressure acquisition unit 108 are illustrated. ing.

  The initial cuff pressure determining unit 102 uses the actuator 52 to variably control the cuff pressure, and uses the cuff pressure information detected by using the pressure sensor 31 at that time, and the light emitting element 41 and the light receiving element 42. The initial cuff pressure is set based on the arterial volume information detected in step (1). Specifically, the initial cuff pressure determination unit 102 gives a command to drive the actuator 52 to the actuator drive circuit 53, and based on this, the actuator 52 gradually presses the air bag 20 toward the wrist 200, The pressurization is continued until the cuff pressure reaches a predetermined value (for example, 200 mmHg). At that time, the initial cuff pressure determination unit 102 gives a command to drive the light emitting element 41 to the light emitting element drive circuit 43, detects the cuff pressure based on the signal input from the oscillation circuit 34, and receives the received light amount. An arterial volume signal is detected based on the signal input from 44.

  Here, the initial cuff pressure determination unit 102 calculates a volume change signal indicating a change (amplitude change) in the arterial volume for each beat based on the detected arterial volume signal. Then, the initial cuff pressure determining unit 102 compares the volume change signal acquired at that time with the volume change signal already recorded in the memory unit 120, and only when it is determined that the change is larger. The calculated volume change signal and the cuff pressure detected at that time are overwritten and saved in the memory unit 120. Thus, the initial cuff pressure determining unit 102 finally determines the cuff pressure recorded in the memory unit 120 as the initial cuff pressure after the pressurization of the air bladder 20 by the actuator 52 is completed. The initial cuff pressure determination unit 102 outputs the determined initial cuff pressure to the cuff pressure initial setting unit 104.

  The cuff pressure initial setting unit 104 uses the actuator 52 to match the cuff pressure with the initial cuff pressure after receiving the input of the initial cuff pressure. Specifically, the cuff pressure initial setting unit 104 receives an input of the determined initial cuff pressure from the initial cuff pressure determination unit 102, gives a command to drive the actuator 52 to the actuator drive circuit 53, and based on this The actuator 52 gradually releases the pressure of the air bag 20 toward the wrist 200, detects the cuff pressure based on the signal input from the oscillation circuit 34, and when the cuff pressure matches the initial cuff pressure. The drive of the actuator 52 is stopped. After matching the cuff pressure with the target value, the cuff pressure initial setting unit 104 outputs a signal indicating that the initial setting of the cuff pressure has been completed to the servo control unit 106.

  After the cuff pressure matches the initial cuff pressure, the servo control unit 106 controls the actuator 52 so that the fluctuation of the arterial volume is suppressed based on the arterial volume information detected by using the light emitting element 41 and the light receiving element 42. Servo-control the cuff pressure continuously by controlling the drive. Specifically, the servo control unit 106 receives a signal indicating that the initial setting of the cuff pressure is completed from the cuff pressure initial setting unit 104, and drives the light emitting element 41 to drive the light emitting element drive circuit 43. A command is given, an arterial volume signal is detected based on a signal input from the received light amount detection circuit 44, and a volume change signal is calculated based on this. Then, the servo control unit 106 keeps the arterial volume constant at all times (that is, the calculated volume change signal has a predetermined threshold value (for example, the volume change signal calculated in the initial cuff pressure determination step). The pressing force of the air bag 20 against the wrist 200 is adjusted by giving a command for driving the actuator 52 to the actuator driving circuit 53 so that the pressure is less than a predetermined ratio with respect to the maximum value). When the servo control of the cuff pressure is started, the servo control unit 106 outputs a signal indicating that the servo control of the cuff pressure is started to the blood pressure acquisition unit 108, and the calculated volume change signal is determined in advance. Whether the blood pressure is equal to or less than the threshold value (that is, whether the arterial volume is kept constant) is output to the blood pressure acquisition unit 108.

