JP2007020836A - Biomedical information measuring apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize a biomedical information measuring apparatus capable of providing information related to reliability of a detection result. <P>SOLUTION: When a main switch 10 is turned on, a control part carries out a program stored in a storage part to initialize each part. Then, the control part makes a measurement part carry out operation of projecting and receiving light, and calculates oxygen saturation and a pulse rate. Then, the control part stores data of the calculated oxygen saturation and pulse rate in a storage part, and displays the data on a display part 9. Then, the control part judges whether measurement is completed or not, that is whether an index display switch 11 is turned on or not. When the index display switch is turned on, the control part carries out calculation of an ODI (Oxygen Desaturation Index) and a reliability index and displays the calculated ODI and reliability index on the display part 9. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a biological information measuring apparatus that measures biological information such as oxygen saturation of arterial blood and pulse rate.

  A device called a pulse oximeter may be used in testing for sleep apnea syndrome (SAS) or COPD (chronic obstructive pulmonary disease). This pulse oximeter has a measurement unit attached to a predetermined biological part of a subject, outputs light toward the biological part in the measurement part, and based on the amount of light transmitted or reflected through the biological part. It is configured to derive oxygen saturation in the blood.

  On the other hand, in Patent Document 1 below, a plurality of attractors corresponding to the physical condition are stored in a memory, and the attractor generated based on the collected pulse wave is compared with the attractor stored in the memory, and the physical condition is compared. And a portable health management device that displays the determination result on a display unit is disclosed.

Patent Document 2 below proposes an action recognition device that determines an action type (exercise, sleep, food and drink) based on outputs of an acceleration sensor, a pulse sensor, and a body temperature sensor, and displays the determination result on a display. Has been.
JP-A-6-217951 JP 2000-245713 A

  Conventionally, for example, when a pulse oximeter is used for a SAS test, the measurement unit is detached from a measurement site or derived by body movement or the like while measuring with the pulse oximeter during sleep. There may be errors in the oxygen saturation data, and it remains unclear how reliable the derived oxygen saturation is.

  In both Patent Documents 1 and 2, the determination result is only displayed on a predetermined display unit, and there is no description regarding a technique for providing the reliability of the determination result.

  The present invention has been made in view of the above circumstances, and an object thereof is to realize a biological information measuring apparatus capable of providing information related to the reliability of detection results.

  The invention according to claim 1 is a first derivation unit for deriving data relating to biological information based on a measurement unit that measures predetermined biological information and a biological signal derived from the biological information measured by the measurement unit. And second derivation means for deriving data indicating the reliability of the data related to the biological information, and display means capable of displaying each of the data derived by the first and second derivation means. It is the biological information measuring device characterized by this.

  According to this invention, when the predetermined biological information is measured by the measuring means, the data related to the biological information is obtained based on the biological signal derived from the biological information measured by the measuring means by the first deriving means. The second derivation means derives data indicating the reliability of the data related to the biological information. Each data derived by the first and second deriving means can be displayed by the display means. This makes it possible to provide data indicating the reliability of the data related to the derived biological information to the user of the biological information measuring apparatus.

  According to a second aspect of the present invention, in the biological information measuring apparatus according to the first aspect, an input unit for inputting an instruction to display the data indicating the reliability on the display unit, and the instruction by the input unit Is displayed, the display means includes display control means for displaying data indicating the reliability on the display means.

  According to the present invention, the input unit for inputting an instruction to display data indicating reliability on the display unit, and the index indicating the reliability on the display unit when the instruction is input by the input unit. Display control means for displaying on the display means, the user of the biological information measuring apparatus can arbitrarily set whether or not the data indicating the reliability is displayed.

  According to a third aspect of the present invention, in the biological information measuring device according to the first or second aspect, the second derivation means determines that the measured value is a normal value for the entire measurement time of the biological information. Data indicating the reliability is derived based on a ratio of time.

  According to this invention, the data indicating the reliability is derived based on the ratio of the time when the measured value is determined to be the normal value with respect to the total measurement time of the biological information. Thereby, generation of data indicating reliability can be realized.

  According to a fourth aspect of the present invention, in the biological information measuring device according to any one of the first to third aspects, the biological information is information related to oxygen saturation, and the second derivation means includes the oxygen It is characterized by deriving data indicating the reliability of the data related to the degree of saturation.

  According to the present invention, it is possible to provide data related to oxygen saturation and data indicating the reliability of the data to the user of the biological information measuring apparatus.

