Respiratory function test simulator

Abstract

To provide a device or the like that enables the acquisition of a technique of precise examination at low costs.SOLUTION: In a flow sensor type spirometer not having a gas supply function and a gas concentration detection function, when a subject is being subjected to resting ventilation, a simulation of repeating calculation of He concentration according to actual exhalation and inhalation is executed, and thereby, the He concentration displayed in a display together with a spirogram gradually decreases and finally a stable equilibrium state is achieved.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a respiratory function test simulator that simulates a respiratory function test. [Background technology]

[0002] Conventionally, there are spirometers capable of measuring vital capacity (VC), forced vital capacity (FVC), etc. (see, for example, Patent Document 1, Patent Document 2, and Non-Patent Document 1). Among them, there are precision testing devices capable of supplying a test gas (e.g., helium (He)) to a subject and performing precision tests such as functional residual capacity (FRC) (see, for example, Patent Document 2 and Non-Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-153886 [Patent Document 2] Japanese Patent Application Publication No. 2017-086704 [Non-patent literature]

[0004] [Non-Patent Document 1] Respiratory Function Test Handbook (Japanese Respiratory Society, Pulmonary Physiology Specialist Committee), Medical Review Publishing Summary of the Invention [Problem to be solved by the invention]

[0005] Spirometer testing can only produce reliable test results if the subject inhales and exhales at the appropriate timing and with the appropriate intensity according to a predetermined testing procedure. Therefore, it is extremely important that the testing procedure and the subject's breathing are appropriate in clinical settings, and these are also included in the scope of questions in the National Medical Laboratory Technologist Examination. Testers must master the required testing procedures for each test item and how to instruct the subject to breathe according to those procedures. Given this reality, it is considered preferable for testers to acquire skills not only through classroom learning but also by actually using a spirometer on a subject.

[0006] However, precision testing devices are expensive compared to airflow-type spirometers that use pressure sensors (see, for example, Patent Document 1 and Non-Patent Document 1), and because the number of devices installed in medical institutions is relatively small, it is difficult to acquire skills using the actual device. Furthermore, it is extremely difficult to introduce precision testing devices into educational institutions, and opportunities for students to experience precision testing are extremely limited. Even if precision testing devices were available, there would be a cost problem due to the use of testing gases to acquire precision testing skills.

[0007] The present invention has been made in consideration of the above-mentioned problems, and its object is to enable the acquisition of precision testing techniques at low cost. [Means for solving the problem]

[0008] The above-mentioned problems are solved by the following means. Note that, although the reference numerals used in the description and drawings of the embodiments of the invention to be described later are added in parentheses for reference, the components of the present invention are not limited to these. Various changes and modifications can be made within the scope of the present invention.

[0009] The first means is a respiratory function test simulator (1) that performs a simulation of a detailed examination related to gas concentration (FRC test, CV test, DLCO test), and is characterized by comprising a measurement unit (flow sensor 10, CPU 53) that measures respiratory flow or respiratory capacity (spirogram and spirometry based on the spirogram, etc.), an output unit (display 56, speaker 58) that outputs guidance information corresponding to the detailed examination (type of gas used in the detailed examination, breathing method that the subject should perform), and a generation unit (CPU 53) that generates simulation data related to the detailed examination based on the data measured by the measurement unit.

[0010] The second means is characterized in that in the first means, the guidance information includes information on the gases used in the detailed examination (He in the case of an FRC examination, O2 in the case of a CV examination, and a four-type mixed gas in the case of a DLCO examination) and information on breathing instructions to be given to the subject in the detailed examination (resting ventilation in the case of an FRC examination, exhalation up to the maximum expiratory position and maintaining the expiratory flow rate within a predetermined range in the case of a CV examination, inhalation up to the maximum inhalation position and breath holding at the maximum inhalation position and exhalation in one breath in the case of a DLCO examination).

[0011] The third means is characterized in that, in the first means, the generation unit generates a gas concentration curve based on data measured by the measurement unit (actual measurement data) and a predetermined value corresponding to the detailed examination (a reference value calculated by a reference value prediction formula based on the subject's data).

[0012] The fourth means is characterized in that, in the third means, the generation unit is capable of generating a first gas concentration curve based on data (actual measurement data) measured by the measurement unit and a first predetermined value calculated based on a prediction formula corresponding to a detailed examination (a reference value calculated by a reference value prediction formula based on data of the subject), and generates a second gas concentration curve having a degree of suitability different from that of the first gas concentration curve based on the data (actual measurement data) measured by the measurement unit and a second predetermined value corresponding to the detailed examination that is different from the first predetermined value (for example, a set value obtained by multiplying the reference value by a predetermined coefficient).

[0013] The fifth means is any one of the first to fourth means, characterized in that the detailed examination is a functional residual capacity test (FRC), the guidance information includes information notifying the use of He and information instructing quiet ventilation, and the generation unit generates a gas concentration curve showing the He concentration.

[0014] The sixth means is characterized in that, in any one of the first to fourth means, the detailed examination is a closing volume test (CV), the guidance information includes information notifying the use of O2, information instructing exhalation up to the maximum expiratory level, and information instructing maintenance of the expiratory flow rate within a predetermined range, and the generation unit generates a gas concentration curve indicating the N2 concentration.

[0015] The seventh means is any one of the first to fourth means, wherein the detailed examination is a pulmonary function diffusion test (DLCO), and the guidance information is CO, He, O 2、 The device includes information notifying the use of a four-component mixed gas including N2, information instructing the patient to inhale up to the maximum inhalation position, information instructing the patient to hold their breath for a predetermined period at the maximum inhalation position, and information instructing the patient to exhale in one breath, and the generating unit generates a gas concentration curve showing the CO concentration.

