WO2016047302A1 - Cardiac output measuring device and cardiac output measuring method - Google Patents

Abstract

In the cardiac output measuring device and cardiac output measuring method according to the present invention, an electrocardiographic measuring unit and a plethysmographic measuring unit are separate elements that are connected with the ability to communicate with each other by wireless. On the basis of a first measurement result relating to an electrocardiogram measured by the electrocardiographic measuring unit and a second measurement result relating to a pulse wave measured by the plethysmographic measuring unit, a pulse wave propagation time which has been corrected for errors caused by wireless communications between the electrocardiographic measuring unit and the plethysmographic measuring unit is determined, and a cardiac output is determined on the basis of the determined pulse wave propagation time.

Description

[Name of invention determined by ISA based on Rule 37.2] Cardiac output measuring device and cardiac output measuring method

The present invention relates to a cardiac output measuring device and a cardiac output measuring method for measuring cardiac output.

The cardiac output (volume per minute, CO, Cardiac Output; ml / min) is the amount of blood pumped from the heart in one minute, and therefore, in principle, the volume of one stroke (1 It is a value obtained by multiplying the stroke volume, SV, Stroke Volume) by the heart rate (BPM, Beats Par Minute) (CO = SV × BPM). Since this cardiac output is a scale that indicates the quality of the heart's pump function, it is important when, for example, so-called circulatory management is performed on patients with cardiovascular disease, postoperative patients, and the like. From the viewpoint of this circulation management, the cardiac output is preferably measured continuously and continuously as much as possible. Such cardiac output is usually measured by a thermodilution method using a thermodilution catheter. However, this measurement method is invasive and is not preferable in terms of continuously monitoring (monitoring) cardiac output. For this reason, in recent years, noninvasive techniques for measuring cardiac output, which can obtain results highly correlated with the measurement results obtained by the thermodilution method, have been researched and developed.

For example, there is a technique disclosed in Patent Document 1. The blood volume measuring device disclosed in Patent Document 1 is a blood volume measuring device that calculates a cardiac output (CO) from a pulse wave propagation time, and is a respiratory that measures respiratory changes in at least two types of parameters. Gender variation measuring means, pulse wave propagation time measuring means for measuring a pulse wave propagation time (PWTT) in a respiratory cycle, heart rate calculating means for measuring and calculating a heart rate (HR) within a predetermined time, and at least And a cardiac output calculation means for calculating cardiac output (CO) using respiratory fluctuations in two types of parameters, the pulse wave propagation time, and the heart rate. More specifically, the technique disclosed in Patent Literature 1 calculates and estimates the cardiac output CO from the following equation A.
CO = K × (α × PWTT + β) × HR (A)
Here, K is a proportionality coefficient between the pulse pressure PP (Pulse Pressure) and the stroke volume SV in the case of following the Windkessel model (SV = K × PP), and PWTT ( Pulse Wave Transit Time (pulse wave transit time) is a pulse wave propagation time that is an arrival time from the R wave of the electrocardiogram (electrocardiogram waveform) to the deleted SpO ₂ pulse wave, and HR (Heart Rate) is a heart rate. Α and β are coefficients specific to the patient that are experimentally obtained.

In the blood volume measuring device disclosed in Patent Document 1, an R wave of an electrocardiogram and a peripheral pulse wave are detected by a pulse wave propagation time detection device. This pulse wave propagation time detection device includes a time interval detection reference point measuring means constituted by electrodes attached to the chest of a patient, and this time interval detection reference point measurement means determines the R wave generation time point of an electrocardiogram as a time interval. Measure as a reference point. The pulse propagation time detection device is also provided with a photoelectric pulse wave detection sensor that is attached to the peripheral part of a patient such as a finger and obtains a pulse wave propagation time by measuring, for example, blood oxygen saturation (SpO ₂ ). These time interval detection reference point measuring means and the photoelectric pulse wave sensor are electrically connected to a measurement data transmitter by wire, and the data measured by the electrodes and the data measured by the photoelectric pulse wave detection sensor are The measurement data transmitter wirelessly transmits the signal to the biological signal monitor apparatus body. The pulse wave propagation time (PWTT) is determined by the pulse wave propagation time measuring means in the body of the biological signal monitoring device, the reference point (R wave generation time) by the time interval detection reference point measuring means, and the photoelectric pulse wave detection sensor. Is measured based on the peripheral waveform.

Here, as described above, the cardiac output is preferably continuously and continuously monitored as described above. However, when wiring is provided between the cardiac output measuring device and the patient, The wiring is an obstacle to the patient and restricts the patient's free behavior. In the blood volume measurement device disclosed in Patent Document 1, the time interval detection reference point measurement means (electrode), the photoelectric pulse wave detection sensor, and the pulse wave propagation time measurement means of the biological signal monitor device main body are: The measurement data transmitter is connected to be communicable wirelessly, and the problem due to the wiring is solved between them. However, the time interval detection reference point measurement means (electrode), the photoelectric pulse wave detection sensor, and the transmission data transmitter are connected by wire, and there is room for improvement. For this reason, for example, as disclosed in Patent Document 2, it is conceivable to individually mount wireless devices (individual wireless transceivers).

Patent Document 2 discloses a plurality of individually programmable radio transceivers, each associated with a patch electrode for use in a medical monitor, and environment settings for the plurality of programmable individual radio transceivers. A base unit including a wireless transceiver for transmitting and receiving messages including instructions to and from the plurality of individually programmable radio transceivers, wherein the base unit is configured to be remotely programmed to have a plurality of individual radios. Transmits the overall time base signal for synchronizing the transmission timing of the signal acquired by the transceiver to the base unit for individual time frames in a single frequency channel to a plurality of remotely programmable individual radio transceivers The base unit Further includes a wireless biopotential signal acquisition system that includes an interface to a monitor device, whereby a signal acquired for display can be transmitted from the base unit to the monitor device. It is disclosed.

By the way, the pulse wave propagation time PWTT is a time difference when the pulse wave generated by the heart beat is measured at a plurality of points in the body and reaches a plurality of points in the body. It is the time to reach the periphery such as limbs. More specifically, in one example, the pulse wave propagation time PWTT is measured as the time from the time when the R wave is generated in the electrocardiogram to the time when the corresponding waveform appears in the erased pulse wave. For this reason, the electrocardiogram measurement unit (electrocardiograph) that measures the electrocardiogram and the pulse wave measurement unit (pulse wave meter) that measures the peripheral pulse wave need to synchronize the time, that is, synchronize. In Patent Document 1, the time interval detection reference point measurement means (electrode) and the photoelectric pulse wave detection sensor are connected to the transmission data transmitter by wire, so that each one signal (for example, a trigger signal) is used. The timer can be reset and the time can be easily adjusted (synchronized). However, in order to solve the problem of the wiring, it is difficult to perform time adjustment (synchronization) with the one signal when wirelessly used. In this regard, in Patent Document 2, the base unit transmits the whole time basic signal to the plurality of individual radio transceivers. When the technique disclosed in Patent Document 2 is used in conjunction with the wireless communication, such a system is necessary and complicated.

