WO2009133851A1 - Device for measuring oxygen saturation degree - Google Patents

Device for measuring oxygen saturation degree Download PDF

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Publication number
WO2009133851A1
WO2009133851A1 PCT/JP2009/058280 JP2009058280W WO2009133851A1 WO 2009133851 A1 WO2009133851 A1 WO 2009133851A1 JP 2009058280 W JP2009058280 W JP 2009058280W WO 2009133851 A1 WO2009133851 A1 WO 2009133851A1
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WO
WIPO (PCT)
Prior art keywords
value
oxygen saturation
spo
stability
determination
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PCT/JP2009/058280
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French (fr)
Japanese (ja)
Inventor
典浩 舘田
晃宏 鵜飼
繁 大崎
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コニカミノルタセンシング株式会社
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Publication of WO2009133851A1 publication Critical patent/WO2009133851A1/en

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    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/145—Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissue
    • A61B5/1455—Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissue using optical sensors, e.g. spectral photometrical oximeters
    • A61B5/14551—Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissue using optical sensors, e.g. spectral photometrical oximeters for measuring blood gases

Definitions

  • the present invention relates to an oxygen saturation measuring apparatus for measuring the oxygen saturation of arterial blood.
  • a pulse oximeter oxygen saturation measuring device
  • the pulse oximeter is attached to a predetermined living body part of a subject, outputs light toward the living body part, measures a change in the amount of light transmitted or reflected through the living body part as a signal, Saturation (hereinafter referred to as SpO 2 value) or the like is obtained.
  • Saturation hereinafter referred to as SpO 2 value
  • the SpO 2 value may be measured by a pulse oximeter in the same manner as body temperature measurement.
  • in-patients may be equipped with a pulse oximeter to measure the patient's SpO 2 value as a daily health check.
  • the SpO 2 value temporarily decreases abruptly just by walking. Be measured SpO 2 value in this state, SpO 2 value has changed from time to time, it is impossible to measure the correct value. Therefore, after mounting the pulse oximeter to the patient, until the SpO 2 value is stabilized, it is necessary to visually confirm the SpO 2 value displayed. In this way, the read SpO 2 value is the correct value while the SpO 2 value is stable. This operation is usually performed by a nurse or the like, but since it is confirmed visually, other operations cannot be performed during this period.
  • Patent Document 1 the SpO 2 value displayed at any time, determined the stability of the SpO 2 values, when the SpO 2 value is judged to be stable, without subsequent measurements, at that time
  • An oximeter that displays the displayed SpO 2 value as it is is described.
  • Formula 1 shown below is used for the determination of the stability of the oximeter.
  • DS is a determination value
  • W (I) is a weighting factor.
  • S (0) represents the currently displayed SpO 2 value
  • S (-1) represents the previous SpO 2 value
  • S (-2) displayed the previous two. It represents the SpO 2 value.
  • W (I) is a value determined by I.
  • the determination value DS obtained by Equation 1 indicates that the smaller the value, the less the change in the display SpO 2 value and the higher the stability. Therefore, oximeter described in Patent Document 1, the judgment value DS is equal to or smaller than the predetermined threshold value SpO 2 value is determined to be stable, and fixed displays the SpO 2 values displayed at that time.
  • the display SpO 2 value displayed on the oximeter is a value obtained by, for example, averaging a plurality of consecutive SpO 2 values (instantaneous SpO 2 values) obtained from the optical signal obtained by measurement, It differs from the value obtained by one measurement. Therefore, just because the displayed SpO 2 value does not seem to change much, there is a problem that it cannot be said that the patient's SpO 2 value is actually stable. For example, even if the instantaneous SpO 2 value is unstable, the display SpO 2 value obtained by performing arithmetic processing such as averaging the instantaneous SpO 2 value may be determined to be stable. For this reason, the oximeter described in Patent Document 1 has a problem that although the stability of the SpO 2 value is actually low, it is determined that the SpO 2 value is stable and the SpO 2 value is fixedly displayed. .
  • the present invention has been made in view of the above circumstances, and an object thereof is to provide an oxygen saturation measuring device that performs a determination of whether or not the SpO 2 value is stable by a more reliable method. It is to be.
  • the oxygen saturation measurement apparatus of the present invention includes a stability determination unit that determines the stability of oxygen saturation based on a signal component.
  • the stability determination unit evaluates the signal component, and the signal component has a predetermined evaluation. When the standard is satisfied, it is determined that the oxygen saturation is stable.
  • FIG. 1 is a diagram showing an external configuration of a pulse oximeter according to an embodiment.
  • FIG. 2 is a block diagram showing the configuration of the pulse oximeter according to the embodiment.
  • the pulse oximeter 100 includes a device main body 1 and a measuring unit 2 electrically connected to the device main body 1 via a cable 16.
  • the pulse oximeter 100 is used by being attached to a hand 300 of a subject (patient).
  • the apparatus main body 1 has a mounting belt 17, and the apparatus main body 1 is fixed to the wrist of the subject by, for example, winding the mounting belt 17 around the wrist of the subject.
  • the apparatus body 1 further includes a display unit 6 and an operation unit 8.
  • the display unit 6 is for displaying biological information such as measurement results, that is, blood oxygen saturation (SpO 2 value).
  • the operation unit 8 is, for example, a switch circuit and the like, and is used for instructing reading of measurement results and instructions for starting or ending measurement.
  • the biological information is information serving as an index representing biological information such as the SpO 2 value and pulse of the subject obtained by analyzing an electrical signal obtained from the living body by the pulse oximeter.
  • the measuring unit 2 is attached to the fingertip of the subject, for example. Specifically, it has a shape like a finger sack and is worn by being fitted to the fingertip of the subject. Although not shown in FIG. 1, measurement is performed by the light emitting unit 21 and the light receiving unit 22 installed inside the measuring unit 2 (see FIG. 2).
  • the pulse oximeter 100 includes an apparatus main body 1 and a measurement unit 2.
  • the measuring unit 2 includes a light emitting unit 21 and a light receiving unit 22, and in a state where a measurement site (for example, a fingertip) is fitted in the measuring unit 2, that is, in a measurement state, the light emitting unit 21 and the light receiving unit 22 are interposed between the fingertips. It is arranged so as to face each other. Thereby, biological information can be measured based on the transmitted light of the measurement site. In addition, biological information can also be measured based on the reflected light of the measurement site, and in this case, the light emitting unit 21 and the light receiving unit 22 are arranged adjacent to each other.
  • the light emitting unit 21 is a light source including, for example, a light emitting diode that emits red light having a wavelength in the red region and a light emitting diode that emits infrared light having a wavelength in the infrared region.
  • a light emitting diode that emits red light having a wavelength in the red region
  • a light emitting diode that emits infrared light having a wavelength in the infrared region.
  • the amount of irradiation light can be adjusted within a certain range during measurement. It is preferable to do.
  • the light receiving unit 22 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.
  • the light receiving unit 22 receives light from the light emitting unit 21 that has passed through the fingertip of the subject as the measurement site. Therefore, this photoelectric conversion element has sensitivity to red light and infrared light emitted from the light emitting unit 21.
  • the light receiving unit 22 converts optical signals of red light and infrared light into electrical signals that are biological information signals and outputs the electrical signals.
  • the biological information signal is an electrical signal that depends on the living body of the subject obtained by measurement. More specifically, the biological information can be obtained by analyzing the biological information signal.
  • the apparatus body 1 includes a control unit 4, a storage unit 5, a display unit 6, a power supply unit 7, an operation unit 8, an I / V conversion unit 31, and an A / D conversion unit 32.
  • the storage unit 5 includes a ROM (Read Only Memory) that stores a control program of the pulse oximeter 100, an EEPROM (Electrically Erasable Programmable ROM) that temporarily stores data such as arithmetic processing and control processing, and a RAM (Random Access). Memory) and flash memory.
  • ROM Read Only Memory
  • EEPROM Electrical Erasable Programmable ROM
  • RAM Random Access Memory
  • flash memory flash memory
  • the biological information signal obtained by the measurement unit 2 is analyzed by the analysis processing unit 42, and the light amount and pulse wave amplitude of each light received by the light receiving unit 22, infrared light and red color are obtained.
  • the amplitude ratio with light, the instantaneous SpO 2 value (instantaneous blood oxygen saturation), the display SpO 2 value (displayed blood oxygen saturation), and the like are stored in association with the timing information.
  • the instantaneous SpO 2 value is an SpO 2 value calculated from a biological information signal obtained by one measurement operation.
  • the display SpO 2 value is an average value or a moving average value of a plurality of instantaneous SpO 2 values calculated in a predetermined period, and is a value to be displayed on the display unit 6. Since the instantaneous SpO 2 value is the same value obtained by one measurement, when the instantaneous SpO 2 value is displayed on the display unit 6 for each measurement, the display is displayed when the instantaneous SpO 2 value slightly changes. Flicker. Therefore, it is difficult for the operator to read the displayed value.
  • the average value or the moving average value of the instantaneous SpO 2 values measured in a certain period is displayed on the display unit 6 as the display SpO 2 value.
  • the determination of the stability of the SpO binary value uses data going back for a certain period from the present, but the stored data is stored in association with the timing information in this way, so that past data can be read out. Can be easily performed.
  • the time measurement information may be time from the start of measurement or time.
  • the display unit 6 includes a display device such as an LCD (Liquid Crystal Display), a 7-segment LED (Light Emitting Diode), an organic electroluminescence display device, or a CRT (Cathode Ray Tube) display device.
  • the display unit 6 displays, for example, SpO 2 value, which is measured biological information, and information indicating that the measurement is being performed or a fixed display.
  • the display unit 6 may display lighting, blinking, characters, numbers, symbols, pictorial symbols, characters, and the like.
  • the power supply unit 7 supplies power to the pulse oximeter 100, that is, the measurement unit 2 and the apparatus main body 1. Considering the troublesomeness when the pulse oximeter 100 is mounted, it is desirable to eliminate the need for a power supply cable. Therefore, the power supply unit 7 may include a button battery, a secondary battery, and the like. In addition, it is preferable that the power supply part 7 is provided with the power supply circuit which has a power-off function which stops a power supply automatically, if a measurement is not made for a fixed time.
  • the operation unit 8 is configured with switches and buttons for operating the pulse oximeter 100. Specifically, a switch for turning on / off the power, a switch for instructing measurement start, measurement extension, and various other operations are provided. In addition, a button that can instruct to change the level of the stability determination condition, a stability determination mode in which stability determination is performed and the SpO 2 value is determined to be stable, and continuous measurement that continues measurement A switch or the like for switching the measurement mode is provided.
  • the I / V conversion unit 31 converts a current signal output from the light receiving unit 22 into a voltage signal at a predetermined cycle, and outputs the voltage signal to the A / D conversion unit 32 as a photoelectric pulse wave signal.
  • the A / D conversion unit 32 ⁇ ⁇ converts the photoelectric pulse wave signal, which is an analog biological information signal output from the I / V conversion unit 31, into a digital photoelectric pulse wave signal and outputs it to the control unit 4.
  • the control unit 4 includes various electronic components, integrated circuit components, a CPU (Central Processing Unit), and the like, and controls the operation of each unit of the pulse oximeter 100. Functionally, the measurement control unit 41, the analysis processing unit 42, A stability determination unit 43 and a display control unit 44 are provided.
  • a CPU Central Processing Unit
  • the measurement control unit 41 controls the measurement operation of biological information by the measurement unit 2 according to a predetermined measurement program. Specifically, red light and infrared light are alternately emitted from the light emitting unit 21 at each sampling period, and a photoelectric conversion signal is acquired from the light receiving unit 22 in synchronization with the light emission timing.
  • the display control unit 44 displays the display SpO 2 value and the like calculated by analyzing the biological information signal obtained by the display representing the state under measurement or the measurement by the analysis processing unit 42 in a predetermined display form. Controls the display operation to be displayed.
  • the display control unit 44 causes the display unit 6 to display the SpO 2 value fixedly.
  • the fixed display means that the currently displayed value is continuously displayed (the display is not updated), that is, the display of the displayed blood oxygen saturation is not updated. Accordingly, after being fixed display is performed actual measurement operation, even as different SpO 2 value has been calculated and thereby the displayed value, the SpO 2 value displayed on the display unit 6 does not change .
  • the fixedly displayed value is a value when the SpO 2 value is stabilized
  • the fixedly displayed value is a correct value without variation as the SpO 2 value of the subject.
  • the SpO 2 value is fixed display may be used a display SpO 2 values of arbitrary timing in the period of SpO 2 value is determined to be stable, also, SpO 2 value to be stable determination it may be using the average value of all the listed display SpO 2 values in period.
  • the analysis processing unit 42 performs predetermined data analysis based on the biological information signal obtained by the measurement unit 2, and the light amount and pulse wave amplitude of each light received by the light receiving unit 22, the infrared light and the red light. An amplitude ratio, an instantaneous SpO 2 value, and the like are obtained. Further, an average value or moving average value of instantaneous SpO 2 values in a predetermined period is calculated, and a display SpO 2 value that is a value to be displayed on the display unit 6 is obtained.
  • Oxygen is supplied to each part in the living body by being transported by blood. More specifically, oxygen is transported by oxidation and reduction of hemoglobin in 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 analysis processing unit 42 calculates the SpO 2 value using this characteristic. Specifically, first, the variation in the amount of transmitted light of red light and infrared light received by the light receiving unit 22 is measured, and the instantaneous SpO 2 value for each sampling period is calculated based on the amplitude ratio of the red light and infrared light. To do.
  • an average value or a moving average value in a predetermined range of the calculated instantaneous SpO 2 value is obtained, and this is set as a display SpO 2 value.
  • the display SpO 2 value is displayed on the display unit 6 by the display control unit 44. Note that the display SpO 2 value may be calculated every sampling cycle, or may be calculated every predetermined period, for example, every second.
  • the stability determination unit 43 sets at least one of the light amount and pulse wave amplitude of each light received by the light receiving unit 22, the amplitude ratio between infrared light and red light, the instantaneous SpO 2 value, and the display SpO 2 value. Based on this, it is determined whether the SpO 2 value is stable. Specifically, the stability determination unit 43 reads from the storage unit 5 and evaluates the current value and the data obtained by the measurement from the present to the past for a certain period of time. Specifically, the determination value is obtained by substituting the data read from the storage unit 5 into a predetermined calculation formula. The calculation formula is set so that the determination value decreases as the stability of the SpO 2 value increases. Thereby, when this determination value is below a predetermined threshold value, that is, when a predetermined evaluation criterion is satisfied, it is determined that the SpO 2 value is stable.
  • the stability determination unit 43 includes at least the light amount and pulse wave amplitude of each light received by the light receiving unit 22 that is a signal component, the amplitude ratio between infrared light and red light, and the instantaneous SpO 2 value.
  • signal stability is stability of the SpO 2 value is determined on the basis of either stable SpO 2 value is determined based on the display SpO 2 value displayed on the display section 6 that is calculated from the instantaneous SpO 2 value
  • the stability of the SpO 2 value is determined using both the display stability, which is a degree.
  • the pulse oximeter 100 according to the embodiment, the display not only stability, since determining the stability of the signal stability be used SpO 2 value, stability of more reliable SpO 2 value Degree determination can be performed.
  • the signal component for obtaining the signal stability has a plurality of parameters. Therefore, the stability determination unit 43 may evaluate all these parameters to determine the stability of the SpO 2 value, or may evaluate at least one of the parameters to determine the stability of the SpO 2 value. You may judge. A method for evaluating each parameter will be described below. Specifically, each value to be evaluated is individually evaluated, and if each value satisfies a predetermined evaluation criterion, it is determined that the SpO 2 value is stable. More specifically, a determination value is obtained, and when the value is equal to or smaller than a predetermined threshold, it is determined that the SpO 2 value is stable.
  • the determination value may be the reciprocal of the average value of the amount of transmitted light between m points (m is an integer of 1 or more) including the value measured at present. Note that m may be about 10.
  • the determination value DS 11 is expressed by Equation 2 shown below.
  • n (n is an integer of 1 or more) is the number of measurement values from the start of measurement to the present. That is, from the start of measurement, the analysis processing unit 42 has received the biological information signal n times to the present and performs analysis processing.
  • L (k) represents the amount of transmitted light in the kth measurement (m is an integer of 1 or more) from the start of measurement. It is noted that the reason why the determination value DS 11 is the reciprocal of the mean value, the case where the determination value DS 11 is small in order to the high stability of the SpO 2 values.
  • the previously determined a predetermined threshold value, determination value DS 11 is in the following cases the threshold is determined to be high stability of SpO 2 values.
  • a value obtained by the current measurement and a value obtained by the past measurement from the current time are used. Specifically, obtaining a present time, the determination value DS 11 and the value with the m while going back from the current time in the past.
  • the period during which the values used for these determinations are measured is referred to as a determination target period. That is, the measurement unit 2 performs m measurements within the determination target period, and the analysis processing unit 42 receives m pieces of biological signal information from the light receiving unit 22.
  • stability judging unit 43 obtains the determination value DS 11, may determine these the higher stability of the SpO 2 values when more than a predetermined threshold value.
  • the stability determination unit 43 can change the determination target period in accordance with the amount of transmitted light. And the stability determination part 43 should just make the determination object period short, specifically, so that the transmitted light amount is large. In the case of a pulse oximeter that receives reflected light by the light receiving unit 22, the reflected light amount may be used instead of the transmitted light amount.
  • the pulse wave amplitude is evaluated to determine the stability of the SpO 2 value.
  • the pulse wave amplitude also has a poor SN ratio (Signal to Noise Ratio) when the amplitude level is not sufficient. Therefore, the stability of the SpO 2 value can be determined using the average value of the pulse wave amplitude as well as the transmitted light amount.
  • a standard deviation may be used when evaluating the pulse wave amplitude and determining the stability of the SpO 2 value.
  • variation in the magnitude of the pulse wave amplitude may be used as the determination value.
  • the determination value DS 12 when the average value of the pulse wave amplitude is used is expressed by the following Expression 3
  • the determination value DS 13 when the standard deviation of the pulse wave amplitude is used is the following expression: It is represented by 4.
  • Equation 4 l is the same value as k.
  • a (k) and A (l) represent pulse wave amplitudes from the k-th and l-th measurements from the start of measurement. From these equations, the stability determination unit 43 may determine the determination values DS 12 and DS 13 and determine that the stability of the SpO 2 value is high when they are equal to or less than a predetermined threshold.
  • the stability determination unit 43 can change the determination target period according to the magnitude of the pulse wave amplitude. And specifically, the stability determination part 43 should just shorten a determination object period, so that a pulse wave amplitude is large.
  • the determination value DS 14 in this case is represented by Equation 5 shown below.
  • s (k) and s (l) represent instantaneous SpO 2 values obtained by the k-th and l-th measurements from the start of measurement.
  • the stability determination unit 43 may determine the determination value DS 14 and determine that the stability of the SpO 2 value is high when the value is equal to or less than a predetermined threshold.