  According to the present invention, data indicating the reliability of the data related to the derived biometric information can be provided to the user of the biometric information measuring apparatus. Therefore, the availability of the data, the necessity for remeasurement, and the like The user can be given a room for considering the above. As a result, the subject can easily and more accurately manage the state of his / her body, and the convenience of the biological information measuring device can be improved.

  An embodiment of a pulse oximeter that is an example of a biological information measuring apparatus according to the present invention will be described. FIG. 1 is a diagram showing an external configuration of the pulse oximeter according to the first embodiment.

  As shown in FIG. 1, the pulse oximeter 1 includes a device main body 2 having a predetermined shape (elliptical shape in FIG. 1), and a measurement unit electrically (communicably connected) by the device main body 2 and the cable 3. 4. A wearing belt 8 is attached to an appropriate position of the apparatus main body 2, and the apparatus main body 2 is wound around the wrist, for example, by wrapping the wearing belt 8 around the wrist and bonding an adhesive portion such as a hook-and-loop fastener (not shown) to each other. The measurement unit 4 is a portable device that is attached to the wrist and attached to, for example, the fingertip of the subject. Hereinafter, the configuration of the measurement unit 4 will be described.

  The measurement unit 4 has a clip-like configuration that can be attached so that a measurement site (for example, a fingertip) is sandwiched by an urging force such as a spring, and the light emitting unit 5 is provided on one of the pair of clip pieces. However, the light receiving part 6 is provided on the other of the clip pieces. One end portions of the pair of clip pieces are connected by a connecting member 7, and the other end portion can be freely opened and closed.

  The light emitting unit 5 is a light source including, for example, a light emitting diode that emits red light R having a wavelength λ1 in the red region and a light emitting diode that emits infrared light IR having a wavelength λ2 in the infrared region.

  The light receiving unit 6 includes a photoelectric conversion element such as a silicon photodiode that generates a current having a magnitude corresponding to the intensity of the received light. In the present embodiment, the light receiving unit 6 includes at least a wavelength. It has sensitivity to light of λ1 and light of wavelength λ2. The light receiving unit 6 receives light having wavelengths λ1 and λ2 from the light emitting unit 5 that has passed through the living tissue LB (fingertip in FIG. 1).

  In the measurement unit 4 of the present embodiment, the red light R having the wavelength λ1 and the infrared light IR having the wavelength λ2 are emitted from the light emitting unit 5 while the fingertip of the subject who is sleeping is sandwiched between the light emitting unit 5 and the light receiving unit 6. Are alternately emitted, and the light receiving unit 6 performs a light receiving operation in synchronization with the light emitting operation of the light emitting unit 5. The light emitting operation of the light emitting unit 5 and the light receiving operation of the light receiving unit 6 are controlled by a control unit 15 which will be described later, and the time interval between the light projecting / receiving operation of the red light R and the light projecting / receiving operation of the infrared light IR. Is set to 1/150 (seconds), for example. When receiving the light, the light receiving unit 6 outputs a current signal having a magnitude corresponding to the intensity of the received light to an I / V conversion unit 12 described later in the apparatus main body 2 described later.

  Note that the pulse oximeter 1 of the present embodiment has a constant irradiation light amount at the time of measurement in order to obtain an appropriate transmitted light amount even if the thickness of the finger to be measured or the color of the skin is different. It can be adjusted within the range. The measurement unit 4 is an example of measurement means in the claims.

  The apparatus main body 2 includes a display unit 9, a main switch 10 installed on the side of the display unit 9, and an index display switch 11 installed below the main switch 10, for example, a loading chamber (not shown). It is driven by receiving power supply from a power supply source such as a battery or a dry cell.

  The display unit 9 includes a display device such as an LCD (Liquid Crystal Display), a 7-segment LED (Light Emitting Diode), an organic photoluminescence display device, or a CRT (Cathode-Ray Tube). 2), and the like. The main switch 10 is a switch for turning on / off the power of the apparatus main body 2.

  The index display switch 11 is a switch for instructing the display unit 9 to display an index to be described later.

  For example, when measuring symptoms of sleep apnea syndrome (hereinafter referred to as SAS), the pulse oximeter 1 is equipped with the apparatus main body 2 on the wrist of the subject and the measurement unit 4 on the fingertip, for example, before the start of sleep. When the main switch 10 is turned on, the oxygen saturation and the pulse rate are calculated. When the subject wakes up and the index display switch 11 is turned on, based on the data such as the oxygen saturation, A biological symptom index and a reliability index, which will be described later, are configured to be displayed on the display unit 9. The index display switch 11 is an example of input means in the claims.

