Respiratory function measuring device

Abstract

To provide a respiratory function measuring device capable of coping with an increase in carbon dioxide concentration.SOLUTION: A respiratory function measuring device 1 includes: a sealed container part in which a piston 12 moves relative to a container part 11 according to an increase / decrease in the volume of gas put inside in an airtight manner; a first tube part 21, a second tube part 22, and a mouthpiece connection part 23 connected to the sealed container part; a fan 30 for generating an air flow in the first tube part 21, the second tube part 22, and the sealed container part; a carbon dioxide absorbent provided in an influence range of the air flow; a potentiometer 15 for generating output according to the volume of the gas in the sealed container part; an oxygen cylinder B2 for supplying oxygen inside the sealed container part according to the volume of carbon dioxide absorbed by the absorbent; a supply part 40; a connection tube 50; a determination part for performing determination on the amount of oxygen supplied inside the sealed container part; and a notification part for performing notification according to a result of the determination by the determination part.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a respiratory function measuring device. [Background technology]

[0002] As an apparatus capable of measuring functional residual capacity (FRC) as a respiratory function measurement, an apparatus capable of performing the helium closed circuit method is known (for example, Patent Document 1). In the helium closed circuit method, a mixed gas of air and helium is prepared in advance in the respiratory function measuring device, and the subject is made to breathe the mixed gas. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2017-086704 Summary of the Invention [Problem to be solved by the invention]

[0004] Respiratory function measuring devices that perform FRC measurements using the helium closed circuit method are equipped with a fan that automatically generates an airflow between the ventilation tube and the respiratory function measuring device to prevent the subject's exhaled air from stagnating in the ventilation tube between the subject's mouth and the respiratory function measuring device. However, if the fan's rotation speed unintentionally decreases due to reasons such as fan failure, it becomes difficult to perform FRC measurements correctly. In addition to this, deterioration of the carbon dioxide absorbent installed in the airflow path can also unintentionally increase the carbon dioxide concentration in the ventilation tube, causing subjects to experience breathing difficulties. Therefore, a mechanism that can respond to increases in carbon dioxide concentration was needed.

[0005] The present invention has been made in view of the above-mentioned problems, and has an object to provide a respiratory function measuring device that can respond to an increase in carbon dioxide concentration. [Means for solving the problem]

[0006] In order to achieve the above object, the respiratory function measuring device of the present invention comprises a container-shaped fixed part, and a movable part that cooperates with the fixed part to seal gas inside and is provided so as to be movable relative to the fixed part, the movable part moving relative to the fixed part in response to an increase or decrease in the volume of gas sealed inside the sealed container part, two tube parts connected to the fixed part to form a gas flow path leading to the inside of the sealed container part, and a respiratory function measuring device that is interposed between the mouth of a subject and the two tube parts during respiratory function measurement and that detects changes in air pressure due to mouth breathing of the subject and transmits the changes in air pressure into the two tube parts. an airflow generating unit provided in the gas flow path for generating an airflow in the two pipes and in the sealed container; an absorbent provided within the range of influence of the airflow for absorbing carbon dioxide; an information output unit for generating an output showing information corresponding to the volume of gas in the sealed container; an oxygen supply unit for supplying oxygen into the sealed container in accordance with the volume of carbon dioxide absorbed by the absorbent; a determination unit for determining the amount of oxygen supplied into the sealed container; and an alarm unit for issuing an alarm in accordance with the determination result of the determination unit.

[0007] This makes it possible to determine whether carbon dioxide absorption by the absorbent is occurring normally based on the oxygen supply amount corresponding to the carbon dioxide absorption by the absorbent that occurs during respiratory function measurements such as FRC measurements. In other words, if the oxygen supply amount corresponding to the volume of absorbed carbon dioxide is lower than normal, it can be concluded that carbon dioxide absorption is stalled for some reason. A notification is then issued based on the determination result of the determination unit, allowing for appropriate action to be taken according to the notification content. For example, the operator of the respiratory function measuring device can temporarily halt the respiratory function measurement and then perform work to normalize carbon dioxide absorption and oxygen supply, such as inspecting the airflow generating unit or absorbent. Therefore, according to the present invention, it is possible to respond to an increase in carbon dioxide concentration.

