Processor and computer program

Abstract

To enable monitoring arterial oxygen partial pressure non-invasively and time consecutively.SOLUTION: An input interface 111 receives at least either of first data D1 corresponding to measurement values of arterial oxygen partial pressure and arterial blood oxygen saturation of an object person 20, and second data D2 corresponding to at least one value of arterial blood carbon dioxide partial pressure, arterial blood pH, a body temperature and 2,3-DPG concentration in blood of the object person 20. A processor 112 determines a regulation for converting the arterial blood oxygen saturation of the object person 20 to an estimation value of the arterial oxygen partial pressure of the object person 20 on the basis of at least one of the first data D1 and the second data D2. When the input interface 111 receives third data D3 corresponding to percutaneous arterial oxygen saturation of the object person 20, the processor 112 calculates the estimation value on the basis of the third data D3 and the regulation.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a processing device for monitoring arterial blood oxygen pressure, which is an index of a subject's respiratory function. The present disclosure also relates to a computer program executable by a processor installed in the processing device. [Background technology]

[0002] For example, in acute care, management of the subject's respiratory function is an important factor. Breathing is performed to take in oxygen from the outside air and supply it to the body, so the oxygen content in blood can be one of the indicators of respiratory function. Patent Document 1 discloses a system that also monitors arterial blood oxygen saturation to optimize artificial ventilation. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-538553 A Summary of the Invention [Problem to be solved by the invention]

[0004] There is a need to be able to monitor arterial blood oxygen pressure non-invasively and continuously over time. [Means for solving the problem]

[0005] One embodiment provided by the present disclosure is a processing device, comprising: an input interface for receiving at least one of first data corresponding to actual measured values ​​of arterial blood oxygen partial pressure and arterial blood oxygen saturation of the subject, and second data corresponding to at least one value of arterial blood carbon dioxide partial pressure, arterial blood pH, body temperature, and 2,3-DPG concentration in the blood of the subject; a processor for determining a rule for converting the subject's arterial blood oxygen saturation to an estimate of the subject's arterial blood oxygen partial pressure based on at least one of the first data and the second data; It is equipped with When the input interface receives third data corresponding to the subject's percutaneous arterial oxygen saturation, the processor calculates the estimated value based on the third data and the rule.

[0006] One aspect of the present disclosure provides a computer program executable by a processor installed in a processing device, the computer program comprising: When executed, the processing device: receiving at least one of first data corresponding to actual measured values ​​of arterial blood oxygen partial pressure and arterial blood oxygen saturation of the subject, and second data corresponding to at least one value of arterial blood carbon dioxide partial pressure, arterial blood pH, body temperature, and 2,3-DPG concentration in the blood of the subject; determining a rule for converting the subject's arterial blood oxygen saturation to an estimate of the subject's arterial blood oxygen partial pressure based on at least one of the first data and the second data; Accepting third data corresponding to a percutaneous arterial oxygen saturation level of the subject; The estimated value is calculated based on the third data and the rule.

[0007] According to the configurations of the above-mentioned embodiments, the value of the arterial blood oxygen partial pressure of the subject is estimated using the actual measured value of the percutaneous arterial blood oxygen saturation, which can be obtained continuously and non-invasively, so that the estimated value of the arterial blood oxygen partial pressure of the subject can be continuously monitored without imposing a burden associated with the invasiveness of blood sampling. In addition, the rule for converting the actual measured value of the percutaneous arterial blood oxygen saturation into the estimated value of the arterial blood oxygen partial pressure is determined through a minimum number of blood gas analyses (including zero times) based on the values ​​of the subject's biological parameters that may affect the shift of the oxygen dissociation curve. Therefore, it is possible to obtain an estimated value of the arterial blood oxygen partial pressure that reflects the biological condition of the subject while further reducing the burden that may be imposed on the subject. [Brief description of the drawings]

[0008] [Figure 1] 2 illustrates an example of a functional configuration of a monitoring system according to an embodiment. [Diagram 2] 1 illustrates an oxygen dissociation curve. [Diagram 3] 1 illustrates factors that shift the oxygen dissociation curve. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Exemplary embodiments are described in detail below with reference to the accompanying drawings.