[0016] The eighth means is a program executed by a respiratory function test simulator (1) that executes a simulation of a detailed examination (FRC test, CV test, DLCO test) related to gas concentration, and is characterized by measuring respiratory flow or respiratory capacity (spirogram and spirometry based on the spirogram, etc.) using a measurement unit (flow sensor 10, CPU 53), outputting guidance information corresponding to the detailed examination (type of gas used in the detailed examination, breathing method that the subject should perform) using an output unit (display 56, speaker 58), and generating simulation data related to the detailed examination by a generation unit (CPU 53) based on the data measured by the measurement unit. [Effects of the Invention]

[0017] According to the present invention, it is possible to acquire the skills of precision testing at low cost. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 is a diagram illustrating an example of a respiratory function test simulator according to the present embodiment. [Figure 2] FIG. 1 is a diagram showing a comparison example between spirometry and detailed examination items. [Figure 3] FIG. 10 is a diagram showing an example of a He concentration curve in an FRC inspection. [Figure 4] 10 is a flowchart showing an example of a simulation procedure for an FRC inspection. [Figure 5] FIG. 10 is a diagram showing an example of calculation of He concentration. [Figure 6] FIG. 10 is a diagram showing an example of a simulation result of an FRC inspection. [Figure 7] FIG. 10 is a diagram showing an example of an N2 concentration curve in a CV test. [Figure 8] 10 is a flowchart showing an example of a simulation procedure for a CV inspection. [Figure 9] FIG. 10 is a diagram showing an example of a waveform of dummy data. [Figure 10] FIG. 10 is a diagram showing an example of a volume curve in a DLCO test. [Figure 11] 10 is a flowchart illustrating an example of a simulation procedure for a DLCO inspection. [Figure 12] FIG. 1 is a diagram showing an example of a CO concentration curve in a DLCO test. [Figure 13] FIG. 10 is a diagram showing an example of the results of a questionnaire regarding detailed examinations. [Figure 14] FIG. 10 is a diagram showing an example of a method for generating an N2 concentration curve. [Figure 15] FIG. 10 is a diagram showing an example of a method for generating an N2 concentration curve. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings.

[0020] [Respiratory function test simulator measurement function] 1 is an explanatory diagram showing a respiratory function test simulator 1 according to this embodiment. In this embodiment, a flow sensor-type spirometer is used as the respiratory function test simulator 1. Therefore, although it does not have the function of supplying test gas to the subject (nor a sensor for measuring gas concentration), it is at least capable of measuring a spirogram (time-airflow curve), and can obtain VC, FVC, forced expiratory volume in 1 second (FEV1), and fractional expiratory volume in 1 second (FEV1 / FVC).

[0021] The respiratory function test simulator 1 is equipped with a respiratory function test flow sensor (hereinafter referred to as "flow sensor") 10. The flow sensor 10 is a flow rate detection unit that is attached to the mouth of a subject to measure the inhalation flow rate and exhalation flow rate of the subject. The information (signal) detected by the flow sensor 10 is a pressure difference signal (a differential pressure signal before and after a resistor 14) that has a one-to-one relationship (linear relationship) with the flow rate. This differential pressure signal is taken in by the main body 50 and converted into a corresponding flow rate signal based on this differential pressure signal.

[0022] The flow sensor 10 is configured to include a resistor 14 that generates a pressure drop for inhalation and exhalation, a first pressure detection port 5a that detects the pressure (static pressure) on the subject side of the resistor 14, and a second pressure detection port 5b that detects the pressure (static pressure) on the opposite side of the resistor 14 from the subject. The resistor 14 generates a pressure difference (differential pressure) between before and after the resistor 14 when the exhalation and inhalation pass through the resistor 14.

[0023] The main body 50 is equipped with a first pressure transmission tube 51a that transmits the pressure detected at the first pressure detection port 5a to the differential pressure sensor 51, a second pressure transmission tube 51b that transmits the pressure detected at the second pressure detection port 5b to the differential pressure sensor 51, the differential pressure sensor 51 that converts the differential pressure before and after the resistor 14 into a corresponding electrical signal, an A / D converter 52 that converts the electrical signal (analog signal) output by the differential pressure sensor 51 into a predetermined digital signal, a CPU 53 that executes a measurement program and calculates the exhalation and inhalation flow rates, etc. based on the converted digital signal, a RAM 54 that temporarily stores a digital signal related to the output signal of the differential pressure sensor 51 output by the A / D converter 52, a ROM 55 that stores the measurement program, measurement data, etc., including a calibration formula (relational formula) between the flow rate and the output voltage of the differential pressure sensor 51, a display 56 that displays operation icons and measurement data, etc., a D / A converter 57 that generates an analog voltage corresponding to the digital signal from the CPU 53, and a speaker 58 that outputs operation guidance, etc. by voice.

[0024] The measurement data such as flow rate and volume stored in the ROM 55 is transmitted to a controller 56a of the display 56. The controller 56a drives an LCD driver 56b based on a control signal from the CPU 53 to display measurement data such as spirograms on the display 56. The display 56 is equipped with multiple touch sensors (not shown), and the examiner operates them to start and end a measurement program, input (including selection) measurement parameters, and so on.

[0025] [Simulation function of the respiratory function test simulator] The respiratory function test simulator 1 of this embodiment is capable of measuring a spirogram as described above, and is also capable of simulating tests that are normally performed using precision testing devices (Patent Document 2, Non-Patent Document 1). A simulation program for the precision test is stored in the ROM 55, and is executed by the CPU 53 based on the operation of the examiner.

[0026] FIG. 2 is a diagram illustrating the difference between spirometry, a test item obtainable from a spirogram, and a test item in a detailed examination performed by supplying gas to a subject. Spirometry can be measured, for example, using a flow sensor-type spirometer (see Patent Document 1), and is intended for screening for obstructive respiratory disorders and restrictive respiratory disorders. Spirometry includes VC, FVC, forced expiratory volume in one second, and forced expiratory volume in one second, as well as a flow-volume curve. Because the gas inhaled by the subject is room air, the device can be made small and lightweight, and each test item is measured based on the airflow detected by the flow sensor.

