Monitoring device, processing device, and computer program

Abstract

To shorten a waiting time until values are displayed while suppressing fine fluctuations in values of biological parameters displayed on a display.SOLUTION: A processing device 11 receives a first intensity signal S1, a second intensity signal S2, and a third intensity signal S3, which are acquired in different manners through a sensor 30 attached to a subject. The processing device 11 calculates a measured value Sm of SpO2 on the basis of the first intensity signal S1 and the second intensity signal S2. The processing device 11 calculates an estimated value Se of SpO2 on the basis of the first intensity signal S1 or the second intensity signal S2 and the third intensity signal S3. The processing device 11 calculates a time movement average value Sa of SpO2 on the basis of the measured value Sm and the estimated value Se, and displays the time movement average value on a display.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to an apparatus and method for monitoring a time-moving average value of a biological parameter of a subject based on a signal acquired from a sensor attached to the subject. The present disclosure also relates to a processing device for displaying the time-moving average value on a display, and a computer program executable by a processor installed in the processing device. [Background technology]

[0002] Patent Document 1 discloses a pulse oximeter that calculates the concentration of a light-absorbing substance in the blood of a subject as an example of a biological parameter. A plurality of periodically calculated concentration values ​​are subjected to time-moving averaging processing, and are then displayed on a display with small fluctuations suppressed (the stability of the displayed value is increased). The greater the number of concentration values ​​(number of intervals) subjected to time-moving averaging processing, the greater the stability of the displayed value, but the longer the waiting time until the value is displayed. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 07-171139 Summary of the Invention [Problem to be solved by the invention]

[0004] There is a demand for reducing the waiting time until the value of a biological parameter shown on a display while suppressing small fluctuations in the value. [Means for solving the problem]

[0005] One example aspect provided by the present disclosure is a monitoring device, comprising: an interface that receives a signal obtained from a sensor attached to the subject; a processor for calculating a time-moving average value of a biological parameter of the subject based on the signal; a display that displays the time moving average value; It is equipped with the signals include a first signal and a second signal obtained in different ways; The processor: calculating a value of the biological parameter based on the first signal; calculating an estimate of the biological parameter based on the first signal and the second signal; The time moving average value is calculated based on the value of the biological parameter and the estimated value of the biological parameter.

[0006] One example aspect provided by the present disclosure is a processing device that displays, on a display, a time-moving average value of a biological parameter of a subject calculated based on a signal acquired from a sensor attached to the subject, the processing device comprising: an interface that accepts data corresponding to the signal; a processor that calculates the time moving average value based on the data; It is equipped with the signals include a first signal and a second signal obtained in different ways; The processor: calculating a value of the biological parameter based on data corresponding to the first signal; calculating an estimate of the biological parameter based on data corresponding to the first signal and data corresponding to the second signal; The time moving average value is calculated based on the value of the biological parameter and the estimated value of the biological parameter.

[0007] One example aspect provided by the present disclosure is a computer program executable by a processor included in a processing device that displays, on a display, a time-moving average value of a biological parameter of a subject calculated based on a signal acquired from a sensor attached to the subject, the computer program comprising: When executed, the processing device: receiving data corresponding to the signal; Calculating the time moving average value based on the data; It is equipped with the signals include a first signal and a second signal obtained in different ways; The processing device includes: calculating a value of the biological parameter based on data corresponding to the first signal; calculating an estimate of the biological parameter based on data corresponding to the first signal and data corresponding to the second signal; The time moving average value is calculated based on the value of the biological parameter and the estimated value of the biological parameter.

[0008] One exemplary embodiment provided by the present disclosure is a method for monitoring a biological parameter of a subject, comprising: receiving a first signal and a second signal acquired in different manners through a sensor attached to the subject; calculating a value of the biological parameter of the subject based on the first signal; calculating an estimate of the biological parameter based on the first signal and the second signal; calculating a time moving average value of the biological parameter based on the value of the biological parameter and the estimated value of the biological parameter; The time moving average value is displayed on a display.