  • the stability determination unit 43 may determine that the stability of the SpO 2 value is high when the determination value is equal to or less than a predetermined threshold.
  • the threshold value may be about 0.5% of the instantaneous SpO 2 value.
  • the stability determination unit 43 obtains an average value of instantaneous SpO 2 values within a predetermined period, and determines an abnormal value if the value deviates by about ⁇ 5 to 20% or more from the average value, and calculates a determination value. Should not be used.
  • the stability determination unit 43 performs approximation of the linear line using the least square method for each instantaneous SpO 2 value (for m points) within the determination target period, and determines the absolute value of the slope in the linear approximate line. It may be obtained as a value.
  • the determination value calculated in this way indicates a continuous change in the instantaneous SpO 2 value. That is, when the instantaneous SpO 2 value continuously decreases or increases, this determination value becomes relatively large. In such a case, the SpO 2 value is not stable, and the smaller the slope of the approximate line, the higher the stability of the SpO 2 value. Therefore, the stability determination unit 43 may determine that the SpO 2 value is stable when the calculated determination value is equal to or less than a predetermined threshold value. Note that, in the determination based on the instantaneous SpO 2 value, the stability determination unit 43 may use the equation 1 described in Patent Document 1 described above.
  • Stability judging unit 43 in the judgment of the stability of the SpO 2 value according to the instantaneous SpO 2 values, determined the determination value, it is determined that the SpO 2 value when their value is less than the predetermined threshold value is stable Good.
  • the stability determination unit 43 may determine that the SpO 2 value is not stable when the abnormal value is included in a predetermined ratio or more within the determination target period.
  • the abnormal value may be a value that deviates by about ⁇ 5 to 20% or more from the average value of the instantaneous SpO 2 values within a predetermined period, as described above.
  • the instantaneous SpO 2 values since those determined by the amplitude ratio of the infrared light and red light, in the calculation of the decision value using the instantaneous SpO 2 value, infrared light instead of the instantaneous SpO 2 value Alternatively, the amplitude ratio of red light may be used, and a similar determination value can be obtained. Therefore, the above description, in the determination using the instantaneous SpO 2 values may be used amplitude ratio of the infrared light and red light, instead of the instantaneous SpO 2 value. Specifically, the stability determination unit 43 may determine that the SpO 2 value is stable when the standard deviation of the amplitude ratio of infrared light and red light is equal to or less than a predetermined threshold value.
  • the stability determination unit 43 has high stability of the SpO 2 value when the determination value is equal to or less than a predetermined threshold value. May be determined.
  • the threshold value may be about 0.5% of the amplitude ratio of infrared light and red light.
  • the stability determination unit 43 obtains an average value of the amplitude ratio of infrared light and red light within a predetermined period, and determines that it is an abnormal value if the value is more than about ⁇ 5 to 20% or more from the average value. It is sufficient not to use it for calculation of the judgment value.
  • the stability determination unit 43 may determine that the stability of the SpO 2 value is high when the determination value is equal to or less than a predetermined threshold value.
  • the stability determination unit 43 may determine that the SpO 2 value is not stable when the abnormal value is included in a predetermined ratio or more in the determination target period.
  • the abnormal value may be a value that deviates by about ⁇ 5 to 20% or more from the average value of the amplitude ratio of infrared light and red light within a predetermined period.
  • Stability judging unit 43 when determining the stability of the SpO 2 values by the display SpO 2 values, as in the formula 4 or formula 5 may be determined using the standard deviation. Specifically, the stability determination unit 43 replaces s (k) and s (l) indicating the value of the pulse wave amplitude in Equation 5 with the display SpO 2 values obtained by the k-th and l-th measurements from the start of measurement. And the determination value may be obtained.
  • the Stability judging unit 43 Further, as with the determination of the stability of the SpO 2 value according to the instantaneous SpO 2 values, the difference between the maximum value and the minimum value among the measured values within the determination period of these values It is good also as a judgment value.
  • the abnormal value should be deleted from the maximum value and the minimum value. For example, a value that deviates by about ⁇ 5 to 20% or more from the average value of the displayed SpO 2 values within a predetermined determination period may be determined as an abnormal value and not used for calculation of the determination value.
  • the stability determination unit 43 performs approximation of the linear line using the least square method for each display SpO 2 value (for m points) within the determination target period, and determines the absolute value of the slope in the linear approximate line. It may be obtained as a value.
  • stability judging unit 43 similarly to the determination of the stability of the SpO 2 value according to the instantaneous SpO 2 value, calculated determination value, SpO 2 values when more than a predetermined threshold value is stable Can be judged. Note that the determination based on the display SpO 2 value may be performed using Equation 1 described in Patent Document 1 described above.
  • Stability judging unit 43 in the judgment of the stability of the SpO 2 value according to display SpO 2 values, determined the determination value, it is determined that the SpO 2 value when their value is less than the predetermined threshold value is stable Good. Further, the stability determination unit 43 may determine that the SpO 2 value is not stable when the abnormal value is included in a predetermined ratio or more within the determination target period. As the abnormal value, the average value of the display SpO 2 values within a predetermined period may be obtained as described above, and the average value may be a value deviated by about ⁇ 5 to 20% or more.
  • the stability decision unit 43, the signal component and the display SpO 2 values determined the stability of the SpO 2 values, when there is a high both stability, i.e. the signal components and the display SpO 2 value When both are evaluated and both satisfy the predetermined evaluation criteria, it is determined that the SpO 2 value is stable, and the display control unit 44 causes the display unit 6 to display the latest display SpO 2 value in a fixed manner. Specifically, it is represented by the flowchart shown in FIG. FIG. 3 is a flowchart showing stability determination. First, the measurement unit 2 performs measurement (S1).
  • the control unit 4 performs an analysis process on the biological information signal acquired by the measurement unit 2, and the light amount and pulse wave amplitude of each light that is a signal component received by the light receiving unit 22, the amplitude ratio of infrared light and red light. Then, the instantaneous SpO 2 value and the like are calculated (S2). Further, the display SpO 2 value is calculated based on the instantaneous SpO 2 value (S3), and the display SpO 2 value is displayed on the display unit 6 (S4).
  • the stability determination unit 43 determines at least one of the light amount and pulse wave amplitude of each light received by the light receiving unit 22 as a signal component, the amplitude ratio between infrared light and red light, and the instantaneous SpO 2 value.
  • SpO 2 value stability determination is performed based on the determination value DS 1 used. Specifically, first, stability judging unit 43 reads the data while going back the current value and the current in a predetermined period past from the storage unit 5, and calculates the determination value DS 1 based on them (S5) . The stability judging unit 43, the determination value DS 1 To assess whether a predetermined threshold TH 1 or less (S6).
  • the process returns to step S1 again. If the determination value DS 1 is less than or equal to the threshold value TH 1 , the stability determination unit 43 determines the determination value DS 2 using the display SpO 2 value. SpO 2 value stability determination based on Specifically, first, stability judging unit 43 reads the data while going back the current value and the current in a predetermined period past from the storage unit 5, to calculate a decision value DS 2 based on them (S7) . The stability judging unit 43, the determination value DS 2 To assess whether a predetermined threshold TH 2 below (S8).
  • step S1 If the determination value DS 2 is not the threshold TH 2 or less, process returns to step S1, if the determination value DS 2 the threshold TH 2 or less, on the display unit 6 is a display control unit 44, the latest display value i.e. currently displayed The SpO 2 value is fixed and displayed (S9). Note that after the fixed display, the measurement is not performed.
  • the pulse oximeter 100 includes a buzzer, a vibration device, an LED (Light Emitting Diode), or the like. When the pulse oximeter 100 is fixedly displayed, SpO 2 is transmitted to the operator by sound, vibration, or light. The fact that the value is stable is notified (S10).
  • stability judging unit 43 may be used at least one determination method of the determination method indicated above. Moreover, the stability determination part 43 may perform by using one determination value, and may perform determination using a some determination value. Furthermore, when using a plurality of determination values, the stability determination unit 43 may determine that the SpO 2 value is not stable unless all of the plurality of determination values used for the determination are equal to or less than the threshold. It is also possible to determine that the SpO 2 value is stable if the number or the determination value of a predetermined ratio is equal to or less than the threshold value.
  • the degree of the determination level may be changed stepwise. That is, it is preferable that the stability determination unit 43 can change the threshold stepwise. It should be noted that the stricter the determination level, the smaller the measurement value used for the determination, and the lower the determination level, the more the measurement value used for the determination.
  • the determination target period may be shortened as the determination level is stricter (the threshold value is small). Thereby, when the stability of the SpO 2 value is high, since the determination target period is short by setting the determination level to be strict, measurement can be performed in a short time.
  • the pulse oximeter 100 is attached to the subject's hand 300, and the operation unit 8 is operated to start measurement.
  • the operation unit 8 is operated to start measurement.
  • stability determination is performed and if it is determined that the SpO 2 value is stable, a stability determination mode in which the display is fixed, and continuous measurement is continued regardless of the value of the SpO 2 value. It is preferable that one of the measurement modes can be selected.
  • the measurement control unit 41 controls the light emitting unit 21, the light receiving unit 22, the I / V conversion unit 31, and the A / D conversion unit 32 to perform SpO 2. Measurement of biological information such as values is performed.
  • the measurement control unit 41 causes the light emitting unit 21 to emit light and causes the light receiving unit 22 to acquire a photoelectric conversion signal that is a biological information signal in synchronization with the light emission timing. Further, the photoelectric conversion signal acquired by the light receiving unit 22 is a current signal, is converted into a voltage signal by the I / V conversion unit 31, and is output to the A / D conversion unit 32 as a photoelectric pulse wave signal.
  • the measurement control unit 41 causes the A / D conversion unit 32 to convert the photoelectric pulse wave signal from analog to digital.
  • the analysis processing unit 42 performs a predetermined analysis based on the digital photoelectric pulse wave signal output from the A / D conversion unit 32, and the light amount and pulse wave amplitude of each light received by the light receiving unit 22 and infrared light. An amplitude ratio with red light, an instantaneous SpO 2 value, a display SpO 2 value, and the like are calculated.
  • the display control unit 44 causes the display unit 6 to display the display SpO 2 value calculated by the analysis processing unit 42.
  • the analysis processing unit 42 stores the calculated various parameters in the storage unit 5 together with the timing information.
  • the parameters stored in the storage unit 5 may be only those used for stability determination.
  • the stability determination unit 43 When the stability determination mode is selected by the operation unit 8, the stability determination unit 43 reads the parameters in the past measurement used for the stability determination from the storage unit 5, and stabilizes the SpO 2 value by the method described above. Judge the degree. Note that, as described above, in the case of having multi-level determination levels, the operator may select a desired determination level using the operation unit 8. Thereby, the stability determination part 43 performs the stability determination of a predetermined determination level within a predetermined determination target period.
  • the stability determination unit 43 may extend the determination target period and continue the determination. Specifically, for example, the stability determination unit 43 may change the determination level, and the determination level may be changed to a stricter determination level than the initially set determination level. That is, if it is not determined that the SpO 2 value is stable within the determination target period, it can be determined that the degree of instability of the SpO 2 value is high, and therefore the determination of the stability of the SpO 2 value is further continued. By making the conditions stricter, it is possible to realize a more reliable determination of the stability of the SpO 2 value.
  • the stability determination unit 43 determines that the SpO 2 value is stable, the stability determination unit 43 sends an instruction to that effect to the display control unit 44. Therefore, the display control unit 44 causes the display unit 6 to display the latest display SpO 2 value in a fixed manner.
  • the pulse oximeter 100 may be provided with a buzzer, a vibration device, an LED, or the like, and when fixedly displayed, the pulse oximeter 100 may be configured to notify the operator of the fixed display by sound, vibration, or light. . In this way, by notifying that the SpO 2 value has stabilized, the operator can know that the SpO 2 value has been stabilized and the fixed display has been made without looking at the display unit 6.
  • the measurement control unit 41 may stop the measurement. Moreover, the power supply part 7 should just stop a power supply automatically, if measurement for a fixed time is not made. As a result, the power source of the pulse oximeter 100 is automatically turned off after a fixed time has elapsed since the fixed display has been made, thus providing an energy saving effect.
  • the display control unit 44 displays the display SpO 2 value that is fixedly displayed when the display unit 6 is automatically turned off. The unit 6 may be controlled.
  • the operator can read the value when the SpO 2 value is stable without continuing to look at the display of the pulse oximeter. Moreover, since the reliability of the determination of the stability of the SpO 2 value is high, it can be said that the fixedly displayed value is a value in a state where the fluctuation of the SpO 2 value is small and is a correct measured value. Therefore, the pulse oximeter 100 according to the present embodiment allows the operator to correctly measure the SpO 2 value.
  • the determination of the stability of the SpO 2 value may be performed by another method other than the determination based on the display stability and the signal stability as described above.
  • the determination of the stability of the SpO 2 value may be performed only based on the signal stability.
  • the signal component is the value obtained by the measurement, since determining the stability of the SpO 2 values, reliable in stability judgment.
  • at least two values are included among the light amount and pulse wave amplitude of each light received by the light receiving unit 22, the amplitude ratio of infrared light and red light, the instantaneous SpO 2 value, the display SpO 2 value, and the like.
  • the SpO 2 value may be determined to be stable. More specifically, when evaluation is performed on at least two values of the signal component calculated by the analysis processing unit 42 without performing evaluation based on the display SpO 2 value, and all of these satisfy a predetermined evaluation criterion, The SpO 2 value may be determined to be stable. Further, signals calculated by the analysis processing unit 42, such as the light amount and pulse wave amplitude of each light received by the light receiving unit 22, the amplitude ratio of the infrared light and the red light, the instantaneous SpO 2 value, the display SpO 2 value, and the like. If only one value is evaluated among the components and this value satisfies a predetermined evaluation criterion, the SpO 2 value may be determined to be stable. This increases the degree of freedom in determining the stability of the SpO 2 value.
  • FIG. 4 is a flowchart showing an example of the operation of the pulse oximeter according to the embodiment.
  • the pulse oximeter 100 based on the stability and display SpO 2 value of the instantaneous SpO 2 value to determine the stability of the SpO 2 values.
  • the evaluation of the instantaneous SpO 2 value is performed based on the difference between the maximum value and the minimum value.
  • the measurement unit 2 performs measurement (S11).
  • the determination time T is measured by a timer function provided in the CPU. Therefore, the determination time T is set to 0 at the start of measurement, and measurement of the determination time is started.
  • the analysis processing unit 42 performs an analysis process on the biological information signal acquired by the measurement unit 2 and calculates an instantaneous SpO 2 value (S12).
  • the predetermined determination target period T 0 is compared with the determination time T (S13). If T is equal to or less than T 0 , that is, if the determination target period T 0 has not elapsed, the process returns to step S11 again.
  • the stability determination unit 43 reads the instantaneous SpO 2 value calculated in the determination target period T 0 and stored in the storage unit 5. An abnormal value is deleted from them (S14). Furthermore, the stability determination unit 43 calculates the difference between the maximum value and the minimum value in the instantaneous SpO 2 value from which the abnormal value is deleted (S15). Here, the difference between the maximum value and the minimum value is the determination value DS 1 at the instant SpO 2 value. Further, stability judging unit 43, a judgment value DS 2 of the display SpO 2 values within the determination target period T 0 is calculated by the above method (S16). The determination value DS 2 is, for example, like the instantaneous SpO 2 value may be a difference between the maximum value and the minimum value of the display SpO 2 values.
  • stability judging unit 43 the calculated determination value DS 1 To assess whether a predetermined threshold TH 1 or less (S17). If the determination value DS 1 is the threshold TH 1 or less, the stability determination unit 43 performs evaluation based on the determination value DS 2 using the display SpO 2 values. Specifically, stability judging unit 43, the determination value DS 2 To assess whether a predetermined threshold TH 2 or less (S18).
  • the display control unit 44 on the display unit 6 the latest display value ie is fixed displays the SpO 2 value currently displayed, comprising a pulse oximeter 100, a buzzer, vibration The operator notifies the operator that the SpO 2 value has been stabilized by sound, vibration, or light from the device or the LED (S19), and the process ends.
  • step S17 in a case and S18 determination value DS 1 is not the threshold TH 1 or less, if the determination value DS 2 is not the threshold TH 2 below, fixed display is not performed, the display control unit 44 The latest display SpO 2 value is updated and displayed on the display unit 6 (S20). Furthermore, the control unit 4 measures the time from the start of measurement using, for example, a timer function provided in the CPU, and determines whether or not a predetermined time has elapsed since the start of measurement (S21). The predetermined time may be about 30 seconds, for example. Further, the determination of the elapse of the predetermined time (step S21) may be omitted. In this case, if it is not determined to be stable, the determination target period is extended each time.
  • the measurement unit 2 returns to step S11 and continues measurement. If the predetermined time has not elapsed, the stability determination unit 43 extends the determination target period by ⁇ (S22), and the extended determination target period is applied in the next stability determination. Also, the determination condition is changed. Specifically, stability judging unit 43 changes the threshold value TH 1 and the threshold TH 2 values of the threshold TH 12 and the threshold value TH 22, respectively (S23). And it returns to step S11 again and repeats the above-mentioned operation.
  • the pulse oximeter according to the embodiment of the present invention, it is possible to determine whether or not the SpO 2 value is stable by a more reliable method.
  • the oxygen saturation measuring apparatus is an apparatus for measuring oxygen saturation in blood, which irradiates a living body with infrared light and red light and emits light that has passed through the living body.
  • a measurement unit that obtains a biological information signal by receiving light
  • an analysis processing unit that analyzes the biological information signal and calculates a signal component from the biological information signal, and the oxygen based on the calculated signal component
  • a stability determination unit that determines the stability of the saturation, and the stability determination unit evaluates the signal component, and the oxygen saturation is stabilized when the signal component satisfies a predetermined evaluation criterion. It is determined that
  • the stability of the oxygen saturation in the blood is determined based on the signal component that is the measured value, not the average value of the measured value, as in the displayed blood oxygen saturation. High reliability.
  • the signal component includes a light amount component of the received light, a pulse wave amplitude of the received light, and infrared light and red light of the received light. It is preferable to include at least one of the amplitude ratio and the instantaneous blood oxygen saturation.
  • the analysis processing unit calculates a plurality of signal components from the biological information signal, and the stability determination unit calculates at least two values of the plurality of signal components. It is preferable to evaluate each individually and determine that the oxygen saturation is stable when all of them satisfy a predetermined evaluation criterion.
  • the stability of the oxygen saturation level in the blood is determined based on at least two values of the plurality of signal components, the reliability in the stability determination is high.
  • the analysis processing unit further analyzes the biological information signal to calculate a displayed blood oxygen saturation
  • the stability determination unit includes at least one of the above-described stability determination units. It is preferable to individually evaluate the signal component and the displayed blood oxygen saturation, and determine that the oxygen saturation is stable when all of them satisfy a predetermined evaluation criterion.
  • the stability of the oxygen saturation level in the blood is determined based on both the signal component and the displayed blood oxygen saturation level, the reliability in the stability determination is high.
