WO2025192156A1 - Blood pressure measurement system and blood pressure measurement method - Google Patents

Abstract

This blood pressure measurement system comprises: a cuff that is to be wrapped around a portion subjected to measurement; a pressure detection unit that detects a cuff pressure inside the cuff; a pressure control unit that controls the cuff pressure; a pulse wave acquisition unit that acquires, from the cuff pressure, pulse wave information of a measurement subject; a first blood pressure calculation unit that calculates a first blood pressure of the measurement subject on the basis of the pulse wave information; a first communication unit that transmits at least the pulse wave information acquired by the pulse wave acquisition unit to an information processing device during the control of the cuff pressure; a second blood pressure calculation unit that calculates, on the basis of the received pulse wave information, a second blood pressure of the measurement subject by a method different from that of the first blood pressure calculation unit; and a second communication unit that transmits the second blood pressure. The blood pressure measurement system, upon receiving the second blood pressure, performs control to display the second blood pressure and stop increasing the pressure of the cuff.

Description

Blood pressure measurement system and blood pressure measurement method

The present invention relates to a blood pressure measurement system and a blood pressure measurement method.

In recent years, health management has become commonplace, using measuring devices to measure information about an individual's physical health, such as blood pressure, and then recording and analyzing the measurement results. One example of such a measuring device is a sphygmomanometer, which measures blood pressure, including systolic blood pressure, based on pressure pulse waves acquired in the process of inflating a cuff attached to the subject's upper arm, wrist, or other part of the body (see, for example, Patent Documents 1 and 2).

The blood pressure monitor disclosed in Patent Document 1 estimates blood pressure values at cuff pressures lower than systolic blood pressure by machine learning the relationship between the pressure pulse wave acquired based on the cuff pressure and the blood pressure value. Specifically, by setting the cuff pressure to, for example, less than 130 mmHg, blood pressure can be measured at a relatively low cuff pressure (lower than systolic blood pressure) even for subjects with high blood pressure, reducing discomfort during blood pressure measurement.

US Patent Application Publication No. 2020/0383579 Japanese Patent Application Publication No. 03-280932

However, advanced estimation processing using machine learning models imposes a heavy computational load, making it difficult to implement such estimation models in a relatively simple device such as a blood pressure monitor.

In light of the problems with conventional technology described above, the present invention aims to provide technology that can measure blood pressure at low cuff pressure without increasing the computational load of the processing implemented in the blood pressure monitor.

In order to solve the above problems, one aspect of the present invention is a blood pressure measurement system as follows:
A blood pressure measurement system including a blood pressure measurement device and an information processing device configured to be communicatively connected to the blood pressure measurement device,
The blood pressure measuring device is
a cuff that is wrapped around the part to be measured;
a pressure detection unit that detects a cuff pressure in the cuff;
a pressure control unit that controls the cuff pressure;
a pulse wave acquiring unit that acquires pulse wave information of the subject from the cuff pressure;
a first blood pressure calculation unit that calculates a first blood pressure of the subject based on the pulse wave information;
a first communication unit that transmits at least the pulse wave information acquired by the pulse wave acquisition unit to the information processing device while controlling the cuff pressure;
a display unit that displays information related to at least the blood pressure of the subject,
The information processing device includes:
a second blood pressure calculation unit that calculates a second blood pressure of the subject based on the received pulse wave information using a method different from that used by the first blood pressure calculation unit;
a second communication unit that transmits the second blood pressure to the blood pressure measurement device,
the display unit displays the second blood pressure when the blood pressure measurement device receives the second blood pressure;
the pressure control unit performs control to stop inflation of the cuff if inflation of the cuff is being performed when the blood pressure measurement device receives the second blood pressure.
A blood pressure measurement system.

Note that "pulse wave information" here may include not only pulse wave amplitude data over time, but also the envelope of the pulse wave amplitude obtained based on that data (hereinafter simply referred to as the envelope).

With this configuration, the sphygmomanometer performs blood pressure calculations that do not require advanced calculations, while an information processing terminal (e.g., PC, tablet terminal, smartphone, etc.) equipped with an advanced calculation processor performs advanced calculations in parallel to estimate blood pressure based only on pulse wave information at low compression, allowing cuff inflation to be stopped once blood pressure estimation is complete. In other words, once blood pressure estimation is completed through advanced calculations by the information processing device, cuff inflation can be stopped early (at the point of low compression), reducing discomfort to the user. Furthermore, because the sphygmomanometer itself calculates blood pressure values using a method with a relatively low calculation load, blood pressure measurement can be performed without problem even if blood pressure estimation by the information processing device is not completed due to a communication error or other reason.

The information processing device further includes a determination means for determining whether a stop condition for stopping the inflation of the cuff is satisfied,
When it is determined that the stop condition is satisfied, the second communication unit transmits a cuff stop signal to the blood pressure measurement device,
The pressure control unit may perform control to stop inflation of the cuff if the cuff is being inflated when the blood pressure measurement device receives the stop signal.

Note that the "stop condition" here can be, for example, when the amount of pulse wave information required to calculate the second blood pressure has been acquired. With this configuration, cuff inflation can be stopped before the blood pressure calculation process in the information processing device is completed (i.e., earlier), further reducing discomfort to the user.

Furthermore, the display unit displays the first blood pressure when the first blood pressure is calculated,
The pressure control unit may perform control to stop pressurizing the cuff if the cuff is being pressurized when the first blood pressure is calculated.

With this configuration, even if the blood pressure calculation process in the information processing device is not completed by the time the blood pressure calculation process in the blood pressure monitor main body is completed, the blood pressure measurement value can be displayed without waiting for the blood pressure calculation process in the information processing device. Furthermore, there is no need to continue to inflate the cuff unnecessarily.