[0009] According to the configurations of the above-described embodiments, the value and estimated value of the biological parameter are calculated each time the first signal and the second signal are acquired, thereby increasing the apparent number of biological parameter values ​​acquired per unit time. In other words, the time required to secure the number of sections of the biological parameter necessary to calculate the desired moving time average value can be reduced. Therefore, the waiting time until the value of the biological parameter displayed on the display is reduced while suppressing minute fluctuations in the value. [Brief explanation of the drawings]

[0010] [Figure 1]1 illustrates a functional configuration of a pulse oximeter according to an embodiment. [Figure 2] 2 illustrates the operation of the pulse oximeter of FIG. 1; [Figure 3] 3 illustrates the calculation process of the time moving average value in FIG. 2; [Figure 4] 10 illustrates a calculation process of a time moving average value according to a comparative example. DETAILED DESCRIPTION OF THE INVENTION

[0011] An example embodiment will be described in detail below with reference to the accompanying drawings. FIG. 1 illustrates the functional configuration of a pulse oximeter 10 according to an example embodiment. The pulse oximeter 10 is a device that measures the percutaneous arterial oxygen saturation (SpO2) of a subject 20. SpO2 indicates the ratio of oxyhemoglobin to the amount of hemoglobin capable of transporting oxygen. Oxyhemoglobin is an example of a light-absorbing substance in blood. SpO2 is an example of a blood light-absorbing substance concentration and a biological parameter. The pulse oximeter 10 is an example of a monitoring device.

[0012] The pulse oximeter 10 includes a processing unit 11 and a display 12. The processing unit 11 is configured to cause the display 12 to display a time-moving average value of SpO2 based on a signal acquired from a sensor 30 attached to the subject 20.

[0013] As illustrated in FIG. 2, the sensor 30 includes a first light-emitting unit 311, a second light-emitting unit 312, and a third light-emitting unit 313.

[0014] The first light-emitting unit 311 is configured to emit a first light having a first wavelength λ1. An example of the first wavelength λ1 is an infrared wavelength such as 880 nm.

[0015] The second light-emitting unit 312 is configured to emit second light having a second wavelength λ2. The second wavelength λ2 is different from the first wavelength λ1. Examples of the second wavelength λ2 include red wavelengths such as 630 nm and 660 nm.

[0016] The third light-emitting unit 313 is configured to emit third light having a third wavelength λ3. The third wavelength λ3 is different from both the first wavelength λ1 and the second wavelength λ2. An example of the third wavelength λ3 is an infrared wavelength such as 940 nm.

[0017] Each of first light-emitting section 311, second light-emitting section 312, and third light-emitting section 313 includes a semiconductor light-emitting element capable of emitting light of a predetermined wavelength. Examples of semiconductor light-emitting elements include light-emitting diodes (LEDs), laser diodes, and EL elements.

[0018] The sensor 30 includes a light receiving unit 32. The light receiving unit 32 includes optical sensors sensitive to the first wavelength λ1, the second wavelength λ2, and the third wavelength λ3, respectively. Examples of the optical sensor include a photodiode, a phototransistor, and a photoresistor.

[0019] The light receiving unit 32 is configured to output a first intensity signal S1 corresponding to the intensity I1 of the first light that has passed through the body tissue 21 of the subject 20. Similarly, the light receiving unit 32 is configured to output a second intensity signal S2 and a third intensity signal S3 that correspond to the intensity I2 of the second light and the intensity I3 of the third light, respectively, that have passed through the body tissue 21.

[0020] Therefore, the first intensity signal S1, the second intensity signal S2, and the third intensity signal S3 are multiple signals acquired in different manners. In this case, the expression "different manners" means that the wavelengths of the light emitted toward the body tissue 21 are different. Each of the first intensity signal S1, the second intensity signal S2, and the third intensity signal S3 may be an analog signal or a digital signal depending on the specifications of the light receiving unit 32.

[0021] 1, the processing device 11 includes an input interface 111. The input interface 111 is configured as a hardware interface capable of receiving the first intensity signal S1, the second intensity signal S2, and the third intensity signal S3. When each of the first intensity signal S1, the second intensity signal S2, and the third intensity signal S3 is an analog signal, the input interface 111 includes an appropriate conversion circuit including an A / D converter.