[0008] In a preferred embodiment of the respiratory function measuring apparatus, the notification unit issues a notification when the amount of oxygen supplied per unit time is equal to or less than a threshold value.

[0009] This allows notification to be made based on a clear criterion, that is, the relationship between the amount of oxygen supplied per unit time and a predetermined threshold value.

[0010] In a preferred embodiment of the respiratory function measuring device, when the amount of oxygen supplied per unit time falls below the threshold value after a predetermined time or more has elapsed from a predetermined point in time, the notification unit issues an alarm corresponding to an abnormality in the airflow generating unit.

[0011] This can prevent subjects from experiencing breathing difficulties during respiratory function measurements such as FRC measurements.

[0012] In a preferred embodiment of the respiratory function measuring device, the notification unit issues a warning indicating an abnormality in the airflow generating unit if the amount of oxygen supplied per unit time from the specified time point until the specified time has elapsed is equal to or less than the threshold value.

[0013] This makes it easier to prevent subjects undergoing respiratory function measurements such as FRC measurements from experiencing breathing difficulties.

[0014] In a preferred embodiment of the respiratory function measuring device, the determination unit calculates an average value of the oxygen supply amount per unit time from the relationship between the elapsed time from the predetermined time point and the oxygen supply amount until a predetermined time has elapsed from the predetermined time point, and regards the calculated average value as the oxygen supply amount per unit time.

[0015] This allows a value that can be considered to be the oxygen supply amount per unit time to be calculated before the predetermined time has elapsed, thereby enabling a determination regarding the oxygen supply amount to be supplied into the sealed container and a notification based on the determination result to be made at an earlier point in time.

[0016] In a preferred embodiment of the respiratory function measuring device, the determination unit makes a determination based on the relationship between the elapsed time from a predetermined point in time and the amount of oxygen supplied from that predetermined point in time, and the notification unit issues a notification if it is determined that the amount of oxygen supplied is insufficient for the elapsed time.

[0017] This allows for determination and notification based on the relationship between the elapsed time from a predetermined time point and the oxygen supply amount from the predetermined time point. For example, by setting the predetermined time as the start time of respiratory function measurement, it is possible to determine the oxygen supply amount based on the relationship between the total elapsed time since the start of respiratory function measurement and the total oxygen supply amount, and to notify based on the result of this determination.

[0018] In a preferred embodiment of the respiratory function measuring device, the oxygen supply unit includes an electromagnetic valve provided in a gas flow path connecting the oxygen cylinder and the sealed container unit so as to be able to open and close the flow path, and a flow rate acquisition unit that acquires information indicating the flow rate of gas flowing through the gas flow path connecting the oxygen cylinder and the sealed container unit, and the determination unit calculates the amount of oxygen supplied per unit time based on the flow rate indicated by the information acquired by the flow rate acquisition unit.

[0019] This allows more accurate acquisition of information indicating the amount of oxygen supplied by the oxygen supply process.

[0020] In a preferred embodiment of the respiratory function measuring device, a helium supply unit is provided for supplying helium into the sealed container unit.

[0021] This makes it easier to perform respiratory function measurements that use helium, such as FRC measurements. [Effects of the Invention]