  The blood pressure acquisition unit 108 continuously acquires the blood pressure of the subject based on the cuff pressure information detected by using the pressure sensor 31 in a state where the servo control of the cuff pressure is performed by the servo control unit 106. Specifically, the blood pressure acquisition unit 108 receives a signal indicating that the servo control is started from the servo control unit 106 and generates cuff pressure information based on the signal input from the oscillation circuit 34. In parallel with the generation of the cuff pressure information, the blood pressure acquisition unit 108 receives a signal indicating whether or not the volume change signal calculated from the servo control unit 106 is equal to or less than the predetermined threshold value, and calculates the calculated volume. The cuff pressure when the change signal is equal to or less than the threshold value is determined as the blood pressure, and stored in the memory unit 120 as time series data.

  The operation of each functional block included in the control unit 100 may be configured to be executed by executing software stored in the memory unit 120, or any of these functional blocks may be configured. Alternatively, all may be configured to be realized as independent hardware. Further, any or all of the above-described functional blocks not included in the control unit 100 may be configured to be realized by executing software stored in the memory unit 120.

  FIG. 4 is a flowchart showing blood pressure measurement processing of the sphygmomanometer in the present embodiment. The process shown in FIG. 4 is realized by the control unit 100 reading and executing a program stored in the memory unit 120 in advance.

  As shown in FIG. 4, the control unit 100 first determines whether or not the power switch 131 has been pressed (step S1). If it is determined that power switch 131 has been pressed (YES in step S1), the process proceeds to step S2.

  In step S2, the control unit 100 performs an initialization process. Specifically, a predetermined area of the memory unit 120 is initialized, the air in the air bag 20 is exhausted, and the pressure sensor 31 is corrected.

  When the initialization is completed, the control unit 100 determines whether or not the measurement switch 132 has been pressed (step S3). If it is determined that measurement switch 132 has been pressed (YES in step S3), the process proceeds to step S4.

  In step S4, the initial cuff pressure determination unit 102 of the control unit 100 executes an initial cuff pressure determination process. The initial cuff pressure determination process will be described in detail with reference to FIGS. 5 and 6. FIG. 5 is a flowchart showing the initial cuff pressure determining process, and FIG. 6 is a schematic diagram for explaining the initial cuff pressure determining process. 6A shows the cuff pressure Pc along the time axis, and FIG. 6B shows the arterial volume signal Si along the time axis. FIG. Indicates the volume change signal Sii along the time axis.

  As shown in FIG. 5, the initial cuff pressure determination unit 102 initializes the maximum value and the cuff pressure of the volume change signal Sii stored in a predetermined area of the memory unit 120 (step S101). In the following processing, the maximum value of the volume change signal Sii is updated as needed, and the value until the final value is finally determined is referred to as “volume change temporary maximum value”.

  Next, the initial cuff pressure determining unit 102 pressurizes the air bag 20 by controlling the driving of the actuator 52 via the actuator driving circuit 53 (step S102). At the stage of pressurizing the air bladder 20, the initial cuff pressure determination unit 102 detects the arterial volume signal Si input from the received light amount detection circuit 44 (step S103). The initial cuff pressure determining unit 102 further calculates a volume change signal Sii based on the arterial volume signal Si.

  The initial cuff pressure determination unit 102 determines whether or not the value of the volume change signal Sii is equal to or larger than the volume change temporary maximum value stored in the memory unit 120 (step S104). If it is determined that the value of volume change signal Sii is greater than or equal to the temporary maximum value of volume change (YES in step S104), the process proceeds to step S105. On the other hand, when it is determined that the volume change signal Sii is less than the volume change temporary maximum value (NO in step S104), the process proceeds to step S106.

  In step S105, the initial cuff pressure determination unit 102 updates the volume change temporary maximum value and overwrites and records the cuff pressure at that time. When this process ends, the process moves to a step S106.

  In step S106, the initial cuff pressure determination unit 102 determines whether or not the cuff pressure is equal to or greater than a predetermined value (a predetermined value P1 (for example, 200 mmHg) in FIG. 6). If it is determined that the cuff pressure has not reached predetermined value P1 (NO in step S106), the process returns to step S102. On the other hand, when it is determined that the cuff pressure is greater than or equal to predetermined value P1 (YES in step S106), the process proceeds to step S107.