[0022] The processing device 11 includes a processor 112. The processor 112 is configured to calculate a time-moving average value of SpO2 of the subject 20 based on the first intensity signal S1, the second intensity signal S2, and the third intensity signal S3. The processing performed by the processor 112 will be described in detail below with reference to FIG. 2.

[0023] Based on the change over time in the first intensity signal S1, the processor 112 acquires an amount of change ΔA1 in the attenuation of the first light that accompanies the pulsation of the blood of the subject 20. The amount of change ΔA1 in the attenuation of the first light is expressed by the following equation. ΔA1=ln[S1 / (S1-ΔS1)]≒ΔS1 / S1 (1) ΔS1 indicates the amount of change in the first intensity signal S1 associated with the pulsation of the blood of the subject 20.

[0024] Similarly, the processor 112 acquires, based on the change over time in the second intensity signal S2, an amount of change ΔA2 in the attenuation of the second light caused by the pulsation of the blood of the subject 20. The amount of change ΔA2 in the attenuation is expressed by the following equation. ΔA2=ln[S2 / (S2-ΔS2)]≒ΔS2 / S2 (2) ΔS2 indicates the amount of change in the second intensity signal S2 associated with the pulsation of the subject's 20 blood.

[0025] Similarly, the processor 112 acquires, based on the change over time in the third intensity signal S3, an amount of change ΔA3 in the attenuation of the third light caused by the pulsation of the blood of the subject 20. The amount of change ΔA3 in the attenuation is expressed by the following equation. ΔA3=ln[S3 / (S3-ΔS3)]≒ΔS3 / S3 (3) ΔS3 indicates the amount of change in the third intensity signal S3 due to the pulsation of the blood of the subject 20.

[0026] The processor 112 is configured to calculate the measured value Sm of SpO2 of the subject 20 based on the amount of change in light attenuation ΔA1 and the amount of change in light attenuation ΔA2. Specifically, the processor 112 is configured to execute the following processing.

[0027] The amount of change in attenuation ΔA1 and the amount of change in attenuation ΔA2 can be expressed by the following equations. ΔA1=ΔAb1+ΔAt1=Eb1·Hb·ΔDb+Σt1·ΔDt (4) ΔA2=ΔAb2+ΔAt2=Eb2·Hb·ΔDb+Σt2·ΔDt (5) E is the extinction coefficient (dl g -1 cm -1 ) Hb represents the blood hemoglobin concentration (g dl -1 ) Σ is the extinction rate (cm -1 ) ΔD represents the thickness change (cm) due to blood pulsation. Subscript b represents blood. Subscript t represents tissue other than blood. Subscript 1 represents the first light. Subscript 2 represents the second light.

[0028] Equations (4) and (5) can be transformed as follows: ΔA1=Eb1·Hb·ΔDb+Σt1·ΔDt =[Eb1+(Σt1·ΔDt) / (Hb·ΔDb)](Hb·ΔDb) =(Eb1+Ex1)(Hb·ΔDb) (6) ΔA2=Eb2·Hb·ΔDb+Σt2·ΔDt =[Eb2+(Σt2·ΔDt) / (Hb·ΔDb)](Hb·ΔDb) =(Eb2+Ex2)(Hb·ΔDb) (7) Here, Ex is a variable replacing (Σt ΔDt) / (Hb ΔDb). The subscript 1 represents the first light. The subscript 2 represents the second light.

[0029] Equations (6) and (7) can be transformed as follows: Eb1+Ex1-ΔA1 / (Hb·ΔDb)=0 (8) Eb2+Ex2-ΔA2 / (Hb·ΔDb)=0 (9)

[0030] Regarding equation (9), the absorption coefficient Eb2 of blood for the second light can be approximated by the absorption coefficient Eb1 of blood for the first light as follows: Eb2=a2·Eb1+b2 (10) where a and b are constants. The subscript 1 represents the first light. The subscript 2 represents the second light.

[0031] Furthermore, Ex2 of the second light can be approximated by Ex1 of the first light as follows: Ex2=α2·Ex1+β2 (11) where α and β are constants. The subscript 1 represents the first light. The subscript 2 represents the second light.