[0010] 1 illustrates an example of a functional configuration of a monitoring system 10 according to an embodiment. The monitoring system 10 has a configuration for monitoring the arterial blood oxygen partial pressure (PaO2) of a subject 20. PaO2 is a value indicating the partial pressure of oxygen contained in arterial blood, and is used as an index indicating the oxygenation state of blood in the lungs as a respiratory function.

[0011] FIG. 2 illustrates the relationship between PaO2 and invasive arterial oxygen saturation (SaO2). This characteristic curve is known as the oxygen dissociation curve. SaO2 is a value that indicates the ratio of hemoglobin contained in arterial blood that is bound to oxygen. SaO2 can be expressed as a percentage. In this example, it is shown to take values ​​ranging from 0, which corresponds to 0%, to 1, which corresponds to 100%.

[0012] By using the oxygen dissociation curve, if the SaO2 value can be obtained, the PaO2 value can be estimated. However, since SaO2 is a value obtained invasively, the obtained PaO2 value is inevitably time-discrete. In addition, since SaO2 is a value obtained invasively, obtaining the PaO2 value multiple times is a burden for the subject.

[0013] Furthermore, it is known that the entire oxygen dissociation curve shifts to the left or right in response to changes in various biological parameters, as shown by the dashed line in Figure 2. Figure 3 illustrates the effect of changes in biological parameters on the shift in the oxygen dissociation curve.

[0014] Examples of biological parameters that shift the oxygen dissociation curve include the affinity of oxygen and hemoglobin in arterial blood, the partial pressure of carbon dioxide in arterial blood (PaCO2), the pH of arterial blood, body temperature (blood temperature), and the concentration of 2,3-DPG (2,3-Diphosphoglycerate) in blood. Note that blood temperature may be estimated based on body temperature measured at other body parts, such as body surface temperature or rectal temperature.

[0015] In view of the fact that SaO2 and SpO2 do not deviate greatly from each other, the inventors of the present application conceived the idea that once a calibrated oxygen dissociation curve is determined taking into account the biological parameters of the subject 20, the calibrated oxygen dissociation curve can be used thereafter to accurately and continuously calculate PaCO2 from the measured value of SpO2 that is obtained non-invasively and continuously over time. The calibrated oxygen dissociation curve is an example of a rule for converting the arterial blood oxygen saturation of the subject 20 into an estimated value of PaO2.

[0016] The following equation (Hill's equation) is known as a model for reproducing the oxygen dissociation curve. SaO2 = (PaO2 / P50) n / [ 1 + (PaO2 / P50) n ] …(1) As illustrated in FIG. 2, P50 represents the value of PaO2 that gives 50% SaO2. 26.8 is known as a standard P50 value. If the oxygen dissociation curve shifts to the left, P50 decreases, and if the oxygen dissociation curve shifts to the right, P50 increases. In other words, if P50 as a constant can be identified, a calibrated oxygen dissociation curve that reflects the state of the subject 20 can be determined.

[0017] 1, a monitoring system 10 includes a processing device 11. An example of a technique for determining a calibrated oxygen dissociation curve using the processing device 11 will now be described.

[0018] The processing device 11 includes an input interface 111. The input interface 111 is configured as a hardware interface that receives first data D1 corresponding to actual measured values ​​of PaO2 and SaO2 of the subject 20. The actual measured values ​​of PaO2 and SaO2 are obtained by subjecting arterial blood collected from the subject 20 to analysis by a blood gas analyzer (not shown). The first data D1 may be transmitted from the blood gas analyzer or may be manually input by a user via a user interface (not shown).

[0019] The expression "data corresponding to an actual measured value" as used in this specification includes both cases where the data indicates the actual measured value itself, and cases where the data indicates a value obtained by applying a predetermined transformation to the actual measured value, an estimated value of the actual measured value, etc.