  In step S107, the initial cuff pressure determination unit 102 finalizes the volume change temporary maximum value Siim finally recorded in step S105 as a maximum value, and at the time tm when the volume change temporary maximum value Siim is detected. Is determined as the initial cuff pressure Pcm. The initial cuff pressure determination unit 102 further sets the threshold value of the volume change signal Sii described above based on the volume change temporary maximum value Siim. When the process of step S107 ends, the process is returned to the main routine.

  As shown in FIG. 4, when the initial cuff pressure determination process as described above is completed, the cuff pressure initial setting unit 104 controls the driving of the actuator 52 via the actuator drive circuit 53 to change the cuff pressure to the initial cuff pressure. It matches with Pcm (step S5). Referring to FIG. 6, cuff pressure initial setting unit 104 stops driving of actuator 52 at time t1 when the cuff pressure is set to initial cuff pressure Pcm. Thus, when the cuff pressure is set to the initial cuff pressure Pcm, the volume change signal Sii is maximized.

  When the cuff pressure is set to the initial cuff pressure Pcm, servo control of the cuff pressure is started (step S6). Specifically, the servo control unit 106 detects the arterial volume signal Si and calculates the volume change signal Sii, and outputs a control signal to the actuator drive circuit 53 to control the drive of the actuator 52. Here, the actuator 52 is driven at a high speed so that the value of the volume change signal Sii is equal to or less than a threshold value (preferably approximately zero). FIG. 6 shows that servo control is started from time t2.

  In parallel with such servo control, the servo control unit 106 determines whether the calculated volume change signal Sii is equal to or less than the above-described threshold value. That is, it is determined whether or not the value of the volume change signal Sii is close to zero. When it is determined that the calculated volume change signal Sii is equal to or less than the above-described threshold value (YES in step S7), the blood pressure acquisition unit 108 determines the cuff pressure at that time as the blood pressure and stores it in the memory unit 120. (Step S8). When the process of step S8 ends, the process proceeds to step S9. On the other hand, when it is determined that the calculated volume change signal Sii exceeds the above-described threshold value (NO in step S7), the process proceeds to step S9. After time t3 shown in FIG. 6, the value of the volume change signal Sii becomes nearly zero by performing servo control for a predetermined time or more. Therefore, the cuff pressure Pc after time t3 is acquired as the blood pressure.

  In step S9, the servo control unit 106 determines whether or not the stop switch 133 has been pressed. If it is determined that stop switch 133 has not been pressed (NO in step S9), the process returns to step S6. If it is determined that stop switch 133 is pressed (YES in step S9), the series of blood pressure measurement processes is terminated.

  As described above, by using the sphygmomanometer 1A in the present embodiment, the sphygmomanometer based on the volume compensation method capable of continuously measuring blood pressure with high accuracy even when the wrist is employed as the measurement site. It can be.

  As described above, in the sphygmomanometer 1A according to the present embodiment, the cuff pressure determined as the blood pressure is recorded in the memory unit 120 in time series, but as a recording method of the measured blood pressure data, It is not limited to such a form. For example, blood pressure information other than blood pressure data obtained continuously and the blood pressure data may be associated with each other and recorded in the memory unit 120, or other blood pressure information calculated based on the blood pressure data may be Data may be recorded in the memory unit 120 separately. Here, the other blood pressure information includes, for example, the highest blood pressure and the lowest blood pressure, the pulse rate, and the AI (Augmentation Index) value for each pulse wave of one beat. In addition to recording in the memory unit 120, blood pressure data may be displayed on the display unit 110 in real time as a measurement result.

  In the sphygmomanometer 1A according to the present embodiment, the blood pressure measurement process is terminated when the pressing of the stop switch 133 is detected. However, the blood pressure measurement is performed when a predetermined time elapses after the servo control is started. The processing may be ended.

  FIG. 7A is a diagram illustrating a data structure of each measurement data of the sphygmomanometer according to the present embodiment, and FIG. 7B is a diagram illustrating a data structure of a blood pressure information field included in the measurement data. . Next, with reference to FIG. 7A and FIG. 7B, a data structure of measurement data to be stored in the memory unit by executing the blood pressure measurement process described above will be described.