[0022] According to the present invention, a respiratory function measuring device that can respond to an increase in carbon dioxide concentration can be provided. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. 1 is a schematic diagram showing the main configuration of a respiratory function measuring device. [Figure 2] FIG. 2 is a block diagram showing the main components related to information processing performed by the respiratory function measuring device. [Figure 3] FIG. 3 is a graph showing the change in volume position during FRC measurements under hypothetical conditions. [Figure 4] FIG. 4 is a schematic graph showing the amount of oxygen supply required as the FRC measurement progresses. [Figure 5] FIG. 5 is a graph showing the transition of the volume position when oxygen is supplied as the FRC measurement progresses, and events related to the supply of oxygen. [Figure 6] FIG. 6 is a schematic diagram showing an example of the display output content when FRC measurement is performed. [Figure 7] FIG. 7 is a schematic diagram showing an example of the display output content when a warning is issued during FRC measurement. [Figure 8] FIG. 8 is a schematic diagram showing an example of the display output content when an alarm is issued during FRC measurement. [Figure 9] FIG. 9 is a flowchart showing the flow of processing related to the detection of a fan abnormality in FRC measurement performed by the respiratory function measuring device. [Figure 10] FIG. 10 is a flowchart showing the flow of processing related to detection of a shortage of oxygen supply amount in FRC measurement when a determination is made based on the relationship between the time elapsed from a predetermined time point and the oxygen supply amount from the predetermined time point. [Figure 11] FIG. 11 is a flowchart showing the process flow for detecting a shortage of oxygen supply amount in FRC measurement when a determination based on the relationship between the elapsed time from a predetermined time point and the oxygen supply amount from the predetermined time point is further incorporated into the process flow described with reference to FIG. [Figure 12] FIG. 12 is a graph showing the rate of increase in helium concentration detected by the helium concentration sensor when helium is supplied from a helium cylinder via the supply unit into the container before FRC measurement is performed. [Figure 13] FIG. 13 is a block diagram showing a respiratory function measuring device equipped with a fan monitoring unit. [Figure 14] FIG. 14 is a schematic diagram showing the main components of a respiratory function measuring device provided with a one-way valve. [Figure 15] FIG. 15 is a block diagram showing an example of the configuration when an oxygen supply amount monitoring program that does not use a flow meter is adopted. [Figure 16] FIG. 16 is a schematic diagram showing an example in which some of the various items described with reference to FIGS. 1 to 15 are modified. [Figure 17] FIG. 17 shows the calorie consumption per hour and the oxygen intake per hour according to the combination of age and sex of a person. DETAILED DESCRIPTION OF THE INVENTION

[0024] Modes (embodiments) for carrying out the present invention will be described in detail with reference to the drawings. The present invention is not limited to the contents described in the following embodiments. Furthermore, the components described below include those that can be easily imagined by a person skilled in the art and those that are substantially the same. Furthermore, the components described below can be combined as appropriate.

[0025] FIG. 1 is a schematic diagram showing the main components of a respiratory function measuring device 1. The respiratory function measuring device 1 is a device designed to measure the respiratory function of a subject. Respiratory function measurements that can be performed with the respiratory function measuring device 1 include at least FRC measurement using a helium closed circuit method. As shown in FIG. 1, the respiratory function measuring device 1 includes a housing unit 10, a conduit unit 20, a supply unit 40, and a helium concentration detection unit 60.

[0026] The housing 10 includes a container 11, a piston 12, a flexible membrane 13, a shaft 14, a potentiometer 15, a tube connection 16, a tube connection 17, and an absorbent container 18. The container 11 is a part of the housing 10 that is provided so as to have a hollow interior.

[0027] The piston 12 is provided so that its position can be changed relative to the container portion 11. A change in the position of the piston 12 relative to the container portion 11 changes the internal volume of the container portion 11. Specifically, the piston 12 is connected to the container portion 11 via a guide rail mechanism within the container portion 11 and is provided so that it can move linearly relative to the container portion 11. In FIG. 1, the direction of linear movement of the piston 12 by the guide rail mechanism is schematically shown by a dashed line GL. More specifically, the cross-sectional shape of the piston 12 in a direction perpendicular to the linear movement axis of the piston 12 is circular, but this is not limited to a circular shape and other shapes may be used.

[0028] The flexible membrane 13 is a flexible member that seals the gap between the outer periphery of the piston 12 and the container 11. The flexible membrane 13 is provided in advance so as to correspond to the linear movement range of the piston 12, which is defined by the above-mentioned guide rail mechanism. Therefore, gas does not leak from the space within the container 11 to the piston 12 side when the position of the piston 12 relative to the container 11 is changed.

[0029] Here, the container 11 functions as a fixed container-like part capable of storing gas inside. The piston 12 and flexible membrane 13 cooperate with the fixed part to seal the gas inside and function as a movable part that is movable relative to the fixed part. The container 11, piston 12, and flexible membrane 13 form a sealed container part in which the movable part moves relative to the fixed part in response to an increase or decrease in the volume of the gas sealed inside.

[0030] The shaft 14 is a rod-shaped member fixed to the piston 12. The potentiometer 15 detects the position of the shaft 14. Specifically, the potentiometer 15 is, for example, a linear potentiometer. The position of the shaft 14 corresponds to the position of the piston 12 relative to the container part 11. In other words, the potentiometer 15 can output information indicating the position of the piston 12 relative to the container part 11 by detecting the position of the shaft 14. Note that the potentiometer 15 may also be an encoder that functions in a similar manner.