  • the oxygen saturation measurement apparatus further includes a display unit that displays the displayed blood oxygen saturation, and the display unit determines that the oxygen saturation is stable when the oxygen saturation is stable. Is determined, it is preferable not to update the display of the displayed blood oxygen saturation.
  • the display of the displayed blood oxygen saturation is not updated, so that the operator can display the displayed blood oxygen saturation fixedly. Therefore, it can be easily recognized that the oxygen saturation level in the blood is stable. Further, by reading the value, the display blood oxygen saturation with high reliability can be read.
  • the oxygen saturation measuring apparatus further includes a display unit that displays the displayed blood oxygen saturation, and the display unit is configured so that any one of the evaluated values is a predetermined evaluation criterion. If not, it is preferable to keep displaying the displayed blood oxygen saturation calculated by the analysis processing unit as needed.
  • the displayed blood oxygen saturation displayed on the display unit is updated as needed based on the value obtained by the measurement. Therefore, the operator can easily recognize that the oxygen saturation level in the blood is not stable by looking at the display unit.
  • the stability determination unit may evaluate each value of the amplitude ratio of the infrared light and the red light or the instantaneous blood oxygen saturation in the received light. The evaluation is preferably performed based on the difference between the maximum value and the minimum value of the respective values within the determination target period. In the evaluation of each value, the value obtained by the current measurement and the value obtained by the past measurement from the current time are used, and the period during which the value used for the evaluation is measured is referred to as a determination target period.
  • the maximum value and the minimum value are selected from among abnormal values deleted from the respective values within the determination target period.
  • the abnormal value is deleted from the value for evaluating each value, thereby realizing a more reliable determination of the stability of oxygen saturation in blood.
  • the abnormal value is determined based on an average value of the respective values within the determination target period.
  • the stability determination unit may include the pulse wave amplitude of the received light, the amplitude ratio of infrared light and red light of the received light, or the instantaneous In the evaluation of each value of blood oxygen saturation, it is preferable to perform the evaluation based on the standard deviation value of each value within the determination target period.
  • the stability determination unit determines the amplitude ratio of infrared light and red light or the instantaneous blood oxygen saturation value in the received light. It is preferable to determine that the oxygen saturation is not stable if the ratio of abnormal values is equal to or greater than a predetermined ratio among the values within the target period.
  • the stability determination unit may evaluate each value of the amplitude ratio of the infrared light and the red light or the instantaneous blood oxygen saturation in the received light. It is preferable that a primary approximate line is obtained from the respective values in the determination target period by a least square method and the evaluation is performed based on the absolute value of the slope of the primary approximate line.
  • the stability determination unit extends the determination target period when any of the plurality of signal components does not satisfy a predetermined evaluation criterion within the determination target period. In addition, it is preferable to change the evaluation criteria.
  • the evaluation standard can be changed and the evaluation target period can be extended to continue the evaluation. For example, if any of the plurality of signal components does not meet the predetermined evaluation criteria within the determination target period, it can be determined that the degree of instability of the oxygen saturation in the blood is high, and the evaluation is continued further.
  • the evaluation criteria should be made stricter. Thereby, a more reliable determination of the stability of the oxygen saturation in the blood is realized.
  • the evaluation criterion includes a plurality of evaluation criteria that are different in stages, and there are determination target periods corresponding to the respective stages of the evaluation criterion
  • the stability determination unit includes: Preferably, the evaluation is performed within the determination target period corresponding to the evaluation criterion by using any one of the evaluation criteria.
  • the level of reliability in determining the stability of the oxygen saturation can be maintained. For example, when the evaluation standard is strict, the determination target period may be shortened. Therefore, when the stability of oxygen saturation in the blood is high, the evaluation criteria are stricter, thereby shortening the determination target period, so that the measurement time can be shortened without lowering the reliability of stability determination.
  • the stability determination unit may determine the magnitude of each value in the evaluation of each value of the light amount component of the received light and the pulse wave amplitude of the received light. Accordingly, it is preferable to change the determination target period.
  • the determination target period may be shortened as each value increases.
  • the stability determination unit determines that the blood oxygen saturation is stable, it is preferable to notify that the oxygen saturation is stable. .

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Abstract

A device for measuring oxygen saturation degree for measuring the oxygen saturation degree in the blood which comprises: a measurement part in which a living body is irradiated with an infrared light and a red light and the light passing through the living body is received to thereby obtain data signals concerning the living body; an analysis and processing part in which the data signals concerning the living body are analyzed and processed to thereby compute signal components; and a stability determination part in which the stability of the oxygen saturation degree is determined based on the signal components thus computed; wherein, in the stability determination part, the signal components are evaluated so that the oxygen saturation degree is referred to as stable in the case where the signal components satisfy definite evaluation criteria.

Description

酸素飽和度測定装置Oxygen saturation measuring device
　本発明は、動脈血の酸素飽和度を測定する酸素飽和度測定装置に関するものである。 The present invention relates to an oxygen saturation measuring apparatus for measuring the oxygen saturation of arterial blood.
　パルスオキシメータ（酸素飽和度測定装置）は、患者の状態を知る上で、重要な測定装置である。具体的には、パルスオキシメータは、被験者の所定の生体部位に装着され、生体部位に向けて光を出力し、生体部位を透過又は反射した光の光量変化を信号として測定し、血中酸素飽和度（以下、ＳｐＯ２値）等を求める。例えば病院の外来の受付時等に、体温測定等と同様に、パルスオキシメータによるＳｐＯ２値の測定が行われることがある。また、特に循環器科の病棟では毎日の健康チェックとして、入院患者にパルスオキシメータを装着し、患者のＳｐＯ２値を測定している場合もある。 A pulse oximeter (oxygen saturation measuring device) is an important measuring device for knowing the patient's condition. Specifically, the pulse oximeter is attached to a predetermined living body part of a subject, outputs light toward the living body part, measures a change in the amount of light transmitted or reflected through the living body part as a signal, Saturation (hereinafter referred to as SpO 2 value) or the like is obtained. For example, when receiving an outpatient in a hospital, the SpO 2 value may be measured by a pulse oximeter in the same manner as body temperature measurement. In particular, in the cardiovascular ward, in-patients may be equipped with a pulse oximeter to measure the patient's SpO 2 value as a daily health check.
　例えば、呼吸不全の患者は、歩行するだけでも一時的にＳｐＯ２値が急激に低下する。このような状態でＳｐＯ２値を測定しても、ＳｐＯ２値が随時変化しており、正しい値を測定することはできない。そこで、患者にパルスオキシメータを装着後、ＳｐＯ２値が安定するまで、表示されているＳｐＯ２値を目視にて確認しておく必要がある。このようにして、ＳｐＯ２値が安定した状態で、読み取ったＳｐＯ２値が正しい値である。この作業は、通常、看護師等が行うが、目視にて確認しているため、この間は他の作業ができない。 For example, in a patient with respiratory failure, the SpO 2 value temporarily decreases abruptly just by walking. Be measured SpO 2 value in this state, SpO 2 value has changed from time to time, it is impossible to measure the correct value. Therefore, after mounting the pulse oximeter to the patient, until the SpO 2 value is stabilized, it is necessary to visually confirm the SpO 2 value displayed. In this way, the read SpO 2 value is the correct value while the SpO 2 value is stable. This operation is usually performed by a nurse or the like, but since it is confirmed visually, other operations cannot be performed during this period.
　例えば、特許文献１には、随時表示されるＳｐＯ２値から、ＳｐＯ２値の安定度を求め、ＳｐＯ２値が安定したと判定した場合には、それ以降の測定を行わず、そのときに表示されているＳｐＯ２値をそのまま固定表示するオキシメータが記載されている。ここで、このオキシメータの安定度の判定には、以下に示す式１を用いる。なお、式１において、ＤＳは判定値であり、Ｗ（Ｉ）は重み係数である。また、Ｓ（０）は現在表示されているＳｐＯ２値を表し、Ｓ（－１）は１つ前に表示されていたＳｐＯ２値を表し、Ｓ（－２）は２つ前に表示されていたＳｐＯ２値を表す。また、Ｗ（Ｉ）はＩによって決まる値である。
Figure JPOXMLDOC01-appb-I000001
For example, Patent Document 1, the SpO 2 value displayed at any time, determined the stability of the SpO 2 values, when the SpO 2 value is judged to be stable, without subsequent measurements, at that time An oximeter that displays the displayed SpO 2 value as it is is described. Here, Formula 1 shown below is used for the determination of the stability of the oximeter. In Equation 1, DS is a determination value, and W (I) is a weighting factor. S (0) represents the currently displayed SpO 2 value, S (-1) represents the previous SpO 2 value, and S (-2) displayed the previous two. It represents the SpO 2 value. W (I) is a value determined by I.
Figure JPOXMLDOC01-appb-I000001
　式１により求められた判定値ＤＳは、値が小さいほど表示ＳｐＯ２値の変動が少なく、安定度が高いことを示す。したがって、特許文献１に記載のオキシメータは、判定値ＤＳが所定の閾値以下であればＳｐＯ２値は安定していると判定し、そのとき表示しているＳｐＯ２値を固定表示とする。 The determination value DS obtained by Equation 1 indicates that the smaller the value, the less the change in the display SpO 2 value and the higher the stability. Therefore, oximeter described in Patent Document 1, the judgment value DS is equal to or smaller than the predetermined threshold value SpO 2 value is determined to be stable, and fixed displays the SpO 2 values displayed at that time.
　しかし、オキシメータにおいて表示される表示ＳｐＯ２値は、測定により得られた光信号から求めたＳｐＯ２値（瞬時ＳｐＯ２値）の連続した複数回分を平均する等して求めた値であり、１回の測定により得られた値とは異なる。そのため、表示ＳｐＯ２値があまり変化していないように見えるからといって、患者のＳｐＯ２値が実際に安定しているとは必ずしもいえないという問題があった。例えば、瞬時ＳｐＯ２値は不安定であっても、瞬時ＳｐＯ２値を平均化する等の演算処理を施して求められた表示ＳｐＯ２値は安定と判定される場合がある。このため、特許文献１に記載のオキシメータにおいては、実際にはＳｐＯ２値の安定度が低いにもかかわらず、安定していると判定し、ＳｐＯ２値を固定表示としてしまうという問題がある。 However, the display SpO 2 value displayed on the oximeter is a value obtained by, for example, averaging a plurality of consecutive SpO 2 values (instantaneous SpO 2 values) obtained from the optical signal obtained by measurement, It differs from the value obtained by one measurement. Therefore, just because the displayed SpO 2 value does not seem to change much, there is a problem that it cannot be said that the patient's SpO 2 value is actually stable. For example, even if the instantaneous SpO 2 value is unstable, the display SpO 2 value obtained by performing arithmetic processing such as averaging the instantaneous SpO 2 value may be determined to be stable. For this reason, the oximeter described in Patent Document 1 has a problem that although the stability of the SpO 2 value is actually low, it is determined that the SpO 2 value is stable and the SpO 2 value is fixedly displayed. .
特公平７－３２７６７号公報Japanese Patent Publication No. 7-32767
　本発明は、上述の事情に鑑みて為された発明であり、その目的は、ＳｐＯ２値が安定しているか否かの判定を、より信頼性の高い方法により行う酸素飽和度測定装置を提供することである。 The present invention has been made in view of the above circumstances, and an object thereof is to provide an oxygen saturation measuring device that performs a determination of whether or not the SpO 2 value is stable by a more reliable method. It is to be.
　本発明の酸素飽和度測定装置は、信号成分に基づいて、酸素飽和度の安定度を判定する安定度判定部を備え、安定度判定部は、信号成分を評価し、信号成分が所定の評価基準を満たす場合に、酸素飽和度が安定していると判定する。 The oxygen saturation measurement apparatus of the present invention includes a stability determination unit that determines the stability of oxygen saturation based on a signal component. The stability determination unit evaluates the signal component, and the signal component has a predetermined evaluation. When the standard is satisfied, it is determined that the oxygen saturation is stable.
　これにより、実際の測定により得られた信号成分に基づいて、酸素飽和度の安定度を判定するので、安定度判定における信頼性が高い酸素飽和度測定装置を提供できる。 Thereby, since the stability of the oxygen saturation is determined based on the signal component obtained by the actual measurement, it is possible to provide an oxygen saturation measuring device with high reliability in the stability determination.
実施の形態に係るパルスオキシメータの外観構成を示す図である。It is a figure which shows the external appearance structure of the pulse oximeter which concerns on embodiment. 実施の形態に係るパルスオキシメータの構成を示すブロック図である。It is a block diagram which shows the structure of the pulse oximeter which concerns on embodiment. 安定度判定を示すフローチャートである。It is a flowchart which shows stability determination. 実施の形態に係るパルスオキシメータの動作の一例を示すフローチャートである。It is a flowchart which shows an example of operation | movement of the pulse oximeter which concerns on embodiment.
　以下、本発明に係る実施の形態を図面に基づいて説明する。なお、各図において同一の符号を付した構成は、同一の構成であることを示し、その説明を省略する。 Hereinafter, embodiments of 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.
　本発明の実施の形態に係る酸素飽和度測定装置であるパルスオキシメータについて説明する。まず、実施の形態に係るパルスオキシメータの構成について説明する。図１は実施の形態に係るパルスオキシメータの外観構成を示す図である。図２は実施の形態に係るパルスオキシメータの構成を示すブロック図である。 A pulse oximeter that is an oxygen saturation measuring apparatus according to an embodiment of the present invention will be described. First, the configuration of the pulse oximeter according to the embodiment will be described. FIG. 1 is a diagram showing an external configuration of a pulse oximeter according to an embodiment. FIG. 2 is a block diagram showing the configuration of the pulse oximeter according to the embodiment.
　図１に示すように、パルスオキシメータ１００は、装置本体１と、ケーブル１６を介して装置本体１と電気的に接続された測定部２とを備えて構成されている。パルスオキシメータ１００は被験者（患者）の手３００に装着されて使用される。装置本体１は装着ベルト１７を有しており、例えば被験者の手首に装着ベルト１７が巻回されることで、装置本体１は被験者の手首に固定される。装置本体１はさらに表示部６および操作部８を有している。表示部６は測定結果すなわち血中酸素飽和度（ＳｐＯ２値）等の生体情報を表示するためのものである。また、操作部８は、例えば、スイッチ回路等であり測定結果の読み出し指示や測定開始または終了の指示を行うためのものである。なお、生体情報とは、パルスオキシメータが生体から得た電気信号を解析して得られる被験者のＳｐＯ２値や脈拍等の、生体の情報を表す指標となる情報である。 As shown in FIG. 1, the pulse oximeter 100 includes a device main body 1 and a measuring unit 2 electrically connected to the device main body 1 via a cable 16. The pulse oximeter 100 is used by being attached to a hand 300 of a subject (patient). The apparatus main body 1 has a mounting belt 17, and the apparatus main body 1 is fixed to the wrist of the subject by, for example, winding the mounting belt 17 around the wrist of the subject. The apparatus body 1 further includes a display unit 6 and an operation unit 8. The display unit 6 is for displaying biological information such as measurement results, that is, blood oxygen saturation (SpO 2 value). Further, the operation unit 8 is, for example, a switch circuit and the like, and is used for instructing reading of measurement results and instructions for starting or ending measurement. The biological information is information serving as an index representing biological information such as the SpO 2 value and pulse of the subject obtained by analyzing an electrical signal obtained from the living body by the pulse oximeter.
　測定部２は、例えば被験者の指先に装着される。具体的には、指サックのような形状を有しており、被験者の指先に嵌めることで装着される。図１には図示されていないが、測定部２の内側に設置された発光部２１および受光部２２により測定が行われる（図２参照）。 The measuring unit 2 is attached to the fingertip of the subject, for example. Specifically, it has a shape like a finger sack and is worn by being fitted to the fingertip of the subject. Although not shown in FIG. 1, measurement is performed by the light emitting unit 21 and the light receiving unit 22 installed inside the measuring unit 2 (see FIG. 2).
　さらに、特に図２を参照して、実施の形態に係るパルスオキシメータ１００の電気的な構成について説明する。パルスオキシメータ１００は、装置本体１および測定部２を備えて構成されている。測定部２は、発光部２１および受光部２２を備えていて、測定部位（例えば指先）が測定部２に嵌まり込んだ状態、すなわち測定状態において、発光部２１および受光部２２が間に指先を介して対向するような配置とされる。これにより、測定部位の透過光に基づいて、生体情報を測定することができる。なお、測定部位の反射光に基づいて、生体情報を測定することもでき、その場合は発光部２１と受光部２２とは隣接配置とされる。 Furthermore, with reference to FIG. 2 in particular, the electrical configuration of the pulse oximeter 100 according to the embodiment will be described. The pulse oximeter 100 includes an apparatus main body 1 and a measurement unit 2. The measuring unit 2 includes a light emitting unit 21 and a light receiving unit 22, and in a state where a measurement site (for example, a fingertip) is fitted in the measuring unit 2, that is, in a measurement state, the light emitting unit 21 and the light receiving unit 22 are interposed between the fingertips. It is arranged so as to face each other. Thereby, biological information can be measured based on the transmitted light of the measurement site. In addition, biological information can also be measured based on the reflected light of the measurement site, and in this case, the light emitting unit 21 and the light receiving unit 22 are arranged adjacent to each other.
　発光部２１は、例えば、赤色領域の波長を有する赤色光を発光する発光ダイオードと、赤外線領域の波長を有する赤外光を発光する発光ダイオードとを備えた光源である。なお、測定部位である指先の太さや受光部２２の受光感度が異なっていても、適正なレベルの出力が得られるようにするために、測定時において照射光量を一定の範囲内で調整可能とすることが好ましい。 The light emitting unit 21 is a light source including, for example, a light emitting diode that emits red light having a wavelength in the red region and a light emitting diode that emits infrared light having a wavelength in the infrared region. In order to obtain an appropriate level of output even if the thickness of the fingertip that is the measurement site or the light receiving sensitivity of the light receiving unit 22 is different, the amount of irradiation light can be adjusted within a certain range during measurement. It is preferable to do.
　受光部２２は、受光した光の強度に応じた大きさの電流を生成する、例えばシリコンフォトダイオード等の光電変換素子を備えて構成されている。受光部２２は、測定部位である被験者の指先を透過した発光部２１からの光を受光する。したがって、この光電変換素子は、発光部２１が発光する赤色光および赤外光に対して感度を有する。受光部２２では、具体的には、赤色光および赤外光の光信号を生体情報信号である電気信号へと変換して出力する。なお、生体情報信号とは、測定により得られた被験者の生体に依存する電気信号である。より具体的には、生体情報信号を解析等することで生体情報が得られる。 The light receiving unit 22 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. The light receiving unit 22 receives light from the light emitting unit 21 that has passed through the fingertip of the subject as the measurement site. Therefore, this photoelectric conversion element has sensitivity to red light and infrared light emitted from the light emitting unit 21. Specifically, the light receiving unit 22 converts optical signals of red light and infrared light into electrical signals that are biological information signals and outputs the electrical signals. The biological information signal is an electrical signal that depends on the living body of the subject obtained by measurement. More specifically, the biological information can be obtained by analyzing the biological information signal.