[0020] The first data D1 may be in the form of analog data or digital data depending on the specifications of the input source. When the first data D1 is in the form of analog data, the input interface 111 includes an appropriate conversion circuit including an A / D converter. This description is similarly applied to other data that can be accepted by the input interface 111, which will be described later.

[0021] The processing device 11 includes a processor 112. The processor 112 is configured to perform a calculation to specify P50 by substituting the measured values ​​of PaO2 and SaO2 corresponding to the first data D1 received by the input interface 111 into the formula (1). This calculation corresponds to the calibration of an oxygen dissociation curve in consideration of the "affinity of oxygen and hemoglobin" in the arterial blood of the subject 20 illustrated in FIG.

[0022] 1, the processing device 11 includes a storage 113. The processor 112 is configured to store data corresponding to the oxygen dissociation curve calibrated by the above calculation in the storage 113. The storage 113 can be realized by a semiconductor memory, a hard disk device, a magnetic tape device, or the like.

[0023] The above-mentioned measured value of SaO2 input as the first data D1 may be replaced with the measured value of SpO2. However, it is preferable to obtain the measured value of SaO2 because it is obtained together with PaO2 by a single collection of arterial blood and more directly represents the oxygen saturation of the arterial blood.

[0024] The input interface 111 of the processing device 11 is configured as a hardware interface capable of accepting second data D2 corresponding to at least one actual measured value of the PaCO2, arterial blood pH, body temperature, and 2,3-DPG concentration in the blood of the subject 20. The second data D2 may be accepted in addition to the first data D1 or instead of the first data D1.

[0025] The measured values ​​of PaCO2 and pH are obtained by subjecting arterial blood collected from the subject 20 to analysis by a blood gas analyzer (not shown). In this case, the second data D2 may be transmitted from the blood gas analyzer or may be manually input by a user via a user interface (not shown).

[0026] The body temperature may be acquired through a temperature sensor (not shown) attached to the subject 20. The second data D2 may be transmitted from the temperature sensor, or may be manually input by the user through a user interface (not shown). The body temperature does not necessarily have to be an actual measured value. 37° C., which is known as the standard temperature Ts of blood, may be used as the body temperature value.

[0027] The 2,3-DPG concentration is obtained by subjecting blood collected from the subject to measurement using, for example, an ultraviolet absorption measurement method using a measurement kit (not shown). In this case, the second data D2 may be transmitted from the blood gas analyzer, or may be manually input by the user via a user interface (not shown). The 2,3-DPG concentration does not necessarily have to be an actually measured value. The standard value Ds of the 2,3-DPG concentration, 4.65×10 -3 Molar may be used as a value for 2,3-DPG concentration.

[0028] Determining P50 in equation (1) based on the second data D2 can be done using the following equation: P50 = [ P50s ( P50c / P50s ) ( P50p / P50s ) ] (P50t / P50s ) ( P50d / P50s ) …(2) P50c = P50s + 1.273 x 10 -1 (Pc - Pcs) + 1.083 x 10 -4 ( PC - PCS ) 2 …(3) P50p = P50s - 25.535 (ph - phs) + 10.646 (ph - phs) 2 - 1.764 (ph - phs) 3 …(4) P50t = P50s + 1.435 (T - Ts) + 4.163 x 10 -2 (T - Ts) 2 + 6.86 x 10 -4 (T - Ts) 3 …(5) P50d = P50s + 795.63 ( D - Ds ) - 19660.89 ( D - Ds ) 2 …(6) Where: P50s: Standard value of P50 (26.8) Pc: Actual PaCO2 value Pcs: Standard value of PaCO2 (40 mmHg) ph: Measured pH value phs: standard pH value (7.24) T: Actual body temperature Ts: Standard value of blood temperature (37℃) D: Measured concentration of 2,3-DPG Ds: Standard value of 2,3-DPG concentration (4.65×10 -3 moles It is.

[0029] Note that the coefficient values ​​in the above formulas and the specific standard values ​​shown for some biological parameters are merely examples. For biological parameters that are not referenced, the standard values ​​of the biological parameters are substituted as the actual measured values ​​of each formula.