On the other hand, even if the time can be synchronized (synchronized) among the individual, the electrocardiogram measurement unit (electrocardiograph) has a processing time for processing the wireless communication signal when actually performing the wireless communication. Take it. Similarly, the pulse wave measurement unit (pulse wave meter) also takes a processing time for processing a wireless communication signal when actually performing wireless communication. Furthermore, it takes a transmission time required for the wireless communication signal to propagate through space. For this reason, when it is wireless, the pulse wave propagation time is simply measured from the pulse wave measurement time detected by the pulse wave measurement unit with the detection time point of the R wave detected by the electrocardiography measurement unit as a reference point, as in Patent Document 1. When PWTT is calculated, this calculation result includes at least an error (time lag) due to processing time and transmission time of wireless communication. In particular, since the pulse wave propagation time PWTT is generally a short time of several milliseconds (several milliseconds) to several tens of milliseconds (tens of milliseconds), the error cannot be ignored in the pulse wave propagation time PWTT.

JP 2014-87484 A Special table 2004-500217 gazette

The present invention has been made in view of the above circumstances, and its purpose is to reduce the error caused by wireless communication and measure the cardiac output more accurately even if it is wireless. It is to provide an output measuring device and a cardiac output measuring method.

In the cardiac output measuring device and the cardiac output measuring method according to the present invention, the electrocardiogram measurement unit and the pulse wave measurement unit are separate and connected to each other so as to be capable of wireless communication. Based on the first measurement result relating to the electrocardiogram measured by the electrocardiogram measurement unit and the second measurement result relating to the pulse wave measured by the pulse wave measurement unit, wireless communication between the electrocardiogram measurement unit and the pulse wave measurement unit is performed. The pulse wave propagation time in which the error caused by the correction is corrected is obtained, and the cardiac output is obtained based on the obtained pulse wave propagation time. For this reason, the cardiac output measuring device and the cardiac output measuring method according to the present invention can measure the cardiac output more accurately by reducing the error caused by the wireless communication even if it is wireless. .

The above and other objects, features and advantages of the present invention will become apparent from the following detailed description and the accompanying drawings.

It is a block diagram which shows the structure of the cardiac output measuring apparatus in embodiment. It is a flowchart which shows the operation | movement of the error (correction value) measurement in the cardiac output measuring apparatus of embodiment. It is a sequence diagram which shows the operation | movement of the error (correction value) measurement in the cardiac output measuring apparatus of embodiment. It is a flowchart which shows operation | movement of the 1st aspect of the cardiac output measurement in the cardiac output measuring apparatus of embodiment. It is a figure for demonstrating the pulse wave propagation time in the case of becoming wireless. It is a flowchart which shows the operation | movement of the 2nd aspect of the cardiac output measurement in the cardiac output measuring apparatus of embodiment.

Hereinafter, an embodiment according to the present invention will be described with reference to the drawings. In addition, the structure which attached | subjected the same code | symbol in each figure shows that it is the same structure, The description is abbreviate | omitted suitably. In this specification, when referring generically, it shows with the reference symbol which abbreviate | omitted the suffix, and when referring to an individual structure, it shows with the reference symbol which attached the suffix.

The cardiac output measuring device according to the embodiment includes an electrocardiogram measurement unit that measures an electrocardiogram, and is connected to the electrocardiogram measurement unit so as to be wirelessly communicable and wirelessly communicated with the electrocardiogram measurement unit A pulse wave measurement unit that measures a pulse wave of a living body related to the predetermined communication signal, a first measurement result related to the electrocardiogram measured by the electrocardiogram measurement unit, and the pulse wave measured by the pulse wave measurement unit Based on the second measurement result, a pulse wave propagation time in which an error caused by wireless communication between the electrocardiogram measurement unit and the pulse wave measurement unit is corrected is obtained, and the obtained pulse wave propagation time is obtained. And a cardiac output calculation unit for obtaining a cardiac output based on the cardiac output. Each of the electrocardiogram measurement unit, the pulse wave measurement unit, and the cardiac output calculation unit in such a cardiac output measuring device is connected to each other so as to be capable of wireless communication, and necessary information can be exchanged with each other by wireless communication. It may be configured by a physically separated individual device (unit), or the cardiac output calculation unit is integrated with one of the electrocardiogram measurement unit and the pulse wave measurement unit. Good. Here, as an example, a case where the cardiac output calculation unit is integrated with the pulse wave measurement unit will be described below. Of course, the cardiac output calculation unit may be integrated with the electrocardiogram measurement unit, and in this case, the description can be made in the same manner as described below.

First, the configuration of the cardiac output measuring device in one embodiment will be described. FIG. 1 is a block diagram illustrating a configuration of a cardiac output measuring device according to an embodiment. The cardiac output measuring device M in the present embodiment shown in FIG. 1 includes an electrocardiogram measuring unit 1 and a pulse wave measuring unit 2.

The electrocardiogram measurement unit 1 is capable of wireless communication and measures an electrocardiogram (ECG). The electrocardiogram measurement unit 1 is, for example, an electrocardiograph equipped with a wireless communication function for transmitting and receiving communication signals wirelessly. More specifically, the electrocardiogram measurement unit 1 includes an electrode (electrocardiogram electrode) 11, a first control processing unit 12, and a first wireless communication unit 13.

The electrode 11 is a plurality of two or more electrodes for detecting a weak current (active current) flowing through the living body in association with the pulsation of the heart in order to generate an electrocardiogram. Various methods of recording an electrocardiogram are known, and the electrode 11 is configured according to the recording method. For example, in a 12-lead ECG, the electrode 11 is composed of four limb leads attached to the limbs and six chest leads (V1 to V6) attached to the chest. Further, for example, in an electrocardiogram monitor (for example, a Holter electrocardiogram), the electrode 11 is composed of a small number of 3 to 5. In the present embodiment, the pulse wave propagation time PWTT is obtained based on the detection timing at which a predetermined feature point in the electrocardiogram is detected. Therefore, the electrode 11 preferably includes an electrode suitable for detection of the predetermined feature point. . In the present embodiment, it is only necessary to measure the R wave, and therefore, a location where the R wave can be detected with a relatively small burden on the patient is desirable. The electrocardiogram measurement is, for example, measurement on the chest (V1-V6 lead), measurement of lead I, lead II, measurement between the finger and the arm on the opposite side of the finger. May be.

The first wireless communication unit 13 is connected to the first control processing unit 12, and is connected to an external device (for example, a pulse wave measurement unit 2 including a cardiac output calculation unit) according to the control of the first control processing unit 12. It is an electric circuit for performing wireless communication. The first wireless communication unit 13 is, for example, a wireless communication interface circuit using the Bluetooth (registered trademark) standard, a wireless communication interface circuit that performs infrared communication such as an IrDA (Infrared Data Association) standard, or the like.

The first control processing unit 12 controls each part of the electrocardiogram measurement unit 1 in the cardiac output measuring device M according to the function of each part, measures an electrocardiogram, and generates a first measurement result related to the electrocardiogram. Is. The first measurement result is, for example, a detection timing representing a detection timing at which a predetermined feature point in an electrocardiogram (for example, peak P wave, R wave and T wave, bottom Q wave and S wave) is detected. For example, it may be electrocardiogram information representing the electrocardiogram itself. In the present embodiment, from the viewpoint of being relatively easy to detect from an electrocardiogram, the predetermined feature point is an R wave, and the first measurement result is an R wave detection indicating an R wave detection timing at which the R wave of the electrocardiogram is detected. Timing information (peak information). The first control processing unit 12 is, for example, a CPU (Central Processing Unit), a ROM (Read Only Memory) or an EEPROM (Electrically Erasable Programmable) that stores various programs executed by the CPU and data necessary for the execution in advance. It is composed of a nonvolatile memory element such as Read Only Memory), a volatile memory element such as a RAM (Random Access Memory) serving as a so-called working memory of the CPU, and a microcomputer including peripheral circuits thereof. The first control processing unit 12 functionally includes a first control unit 121, an electrocardiogram processing unit 122, a first timer 123, and a first timer control unit 124 by executing a program.