　装置本体１は、制御部４と、記憶部５と、表示部６と、電源部７と、操作部８と、Ｉ／Ｖ変換部３１と、Ａ／Ｄ変換部３２とを備えている。 The apparatus body 1 includes a control unit 4, a storage unit 5, a display unit 6, a power supply unit 7, an operation unit 8, an I / V conversion unit 31, and an A / D conversion unit 32.
　記憶部５は、パルスオキシメータ１００の制御プログラム等を記憶するＲＯＭ（Read　Only　Memory）や、演算処理や制御処理などのデータを一時的に格納するＥＥＰＲＯＭ（Electrically　Erasable　Programmable　ROM）やＲＡＭ（Random　Access　Memory）やフラッシュメモリ等の不揮発性メモリを備えている。記憶部５には、測定部２により得られた生体情報信号を解析処理部４２において解析処理して求めた、受光部２２において受光された各光の光量や脈波振幅、赤外光と赤色光との振幅比率、瞬時ＳｐＯ２値（瞬時血中酸素飽和度）および表示ＳｐＯ２値（表示血中酸素飽和度）等が、計時情報に関連付けられて格納されている。ここで、瞬時ＳｐＯ２値とは、１回の測定動作により得られた生体情報信号から算出されたＳｐＯ２値である。また、表示ＳｐＯ２値とは、所定期間において算出された複数の瞬時ＳｐＯ２値の平均値あるいは移動平均値であって、表示部６に表示するための値である。瞬時ＳｐＯ２値は、１回の測定により得られたそのままの値なので、瞬時ＳｐＯ２値を測定毎に表示部６に表示すると、瞬時ＳｐＯ２値が微妙に変化している場合には表示がちらつく。そのため、表示された値を読み取ることは、操作者にとって困難である。そこで、一定期間において測定された瞬時ＳｐＯ２値の平均値あるいは移動平均値が、表示ＳｐＯ２値として表示部６に表示される。なお、ＳｐＯ２値の安定度の判定には、現在から一定期間過去にさかのぼったデータを用いるが、格納されるデータは、このように計時情報に関連付けて格納されることで、過去データの読み出しを容易に行うことができる。なお、計時情報としては、測定開始からの時間としてもよいし、時刻としてもよい。 The storage unit 5 includes a ROM (Read Only Memory) that stores a control program of the pulse oximeter 100, an EEPROM (Electrically Erasable Programmable ROM) that temporarily stores data such as arithmetic processing and control processing, and a RAM (Random Access). Memory) and flash memory. In the storage unit 5, the biological information signal obtained by the measurement unit 2 is analyzed by the analysis processing unit 42, and the light amount and pulse wave amplitude of each light received by the light receiving unit 22, infrared light and red color are obtained. The amplitude ratio with light, the instantaneous SpO 2 value (instantaneous blood oxygen saturation), the display SpO 2 value (displayed blood oxygen saturation), and the like are stored in association with the timing information. Here, the instantaneous SpO 2 value is an SpO 2 value calculated from a biological information signal obtained by one measurement operation. The display SpO 2 value is an average value or a moving average value of a plurality of instantaneous SpO 2 values calculated in a predetermined period, and is a value to be displayed on the display unit 6. Since the instantaneous SpO 2 value is the same value obtained by one measurement, when the instantaneous SpO 2 value is displayed on the display unit 6 for each measurement, the display is displayed when the instantaneous SpO 2 value slightly changes. Flicker. Therefore, it is difficult for the operator to read the displayed value. Therefore, the average value or the moving average value of the instantaneous SpO 2 values measured in a certain period is displayed on the display unit 6 as the display SpO 2 value. The determination of the stability of the SpO binary value uses data going back for a certain period from the present, but the stored data is stored in association with the timing information in this way, so that past data can be read out. Can be easily performed. Note that the time measurement information may be time from the start of measurement or time.
　表示部６は、例えばＬＣＤ（Liquid　Crystal　Display）、７セグメントＬＥＤ（Light　Emitting　Diode）や有機エレクトロルミネッセンス表示装置やＣＲＴ(Cathode　Ray　Tube)表示装置等の表示装置からなる。表示部６は、例えば測定された生体情報であるＳｐＯ２値等および測定中あるいは固定表示であることを示す情報等を表示する。例えば、表示部６は、点灯、点滅、文字、数字、記号、絵記号およびキャラクタ等の表示を行えばよい。 The display unit 6 includes a display device such as an LCD (Liquid Crystal Display), a 7-segment LED (Light Emitting Diode), an organic electroluminescence display device, or a CRT (Cathode Ray Tube) display device. The display unit 6 displays, for example, SpO 2 value, which is measured biological information, and information indicating that the measurement is being performed or a fixed display. For example, the display unit 6 may display lighting, blinking, characters, numbers, symbols, pictorial symbols, characters, and the like.
　電源部７は、パルスオキシメータ１００、すなわち測定部２および装置本体１に電力を供給する。パルスオキシメータ１００装着時の煩わしさを考慮すると、電源供給用のケーブルを不要とすることが望ましい。したがって、電源部７はボタン電池や２次電池等を備えることとすればよい。なお、電源部７は、一定時間測定がなされないと、自動的に電源供給を停止する、パワーオフ機能を有する電源回路を備えることが好ましい。 The power supply unit 7 supplies power to the pulse oximeter 100, that is, the measurement unit 2 and the apparatus main body 1. Considering the troublesomeness when the pulse oximeter 100 is mounted, it is desirable to eliminate the need for a power supply cable. Therefore, the power supply unit 7 may include a button battery, a secondary battery, and the like. In addition, it is preferable that the power supply part 7 is provided with the power supply circuit which has a power-off function which stops a power supply automatically, if a measurement is not made for a fixed time.
　操作部８は、パルスオキシメータ１００を操作するためのスイッチやボタンが設置されて構成されている。具体的には、電源をＯＮ／ＯＦＦするためのスイッチや、測定開始、測定延長およびそれら以外の各種操作を指示するスイッチ等を備える。また、安定度判定条件のレベルを変化させるよう指示できるボタンや、安定度判定を行い、ＳｐＯ２値が安定と判定された場合は固定表示とする安定度判定モードおよび連続して測定を続ける連続測定モードの切り替えを行うスイッチ等を備える。 The operation unit 8 is configured with switches and buttons for operating the pulse oximeter 100. Specifically, a switch for turning on / off the power, a switch for instructing measurement start, measurement extension, and various other operations are provided. In addition, a button that can instruct to change the level of the stability determination condition, a stability determination mode in which stability determination is performed and the SpO 2 value is determined to be stable, and continuous measurement that continues measurement A switch or the like for switching the measurement mode is provided.
　Ｉ／Ｖ変換部３１は、所定の周期で受光部２２から出力される電流信号を電圧信号に変換し、この電圧信号を光電脈波信号としてＡ／Ｄ変換部３２に出力するものである。 The I / V conversion unit 31 converts a current signal output from the light receiving unit 22 into a voltage signal at a predetermined cycle, and outputs the voltage signal to the A / D conversion unit 32 as a photoelectric pulse wave signal.
　Ａ／Ｄ変換部３２ は、Ｉ／Ｖ変換部３１から出力されたアナログの生体情報信号である光電脈波信号をデジタルの光電脈波信号に変換し、制御部４に出力するものである。 The A / D conversion unit 32 変 換 converts the photoelectric pulse wave signal, which is an analog biological information signal output from the I / V conversion unit 31, into a digital photoelectric pulse wave signal and outputs it to the control unit 4.
　制御部４は、各種電子部品や集積回路部品、ＣＰＵ（Central　Processing　Unit）等からなり、パルスオキシメータ１００の各部の動作制御を行うもので、機能的に測定制御部４１、解析処理部４２、安定度判定部４３および表示制御部４４を備えて構成されている。 The control unit 4 includes various electronic components, integrated circuit components, a CPU (Central Processing Unit), and the like, and controls the operation of each unit of the pulse oximeter 100. Functionally, the measurement control unit 41, the analysis processing unit 42, A stability determination unit 43 and a display control unit 44 are provided.
　測定制御部４１は、所定の測定プログラムにより測定部２による生体情報の測定動作を制御する。具体的には、サンプリング周期毎に発光部２１から、赤色光と赤外光とを交互に射出させると共に、その発光タイミングに同期させて受光部２２から光電変換信号を取得する。 The measurement control unit 41 controls the measurement operation of biological information by the measurement unit 2 according to a predetermined measurement program. Specifically, red light and infrared light are alternately emitted from the light emitting unit 21 at each sampling period, and a photoelectric conversion signal is acquired from the light receiving unit 22 in synchronization with the light emission timing.
　表示制御部４４は、測定中の状態を表す表示または測定により得られた生体情報信号を解析処理部４２にて解析されて算出された表示ＳｐＯ２値等を、所定の表示形態で表示部６へ表示させる表示動作等を制御する。また、安定度判定部４３においてＳｐＯ２値が安定したと判定された場合は、表示制御部４４はＳｐＯ２値を表示部６に固定表示とさせる。なお、固定表示とは、現在表示されている値をそのまま表示し続ける（表示を更新しない）こと、すなわち、表示血中酸素飽和度の表示を更新しないことをいう。したがって、固定表示された後には、実際の測定動作が行われ、それにより表示された値とは異なるＳｐＯ２値が算出されていたとしても、表示部６に表示されるＳｐＯ２値は変化しない。ここで、固定表示されている値は、ＳｐＯ２値が安定したときの値であるから、被験者のＳｐＯ２値としては、この固定表示されている値がばらつきのない正しい値である。なお、固定表示されるＳｐＯ２値としては、ＳｐＯ２値が安定であると判定された期間における任意のタイミングの表示ＳｐＯ２値を用いてもよく、また、ＳｐＯ２値が安定であると判定された期間において表示されたすべての表示ＳｐＯ２値の平均値を用いてもよい。 The display control unit 44 displays the display SpO 2 value and the like calculated by analyzing the biological information signal obtained by the display representing the state under measurement or the measurement by the analysis processing unit 42 in a predetermined display form. Controls the display operation to be displayed. When the stability determination unit 43 determines that the SpO 2 value is stable, the display control unit 44 causes the display unit 6 to display the SpO 2 value fixedly. The fixed display means that the currently displayed value is continuously displayed (the display is not updated), that is, the display of the displayed blood oxygen saturation is not updated. Accordingly, after being fixed display is performed actual measurement operation, even as different SpO 2 value has been calculated and thereby the displayed value, the SpO 2 value displayed on the display unit 6 does not change . Here, since the fixedly displayed value is a value when the SpO 2 value is stabilized, the fixedly displayed value is a correct value without variation as the SpO 2 value of the subject. As the SpO 2 value is fixed display may be used a display SpO 2 values of arbitrary timing in the period of SpO 2 value is determined to be stable, also, SpO 2 value to be stable determination it may be using the average value of all the listed display SpO 2 values in period.
　解析処理部４２は、測定部２にて得られた生体情報信号に基づき所定のデータ解析を行い、受光部２２において受光された各光の光量や脈波振幅、赤外光と赤色光との振幅比率、および瞬時ＳｐＯ２値等を求める。また、所定期間における瞬時ＳｐＯ２値の平均値あるいは移動平均値を算出し、表示部６に表示するための値である表示ＳｐＯ２値を求める。 The analysis processing unit 42 performs predetermined data analysis based on the biological information signal obtained by the measurement unit 2, and the light amount and pulse wave amplitude of each light received by the light receiving unit 22, the infrared light and the red light. An amplitude ratio, an instantaneous SpO 2 value, and the like are obtained. Further, an average value or moving average value of instantaneous SpO 2 values in a predetermined period is calculated, and a display SpO 2 value that is a value to be displayed on the display unit 6 is obtained.
　酸素は、血液により運搬されることで生体内の各部に供給される。より具体的には、酸素は、血液中のヘモグロビンの酸化、還元によって運搬されている。このヘモグロビンは、酸化されると赤色光の吸収が減少して赤外光の吸収が増加し、逆に還元されると赤色光の吸収が増加して赤外光の吸収が減少するという光学的特性を有している。解析処理部４２は、この特性を利用してＳｐＯ２値を算出する。具体的には、まず、受光部２２で受光された赤色光および赤外光の透過光量の変動を計測し、さらに赤色光および赤外光の振幅比率によりサンプリング周期ごとにおける瞬時ＳｐＯ２値を算出する。また、算出した瞬時ＳｐＯ２値の、例えば所定範囲における平均値あるいは移動平均値を求め、これを表示ＳｐＯ２値とする。表示ＳｐＯ２値は、表示制御部４４により表示部６に表示される。なお、表示ＳｐＯ２値は、サンプリング周期ごとに算出されることとしてもよいし、例えば１秒ごと等、所定の期間ごとに算出されることとしてもよい。 Oxygen is supplied to each part in the living body by being transported by blood. More specifically, oxygen is transported by oxidation and reduction of hemoglobin in 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 analysis processing unit 42 calculates the SpO 2 value using this characteristic. Specifically, first, the variation in the amount of transmitted light of red light and infrared light received by the light receiving unit 22 is measured, and the instantaneous SpO 2 value for each sampling period is calculated based on the amplitude ratio of the red light and infrared light. To do. Further, for example, an average value or a moving average value in a predetermined range of the calculated instantaneous SpO 2 value is obtained, and this is set as a display SpO 2 value. The display SpO 2 value is displayed on the display unit 6 by the display control unit 44. Note that the display SpO 2 value may be calculated every sampling cycle, or may be calculated every predetermined period, for example, every second.
　安定度判定部４３は、受光部２２において受光された各光の光量や脈波振幅、赤外光と赤色光との振幅比率および瞬時ＳｐＯ２値等の少なくともいずれか、および表示ＳｐＯ２値に基づいて、ＳｐＯ２値が安定しているか否かを判定する。具体的には、安定度判定部４３は、現在の値および現在から一定期間過去にさかのぼった間の測定により得られたデータを記憶部５から読み出し、評価する。具体的には、記憶部５から読み出したデータを所定の計算式に代入することで判定値を求める。なお、ＳｐＯ２値の安定度が高いほど判定値は小さくなるように前記計算式は設定される。それにより、この判定値が所定の閾値以下である場合、すなわち所定の評価基準を満たす場合は、ＳｐＯ２値は安定していると判定される。 The stability determination unit 43 sets at least one of the light amount and pulse wave amplitude of each light received by the light receiving unit 22, the amplitude ratio between infrared light and red light, the instantaneous SpO 2 value, and the display SpO 2 value. Based on this, it is determined whether the SpO 2 value is stable. Specifically, the stability determination unit 43 reads from the storage unit 5 and evaluates the current value and the data obtained by the measurement from the present to the past for a certain period of time. Specifically, the determination value is obtained by substituting the data read from the storage unit 5 into a predetermined calculation formula. The calculation formula is set so that the determination value decreases as the stability of the SpO 2 value increases. Thereby, when this determination value is below a predetermined threshold value, that is, when a predetermined evaluation criterion is satisfied, it is determined that the SpO 2 value is stable.
　安定度判定部４３では、具体的には、信号成分である受光部２２において受光された各光の光量や脈波振幅、赤外光と赤色光との振幅比率および瞬時ＳｐＯ２値等の少なくともいずれかに基づいて判定されるＳｐＯ２値の安定度である信号安定度と、瞬時ＳｐＯ２値より算出した表示部６に表示される表示ＳｐＯ２値に基づいて判定されるＳｐＯ２値の安定度である表示安定度との両方を用いてＳｐＯ２値の安定度を判定する。このように、実施の形態に係るパルスオキシメータ１００は、表示安定度だけでなく、信号安定度も用いてＳｐＯ２値の安定度を判定することから、より信頼性の高いＳｐＯ２値の安定度判定を行うことができる。なお、信号安定度を求めるための信号成分には、複数のパラメータがある。そこで、安定度判定部４３は、これらすべてのパラメータを評価して、ＳｐＯ２値の安定度を判定してもよいし、少なくともいずれか一つのパラメータを評価して、ＳｐＯ２値の安定度を判定してもよい。各パラメータの評価方法について、以下に説明する。具体的には、評価対象である各値のそれぞれを個別に評価し、各値が所定の評価基準を満たす場合は、ＳｐＯ２値は安定であると判定される。より、具体的には、判定値が求められ、その値が所定の閾値以下の場合にはＳｐＯ２値は安定であると判定される。 Specifically, the stability determination unit 43 includes at least the light amount and pulse wave amplitude of each light received by the light receiving unit 22 that is a signal component, the amplitude ratio between infrared light and red light, and the instantaneous SpO 2 value. and signal stability is stability of the SpO 2 value is determined on the basis of either stable SpO 2 value is determined based on the display SpO 2 value displayed on the display section 6 that is calculated from the instantaneous SpO 2 value The stability of the SpO 2 value is determined using both the display stability, which is a degree. Thus, the pulse oximeter 100 according to the embodiment, the display not only stability, since determining the stability of the signal stability be used SpO 2 value, stability of more reliable SpO 2 value Degree determination can be performed. The signal component for obtaining the signal stability has a plurality of parameters. Therefore, the stability determination unit 43 may evaluate all these parameters to determine the stability of the SpO 2 value, or may evaluate at least one of the parameters to determine the stability of the SpO 2 value. You may judge. A method for evaluating each parameter will be described below. Specifically, each value to be evaluated is individually evaluated, and if each value satisfies a predetermined evaluation criterion, it is determined that the SpO 2 value is stable. More specifically, a determination value is obtained, and when the value is equal to or smaller than a predetermined threshold, it is determined that the SpO 2 value is stable.
　まず、透過光量を評価して、ＳｐＯ２値の安定度を判定する場合について説明する。透過光量の光量の大きさが十分ではない場合はＳＮ比（Signal　to　Noise　Ratio：信号対雑音比）が悪くなることから、現在および現在から過去数点における透過光量の平均値から、安定度合いを知ることができる。例えば、現在の測定による値を含むｍ点間（ｍは１以上の整数）の透過光量の平均値の逆数を判定値とすればよい。なお、ｍは１０程度とすればよい。具体的には、判定値ＤＳ１１は以下で示す式２で表される。
Figure JPOXMLDOC01-appb-I000002
First, a case where the amount of transmitted light is evaluated to determine the stability of the SpO 2 value will be described. If the amount of transmitted light is not sufficient, the signal-to-noise ratio (SNR) will deteriorate, so the degree of stability can be determined from the average value of the transmitted light at the current and present several points. I can know. For example, the determination value may be the reciprocal of the average value of the amount of transmitted light between m points (m is an integer of 1 or more) including the value measured at present. Note that m may be about 10. Specifically, the determination value DS 11 is expressed by Equation 2 shown below.