[0032] By rewriting equations (8) and (9) using equations (10) and (11), the following equations are obtained: Eb1+Ex1-ΔA1 / (Hb ΔDb)=0 Eb1-ΔA1 / (Hb·ΔDb)=-Ex1 (12) (a2·Eb1+b2)+(α2·Ex1+β2)-ΔA2 / (Hb·ΔDb)=0 a2·Eb1-ΔA2 / (Hb·ΔDb)=-α2·Ex1-β2-b2 (13)

[0033] Using a statistically obtained constant value as Ex1, the values ​​of the variables Eb1 and HbΔDb can be obtained by calculating the following determinant:

number

[0034] When SpO2 expressed as a percentage is converted into Sm expressed as a decimal, the absorption coefficient Eb1 of the first light is expressed by the following equation. Eb1=Eo1·Sm+Er1(1−Sm) (15) Eo represents the extinction coefficient of oxygenated hemoglobin. Er represents the extinction coefficient of deoxygenated hemoglobin. The subscript 1 represents the first light. Thus, the processor 112 calculates the measured value of SpO2, Sm, using the following formula: Sm=(Eb1-Er1) / (Eo1-Er1) (16)

[0035] It is known that an estimated value ΔA3e of the amount of change in attenuation ΔA3 of the third light can be calculated based on the amount of change in attenuation ΔA1 of the first light and the amount of change in attenuation ΔA2 of the second light. The estimated value ΔA3e can be expressed by the following equation. ΔA3e=ΔAb3+ΔAt3=Eb3·Hb·ΔDb+Σt3·ΔDt (17) As mentioned above, E is the extinction coefficient (dl g -1 cm -1 ) Hb represents the blood hemoglobin concentration (g dl -1 ) Σ is the extinction rate (cm -1 ) ΔD represents the thickness change (cm) due to blood pulsation. The subscript b represents blood. The subscript t represents tissue other than blood. The subscript 3 represents the third light.

[0036] Equation (17) can be transformed as follows: ΔA3e=Eb3·Hb·ΔDb+Σt3·ΔDt =[Eb3+(Σt3·ΔDt) / (Hb·ΔDb)](Hb·ΔDb) =(Eb3+Ex3)(Hb·ΔDb) (18) As mentioned above, Ex is a variable that replaces (Σt·ΔDt) / (Hb·ΔDb). The subscript 3 represents the third light.

[0037] Regarding equation (18), the absorption coefficient of blood for the third light, Eb3, can be approximated by the absorption coefficient of blood for the first light, Eb1, as follows: Eb3=a3·Eb1+b3 (19) As mentioned above, a and b are constants. The subscript 1 represents the first light. The subscript 3 represents the third light.

[0038] Furthermore, the third light Ex3 can be approximated by the first light Ex1 as follows: Ex3=α3·Ex1+β3 (20) where α and β are constants. The subscript 1 represents the first light. The subscript 3 represents the third light.

[0039] By rewriting equation (18) using equations (19) and (20), the following equation is obtained: ΔA3e=[(a3·Eb1+b3)+(α3·Ex1+β3)]Hb·ΔDb (twenty one)

[0040] Therefore, the estimated value ΔA3e can be calculated by substituting the values ​​of Eb1 and Hb·ΔDb obtained through equation (14) into equation (21).

[0041] The above fact means that an estimated value ΔA1e of the amount of change in attenuation ΔA1 of the first light can be calculated based on the amount of change in attenuation ΔA2 of the second light and the amount of change in attenuation ΔA3 of the third light. Similarly, an estimated value ΔA1e of the amount of change in attenuation ΔA1 of the first light can be calculated based on the amount of change in attenuation ΔA2 of the second light and the amount of change in attenuation ΔA3 of the third light. The specific flow of the calculation process is as follows.