The first control unit 121 controls each unit of the electrocardiogram measurement unit 1 according to the function of each unit in order to obtain an electrocardiogram.

The electrocardiogram processing unit 122 generates electrocardiogram data for the output of the electrode 11 by a known conventional process, and generates a first measurement result related to the electrocardiogram.

The first timer 123 is for timing.

The first timer control unit 124 resets the first timer 123 at the first timing to start the transmission process for transmitting the first measurement result, starts time measurement, and returns a response to the transmission of the first measurement result. The first elapsed time of the first timer 123 is acquired at the fourth timing when the reception process for reception is completed.

In the operation of the first mode for measuring the cardiac output described later, the first control processing unit 12 further detects a predetermined feature point from the electrocardiogram generated and measured by the electrocardiogram processing unit 122, This detection result is transmitted to the pulse wave measurement unit 2. On the other hand, in the operation of the second mode for measuring the cardiac output described later, the first control processing unit 12 further executes a synchronization mode described later.

The pulse wave measurement unit 2 is configured separately from the electrocardiogram measurement unit 1 and is capable of wireless communication. For example, a pulse wave of a living body related to a predetermined communication signal wirelessly communicated between one electrocardiogram measurement unit, for example, erasure It measures the pulse wave. The predetermined communication signal may be, for example, a detection timing signal including the detection timing information (for example, an R wave detection timing signal including R wave detection timing information), and the pulse wave measurement unit 2 may detect the detection timing signal. Using the reception as a trigger, the peripheral pulse wave is measured as a peripheral pulse wave related to the predetermined communication signal. For example, as described later, the predetermined communication signal may be a synchronization signal including synchronization information for synchronizing (time adjustment) the electrocardiogram measurement unit 1 and the pulse wave measurement unit 2 with each other. The measurement unit 2 measures the peripheral pulse wave as a peripheral pulse wave related to the predetermined communication signal in synchronization with the electrocardiogram measurement unit 1 (at the same time). The pulse wave measurement unit 2 is, for example, a photoelectric pulse wave meter that measures a pulse wave by a photoelectric method, which is equipped with a wireless communication function for transmitting and receiving communication signals wirelessly. More specifically, the pulse wave measurement unit 2 includes a second control processing unit 21, a second wireless communication unit 22, an irradiation unit 23, a light receiving unit 24, an input unit 25, and an output unit 26. .

The second wireless communication unit 22 is connected to the second control processing unit 21 and performs wireless communication with an external device (for example, the electrocardiogram measurement unit 1) according to the control of the second control processing unit 21. It is an electric circuit. The second wireless communication unit 22 is, for example, a wireless communication interface circuit using the Bluetooth (registered trademark) standard, a wireless communication interface circuit that performs infrared communication such as the IrDA standard, or the like.

The first and second wireless communication units 13 and 22 are configured according to the same communication standard so that they can communicate with each other. In the present embodiment, the first and second wireless communication units 13 and 22 are further formed with the same hardware configuration. More specifically, the first and second wireless communication units 13 and 22 have the same circuit configuration (the circuit diagrams are the same). Preferably, in the first and second wireless communication units 13 and 22, each circuit component is composed of the same type of components. In other words, in general, the same circuit can be assembled regardless of whether the electric circuit is an individual component or an integrated circuit component (IC chip), but preferably, the electric circuit is individually separated by the electric circuit of the first wireless communication unit 13. A circuit in which an individual part is used in the part of the circuit in the second wireless communication unit 22 in an area on the circuit where the part is used, and an integrated circuit part is used in the electric circuit of the first wireless communication unit 13 In the upper part, the second wireless communication unit 22 also uses an integrated circuit component in the part on the circuit. Therefore, for example, products of the same model (same product number) are preferably used for the first and second wireless communication units 13 and 22, for example.

The irradiation unit 23 is a circuit that is connected to the second control processing unit 21 and emits measurement light having a predetermined wavelength in accordance with the control of the second control processing unit 21. The light receiving unit 24 is a circuit that is connected to the second control processing unit 21, receives detection light, and outputs a light reception result to the second control processing unit 21. The detection light is obtained by allowing the measurement light to pass through a part of the living body to be measured, such as a finger, or by reflecting the measurement light from a part of the living body (in this example, the finger). For this reason, the irradiation unit 23 and the light receiving unit 24 are appropriately arranged so as to be able to use transmitted detection light (for example, facing and spaced apart), or appropriately arranged so that reflected detection light can be used. They are arranged in a relationship (for example, adjacent juxtaposition). In the cardiac output measuring device M according to the present embodiment, the irradiation unit 23 and the light receiving unit 24 are respectively arranged to face each other with a predetermined interval so that transmission detection light can be used. Placement). The measurement light is light having a wavelength capable of detecting a peripheral pulse wave, such as red light or infrared light. For example, the irradiation unit 23 includes an irradiation optical system, for example, a light source such as a light emitting diode (LED) and its peripheral circuits such as a drive circuit, and the light receiving unit 24 includes a light receiving optical system such as a photoelectric conversion element such as a silicon photodiode and the like. For example, it includes a peripheral circuit such as a current-voltage conversion circuit. Thus, the irradiation unit 23 and the light receiving unit 24 irradiate a part of the living body with predetermined measurement light, and obtain predetermined biological information from the detection light that comes from the part of the living body based on the measurement light. Therefore, an irradiation light receiving unit that receives light is configured.

The input unit 25 is connected to the second control processing unit 21 and is a device that inputs various commands such as a command instructing measurement start to the cardiac output measuring device M (pulse wave measuring unit 2). One or a plurality of input switches assigned a predetermined function. It should be noted that the input unit 25 can input various data necessary for measuring, for example, input of an identifier in the subject to be measured, to the cardiac output measuring device M (pulse wave measuring unit 2) as necessary. It may be configured. The output unit 26 is connected to the second control processing unit 21 and, according to control of the second control processing unit 21, commands input from the input unit 25 and each result measured by the cardiac output measuring device M. For example, a display device such as a CRT display, LCD, and organic EL display.

Note that a touch panel may be configured by the input unit 25 and the output unit 26. In the case of configuring this touch panel, the input unit 25 is a position input device that detects and inputs an operation position such as a resistive film method or a capacitance method, and the output unit 26 is a display device. In the touch panel, a position input device is provided on the display surface of the display device, one or a plurality of input content candidates that can be input to the display device are displayed, and the user touches the display position where the input content to be input is displayed. The position is detected by the position input device, and the display content displayed at the detected position is input to the cardiac output measuring device M (pulse wave measuring unit 2) as the operation input content of the user. In such a touch panel, since the user can easily understand the input operation intuitively, the cardiac output measuring device M (pulse wave measuring unit 2) that is easy for the user to handle is provided.