Figure JPOXMLDOC01-appb-I000002
　式２において、ｎ（ｎは１以上の整数）は測定開始から現在までの測定値の個数である。すなわち、測定開始から、解析処理部４２では現在までｎ回、生体情報信号を受信し、解析処理を行っている。また、Ｌ（ｋ）は、測定開始からｋ（ｍは１以上の整数）回目の測定による、透過光量を表す。なお、判定値ＤＳ１１を平均値の逆数としているのは、判定値ＤＳ１１が小さい場合をＳｐＯ２値の安定度が高いこととするためである。そして、所定の閾値を決めておき、判定値ＤＳ１１がその閾値以下の場合にはＳｐＯ２値の安定度が高いと判定される。ここで、ＳｐＯ２値の安定度の判定においては、現時点の測定により得られた値と、現時点より過去の測定により得られた値を用いる。具体的には、現時点と、現時点から過去にさかのぼった間の値とをｍ個用いて判定値ＤＳ１１を求める。なお、これら判定に用いる値が測定された期間を判定対象期間という。すなわち、判定対象期間内において、測定部２はｍ回測定を行い、解析処理部４２はｍ個の生体信号情報を受光部２２から受信している。式２により、安定度判定部４３は、判定値ＤＳ１１を求め、これらが所定の閾値以下の場合にＳｐＯ２値の安定度が高いと判定すればよい。 In Equation 2, n (n is an integer of 1 or more) is the number of measurement values from the start of measurement to the present. That is, from the start of measurement, the analysis processing unit 42 has received the biological information signal n times to the present and performs analysis processing. L (k) represents the amount of transmitted light in the kth measurement (m is an integer of 1 or more) from the start of measurement. It is noted that the reason why the determination value DS 11 is the reciprocal of the mean value, the case where the determination value DS 11 is small in order to the high stability of the SpO 2 values. The previously determined a predetermined threshold value, determination value DS 11 is in the following cases the threshold is determined to be high stability of SpO 2 values. Here, in determining the stability of the SpO 2 value, a value obtained by the current measurement and a value obtained by the past measurement from the current time are used. Specifically, obtaining a present time, the determination value DS 11 and the value with the m while going back from the current time in the past. The period during which the values used for these determinations are measured is referred to as a determination target period. That is, the measurement unit 2 performs m measurements within the determination target period, and the analysis processing unit 42 receives m pieces of biological signal information from the light receiving unit 22. By Equation 2, stability judging unit 43 obtains the determination value DS 11, may determine these the higher stability of the SpO 2 values when more than a predetermined threshold value.
　なお、透過光量が大きいほど、ＳＮ比が良くなりＳｐＯ２値の安定度が高くなることから、透過光量が大きい場合は判定対象期間を短くしても、信頼度の高い判定を行うことができる。したがって、透過光量が小さいほど、判定対象期間を長くすることが好ましい。そこで、安定度判定部４３は、透過光量の大きさに応じて判定対象期間を変更できることが好ましい。そして、安定度判定部４３は、具体的には、透過光量が大きいほど、判定対象期間を短くすることとすればよい。なお、反射光を受光部２２で受光するタイプのパルスオキシメータであれば、前記透過光量の代わりに反射光量を用いればよい。 Note that the greater the amount of transmitted light, the better the SN ratio and the higher the stability of the SpO 2 value. Therefore, when the amount of transmitted light is large, a highly reliable determination can be made even if the determination target period is shortened. . Therefore, it is preferable to lengthen the determination target period as the transmitted light amount is smaller. Therefore, it is preferable that the stability determination unit 43 can change the determination target period in accordance with the amount of transmitted light. And the stability determination part 43 should just make the determination object period short, specifically, so that the transmitted light amount is large. In the case of a pulse oximeter that receives reflected light by the light receiving unit 22, the reflected light amount may be used instead of the transmitted light amount.
　次に脈波振幅を評価して、ＳｐＯ２値の安定度を判定する場合について説明する。脈波振幅も、透過光量と同様に振幅レベルが十分ではない場合はＳＮ比（Signal　to　Noise　Ratio：信号対雑音比）が悪くなる。したがって、透過光量と同様に、脈波振幅についても平均値を用いてＳｐＯ２値の安定度を判定することができる。また、脈波振幅を評価して、ＳｐＯ２値の安定度を判定する場合には、標準偏差を用いてもよい。具体的には、脈波振幅の大きさのバラツキを判定値としてもよい。これにより、脈波が大きく乱れていてＳｐＯ２値が安定でない場合には、判定値が比較的大きくなる。具体的には、脈波振幅の平均値を用いる場合の判定値ＤＳ１２は、以下に示す式３で表され、脈波振幅の標準偏差を用いる場合の判定値ＤＳ１３は、以下に示す式４で表される。
Figure JPOXMLDOC01-appb-I000003
Figure JPOXMLDOC01-appb-I000004
Next, the case where the pulse wave amplitude is evaluated to determine the stability of the SpO 2 value will be described. Similarly to the transmitted light amount, the pulse wave amplitude also has a poor SN ratio (Signal to Noise Ratio) when the amplitude level is not sufficient. Therefore, the stability of the SpO 2 value can be determined using the average value of the pulse wave amplitude as well as the transmitted light amount. Further, when evaluating the pulse wave amplitude and determining the stability of the SpO 2 value, a standard deviation may be used. Specifically, variation in the magnitude of the pulse wave amplitude may be used as the determination value. Thereby, when the pulse wave is greatly disturbed and the SpO 2 value is not stable, the determination value becomes relatively large. Specifically, the determination value DS 12 when the average value of the pulse wave amplitude is used is expressed by the following Expression 3, and the determination value DS 13 when the standard deviation of the pulse wave amplitude is used is the following expression: It is represented by 4.
Figure JPOXMLDOC01-appb-I000003
Figure JPOXMLDOC01-appb-I000004
　なお、式４において、ｌはｋと同じ値である。Ａ（ｋ）およびＡ（ｌ）は測定開始からｋ回目およびｌ回目の測定による脈波振幅を表す。これらの式により、安定度判定部４３は、判定値ＤＳ１２、ＤＳ１３を求め、これらが所定の閾値以下の場合にＳｐＯ２値の安定度が高いと判定すればよい。 In Equation 4, l is the same value as k. A (k) and A (l) represent pulse wave amplitudes from the k-th and l-th measurements from the start of measurement. From these equations, the stability determination unit 43 may determine the determination values DS 12 and DS 13 and determine that the stability of the SpO 2 value is high when they are equal to or less than a predetermined threshold.
　また、透過光量と同様に脈波振幅が大きいほど、ＳＮ比が良くなりＳｐＯ２値の安定度が高くなることから、脈波振幅が大きい場合には判定対象期間を短くしても、信頼度の高い判定を行うことができる。そこで、安定度判定部４３は、脈波振幅の大きさに応じて判定対象期間を変更できることが好ましい。そして、安定度判定部４３は、具体的には、脈波振幅が大きいほど、判定対象期間を短くすることとすればよい。 Further, as the pulse wave amplitude is larger as in the transmitted light amount, the SN ratio is improved and the stability of the SpO 2 value is increased. Therefore, if the pulse wave amplitude is large, the reliability can be reduced even if the determination target period is shortened. A high determination can be made. Therefore, it is preferable that the stability determination unit 43 can change the determination target period according to the magnitude of the pulse wave amplitude. And specifically, the stability determination part 43 should just shorten a determination object period, so that a pulse wave amplitude is large.
　また、瞬時ＳｐＯ２値を評価して、ＳｐＯ２値の安定度を判定する場合について説明する。瞬時ＳｐＯ２値により判定する場合は、脈波振幅の場合と同様に、標準偏差を用いて判定すればよい。具体的には、この場合の判定値ＤＳ１４は、以下に示す式５により表される。
Figure JPOXMLDOC01-appb-I000005
A case will be described in which the instantaneous SpO 2 value is evaluated to determine the stability of the SpO 2 value. When the determination is made based on the instantaneous SpO 2 value, the determination may be made using the standard deviation as in the case of the pulse wave amplitude. Specifically, the determination value DS 14 in this case is represented by Equation 5 shown below.
Figure JPOXMLDOC01-appb-I000005
　なお、式５において、ｓ（ｋ）およびｓ（ｌ）は測定開始からｋ回目およびｌ回目の測定による瞬時ＳｐＯ２値を表す。式５により、安定度判定部４３は判定値ＤＳ１４を求め、その値が所定の閾値以下の場合にＳｐＯ２値の安定度が高いと判定すればよい。 In Equation 5, s (k) and s (l) represent instantaneous SpO 2 values obtained by the k-th and l-th measurements from the start of measurement. According to Equation 5, the stability determination unit 43 may determine the determination value DS 14 and determine that the stability of the SpO 2 value is high when the value is equal to or less than a predetermined threshold.
　また、瞬時ＳｐＯ２値の判定対象期間内における値のうち最大値と最小値との差を判定値としてもよい。この場合も、安定度判定部４３は判定値が所定の閾値以下の場合にＳｐＯ２値の安定度が高いと判定すればよい。この判定値においては、例えば、閾値は瞬時ＳｐＯ２値の０．５％程度とすればよい。なお、この判定値を算出する場合は、最大値および最小値のうちから、異常値は削除しておくことが好ましい。安定度判定部４３は、例えば、所定の期間内における瞬時ＳｐＯ２値の平均値を求め、平均値より±５～２０％程度以上外れた値であれば異常値と判断し、判定値の算出には用いないこととすればよい。 Further, the difference between the maximum value and the minimum value among the values within the determination target period of the instantaneous SpO 2 value may be used as the determination value. Also in this case, the stability determination unit 43 may determine that the stability of the SpO 2 value is high when the determination value is equal to or less than a predetermined threshold. In this determination value, for example, the threshold value may be about 0.5% of the instantaneous SpO 2 value. When calculating the determination value, it is preferable to delete the abnormal value from the maximum value and the minimum value. For example, the stability determination unit 43 obtains an average value of instantaneous SpO 2 values within a predetermined period, and determines an abnormal value if the value deviates by about ± 5 to 20% or more from the average value, and calculates a determination value. Should not be used.
　また、安定度判定部４３は、判定対象期間内における各瞬時ＳｐＯ２値（ｍ点分）について、最小二乗法を用いて一次直線の近似を行い、その一次近似直線における傾きの絶対値を判定値として求めてもよい。このようにして算出された判定値は、瞬時ＳｐＯ２値の連続的な変化を示すものである。つまり、連続的に瞬時ＳｐＯ２値が降下または上昇している場合は、この判定値は比較的大きくなる。そして、このような場合は、ＳｐＯ２値は安定ではなく、前記近似直線の傾きが小さいほどＳｐＯ２値の安定度が高い。したがって、安定度判定部４３は、算出された判定値が、所定の閾値以下の場合にＳｐＯ２値が安定であると判定すればよい。なお、瞬時ＳｐＯ２値による判定においては、安定度判定部４３は、上述の特許文献１に記載の式１を用いて行ってもよい。 In addition, the stability determination unit 43 performs approximation of the linear line using the least square method for each instantaneous SpO 2 value (for m points) within the determination target period, and determines the absolute value of the slope in the linear approximate line. It may be obtained as a value. The determination value calculated in this way indicates a continuous change in the instantaneous SpO 2 value. That is, when the instantaneous SpO 2 value continuously decreases or increases, this determination value becomes relatively large. In such a case, the SpO 2 value is not stable, and the smaller the slope of the approximate line, the higher the stability of the SpO 2 value. Therefore, the stability determination unit 43 may determine that the SpO 2 value is stable when the calculated determination value is equal to or less than a predetermined threshold value. Note that, in the determination based on the instantaneous SpO 2 value, the stability determination unit 43 may use the equation 1 described in Patent Document 1 described above.
　安定度判定部４３は、瞬時ＳｐＯ２値によるＳｐＯ２値の安定度の判定において、上記判定値を求め、それらの値が所定の閾値以下の場合にＳｐＯ２値が安定であると判定すればよい。また、安定度判定部４３は、判定対象期間内において、異常値が所定の割合以上含まれる場合は、ＳｐＯ２値が安定していないと判定してもよい。なお、異常値は、上述と同様に、所定の期間内における瞬時ＳｐＯ２値の平均値より±５～２０％程度以上外れた値とすればよい。 Stability judging unit 43, in the judgment of the stability of the SpO 2 value according to the instantaneous SpO 2 values, determined the determination value, it is determined that the SpO 2 value when their value is less than the predetermined threshold value is stable Good. In addition, the stability determination unit 43 may determine that the SpO 2 value is not stable when the abnormal value is included in a predetermined ratio or more within the determination target period. Note that the abnormal value may be a value that deviates by about ± 5 to 20% or more from the average value of the instantaneous SpO 2 values within a predetermined period, as described above.
　なお、瞬時ＳｐＯ２値は、赤外光および赤色光の振幅比率により求めるものであることから、上記瞬時ＳｐＯ２値を用いた各判定値の算出において、瞬時ＳｐＯ２値の代わりに赤外光および赤色光の振幅比率を用いてもよく、同様の判定値を得ることができる。したがって、上記説明した、瞬時ＳｐＯ２値を用いた判定においては、瞬時ＳｐＯ２値の代わりに赤外光および赤色光の振幅比率を用いてもよい。具体的には、安定度判定部４３は、赤外光および赤色光の振幅比率の標準偏差が所定の閾値以下の場合にＳｐＯ２値が安定であると判定すればよい。また、赤外光および赤色光の振幅比率の最大値と最小値との差を判定値とし、安定度判定部４３はこの判定値が所定の閾値以下の場合にＳｐＯ２値の安定度が高いと判定してもよい。なお、この判定値においては、例えば、閾値は赤外光および赤色光の振幅比率の０．５％程度とすればよい。なお、この判定値を算出する場合は、最大値および最小値のうちから、異常値は削除しておくことが好ましい。安定度判定部４３は、例えば、所定の期間内における赤外光および赤色光の振幅比率の平均値を求め、平均値より±５～２０％程度以上外れた値であれば異常値と判断し、判定値の算出には用いないこととすればよい。 Incidentally, the instantaneous SpO 2 values, since those determined by the amplitude ratio of the infrared light and red light, in the calculation of the decision value using the instantaneous SpO 2 value, infrared light instead of the instantaneous SpO 2 value Alternatively, the amplitude ratio of red light may be used, and a similar determination value can be obtained. Therefore, the above description, in the determination using the instantaneous SpO 2 values may be used amplitude ratio of the infrared light and red light, instead of the instantaneous SpO 2 value. Specifically, the stability determination unit 43 may determine that the SpO 2 value is stable when the standard deviation of the amplitude ratio of infrared light and red light is equal to or less than a predetermined threshold value. Further, the difference between the maximum value and the minimum value of the amplitude ratio of infrared light and red light is used as a determination value, and the stability determination unit 43 has high stability of the SpO 2 value when the determination value is equal to or less than a predetermined threshold value. May be determined. In this determination value, for example, the threshold value may be about 0.5% of the amplitude ratio of infrared light and red light. When calculating the determination value, it is preferable to delete the abnormal value from the maximum value and the minimum value. For example, the stability determination unit 43 obtains an average value of the amplitude ratio of infrared light and red light within a predetermined period, and determines that it is an abnormal value if the value is more than about ± 5 to 20% or more from the average value. It is sufficient not to use it for calculation of the judgment value.
　また、判定対象期間内における、赤外光および赤色光の振幅比率（ｍ点分）について、最小二乗法を用いて一次直線の近似を行い、その一次近似直線における傾きの絶対値を判定値とし、安定度判定部４３はこの判定値が所定の閾値以下の場合にＳｐＯ２値の安定度が高いと判定してもよい。 In addition, for the amplitude ratio (m points) of infrared light and red light within the determination target period, approximation of the linear line is performed using the least square method, and the absolute value of the slope of the linear approximation line is used as the determination value. The stability determination unit 43 may determine that the stability of the SpO 2 value is high when the determination value is equal to or less than a predetermined threshold value.
　なお、安定度判定部４３は、上述の判定と合わせて、判定対象期間内において異常値が所定の割合以上含まれる場合は、ＳｐＯ２値が安定していないと判定してもよい。なお、異常値は、上述と同様に、所定の期間内における赤外光および赤色光の振幅比率の平均値より±５～２０％程度以上外れた値とすればよい。 In addition to the above determination, the stability determination unit 43 may determine that the SpO 2 value is not stable when the abnormal value is included in a predetermined ratio or more in the determination target period. As described above, the abnormal value may be a value that deviates by about ± 5 to 20% or more from the average value of the amplitude ratio of infrared light and red light within a predetermined period.
　次に、表示ＳｐＯ２値を評価して、ＳｐＯ２値の安定度を判定する場合について説明する。表示ＳｐＯ２値によるＳｐＯ２値の安定度の判定は、瞬時ＳｐＯ２値によるＳｐＯ２値の安定度の判定と同様に行えばよい。安定度判定部４３は、表示ＳｐＯ２値によりＳｐＯ２値の安定度を判定する場合は、式４または式５と同様に、標準偏差を用いて判定すればよい。具体的には、安定度判定部４３は、式５において脈波振幅の値を示すｓ（ｋ）およびｓ（ｌ）の代わりに、測定開始からｋ回目およびｌ回目の測定による表示ＳｐＯ２値を用い、判定値を求めればよい。安定度判定部４３は、さらに、瞬時ＳｐＯ２値によるＳｐＯ２値の安定度の判定の場合と同様に、これらの値の判定対象期間内における測定値のうち最大値と最小値との差を判定値としてもよい。なお、この場合は、最大値および最小値のうちから、異常値は削除しておくべきである。例えば、所定の判定期間内における表示ＳｐＯ２値の平均値より±５～２０％程度以上外れた値であれば異常値と判断し、判定値の算出には用いないこととすればよい。 Next, a case where the display SpO 2 value is evaluated to determine the stability of the SpO 2 value will be described. Determination of stability of SpO 2 value according to display SpO 2 values may be performed in the same manner as the determination of the stability of the SpO 2 value according to the instantaneous SpO 2 value. Stability judging unit 43, when determining the stability of the SpO 2 values by the display SpO 2 values, as in the formula 4 or formula 5 may be determined using the standard deviation. Specifically, the stability determination unit 43 replaces s (k) and s (l) indicating the value of the pulse wave amplitude in Equation 5 with the display SpO 2 values obtained by the k-th and l-th measurements from the start of measurement. And the determination value may be obtained. Stability judging unit 43, Further, as with the determination of the stability of the SpO 2 value according to the instantaneous SpO 2 values, the difference between the maximum value and the minimum value among the measured values within the determination period of these values It is good also as a judgment value. In this case, the abnormal value should be deleted from the maximum value and the minimum value. For example, a value that deviates by about ± 5 to 20% or more from the average value of the displayed SpO 2 values within a predetermined determination period may be determined as an abnormal value and not used for calculation of the determination value.