Furthermore, the first blood pressure may be calculated using an oscillometric method, and the second blood pressure may be calculated using an estimation model that has undergone machine learning. This allows the blood pressure monitor body to perform blood pressure calculation processing with a low computational load and high accuracy, and allows cuff inflation to be stopped quickly if blood pressure calculation using the estimation model is completed early, making this an ideal blood pressure measurement system.

Furthermore, when the first blood pressure is calculated by the first blood pressure calculation unit using the oscillometric method, the estimation model may be re-learned using the pulse wave information used to calculate the first blood pressure as a training sample and the value of the first blood pressure as a correct answer label. With this configuration, when a blood pressure value is calculated with high accuracy using the oscillometric method, this data can be effectively utilized.

Furthermore, the blood pressure measurement device further includes, in addition to the first blood pressure calculation unit that uses an oscillometric method,
a third blood pressure calculation unit that calculates a third blood pressure of the subject based on the pulse wave information acquired while the cuff is inflated until the cuff pressure reaches a cuff pressure that is lower than the cuff pressure corresponding to the systolic blood pressure of the subject,
the display unit displays the third blood pressure when the third blood pressure is calculated;
The pressure control unit may perform control to stop pressurizing the cuff if the cuff is being pressurized when the third blood pressure is calculated.

With this configuration, it may be possible to calculate blood pressure using a method that places a relatively low computational load on the blood pressure monitor itself and more quickly than when communicating with an information processing device. In this case, cuff inflation can be stopped as soon as possible (at low pressure) by stopping cuff inflation once blood pressure calculation has been completed by the third blood pressure calculation unit.

The present invention can also be understood as a blood pressure measurement method as follows:
In the blood pressure measuring device,
detecting a cuff pressure in a cuff wrapped around the measurement target part;
applying pressure to the cuff;
Stopping the pressurization;
acquiring pulse wave information of the subject from the cuff pressure;
executing a process of calculating a first blood pressure of the subject based on the pulse wave information;
transmitting the pulse wave information to an information processing device;
displaying the measured blood pressure values;
In the information processing device,
executing a process of calculating a second blood pressure of the subject by a method different from that used to calculate the first blood pressure, based on the received pulse wave information;
When the second blood pressure is calculated, transmitting the second blood pressure to the blood pressure measurement device;
It contains
When the blood pressure measurement device receives the second blood pressure, it displays the second blood pressure as the measured blood pressure value, and if the cuff is being inflated when the second blood pressure is received, it stops the inflating.

The blood pressure measurement method further includes, in the information processing device, a step of determining whether a stop condition for stopping the pressurization is satisfied, and a step of transmitting a stop signal for the pressurization to the blood pressure measurement device when it is determined that the stop condition is satisfied,
If the pressure is being applied when the blood pressure measurement device receives the stop signal, the pressure may be stopped.

Furthermore, the blood pressure measurement method may include, in the blood pressure measurement device, displaying the first blood pressure when the first blood pressure is calculated, and stopping the pressurization if the pressurization is being performed when the first blood pressure is calculated.

Furthermore, in the blood pressure measurement method, the first blood pressure may be calculated using an oscillometric method, and the second blood pressure may be calculated using an estimation model that has undergone machine learning.

The blood pressure measurement method further includes a step of executing, in the blood pressure measurement device, a process of calculating a third blood pressure of the subject based on the pulse wave information acquired while the inflation reaches the cuff pressure that is lower than the cuff pressure corresponding to a systolic blood pressure of the subject,
The blood pressure measurement device may display the third blood pressure when the third blood pressure is calculated, and may stop the inflation of the cuff if the cuff is being inflated when the third blood pressure is calculated.

The present invention can also be seen as a program for causing a computer to execute the above method, or a computer-readable recording medium on which such a program is non-temporarily recorded. Furthermore, the above configurations and processes can be combined with each other to constitute the present invention, provided that no technical contradictions arise.

According to the present invention, blood pressure can be measured at low cuff pressure without increasing the computational load on the blood pressure monitor.

FIG. 1 is a schematic diagram illustrating a schematic configuration of a blood pressure measurement system according to a first embodiment. 2A and 2B are block diagrams illustrating an example of functional modules included in the blood pressure measurement device and the smartphone according to the first embodiment; FIG. 3 is a schematic diagram showing the relationship between the cuff pressure and the pressure pulse wave in the blood pressure measurement device according to the first embodiment. FIG. 4 is a flowchart illustrating the flow of a blood pressure measurement process in the blood pressure measurement system according to the first embodiment. FIG. 5 is a block diagram illustrating an example of functional modules included in a smartphone according to the second embodiment. FIG. 6 is a flowchart illustrating the flow of a blood pressure measurement process in the blood pressure measurement system according to the second embodiment. FIG. 7 is a block diagram illustrating an example of a functional module included in the blood pressure measurement device according to the third embodiment. FIG. 8 is a flowchart illustrating the flow of a blood pressure measurement process in the blood pressure measurement system according to the third embodiment.

Example 1
Specific examples of the present invention will be described below with reference to the drawings. However, unless otherwise specified, the dimensions, materials, shapes, relative positions, etc. of the components described in these examples are not intended to limit the scope of the present invention.

(System configuration)
1 is a schematic diagram showing the configuration of a blood pressure measurement system 1 according to this embodiment. As shown in FIG. 1, the blood pressure measurement system 1 includes a blood pressure measurement device 10 and a smartphone 50 as an example of an information processing device, which are configured to be communicably connected.

(Blood pressure measuring device)
As shown in FIG. 1 , the blood pressure measurement device 10 includes, as its hardware configuration, a cuff 11, a pressure sensor 12, a pressure pump 13, an exhaust valve 14, an air tube 15, an oscillator circuit 21, a pump drive circuit 22, a valve drive circuit 23, a display 25, a memory 27, an operation switch 26, a power supply 24, a communication IF (Interface) 28, and a CPU (Central Processing Unit) 100.