The second control processing unit 21 controls each part of the pulse wave measuring unit 2 in the cardiac output measuring device M according to the function of each part, measures the pulse wave, and obtains the second measurement result related to the pulse wave. Is to be generated. The second measurement result may be, for example, appearance timing information indicating a timing at which a waveform corresponding to a feature point of the electrocardiogram appears in the pulse wave, or may be pulse wave information indicating the pulse wave itself, for example. In the present embodiment, corresponding to the above-described example, the second measurement result is R wave appearance timing information indicating the timing at which the waveform corresponding to the R wave appears in the pulse wave.

In the cardiac output measuring device M in the present embodiment, since the cardiac output calculation unit is integrated with the pulse wave measurement unit 2, in the present embodiment, the second control processing unit 21 further includes: Based on the first measurement result received from the electrocardiogram measurement unit 1 and the second measurement result, an error caused by wireless communication is corrected to determine the cardiac output. The second control processing unit 21 is, for example, a CPU, a non-volatile storage element such as a ROM or EEPROM that stores in advance various programs executed by the CPU, data necessary for the execution, and the so-called working memory of the CPU. And a microcomputer having a volatile memory element such as a RAM and its peripheral circuits. The second control processing unit 21 is functionally executed by executing a program so that the second control unit 211, the pulse wave processing unit 212, the cardiac output calculation unit 213, the second timer 214, and the second timer A control unit 215 is configured.

The second control unit 211 controls each unit of the pulse wave measurement unit 2 according to the function of each unit in order to obtain the pulse wave and the cardiac output.

The pulse wave processing unit 212 generates pulse wave data (photoelectric pulse wave in this example) with respect to the output of the light receiving unit 24 by processing of known conventional means, and generates a second measurement result relating to the pulse wave. It is.

The second timer 214 is for timing.

The second timer control unit 215 ends the reception process for receiving the first measurement result from the electrocardiogram measurement unit 1 and starts the measurement of the peripheral pulse wave at the second timing to start the second timer 214. The second timer 214 acquires the second elapsed time of the second timer 214 at the third timing to reset and start timing, to finish the measurement of the erased pulse wave and to start the transmission process for transmitting the second measurement result Is.

The cardiac output calculation unit 213 corrects an error caused by wireless communication between the electrocardiogram measurement unit 1 and the pulse wave measurement unit 2 based on the first measurement result and the second measurement result. The obtained pulse wave propagation time PWTT is obtained, and the cardiac output is obtained based on the obtained pulse wave propagation time PWTT.

More specifically, the cardiac output calculation unit 213 functionally includes a cardiac output processing unit 2131, a correction value measurement unit 2132, and a correction value storage unit 2133.

The correction value storage unit 2133 stores a correction value used for correcting the error.

The correction value measuring unit 2132 measures the error at startup or at a predetermined time interval, stores the measured error in the correction value storage unit 2133 as the correction value, and updates the correction value. In addition, in order to obtain the correction value more accurately and obtain the cardiac output more accurately, the correction value measurement unit 2132 measures the error a plurality of times, obtains an average value of the measured plurality of errors, The obtained average value may be used as the correction value.

More specifically, in the present embodiment, the correction value measurement unit 2132 determines the error based on one round-trip wireless communication time required for one round-trip wireless communication between the electrocardiogram measurement unit 1 and the pulse wave measurement unit 2. Ask for. In one example, the correction value measurement unit 2132 performs the reply to the transmission of the first measurement result after completion of the transmission process for transmitting the second measurement result, and the first elapsed time measured by the first timer 123. The error is obtained based on the difference between the time and the second elapsed time measured by the second timer 214.

The cardiac output processing unit 2131 calculates cardiac output by correcting an error caused by wireless communication based on the first measurement result and the second measurement result. In the present embodiment, the correction value stored in the correction value storage unit 2133 is used when correcting this error.

In the operation of the first mode for measuring the cardiac output, which will be described later, the second control processing unit 21 further converts the peripheral pulse wave generated and measured by the pulse wave processing unit 212 to the predetermined feature point. The corresponding waveform is detected, and the detection result is notified to the cardiac output calculation unit 213. On the other hand, in the operation of the second mode for measuring the cardiac output, which will be described later, the second control processing unit 22 further executes a synchronization mode, which will be described later, and the electrocardiogram of the first measurement result received from the electrocardiogram measuring unit 1. And detecting the waveform corresponding to the predetermined feature point from the erased pulse wave of the second measurement result generated and measured, and calculating the cardiac output Notification to the unit 213.

Next, the operation of the cardiac output measuring device in this embodiment will be described. FIG. 2 is a flowchart showing an error (correction value) measurement operation in the cardiac output measuring device of the embodiment. FIG. 3 is a sequence diagram showing an error (correction value) measurement operation in the cardiac output measuring device of the embodiment. FIG. 4 is a flowchart illustrating the operation of the first mode of cardiac output measurement in the cardiac output measuring device of the embodiment. FIG. 5 is a diagram for explaining the pulse wave propagation time when wirelessly used. A waveform RW1 shown in the upper part of FIG. 5 shows an electrocardiogram in the electrocardiogram measurement unit 1, a waveform RW2 shown in the middle part of FIG. 5 shows an apparent electrocardiogram in the pulse wave measurement unit 2, and the lower part of FIG. A waveform RW3 shown in FIG. 5 shows a waveform of a peripheral pulse wave. The horizontal axis in FIG. 5 indicates time, and the vertical axis indicates the level in each waveform.

An operation for measuring an error caused by wireless communication will be described. First, the correction value measurement unit 2132 is activated at the time of activation (in this embodiment, since the cardiac output calculation unit is integrated with the pulse wave measurement unit 2, the pulse wave measurement unit 2 is activated), or a predetermined value An error measurement mode for measuring an error caused by wireless communication is executed at time intervals, and the start of error measurement is wirelessly communicated via the second and first wireless communication units 22 and 13. When the wireless communication signal for notifying the start of the error measurement is received, the electrocardiogram measurement unit 1 also executes the error measurement mode.

2 and 3, in the electrocardiogram measurement unit 1, the first timer control unit 124 resets the first timer 123 and causes the first timer 123 to start measuring time (S1). As a result, the elapsed time T1 of the first timer 123 is set to 0 (T1 = 0).

When the first timer 123 is reset and time measurement is started, in the electrocardiogram measurement unit 1, the first wireless communication unit 13 transmits the first measurement result according to the communication protocol, and stores the first measurement result. And wirelessly transmitted to the pulse wave measurement unit 2 (S2, ST1). Therefore, the 1st timer control part 124 resets the 1st timer 123 at the 1st timing which starts the transmission processing for transmitting the 1st measurement result, and starts time measurement. It is assumed that the first measurement result is generated by the electrocardiogram processing unit 122 based on the output of the electrode 11.

The wireless communication signal transmitted from the first wireless communication unit 13 propagates through the space and is received by the second wireless communication unit 22 of the pulse wave measurement unit 2 (ST2).

In the pulse wave measurement unit 2, the second wireless communication unit 22 receives the received wireless communication signal according to the communication protocol (ST3). In the pulse wave measurement unit 2, the correction value measurement unit 2132 repeatedly monitors the end of the reception process (No in S3), and when the reception process is completed (Yes in S3), the second timer control unit 215 includes the second timer. 214 is reset to cause the second timer 214 to start measuring time (S4). As a result, the elapsed time T2 of the second timer 214 is set to 0 (T2 = 0).