[0031] The pipe connection parts 16 and 17 are tubular structures whose interiors are continuous with the space within the container part 11. The absorbent container 18 is a container-like member interposed between the pipe connection part 16 and the container part 11 and provided to allow ventilation between the pipe connection part 16 and the container part 11. The absorbent container 18 contains an absorbent for carbon dioxide. The absorbent is, for example, soda lime, but is not limited to this, and other structures that function in a similar manner may be used.

[0032] The duct section 20 includes a first duct section 21, a second duct section 22, a mouthpiece connection section 23, etc. In the example shown in FIG. 1, the duct section 20 further includes a fan 30, but the fan 30 may be provided in another location. For example, the fan 30 may be provided either between the duct connection section 16 and the absorbent container 18 or between the absorbent container 18 and the container section 11. Furthermore, an airflow generating section such as the fan 30 may be disposed on the second duct section 22 side as shown in FIG. 1, or on the first duct section 21 side as shown in FIG. 16, which will be described later.

[0033] The first tube section 21 is a tubular member connected to the tube connection section 17. The second tube section 22 is a tubular member connected to the tube connection section 16 via the fan 30. The mouthpiece connection section 23 is a branched tubular member formed so that the duct branches into the first tube section 21 and the second tube section 22. In other words, the duct in the first tube section 21 and the duct in the second tube section 22 are continuous via the mouthpiece connection section 23. More specifically, the mouthpiece connection section 23 has a structure as a so-called three-way cock. The mouthpiece connection section 23 is configured to be able to switch between blocking and opening the air passage on the mouthpiece 24 side. During respiratory function measurement such as FRC measurement, the mouthpiece connection section 23 is set so that the gas passage in the mouthpiece 24 is continuous with the first tube section 21 and the second tube section 22.

[0034] Here, the first pipe section 21 and the second pipe section 22 function as two pipe sections that are connected to the sealed container section constituted by the container section 11, the piston 12 and the flexible membrane 13 in this embodiment, and form a gas flow path leading to the inside of the sealed container section.

[0035] 1 and 14 described later is interposed between the second pipe section 22 and the pipe connection section 16, but as mentioned above, it may be provided in another location. The fan 30 includes a housing provided to form a conduit continuous with the conduit in the second pipe section 22 and the conduit in the pipe connection section 16, and an operating body that applies a biasing force to the gas in the conduit in the housing in a direction from the second pipe section 22 side toward the pipe connection section 16 side. The operating body is, for example, a rotating blade (fan), but is not limited to a blade and can be changed as appropriate as long as it is configured to apply a biasing force to the gas.

[0036] The biasing force generated by the fan 30 generates an airflow Ve11 that flows from the fan 30 through the pipe connection portion 16 and the absorbent container 18 toward the inside of the container 11. The airflow Ve11 acts to lower the air pressure on the second pipe 22 side across the fan 30 and to raise the air pressure on the pipe connection portion 16 side. The space connected to the inside of the container 11 is sealed except for the other end of the mouthpiece 24, which will be described later. Therefore, the airflow Ve11 also acts as a force that generates an airflow Ve12. The airflow Ve12 flows from the inside of the container 11 toward the inside of the pipe connection portion 17. The airflow Ve12 causes the gas in the container 11 to flow into the first pipe 21 via the pipe connection portion 17. As described above, the first pipe 21 and the second pipe 22 are connected, and thus the air pressure in the pipe 20 is balanced by the airflow Ve12 being generated in response to the air pressure in the second pipe 22 being lowered by the airflow Ve11.

[0037] Therefore, in the embodiment, the fan 30 is provided in the gas flow path leading to the inside of the sealed container, and functions as an airflow generating unit that generates airflow within two pipes that are connected to the fixed part of the sealed container and form the gas flow path leading to the inside of the sealed container, and within the sealed container that is composed of the container part 11, the piston 12, and the flexible membrane 13 in the embodiment. The airflow referred to here is at least the airflow Ve11. The airflow Ve12 can also be considered to fall under this airflow. The absorbent in the absorbent container 18 is provided within the range of influence of the airflow and functions as an absorbent that absorbs carbon dioxide. Hereinafter, when simply referred to as an absorbent, it refers to the absorbent in the absorbent container 18.