[0042] The amount of change in attenuation ΔA2 and the amount of change in attenuation ΔA3 can be expressed by the following equations. ΔA2=ΔAb2+ΔAt2=Eb2·Hb·ΔDb+Σt2·ΔDt (22) ΔA3=ΔAb3+ΔAt3=Eb3·Hb·ΔDb+Σt3·ΔDt (23) E is the extinction coefficient (dl g -1 cm -1 ) Hb represents the blood hemoglobin concentration (g dl -1 ) Σ is the extinction rate (cm -1 ) ΔD represents the thickness change (cm) due to blood pulsation. Subscript b represents blood. Subscript t represents tissue other than blood. Subscript 2 represents the second light. Subscript 3 represents the third light.

[0043] Equations (22) and (23) can be transformed as follows: ΔA2=Eb2·Hb·ΔDb+Σt2·ΔDt =[Eb2+(Σt2·ΔDt) / (Hb·ΔDb)](Hb·ΔDb) =(Eb2+Ex2)(Hb·ΔDb) (24) ΔA3=Eb3·Hb·ΔDb+Σt3·ΔDt =[Eb3+(Σt3·ΔDt) / (Hb·ΔDb)](Hb·ΔDb) =(Eb3+Ex3)(Hb·ΔDb) (25) Here, Ex is a variable replacing (Σt ΔDt) / (Hb ΔDb). The subscript 2 represents the second light. The subscript 3 represents the third light.

[0044] Equations (24) and (25) can be transformed as follows: Eb2+Ex2-ΔA2 / (Hb·ΔDb)=0 (26) Eb3+Ex3-ΔA3 / (Hb·ΔDb)=0 (27)

[0045] With respect to equation (26), the absorption coefficient of blood for the second light, Eb2, can be approximated by the absorption coefficient of blood for the third light, Eb3, as follows: Eb2=a2·Eb3+b2 (28) where a and b are constants. The subscript 2 represents the second light. The subscript 3 represents the third light.

[0046] Furthermore, the second light Ex2 can be approximated by the third light Ex3 as follows: Ex2=α2·Ex3+β2 (29) where α and β are constants. The subscript 2 represents the second light. The subscript 3 represents the third light.

[0047] By rewriting equations (26) and (27) using equations (28) and (29), the following equations are obtained: Eb3 + Ex3 - ΔA3 / (Hb ΔDb) = 0 Eb3-ΔA3 / (Hb·ΔDb)=-Ex3 (30) (a2·Eb3+b2)+(α2·Ex3+β2)-ΔA2 / (Hb·ΔDb)=0 a2·Eb3-ΔA2 / (Hb·ΔDb)=-α2·Ex3-β2-b2 (31)

[0048] Using a statistically obtained constant value for Ex3, the variables Eb3 and HbΔDb can be obtained by calculating the following determinant:

number

[0049] When SpO2, which is expressed as a percentage, is converted into the unit Sm, which is expressed as a decimal, the third light absorption coefficient Eb3 is expressed by the following formula. Eb3=Eo3·Sm+Er3(1−Sm) (33) Eo represents the extinction coefficient of oxygenated hemoglobin. Er represents the extinction coefficient of deoxygenated hemoglobin. The subscript 3 represents the third light. Therefore, the processor 112 calculates the measured value of SpO2, Sm, using the following formula: Sm = (Eb3 - Er3) / (Eo3 - Er3) (34)

[0050] An estimated value ΔA1e of the amount of change in attenuation ΔA1 of the first light can be calculated based on the amount of change in attenuation ΔA2 of the second light and the amount of change in attenuation ΔA3 of the third light. The estimated value ΔA1e can be expressed by the following equation. ΔA1e=ΔAb1+ΔAt1=Eb1·Hb·ΔDb+Σt1·ΔDt (35) As mentioned above, E is the extinction coefficient (dl g -1 cm -1 ) Hb represents the blood hemoglobin concentration (g dl -1 ) Σ is the extinction rate (cm -1 ) ΔD represents the thickness change (cm) due to blood pulsation. The subscript b represents blood. The subscript t represents tissue other than blood. The subscript 1 represents the first light.

[0051] Equation (35) can be transformed as follows: ΔA1e=Eb1·Hb·ΔDb+Σt1·ΔDt =[Eb1+(Σt1·ΔDt) / (Hb·ΔDb)](Hb·ΔDb) =(Eb1+Ex1)(Hb·ΔDb) (36) As mentioned above, Ex is a variable that replaces (Σt·ΔDt) / (Hb·ΔDb). The subscript 1 represents the first light.