  As shown in FIG. 7A, each of the measurement data 300 stored in the memory unit 120 includes, for example, three fields 301 to 303 of “ID information”, “recording date / time”, and “blood pressure information”. The contents of each field are outlined. The “ID information” field 301 stores an identification number for specifying each measurement data, and the “recording date” field 302 is each measurement data timed by a clock (not shown). Stores information such as the measurement start date and time and the measurement period. The “blood pressure information” field 303 stores time-series blood pressure data, that is, continuous blood pressure (pulse wave) data.

  As shown in FIG. 7B, the blood pressure information field 303 has an area 304 for storing “time data” and an area 305 for storing “blood pressure data”. In the area 304, a plurality of time data 1, 2, 3,..., N corresponding to the sampling period are stored. In the area 305, blood pressure data BD (1), BD (2),..., BD (n) are stored in association with each time data of the area 304. In the area 305, an area indicated by “−” indicates that the volume change signal at that time exceeds the threshold and is not recorded as blood pressure. In addition, as a storage form, it is not limited to such an example, What kind of storage form may be sufficient if time (time) and blood pressure are matched and memorize | stored.

  In the sphygmomanometer 1A according to the present embodiment, since the initial cuff pressure is determined by the initial cuff pressure determining unit 102 every time measurement is performed, an appropriate cuff pressure is initially set for servo control of the cuff pressure. Can be set as cuff pressure. Here, in the sphygmomanometer 1A in the present embodiment, the cuff pressure at the time when the amplitude of the arterial volume becomes maximum when the cuff pressure is variably controlled is set to the initial cuff pressure. In addition, when the cuff pressure is variably controlled, the minimum blood pressure may be calculated based on a so-called oscillometric method, and the cuff pressure having the same value as the minimum blood pressure may be set as the initial cuff pressure. The maximum blood pressure may be calculated in addition to the blood pressure, and the cuff pressure having the same value as the average blood pressure, which is an average value of the maximum blood pressure and the minimum blood pressure, may be set as the initial cuff pressure.

  However, as described above, the initial cuff pressure is not necessarily configured to be determined for each measurement, and the initial cuff pressure is set based on the past measurement results stored in the memory unit 120. You may comprise. More specifically, for example, the initial cuff pressure may be set based on the continuous blood pressure acquired in the measurement performed immediately before. As described above, when the initial cuff pressure is set based on the past blood pressure information, it is not necessary to increase the cuff pressure to a predetermined value P1 (for example, 200 mmHg). It is possible to set a state close to a state in which the pressure is balanced, and it is possible to reduce the restraint on the measurement site of the subject.

(Embodiment 2)
FIG. 8 is a schematic cross-sectional view in the measurement state of the sphygmomanometer in the second embodiment of the present invention. In addition, the same code | symbol is attached | subjected in the figure about the part similar to the blood pressure meter 1A in the above-mentioned Embodiment 1, and the description is not repeated here.

  As shown in FIG. 8, sphygmomanometer 1B in the present embodiment is provided with mounting tool 15 for mounting on wrist 200, unlike sphygmomanometer 1A in the first embodiment described above. The wearing tool 15 is assigned to the lower restraining member 16 that is assigned to the outside of the wrist 200 (the portion that is continuous with the back of the hand of the wrist 200) and the inside of the wrist 200 (the portion that is continuous with the palm of the hand of the wrist 200). The lower restraint member 16 and the upper restraint member 17 are each formed in a curved shape so as to fit along the wrist 200. Each of the lower restraining member 16 and the upper restraining member 17 has one end in the circumferential direction connected by a shaft support portion 16a and a rotating shaft 17a, and the other end in the circumferential direction is detachably fixed by a fastening member 18. Has been. A support frame portion 17b is provided at a predetermined position of the upper restraining member 17, and a main body of an actuator 52 as a pressing mechanism is fixed to an upper predetermined position of the support frame portion 17b.