The cuff 11 includes an air bag 11a containing air. A pressure sensor 12 detects the pressure inside the air bag 11a of the cuff 11 (hereinafter referred to as "cuff pressure") via an air tube 15. A pressure pump 13 supplies air to the air bag 11a via the air tube 15. An exhaust valve 14 is a valve that opens and closes to maintain the pressure inside the air bag 11a or to exhaust air from the air bag 11a.

CPU 100 is an example of an arithmetic processing unit for controlling each part of the device. Memory 27 includes a main storage device such as RAM (Random Access Memory) and an auxiliary storage device such as flash memory, and stores programs executed for blood pressure measurement processing, as well as data such as cuff pressure, pressure pulse wave, and blood pressure measurement results.

Display 25 is an example of a display device that displays various information such as blood pressure measurement results, and can be, for example, an LCD (Liquid Crystal Display). Operation switch 26 is an example of an input device for inputting various instructions related to the operation of the device, including the execution of blood pressure measurement. A touch panel display can also be used as display 25 and operation switch 26. Power supply 24, which supplies power to each part of the device, such as the CPU, can receive power from an outlet via a wired connection, or can be a battery.

The communication IF 28 functions to establish a communication connection with the smartphone 50, and can employ an appropriate communication interface, such as a wired communication port or a wireless communication antenna, depending on the communication network to be connected. The communication IF 28 corresponds to the first communication unit in the present invention. Note that the communication method between the blood pressure measurement device 10 and the smartphone 50 is not particularly limited, but BLE (Bluetooth (registered trademark) Low Energy) communication, for example, can be used.

The oscillator circuit 21 outputs a signal with an oscillation frequency corresponding to the output value of the pressure sensor 12 to the CPU 100. The pump drive circuit 22 controls the drive of the pressure pump 13 based on a control signal output from the CPU 100. The valve drive circuit 23 controls the opening and closing of the exhaust valve 14 based on a control signal output from the CPU 100.

FIG. 2A is a functional block diagram showing the functional modules provided in the CPU 100 of the blood pressure measurement device 10. As shown in FIG. 2A, the CPU 100 includes the functional modules of a pressure detection unit 110, a pressure control unit 120, and a first blood pressure calculation unit 130.

The output signal of the oscillator circuit 21 is input to the pressure detection unit 110. The pressure detection unit 110 detects the oscillation frequency of the input signal and converts the detected oscillation frequency into a pressure value signal. The pressure detection unit 110 includes an HPF unit 111 that extracts and outputs a pressure pulse wave signal by HPF (High Pass Filter) processing the pressure value signal, and an LPF unit 112 that extracts and outputs a cuff pressure signal by LPF (Low Pass Filter) processing the pressure value signal. The pressure pulse wave signal detected in time series by the HPF unit 111 of the pressure detection unit 110 and the cuff pressure signal indicating the cuff pressure detected in time series by the LPF unit 112 are stored in a predetermined area of the memory 27 and transmitted to the smartphone 50 via the communication IF 28. The HPF unit 111 corresponds to the pulse wave acquisition unit of the present invention.

Figure 3 is a graph that schematically shows the relationship between the cuff pressure detected by the pressure detection unit 110 and the pressure pulse wave. Generally, as shown in Figure 3, the diastolic blood pressure (DBP) and systolic blood pressure (SBP) are calculated as the cuff pressure corresponding to a specific fluctuation pattern of the pressure pulse wave.

The pressure control unit 120 controls the operation of the pump drive circuit 22 and the valve drive circuit 23 to control the cuff pressure of the cuff 11.

The first blood pressure calculation unit 130 inputs the pressure pulse wave signal extracted by the HPF unit 111 of the pressure detection unit 110, and processes the input pressure pulse wave signal according to the oscillometric method of measurement under pressure to calculate the diastolic blood pressure (lower blood pressure, DBP) and systolic blood pressure (higher blood pressure, SBP). The oscillometric method is a well-known technique, so a detailed explanation will be omitted.

(Smartphone)
As shown in FIG. 1, the smartphone 50 includes, as its hardware configuration, a CPU 500, a memory 51, a touch panel display 52, a communication IF 53, a power supply 54, and the like.

CPU 500 is an example of an arithmetic processing device for controlling each part of the device. Memory 51 includes a main storage device such as RAM and an auxiliary storage device such as flash memory, and stores various programs and various information such as pressure pulse wave data transmitted from blood pressure measurement device 10, as described below.

The touch panel display 52 functions as an operation unit that accepts various input instructions, and also as a display unit that displays information. The communication IF 53 functions to establish a communication connection with the blood pressure measurement device 10, and can employ an appropriate communication interface depending on the communication network to which it is connected. The communication IF 53 corresponds to the second communication unit in the present invention. The power supply 54 that supplies power to each unit of the device can employ a secondary battery, such as a lithium-ion battery.

FIG. 2B is a functional block diagram showing the functional modules provided in the CPU 500 of the smartphone 50. As shown in FIG. 2B, the CPU 500 includes a functional module of a second blood pressure calculation unit 510.

The second blood pressure calculation unit 510 is an estimation model (so-called AI) that has been trained, for example, by machine learning. The second blood pressure calculation unit 510 receives pressure pulse wave data acquired by the pressure detection unit 110 from the blood pressure measurement device 10 via the communication IF 53, and calculates a blood pressure value based on the pressure pulse wave data up to the point where the amplitude of the pressure pulse wave reaches its maximum value. An example of a blood pressure value calculation method in the second blood pressure calculation unit 510 is described below.