[0052] With respect to equation (36), the absorption coefficient of blood for the first light, Eb1, can be approximated by the absorption coefficient of blood for the third light, Eb3, as follows: Eb1=a1·Eb3+b1 (37) As mentioned above, a and b are constants. The subscript 1 represents the first light. The subscript 3 represents the third light.

[0053] Furthermore, the first light Ex1 can be approximated by the third light Ex3 as follows: Ex1=α1·Ex3+β1 (38) where α and β are constants. The subscript 1 represents the first light. The subscript 3 represents the third light.

[0054] By rewriting equation (36) using equations (37) and (38), the following equation is obtained: ΔA1e=[(a1·Eb3+b1)+(α1·Ex3+β1)]Hb·ΔDb (39)

[0055] Therefore, the estimated value ΔA1e can be calculated by substituting the values ​​of Eb3 and Hb·ΔDb obtained through equation (32) into equation (39).

[0056] The first intensity signal S1, the second intensity signal S2, and the third intensity signal S3 are output from the sensor 30 at a predetermined cycle. Each time the first intensity signal S1, the second intensity signal S2, and the third intensity signal S3 are received by the input interface 111, the processor 112 calculates a measured value Sm of SpO2 based on the first intensity signal S1 and the second intensity signal S2, and calculates an estimated value Se of SpO2 based on the third intensity signal S3 and the first intensity signal S1 or the second intensity signal S2. The first intensity signal S1 and the second intensity signal S2 are examples of first signals. The third intensity signal S3 is an example of a second signal.

[0057] 3 illustrates a time series of the thus obtained multiple measured values ​​Sm and multiple estimated values ​​Se of SpO2. Black circles represent measured values ​​Sm, and white circles represent estimated values ​​Se. Processor 112 is configured to sequentially calculate a time-moving average value Sa of SpO2 while moving a window W corresponding to a time length T corresponding to the number of intervals n.

[0058] 1, the processing device 11 includes an output interface 113. The processor 112 is configured to output, from the output interface 113, a control signal CS that causes the calculated time moving average value Sa to be displayed on the display 12. The control signal CS may be an analog signal or a digital signal depending on the specifications of the display 12.

[0059] That is, the output interface 113 is configured as a hardware interface capable of outputting the control signal SC. When the control signal SC is an analog signal, the output interface 113 includes an appropriate conversion circuit including a D / A converter.

[0060] Based on the control signal CS, the display 12 displays the time moving average value Sa of SpO2 calculated successively by the processor 112. The time moving average value Sa is provided for visual confirmation by the user.

[0061] 4 shows a comparative example in which the time-moving average value Sa is calculated based solely on the time series of SpO2 measurement values ​​Sm. In order to suppress small fluctuations in the SpO2 values ​​displayed on display 12, it is necessary to increase the number of values ​​used in the moving average calculation. Therefore, to obtain the same display stability as in the example shown in FIG. 3, it is necessary to ensure the same number of intervals, which increases the time length T of window W. In this case, the waiting time from the start of SpO2 monitoring until the first time-moving average value Sa is displayed on display 12 increases.

[0062] According to the configuration of this embodiment, the measured value Sm and estimated value Se of SpO2 are calculated each time the first intensity signal S1, the second intensity signal S2, and the third intensity signal S3 are acquired, thereby increasing the apparent number of SpO2 values ​​acquired per unit time. In other words, the time required to ensure the number of SpO2 intervals necessary to calculate the desired moving-time average value can be reduced. Therefore, the waiting time until the SpO2 value displayed on the display 12 is displayed can be reduced while suppressing small fluctuations in the value.