  As described above, when the wearing tool 15 attached to the wrist 200 is used instead of the mounting table 10 and the support frame 11 of the sphygmomanometer 1A in the first embodiment as in the sphygmomanometer 1B in the present embodiment. In addition, the same effect as in the first embodiment can be obtained. Therefore, by adopting a configuration like the sphygmomanometer 1B in the present embodiment, it is possible to continuously measure blood pressure without using a mounting table mounted on a mounting surface such as a table. A sphygmomanometer that is more portable.

(Embodiment 3)
FIG. 9 is a schematic cross-sectional view in the measurement state of the sphygmomanometer according to Embodiment 3 of the present invention, and FIG. 10 is a block diagram showing a hardware configuration of the sphygmomanometer shown in FIG. In addition, the same code | symbol is attached | subjected in the figure about the part similar to the blood pressure meter 1A in the above-mentioned Embodiment 1, and the description is not repeated here.

  As shown in FIGS. 9 and 10, sphygmomanometer 1 </ b> C according to the present embodiment variably adjusts the relative position of actuator 52 to wrist 200 in addition to actuator 52 that presses air bag 20 toward wrist 200. An auxiliary actuator 62, an auxiliary actuator drive circuit 63 for driving the auxiliary actuator 62, and an auxiliary encoder 64. The auxiliary actuator 62 is used to match the cuff pressure with the initial cuff pressure when performing the servo control described above.

  Specifically, as shown in FIG. 9, in the sphygmomanometer 1C according to the present embodiment, support columns 12A and 12B are erected at positions where the recess 10a on the mounting table 10 is sandwiched. , 12B and a movable frame 13 are attached so that the fixed frame 14 is fixed to the upper ends of the columns 12A, 12B. An actuator 52 is fixed to the movable frame 13, and an auxiliary actuator 62 is fixed to the fixed frame 14. The auxiliary actuator 62 has a drive shaft 62 a that is driven in the axial direction, and the tip thereof is fixed to the movable frame 13. As shown in FIG. 10, the auxiliary actuator drive circuit 63 drives the auxiliary actuator 62 based on the control signal of the control unit 100, and the auxiliary encoder 64 detects the position of the drive shaft 62a of the auxiliary actuator 62 and detects it. The position information is output to the control unit 100.

  In the sphygmomanometer 1C according to the present embodiment, after the initial cuff pressure is determined, the driving of the actuator 52 is stopped, and then the auxiliary actuator 62 is driven to move the movable frame 13 in the direction of arrow B in the figure. Twenty cuff pressures are configured to match the initial cuff pressure. In the initial cuff pressure determination process, the cuff pressure may be variably controlled by driving the auxiliary actuator 62. With this configuration, since the stroke of the actuator 52 driven during servo control can be set short, it becomes possible to use a small actuator, improving its controllability and improving the device. It can be configured more compactly.

(Embodiment 4)
FIG. 11 is a schematic cross-sectional view in the measurement state of the sphygmomanometer according to Embodiment 4 of the present invention, and FIG. 12 is a block diagram showing a hardware configuration of the sphygmomanometer shown in FIG. In addition, the same code | symbol is attached | subjected in the figure about the part similar to the blood pressure meter 1A in the above-mentioned Embodiment 1, and the description is not repeated here.

  As shown in FIGS. 11 and 12, the sphygmomanometer 1D according to the present embodiment includes a pressurizing pump 32 and an exhaust valve in addition to the pressing mechanism using the actuator 52 described above as a mechanism for pressurizing the air bladder 20. Further, a pressurizing / depressurizing mechanism 33 is provided. The operation of the pressure pump 32 is controlled by a pressure pump drive circuit 35, and the operation of the exhaust valve 33 is controlled by an exhaust valve drive circuit 36.

  The pressurizing pump 32 is connected to the air bladder 20 via the air pipe 21 and pressurizes the air bladder 20 by sending air into the air bladder 20. The exhaust valve 33 is connected to the air bag 20 through the air pipe 21 and decompresses the air bag 20 by discharging the air inside the air bag 20 to the outside. The pressurization pump drive circuit 35 drives the pressurization pump 32 based on the control signal of the control unit 100. The exhaust valve drive circuit 36 drives the exhaust valve 33 based on the control signal of the control unit 100.