[0030] By identifying P50 as described above, the oxygen dissociation curve is calibrated in consideration of various biological parameters. The processor 112 stores data corresponding to the calibrated oxygen dissociation curve in the storage 113.

[0031] When both the first data D1 and the second data D2 are received by the input interface 111, the value of P50 used to calibrate the oxygen dissociation curve can be calculated by the following formula: P50 = k1 P50d1 + k2 P50d2 …(7) k1 + k2 = 1 …(8) where P50d1: P50 value determined using the first data D1 P50d2: P50 value determined using the second data D2 k1 and k2 are coefficients representing the contribution of each term to the finally determined P50, and can be appropriately determined by the user. k1 and k2 are positive real numbers.

[0032] Monitoring system 10 includes a pulse oximetry probe 12. Pulse oximetry probe 12 is attached to the body of a subject 20. Pulse oximetry probe 12 has a known configuration for measuring the SpO2 of subject 20.

[0033] Specifically, pulse oximetry probe 12 includes a plurality of light sources that emit light of a plurality of wavelengths that have different light absorption characteristics of oxygenated hemoglobin. For example, a first light having a central wavelength in the red range and a second light having a central wavelength in the infrared range are irradiated onto biological tissue including an artery of subject 20. Pulse oximetry probe 12 includes a light receiving element. The light receiving element is configured to detect the amount of each of the first light and the second light that has passed through the biological tissue and output a signal corresponding to the amount of light.

[0034] An attenuation A1 of the first light due to arterial blood is determined from the difference between the amount of the first light emitted from the light source and the amount of the first light detected by the light receiving element. Similarly, an attenuation A2 of the first light due to arterial blood is determined from the difference between the amount of the second light emitted from the light source and the amount of the second light detected by the light receiving element. If the ratio of the change in attenuation ΔA1 of the first light to the change in attenuation ΔA2 of the second light due to the pulsation of arterial blood is Φ, SpO2 can be given as a function of Φ by the following formula. SpO2 = f (Φ) …(9)

[0035] The input interface 111 of the processing device 11 is configured as a hardware interface capable of receiving third data D3 corresponding to an actual measurement value of SpO2 of the subject 20. A signal output from the pulse oximetry probe 12 is used for calculation processing of SpO2 by a pulse oximeter (not shown). The third data D3 may be transmitted from the pulse oximeter or may be manually input by a user through a user interface (not shown).

[0036] The processor 112 reads out data corresponding to the calibrated oxygen dissociation curve stored in the storage 113, and substitutes the actual measured value of SpO2 corresponding to the third data D3 in place of the value of SaO2 in the formula (1). This allows an estimated value of PaO2 based on the calibrated oxygen dissociation curve to be calculated.

[0037] The processing device 11 includes an output interface 114. The processor 112 is configured to output, from the output interface 114, data E1 corresponding to an estimate of PaO2.

[0038] The monitoring system 10 includes an output device 13. The output device 13 is configured to make the estimated PaO2 value notifiable to a user. The output device 13 may be realized by a display device, a printing device, a data transmission device, or the like. The processing device 11 may be a device independent of the output device 13, or may be a part of the output device 13.

[0039] The output interface 114 is configured as a hardware interface. The data E1 may be in the form of analog data or digital data, depending on the specifications of the output device 13. When the data E1 is in the form of analog data, the output interface 114 includes an appropriate conversion circuit including a D / A converter. This description is similarly applied to other data that can be output by the output interface 114, which will be described later.

[0040] According to the configuration of the present embodiment described above, the PaO2 value of the subject 20 is estimated using the actual measured value of SpO2 that can be obtained continuously and non-invasively, so that the subject 20's estimated value of PaO2 can be continuously monitored without imposing a burden associated with the invasiveness of blood sampling. In addition, the rule for converting the actual measured value of SpO2 into an estimated value of PaO2 is determined through a minimum number of blood gas analyses (including zero times) based on the values ​​of the biological parameters of the subject 20 that may affect the shift of the oxygen dissociation curve. Therefore, it is possible to obtain an estimated value of PaO2 that reflects the biological state of the subject 20 while further reducing the burden that may be imposed on the subject 20.