[0038] A mouthpiece 24 is detachably attached to the mouthpiece connector 23. The mouthpiece 24 is a member having a ventilated tube portion formed therein. One end of the tube portion of the mouthpiece 24 is provided so as to be able to fit into the mouthpiece connector 23. The other end of the tube portion of the mouthpiece 24 is shaped so as to be able to be held in the mouth of the human HU. The human HU is a human who will be the subject of respiratory function measurement.

[0039] When the human HU breathes through his / her mouth while holding the mouthpiece 24, the volume of gas sealed within the housing 10 changes via the conduit 20. Specifically, when the human HU inhales, gas moves from the container 11 toward the lungs of the human HU via the tube connection 17, the first tube 21, the mouthpiece connection 23, and the mouthpiece 24. This gas movement reduces the volume of gas within the container 11. The piston 12 moves toward the absorbent container 18 in response to the pressure difference between the inside and outside of the housing 10 that occurs as the volume of gas within the container 11 decreases. That is, the piston 12 moves to reduce the volume within the container 11 by an amount corresponding to the decrease in the volume of gas within the container 11 caused by the inhalation. The movement of the piston 12 that occurs with the inhalation causes a change in the position of the shaft 14, which is detected by the potentiometer 15. That is, the movement of the piston 12 that occurs with the generation of exhalation is detected by the potentiometer 15.

[0040] Meanwhile, when the human HU exhales, the exhaled air is sent into the mouthpiece connector 23 via the mouthpiece 24, causing a gas movement that flows into the container 11 via the second tube 22, the fan 30, the tube connector 16, and the absorbent container 18. This gas movement increases the volume of gas in the container 11. The piston 12 moves toward the potentiometer 15 in response to the pressure difference between the inside and outside of the housing 10 that occurs with this increase in the volume of gas in the container 11. That is, the piston 12 moves to increase the volume of the container 11 by an amount corresponding to the increase in the volume of gas in the container 11 caused by the exhaled air. The movement of the piston 12 that occurs with the exhaled air causes a change in the position of the shaft 14, which is detected by the potentiometer 15. That is, the movement of the piston 12 that occurs with the exhaled air is detected by the potentiometer 15. The output of potentiometer 15 changes according to the capacity (volume) of the gas in container 11, and therefore correlates with the capacity (volume) of the gas in container 11. In this embodiment, the output of potentiometer 15 is referred to as volume. The reciprocating movement of piston 12 caused by the alternating occurrence of the above-mentioned inhalation and exhalation is reflected in a change in volume.

[0041] Therefore, during respiratory function measurement, mouthpiece connection part 23 functions as a branch pipe part that is interposed between the subject's mouth and two pipe parts, which in this embodiment are first pipe part 21 and second pipe part 22, and that brings changes in air pressure caused by the subject's mouth breathing into the two pipe parts. Also, mouthpiece 24 functions as a mouthpiece that is detachable from the branch pipe part.

[0042] The supply section 40 includes pipes 43 and 44 , a flow meter 45 , a pipe 46 , a valve 47 , a solenoid valve 48 and a branch pipe 49 .

[0043] Pipe 43 is a tubular member connected to a helium supply source. In FIG. 1 and FIG. 14 (described later), a helium cylinder B1 is shown as an example of a helium supply source. Helium cylinder B1 is a cylinder filled with helium (He) gas used in FRC measurement. Valve 47 is a needle valve interposed between pipe 43 and branch pipe 49 and provided to be able to control the amount of helium flowing from pipe 43 into branch pipe 49. Note that the helium supply source may be configured other than helium cylinder B1, such as helium supply piping provided in a building such as a hospital.

[0044] Pipe 44 is a tubular member connected to an oxygen supply source. In FIG. 1 and FIG. 14 described later, oxygen cylinder B2 is illustrated as an example of an oxygen supply source. Oxygen cylinder B2 is a cylinder filled with oxygen gas used in FRC measurement. The oxygen supply source may be configured as an oxygen supply pipe installed in a building such as a hospital, or other configuration other than oxygen cylinder B2. Flow meter 45 is a flow meter interposed between pipe 44 and pipe 46 and is capable of measuring the amount of oxygen flowing from pipe 44 into pipe 46. Pipe 46 is a tubular member interposed between flow meter 45 and solenoid valve 48. Solenoid valve 48 is a solenoid valve interposed between pipe 46 and branch pipe 49 and is capable of controlling the amount of oxygen flowing from pipe 46 into branch pipe 49.