As shown in Figure 3, when the cuff begins to be inflated to measure blood pressure and the cuff pressure is increased, the amplitude of the measured pressure pulse wave first gradually increases and reaches its maximum value (envelope peak). After the amplitude of the pressure pulse wave reaches its maximum value, as the cuff pressure is further increased, the amplitude of the measured pressure pulse wave gradually decreases. The diastolic blood pressure appears after the cuff begins to be inflated and before the amplitude of the pressure pulse wave reaches its maximum value. On the other hand, the systolic blood pressure appears after the amplitude of the pulse wave reaches its maximum value but before the pulse wave completely stops (amplitude becomes 0).

Based on these characteristics of the relationship between the time-series data of the pressure pulse wave and the blood pressure value, the blood pressure of the subject is measured using the blood pressure measurement device 10, and the pulse wave signal up to the time when the envelope of the pressure pulse wave reaches its peak is used as training (sample) data. The blood pressure measurement values (SBP, DBP) calculated using the oscillometric method based on the pulse wave signal obtained when the envelope of the pressure pulse wave exceeds the point corresponding to the systolic blood pressure are used as correct labels (teaching data) for learning, thereby obtaining the second blood pressure calculation unit 510 as an estimation model.

Then, by inputting pressure pulse wave data up until the envelope reaches its peak into the second blood pressure calculation unit 510 (trained estimation model), the diastolic and systolic blood pressure values can be obtained. In other words, since the second blood pressure calculation unit 510 can calculate blood pressure if it has pressure pulse wave data up until the envelope reaches its peak, when the value calculated by the second blood pressure calculation unit 510 is used as the measured value, it is possible to stop inflating the cuff at a low cuff pressure before inflating the cuff until the cuff pressure equals the systolic blood pressure value.

(Blood pressure measurement process)
Next, the flow of blood pressure measurement processing by the blood pressure measurement system 1 in this embodiment will be described with reference to Fig. 4. Fig. 4 is a flowchart showing the flow of blood pressure measurement processing by the blood pressure measurement system 1 in this embodiment. In the blood pressure measurement system 1, the blood pressure measurement device 10 and the smartphone 50 send and receive data and perform blood pressure measurement in cooperation. That is, the following description will be given on the assumption that the blood pressure measurement device 10 and the smartphone 50 are paired and communication between them is established.

In addition, before the flow begins, the subject wraps the cuff 11 around the part to be measured (e.g., the upper arm), performs certain settings using the operation switch 26, and issues a command to start blood pressure measurement. Upon receiving the command to start blood pressure measurement, the blood pressure measurement device 10 performs certain initialization steps, such as opening the exhaust valve 14 and setting the cuff pressure to atmospheric pressure (initial pressure).

When blood pressure measurement is initiated in the blood pressure measurement device 10, the pressure control unit 120 initiates inflation control to inflate the cuff 11 (S111). Furthermore, during the inflation control process, the HPF unit 111 of the pressure detection unit 110 acquires a pressure pulse wave (S112). Then, based on the pressure pulse wave acquired over time, the first blood pressure calculation unit 130 executes a process to calculate a blood pressure value using the oscillometric method (S113). Note that the blood pressure value calculated by the first blood pressure calculation unit 130 corresponds to the first blood pressure of the present invention.

Meanwhile, the pressure pulse wave acquired in step S112 is transmitted to the smartphone 50 via the communication IF 28, and the communication IF 53 of the smartphone 50 receives the pressure pulse wave data (S121). The second blood pressure calculation unit 510 of the smartphone 50 executes a process to calculate (estimate) the blood pressure value using the received pressure pulse wave data as input data (S122). That is, in the blood pressure measurement system 1, measurement of the blood pressure value by the blood pressure measurement device 10 and measurement by the smartphone 50 are performed in parallel.

Following step S122, the second blood pressure calculation unit 510 determines whether or not the estimation of the blood pressure value has been completed (S123). If it is determined that the estimation of the blood pressure value has not yet been completed, the pressure pulse wave is continuously received and the blood pressure estimation process is executed (steps S121, S122). On the other hand, if it is determined in step S123 that the estimation of the blood pressure value has been completed, the CPU 500 transmits the calculated estimated blood pressure value to the blood pressure measurement device 10 via the communication IF 53 (S124), and the series of processes on the smartphone 50 side are temporarily terminated. Note that in this embodiment, the estimated blood pressure value calculated (estimated) by the second blood pressure calculation unit 510 corresponds to the second blood pressure of the present invention.

Returning to the explanation of the processing of the blood pressure measurement device 10, after calculation of the blood pressure value is started in step S113, the pressure control unit 120 determines in step S114 whether calculation of the blood pressure value has been completed (S114). If it is determined that calculation of the blood pressure value has been completed, the pressure control unit 120 controls the pump drive circuit 22 to stop inflating the cuff 11 (S115) and proceeds to step S118.

On the other hand, if it is determined in step S114 that the calculation of the blood pressure value has not yet been completed, the pressure control unit 120 then determines whether or not an estimated blood pressure value has been received from the smartphone 50 (S116). If it is determined that an estimated blood pressure value has not been received, the process of acquiring the pressure pulse wave and calculating the blood pressure value continues (S112, S113). In other words, the pressure control unit 120 continues to inflate the cuff 11 so that DBP and SBP can be calculated.

If it is determined in step S116 that a blood pressure estimate has been received, the pressure control unit 120 controls the pump drive circuit 22 to stop pressurization (S117), and proceeds to step S118. In other words, if the blood pressure calculation process by the first blood pressure calculation unit 130 is ongoing when the blood pressure measurement device 10 receives the blood pressure estimate, that calculation process is stopped.