[0027] On the other hand, detailed examination items can be measured using a volumetric spirometer (also called a rolling seal spirometer), which allows the subject to inhale test gas supplied into a cylinder by moving a bell inside the cylinder in response to the subject's breathing, as shown in Patent Document 2 and Non-Patent Document 1. The purpose of these examinations is to evaluate lung volume fractions, ventilation maldistribution, and gas exchange disorders. Spirometry can also be measured using a volumetric spirometer. Detailed examination items include functional residual capacity (FRC), closing volume (CV), and pulmonary diffusion capacity (DLCO). FRC is performed by having the subject inhale a He-mixed gas, and the He concentration is measured using a He sensor. CV is performed by having the subject inhale 100% O2, and the N2 concentration corresponding to the residual volume is measured using an N2 sensor. DLCO is performed by having the subject inhale a four-gas mixture (He, CO, O2, and N2), and the He concentration is measured using a He sensor, and the CO concentration is measured using a CO sensor.

[0028] As shown in Figure 2, the detailed examination items cannot be measured using a flow sensor type spirometer. Therefore, technical skills should normally be acquired using a volumetric spirometer. However, in this embodiment, as described below, the flow sensor type spirometer is equipped with a function for simulating detailed examinations, making it possible to acquire detailed examination skills without using a volumetric spirometer.

[0029] In this embodiment, in regard to the simulation of a detailed examination, instead of simply displaying preset pseudo data, simulation data is generated based on actual spirograms acquired from subjects, making it possible to present simulation data that closely resembles the behavior of actual data from subjects in clinical settings, thereby enabling efficient learning of examination techniques.

[0030] The following formula shows an example of a method for calculating the gas concentration in this embodiment. Y=aX+b...(Equation 1)

[0031] Y is the measured value, X is the gas concentration, a is the coefficient, and b is the intercept. When a relational equation between the measured value and the gas concentration is thus defined, the gas concentration can be back-calculated by using a predicted value (which may be called a reference value) obtained by a reference value prediction equation based on the subject's actual data (age, sex, height, etc.) as the measured value. Based on the back-calculated gas concentration and the actually measured spirogram, a change curve of the gas concentration can be generated and displayed. In the example of (Equation 1), the relationship between the measured value and the gas concentration is defined as a linear function, but it is not limited to this and may be defined as another function such as a quadratic function or a logarithmic function.

[0032] (FRC inspection simulation) The principle of the FRC test is to connect the lungs to a circuit of known volume containing a known concentration of an indicator gas, instruct the subject to breathe repeatedly, and by thoroughly mixing the gases in both spaces, the FRC can be calculated from the change in the concentration of the indicator gas. Helium (He), which is not absorbed by the lungs, is often used as the indicator gas. As the subject rebreathes at a resting expiratory position until the He concentration reaches equilibrium, the He concentration curve gradually decreases from its peak with each resting ventilation, converging to the equilibrium concentration, as shown in Figure 3. This He concentration curve is reproduced in the FRC test simulation.

[0033] FIG. 4 is a flowchart corresponding to the FRC inspection simulation. When the inspector selects an object displayed on the display 56 that will execute the FRC inspection simulation, the CPU 53 executes the simulation program and the FRC inspection simulation is performed. A message prompting the inspector to prepare an O2·He mixed gas, which is the FRC inspection gas, is displayed on the display 56 (S110). In addition, a "Start Preparation" button is displayed to fill the cylinder with the inspection gas and prepare for FRC measurement (S120). From this information, the inspector can understand the type of inspection gas to be used in FRC measurement.

[0034] When the examiner operates the "Start preparation" button, the messages "Breathing circuit ventilation in progress" and "Gas injection in progress" are displayed on the display 56 (S130). As described above, the respiratory function test simulator 1 is a flow sensor type spirometer and does not have a gas supply function, so these displays are pseudo-displays, but the examiner can understand the process of the test gas being filled into the cylinder prior to the start of measurement. Note that a simulated sound of the test gas being filled into the cylinder may be output from the speaker 58 to more closely resemble a real test environment.

[0035] When the examiner operates the "Start Measurement" button displayed on the display 56 after the messages "Respiratory circuit ventilation in progress" and "Gas injection in progress" have finished being displayed (after gas injection has been completed) (S140), the flow sensor 10 provided in the respiratory function test simulator 1 measures the actual spirogram of the subject and displays it on the display 56 (S150). Furthermore, the display 56 displays the message "Please perform quiet ventilation" (S160). This allows the examiner to understand the process of having the subject inhale the test gas through quiet ventilation during the FRC test.

[0036] Next, as described above, the CPU 53 calculates the predicted FRC value (which may also be called the FRC reference value) using a reference value prediction formula based on the actual data of the subject (age, sex, height, weight, etc.). This reference value prediction formula may be the formula disclosed in Non-Patent Document 1. Note that the reference value prediction formula (reference value prediction formulas for FRC, and CV and DLCO, which will be described later) is not limited to the formula disclosed in Non-Patent Document 1, and other prediction formulas may also be used. Furthermore, the actual data of the subject required for the reference value prediction formula may include not only age, sex, height, and weight, but also other data such as body surface area (BSA).

[0037] The following equation shows the relationship between the He concentration, the circuit capacitance, and the FRC. C1 (He concentration in the circuit before measurement) × (circuit capacity) = C2 (He concentration after equilibrium) × (circuit capacity + FRC) ... (Equation 2)

[0038] In this embodiment, the He concentration is calculated using the He concentration in the circuit before measurement begins as 11% and the calculated predicted FRC value as the FRC in (Equation 2). In the example of FIG. 5(a), the circuit volume before measurement begins (before He inhalation) is shown as the FRC dead space volume, which is 10.50 L. The amount of He in the circuit before measurement begins is 11% × 10.50 L = 1.155 L. Meanwhile, the subject's FRC calculated based on the prediction formula is 3.38 L. Because the subject has not inhaled He before measurement begins, the He concentration in the lungs is 0%, and the amount of He in the lungs is 0.0 L. In this case, the sum of the amount of He in the circuit and the amount of He in the lungs is 1.155 L.