　また、安定度判定部４３は、判定対象期間内における各表示ＳｐＯ２値（ｍ点分）について、最小二乗法を用いて一次直線の近似を行い、その一次近似直線における傾きの絶対値を判定値として求めてもよい。具体的には、安定度判定部４３は、瞬時ＳｐＯ２値によるＳｐＯ２値の安定度の判定と同様に、算出した判定値が、所定の閾値以下の場合にＳｐＯ２値が安定であると判定できる。なお、表示ＳｐＯ２値による判定においては、上述の特許文献１に記載の式１を用いて行ってもよい。 In addition, the stability determination unit 43 performs approximation of the linear line using the least square method for each display SpO 2 value (for m points) within the determination target period, and determines the absolute value of the slope in the linear approximate line. It may be obtained as a value. And specifically, stability judging unit 43, similarly to the determination of the stability of the SpO 2 value according to the instantaneous SpO 2 value, calculated determination value, SpO 2 values when more than a predetermined threshold value is stable Can be judged. Note that the determination based on the display SpO 2 value may be performed using Equation 1 described in Patent Document 1 described above.
　安定度判定部４３は、表示ＳｐＯ２値によるＳｐＯ２値の安定度の判定において、上記判定値を求め、それらの値が所定の閾値以下の場合にＳｐＯ２値が安定であると判定すればよい。また、安定度判定部４３は、判定対象期間内において、異常値が所定の割合以上含まれる場合は、ＳｐＯ２値は安定ではないと判定してもよい。なお、異常値としては、上述と同様に、所定の期間内における表示ＳｐＯ２値の平均値を求め、平均値より±５～２０％程度以上外れた値とすればよい。 Stability judging unit 43, in the judgment of the stability of the SpO 2 value according to display SpO 2 values, determined the determination value, it is determined that the SpO 2 value when their value is less than the predetermined threshold value is stable Good. Further, the stability determination unit 43 may determine that the SpO 2 value is not stable when the abnormal value is included in a predetermined ratio or more within the determination target period. As the abnormal value, the average value of the display SpO 2 values within a predetermined period may be obtained as described above, and the average value may be a value deviated by about ± 5 to 20% or more.
　上述した判定値を用いて、安定度判定部４３は、信号成分および表示ＳｐＯ２値によりＳｐＯ２値の安定度を判定し、両方の安定度が高い場合、すなわち信号成分および表示ＳｐＯ２値の両方を評価し、それらが共に所定の評価基準を満たす場合に、ＳｐＯ２値が安定したと判定して、表示制御部４４は表示部６に最新の表示ＳｐＯ２値を固定表示させる。具体的には、図３に示すフローチャートで表される。図３は、安定度判定を示すフローチャートである。まず、測定部２が測定を行う（Ｓ１）。制御部４は測定部２で取得された生体情報信号を解析処理し、受光部２２において受光された、信号成分である各光の光量や脈波振幅、赤外光と赤色光との振幅比率、瞬時ＳｐＯ２値等を算出する（Ｓ２）。さらに、瞬時ＳｐＯ２値を基に、表示ＳｐＯ２値を算出し（Ｓ３）、表示部６に表示ＳｐＯ２値を表示させる（Ｓ４）。 Using the determination value as described above, the stability decision unit 43, the signal component and the display SpO 2 values determined the stability of the SpO 2 values, when there is a high both stability, i.e. the signal components and the display SpO 2 value When both are evaluated and both satisfy the predetermined evaluation criteria, it is determined that the SpO 2 value is stable, and the display control unit 44 causes the display unit 6 to display the latest display SpO 2 value in a fixed manner. Specifically, it is represented by the flowchart shown in FIG. FIG. 3 is a flowchart showing stability determination. First, the measurement unit 2 performs measurement (S1). The control unit 4 performs an analysis process on the biological information signal acquired by the measurement unit 2, and the light amount and pulse wave amplitude of each light that is a signal component received by the light receiving unit 22, the amplitude ratio of infrared light and red light. Then, the instantaneous SpO 2 value and the like are calculated (S2). Further, the display SpO 2 value is calculated based on the instantaneous SpO 2 value (S3), and the display SpO 2 value is displayed on the display unit 6 (S4).
　次に、安定度判定部４３は、信号成分である受光部２２において受光された各光の光量や脈波振幅、赤外光と赤色光との振幅比率および瞬時ＳｐＯ２値の少なくともいずれかを用いた判定値ＤＳ１に基づくＳｐＯ２値の安定度判定を行う。具体的には、まず、安定度判定部４３は、現在の値および現在から一定期間過去にさかのぼった間のデータを記憶部５から読み出し、それらを基に判定値ＤＳ１を算出する（Ｓ５）。そして、安定度判定部４３は、判定値ＤＳ１が所定の閾値ＴＨ１以下であるか否かを評価する（Ｓ６）。判定値ＤＳ１が閾値ＴＨ１以下でなければ、再びステップＳ１に戻り、判定値ＤＳ１が閾値ＴＨ１以下であれば、安定度判定部４３は、表示ＳｐＯ２値を用いた判定値ＤＳ２に基づくＳｐＯ２値の安定度判定を行う。具体的には、まず、安定度判定部４３は、現在の値および現在から一定期間過去にさかのぼった間のデータを記憶部５から読み出し、それらを基に判定値ＤＳ２を算出する（Ｓ７）。そして、安定度判定部４３は、判定値ＤＳ２が所定の閾値ＴＨ２以下であるか否かを評価する（Ｓ８）。判定値ＤＳ２が閾値ＴＨ２以下でなければ、再びステップＳ１に戻り、判定値ＤＳ２が閾値ＴＨ２以下であれば、表示制御部４４は表示部６に、最新の表示値すなわち現在表示中のＳｐＯ２値を固定して表示させる（Ｓ９）。なお、固定表示とした後は、測定を行わないこととすればよい。ここで、パルスオキシメータ１００が、ブザー、振動装置またはＬＥＤ（Light　Emitting　Diode：発光ダイオード）等を備えておくこととし、固定表示された場合は、音、振動、光により、操作者にＳｐＯ２値が安定したことを報知する（Ｓ１０）。 Next, the stability determination unit 43 determines at least one of the light amount and pulse wave amplitude of each light received by the light receiving unit 22 as a signal component, the amplitude ratio between infrared light and red light, and the instantaneous SpO 2 value. SpO 2 value stability determination is performed based on the determination value DS 1 used. Specifically, first, stability judging unit 43 reads the data while going back the current value and the current in a predetermined period past from the storage unit 5, and calculates the determination value DS 1 based on them (S5) . The stability judging unit 43, the determination value DS 1 To assess whether a predetermined threshold TH 1 or less (S6). If the determination value DS 1 is not less than or equal to the threshold value TH 1 , the process returns to step S1 again. If the determination value DS 1 is less than or equal to the threshold value TH 1 , the stability determination unit 43 determines the determination value DS 2 using the display SpO 2 value. SpO 2 value stability determination based on Specifically, first, stability judging unit 43 reads the data while going back the current value and the current in a predetermined period past from the storage unit 5, to calculate a decision value DS 2 based on them (S7) . The stability judging unit 43, the determination value DS 2 To assess whether a predetermined threshold TH 2 below (S8). If the determination value DS 2 is not the threshold TH 2 or less, process returns to step S1, if the determination value DS 2 the threshold TH 2 or less, on the display unit 6 is a display control unit 44, the latest display value i.e. currently displayed The SpO 2 value is fixed and displayed (S9). Note that after the fixed display, the measurement is not performed. Here, it is assumed that the pulse oximeter 100 includes a buzzer, a vibration device, an LED (Light Emitting Diode), or the like. When the pulse oximeter 100 is fixedly displayed, SpO 2 is transmitted to the operator by sound, vibration, or light. The fact that the value is stable is notified (S10).
　なお、判定値ＤＳ１による判定においては、安定度判定部４３は、例えば、上記で示した判定方法のうち少なくとも１つの判定方法を用いればよい。また、安定度判定部４３は、１つの判定値を用いることにより行ってもよいし、複数の判定値を用いて判定を行ってもよい。さらに、複数の判定値を用いる場合は、安定度判定部４３は、判定に用いた複数の判定値のすべてが閾値以下でなければＳｐＯ２値が安定ではないと判定してもよいし、所定の数または所定の割合の判定値が閾値以下であればＳｐＯ２値が安定であると判断することとしてもよい。 In the determination by the determination value DS 1, stability judging unit 43, for example, may be used at least one determination method of the determination method indicated above. Moreover, the stability determination part 43 may perform by using one determination value, and may perform determination using a some determination value. Furthermore, when using a plurality of determination values, the stability determination unit 43 may determine that the SpO 2 value is not stable unless all of the plurality of determination values used for the determination are equal to or less than the threshold. It is also possible to determine that the SpO 2 value is stable if the number or the determination value of a predetermined ratio is equal to or less than the threshold value.
　また、信号成分安定度および表示安定度のどちらの安定度判定においても、上述したように、各判定値が、設定された所定の閾値以下である場合にはＳｐＯ２値が安定していると判定される。したがって、この閾値が小さいほど厳しい判定であり、閾値が大きいほど緩い判定であるといえる。実施の形態に係るパルスオキシメータ１００において、判定レベル（評価基準）の度合いを段階的に変化させることができることとすればよい。すなわち、安定度判定部４３は、この閾値を段階的に変化させることが可能であることが好ましい。なお、判定レベルが厳しいほど判定に用いる測定値が少なく、判定レベルが緩いほど判定に用いる測定値を多くすればよい。つまり、判定レベルが厳しい（閾値が小さい）ほど、判定対象期間を短くすればよい。これにより、ＳｐＯ２値の安定度が高い場合には、判定レベルを厳しくした設定としておくことで、判定対象期間が短いため、短時間で測定ができる。 Also, in both stability determinations of signal component stability and display stability, as described above, if each determination value is equal to or less than a predetermined threshold value, the SpO 2 value is stable. Determined. Therefore, it can be said that the smaller the threshold value, the more severe the determination, and the larger the threshold value, the gentler the determination. In the pulse oximeter 100 according to the embodiment, the degree of the determination level (evaluation standard) may be changed stepwise. That is, it is preferable that the stability determination unit 43 can change the threshold stepwise. It should be noted that the stricter the determination level, the smaller the measurement value used for the determination, and the lower the determination level, the more the measurement value used for the determination. That is, the determination target period may be shortened as the determination level is stricter (the threshold value is small). Thereby, when the stability of the SpO 2 value is high, since the determination target period is short by setting the determination level to be strict, measurement can be performed in a short time.
　次に、パルスオキシメータ１００の動作について説明する。まず、被験者の手３００にパルスオキシメータ１００を装着し、操作部８を操作して測定を開始する。測定を開始する際には、安定度判定を行いＳｐＯ２値が安定したと判定した場合には固定表示とする安定度判定モードと、ＳｐＯ２値の値にかかわらず連続して測定を続ける連続測定モードとのいずれかを選択できることが好ましい。 Next, the operation of the pulse oximeter 100 will be described. First, the pulse oximeter 100 is attached to the subject's hand 300, and the operation unit 8 is operated to start measurement. When starting measurement, stability determination is performed and if it is determined that the SpO 2 value is stable, a stability determination mode in which the display is fixed, and continuous measurement is continued regardless of the value of the SpO 2 value. It is preferable that one of the measurement modes can be selected.
　測定開始の指示が操作部８から制御部４になされると、測定制御部４１が、発光部２１、受光部２２、Ｉ／Ｖ変換部３１およびＡ／Ｄ変換部３２を制御してＳｐＯ２値等の生体情報の測定が行われる。測定制御部４１は発光部２１を発光させて、その発光タイミングに同期させて受光部２２に、生体情報信号である光電変換信号を取得させる。さらに、受光部２２で取得された光電変換信号は電流信号であって、Ｉ／Ｖ変換部３１により電圧信号に変換され、光電脈波信号としてＡ／Ｄ変換部３２に出力される。測定制御部４１はＡ／Ｄ変換部３２に、この光電脈波信号をアナログからデジタルに変換させる。 When an instruction to start measurement is given from the operation unit 8 to the control unit 4, the measurement control unit 41 controls the light emitting unit 21, the light receiving unit 22, the I / V conversion unit 31, and the A / D conversion unit 32 to perform SpO 2. Measurement of biological information such as values is performed. The measurement control unit 41 causes the light emitting unit 21 to emit light and causes the light receiving unit 22 to acquire a photoelectric conversion signal that is a biological information signal in synchronization with the light emission timing. Further, the photoelectric conversion signal acquired by the light receiving unit 22 is a current signal, is converted into a voltage signal by the I / V conversion unit 31, and is output to the A / D conversion unit 32 as a photoelectric pulse wave signal. The measurement control unit 41 causes the A / D conversion unit 32 to convert the photoelectric pulse wave signal from analog to digital.
　解析処理部４２は、Ａ／Ｄ変換部３２から出力されたデジタルの光電脈波信号に基づき所定の解析を行い、受光部２２において受光された各光の光量や脈波振幅、赤外光と赤色光との振幅比率、瞬時ＳｐＯ２値および表示ＳｐＯ２値等を算出する。表示制御部４４は、解析処理部４２により算出された表示ＳｐＯ２値等を表示部６に表示させる。また、解析処理部４２は、算出した前記各種パラメータを計時情報と共に記憶部５に保存する。なお、記憶部５に保存しておくパラメータは、安定度判定に用いるもののみとすればよい。 The analysis processing unit 42 performs a predetermined analysis based on the digital photoelectric pulse wave signal output from the A / D conversion unit 32, and the light amount and pulse wave amplitude of each light received by the light receiving unit 22 and infrared light. An amplitude ratio with red light, an instantaneous SpO 2 value, a display SpO 2 value, and the like are calculated. The display control unit 44 causes the display unit 6 to display the display SpO 2 value calculated by the analysis processing unit 42. In addition, the analysis processing unit 42 stores the calculated various parameters in the storage unit 5 together with the timing information. The parameters stored in the storage unit 5 may be only those used for stability determination.
　操作部８により安定度判定モードが選択されている場合には、安定度判定部４３は、安定度判定に用いる過去の測定におけるパラメータを記憶部５から読み出し、上述した方法によりＳｐＯ２値の安定度の判定を行う。なお、上述したように、多段階の判定レベルを有することとする場合には、操作者は操作部８により所望とする判定レベルを選択することとすればよい。それにより、安定度判定部４３は所定の判定対象期間内において所定の判定レベルの安定度判定を行う。 When the stability determination mode is selected by the operation unit 8, the stability determination unit 43 reads the parameters in the past measurement used for the stability determination from the storage unit 5, and stabilizes the SpO 2 value by the method described above. Judge the degree. Note that, as described above, in the case of having multi-level determination levels, the operator may select a desired determination level using the operation unit 8. Thereby, the stability determination part 43 performs the stability determination of a predetermined determination level within a predetermined determination target period.
　また、複数の判定レベルを有しないこととした場合には、所定の判定レベルおよび判定対象期間が初期設定されているが、この判定期間内にＳｐＯ２値が安定であると判定されなかった場合には、安定度判定部４３は判定対象期間を延長し、判定を継続することとすればよい。具体的には、例えば、安定度判定部４３が判定レベルを変更することとすればよく、初期設定された判定レベルよりも厳しい判定レベルに変更すればよい。つまり、判定対象期間内にＳｐＯ２値が安定であると判定されない場合は、ＳｐＯ２値が不安定の度合いが高いと判断できるため、さらにＳｐＯ２値の安定度の判定を続けることとし、判定条件をより厳しくすることで、より信頼性の高いＳｐＯ２値の安定度の判定が実現できる。 In addition, when it is determined that there are not a plurality of determination levels, a predetermined determination level and a determination target period are initially set, but the SpO 2 value is not determined to be stable within the determination period. The stability determination unit 43 may extend the determination target period and continue the determination. Specifically, for example, the stability determination unit 43 may change the determination level, and the determination level may be changed to a stricter determination level than the initially set determination level. That is, if it is not determined that the SpO 2 value is stable within the determination target period, it can be determined that the degree of instability of the SpO 2 value is high, and therefore the determination of the stability of the SpO 2 value is further continued. By making the conditions stricter, it is possible to realize a more reliable determination of the stability of the SpO 2 value.
　安定度判定部４３は、ＳｐＯ２値が安定していると判定した場合には、その旨、表示制御部４４に指示を送る。そこで、表示制御部４４は表示部６に最新の表示ＳｐＯ２値を固定表示させる。なお、パルスオキシメータ１００は、ブザー、振動装置またはＬＥＤ等を備えておくこととし、固定表示された場合は、音、振動、光により、操作者に固定表示されたことを知らせる構成としてもよい。このように、ＳｐＯ２値が安定したことを報知することで、操作者は表示部６を見ずとも、ＳｐＯ２値が安定し、固定表示がなされたことを知ることができる。 If the stability determination unit 43 determines that the SpO 2 value is stable, the stability determination unit 43 sends an instruction to that effect to the display control unit 44. Therefore, the display control unit 44 causes the display unit 6 to display the latest display SpO 2 value in a fixed manner. The pulse oximeter 100 may be provided with a buzzer, a vibration device, an LED, or the like, and when fixedly displayed, the pulse oximeter 100 may be configured to notify the operator of the fixed display by sound, vibration, or light. . In this way, by notifying that the SpO 2 value has stabilized, the operator can know that the SpO 2 value has been stabilized and the fixed display has been made without looking at the display unit 6.
　また、表示部６が固定表示を行うと、測定制御部４１は測定を停止することとすればよい。また、電源部７は、一定時間測定がなされないと、自動的に電源供給を停止することとすればよい。これにより、固定表示となってから、一定時間経過した場合には、パルスオキシメータ１００の電源は自動的にオフされるので、省エネルギー効果を有する。なお、自動的に電源がオフされた後に再び使用する場合には、表示部６は自動的にオフした際に固定表示していた表示ＳｐＯ２値を表示するように、表示制御部４４が表示部６を制御することとすればよい。 Further, when the display unit 6 performs fixed display, the measurement control unit 41 may stop the measurement. Moreover, the power supply part 7 should just stop a power supply automatically, if measurement for a fixed time is not made. As a result, the power source of the pulse oximeter 100 is automatically turned off after a fixed time has elapsed since the fixed display has been made, thus providing an energy saving effect. When the display unit 6 is used again after the power is automatically turned off, the display control unit 44 displays the display SpO 2 value that is fixedly displayed when the display unit 6 is automatically turned off. The unit 6 may be controlled.
　このように、本実施の形態のパルスオキシメータ１００によれば、操作者はパルスオキシメータの表示を見続けることなく、ＳｐＯ２値が安定した場合の値を読み取ることができる。また、ＳｐＯ２値の安定度の判定の信頼性が高いことから、固定表示された値はＳｐＯ２値の変動が少ない状態での値であって、正しい測定値であるといえる。したがって、本実施の形態のパルスオキシメータ１００により、操作者はＳｐＯ２値を正しく測定することができる。 Thus, according to the pulse oximeter 100 of the present embodiment, the operator can read the value when the SpO 2 value is stable without continuing to look at the display of the pulse oximeter. Moreover, since the reliability of the determination of the stability of the SpO 2 value is high, it can be said that the fixedly displayed value is a value in a state where the fluctuation of the SpO 2 value is small and is a correct measured value. Therefore, the pulse oximeter 100 according to the present embodiment allows the operator to correctly measure the SpO 2 value.