In step S118, the CPU 100 displays the measurement results (hereinafter simply referred to as the measurement results) including either the blood pressure value calculated by the first blood pressure calculation unit 130 or the estimated blood pressure value calculated by the second blood pressure calculation unit 510 on the display 25 of the blood pressure measurement device 10 (S118). Specifically, if the processing of step S118 is performed after step S115, the DBP and SBP calculated by the first blood pressure calculation unit 130 are displayed, and if the processing of step S118 is performed after step S117, the DBP and SBP calculated by the second blood pressure calculation unit 510 are displayed. The CPU 100 further records the measurement results in a predetermined area of the memory 27 of the blood pressure measurement device 10, and the blood pressure measurement process ends.

(Effects of this Example)
While the second blood pressure calculation unit 510 can estimate blood pressure values (DBP, SBP) based on pressure pulse wave data up until the pulse wave envelope reaches its peak, the first blood pressure calculation unit 130 cannot calculate SBP unless the cuff is inflated until the systolic blood pressure and the cuff pressure become equal, and therefore the blood pressure estimate by the second blood pressure calculation unit 510 is usually calculated earlier. That is, according to the flow of the series of processes in the blood pressure measurement system 1 in this embodiment described above, the pressure control unit 120 can stop inflating in step S117 at a stage where the cuff pressure is relatively low before the systolic blood pressure and the cuff pressure become equal.

Note that the second blood pressure calculation unit 510 requires advanced calculations because it is an estimation model based on machine learning. However, the CPU 500 of the smartphone 50 has sufficient performance as an information processing device, so there is no problem with performing calculations using this estimation model.

However, because the second blood pressure calculation unit 510 is a functional module of the smartphone 50, which is separate from the blood pressure measurement device 10, if there is a communication problem or if blood pressure measurement is performed using only the blood pressure measurement device 10, the second blood pressure calculation unit 510 will not be able to calculate blood pressure (or sending and receiving data will take longer than expected).

Even in such a case, the blood pressure measurement device 10 is equipped with the first blood pressure calculation unit 130, and therefore can calculate blood pressure values using the normal oscillometric method. If the first blood pressure calculation unit 130 calculates blood pressure values for some reason, the pressure pulse wave data acquired during that calculation and the calculated blood pressure values can be used as re-learning data for the second blood pressure calculation unit 510. Specifically, the pressure pulse wave data (up to the envelope peak) may be used as a training sample, and the calculated blood pressure values may be used as correct labels to perform re-learning for the second blood pressure calculation unit 510.

Example 2
Next, a second embodiment of the present invention will be described with reference to Figures 5 and 6. The blood pressure measurement system according to this embodiment has a system configuration similar to that of the first embodiment, including a blood pressure measurement device 10 and a smartphone 50, and the hardware configurations of these devices are also similar to those of the first embodiment. Therefore, the drawings will be reused for components common to the first embodiment, such as the hardware configuration of the system, and the same reference numerals as those of the first embodiment will be used, and a repeated description will be omitted.

As shown in the functional block diagram of Figure 5, the smartphone 50 according to this embodiment differs from the first embodiment in that it includes an inflation stop determination unit 520 as a functional module of the CPU 500. The inflation stop determination unit 520 determines whether a stop condition for stopping inflation of the cuff 11 during blood pressure measurement has been met. Specifically, it determines whether the amount of pressure pulse wave data required for the second blood pressure calculation unit 510 to calculate the blood pressure value, i.e., the pressure pulse wave data up to the peak of the pulse wave envelope, has been received from the blood pressure measurement device 10. If the inflation stop determination unit 520 further determines that the stop condition is met, it generates an inflation stop signal for the pressure control unit 120 of the blood pressure measurement device 10.

Next, the flow of the blood pressure measurement process in this embodiment will be described with reference to Figure 6. Figure 6 is a flowchart showing the flow of the blood pressure measurement process in this embodiment. In this embodiment, the blood pressure measurement process is generally similar to that in Example 1. In other words, the blood pressure measurement device 10 and smartphone 50 work together to perform the blood pressure measurement process.

First, when blood pressure measurement is initiated in the blood pressure measurement device 10, the pressure control unit 120 initiates inflation control to inflate the cuff 11 (step S211). Furthermore, during the inflation control process, the HPF unit 111 of the pressure detection unit 110 acquires a pressure pulse wave (step S212). Then, based on the pressure pulse wave acquired over time, the first blood pressure calculation unit 130 executes a process to calculate a blood pressure value using the oscillometric method (S213).

Meanwhile, the pressure pulse wave acquired in step S212 is transmitted to the smartphone 50 via the communication IF 28, and the communication IF 53 of the smartphone 50 receives the pressure pulse wave data (S221). The inflation stop determination unit 520 of the smartphone 50 then performs calculation processing to determine the inflation stop conditions for the cuff 11 of the blood pressure measurement device 10 based on the received pressure pulse wave data. Specifically, it performs calculations to determine the peak of the pulse wave envelope based on the pressure pulse wave data (S222), and determines whether pressure pulse wave data up to the peak of the pulse wave envelope has been acquired (S223).

If it is determined in step S223 that pressure pulse wave data up to the peak of the pulse wave envelope has not yet been acquired, reception of pressure pulse wave data and calculation to determine the envelope peak continue (S221, S222). On the other hand, if it is determined in step S223 that pressure pulse wave data up to the peak of the pulse wave envelope has been acquired, the inflation stop determination unit 520 generates a command signal to stop inflation of the cuff 11 and transmits it to the blood pressure measurement device 10 via the communication IF 53 (S224).

Next, the second blood pressure calculation unit 510 executes a process to calculate an estimated blood pressure value using the acquired pressure pulse wave data as input data (S225), and transmits the calculated blood pressure value to the blood pressure measurement device 10 via the communication IF 53 (S226), after which the series of processes on the smartphone 50 side are temporarily terminated.