[0041] The input interface 111 of the processing device 11 may be configured as a hardware interface capable of receiving fourth data D4 corresponding to a value of the fractional inspired oxygen (FiO2) of the subject 20. The value of FiO2 may be an actual value, a set value, or an estimated value. The fourth data D4 may be transmitted from an oxygen inhalation device (not shown) connected to the subject 20, or may be manually input by a user through a user interface (not shown). FiO2 is an example of inspired oxygen information.

[0042] In this case, the processor 112 is configured to obtain a P / F ratio (PaO2 / FiO2) based on the estimated value of PaO2 obtained as described above and the actual value of FiO2 corresponding to the fourth data D4. The P / F ratio is an example of an index indicating the oxygenation ability of the subject 20.

[0043] The processor 112 is configured to output data E2 corresponding to the acquired P / F ratio from the output interface 114 to the output device 13. The output device 13 is configured to make the estimated value of the P / F ratio available for notification to a user.

[0044] Conventionally, the value of PaO2 obtained through blood gas analysis was used, so the calculated value of P / F ratio was inevitably time-discrete. However, with the above-mentioned configuration, the value of P / F ratio of subject 20 is estimated using the actual measured value of SpO2, which can be obtained continuously and non-invasively, so that continuous monitoring of oxygenation ability of subject 20 can be realized without imposing a burden associated with the invasiveness of blood sampling.

[0045] If based on PaO2, the index indicating the oxygenation ability of the subject 20 is not limited to the P / F ratio. Other examples of the index include A-aDO2, which corresponds to the difference between PAO2 (partial pressure of alveolar oxygen calculated from the alveolar gas formula) and PaO2, the ratio of A-aDO2 to PaO2 (A-aDO2 / PaO2), the ratio of PaO2 to PAO2 (PaO2 / PAO2), and the oxygenation index (OI). OI is obtained by multiplying the value of (FiO2 / PaO2) by the value of the mean airway pressure (MAP). Note that PAO2 can be an example of inhaled oxygen information.

[0046] Since SpO2 is generally presented as an integer value, the values ​​of PaO2 and P / F ratio estimated based on the actual measured value of SpO2 are also inevitably discrete. Therefore, the processor 112 of the processing device 11 can perform processing to artificially increase the resolution of the actual measured value of SpO2.

[0047] As an example, the processor 112 may be configured to perform a smoothing process on the third data D3 received by the input interface 111 at multiple time points. For example, a moving average process may be applied to multiple actual SpO2 measurements corresponding to a predetermined number of third data D3 acquired adjacently in time, thereby artificially increasing the resolution of the actual measurements. As a result, the resolution of the estimated values ​​of PaO2 and P / F ratio may also be increased.

[0048] As another example, the processor 112 may be configured to derive an approximation curve for the third data D3 received by the input interface 111 at multiple time points, and perform an extrapolation process or an interpolation process based on the approximation curve. In other words, the processor 112 may increase the resolution of the actual measurement value by estimating the value of SpO2 at a desired time point different from the multiple time points based on the derived approximation curve. As a result, the resolution of the estimated values ​​of PaO2 and P / F ratio may also be increased.

[0049] As another example, the input interface 111 may be configured to obtain an actual value of Φ in equation (9) as the third data D3. In this case, the processor 112 is configured to calculate an estimate of PaO2 based on the following equation: where g is a function different from f. PaO2 = g (Φ) …(10) Since the measured value of Φ corresponding to SpO2 has continuous values ​​before being rounded to integers by the function f, the resolution of the estimated values ​​of PaO2 and P / F ratio obtained by the above formula can also be improved.

[0050] As mentioned above, since SpO2 is generally presented as an integer value, the actual SpO2 value may be distributed within a certain range. For example, if the actual SpO2 presented is 95%, the actual SpO2 value may be distributed within a range of 94.5% to 95.4%. Therefore, the PaO2 value estimated from a specific actual SpO2 value may also be distributed within a certain range.