When the second timer 214 is reset and time measurement is started, the pulse wave measurement unit 2 starts measuring the peripheral pulse wave. Therefore, the second timer control unit 215 terminates the reception process for receiving the first measurement result from the electrocardiogram measurement unit 1 and starts the measurement of the peripheral pulse wave at the second timing. Reset to start timing.

The pulse wave measuring unit 2 measures the waveform of the peripheral pulse wave for a predetermined time by using the second control processing unit 21, the irradiation unit 23, and the light receiving unit 24 (ST4).

When the measurement of the deleted pulse wave is finished, the second timer control unit 215 causes the second timer 214 to finish timing, and acquires the second elapsed time T2 measured by the second timer 214 from the second timer 214. (T2 = t2).

In the pulse wave measurement unit 2, the second wireless communication unit 22 transmits the second measurement result and the second elapsed time T2 (= t2) according to the communication protocol, and stores the second measurement result and the second elapsed time T2. A wireless communication signal is generated and wirelessly transmitted to the electrocardiogram measurement unit 1 as a reply of the wireless communication signal storing the first measurement result (S6, ST5). Therefore, the correction value measuring unit 2132 of the cardiac output calculating unit 213 performs the reply to the transmission of the first measurement result after the transmission process for transmitting the second measurement result is completed.

The wireless communication signal transmitted from the second wireless communication unit 22 propagates through the space and is received by the first wireless communication unit 13 of the electrocardiogram measurement unit 1 (ST6).

In the electrocardiograph measurement unit 1, the first wireless communication unit 13 receives the received wireless communication signal according to the communication protocol (ST7). In the electrocardiogram measurement unit 1, the first control processing unit 12 repeatedly monitors the end of the reception process (No in S7), and when the reception process ends (Yes in S7), the first timer control unit 124 The timer 123 finishes timing, and the first elapsed time T1 measured by the first timer 123 is acquired from the first timer 123 (S8, T1 = t1).

The correction value measurement unit 2132 receives the notification of the first elapsed time T1 from the electrocardiogram measurement unit 1 through wireless communication, and the correction value measurement unit 2132 receives the first elapsed time T1 (= t1) and the second elapsed time T2 (= t2). ) Is calculated as a correction value X based on the difference (= | T1-T2 |) with respect to ()), stored in the correction value storage unit 2133, updated, and processed. The process ends (S9). For example, the correction value measurement unit 2132 obtains half of the difference between the first elapsed time T1 and the second elapsed time T2 (= | T1−T2 | / 2) as an error caused by the wireless communication, and obtains this The corrected error is set as a correction value X (X = | T1-T2 | / 2). Here, the transmission processing time of the first measurement result (processing time of ST1) in the electrocardiogram measurement unit 1, the transmission time of the first measurement result (processing time of ST2), and the reception of the first measurement result in the pulse wave measurement unit 2 The first processing time X1 related to wireless communication of the first measurement result that is the sum of the processing times (processing time of ST3), the transmission processing time of the second measurement result in the pulse wave measurement unit 2 (processing time of ST5), the first Second processing time related to wireless communication of the second measurement result, which is the sum of the transmission time of the two measurement results (processing time of ST6) and the reception processing time of the second measurement result in the electrocardiograph measurement unit 1 (processing time of ST7) X2 is equal to each other (X1 = X2), and each of the first processing time X1 and the second processing time X2 is equal to the correction value X (X1 = X2 = X).

Next, the operation for measuring the cardiac output (the operation of the first aspect) will be described. First, as preparation for measurement, the electrode 11 of the electrocardiogram measurement unit 1 is attached to an appropriate place such as a chest in the subject to be measured, and the irradiation unit 23 and the light receiving unit 24 of the pulse wave measurement unit 2 are provided in the subject, for example. Attached in place such as fingers. When the measurement is started, the electrocardiogram measurement unit 1 generates and measures an electrocardiogram by the electrode 11 and the electrocardiogram processing unit 122. Thereby, for example, an electrocardiogram RW1 shown in the upper part of FIG. 5 is measured. The waveform that appears on the electrocardiogram for each heartbeat is roughly composed of five waves: P wave (peak), Q wave (bottom), R wave (peak), S wave (bottom), and T wave (peak). The The electrocardiogram measurement unit 1 detects a predetermined feature point, for example, an R wave from the generated and measured electrocardiogram by the first control processing unit 12, and when the R wave is detected, the R wave detection timing information is first measured. As a result, it is transmitted to the pulse wave measuring unit 2 (S11). Since the first measurement result is R-wave detection timing information, the data capacity of the wireless communication signal storing the first measurement result can be reduced. Note that the first measurement result may be Q wave detection timing information (bottom position information) indicating the Q wave detection timing at which the Q wave immediately before the R wave is detected.

Upon receiving the first measurement result (the wireless communication signal storing the R wave detection timing information as the first measurement result), the pulse wave measurement unit 2 starts measuring the pulse wave of the subject, and the irradiation unit 23, A peripheral pulse wave is generated and measured by the light receiving unit 24 and the pulse wave processing unit 212. Thereby, for example, the pulse wave RW3 shown in the lower part of FIG. 5 is measured. Then, the pulse wave measuring unit 2 detects the waveform corresponding to the predetermined feature point, in this example, the R wave, from the erased pulse wave generated and measured, and when detecting the waveform corresponding to the R wave, The R wave appearance timing information is notified to the cardiac output calculation unit 213 as the second measurement result. The cardiac output processing unit 2131 of the cardiac output calculating unit 213 is based on the first measurement result (in this example, R wave detection timing information) and the second measurement result (in this example, R wave appearance timing information). The pulse wave propagation time is corrected with the correction value X stored in the correction value storage unit 2133, the pulse wave propagation time PWTT thus obtained is output to the output unit 26, and the pulse wave propagation time PWTT is output to the output unit 26. (S12).

In the calculation of the pulse wave propagation time, the pulse wave propagation time PWTTf is obtained from the peripheral pulse wave measured by the pulse wave measuring unit 2 with reference to the R wave detection timing in the electrocardiogram, and the obtained pulse wave propagation time is obtained. The correction value X stored in the correction value storage unit 2133 is added to PWTTf, and the corrected true pulse wave propagation time PWTT is obtained. Here, at the timing when the first measurement result is received and the pulse wave measurement is started, the waveform of the electrocardiogram is the first measurement result transmission processing time (processing time of ST1) in the electrocardiogram measurement unit 1, and the first measurement. The time is the sum of the transmission time of the result (processing time of ST2) and the reception processing time of the first measurement result in the pulse wave measurement unit 2 (processing time of ST3), ie, the correction value X. Therefore, in the pulse wave measuring unit 2, the waveform RW2 of the electrocardiogram is shifted by the correction value X from the waveform RW1 of the true electrocardiogram (upper part of FIG. 5) (apparent electrocardiogram) as shown in the middle part of FIG. It becomes. For this reason, the pulse wave propagation time PWTTf (PWTTf) before correction obtained by using the R wave appearance timing obtained by detecting the predetermined feature point, in this example, the waveform corresponding to the R wave, from the erased pulse wave in the process S12 described above. The apparent pulse wave propagation time PWTTf) is shifted from the true pulse wave propagation time PWTT by the correction value X and shortened by the correction value X, as shown in the middle and lower parts of FIG. For this reason, in the calculation of the pulse wave propagation time PWTT in the above-described process S12, the correction value X is added to the apparent pulse wave propagation time PWTTf obtained from the peripheral pulse wave measured by the pulse wave measurement unit 2 to correct the pulse wave propagation time PWTT. The true pulse wave propagation time PWTT is obtained (PWTT = PWTTf + X).