  In the sphygmomanometer 1D according to the present embodiment, when a process for determining the initial cuff pressure and a process for matching the cuff pressure with the initial cuff pressure are performed, the pressure increasing / decreasing mechanism including the pressurizing pump 32 and the exhaust valve 33 is provided. A pressing mechanism comprising the actuator 52 is used when processing for performing cuff pressure servo control is performed.

  FIG. 13 is a block diagram showing a functional block configuration of the sphygmomanometer shown in FIG. Next, with reference to FIG. 13, the configuration of the functional block of the sphygmomanometer in the present embodiment will be described, and a control unit for determining the initial cuff pressure and for matching the cuff pressure with the initial cuff pressure and The operation of the pressure increasing / decreasing mechanism will be described.

  As shown in FIG. 13, the control unit 100 continuously measures the blood pressure, an initial cuff pressure determining unit 102 that determines an initial cuff pressure, a cuff pressure initial setting unit 104 that matches the cuff pressure with the initial cuff pressure, and the like. Therefore, a servo control unit 106 that servo-controls the cuff pressure and a blood pressure acquisition unit 108 that continuously acquires blood pressure are included. In FIG. 13, only the functional blocks that directly exchange signals with the initial cuff pressure determination unit 102, the cuff pressure initial setting unit 104, the servo control unit 106, and the blood pressure acquisition unit 108 are illustrated. ing.

  The initial cuff pressure determination unit 102 variably controls the cuff pressure using the pressure increasing / decreasing mechanism described above, and the cuff pressure information detected by using the pressure sensor 31 at that time, and the light emitting element 41 and the light receiving element 42. Is used to set the initial cuff pressure based on the detected arterial volume information. Specifically, the initial cuff pressure determination unit 102 gives a command to drive the pressurization pump 32 to the pressurization pump drive circuit 35, and based on this, the pressurization pump 32 pressurizes the air bag 20, The pressurization is continued until the pressure reaches a predetermined value (for example, 200 mmHg). At that time, the initial cuff pressure determination unit 102 gives a command to drive the light emitting element 41 to the light emitting element drive circuit 43, detects the cuff pressure based on the signal input from the oscillation circuit 34, and receives the received light amount. An arterial volume signal is detected based on the signal input from 44, a volume change signal is calculated based on the arterial volume signal, and an initial cuff pressure is determined based on the volume change signal. The initial cuff pressure determination unit 102 outputs the determined initial cuff pressure to the cuff pressure initial setting unit 104.

  After receiving the input of the initial cuff pressure, the cuff pressure initial setting unit 104 matches the cuff pressure with the initial cuff pressure using the pressure increasing / decreasing mechanism. Specifically, the cuff pressure initial setting unit 104 receives an input of the determined initial cuff pressure from the initial cuff pressure determination unit 102, gives a command to drive the exhaust valve 33 to the exhaust valve drive circuit 36, and The exhaust valve 33 exhausts the air inside the air bag 20 based on the above, detects the cuff pressure based on the signal input from the oscillation circuit 34, and the exhaust valve 33 when the cuff pressure matches the initial cuff pressure. Is closed. After matching the cuff pressure with the target value, the cuff pressure initial setting unit 104 outputs a signal indicating that the initial setting of the cuff pressure is completed to the servo control unit 106.

  Note that the functions and operations of the servo control unit 106 and the blood pressure acquisition unit 108 are the same as those in the above-described first embodiment, and thus description thereof is omitted here.

  Even in the case of the sphygmomanometer 1D having the above-described configuration, the same effect as that obtained when the sphygmomanometer 1A in the first embodiment described above is obtained. In addition, when the process for determining the initial cuff pressure and the process for matching the cuff pressure to the initial cuff pressure are executed, a pressurizing / depressurizing mechanism including the pressurizing pump 32 and the exhaust valve 33 is used, so that it can be performed easily and quickly. The initial cuff pressure can be determined and set to the initial cuff pressure.