[0063] The processor 112 of the processing device 11 having the various functions described above may be realized by a general-purpose microprocessor operating in cooperation with general-purpose memory. Examples of general-purpose microprocessors include a CPU, an MPU, and a GPU. Examples of general-purpose memory include a ROM and a RAM. In this case, a computer program that realizes the various functions described above may be stored in the ROM. The ROM is an example of a non-transitory computer-readable medium that stores a computer program. The general-purpose microprocessor specifies at least a portion of the program stored in the ROM, deploys it on the RAM, and executes the above-described processing in cooperation with the RAM. The computer program may be pre-installed in the general-purpose memory, or may be downloaded from an external server device via a communication network and then installed in the general-purpose memory. In this case, the external server device is an example of a non-transitory computer-readable medium that stores a computer program.

[0064] The processor 112 may be implemented by a dedicated integrated circuit, such as a microcontroller, ASIC, or FPGA, capable of executing the computer program. In this case, the computer program is pre-installed in a memory element included in the dedicated integrated circuit. The memory element is an example of a computer-readable medium that stores a computer program. The processor 112 may also be implemented by a combination of a general-purpose microprocessor and a dedicated integrated circuit.

[0065] The various configurations described above are merely examples for facilitating understanding of the present disclosure. Each configuration example can be appropriately modified or combined with other configurations within the scope of the present disclosure.

[0066] In the above embodiment, the display 12, which displays the calculated time-moving average value Sa of SpO2, is provided as part of the pulse oximeter 10 together with the processing device 11. However, the time-moving average value Sa may be displayed on a display 12A located remote from the processing device 11. The display 12A may be a device installed in a predetermined location or a mobile device that can be carried by a user. In this case, the control signal CS output from the output interface 113 of the processing device 11 is transmitted to the display 12A via a wired or wireless communication network.

[0067] In the above embodiment, the first intensity signal S1, the second intensity signal S2, and the third intensity signal S3 output from the sensor 30 attached to the subject 20 are directly input to the processing device 11. However, the processing device 11 may be located at a location remote from the sensor 30. In this case, the first intensity signal S1, the second intensity signal S2, and the third intensity signal S3 are transmitted to the processing device 11 via a wired or wireless communication network.

[0068] In the above embodiment, SpO2 is calculated as the blood light absorber concentration of the subject 20. However, other blood light absorber concentrations may also be calculated. Examples of other blood light absorbers include carboxyhemoglobin, met hemoglobin, and dyes injected into the blood. In this case, the combination of the first wavelength λ1, the second wavelength λ2, and the third wavelength λ3 is appropriately selected so that the ratio of the blood absorption coefficients of the combinations varies substantially depending on the blood light absorber concentration.

[0069] An electrocardiograph that acquires an electrocardiogram waveform of the subject 20 can be an example of a monitoring device. In this case, the potential of the ST segment in the electrocardiogram waveform is an example of a biological parameter. In this case, the processing device 11 calculates a measurement value of the potential of the ST segment based on a signal corresponding to lead II and a signal corresponding to lead III of the subject 20. Therefore, these signals are an example of a first signal and a second signal. On the other hand, an estimated value of lead I is obtained based on the signal corresponding to lead II and a signal corresponding to lead III, and therefore an estimated value of the potential of the ST segment is obtained. The processing device 11 calculates a time-moving average value of the potential of the ST segment based on the measured and estimated values ​​of the potential.

[0070] A multi-gas (anesthetic gas) monitor that acquires the respiratory waveform of the subject 20 can be an example of a monitoring device. In this case, the gas partial pressure and gas concentration at the end-tidal portion of the respiratory waveform are an example of a biological parameter. In this case, the processing device 11 calculates measured values ​​of the gas partial pressure and gas concentration at the end-tidal portion based on the attenuation of the first light and the attenuation of the second light due to the passage of gas through the breathing circuit connected to the subject 20. Therefore, these signals are an example of a first signal and a second signal. On the other hand, an estimated value of the attenuation of the third light is obtained based on the attenuation of the first light and the attenuation of the second light, thereby obtaining estimated values ​​of the gas partial pressure and gas concentration at the end-tidal portion. The processing device 11 calculates a time-moving average value of the gas partial pressure and gas concentration at the end-tidal portion based on the measured and estimated values ​​of the attenuation.

[0071] When performing multi-gas (anesthetic gas) monitoring to acquire a respiratory waveform and calculating a time moving average value, the processor 112 executes the following process.