  FIG. 2 is a block diagram showing an electrical configuration of the pulse oximeter 1. As shown in FIG. 2, the pulse oximeter 1 includes a measurement unit 4, a display unit 9, an I / V conversion unit 12, an A / D conversion unit 13, an input operation unit 14, and a control unit 15.

  The measurement unit 4 and the display unit 9 correspond to the measurement unit 4 and the display unit 9 shown in FIG.

  The I / V conversion unit 12 converts a current signal output from the light receiving unit 6 into a voltage signal at a predetermined cycle, and outputs the voltage signal to the A / D conversion unit 13 as a photoelectric pulse wave signal.

  The A / D conversion unit 13 converts the analog photoelectric pulse wave signal output from the I / V conversion unit 12 into a digital photoelectric pulse wave signal and outputs the digital photoelectric pulse wave signal to the control unit 15. It is.

  The input operation unit 14 includes the main switch 10 and the index display switch 11 shown in FIG. The control unit 15 includes a microprocessor, a DSP (Digital Signal Processor), and the like, and in accordance with data and programs stored in the storage unit 22, the oxygen saturation level in the arterial blood is determined from the input photoelectric pulse wave signal. Is calculated.

  In addition, the control unit 15 functionally includes a measurement control unit 16, an oxygen saturation calculation unit 17, a biological symptom index calculation unit 18, a measurement state determination unit 19, a reliability index calculation unit 20, and a display control. Unit 21 and storage unit 22.

  The measurement control unit 16 controls the operation of the light emitting unit 5 and the light receiving unit 6 of the measuring unit 4, and in this embodiment, the red light R having the wavelength λ1 and the infrared light IR having the wavelength λ2 are respectively transmitted at predetermined intervals. Then, light is emitted from the light emitting unit 5 alternately.

  The oxygen saturation calculator 17 calculates the blood oxygen saturation of the subject based on the amount of light received by the light receiver 6. Oxygen is transported by oxidation / reduction of hemoglobin in the blood. When this hemoglobin is oxidized, the absorption of red light decreases and the absorption of infrared light increases. Conversely, when it is reduced, the absorption of red light increases and the absorption of infrared light decreases. It has characteristics. The oxygen saturation calculation unit 17 uses this characteristic to measure fluctuations in the amount of transmitted light of red light and infrared light received by the light receiving unit 6, so that blood oxygen saturation (arterial blood oxygen saturation) is measured. Ask for. The oxygen saturation calculator 17 also calculates the pulse rate of the subject based on the amount of light received by the light receiver 6.

  The biological symptom index calculation unit 18 calculates an index (Oxygen Desaturation Index, hereinafter referred to as ODI) representing the number of times that the oxygen saturation has decreased below a threshold value per unit time. ODI represents, for example, a percentage (%) indicating how much the number of times the oxygen saturation has dropped below a threshold per unit time occupies the number of times the oxygen saturation is measured. In addition, when the oxygen saturation is decreased, the threshold value is a value for determining that the oxygen saturation is decreased by stopping breathing when the decrease amount is equal to or greater than the threshold, and 3 (%), 2 (%), Alternatively, it is set to a value 4 (%) lower. The oxygen saturation calculation unit 17 and the biological symptom index calculation unit 18 constitute a first derivation unit in the claims.

  The measurement state determination unit 19 determines whether the oxygen saturation calculated by the oxygen saturation calculation unit 17 is within a predetermined normal range or the variation in data used for the calculation, thereby determining the pulse oxygen. It is determined whether or not the measurement state by the meter 1 is normal.

  When measuring the SAS with the pulse oximeter 1, the measurement unit 4 leaves the measurement site, an error occurs in the oxygen saturation data derived by body movement, or the data becomes abnormal. Sometimes. Thus, when an abnormality or the like occurs in the data, the calculated oxygen saturation deviates from the normal range, so that the pulse is determined based on whether the oxygen saturation is within the normal range. It can be determined whether or not the measurement state by the oximeter 1 is normal.

  The reliability index calculation unit 20 calculates an index (hereinafter referred to as a reliability index) indicating reliability indicating how reliable the ODI data displayed on the display unit 9 is. The reliability index is an example of data indicating reliability in the scope of claims.

  In the measurement of SAS, the situation in which breathing stops depending on the orientation of the body, so if there are few symptoms that stop breathing during the 5 hour period when the measured value is determined to be normal by chance. While the evaluation at that time is underestimated, if there are many symptoms that stop breathing in the period of 5 hours, the evaluation at that time is overestimated. As the measurement time determined as normal in this way decreases, the reliability of the ODI decreases.