[0039] As shown in Figure 5(b), when the subject inhales, the TV (TVI, which is the inhaled volume of the tidal volume in this case) is subtracted from the FRC dead space volume, and the TV (TVI in this case) is added to the FRC. In this example, 0.50 L is inhaled, resulting in 0.50 L x 0.11% = 0.055 L being taken into the lungs, the He concentration changing from 0% to 1.42%, and the amount of He in the circuit becoming 10.00 L x 11% = 1.10 L.

[0040] Next, as shown in Figure 5(c), when the subject exhales, the amount equivalent to the TV (in this case, TVE, which is equivalent to the exhaled volume of the tidal volume) is subtracted from the FRC + TV, and the amount equivalent to the TV (in this case, TVE) is added to the FRC dead space volume after the subtraction. In this example, 0.50 L is exhaled, and 0.50 L x 1.42% = 0.0071 L of He is returned to the circuit, making the amount of He in the circuit 1.1071 L, or 10.54%.

[0041] As shown in Figure 6, the gas concentration calculations shown in Figures 5(b) and 5(c) are repeated in accordance with the subject's actual inhalation and exhalation, causing the He concentration displayed on display 56 to gradually decrease and eventually reach a stable equilibrium state (where the rate of decrease in He concentration falls within a predetermined range). In this example, as shown in Figure 5(d), the He concentration stabilizes when the He concentration in the circuit and lungs reaches 8.33%, and the total amount of He in the circuit and lungs remains at 1.155 L. In this way, the examiner can understand how the He concentration changes as the subject repeats quiet ventilation in the simulated FRC test (see Figure 6).

[0042] 4, when the He concentration recalculated in accordance with the subject's quiet ventilation is stable (YES in S190), the CPU 53 notifies the user that the FRC test is finished by displaying "He concentration is stable" on the display 56 (S191). Then, the CPU 53 displays the test results (for example, the calculated predicted FRC value and other test results obtainable in the FRC test) on the display 56 (S200), and the simulation of the FRC test is finished.

[0043] On the other hand, as will be described later, if the He concentration does not stabilize even after waiting for a predetermined period of time (NO in S190) due to the setting of an FRC value (an unfavorable setting) that differs from the value predicted by the reference value prediction formula (reference value), the CPU 53 displays an "End Measurement" button on the display 56 to end the FRC test (S192). Based on the examiner's operation of the "End Measurement" button, the test result (which may be the set FRC value or the result that the FRC could not be measured appropriately) is displayed on the display 56 (S200), and the simulation of the FRC test is ended.

[0044] If a detailed examination item cannot be measured properly, such as when the measurement ends before the He concentration stabilizes in the simulation of an FRC examination, guidance that the item could not be measured properly may be provided via the display 56 or speaker 58, and further guidance may be provided to enter this information as a comment in the electronic medical record, etc. (rather than leaving it unrecorded). This allows the examiner to understand what to do if the measurement ends with an irregular result.

[0045] In the example of Figure 6, the He concentration smoothly decreases and reaches an equilibrium state, and the TV shown by the spirogram is stable at a constant amplitude. In this embodiment, by using a predicted value as the FRC, it is possible to reproduce the state in which the He concentration smoothly decreases and stabilizes through repeated quiet ventilation.

[0046] On the other hand, if the obstruction is severe, the He concentration will decrease to a certain extent, but it may take a long time for it to stabilize from there. In this embodiment, as described above, the predicted FRC value is used, but by setting an FRC value different from the predicted FRC value (for example, an FRC set value obtained by multiplying the predicted FRC value by 1.2 as a coefficient), the He concentration in the case of severe obstruction can be reproduced. In this way, the examiner can experience both good and bad cases in FRC inspection.

[0047] (CV test simulation) CV testing is a pulmonary function test that detects maldistribution of inspired air by washing out an indicator gas from the lungs. The indicator gas is typically nitrogen (N2). Figure 7 shows the details of the N2 concentration curve in a CV test. The N2 concentration curve in a CV test is a single-expiration curve divided into phases 1 through 4. Phase 1 represents dead space air containing 100% O2 only, phase 2 represents a mixture of dead space air and alveolar air, phase 3 represents alveolar air, and phase 4 represents CV. Phase 3 exhibits a flat curve and is called the alveolar plateau. Pulsatile waves consistent with cardiac beats are observed during this phase. When alveolar air from various locations contributes to exhalation at a constant rate, the alveolar plateau is formed. In phase 4, the N2 concentration rises sharply toward the maximum expiratory level. The lung volume (expiratory volume) during phase 4 is the CV.

[0048] FIG. 8 is a flowchart corresponding to the simulation of a CV test. When the examiner selects an object displayed on the display 56 that will execute the CV test simulation, the CPU 53 executes the simulation program and the CV test simulation is performed. A message prompting the examiner to prepare O2, which is the inhalation gas, is displayed on the display 56 (S210). Also, a "Start Preparation" button is displayed (S220) to fill the inhalation gas into a cylinder and prepare for CV measurement. From this information, the examiner can understand the type of gas used in CV measurement.

[0049] When the examiner operates the "Start preparation" button, the messages "Respiratory circuit ventilation in progress" and "Gas injection in progress" are displayed on the display 56 (S230). After the messages "Respiratory circuit ventilation in progress" and "Gas injection in progress" have finished being displayed (after gas injection has been completed), the examiner operates the "Start measurement" button displayed on the display 56 (S240), and the actual spirogram of the subject is measured by the flow sensor 10 provided in the respiratory function test simulator 1 and displayed on the display 56 (S250). Furthermore, the message "Please perform quiet ventilation" is displayed on the display 56 (S260).