  In the first to fourth embodiments described above, the case where the present invention is applied to a so-called wrist-type blood pressure monitor that employs a wrist as a part to be measured has been described as an example. It is also possible to apply the present invention to other sphygmomanometers that employ the extremities as the measurement site. Examples of the limbs other than the fingers include ankles, upper arms, and thighs in addition to the wrists described above.

  In the first to fourth embodiments described above, a blood pressure monitor using a photoelectric sensor including a light-emitting element and a light-receiving element has been described as an example of an arterial volume detection unit. However, as an arterial volume detection unit, In addition to this, it is also possible to use an impedance measurement mechanism or the like that detects fluctuations in arterial volume by measuring fluctuations in bioelectrical impedance using electrodes.

  Thus, the above-described embodiments disclosed herein are illustrative in all respects and are not restrictive. The technical scope of the present invention is defined by the terms of the claims, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is a schematic diagram which shows the structure of the blood pressure meter in Embodiment 1 of this invention. It is a block diagram which shows the structure of the hardware of the blood pressure meter in Embodiment 1 of this invention. It is a block diagram which shows the structure of the functional block of the sphygmomanometer in Embodiment 1 of this invention. It is a flowchart which shows the blood pressure measurement process of the sphygmomanometer in Embodiment 1 of this invention. It is a flowchart which shows the determination process of an initial cuff pressure. It is a schematic diagram for demonstrating the determination process of an initial cuff pressure. It is a figure which shows the data structure of each measurement data of the sphygmomanometer in Embodiment 1 of this invention. It is a schematic diagram which shows the structure of the blood pressure meter in Embodiment 2 of this invention. It is a schematic diagram which shows the structure of the blood pressure meter in Embodiment 3 of this invention. It is a block diagram which shows the structure of the hardware of the blood pressure meter in Embodiment 3 of this invention. It is a schematic diagram which shows the structure of the blood pressure meter in Embodiment 4 of this invention. It is a block diagram which shows the structure of the hardware of the blood pressure meter in Embodiment 4 of this invention. It is a block diagram which shows the structure of the functional block of the sphygmomanometer in Embodiment 4 of this invention. It is a figure which shows the shape of a general pulse wave. It is a figure which shows the example of the cuff compliance at the time of employ | adopting a wrist as a to-be-measured site | part. It is a figure which shows the flow volume-pressure characteristic at the time of using the pressurization pressure reduction mechanism of an open loop system.

Explanation of symbols

  1A to 1D Blood pressure monitor, 10 mounting table, 10a recess, 11 support frame, 12A, 12B strut, 13 movable frame, 14 fixed frame, 15 mounting tool, 16 lower restraint member, 16a shaft support, 17 upper restraint member, 17a Rotating shaft, 17b Support frame, 18 Fastening member, 20 Air bag, 21 Air tube, 31 Pressure sensor, 32 Pressure pump, 33 Exhaust valve, 34 Oscillation circuit, 35 Pressure pump drive circuit, 36 Exhaust valve drive circuit , 41 Light emitting element, 42 Light receiving element, 43 Light emitting element drive circuit, 44 Light reception amount detection circuit, 51 Press block, 51a Press surface, 52 Actuator, 52a Drive shaft, 53 Actuator drive circuit, 54 Encoder, 62 Auxiliary actuator, 62a drive Axis, 63 Auxiliary actuator drive circuit, 64 Auxiliary encoder, 100 Control unit, 1 2 initial cuff pressure determination unit, 104 cuff pressure initial setting unit, 106 servo control unit, 108 blood pressure acquisition unit, 110 display unit, 120 memory unit, 130 operation unit, 131 power switch, 132 measurement switch, 133 stop switch, 134 memory Switch, 140 power, 200 wrist, 210 radius, 212 radial artery, 220 ulna, 222 ulnar artery, 230 tendon.