  For this reason, in this embodiment, the reliability index of the ODI is displayed on the display unit 9 together with the ODI. Then, the reliability index calculation unit 20 derives, as a reliability index, the ratio (percentage) of the measurement time with which the oxygen saturation data determined to be normal by the measurement state determination unit 19 to the total measurement time is obtained. . For example, if the data of a certain 3 hour period out of 8 hours of sleep is abnormal due to body movement, the data of the remaining 5 hour period judged to be normal is used, and 5 (hour) / 8 (hour ) × 100 = 63 (%) is derived as a reliability index. The reliability index calculation unit 20 is an example of a second derivation unit in the claims.

  The display control unit 21 displays the results calculated by the oxygen saturation calculation unit 17, the biological symptom index calculation unit 18, and the reliability index calculation unit 20 on the display unit 9.

  When the main switch 10 is turned on, the display control unit 21 displays the oxygen saturation calculated by the oxygen saturation calculation unit 17 on the display unit 9 until the index display switch 11 is turned on. When the display switch 11 is turned on, the result (biological symptom index and reliability index) calculated by the biological symptom index calculation unit 18 and the reliability index calculation unit 20 is displayed on the display unit 9 as shown in FIG. . FIG. 1 shows a display form in which the biological symptom index calculated by the biological symptom index calculating unit 18 and the reliability index calculated by the reliability index calculating unit 20 are displayed vertically. The display control unit 21 corresponds to display control means in the claims.

  In addition to the data and programs described above, the storage unit 22 temporarily stores the oxygen saturation measured between the time when the main switch 10 is turned on and the time when the indicator display switch 11 is turned on. Or stores data related to the pulse rate.

  FIG. 3 is a flowchart showing the measurement operation performed by the pulse oximeter 1.

  As shown in FIG. 3, when the main switch 10 is turned on (YES in step # 1), the control unit 15 executes the program stored in the storage unit 22 to measure the measurement unit 4 and the I / V conversion unit. 12, the A / D converter 13 and the storage unit 22 are initialized (step # 2). Then, the control unit 15 causes the measurement unit 4 to perform a light projecting / receiving operation (step # 3), and the control unit 15 is based on the data after each processing by the I / V conversion unit 12 and the A / D conversion unit 13. Oxygen saturation and pulse rate are calculated (step # 4). Then, the control unit 15 stores the calculated oxygen saturation and pulse rate data in the storage unit 22 (step # 5) and displays the data on the display unit 9 (step # 6).

  Then, the control unit 15 determines whether or not the measurement is finished, that is, whether or not the index display switch 11 is turned on (step # 7), and until the index display switch 11 is turned on (NO in step # 11). Steps # 3 to # 7 are repeated.

  When the index display switch 11 is turned on (YES in step # 7), the control unit 15 performs an ODI and reliability index calculation (step # 8), and displays the calculated ODI and reliability index. 9 (step # 9). In the present embodiment, it is determined whether or not the oxygen saturation stored in the storage unit 22 is normal during the process of step # 8. The determination is performed during the process of step # 5. And normal oxygen saturation data and abnormal oxygen saturation data may be distinguished from each other and stored in the storage unit 22. In addition, if the calculation of the biological symptom index and the reliability index is not performed at the end of the measurement, but is performed at a short time interval, for example, every 10 minutes, the biological symptom index and the reliability index are in a form close to real time. Can be provided to the user of the pulse oximeter 1.

  As described above, since the reliability index indicating the reliability of the ODI data is displayed on the display unit 9 in addition to the ODI of the subject, the subject and the measurer are derived by the pulse oximeter 1. You can see how reliable ODI is. As a result, for example, when analyzing the SAS of the subject using the obtained ODI, the analysis is performed using only valid ODI, or, for example, according to the reliability of the ODI, Weights can be taken into account. As a result, the subject can easily and more accurately manage his / her body condition, and the convenience of the pulse oximeter 1 can be improved.

  The present invention includes the following modifications [1] to [6] in addition to or in place of the embodiment.

  [1] In the above embodiment, the calculated ODI is displayed on the display unit 9 as it is. However, the present invention is not limited to such a display form of biological symptoms. The level at which the ODI is located may be displayed.

  For example, ODI of 0% to 100% is divided into four stages of “treatment required”, “follow-up”, “mild”, and “no problem”, and a stage corresponding to the subject's ODI is selected from them, The stage name may be displayed on the display unit 9.