[0051] In view of this fact, the processor 112 of the processing device 11 may be configured to specify a possible range of the estimated value of PaO2 based on the actual measurement value of SpO2 corresponding to the third data D3. In this case, the processor 112 may be configured to output data E3 indicating the possible range of the specified estimated value of PaO2 from the output interface 114 to the output device 13.

[0052] According to such a configuration, it is possible to make it possible to notify the user through the output device 13 of the possible range of the estimated value of PaO2 of the subject 20.

[0053] At least one of the first data D1 and the second data D2 may be updated through periodic or irregular measurements. The processor 112 of the processing device 11 may be configured to correct the data corresponding to the calibrated oxygen dissociation curve stored in the storage 113 when the updated at least one of the first data D1 and the second data D2 is received by the input interface 111.

[0054] When the first data D1 is updated, the processor 112 re-specifies P50 by the method described with reference to formula (1) and corrects the oxygen dissociation curve with the re-specified P50 value. Data corresponding to the corrected oxygen dissociation curve is stored in the storage 113. Thereafter, estimation of PaO2 based on the actual measurement value of SpO2 corresponding to the third data D3 received by the input interface 111 is performed based on the rule corresponding to the corrected oxygen dissociation curve.

[0055] When the second data D2 is updated, the processor 112 re-specifies P50 by the method described with reference to equations (2) to (6) and corrects the oxygen dissociation curve with the re-specified P50 value. Data corresponding to the corrected oxygen dissociation curve is stored in the storage 113. Thereafter, estimation of PaO2 based on the actual measurement value of SpO2 corresponding to the third data D3 received by the input interface 111 is performed based on the rule corresponding to the corrected oxygen dissociation curve.

[0056] According to such a configuration, the latest biological condition of the subject 20 can be reflected in the estimated value of PaO2.

[0057] The first data D1 may include information indicating the time points at which the actual measured values ​​of PaO2 and SaO2 were obtained. Similarly, the second data D2 may include information indicating the time points at which the actual measured values ​​of PaCO2, arterial blood pH, body temperature, and blood 2,3-DPG concentration were obtained. The processor 112 of the processing device 11 may be configured to refer to the information and determine whether the time elapsed since each actual measured value was obtained exceeds a threshold value. The threshold value is appropriately determined based on a period during which it can be determined that the reliability of the first data D1 and the second data D2 is maintained.

[0058] In this case, when it is determined that the elapsed time exceeds the threshold, the processor 112 is configured not to estimate the PaO2 based on the third data D3 corresponding to the SpO2 acquired thereafter.

[0059] Since the first data D1 and the second data D2 are based on values ​​of biological parameters acquired discretely over time, the reliability of whether the data accurately reflects the biological state of the subject 20 decreases over time. Therefore, the reliability of the data corresponding to the calibrated oxygen dissociation curve stored in the storage 113 also decreases. With the above-described configuration, it is possible to prevent the PaO2 of the subject 20 from being estimated based on data with reduced reliability.

[0060] The processor 112 may be configured to output notification control data N from the output interface 114 to cause the output device 13 to notify the fact that the elapsed time exceeds the threshold. The notification may be made through at least one of a visual notification, an audible notification, and a tactile notification. The output device 13 in this case is an example of a notification device. The notification device may be a device independent of the output device 13.

[0061] According to this configuration, it is possible to prompt the user to update at least one of the first data D1 and the second data D2 in order to continue continuous monitoring of the PaO2 of the subject 20. The user may be allowed to select whether or not to calculate an estimated value of PaO2.

[0062] As illustrated in FIG. 1, the input interface 111 of the processing device 11 may be configured as a hardware interface capable of accepting fifth data D5 corresponding to a change in the vital sign of the subject 20.

[0063] The term "vital sign" as used herein means at least one of the values ​​of pulse, respiration, body temperature, blood pressure, and level of consciousness, or the change in the value over time. The change in the value over time may be visualized as a waveform or a graph. The expression "change in vital sign" as used herein refers to a change in vital sign over time that is medically significant.