　なお、ＳｐＯ２値の安定度の判定は、上記のように表示安定度および信号安定度に基づいて行う以外に、他の方法でもよい。例えば、ＳｐＯ２値の安定度の判定を、信号安定度に基づいてのみ行ってもよい。これにより、測定により得られた値である信号成分に基づいて、ＳｐＯ２値の安定度を判定するので、安定度判定における信頼性が高い。具体的には、受光部２２において受光された各光の光量や脈波振幅、赤外光と赤色光との振幅比率および瞬時ＳｐＯ２値および表示ＳｐＯ２値等のうち、少なくとも２つの値が所定の評価基準を満たすか否かを個別に評価し、これらのすべてが評価基準を満たす場合には、ＳｐＯ２値は安定であると判定してもよい。より具体的には、表示ＳｐＯ２値による評価を行わずに、解析処理部４２により算出した信号成分の内、少なくとも２つの値において評価し、これらのすべてが所定の評価基準を満たす場合は、ＳｐＯ２値は安定であると判定してもよい。また、解析処理部４２により算出した、受光部２２において受光された各光の光量や脈波振幅、赤外光と赤色光との振幅比率および瞬時ＳｐＯ２値および表示ＳｐＯ２値等である信号成分のうち、１つの値においてのみ評価し、この値が所定の評価基準を満たす場合は、ＳｐＯ２値は安定であると判定してもよい。これにより、ＳｐＯ２値の安定度の判定における自由度が増す。 The determination of the stability of the SpO 2 value may be performed by another method other than the determination based on the display stability and the signal stability as described above. For example, the determination of the stability of the SpO 2 value may be performed only based on the signal stability. Thus, based on the signal component is the value obtained by the measurement, since determining the stability of the SpO 2 values, reliable in stability judgment. Specifically, at least two values are included among the light amount and pulse wave amplitude of each light received by the light receiving unit 22, the amplitude ratio of infrared light and red light, the instantaneous SpO 2 value, the display SpO 2 value, and the like. Whether or not a predetermined evaluation criterion is satisfied is evaluated individually, and if all of these satisfy the evaluation criterion, it may be determined that the SpO 2 value is stable. More specifically, when evaluation is performed on at least two values of the signal component calculated by the analysis processing unit 42 without performing evaluation based on the display SpO 2 value, and all of these satisfy a predetermined evaluation criterion, The SpO 2 value may be determined to be stable. Further, signals calculated by the analysis processing unit 42, such as the light amount and pulse wave amplitude of each light received by the light receiving unit 22, the amplitude ratio of the infrared light and the red light, the instantaneous SpO 2 value, the display SpO 2 value, and the like. If only one value is evaluated among the components and this value satisfies a predetermined evaluation criterion, the SpO 2 value may be determined to be stable. This increases the degree of freedom in determining the stability of the SpO 2 value.
　ここで、本発明の実施の形態に係るパルスオキシメータ１００の動作の一例について図４を用いて説明する。図４は実施の形態に係るパルスオキシメータの動作の一例を示すフローチャートである。なお、このパルスオキシメータ１００は、瞬時ＳｐＯ２値の安定度および表示ＳｐＯ２値に基づいて、ＳｐＯ２値の安定度を判定する。また、瞬時ＳｐＯ２値の評価については、その最大値と最小値の差に基づいて行う。 Here, an example of the operation of the pulse oximeter 100 according to the embodiment of the present invention will be described with reference to FIG. FIG. 4 is a flowchart showing an example of the operation of the pulse oximeter according to the embodiment. Incidentally, the pulse oximeter 100, based on the stability and display SpO 2 value of the instantaneous SpO 2 value to determine the stability of the SpO 2 values. The evaluation of the instantaneous SpO 2 value is performed based on the difference between the maximum value and the minimum value.
　まず、測定部２が測定を行う（Ｓ１１）。この際に、例えばＣＰＵに備えられているタイマー機能により、判定時間Ｔを計測する。そこで、測定開始時に判定時間Ｔは０に設定され、判定時間の計時が開始される。解析処理部４２は測定部２で取得された生体情報信号を解析処理し、瞬時ＳｐＯ２値を算出する（Ｓ１２）。予め設定された判定対象期間Ｔ０と判定時間Ｔを比較し（Ｓ１３）、ＴがＴ０以下の場合、すなわち判定対象期間Ｔ０が経過していない場合は再びステップＳ１１に戻る。また、判定時間Ｔが判定対象期間Ｔ０よりも大きい場合は、安定度判定部４３が、記憶部５に格納されている、判定対象期間Ｔ０内に算出された瞬時ＳｐＯ２値を読み出し、それらから異常値を削除する（Ｓ１４）。さらに、安定度判定部４３は、異常値が削除された瞬時ＳｐＯ２値における最大値と最小値との差を算出する（Ｓ１５）。なお、瞬時ＳｐＯ２値における最大値と最小値との差が判定値ＤＳ１である。また、安定度判定部４３は、判定対象期間Ｔ０内における表示ＳｐＯ２値の判定値ＤＳ２を上述方法により算出する（Ｓ１６）。なお、判定値ＤＳ２は、例えば、瞬時ＳｐＯ２値と同様に、表示ＳｐＯ２値の最大値と最小値の差としてもよい。 First, the measurement unit 2 performs measurement (S11). At this time, for example, the determination time T is measured by a timer function provided in the CPU. Therefore, the determination time T is set to 0 at the start of measurement, and measurement of the determination time is started. The analysis processing unit 42 performs an analysis process on the biological information signal acquired by the measurement unit 2 and calculates an instantaneous SpO 2 value (S12). The predetermined determination target period T 0 is compared with the determination time T (S13). If T is equal to or less than T 0 , that is, if the determination target period T 0 has not elapsed, the process returns to step S11 again. When the determination time T is longer than the determination target period T 0 , the stability determination unit 43 reads the instantaneous SpO 2 value calculated in the determination target period T 0 and stored in the storage unit 5. An abnormal value is deleted from them (S14). Furthermore, the stability determination unit 43 calculates the difference between the maximum value and the minimum value in the instantaneous SpO 2 value from which the abnormal value is deleted (S15). Here, the difference between the maximum value and the minimum value is the determination value DS 1 at the instant SpO 2 value. Further, stability judging unit 43, a judgment value DS 2 of the display SpO 2 values within the determination target period T 0 is calculated by the above method (S16). The determination value DS 2 is, for example, like the instantaneous SpO 2 value may be a difference between the maximum value and the minimum value of the display SpO 2 values.
　次に、安定度判定部４３は、算出した判定値ＤＳ１が所定の閾値ＴＨ１以下であるか否かを評価する（Ｓ１７）。判定値ＤＳ１が閾値ＴＨ１以下であれば、安定度判定部４３は、表示ＳｐＯ２値を用いた判定値ＤＳ２に基づく評価を行う。具体的には、安定度判定部４３は、判定値ＤＳ２が所定の閾値ＴＨ２以下であるか否かを評価する（Ｓ１８）。判定値ＤＳ２が閾値ＴＨ２以下であれば、表示制御部４４は表示部６に、最新の表示値すなわち現在表示中のＳｐＯ２値を固定表示させ、パルスオキシメータ１００が備える、ブザー、振動装置またはＬＥＤ等の音、振動、光により、操作者にＳｐＯ２値が安定したことを報知し（Ｓ１９）、終了する。 Next, stability judging unit 43, the calculated determination value DS 1 To assess whether a predetermined threshold TH 1 or less (S17). If the determination value DS 1 is the threshold TH 1 or less, the stability determination unit 43 performs evaluation based on the determination value DS 2 using the display SpO 2 values. Specifically, stability judging unit 43, the determination value DS 2 To assess whether a predetermined threshold TH 2 or less (S18). If the determination value DS 2 the threshold TH 2 or less, the display control unit 44 on the display unit 6, the latest display value ie is fixed displays the SpO 2 value currently displayed, comprising a pulse oximeter 100, a buzzer, vibration The operator notifies the operator that the SpO 2 value has been stabilized by sound, vibration, or light from the device or the LED (S19), and the process ends.
　また、ステップＳ１７において、判定値ＤＳ１が閾値ＴＨ１以下でなかった場合およびステップＳ１８において、判定値ＤＳ２が閾値ＴＨ２以下でなかった場合は、固定表示は行われず、表示制御部４４は表示部６に最新の表示ＳｐＯ２値を更新して表示させる（Ｓ２０）。さらに、制御部４は、例えばＣＰＵに備えられているタイマー機能により、測定開始からの時間を計測しておき、測定開始から所定時間が経過しているか否かを判断する（Ｓ２１）。なお、所定時間は、例えば３０秒程度とすればよい。また、この所定時間経過の判断（ステップＳ２１）は省略してもよく、その場合は、安定と判断されなければ、その都度、判定対象期間の延長がなされることとなる。 Further, in step S17, in a case and S18 determination value DS 1 is not the threshold TH 1 or less, if the determination value DS 2 is not the threshold TH 2 below, fixed display is not performed, the display control unit 44 The latest display SpO 2 value is updated and displayed on the display unit 6 (S20). Furthermore, the control unit 4 measures the time from the start of measurement using, for example, a timer function provided in the CPU, and determines whether or not a predetermined time has elapsed since the start of measurement (S21). The predetermined time may be about 30 seconds, for example. Further, the determination of the elapse of the predetermined time (step S21) may be omitted. In this case, if it is not determined to be stable, the determination target period is extended each time.
　測定開始から所定時間が経過している場合は、再びステップＳ１１に戻って測定部２は測定を継続する。また、所定時間が経過していない場合は、安定度判定部４３は判定対象期間をαだけ延長し（Ｓ２２）、次回の安定度判定においては延長された判定対象期間が適用される。また、判定条件も変更される。具体的には、安定度判定部４３は、閾値ＴＨ１および閾値ＴＨ２の値をそれぞれ閾値ＴＨ１２および閾値ＴＨ２２に変更する（Ｓ２３）。そして、再び、ステップＳ１１に戻り、上述の動作を繰り返す。 When the predetermined time has elapsed from the start of measurement, the measurement unit 2 returns to step S11 and continues measurement. If the predetermined time has not elapsed, the stability determination unit 43 extends the determination target period by α (S22), and the extended determination target period is applied in the next stability determination. Also, the determination condition is changed. Specifically, stability judging unit 43 changes the threshold value TH 1 and the threshold TH 2 values of the threshold TH 12 and the threshold value TH 22, respectively (S23). And it returns to step S11 again and repeats the above-mentioned operation.
　このように、本発明の実施の形態に係るパルスオキシメータによれば、より信頼性の高い方法により、ＳｐＯ２値が安定しているか否かの判定を行うことができる。 Thus, according to the pulse oximeter according to the embodiment of the present invention, it is possible to determine whether or not the SpO 2 value is stable by a more reliable method.
　本発明者は、種々検討した結果、上記目的は、以下の本発明により達成されることを見出した。すなわち、本発明に係る一態様に係る酸素飽和度測定装置は、血中の酸素飽和度を測定する装置であって、生体に赤外光および赤色光を照射し、前記生体を経由した光を受光することで生体情報信号を得る測定部と、前記生体情報信号を解析処理して、前記生体情報信号から信号成分を算出する解析処理部と、算出された前記信号成分に基づいて、前記酸素飽和度の安定度を判定する安定度判定部とを備え、前記安定度判定部は、前記信号成分を評価し、前記信号成分が所定の評価基準を満たす場合に、前記酸素飽和度が安定していると判定する。 As a result of various studies, the present inventor has found that the above object can be achieved by the following present invention. That is, the oxygen saturation measuring apparatus according to one aspect of the present invention is an apparatus for measuring oxygen saturation in blood, which irradiates a living body with infrared light and red light and emits light that has passed through the living body. A measurement unit that obtains a biological information signal by receiving light, an analysis processing unit that analyzes the biological information signal and calculates a signal component from the biological information signal, and the oxygen based on the calculated signal component A stability determination unit that determines the stability of the saturation, and the stability determination unit evaluates the signal component, and the oxygen saturation is stabilized when the signal component satisfies a predetermined evaluation criterion. It is determined that
　これにより、表示血中酸素飽和度のように、測定値の平均値等ではなく、測定値である信号成分に基づいて、血中の酸素飽和度の安定度を判定するので、安定度判定における信頼性が高い。 As a result, the stability of the oxygen saturation in the blood is determined based on the signal component that is the measured value, not the average value of the measured value, as in the displayed blood oxygen saturation. High reliability.
　また、上述の酸素飽和度測定装置において、前記信号成分は、前記受光された光の光量成分、前記受光された光の脈波振幅、前記受光された光のうち赤外光と赤色光との振幅比率および瞬時血中酸素飽和度のうち、少なくとも１つを含むことが好ましい。 Further, in the above-described oxygen saturation measuring apparatus, the signal component includes a light amount component of the received light, a pulse wave amplitude of the received light, and infrared light and red light of the received light. It is preferable to include at least one of the amplitude ratio and the instantaneous blood oxygen saturation.
　これにより、測定により得られた値を用いて、血中の酸素飽和度の安定度を判定するので、安定度判定における信頼性が高い。 Thereby, since the stability of the oxygen saturation in the blood is determined using the value obtained by the measurement, the reliability in the stability determination is high.
　また、上述の酸素飽和度測定装置において、前記解析処理部は、前記生体情報信号から複数の信号成分を算出し、前記安定度判定部は、前記複数の信号成分のうち、少なくとも２つの値をそれぞれ個別に評価し、それらのすべてが、所定の評価基準を満たす場合に、前記酸素飽和度が安定していると判定することが好ましい。 In the above-described oxygen saturation measuring apparatus, the analysis processing unit calculates a plurality of signal components from the biological information signal, and the stability determination unit calculates at least two values of the plurality of signal components. It is preferable to evaluate each individually and determine that the oxygen saturation is stable when all of them satisfy a predetermined evaluation criterion.
　これにより、複数の信号成分のうち少なくとも２つの値に基づいて、血中の酸素飽和度の安定度を判定するので、安定度判定における信頼性が高い。 Thereby, since the stability of the oxygen saturation level in the blood is determined based on at least two values of the plurality of signal components, the reliability in the stability determination is high.
　また、上述の酸素飽和度測定装置において、前記解析処理部は、さらに、前記生体情報信号を解析処理して、表示血中酸素飽和度を算出し、前記安定度判定部は、少なくとも１つの前記信号成分および前記表示血中酸素飽和度をそれぞれ個別に評価し、それらのすべてが、所定の評価基準を満たす場合に、前記酸素飽和度が安定していると判定することが好ましい。 In the above oxygen saturation measuring apparatus, the analysis processing unit further analyzes the biological information signal to calculate a displayed blood oxygen saturation, and the stability determination unit includes at least one of the above-described stability determination units. It is preferable to individually evaluate the signal component and the displayed blood oxygen saturation, and determine that the oxygen saturation is stable when all of them satisfy a predetermined evaluation criterion.
　このように、信号成分および表示血中酸素飽和度の両方に基づいて、血中の酸素飽和度の安定度を判定するので、安定度判定における信頼性が高い。 Thus, since the stability of the oxygen saturation level in the blood is determined based on both the signal component and the displayed blood oxygen saturation level, the reliability in the stability determination is high.
　また、上述の酸素飽和度測定装置によれば、さらに、前記表示血中酸素飽和度を表示する表示部を備え、前記表示部は、前記酸素飽和度が安定していると前記安定度判定部が判定した場合に、前記表示血中酸素飽和度の表示を更新しないことが好ましい。 In addition, according to the above-described oxygen saturation measurement apparatus, the oxygen saturation measurement apparatus further includes a display unit that displays the displayed blood oxygen saturation, and the display unit determines that the oxygen saturation is stable when the oxygen saturation is stable. Is determined, it is preferable not to update the display of the displayed blood oxygen saturation.
　このように、血中の酸素飽和度が安定していると判定された場合に、表示血中酸素飽和度の表示を更新しないので、操作者は、表示血中酸素飽和度が固定表示されていることにより、血中の酸素飽和度が安定したことを容易に認識できる。また、その値を読み取ることで、信頼度の高い表示血中酸素飽和度を読み取ることができる。 As described above, when it is determined that the blood oxygen saturation is stable, the display of the displayed blood oxygen saturation is not updated, so that the operator can display the displayed blood oxygen saturation fixedly. Therefore, it can be easily recognized that the oxygen saturation level in the blood is stable. Further, by reading the value, the display blood oxygen saturation with high reliability can be read.
　また、上述の酸素飽和度測定装置によれば、さらに、前記表示血中酸素飽和度を表示する表示部を備え、前記表示部は、前記評価された値のうち、いずれかが所定の評価基準を満たさない場合には、前記解析処理部で算出される前記表示血中酸素飽和度を随時表示し続けることが好ましい。 Further, according to the above-described oxygen saturation measuring apparatus, the oxygen saturation measuring apparatus further includes a display unit that displays the displayed blood oxygen saturation, and the display unit is configured so that any one of the evaluated values is a predetermined evaluation criterion. If not, it is preferable to keep displaying the displayed blood oxygen saturation calculated by the analysis processing unit as needed.
　これにより、血中の酸素飽和度が安定していない場合には、表示部に表示される表示血中酸素飽和度は、測定により得られた値に基づいて随時更新されていく。したがって、操作者は、表示部を見ることで、血中の酸素飽和度が安定していないことを容易に認識できる。 Thereby, when the blood oxygen saturation is not stable, the displayed blood oxygen saturation displayed on the display unit is updated as needed based on the value obtained by the measurement. Therefore, the operator can easily recognize that the oxygen saturation level in the blood is not stable by looking at the display unit.
　また、上述の酸素飽和度測定装置において、前記安定度判定部は、前記受光された光のうち赤外光と赤色光との前記振幅比率または前記瞬時血中酸素飽和度の各値の評価において、判定対象期間内における該各値の最大値と最小値との差に基づいて評価を行うことが好ましい。なお、各値の評価においては、現時点の測定により得られた値と、現時点より過去の測定により得られた値を用いるが、これら評価に用いる値が測定された期間を判定対象期間という。 Moreover, in the above-described oxygen saturation measurement apparatus, the stability determination unit may evaluate each value of the amplitude ratio of the infrared light and the red light or the instantaneous blood oxygen saturation in the received light. The evaluation is preferably performed based on the difference between the maximum value and the minimum value of the respective values within the determination target period. In the evaluation of each value, the value obtained by the current measurement and the value obtained by the past measurement from the current time are used, and the period during which the value used for the evaluation is measured is referred to as a determination target period.
　これにより、より信頼性の高い、血中の酸素飽和度の安定度判定が実現される。 This realizes more reliable determination of the stability of oxygen saturation in blood.
　また、上述の酸素飽和度測定装置において、前記最大値および前記最小値は、前記判定対象期間内における前記各値のうち、異常値を削除した中から選択されることが好ましい。 Further, in the above-described oxygen saturation measuring apparatus, it is preferable that the maximum value and the minimum value are selected from among abnormal values deleted from the respective values within the determination target period.