Then, the cardiac output processing unit 2131 obtains the cardiac output CO based on the obtained pulse wave propagation time PWTT, outputs the cardiac output CO to the output unit 26, causes the output unit 26 to display the cardiac output CO, The process ends (S13).

Further, the cardiac output may be obtained by the following measurement operation (operation of the second mode). FIG. 6 is a flowchart illustrating the operation of the second mode of cardiac output measurement in the cardiac output measuring device of the embodiment. First, as preparation for measurement, as described above, the electrode 11 of the electrocardiogram measurement unit 1 is attached to an appropriate place such as the chest of the subject to be measured, and the irradiation unit 23 and the light receiving unit 24 of the pulse wave measurement unit 2 are connected. For example, it is attached to an appropriate place such as a finger in the subject. When the measurement is started, each of the electrocardiogram measurement unit 1 and the pulse wave measurement unit 2 executes a synchronization mode for synchronizing (time adjustment) with each other. More specifically, for example, the pulse wave measurement unit 2 sends a synchronization signal including synchronization information for synchronizing (time adjustment) the ECG measurement unit 1 and the pulse wave measurement unit 2 to the ECG measurement unit 1. Send. For example, the pulse wave measurement unit 2 starts measuring peripheral pulse waves with the transmission of the synchronization signal. When the synchronization signal is received from the pulse wave measurement unit 2, the electrocardiogram measurement unit 1 also starts measuring an electrocardiogram. As a result, each of the pulse wave measurement unit 2 and the electrocardiogram measurement unit 1 starts measurement with a deviation of the correction value X. Further, for example, the pulse wave processing unit 212 of the pulse wave measuring unit 2 resets a timer (pulse wave timer, pulse wave clock unit) used in pulse wave measurement with the transmission of the synchronization signal. When the synchronization signal is received from the pulse wave measurement unit 2, the electrocardiogram processing unit 122 of the electrocardiogram measurement unit 1 also resets timers (electrocardiogram timer and electrocardiogram clock unit) used in the measurement of the electrocardiogram. As a result, the pulse wave timer of the pulse wave measuring unit 2 and the electrocardiogram timer of the electrocardiographic measuring unit 1 are shifted by the correction value X and start timing. Instead of resetting each timer, the pulse wave measurement unit 2 stores the current time of the pulse wave timer in a synchronization signal and transmits it to the electrocardiogram measurement unit 1, and the electrocardiogram measurement unit 1 The electrocardiogram timer may be set to the current time of the pulse wave timer of the pulse wave measurement unit 2. Further, in the above description, the pulse wave measurement unit 2 transmits the synchronization signal to the electrocardiogram measurement unit 1, but conversely, the electrocardiogram measurement unit 1 may transmit the synchronization signal to the pulse wave measurement unit 2.

When synchronized in this way, the electrocardiogram measurement unit 1 generates and measures an electrocardiogram by the electrode 11 and the electrocardiogram processing unit 122. When measuring the electrocardiogram for a predetermined time set in advance, the electrocardiogram measurement unit 1 transmits electrocardiogram information representing the electrocardiogram itself to the pulse wave measurement unit 2 as a first measurement result (S21).

On the other hand, when the synchronization is performed, the pulse wave measurement unit 2 also generates and measures a peripheral pulse wave by the irradiation unit 23, the light receiving unit 24, and the pulse wave processing unit 212. When receiving the first measurement result (wireless communication signal storing the first measurement result), the pulse wave measurement unit 2 uses the cardiac output processing unit 2131 of the cardiac output calculation unit 213 to receive the received first measurement. The predetermined feature point, for example, R wave is detected from the electrocardiogram of the result, and the waveform corresponding to the predetermined feature point, in this example, R wave, from the peripheral pulse wave of the second measurement result generated and measured. Is detected. The pulse wave measurement unit 2 uses the cardiac output processing unit 2131 to correct the pulse wave propagation time with the correction value X stored in the correction value storage unit 2133 based on the R wave detection timing and the R wave appearance timing. The pulse wave propagation time PWTT thus obtained is output to the output unit 26 and the pulse wave propagation time PWTT is displayed on the output unit 26. Then, the pulse wave measurement unit 2 shifts the measured peripheral pulse wave in terms of time by the correction value X and outputs it as the second measurement result to the output unit 26 to display the peripheral pulse wave, and the electrocardiogram is also the first one. The measurement result is output to the output unit 26 and an electrocardiogram is displayed (S22).

Then, the cardiac output processing unit 2131 obtains the cardiac output CO based on the obtained pulse wave propagation time PWTT, outputs the cardiac output CO to the output unit 26, causes the output unit 26 to display the cardiac output CO, The process ends (S23).

As described above, in the cardiac output measuring device M and the cardiac output measuring method implemented in this embodiment, the electrocardiogram measuring unit 1 and the pulse wave measuring unit 2 are physically separated from each other. Each of the electrocardiogram measurement unit 1 and the pulse wave measurement unit 2 is connected to each other so as to be capable of wireless communication. Then, the cardiac output calculation unit 213 obtains a pulse wave propagation time PWTT in which an error caused by wireless communication is corrected. For this reason, even if such a cardiac output measuring device M and a cardiac output measuring method mounted thereon are wireless, they are caused by wireless communication such as an error due to processing time and transmission time of wireless communication, for example. Thus, the cardiac output can be measured with higher accuracy by reducing the error generated.

The cardiac output measuring device M and the cardiac output measuring method implemented therein according to the present embodiment measure the error at startup or at a predetermined time interval, store the error in the correction value storage unit 2133, and correct the correction value. Update X. For this reason, the cardiac output measuring device M and the cardiac output measuring method implemented therein according to the present embodiment measure the error at the time of activation and update the correction value X. An error according to each device state and communication state of the electric measurement unit 1 and the pulse wave measurement unit 2 can be measured, and the pulse wave propagation time PWTTf can be corrected in consideration of each device state and communication state. In addition, the cardiac output measuring device M and the cardiac output measuring method implemented in the embodiment according to the present embodiment measure the error at a predetermined time interval and update the correction value X, for example, It is possible to measure an error according to the secular change in the electric measuring unit 1 and the pulse wave measuring unit 2 and the change in the communication state during measurement, and to correct the pulse wave propagation time PWTTf in consideration of the secular change and the change in the communication state. . Therefore, the cardiac output measuring device M and the cardiac output measuring method implemented therein can measure the cardiac output with higher accuracy.

In the cardiac output measuring device M in the present embodiment, the cardiac output calculating unit 213 is integrated with the pulse wave measuring unit 2. For this reason, the cardiac output measuring device M in the present embodiment can be made compact, and the electrical circuit for performing wireless communication in the cardiac output calculating unit 213 is the second in the pulse wave measuring unit 2. The wireless communication unit 22 can be shared (shared).