Claims (14)

A blood pressure measurement device capable of measuring the blood pressure of a subject,
A fluid bag;
A pressing mechanism for pressing the fluid bag toward the measurement site;
A cuff pressure detector that detects a cuff pressure that is an internal pressure of the fluid bag;
An arterial volume detector that detects the volume of the artery extending through the measurement site;
A controller for controlling the driving of the pressing mechanism and continuously acquiring the blood pressure of the subject,
The pressing mechanism includes a pressing block having a pressing surface for pressing the fluid bag, and an actuator for driving the pressing block,
The control unit includes a cuff pressure initial setting unit that matches the cuff pressure with a predetermined initial cuff pressure, and the arterial volume information detected by the arterial volume detection unit after matching the cuff pressure with the initial cuff pressure. And a servo control unit that continuously adjusts the cuff pressure by controlling the drive of the actuator so that the fluctuation of the arterial volume is suppressed, and the servo control of the cuff pressure by the servo control unit is being performed. A blood pressure acquisition unit that continuously acquires the blood pressure of the subject based on the cuff pressure information detected by the cuff pressure detection unit,
The blood pressure measuring device, wherein the fluid bag is completely covered by the pressing surface in a state where the fluid bag is pressed against the measurement site by the pressing block.   2. The blood pressure measurement according to claim 1, wherein the fluid bag is hermetically sealed so that the fluid sealed inside is not discharged to the outside during at least servo control of the cuff pressure by the servo control unit. apparatus.   3. The blood pressure measurement device according to claim 1, wherein the cuff pressure initial setting unit matches the cuff pressure with the initial cuff pressure by controlling driving of the actuator. The pressing mechanism further includes an auxiliary actuator that variably adjusts a relative position of the actuator with respect to a measurement site,
3. The blood pressure measurement device according to claim 1, wherein the cuff pressure initial setting unit matches the cuff pressure with the initial cuff pressure by controlling driving of the auxiliary actuator. A pressure increasing / decreasing mechanism for increasing / decreasing the cuff pressure by allowing fluid to enter and exit the fluid bag;
3. The blood pressure measurement device according to claim 1, wherein the cuff pressure initial setting unit matches the cuff pressure with the initial cuff pressure by controlling driving of the pressure increasing / decreasing mechanism.   The control unit controls the cuff pressure variably, based on the cuff pressure information detected by the cuff pressure detection unit and the arterial volume information detected by the arterial volume detection unit at that time. The blood pressure measurement device according to claim 1, further comprising an initial cuff pressure determination unit that determines a cuff pressure.   The blood pressure measurement device according to claim 6, wherein the initial cuff pressure determination unit sets a cuff pressure at the time when the amount of change in the arterial volume becomes maximum to the initial cuff pressure.   The control unit further includes an initial cuff pressure determining unit that variably controls the cuff pressure and determines the initial cuff pressure based on the cuff pressure information detected by the cuff pressure detecting unit at that time. Item 3. The blood pressure measurement device according to item 1 or 2.   The initial cuff pressure determining unit sets the cuff pressure having the same value as the diastolic blood pressure calculated based on the cuff pressure information detected by the cuff pressure detecting unit as the initial cuff pressure. Blood pressure measuring device.   The blood pressure measurement device according to any one of claims 6 to 9, wherein the initial cuff pressure determination unit variably controls the cuff pressure by controlling driving of the actuator. The pressing mechanism further includes an auxiliary actuator that variably adjusts a relative position of the actuator with respect to a measurement site,
The blood pressure measurement device according to any one of claims 6 to 9, wherein the initial cuff pressure determination unit variably controls the cuff pressure by controlling driving of the auxiliary actuator. A pressure increasing / decreasing mechanism for increasing / decreasing the cuff pressure by allowing fluid to enter and exit the fluid bag;
The blood pressure measurement device according to any one of claims 6 to 9, wherein the initial cuff pressure determining unit variably controls the cuff pressure by controlling driving of the pressure increasing / decreasing mechanism.   The blood pressure measurement device according to claim 5 or 12, wherein the pressurizing / depressurizing mechanism includes a pressurizing pump for pressurizing the fluid bag and an exhaust valve for decompressing the fluid bag.   The arterial volume detection unit includes: a light emitting element that irradiates light to the artery; and a light receiving element that receives transmitted light and / or reflected light of the artery irradiated by the light emitting element. The blood pressure measurement device according to any one of 1 to 13.

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