Returning to the explanation of the processing of the blood pressure measurement device 10, after calculation of the blood pressure value is started in step S213, the pressure control unit 120 determines in step S214 whether calculation of the blood pressure value has been completed (S214). If it is determined that calculation of the blood pressure value has been completed, the pressure control unit 120 controls the pump drive circuit 22 to stop inflating the cuff 11 (S215) and proceeds to step S219.

On the other hand, if it is determined in step S214 that the calculation of the blood pressure value has not yet been completed, the pressure control unit 120 then determines whether or not a signal to stop inflating the cuff has been received from the smartphone 50 (S216). If it is determined that a stop signal has not been received, the process of acquiring the pressure pulse wave and calculating the blood pressure value continues (S212, S213). In other words, the pressure control unit 120 continues inflating the cuff 11 so that DBP and SBP can be calculated.

On the other hand, if it is determined in step S216 that a stop signal has been received, the pressure control unit 120 controls the pump drive circuit 22 to stop pressurization (S217). In other words, if the blood pressure calculation process by the first blood pressure calculation unit 130 is ongoing when the blood pressure measurement device 10 receives the stop signal, that calculation process is stopped.

Next, the communication IF 28 receives the estimated blood pressure value calculated by the second blood pressure calculation unit 510 of the smartphone 50 and transmitted from the communication IF 53 (S218), and the process proceeds to step S219.

In step S219, the CPU 100 displays the measurement results, including either the blood pressure value calculated by the first blood pressure calculation unit 130 or the estimated blood pressure value calculated by the second blood pressure calculation unit 510, on the display 25 of the blood pressure measurement device 10 (S219). Specifically, if the processing of step S219 is performed after step S215, the DBP and SBP calculated by the first blood pressure calculation unit 130 are displayed, and if the processing of step S219 is performed after step S218, the DBP and SBP calculated by the second blood pressure calculation unit 510 are displayed. The CPU 100 further records the measurement results in a predetermined area of the memory 27 of the blood pressure measurement device 10, and the blood pressure measurement process ends.

As described above, in this embodiment, once the amount of pressure pulse wave data required for the second blood pressure calculation unit 510 of the smartphone 50 to estimate the blood pressure value has been acquired, a signal to stop inflation of the cuff 11 in the blood pressure measurement device 10 is transmitted (S225) before the estimation of the blood pressure value is completed, thereby stopping inflation of the cuff 11 (S217). In other words, it is possible to stop inflation of the cuff 11 of the blood pressure measurement device 10 more quickly than in Example 1.

Even if the inflation of the cuff 11 stops, the second blood pressure calculation unit 510 has already acquired the amount of pressure pulse wave data necessary for blood pressure estimation, so the calculation (estimation) of the blood pressure value is not affected. The calculated estimated blood pressure value is then sent to the blood pressure measurement device 10 (S218, S226), and the estimated blood pressure value is displayed on the display 25.

Example 3
Next, a third embodiment of the present invention will be described with reference to Figures 7 and 8. The blood pressure measurement system according to this embodiment has a system configuration substantially similar to that of the first embodiment, including the inclusion of a blood pressure measurement device 10 and a smartphone 50, and the respective hardware configurations are also similar to those of the first embodiment. For this reason, the drawings will be reused for components common to the first embodiment, such as the system hardware configuration, and the same reference numerals as those of the first embodiment will be used, and a repeated description will be omitted.

As shown in the functional block diagram of Figure 7, the blood pressure measurement device 10 according to this embodiment differs from Example 1 in that it includes a third blood pressure calculation unit 140 as a functional module of the CPU 100. The third blood pressure calculation unit 140 does not calculate blood pressure using the oscillometric method, but rather calculates (estimates) a blood pressure value based on the pressure pulse wave acquired while the cuff pressure of the cuff 11 reaches a cuff pressure lower than the cuff pressure corresponding to the subject's systolic blood pressure. However, the third blood pressure calculation unit 140 does not perform advanced calculations like a machine-learned estimation model.

Here, the "cuff pressure lower than the cuff pressure corresponding to the systolic blood pressure" can be any cuff pressure, and for example, it may be determined by calculating DBP and using this as a reference. Specifically, the cuff pressure can be calculated using the following method, for example.

As shown in Patent Document 2, RAV, WID, and DFN are known indices obtained based on pressure pulse wave information. These are indices calculated for each beat of the pressure pulse wave, and RAV, WID, and DFN respectively indicate the area, width, and slope of the pulse wave for one beat. Specifically, RAV is the pulse wave area for each beat normalized by amplitude, and is expressed as (pulse wave area / pulse wave amplitude within one beat) x 100. WID is the waveform width, which is the time width from the maximum amplitude until it drops to the threshold, normalized by the pulse wave period, and is expressed as (waveform width / pulse wave period) x 100. DFN is the minimum value of the first derivative of the pressure pulse wave normalized by the pulse wave amplitude, and is expressed as (minimum value from 0 of the first derivative of the pulse wave / pulse wave amplitude of the first derivative of the pulse wave) x 100.

When the cuff pressure that results in DBP is Pd, it is expressed as a function of RAV, WID, and DFN, such as Pd = f(RAV, WID, DFN). Here, Pd is expressed as a function of the three indices RAV, WID, and DFN, but it may also be expressed as any one or two of the indices. The form of the function f is not particularly limited, but by calculating these indices for each beat of the pressure pulse wave acquired by the HPF unit 111, it is possible to determine whether the cuff pressure has reached DBP.