[0050] Next, as described above, the CPU 53 calculates a predicted CV value (which may also be called a CV reference value) using a reference value prediction formula based on the actual data of the subject (age, sex, etc.). This reference value prediction formula may be the formula disclosed in Non-Patent Document 1. Next, the CPU 53 performs a calculation to stretch or contract the dummy data of the N2 concentration curve prepared in advance, shown in Fig. 9, in the direction of the expiratory volume, corresponding to the actual VC value (for example, the value of a VC test performed prior to the CV test simulation) or the predicted VC value calculated using the reference value prediction formula based on the subject's data.

[0051] Here, for the fourth phase, a calculation is performed to expand or contract the data in the direction of the expiratory volume according to the predicted CV value, and this expansion or contraction is absorbed by expanding or contracting the third phase. Note that if the expiratory volume assumed in the dummy data matches the measured VC or predicted VC value, there is no need to expand or contract the dummy data. Also, if the CV assumed in the dummy data matches the predicted CV value, there is no need to expand or contract the fourth phase.

[0052] Alternatively, standard dummy data may be prepared (stored in ROM 55) for each subject's data (age, sex, height, etc.), and dummy data corresponding to the actual subject's data (age, sex, height, etc.) may be selected and stretched. In this way, the dummy data stretched or stretched as necessary is provisionally set as the N2 concentration curve (S270). Alternatively, multiple dummy data corresponding to VC (e.g., four values ​​of VC=2.5L, 3.5L, 4.5L, 5.5L) may be prepared, and dummy data close to the actual subject's VC may be selected and stretched.

[0053] Alternatively, one may be selected from a plurality of base waveforms (e.g., five waveforms: CV1, CV2, CV3, CV4, and CV5), and the selected base waveform may be stretched or contracted in the direction of the expiratory volume according to the actually measured expiratory volume. For example, one may be selected from the plurality of base waveforms for each measurement in a predetermined order (e.g., the order CV1 → CV2 → CV3 → CV4 → CV5), or one may be selected based on a random number.

[0054] Then, a message urging the subject to exhale up to the maximum expiratory level, "Please exhale slowly until you can no longer exhale," is displayed on the display 56 (S280). Next, a message urging the subject to inhale up to the maximum inhalation level, "Please inhale slowly until you can no longer exhale," is displayed on the display 56 (S290). This message is intended to encourage the subject to inhale oxygen.

[0055] Next, the CPU 53 displays on the display 56 a message urging the user to exhale up to the maximum expiratory level, saying, "Exhale slowly until you can no longer exhale" (S300).Then, the CPU 53 displays on the display 56 the flow actually measured by the flow sensor, and also displays on the display 56 a message instructing the user to maintain the expiratory rate within a predetermined range, saying, "Maintain the expiratory rate within the range of 0.3 to 0.5 L / s" (S310).

[0056] The CPU 53 also generates an N2 concentration curve in response to an increase in the exhaled air volume based on the spirogram actually measured in the CV test simulation (S320). The N2 concentration curve is generated by tracing a provisionally set, non-displayed N2 concentration curve in accordance with the exhaled air volume being measured (displaying the N2 concentration at a point corresponding to the exhaled air volume). This makes it appear as if the N2 concentration is changing in real time. For example, with regard to the third phase, when the exhaled air flow (flow measured by the flow sensor) being measured falls below a predetermined value (e.g., less than 0.2 L / s), the third phase may be terminated (the provisionally set third phase portion of the dummy data may be expanded or contracted) and the fourth phase may be started (the provisionally set fourth phase portion of the dummy data may be expanded or contracted and its tracing may be started).

[0057] Then, based on detecting inspiration after completion of exhalation up to the maximum expiratory level (S330), the CPU 53 terminates the generation of the N2 concentration curve, displays the test results (e.g., the calculated CV predicted value and other test results obtainable in the CV test) on the display 56 (S340), and terminates the simulation of the CV test.

[0058] In this embodiment, as described above, the predicted CV value is used to provisionally set the N2 concentration curve, but by setting a CV value different from the predicted CV value (for example, a set CV value obtained by multiplying the predicted CV value by 1.2 as a coefficient), the CV of the fourth phase can be increased, and the N2 concentration when the obstruction is severe can be reproduced. In this way, the examiner can experience both good and bad cases in the CV test.

[0059] (DLCO inspection simulation) Fig. 10 is an explanatory diagram showing the details of the volume curve in the DLCO test. In the DLCO test, CO, He, O 2、A four-component gas mixture containing N2 (e.g., 0.3%, 10%, 21%, or 68.7%) is inhaled from maximum expiration (RV level) in one go, and after 10 seconds of breath-holding, the first 750 mL, which is affected by dead space, is discarded, and 0.5 to 1 L of alveolar air is collected and analyzed. The CO2 concentration in exhaled alveolar air (FACO) relative to the CO2 concentration in inhaled air (FICO) and the He concentration in exhaled alveolar air (FAHe) relative to the He concentration in inhaled air (FIHe) are measured and compared.