[0064] The fifth data D5 may be transmitted from a device (not shown) that acquires the vital signs of the subject 20, or may be manually input by a user through a user interface (not shown).

[0065] In this case, the processor 112 is configured to temporally associate the fifth data D5 received by the input interface 111 with the estimated value of PaO2 calculated based on at least the third data D3. Note that the vital signs may be temporally associated with at least one of the first data D1, the second data D2, the third data D3, the fourth data D4, and the estimated value of the P / F ratio.

[0066] With this configuration, it is possible to identify an estimated PaO2 value at the time a change occurs in the vital signs of subject 20 from the estimated PaO2 values ​​of subject 20 obtained continuously over time, and to facilitate analysis of the correlation with the change in vital signs.

[0067] The processor 112 of the processing device 11 having the various functions described above may be realized by a general-purpose microprocessor that operates in cooperation with a general-purpose memory. Examples of the general-purpose microprocessor include a CPU, an MPU, and a GPU. Examples of the general-purpose memory include a ROM and a RAM. In this case, the ROM may store a computer program that executes the above-mentioned processing. The ROM is an example of a non-transient computer-readable medium in which a computer program is stored. The general-purpose microprocessor specifies at least a part of the program stored on the ROM, deploys it on the RAM, and executes the above-mentioned 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-transient computer-readable medium in which a computer program is stored.

[0068] The processor 112 may be realized by a dedicated integrated circuit capable of executing the above computer program, such as a microcontroller, an ASIC, or an FPGA. In this case, the above computer program is pre-installed in a storage element included in the dedicated integrated circuit. The storage element is an example of a computer-readable medium on which a computer program is stored. The processor 112 may also be realized by a combination of a general-purpose microprocessor and a dedicated integrated circuit.

[0069] Each of the configurations referred to in the above description is merely an example for facilitating understanding of the present disclosure. Each configuration example may be appropriately modified or combined with other configuration examples within the scope of the spirit of the present disclosure.

[0070] In the above embodiment, the processing device 11 is provided as a device independent of the pulse oximeter that measures the SpO2 of the subject 20. However, the processing device 11 may be built into the pulse oximeter.

[0071] The configurations listed below also form part of this disclosure. Item 1: an input interface for receiving at least one of first data corresponding to actual measured values ​​of arterial blood oxygen partial pressure and arterial blood oxygen saturation of the subject, and second data corresponding to at least one value of arterial blood carbon dioxide partial pressure, arterial blood pH, body temperature, and 2,3-DPG concentration in the blood of the subject; a processor for determining a rule for converting the subject's arterial blood oxygen saturation to an estimate of the subject's arterial blood oxygen partial pressure based on at least one of the first data and the second data; It is equipped with When the input interface receives third data corresponding to the percutaneous arterial oxygen saturation of the subject, the processor calculates the estimated value based on the third data and the rule. Processing unit. Item 2: When the input interface receives fourth data corresponding to the subject's inspired oxygen information, the processor obtains an index corresponding to the subject's oxygenation capability based on the estimated value and the fourth data. 2. The processing device according to item 1. Item 3: the input interface accepts the third data for a plurality of time points; The processor performs a smoothing process on the third data received for the plurality of time points to increase the resolution of the percutaneous arterial blood oxygen saturation. 3. The processing device according to item 1 or 2. Item 4: the input interface accepts the third data for a plurality of time points; The processor derives an approximation curve of the third data received for the plurality of time points, and estimates a value of the percutaneous arterial blood oxygen saturation at a time point different from the plurality of time points based on the approximation curve, thereby improving the resolution of the percutaneous arterial blood oxygen saturation. 3. The processing device according to item 1 or 2. Item 5: A first light and a second light having different wavelengths are irradiated onto the biological tissue of the subject, the third data corresponds to an actual measurement value of a ratio of a change in attenuation of the first light and a change in attenuation of the second light each passing through the biological tissue; 9. The processing device according to any one of items 1 to 8. Item 6: The processor identifies a possible range of the estimated value based on the percutaneous arterial blood oxygen saturation corresponding to the third data. 6. The processing device according to any one of items 1 to 5. Item 7: When at least one of the first data and the second data is updated, the processor corrects the rule based on at least one of the updated first data and the updated second data. 7. The processing device according to any one of items 1 to 6. Item 8: the processor does not calculate the estimated value based on the third data when the elapsed time since the actual measurement value was acquired exceeds a threshold value. 8. The processing device according to any one of items 1 to 7. Item 9: the processor causes a notification device to notify that the elapsed time exceeds the threshold. 9. The processing device according to any one of items 1 to 8. Item 10: and when the input interface receives fifth data corresponding to a change in the subject's vital sign, the processor temporally associates the fifth data with at least the estimate. 10. The processing device according to any one of items 1 to 9. [Explanation of symbols]