Based on the DBP calculated in this way, the third blood pressure calculation unit 140 can calculate a "cuff pressure lower than the cuff pressure corresponding to the systolic blood pressure" for estimating blood pressure values. When the cuff pressure is P1, the relationship between the cuff pressure value and DBP is expressed by a predetermined relational equation, such as P1 = g(Pd). The form of the function g is not particularly limited, but for example, it may be P1 = αPd, where α is a constant.

As shown in Figure 3, DBP can be detected before the peak in the envelope of the pressure pulse wave, i.e., at a cuff pressure lower than the cuff pressure corresponding to the peak. Furthermore, in the envelope of the pressure pulse wave, the peak occurs before SBP, i.e., the cuff pressure corresponding to the peak is lower than the cuff pressure corresponding to SBP. Taking these points into consideration, P1 may be set as the cuff pressure at which the pulse wave envelope peaks.

Next, the flow of the blood pressure measurement process in this embodiment will be described with reference to Figure 8. Figure 8 is a flowchart showing the flow of the blood pressure measurement process in this embodiment. In this embodiment, the blood pressure measurement process is generally similar to that in Example 1. That is, the blood pressure measurement device 10 and the smartphone 50 work together to perform the blood pressure measurement process. Furthermore, since the process performed by the smartphone 50 below is similar to that in Example 1, the same reference numerals are used and detailed description will be omitted.

First, when blood pressure measurement is started in the blood pressure measurement device 10, the pressure control unit 120 starts inflation control to inflate the cuff 11 (step S311). Furthermore, during the inflation control process, the HPF unit 111 of the pressure detection unit 110 acquires a pressure pulse wave (step S312). Then, based on the pressure pulse wave acquired over time, the third blood pressure calculation unit 140 executes a process to calculate (estimate) a blood pressure value (S313). Note that in this embodiment, the blood pressure value calculated by the third blood pressure calculation unit 140 corresponds to the third blood pressure in the present invention.

Meanwhile, the pressure pulse wave acquired in step S312 is transmitted to the smartphone 50 via the communication IF 28, and the communication IF 53 of the smartphone 50 receives the pressure pulse wave data (S121). The subsequent processing performed by the smartphone 50 is the same as in Example 1.

Returning to the explanation of the processing of the blood pressure measurement device 10, after the blood pressure value estimation process is started in step S313, the pressure control unit 120 determines in step S314 whether or not the blood pressure value estimation has been completed (S314). If it is determined that the blood pressure value estimation has been completed, the pressure control unit 120 controls the pump drive circuit 22 to stop inflating the cuff 11 (S315), and proceeds to step S318.

On the other hand, if it is determined in step S314 that the blood pressure estimation has not yet been completed, the pressure control unit 120 then determines whether or not a blood pressure estimate has been received from the smartphone 50 (S316). If it is determined that a blood pressure estimate has not been received, the process of acquiring the pressure pulse wave and calculating the blood pressure value continues (S312, S313). That is, the pressure control unit 120 continues inflating the cuff 11 so that DBP and SBP can be calculated.

If it is determined in step S316 that a blood pressure estimate has been received, the pressure control unit 120 controls the pump drive circuit 22 to stop pressurization (S317) and proceeds to step S318. In other words, if the blood pressure calculation process by the third blood pressure calculation unit 140 is ongoing when the blood pressure measurement device 10 receives a blood pressure estimate from the smartphone 50, that calculation process is stopped.

In step S318, the CPU 100 displays the measurement results (hereinafter simply referred to as the measurement results) including either the blood pressure value calculated by the third blood pressure calculation unit 140 or the estimated blood pressure value calculated by the second blood pressure calculation unit 510 on the display 25 of the blood pressure measurement device 10 (S318). Specifically, if the processing of step S318 is performed after step S315, the DBP and SBP calculated by the third blood pressure calculation unit 140 are displayed, and if the processing of step S318 is performed after step S317, the DBP and SBP calculated by the second blood pressure calculation unit 510 are displayed. The CPU 100 further records the measurement results in a predetermined area of the memory 27 of the blood pressure measurement device 10, and the blood pressure measurement process ends.

As described above, in the blood pressure measurement process according to this embodiment, the blood pressure measurement device 10 calculates (estimates) the blood pressure value earlier than with the oscillometric method, without inflating the cuff 11 to a cuff pressure equal to the systolic blood pressure. This means that it may be possible to calculate blood pressure earlier than when communicating with the smartphone 50 and obtaining the blood pressure estimation result from the second blood pressure calculation unit 510. In this case, inflation of the cuff 11 is stopped when the blood pressure calculation (estimate) is completed by the third blood pressure calculation unit 140 (S315), so inflation of the cuff 11 can be stopped earlier (at a low compression state).

In addition, the blood pressure measurement device 10 according to this embodiment also includes a first blood pressure calculation unit 130 that calculates blood pressure using the oscillometric method. Therefore, when blood pressure calculations by the second blood pressure calculation unit 510 and the third blood pressure calculation unit 140 do not work properly (when there is doubt about the accuracy of the estimated value), or when performing calibration, it is possible to measure blood pressure values with high accuracy using the oscillometric method as appropriate.

<Others>
The above examples are merely illustrative of the present invention, and the present invention is not limited to the specific embodiments described above. Various modifications and combinations of the present invention are possible within the scope of the technical concept. For example, the configuration of Example 2 may be combined with the invention of Example 3, so that the smartphone 50 of Example 3 includes an inflation stop determination unit 520 and transmits an inflation stop signal for the cuff 11 before the second blood pressure calculation unit 510 estimates the blood pressure value.

Furthermore, in the above examples, the first blood pressure calculation unit 130 is configured to measure blood pressure using the oscillometric method, but it can also be configured to measure blood pressure using other methods. Specifically, the first blood pressure calculation unit 130 may calculate blood pressure values using, for example, the Korotkoff method (auscultation method), the volume compensation method, etc.