In the M and the cardiac output measurement method implemented in this embodiment, the first and second wireless communication units 13 and 22 have the same hardware configuration. The first processing time required for the first wireless communication unit 13 to process the signal and the second processing time required for the second wireless communication unit 22 to process the wireless communication signal in the pulse wave measurement unit 2 are equivalent. Can be considered. For this reason, the cardiac output measuring device M and the cardiac output measuring method implemented in the embodiment can determine the correction value X by calculating the error based on one round-trip wireless communication time. it can.

In the cardiac output measuring device M and the cardiac output measuring method implemented in this embodiment, the electrocardiogram measurement unit 1 transmits and transmits the first measurement result, and the first measurement result is transmitted to the pulse. The wave measurement unit 2 performs reception processing, the pulse wave measurement unit 2 measures the pulse wave to acquire a second measurement result, and the pulse wave measurement unit 2 performs transmission processing and transmits the second measurement result. The electrocardiogram measurement unit 1 receives the two measurement results. In such a sequence (procedure), the difference between the first elapsed time T1 and the second elapsed time T2 is obtained, whereby the transmission processing time (ST1 processing time) of the first measurement result in the electrocardiogram measurement unit 1 is 1 measurement result transmission time (ST2 time), pulse wave measurement unit 2 first measurement result reception processing time (ST3 processing time), pulse wave measurement unit 2 second measurement result transmission processing time (ST5) Processing time), the transmission time of the second measurement result (time of ST6), and the sum of the reception processing time of the second measurement result in the electrocardiograph measurement unit 1 (processing time of ST7) are obtained. The cardiac output measuring device M and the cardiac output measuring method implemented in the cardiac output measuring device M can obtain the error caused by wireless communication. For example, since the first and second wireless communication units 13 and 22 have the same hardware configuration, as described above, the first and second processing times X1 and X2 can be regarded as having the same value. Therefore, the cardiac output calculation unit 213 obtains half of the difference between the first elapsed time T1 and the second elapsed time T2 (= | T1-T2 | / 2) as an error caused by wireless communication, The obtained error can be used as the correction value X (X = X1 = X2).

This specification discloses various modes of technology as described above, and the main technologies are summarized below.

An cardiac output measuring device according to an aspect includes an electrocardiogram measurement unit that measures an electrocardiogram, and is connected to the electrocardiogram measurement unit so as to be wirelessly communicable and wirelessly connected to the electrocardiogram measurement unit. A pulse wave measurement unit that measures a pulse wave of a living body related to a predetermined communication signal communicated, a first measurement result relating to the electrocardiogram measured by the electrocardiogram measurement unit, and the pulse wave measured by the pulse wave measurement unit On the basis of the second measurement result regarding the pulse wave propagation time obtained by correcting an error caused by wireless communication between the electrocardiogram measurement unit and the pulse wave measurement unit. And a cardiac output calculation unit for determining the cardiac output based on. In the above-described cardiac output measuring device, preferably, the measurement of the pulse wave of the living body is performed at the periphery.

Such a cardiac output measuring device is composed of individual devices (units) in which the electrocardiogram measurement unit and the pulse wave measurement unit are physically separated from each other. They are connected to each other so that they can communicate wirelessly. The cardiac output calculation unit obtains a pulse wave propagation time in which an error caused by wireless communication is corrected. For this reason, even if such a cardiac output measuring device is wireless, for example, an error caused by wireless communication, such as an error due to processing time and transmission time of wireless communication, is reduced, and the heart rate is accurately measured. You can measure the output.

In another aspect, the above-described cardiac output measuring device further includes a correction value storage unit that stores a correction value used for correcting the error, and the cardiac output calculation unit is activated at startup or has a predetermined value. The error is measured at time intervals, the measured error is stored as the correction value in the correction value storage unit, and the pulse wave propagation time corrected for the error is obtained and stored in the correction value storage unit. Correct with the correction value.

Such a cardiac output measuring device measures the error upon activation or at a predetermined time interval, stores it in the correction value storage unit, and updates the correction value. For this reason, when the cardiac output measuring device measures the error at the time of activation and updates the correction value, each device state and communication state of the electrocardiogram measurement unit and the pulse wave measurement unit at the time of activation Can be measured, and the pulse wave propagation time can be corrected in consideration of each device state and the communication state. Such a cardiac output measuring device, for example, when measuring the error at a predetermined time interval and updating the correction value, for example, the secular change in the electrocardiogram measurement unit and the pulse wave measurement unit and the communication state during measurement It is possible to measure an error according to the change in the pulse wave, and to correct the pulse wave propagation time in consideration of the secular change and the change in the communication state. Therefore, such a cardiac output measuring device can measure the cardiac output more accurately.

In another aspect, in these above-described cardiac output measuring devices, the cardiac output calculation unit is integrated with either one of the electrocardiogram measurement unit or the pulse wave measurement unit.

Each of the electrocardiogram measurement unit, the pulse wave measurement unit, and the cardiac output calculation unit may be configured by individual devices (units) connected to each other so as to be capable of wireless communication. The cardiac output calculation unit is integrated with one of the electrocardiogram measurement unit and the pulse wave measurement unit. For this reason, such a cardiac output measuring device can be made compact, and an electrical circuit for executing wireless communication in the cardiac output calculating unit is for performing wireless communication on the one side. Can be shared (shared) with the electric circuit.

In another aspect, in the cardiac output measuring device described above, a first electric circuit for executing the wireless communication in the electrocardiogram measurement unit, and for executing the wireless communication in the pulse wave measurement unit The second electrical circuit has the same hardware configuration, and the cardiac output calculation unit is required to perform one round-trip wireless communication time required for one round-trip wireless communication between the electrocardiogram measurement unit and the pulse wave measurement unit. The error is obtained based on

In such a cardiac output measuring device, since the first and second electric circuits have the same hardware configuration, the first electric circuit required for processing the wireless communication signal in the electrocardiogram measurement unit is required. The processing time and the second processing time required in the second electric circuit for processing the wireless communication signal in the pulse wave measurement unit can be regarded as the same value. Therefore, such a cardiac output measuring device can obtain the correction value by obtaining the error based on one round-trip wireless communication time.

In another aspect, in the above-described cardiac output measuring device, the electrocardiogram measurement unit has a first timer for timing and a first timing for starting a transmission process for transmitting the first measurement result. The first timer is reset to start timing, and the first elapsed time of the first timer is acquired at the fourth timing when the reception process for receiving the reply to the transmission of the first measurement result is completed. 1 timer control unit, the pulse wave measurement unit ends the second timer for timing and the reception process for receiving the first measurement result from the electrocardiogram measurement unit, The second timer is reset at a second timing at which pulse wave measurement is started to start timing, the measurement of the pulse wave of the living body is terminated, and a transmission process for transmitting the second measurement result is started. 3rd timing A second timer control unit that acquires a second elapsed time of the second timer, wherein the cardiac output calculation unit is configured to perform the first measurement after the transmission process for transmitting the second measurement result is completed. The reply to the result transmission is performed, and the error is obtained based on the difference between the first elapsed time and the second elapsed time.