[0060] In this embodiment, the He concentration curve and the CO concentration curve are generated by the following methods, the outline of which is shown in (1) to (9). (1) DLCO is a predicted value (reference value). (2) VI (inspiratory vital volume during DLCO measurement) uses actual measurement data obtained during measurement. VI in DLCO testing can be said to be the volume of inhaled air when a four-component gas mixture is inhaled in one go from the maximum expiratory position (RV level). (3) VA (alveolar volume under standard conditions (STPD)) is calculated from VI and RV (residual volume). (4) RV (residual volume) is a predicted value (reference value). (5) FIHe (He concentration in inhaled air) is the initial He concentration setting. (6) FICO (CO concentration in inhaled air) is the initial CO concentration setting. (7) FAHe (He concentration in exhaled alveolar air) is calculated by back-calculating from VA using the VA' formula. (8) FACO (CO concentration in exhaled alveolar air) is calculated by back-calculating from the DLCO formula. Then, (9) the gas distribution concentration is changed based on the following (Equation 3-1) and (Equation 3-2) so as to converge to the FAHe and FACO calculated by back calculation, and the result is displayed. The concentration curve is obtained by multiplying the difference concentration between FI and FA by (1-EXP (-elapsed time / time constant)) and subtracting it from FI. That is, Current He gas concentration = FIHe - (FIHe - FAHe) x (1 - EXP (- elapsed time ÷ He time constant))...(Equation 3-1) Current CO gas concentration = FICO - (FICO - FACO) x (1 - EXP (- elapsed time ÷ CO time constant))...(Equation 3-2) It is expressed as:

[0061] The DLCO calculation formula is shown below. DLCO=[VA×1000×60 / ((PB-47)×BHT)]×ln(FACO(0) / FACO) …(Formula 4) Here, BHT is the breath-hold time, which is a fixed value (10.0 seconds). Note that BHT is not limited to 10.0 seconds and may be any other time. PB is atmospheric pressure (a fixed value (760 Torr) or a manually set value). The value 47 to be subtracted is the saturated water vapor partial pressure at 37°C. FACO(0) is the alveolar CO concentration immediately after CO inhalation. where: FACO(0)=(FAHe / FIHe)×FICO…(Formula 4-1) VA(BTPS)=(VI+RV)…(Formula 4-2) VA'(BTPS)=(VI×(FIHe / FAHe)-VD) …(Formula 4-3) is established.

[0062] Using known parameters from the DLCO calculation formula (Equation 4), the FAHe concentration and FACO concentration are back-calculated. VA (alveolar volume at standard state (STPD)) is calculated from the VI obtained during measurement and the predicted RV (residual volume) value as follows: VA = (VI + RV) ... (Equation 4-4) Furthermore, FAHe is calculated backward from the VA' formula, assuming VA=VA'. FAHe=FIHe×(VA' / VI)...(Formula 4-5) Use the calculated FAHe to calculate FACO(0). FACO(0)=(FAHe / FIHe)×FICO…(Formula 4-6)

[0063] The FACO is back-calculated using the DLCO prediction and BHT. D1=(VA×1000×60) / ((PB-47)×BHT) …(Formula 4-7) D2=exp(DLCO / D1) …(Formula 4-8) FACO=FACO(0) / D2 (Equation 4-9)

[0064] FIG. 11 is a flowchart corresponding to a DLCO test simulation. For example, when the examiner selects an object displayed on the display 56 that will execute a DLCO test simulation, the CPU 53 executes the simulation program and the DLCO test simulation is performed. A message prompting the examiner to prepare a four-gas mixture is displayed on the display 56 (S410). In addition, a "Start Preparation" button is displayed (S420) to fill the cylinder with gas for inhalation and prepare for CV measurement. From this information, the examiner can understand the type of gas to be used in DLCO measurement.

[0065] When the examiner operates the "Start preparation" button, the messages "Respiratory circuit ventilation in progress" and "Gas injection in progress" are displayed on the display 56 (S430). After the messages "Respiratory circuit ventilation in progress" and "Gas injection in progress" have finished being displayed (after gas injection has been completed), the examiner operates the "Start measurement" button displayed on the display 56 (S440), and the actual spirogram of the subject is measured by the flow sensor 10 provided in the respiratory function test simulator 1 and displayed on the display 56 (S450). Furthermore, the message "Please perform quiet ventilation" is displayed on the display 56 (S460).

[0066] Next, the CPU 53 displays on the display 56 a message urging the subject to exhale slowly to the maximum expiratory level, saying, "Exhale slowly until you can no longer exhale" (S490). Next, the CPU 53 displays on the display 56 a message urging the subject to inhale to the maximum inhalation level, saying, "Inhale quickly" (S500). This message encourages the subject to inhale the four-component gas mixture. Next, the CPU 53 displays on the display 56 a message instructing the subject to hold their breath for the set breath-holding time, saying, "If you can no longer inhale, hold your breath for 10 seconds" (S510).

[0067] Next, as described above, the CPU 53 calculates a predicted DLCO value corresponding to the subject's data based on a prediction formula. The predicted value may also be referred to as a reference value. The prediction formula may be, for example, that established by the Japanese Respiratory Society. Then, based on the calculated DLCO predicted value and the measured VI value, the CPU 53 calculates and generates a He concentration curve and a CO concentration curve using the formula described above (S520). As shown in FIG. 12, the values ​​of FIHe (a cylinder gas concentration set value) and FICO (a cylinder gas concentration set value) are used as the He concentration curve and the CO concentration curve corresponding to the breath-holding period during which the inspiratory flow measured by the flow sensor does not change, and the values ​​of FAHe and FACO calculated as described above are used as the He concentration curve and the CO concentration curve corresponding to the exhalation period after breath-holding. In the example shown in FIG. 12, the He and CO concentrations are normalized so that the relative changes in the He and CO concentrations can be understood. During the period during which the subject is holding their breath, FIHe is displayed as the He concentration and FICO is displayed as the CO concentration.

[0068] Next, the CPU 53 displays a message on the display 56 instructing the user to exhale in one gulp, saying, "Please exhale in one gulp" (S530). Accordingly, FAHe is displayed as the He concentration, and FACO is displayed as the CO concentration. Then, based on the fact that the expiratory flow has decreased to below a predetermined value (S540), the CPU 53 displays the test results (for example, the calculated DLCO predicted value and other test results that can be obtained in the DLCO test) on the display 56 (S550), and ends the DLCO test simulation.