Furthermore, the first blood pressure calculation unit 130 in the above-described first and second embodiments may be configured similarly to the third blood pressure calculation unit 140 in the third embodiment. That is, the first blood pressure calculation unit 130 that performs blood pressure measurement using the oscillometric method in the third embodiment may be omitted. Furthermore, the second blood pressure calculation unit 510 in the above-described first and second embodiments may be configured similarly to the third blood pressure calculation unit 140 in the third embodiment.

REFERENCE SIGNS LIST 1... Blood pressure measurement system 10... Blood pressure measurement device 11... Cuff 15... Air tube 28, 53... Communication IF
100, 500...CPU
110: Pressure detection unit 120: Pressure control unit 130: First blood pressure calculation unit 140: Third blood pressure calculation unit 50: Smartphone 510: Second blood pressure calculation unit 520: Pressurization stop determination unit

Claims (11)

A blood pressure measurement system including a blood pressure measurement device and an information processing device configured to be communicatively connected to the blood pressure measurement device,
The blood pressure measuring device is
a cuff that is wrapped around the part to be measured;
a pressure detection unit that detects a cuff pressure in the cuff;
a pressure control unit that controls the cuff pressure;
a pulse wave acquiring unit that acquires pulse wave information of the subject from the cuff pressure;
a first blood pressure calculation unit that calculates a first blood pressure of the subject based on the pulse wave information;
a first communication unit that transmits at least the pulse wave information acquired by the pulse wave acquisition unit to the information processing device while controlling the cuff pressure;
a display unit that displays information related to at least the blood pressure of the subject,
The information processing device includes:
a second blood pressure calculation unit that calculates a second blood pressure of the subject based on the received pulse wave information using a method different from that used by the first blood pressure calculation unit;
a second communication unit that transmits the second blood pressure to the blood pressure measurement device,
the display unit displays the second blood pressure when the blood pressure measurement device receives the second blood pressure;
the pressure control unit performs control to stop inflation of the cuff if inflation of the cuff is being performed when the blood pressure measurement device receives the second blood pressure.
Blood pressure measurement system. The information processing device further includes a determination means for determining whether a stop condition for stopping the inflation of the cuff is satisfied,
When it is determined that the stop condition is satisfied, the second communication unit transmits a cuff stop signal to the blood pressure measurement device,
the pressure control unit performs control to stop inflation of the cuff if inflation of the cuff is being performed when the blood pressure measurement device receives the stop signal.
The blood pressure measurement system according to claim 1 . the display unit displays the first blood pressure when the first blood pressure is calculated;
the pressure control unit performs control to stop pressurizing the cuff if pressurizing the cuff is being performed when the first blood pressure is calculated.
The blood pressure measurement system according to claim 1 . the first blood pressure is calculated by an oscillometric method,
The second blood pressure is calculated using an estimation model that has undergone machine learning.
The blood pressure measurement system according to claim 1 . The blood pressure measuring device is
a third blood pressure calculation unit that calculates a third blood pressure of the subject based on the pulse wave information acquired while the cuff is inflated until the cuff pressure reaches a cuff pressure that is lower than the cuff pressure corresponding to the systolic blood pressure of the subject,
the display unit displays the third blood pressure when the third blood pressure is calculated;
the pressure control unit performs control to stop pressurizing the cuff if the cuff is being pressurized when the third blood pressure is calculated.
The blood pressure measurement system according to claim 4 . The estimation model is
When the first blood pressure is calculated by the first blood pressure calculation unit, the pulse wave information used in calculating the first blood pressure is used as a training sample, and the value of the first blood pressure is used as a correct label for re-learning.
The blood pressure measurement system according to claim 4 . In the blood pressure measuring device,
detecting a cuff pressure in a cuff wrapped around the measurement target part;
applying pressure to the cuff;
Stopping the pressurization;
acquiring pulse wave information of the subject from the cuff pressure;
executing a process of calculating a first blood pressure of the subject based on the pulse wave information;
transmitting the pulse wave information to an information processing device;
displaying the measured blood pressure values;
In the information processing device,
executing a process of calculating a second blood pressure of the subject by a method different from that used to calculate the first blood pressure, based on the received pulse wave information;
When the second blood pressure is calculated, transmitting the second blood pressure to the blood pressure measurement device;
It contains
When the blood pressure measurement device receives the second blood pressure, it displays the second blood pressure as the measured blood pressure value, and if the cuff is being inflated when the second blood pressure is received, it stops the inflating.
How to measure blood pressure. In the information processing device,
determining whether a stop condition for stopping the pressurization is satisfied;
transmitting a signal to stop the pressurization to the blood pressure measurement device when it is determined that the stop condition is satisfied;
It further includes
If the pressurization is being performed when the blood pressure measurement device receives the stop signal, the pressurization is stopped.
The blood pressure measurement method according to claim 7. In the blood pressure measurement device, when the first blood pressure is calculated, the first blood pressure is displayed, and when the pressurization is being performed when the first blood pressure is calculated, the pressurization is stopped.
The blood pressure measurement method according to claim 7. the first blood pressure is calculated by an oscillometric method,
The second blood pressure is calculated using an estimation model that has undergone machine learning.
The blood pressure measurement method according to claim 7. In the blood pressure measuring device,
a step of executing a process of calculating a third blood pressure of the subject based on the pulse wave information acquired while the pressurization is being continued until the cuff pressure reaches a value lower than the cuff pressure corresponding to the systolic blood pressure of the subject;
It further includes
the blood pressure measurement device displays the third blood pressure when the third blood pressure is calculated, and stops the inflation of the cuff when the third blood pressure is calculated and the cuff is being inflated.
The blood pressure measurement method according to claim 10.