　このように、各値を評価するための値から異常値が削除されることで、より信頼性の高い、血中の酸素飽和度の安定度判定が実現される。 As described above, the abnormal value is deleted from the value for evaluating each value, thereby realizing a more reliable determination of the stability of oxygen saturation in blood.
　また、上述の酸素飽和度測定装置において、前記異常値は、前記判定対象期間内における前記各値の平均値を基準として定められることが好ましい。 In the above-described oxygen saturation measuring apparatus, it is preferable that the abnormal value is determined based on an average value of the respective values within the determination target period.
　これにより、異常値の判断基準が明確であって、より信頼性の高い、血中の酸素飽和度の安定度判定が実現される。 This makes it possible to realize the determination of the stability of oxygen saturation in the blood with a clear criteria for judging abnormal values and higher reliability.
　また、上述の酸素飽和度測定装置において、前記安定度判定部は、前記受光された光の前記脈波振幅、前記受光された光のうち赤外光と赤色光との前記振幅比率または前記瞬時血中酸素飽和度の各値の評価において、判定対象期間内における該各値の標準偏差の値に基づいて評価を行うことが好ましい。 In the above-described oxygen saturation measurement apparatus, the stability determination unit may include the pulse wave amplitude of the received light, the amplitude ratio of infrared light and red light of the received light, or the instantaneous In the evaluation of each value of blood oxygen saturation, it is preferable to perform the evaluation based on the standard deviation value of each value within the determination target period.
　これにより、より信頼性の高い、血中の酸素飽和度の安定度判定が実現される。 This realizes more reliable determination of the stability of oxygen saturation in blood.
　また、上述の酸素飽和度測定装置において、前記安定度判定部は、前記受光された光のうち赤外光と赤色光との前記振幅比率または前記瞬時血中酸素飽和度の各値において、判定対象期間内における前記各値のうち、異常値の割合が所定の割合以上であれば、前記酸素飽和度は安定していないと判定することが好ましい。 Further, in the above-described oxygen saturation measurement apparatus, the stability determination unit determines the amplitude ratio of infrared light and red light or the instantaneous blood oxygen saturation value in the received light. It is preferable to determine that the oxygen saturation is not stable if the ratio of abnormal values is equal to or greater than a predetermined ratio among the values within the target period.
　これにより、より信頼性の高い、血中の酸素飽和度の安定度判定が実現される。 This realizes more reliable determination of the stability of oxygen saturation in blood.
　また、上述の酸素飽和度測定装置において、前記安定度判定部は、前記受光された光のうち赤外光と赤色光との前記振幅比率または前記瞬時血中酸素飽和度の各値の評価において、判定対象期間内における前記各値から最小二乗法により一次近似直線を求め、前記一次近似直線の傾きの絶対値に基づいて評価を行うことが好ましい。 Moreover, in the above-described oxygen saturation measuring apparatus, the stability determination unit may evaluate each value of the amplitude ratio of the infrared light and the red light or the instantaneous blood oxygen saturation in the received light. It is preferable that a primary approximate line is obtained from the respective values in the determination target period by a least square method and the evaluation is performed based on the absolute value of the slope of the primary approximate line.
　これにより、より信頼性の高い、血中の酸素飽和度の安定度判定が実現される。 This realizes more reliable determination of the stability of oxygen saturation in blood.
　また、上述の酸素飽和度測定装置において、前記安定度判定部は、判定対象期間内に、前記複数の信号成分のいずれかが所定の評価基準を満たさない場合には、前記判定対象期間を延長すると共に、前記評価基準を変更することが好ましい。 In the oxygen saturation measuring apparatus described above, the stability determination unit extends the determination target period when any of the plurality of signal components does not satisfy a predetermined evaluation criterion within the determination target period. In addition, it is preferable to change the evaluation criteria.
　これにより、判定対象期間内に、複数の信号成分のいずれかが所定の評価基準を満たさない場合には評価基準を変更して、判定対象期間を延長して評価を継続することができる。例えば、判定対象期間内に複数の信号成分のいずれかが所定の評価基準を満たさない場合は、血中の酸素飽和度が不安定の度合いが高いと判断できるため、さらに評価を続けることとし、評価基準をより厳しくすればよい。それにより、より信頼性の高い、血中の酸素飽和度の安定度判定が実現される。 Thus, if any of the plurality of signal components does not satisfy the predetermined evaluation standard within the determination target period, the evaluation standard can be changed and the evaluation target period can be extended to continue the evaluation. For example, if any of the plurality of signal components does not meet the predetermined evaluation criteria within the determination target period, it can be determined that the degree of instability of the oxygen saturation in the blood is high, and the evaluation is continued further. The evaluation criteria should be made stricter. Thereby, a more reliable determination of the stability of the oxygen saturation in the blood is realized.
　また、上述の酸素飽和度測定装置において、前記評価基準は、段階的に異なる複数の評価基準を含み、前記評価基準のそれぞれの段階に対応した判定対象期間が存在し、前記安定度判定部は、前記いずれかの評価基準を用いて、該評価基準に対応した前記判定対象期間内に評価することが好ましい。 Further, in the above-described oxygen saturation measuring apparatus, the evaluation criterion includes a plurality of evaluation criteria that are different in stages, and there are determination target periods corresponding to the respective stages of the evaluation criterion, and the stability determination unit includes: Preferably, the evaluation is performed within the determination target period corresponding to the evaluation criterion by using any one of the evaluation criteria.
　これにより、安定度の状況に応じて操作者が判定条件を厳しくまたは緩くできる。なお、評価基準に応じて判定対象期間の長さが変化するので、酸素飽和度の安定度判定における信頼性のレベルは維持できる。例えば、評価基準が厳しい場合は、判定対象期間を短くすればよい。したがって、血中の酸素飽和度の安定度が高い場合は評価基準を厳しくし、それにより判定対象期間が短くなることから、安定度の判定の信頼性が低下することなく測定時間を短縮できる。 This allows the operator to tighten or loosen the judgment conditions depending on the stability situation. In addition, since the length of the determination target period changes according to the evaluation criterion, the level of reliability in determining the stability of the oxygen saturation can be maintained. For example, when the evaluation standard is strict, the determination target period may be shortened. Therefore, when the stability of oxygen saturation in the blood is high, the evaluation criteria are stricter, thereby shortening the determination target period, so that the measurement time can be shortened without lowering the reliability of stability determination.
　また、上述の酸素飽和度測定装置において、前記安定度判定部は、前記受光された光の光量成分および前記受光された光の脈波振幅の各値の評価において、前記各値の大きさに応じて、判定対象期間を変更することが好ましい。 Further, in the above-described oxygen saturation measurement apparatus, the stability determination unit may determine the magnitude of each value in the evaluation of each value of the light amount component of the received light and the pulse wave amplitude of the received light. Accordingly, it is preferable to change the determination target period.
　これにより、ＳＮ比を考慮して、より信頼性の高い、血中の酸素飽和度の安定度判定が実現される。例えば、受光された光の光量成分および受光された光の脈波振幅の各値が大きいほどＳＮ比が良くなり、血中の酸素飽和度の安定度は高いと判定される。そこで、各値が大きいほど、判定対象期間を短くすればよい。 This makes it possible to determine the stability of oxygen saturation in the blood with higher reliability in consideration of the S / N ratio. For example, it is determined that the greater the respective values of the light intensity component of the received light and the pulse wave amplitude of the received light, the better the S / N ratio and the higher the stability of oxygen saturation in the blood. Therefore, the determination target period may be shortened as each value increases.
　また、上述の酸素飽和度測定装置において、前記安定度判定部が、前記血中酸素飽和度が安定であると判定した場合は、前記酸素飽和度が安定であることの報知を行うことが好ましい。 Moreover, in the above-mentioned oxygen saturation measuring apparatus, when the stability determination unit determines that the blood oxygen saturation is stable, it is preferable to notify that the oxygen saturation is stable. .
　これにより、操作者は血中の酸素飽和度が安定したことを容易に認識できる。 Thereby, the operator can easily recognize that the oxygen saturation in the blood is stable.
　この出願は、２００８年４月３０日に出願された日本国特許出願特願２００８－１１８７７２を基礎とするものであり、その内容は、本願に含まれるものである。 This application is based on Japanese Patent Application No. 2008-118772 filed on Apr. 30, 2008, the contents of which are included in this application.
　本発明を表現するために、上述において図面を参照しながら実施形態を通して本発明を適切且つ十分に説明したが、当業者であれば上述の実施形態を変更および／または改良することは容易に為し得ることであると認識すべきである。したがって、当業者が実施する変更形態または改良形態が、請求の範囲に記載された請求項の権利範囲を離脱するレベルのものでない限り、当該変更形態または当該改良形態は、当該請求項の権利範囲に包括されると解釈される。 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.

Claims (16)

  1. 　血中の酸素飽和度を測定する装置であって、
    　生体に赤外光および赤色光を照射し、前記生体を経由した光を受光することで生体情報信号を得る測定部と、
    　前記生体情報信号を解析処理して、前記生体情報信号から信号成分を算出する解析処理部と、
    　算出された前記信号成分に基づいて、前記酸素飽和度の安定度を判定する安定度判定部とを備え、
    　前記安定度判定部は、前記信号成分を評価し、前記信号成分が所定の評価基準を満たす場合に、前記酸素飽和度が安定していると判定することを特徴とする、酸素飽和度測定装置。     A device for measuring oxygen saturation in blood,
    A measurement unit that irradiates a living body with infrared light and red light, and receives a light via the living body to obtain a biological information signal;
    Analyzing the biological information signal and calculating a signal component from the biological information signal;
    A stability determination unit that determines the stability of the oxygen saturation based on the calculated signal component;
    The stability determination unit evaluates the signal component, and determines that the oxygen saturation is stable when the signal component satisfies a predetermined evaluation criterion. .
  2. 　前記信号成分は、前記受光された光の光量成分、前記受光された光の脈波振幅、前記受光された光のうち赤外光と赤色光との振幅比率および瞬時血中酸素飽和度のうち、少なくとも１つを含むことを特徴とする、請求項１に記載の酸素飽和度測定装置。 The signal component includes a light amount component of the received light, a pulse wave amplitude of the received light, an amplitude ratio between infrared light and red light of the received light, and an instantaneous blood oxygen saturation level. The oxygen saturation measuring device according to claim 1, comprising at least one.
  3. 　前記解析処理部は、前記生体情報信号から複数の信号成分を算出し、
    　前記安定度判定部は、前記複数の信号成分のうち、少なくとも２つの値をそれぞれ個別に評価し、それらのすべてが、所定の評価基準を満たす場合に、前記酸素飽和度が安定していると判定することを特徴とする、請求項１に記載の酸素飽和度測定装置。     The analysis processing unit calculates a plurality of signal components from the biological information signal,
    The stability determination unit individually evaluates at least two values of the plurality of signal components, and when all of them satisfy a predetermined evaluation criterion, the oxygen saturation is stable. The oxygen saturation measuring device according to claim 1, wherein the oxygen saturation measuring device is determined.
  4. 　前記解析処理部は、さらに、前記生体情報信号を解析処理して、表示血中酸素飽和度を算出し、
    　前記安定度判定部は、少なくとも１つの前記信号成分および前記表示血中酸素飽和度をそれぞれ個別に評価し、それらのすべてが、所定の評価基準を満たす場合に、前記酸素飽和度が安定していると判定することを特徴とする、請求項１に記載の酸素飽和度測定装置。     The analysis processing unit further analyzes the biological information signal to calculate a displayed blood oxygen saturation level,
    The stability determination unit individually evaluates at least one of the signal components and the displayed blood oxygen saturation, and when all of them satisfy a predetermined evaluation criterion, the oxygen saturation is stable. The oxygen saturation measuring device according to claim 1, wherein the oxygen saturation measuring device is determined to be.
  5. 　さらに、前記表示血中酸素飽和度を表示する表示部を備え、
    　前記表示部は、前記酸素飽和度が安定していると前記安定度判定部が判定した場合に、前記表示血中酸素飽和度の表示を更新しないことを特徴とする、請求項４に記載の酸素飽和度測定装置。     And a display unit for displaying the displayed blood oxygen saturation level.
    5. The display unit according to claim 4, wherein the display unit does not update the display of the displayed blood oxygen saturation when the stability determination unit determines that the oxygen saturation is stable. 6. Oxygen saturation measuring device.
  6. 　さらに、前記表示血中酸素飽和度を表示する表示部を備え、
    　前記表示部は、前記評価された値のうち、いずれかが所定の評価基準を満たさない場合には、前記解析処理部で算出される前記表示血中酸素飽和度を随時表示し続けることを特徴とする、請求項４に記載の酸素飽和度測定装置。     And a display unit for displaying the displayed blood oxygen saturation level.
    The display unit continues to display the displayed blood oxygen saturation calculated by the analysis processing unit as needed when any of the evaluated values does not satisfy a predetermined evaluation criterion. The oxygen saturation measuring apparatus according to claim 4.
  7. 　前記安定度判定部は、前記受光された光のうち赤外光と赤色光との前記振幅比率または前記瞬時血中酸素飽和度の各値の評価において、判定対象期間内における該各値の最大値と最小値との差に基づいて評価を行うことを特徴とする、請求項２に記載の酸素飽和度測定装置。 In the evaluation of each value of the amplitude ratio of the infrared light and the red light or the instantaneous blood oxygen saturation in the received light, the stability determination unit determines the maximum of each value within the determination target period. 3. The oxygen saturation measuring apparatus according to claim 2, wherein the evaluation is performed based on a difference between the value and the minimum value.
  8. 　前記最大値および前記最小値は、前記判定対象期間内における前記各値のうち、異常値を削除した中から選択されることを特徴とする、請求項７に記載の酸素飽和度測定装置。 The oxygen saturation measuring apparatus according to claim 7, wherein the maximum value and the minimum value are selected from among the respective values within the determination target period from which abnormal values are deleted.
  9. 　前記異常値は、前記判定対象期間内における前記各値の平均値を基準として定められることを特徴とする、請求項８に記載の酸素飽和度測定装置。 The oxygen saturation measuring apparatus according to claim 8, wherein the abnormal value is determined with reference to an average value of the values in the determination target period.
  10. 　前記安定度判定部は、前記受光された光の前記脈波振幅、前記受光された光のうち赤外光と赤色光との前記振幅比率または前記瞬時血中酸素飽和度の各値の評価において、判定対象期間内における該各値の標準偏差の値に基づいて評価を行うことを特徴とする、請求項２に記載の酸素飽和度測定装置。 In the evaluation of the pulse wave amplitude of the received light, the amplitude ratio of infrared light to red light of the received light, or each value of the instantaneous blood oxygen saturation, the stability determination unit 3. The oxygen saturation measuring apparatus according to claim 2, wherein the evaluation is performed based on a standard deviation value of each value within the determination target period.
  11. 　前記安定度判定部は、前記受光された光のうち赤外光と赤色光との前記振幅比率または前記瞬時血中酸素飽和度の各値において、判定対象期間内における前記各値のうち、異常値の割合が所定の割合以上であれば、前記酸素飽和度は安定していないと判定することを特徴とする、請求項２に記載の酸素飽和度測定装置。 The stability determination unit is configured to determine whether the amplitude ratio of infrared light and red light or the instantaneous blood oxygen saturation value among the received light is abnormal among the values in the determination target period. The oxygen saturation measuring apparatus according to claim 2, wherein if the value ratio is equal to or greater than a predetermined ratio, it is determined that the oxygen saturation is not stable.
  12. 　前記安定度判定部は、前記受光された光のうち赤外光と赤色光との前記振幅比率または前記瞬時血中酸素飽和度の各値の評価において、判定対象期間内における前記各値から最小二乗法により一次近似直線を求め、前記一次近似直線の傾きの絶対値に基づいて評価を行うことを特徴とする、請求項２に記載の酸素飽和度測定装置。 In the evaluation of each value of the amplitude ratio of the infrared light and the red light or the instantaneous blood oxygen saturation level among the received light, the stability determination unit determines the minimum from each value in the determination target period. The oxygen saturation measuring apparatus according to claim 2, wherein a primary approximate line is obtained by a square method, and evaluation is performed based on an absolute value of a slope of the primary approximate line.
  13. 　前記安定度判定部は、判定対象期間内に、前記複数の信号成分のいずれかが所定の評価基準を満たさない場合には、前記判定対象期間を延長すると共に、前記評価基準を変更することを特徴とする、請求項１に記載の酸素飽和度測定装置。 The stability determination unit extends the determination target period and changes the evaluation reference when any of the plurality of signal components does not satisfy a predetermined evaluation reference within the determination target period. The oxygen saturation measuring device according to claim 1, characterized in that it is characterized in that
  14. 　前記評価基準は、段階的に異なる複数の評価基準を含み、
    　前記評価基準のそれぞれの段階に対応した判定対象期間が存在し、
    　前記安定度判定部は、前記いずれかの評価基準を用いて、該評価基準に対応した前記判定対象期間内に評価することを特徴とする、請求項１に記載の酸素飽和度測定装置。     The evaluation criteria includes a plurality of evaluation criteria that differ in stages,
    There is a determination target period corresponding to each stage of the evaluation criteria,
    The oxygen saturation measurement apparatus according to claim 1, wherein the stability determination unit performs evaluation within the determination target period corresponding to the evaluation criterion using any one of the evaluation criteria.
  15. 　前記安定度判定部は、前記受光された光の光量成分および前記受光された光の脈波振幅の各値の評価において、前記各値の大きさに応じて、判定対象期間を変更することを特徴とする、請求項２に記載の酸素飽和度測定装置。 The stability determination unit may change a determination target period according to the magnitude of each value in the evaluation of each value of the light amount component of the received light and the pulse wave amplitude of the received light. The oxygen saturation measuring device according to claim 2, characterized in that it is characterized in that
  16. 　前記安定度判定部が、前記血中酸素飽和度が安定であると判定した場合は、前記酸素飽和度が安定であることの報知を行うことを特徴とする、請求項１に記載の酸素飽和度測定装置。 2. The oxygen saturation according to claim 1, wherein when the stability determination unit determines that the blood oxygen saturation is stable, the oxygen saturation according to claim 1 is notified that the oxygen saturation is stable. Degree measuring device.
PCT/JP2009/058280 2008-04-30 2009-04-27 Device for measuring oxygen saturation degree WO2009133851A1 (en)

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EP3473171A4 (en) * 2016-06-15 2020-06-17 Shenzhen Mindray Bio-Medical Electronics Co., Ltd. Method for calculating physiological parameters and corresponding medical equipment
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JP7458869B2 (en) 2020-04-09 2024-04-01 日本光電工業株式会社 Biosignal processing device, biosignal processing program, and biosignal processing method

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WO2014050945A1 (en) * 2012-09-28 2014-04-03 シスメックス株式会社 Non-invasive living body measurement device
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JP7458869B2 (en) 2020-04-09 2024-04-01 日本光電工業株式会社 Biosignal processing device, biosignal processing program, and biosignal processing method

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