[0072] 11: Processing device, 111: Input interface, 112: Processor, 13: Output device, D1: First data, D2: Second data, D3: Third data, D4: Fourth data, D5: Fifth data

Claims

1. an input interface for receiving at least one of first data corresponding to actual measured values ​​of arterial blood oxygen partial pressure and arterial blood oxygen saturation of the subject, and second data corresponding to at least one value of arterial blood carbon dioxide partial pressure, arterial blood pH, body temperature, and 2,3-DPG concentration in the blood of the subject; a processor for determining a rule for converting the subject's arterial blood oxygen saturation to an estimate of the subject's arterial blood oxygen partial pressure based on at least one of the first data and the second data; It is equipped with When the input interface receives third data corresponding to the subject's percutaneous arterial oxygen saturation, the processor calculates the estimated value based on the third data and the rule. Processing unit.

2. When the input interface receives fourth data corresponding to the subject's inspired oxygen information, the processor obtains an index corresponding to the subject's oxygenation capability based on the estimated value and the fourth data. The processing device of claim 1 .

3. the input interface accepts the third data for a plurality of time points; The processor performs a smoothing process on the third data received for the plurality of time points to increase the resolution of the percutaneous arterial blood oxygen saturation. The processing device of claim 1 .

4. the input interface accepts the third data for a plurality of time points; the processor derives an approximation curve of the third data received for the plurality of time points, and estimates a value of the percutaneous arterial blood oxygen saturation at a time point different from the plurality of time points based on the approximation curve, thereby improving the resolution of the percutaneous arterial blood oxygen saturation. The processing device of claim 1 .

5. A first light and a second light having different wavelengths are irradiated onto the biological tissue of the subject, the third data corresponds to an actual measurement value of a ratio of a change in attenuation of the first light and a change in attenuation of the second light each passing through the biological tissue; The processing device of claim 1 .

6. The processor identifies a possible range of the estimated value based on the percutaneous arterial blood oxygen saturation corresponding to the third data. The processing device of claim 1 .

7. When at least one of the first data and the second data is updated, the processor corrects the rule based on at least one of the updated first data and the updated second data. The processing device of claim 1 .

8. the processor does not calculate the estimated value based on the third data when the elapsed time since the actual measurement value was acquired exceeds a threshold value. The processing device of claim 1 .

9. When the elapsed time since the actual measurement value was acquired exceeds a threshold, the processor causes a notification device to notify that the elapsed time exceeds the threshold. The processing device of claim 1 .

10. and when the input interface receives fifth data corresponding to a change in the subject's vital sign, the processor temporally associates the fifth data with at least the estimate. The processing device of claim 1 .

11. A computer program executable by a processor installed in a processing device, When executed, the processing device: receiving at least one of first data corresponding to actual measured values ​​of arterial blood oxygen partial pressure and arterial blood oxygen saturation of the subject, and second data corresponding to at least one value of arterial blood carbon dioxide partial pressure, arterial blood pH, body temperature, and 2,3-DPG concentration in the blood of the subject; determining a rule for converting the subject's arterial blood oxygen saturation to an estimate of the subject's arterial blood oxygen partial pressure based on at least one of the first data and the second data; Accepting third data corresponding to a percutaneous arterial oxygen saturation level of the subject; calculating the estimated value based on the third data and the rule; Computer program.

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