In such a cardiac output measuring device, the electrocardiogram measurement unit transmits and transmits the first measurement result, the pulse wave measurement unit receives and processes the first measurement result, and the pulse wave measurement unit transmits the pulse wave. To obtain a second measurement result, the pulse wave measurement unit transmits and transmits the second measurement result, and the electrocardiogram measurement unit receives and processes the second measurement result. In such a sequence (procedure), by obtaining the difference between the first elapsed time and the second elapsed time, the transmission processing time of the first measurement result, the transmission time of the first measurement result, and the pulse wave in the electrocardiogram measurement unit The reception processing time of the first measurement result in the measurement unit, the transmission processing time of the second measurement result in the pulse wave measurement unit, the transmission time of the second measurement result, and the reception processing time of the second measurement result in the electrocardiogram measurement unit Since the sum is obtained, such a cardiac output measuring device can obtain the error caused by the wireless communication. For example, since the first and second electric circuits have the same hardware configuration, as described above, the first and second processing times can be regarded as being equal to each other. The unit obtains half of the difference between the first elapsed time and the second elapsed time (= | first elapsed time−second elapsed time | / 2) as an error caused by the wireless communication. Can be used as the correction value.

In another aspect, in these above-described cardiac output measuring devices, the cardiac output calculating unit measures the error a plurality of times, obtains an average value of the measured plurality of errors, and calculates the obtained average A value is used as the correction value.

In such a cardiac output measuring device, the average value of a plurality of errors measured a plurality of times is used as the correction, so that the correction value can be obtained with higher accuracy. Can be requested.

In another aspect, in the above-described cardiac output measuring devices, the first measurement result is information representing a detection timing at which a predetermined feature point in the electrocardiogram is detected.

In such a cardiac output measuring device, since the first measurement result is information indicating the detection timing, the data capacity in the wireless communication signal of the first measurement result can be reduced.

The cardiac output measurement method according to another aspect includes an electrocardiogram measurement step of measuring an electrocardiogram in the electrocardiogram measurement unit, and a pulse that is separate from the electrocardiogram measurement unit and is connected to be capable of wireless communication. In the wave measurement unit, a pulse wave measurement step of measuring a pulse wave of a living body related to a predetermined communication signal wirelessly communicated with the electrocardiogram measurement unit, and a first related to the electrocardiogram measured in the electrocardiogram measurement step Based on the measurement result and the second measurement result related to the pulse wave measured in the pulse wave measurement step, an error caused by wireless communication between the electrocardiogram measurement unit and the pulse wave measurement unit is corrected. A cardiac output calculation step of obtaining a pulse wave propagation time and obtaining a cardiac output based on the obtained pulse wave propagation time.

In such a cardiac output measurement method, the cardiac output calculation step obtains a pulse wave propagation time in which an error caused by wireless communication is corrected. For this reason, each of the electrocardiogram measurement unit for executing the electrocardiogram measurement process and the pulse wave measurement unit for executing the pulse wave measurement process are configured by individual devices (units). Even when connected to each other so that wireless communication is possible, the above cardiac output measurement method reduces errors caused by wireless communication, such as errors due to processing time and transmission time of wireless communication, for example, and more accurately Can measure stroke volume.

This application is based on Japanese Patent Application No. 2014-193692 filed on September 24, 2014, the contents of which are included in the present application.

In order to express the present invention, the present invention has been properly and fully described through the embodiments with reference to the drawings. However, those skilled in the art can easily change and / or improve the above-described embodiments. It should be recognized that this is possible. Therefore, unless the modifications or improvements implemented by those skilled in the art are at a level that departs from the scope of the claims recited in the claims, the modifications or improvements are not covered by the claims. To be construed as inclusive.

According to the present invention, a cardiac output measuring device and a cardiac output measuring method can be provided.

Claims (8)

An electrocardiogram measurement unit for measuring an electrocardiogram;
A pulse wave measurement unit that is separate from the electrocardiogram measurement unit and is connected to be capable of wireless communication, and measures a pulse wave of a living body related to a predetermined communication signal wirelessly communicated with the electrocardiogram measurement unit; ,
Based on the first measurement result related to the electrocardiogram measured by the electrocardiogram measurement unit and the second measurement result related to the pulse wave measured by the pulse wave measurement unit, the electrocardiogram measurement unit and the pulse wave measurement unit A cardiac output calculation unit that calculates a pulse wave propagation time corrected for an error caused by wireless communication between the two and calculates a cardiac output based on the calculated pulse wave propagation time Cardiac output measuring device. A correction value storage unit for storing a correction value used for correcting the error;
The cardiac output calculation unit measures the error at startup or at predetermined time intervals, stores the measured error as the correction value in the correction value storage unit, and corrects the pulse wave propagation time The cardiac output measuring device according to claim 1, wherein a correction value stored in the correction value storage unit is used for correction. The cardiac output according to claim 1, wherein the cardiac output calculation unit is integrated with one of the electrocardiogram measurement unit and the pulse wave measurement unit. Quantity measuring device. The first electric circuit for executing the wireless communication in the electrocardiogram measurement unit and the second electric circuit for executing the wireless communication in the pulse wave measurement unit have the same hardware configuration,
The cardiac output calculating unit obtains the error based on one round-trip wireless communication time required for one round-trip wireless communication between the electrocardiogram measurement unit and the pulse wave measurement unit. 3. The cardiac output measuring device according to 3. The electrocardiogram measurement unit resets the first timer at a first timing for starting a time measurement and a transmission process for transmitting the first measurement result, and starts the time measurement. A first timer control unit that acquires a first elapsed time of the first timer at a fourth timing at which a reception process for receiving a response to the transmission of one measurement result is completed;
The pulse wave measurement unit finishes a second timer for timing and a reception process for receiving the first measurement result from the electrocardiogram measurement unit and starts measuring the pulse wave of the living body. The second timer is reset at the second timing to start timing, and finishes measurement of the pulse wave of the living body and starts transmission processing for transmitting the second measurement result at the third timing. A second timer control unit for acquiring the second elapsed time of
The cardiac output calculation unit performs the reply to the transmission of the first measurement result after completion of the transmission process for transmitting the second measurement result, and the first elapsed time, the second elapsed time, The cardiac output measuring device according to claim 4, wherein the error is obtained based on a difference between the cardiac output and the cardiac output. The cardiac output calculation unit measures the error a plurality of times, calculates an average value of the measured plurality of errors, and uses the calculated average value as the correction value. 6. The cardiac output measuring device according to any one of items 5. The cardiac output measuring device according to any one of claims 1 to 6, wherein the first measurement result is information indicating a detection timing at which a predetermined feature point in the electrocardiogram is detected. . An electrocardiogram measurement step of measuring an electrocardiogram in the electrocardiogram measurement unit;
In a pulse wave measurement unit that is separate from the electrocardiogram measurement unit and is connected so as to be capable of wireless communication, a pulse wave of a living body related to a predetermined communication signal wirelessly communicated with the electrocardiogram measurement unit is measured. The pulse wave measurement process to
Based on the first measurement result relating to the electrocardiogram measured in the electrocardiogram measurement step and the second measurement result relating to the pulse wave measured in the pulse wave measurement step, between the electrocardiogram measurement unit and the pulse wave measurement unit. A cardiac output calculating step of obtaining a pulse wave propagation time in which an error caused by wireless communication in the radio wave is corrected and obtaining a cardiac output based on the obtained pulse wave propagation time. How to measure stroke volume.

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