[0069] In the above embodiment, FIHe is displayed as the He concentration curve and FICO is displayed as the CO concentration curve during the breath-holding period, and then FAHe is displayed as the He concentration curve and FACO is displayed as the CO concentration curve after exhalation (as if the curves were being drawn in real time in response to the flow). However, the present invention is not limited to this configuration. Instead, the He concentration curve and CO concentration curve may not be displayed during the breath-holding period, and a He concentration curve including FIHe and FAHe and a CO concentration curve including FICO and FACO may be displayed after a predetermined time has passed after exhalation (e.g., one to several seconds). This corresponds to the fact that, when measuring DLCO, sample gas from exhalation is sent to the analysis circuit (He concentration sensor, CO concentration sensor), and the first 750 mL is discarded and the gas concentration curves are displayed after the analysis is completed.

[0070] In this embodiment, as described above, the predicted DLCO value is used to generate the CO concentration curve, but by setting a DLCO value different from the predicted DLCO value (for example, a set DLCO value obtained by multiplying the predicted DLCO value by 0.8 as a coefficient), it is possible to reproduce the CO concentration when gas exchange function is impaired. In this way, the examiner can experience both good and bad examples of DLCO testing.

[0071] As described above, according to this embodiment, in order to allow a subject to acquire testing techniques for detailed testing that requires the functions of supplying test gas to the subject and detecting gas concentration, it is not necessary to actually use test gas, and it is possible to acquire the testing techniques at low cost.

[0072] Furthermore, the simulation function of this embodiment has a function of guiding the test procedures for detailed test items (e.g., FRC, CV, DLCO), allowing the user to learn the procedure for each test item. Also, by providing guidance on the type of gas used in the test and the breathing method that the subject should follow in accordance with the test procedure, the user can learn what gas should be prepared and how the subject should breathe for each test item.

[0073] Furthermore, the simulation function of this embodiment simulates gas concentration curves in detailed examinations based on actually measured respiratory flow rates or respiratory volumes (spirograms), making it possible to present data that is closer to the actual examination environment to the examiner, which provides a more realistic learning experience than simply presenting predetermined pseudo data. For example, if the examinee is made to breathe improperly just for training purposes, an appropriate gas concentration curve will not be obtained, and the examiner can recognize the importance of having the examinee breathe accurately.

[0074] Furthermore, in this embodiment, it is possible to perform simulations of good test results and ungood test results, so that the patient can become familiar with a variety of test results in clinical settings.

[0075] Figure 13 shows how the examiners' awareness changed after undergoing the FRC, CV, and DLCO test simulations (training). For each detailed test item, many examiners perceived the test as being difficult before the simulation. However, after the simulation, having experienced the test procedure and the breathing instructions the examinee should follow, and being presented with gas concentration curves based on actual measurement data, an increasing number of examiners perceived the test as being easier than expected. In this way, by eliminating the perception that the detailed test was difficult, the detailed test can be performed accurately using the detailed testing equipment without confusion in clinical settings.

[0076] As an example, as seen in the strained medical system during the COVID-19 pandemic, even if a considerable number of advanced medical devices are introduced, if there is a shortage of examiners who can properly operate them, the strained situation will not improve at all. From this perspective, it is desirable to make some progress in acquiring precision testing skills even before precision testing devices are introduced. The respiratory function test simulator of this embodiment also contributes to solving such problems.

[0077] (Other forms) In the above embodiment, an example has been described in which the respiratory function test simulator is a flow sensor-type spirometer. However, the respiratory function test simulator is not limited to this, and may be a precision testing device (air volume spirometer (rolling seal spirometer)) having a test gas supply function and a gas concentration detection function. For example, the precision testing device may be controlled in either (1) an actual measurement mode in which gas is actually supplied to the subject using the test gas supply function and the gas concentration is detected using the gas concentration detection function, or (2) a simulation mode in which no gas is supplied to the subject and no gas concentration is detected, and the simulation program of the above embodiment may be executed in (2) the simulation mode. Even in this configuration, since no actual test gas is used, it is possible to acquire precision testing techniques at low cost.

[0078] In the above embodiment, an example has been described in which the respiratory function test simulator simulates He concentration, N2 concentration, and CO concentration, but the respiratory function test simulator is not limited to this, and may also simulate NO (nitric oxide) in exhaled breath. For example, the NO concentration curve in exhaled breath may be simulated based on a relational expression that the lower the values ​​of spirometry items such as VC, FVC, forced expiratory volume in one second, and forced expiratory volume in one second, the higher the NO concentration in exhaled breath.

[0079] In the above embodiment, an example was described in which the parameters measurable by the respiratory function test simulator were respiratory flow rate or respiratory volume obtainable by a flow sensor, and the parameters to be simulated were gas concentrations. However, the present invention is not limited to this configuration. The parameters measurable by the respiratory function test simulator may be parameters other than respiratory flow rate or respiratory volume, and the parameters to be simulated may be parameters other than gas concentrations. For example, the chest and abdomen of a sleeping subject may be imaged with a video camera, and the respiratory rate and arterial oxygen saturation (SpO2) may be simulated based on a relationship between feature values ​​based on the actual images of the chest and abdomen and respiratory rate, arterial oxygen saturation (SpO2), and other parameters in a sleep apnea (PSG) test. This allows for the simulation of a remote PSG test without the need to install an actual PSG device on the subject's side.

[0080] In the above embodiment, an example of simulating the He concentration in functional residual capacity using the gas dilution method has been described, but the present invention is not limited to this. Alternatively, the intraoral pressure in a functional residual capacity test (body plethysmography) using a body plethysmograph (also called a body box) may be simulated. Furthermore, airway resistance using a body plethysmograph may be simulated. This makes it possible to acquire testing techniques for test items that use a body plethysmograph, without actually purchasing an expensive and large body plethysmograph.

[0081] In the above embodiment, the N2 concentration curve is generated by tracing a provisionally set, hidden N2 concentration curve in accordance with the exhaled air volume being measured. However, as shown in Figures 14 and 15, the provisionally set N2 concentration curve may also be constructed based on a predicted value of TLC (total lung capacity) and an average exhaled N2 concentration calculated from the TLC calculation formula.