  In addition, the biological symptom index displayed on the display unit 9 is not limited to ODI, and may be the lowest value of the oxygen saturation measured during the measurement period. In short, an index representing the symptom of the subject is displayed. That's fine.

  [2] In the first embodiment, the reliability index is expressed as a percentage of the ratio of the measurement time determined to be normal to the total measurement time of the measurement. However, the present invention is not limited to this, and other derivation methods may be used.

  Further, when the reliability index is displayed on the display unit 9, the derived reliability is divided into a plurality of levels, for example, “high reliability”, “medium reliability”, and “low reliability”, and the ODI of the subject. You may make it display in which step the reliability of is.

  [3] Based on the body movement of the subject, it is possible to detect whether the subject is in a sleeping state or in an awake state, so that the pulse oximeter 1 detects acceleration of the body. When the sensor is mounted, the movement of the subject's body may be detected based on the output of the acceleration sensor, and the sleep start time or the awakening time may be detected based on the detected body movement. . When the sleep start time and the awakening time are detected in this way, a more accurate sleep time can be detected. Therefore, a period in which the body is in a normal direction, a period in which abnormal data is output due to body movement, etc. Can be grasped accurately. As a result, highly accurate ODI can be derived.

  [4] In the first embodiment, a function for inputting an instruction to end measurement to the index display switch 11 and a function for inputting an instruction to calculate an ODI or a reliability index and display the calculation result on the display unit 9. However, the present invention is not limited to this mode. For example, a function for inputting a measurement end instruction is realized by another button or switch, and each time the index display switch 11 is pressed, the ODI and the reliability index are displayed. The presence or absence of calculation and display may be switched.

  Further, the reliability index is not limited to the form of displaying along with the biological symptom index such as ODI, and whether or not the reliability index is displayed by a predetermined button or switch or the like independently of the display operation of the biological symptom index. May be allowed to be indicated.

  Thereby, since calculation of ODI and a reliability parameter | index and execution of a display can be selected arbitrarily, a test subject's will can be reflected regarding the presence or absence of the calculation / display of a biological symptom parameter | index or a reliability parameter | index.

  [5] The pulse oximeter can be used not only for measurement of SAS but also for measurement of symptoms in patients with COPD (chronic obstructive pulmonary disease). In that case, the oxygen saturation is continuously measured day or night, and when the acceleration sensor is mounted as in the modified embodiment [2], the body movement of the subject is determined based on the output of the acceleration sensor. By measuring and analyzing the degree of decrease in oxygen saturation with respect to the amount of exercise, and displaying the analysis result as an index, the state management of the body by the COPD patient can be performed easily and more accurately. As a reliability index in this case, the ratio of the actual recording time to the recording time including the required exercise can be considered.

  [6] The biological information measuring device in the present case is not limited to the above-described pulse oximeter, and the detected biological information is stored in the device, and an index representing the state (symptom) of the biological body is stored from the stored biological information. The scope of application is a general apparatus that is derived and displayed, and the reliability of an index representing the derived state of a living body is also displayed as an index on such an apparatus.

It is a figure which shows the external appearance structure of the pulse oximeter which concerns on 1st Embodiment. It is a block diagram which shows the electrical structure of a pulse oximeter. It is a flowchart which shows the measurement operation | movement performed with a pulse oximeter.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Pulse oximeter 2 Apparatus main body 4 Measuring part 5 Light emission part 6 Light receiving part 9 Display part 10 Main switch 11 Index display switch 15 Control part 16 Measurement control part 17 Oxygen saturation calculating part 18 Biological symptom index calculating part 19 Measurement state determination part 20 reliability index calculation unit 21 display control unit 22 storage unit

Claims (4)

Measuring means for measuring predetermined biological information;
First derivation means for deriving data related to biological information based on biological signals derived from biological information measured by the measurement means;
Second derivation means for deriving data indicating the reliability of the data related to the biological information;
A biological information measuring apparatus comprising: display means capable of displaying each of the data derived by the first and second derivation means. An input means for inputting an instruction to display data indicating the reliability on the display means;
The biological information measuring apparatus according to claim 1, further comprising: a display control unit that causes the display unit to display data indicating the reliability on the display unit when the instruction is input by the input unit. .   The second deriving unit derives data indicating the reliability based on a ratio of a time when the measured value is determined to be a normal value with respect to a total measurement time of the biological information. The biological information measuring device according to 1 or 2. The biological information is information related to oxygen saturation,
The biological information measuring apparatus according to claim 1, wherein the second deriving unit derives data indicating reliability of the data related to the oxygen saturation.

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