[0072] Based on the first intensity signal S1 received by the input interface 111, the processor 112 acquires the attenuation A1 of the first light caused by passing through the gas in the breathing circuit connected to the subject 20. Since the intensity I01 of the first light emitted from the first light-emitting unit 311 is known, the attenuation A1 can be obtained by the following equation. A1=ln(I01 / I1) (40)

[0073] Similarly, the processor 112 obtains the attenuation A2 of the second light caused by passing through the gas in the breathing circuit connected to the subject 20, based on the second intensity signal S2 received by the input interface 111. Since the intensity I02 of the second light emitted from the second light-emitting unit 312 is known, the attenuation A2 can be obtained by the following equation. A2=ln(I02 / I2) (41)

[0074] Similarly, the processor 112 acquires an attenuation A3 of the third light caused by passing through gas in the breathing circuit connected to the subject 20, based on the third intensity signal S3 received by the input interface 111. Since the intensity I03 of the third light emitted from the third light-emitting unit 313 is known, the attenuation A3 can be obtained by the following equation. A3=ln(I03 / I3) (42) [Explanation of symbols]

[0075] 10: Pulse oximeter, 11: Processing device, 111: Input interface, 112: Processor, 12, 12A: Display, S1: First intensity signal, S2: Second intensity signal, S3: Third intensity signal, Sa: Time moving average value of SpO2, Se: Estimated value of SpO2, Sm: Measured value of SpO2, λ1: First wavelength, λ2: Second wavelength, λ3: Third wavelength

Claims

1. an interface that receives a signal obtained from a sensor attached to the subject; a processor for calculating a time-moving average value of a biological parameter of the subject based on the signal; a display that displays the time moving average value; It is equipped with the signals include a first signal and a second signal obtained in different ways; The processor: calculating a value of the biological parameter based on the first signal; calculating an estimate of the biological parameter based on the first signal and the second signal; calculating the time moving average value based on the value of the biological parameter and the estimated value of the biological parameter; Monitoring equipment.

2. The first signal is a first intensity signal corresponding to the intensity of first light having a first wavelength that has passed through biological tissue of the subject; and a second intensity signal corresponding to the intensity of second light having a second wavelength different from the first wavelength that has passed through the biological tissue; and It contains the second signal is a third intensity signal corresponding to the intensity of third light having a third wavelength different from the first wavelength and the second wavelength and having passed through the biological tissue; The biological parameter is transcutaneous arterial oxygen saturation. The monitoring device of claim 1 .

3. A processing device that displays on a display a time-moving average value of a biological parameter of a subject calculated based on a signal acquired from a sensor attached to the subject, an interface that accepts data corresponding to the signal; a processor that calculates the time moving average value based on the data; It is equipped with the signals include a first signal and a second signal obtained in different ways; The processor: calculating a value of the biological parameter based on data corresponding to the first signal; calculating an estimate of the biological parameter based on data corresponding to the first signal and data corresponding to the second signal; calculating the time moving average value based on the value of the biological parameter and the estimated value of the biological parameter; Processing equipment.

4. A computer program executable by a processor mounted in a processing device that displays on a display a time-moving average value of a biological parameter of a subject calculated based on a signal acquired from a sensor attached to the subject, the computer program comprising: When executed, the processing device: receiving data corresponding to the signal; Calculating the time moving average value based on the data; It is equipped with the signals include a first signal and a second signal obtained in different ways; The processing device includes: calculating a value of the biological parameter based on data corresponding to the first signal; calculating an estimate of the biological parameter based on data corresponding to the first signal and data corresponding to the second signal; calculating the time moving average value based on the value of the biological parameter and the estimated value of the biological parameter; Computer program.

5. 1. A method for monitoring a biological parameter of a subject, comprising: receiving a first signal and a second signal acquired in different manners through a sensor attached to the subject; calculating a value of the biological parameter of the subject based on the first signal; calculating an estimate of the biological parameter based on the first signal and the second signal; calculating a time moving average value of the biological parameter based on the value of the biological parameter and the estimated value of the biological parameter; Displaying the time moving average value on a display. Monitoring methods.

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