[0082] The TLC calculation formula is shown below. TLC=[(VI×FAN2)-(Vd×FA'N2)]÷(FAN2-FEN2)…(Formula 5) where: VI: Intake volume Vd: Dead space volume (anatomical dead space volume + mechanical dead space volume) FAN2: Alveolar air N2 concentration (80%) FA'N2: Exhaled N2 concentration (corrected for dead space dilution) FEN2: Mean exhaled N2 concentration Let's say.

[0083] From equation (5), (Vd × FA'N2) can be omitted because it does not have a significant visual impact in a simulation that displays the N2 concentration curve in real time. (FAN2-FEN2)=(VI×FAN2)÷TLC…(Formula 5-1) FEN2=FAN2-((VI×FAN2)÷TLC) …(Formula 5-2) holds true.

[0084] Then, as shown in FIG. 14(a), an N2 concentration curve is constructed based on the mean exhaled N2 concentration calculated using Equation 5-2. At this stage, the N2 concentration curve shows a constant value corresponding to the calculated mean exhaled N2 concentration. Next, as shown in FIG. 14(b), the slope of the third phase is calculated based on the predicted ΔN2 value, and a third phase portion corresponding to the calculated slope is added to the constant value portion of FIG. 14(a), thereby increasing the N2 concentration from the third phase onward. Here, as the third phase and subsequent portions are added, the entire N2 concentration curve is adjusted toward the N2 concentration (e.g., shifted in the direction of decreasing N2 concentration) so that the mean exhaled N2 concentration is maintained at the calculated value without increasing above it. Furthermore, as shown in FIG. 14(c), a fourth phase portion is added to the third phase portion, thereby causing the N2 concentration in the fourth phase to rapidly increase corresponding to the end-tidal pressure. The onset (starting point) of the fourth phase may be set based on the predicted CV / VC and CV values. The waveform of the added fourth phase may be a waveform in which the N2 concentration increases at a constant rate relative to the gradient of the third phase.

[0085] Next, as shown in Figure 15(d), the first and second phases are added to the third and subsequent phases. The added first and second phase waveforms are, for example, stretched or shortened versions of standard waveform patterns prepared in advance. This completes the provisionally set N2 concentration curve.

[0086] As described above, the N2 concentration curve is generated by tracing a provisionally set, hidden N2 concentration curve in accordance with the exhaled air volume being measured (displaying the N2 concentration at a point corresponding to the exhaled air volume). Here, as shown in FIG. 15(e), during the CV simulation period (the period during which the subject is actually exhaling), a waveform simulating cardiac oscillation with a period of 60 to 90 bpm (1.0 to 1.5 Hz) may be displayed during the third phase display. For example, the period and amplitude of each waveform corresponding to cardiac oscillation may be determined based on random numbers generated within a predetermined range. The examiner can experience the appearance of cardiac oscillation during CV measurement. [Explanation of symbols]

[0087] 1. Respiratory function test simulator 10 Flow sensor 14 Resistor 5a First pressure detection port (pressure detection part) 5b Second pressure detection port (pressure detection part) 50 main body 51 Differential pressure sensor 52 A / D converter 53 CPU 54 RAM 55 ROM 56 Touch panel display 57 D / A converter 58 Speaker

Claims

1. A respiratory function test simulator that performs a simulation of a detailed test regarding gas concentration, A measurement unit for measuring respiratory flow or respiratory volume; an output unit that outputs guidance information corresponding to the detailed examination; a generating unit that generates simulation data related to the detailed examination based on the data measured by the measuring unit; A respiratory function test simulator comprising:

2. 2. The respiratory function test simulator according to claim 1, The guidance information includes information on a gas used in the detailed examination and information on breathing instructions to be given to the subject during the detailed examination. Respiratory function test simulator.

3. 2. The respiratory function test simulator according to claim 1, the generating unit generates a gas concentration curve based on the data measured by the measuring unit and a predetermined value corresponding to the detailed examination. Respiratory function test simulator.

4. 4. The respiratory function test simulator according to claim 3, The generation unit a first gas concentration curve can be generated based on the data measured by the measurement unit and a first predetermined value calculated based on a prediction formula corresponding to the detailed examination; generating a second gas concentration curve having a degree of suitability different from that of the first gas concentration curve based on the data measured by the measurement unit and a second predetermined value corresponding to the detailed inspection and different from the first predetermined value; Respiratory function test simulator.

5. A respiratory function test simulator according to any one of claims 1 to 4, The detailed test is a functional residual capacity test (FRC), the guidance information includes information notifying the use of He and information instructing the patient to perform quiet ventilation; The generating unit generates a gas concentration curve indicating a He concentration. Respiratory function test simulator.

6. A respiratory function test simulator according to any one of claims 1 to 4, The detailed examination is a closing volume examination (CV), The guidance information is ２ information instructing the user to exhale up to the maximum expiratory level, and information instructing the user to maintain the expiratory flow rate within a predetermined range; The generation unit is N ２ Generate a gas concentration curve showing the concentration, Respiratory function test simulator.

7. A respiratory function test simulator according to any one of claims 1 to 4, The detailed examination is a pulmonary function diffusion test (DLCO), The guidance information is ２、 N ２ information instructing the patient to inhale up to the maximum inspiratory position, information instructing the patient to hold their breath for a predetermined period at the maximum inspiratory position, and information instructing the patient to exhale in one breath, The generating unit generates a gas concentration curve indicating the CO concentration. Respiratory function test simulator.

8. A program executed by a respiratory function test simulator that executes a simulation of a detailed test regarding gas concentration, measuring a respiratory flow rate or a respiratory volume with a measuring unit; outputting guidance information corresponding to the detailed examination by an output unit; and generating, by a generating unit, simulation data relating to the detailed examination based on the data measured by the measuring unit.

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