[0045] More specifically, the solenoid valve 48 of the embodiment is a solenoid valve having a so-called needle shape. Therefore, the flow rate of oxygen from the oxygen cylinder B2 through the pipe 44, flow meter 45, and solenoid valve 48 to the branch pipe 49 depends on the supply pressure from the oxygen cylinder B2 and the resistance generated by the shape (needle) of the solenoid valve 48 in the ventilation path. Note that the specific shape of the solenoid valve 48 is not limited to this and can be changed as appropriate. For example, the needle and the movable part serving as the solenoid valve may be separate bodies.

[0046] Branch pipe 49 is a so-called bifurcated tubular member. One of the bifurcated ends of branch pipe 49 is connected to solenoid valve 48, and the other is connected to valve 47. Branch pipe 49 is also connected to connecting pipe 50. Connecting pipe 50 is a tubular member that connects branch pipe 49 and container 11. In other words, supply unit 40 is configured to be able to supply helium from helium cylinder B1 and oxygen from oxygen cylinder B2 into container 11 via connecting pipe 50.

[0047] Therefore, in this embodiment, supply unit 40 connected to oxygen cylinder B2 and connecting pipe 50 function as an oxygen supply unit that supplies oxygen into the sealed container constituted by container 11, piston 12, and flexible membrane 13. More specifically, in supply unit 40, pipe 44, flow meter 45, pipe 46, solenoid valve 48, and branch pipe 49 function as the oxygen supply unit. The oxygen supply unit includes solenoid valve 48, which is provided in a gas flow path connecting oxygen cylinder B2 and the sealed container constituted by container 11 and piston 12 in this embodiment, and is capable of opening and closing the flow path, and flow meter 45, which detects the flow rate of gas flowing through the gas flow path connecting oxygen cylinder B2 and the sealed container.

[0048] In this embodiment, supply unit 40 connected to helium cylinder B1 and connecting pipe 50 function as a helium supply unit that supplies helium into the sealed container portion formed by container portion 11, piston 12, and flexible membrane 13. More specifically, of supply unit 40, pipe 43, valve 47, and branch pipe 49 function as the helium supply unit.

[0049] The helium concentration detection unit 60 includes a helium concentration sensor 61, a pump 62, and pipes 63, 64, and 65. The helium concentration sensor 61 detects the concentration of helium contained in the gas. The pump 62 is a pump that generates an airflow within the helium concentration detection unit 60. The pipes 63, 64, and 65 are tubular members. The pipe 63 connects the helium concentration sensor 61 and the pump 62. The pipe 64 connects the helium concentration sensor 61 and the container unit 11. The pipe 65 connects the pump 62 and the container unit 11.

[0050] In this embodiment, pump 62 generates a gas flow that passes from inside container 11 through pipe 65, pump 62, pipe 63, helium concentration sensor 61, and pipe 64 and returns to container 11. This allows helium concentration sensor 61 to detect the helium concentration contained in the gas sealed inside container 11. Note that the gas flow generated by helium concentration sensor 61 may be in the opposite direction to that described above.

[0051] The space within the housing 10, formed by the container 11, the pipe connection 16, the pipe connection 17, and the absorbent container 18, is continuous with the spaces within the pipe line 20, the connecting pipe 50, and the helium concentration detection unit 60. The space within the connecting pipe 50 also connects the space within the supply unit 40 with the gas space within the housing 10. This continuous space is sealed by these configurations to prevent gas from flowing in or out from other locations, except for the gas flowing in or out via the mouthpiece 24. Therefore, as described above, the piston 12 moves in response to the breathing of the human HU.

[0052] 2 is a block diagram showing the main components related to information processing performed by the respiratory function measuring device 1. The respiratory function measuring device 1 includes an information processing unit 70. As will be described later, the information processing unit 70 functions as a determination unit and a notification unit. The information processing unit 70 includes a calculation unit 71, a storage unit 72, an input unit 73, an output unit 74, and an interface 75.

[0053] The calculation unit 71 includes a calculation circuit that functions as a CPU (Central Processing Unit) and performs various processes related to the operation of the respiratory function measuring device 1. The storage unit 72 stores software programs that are read out during processing performed by the calculation unit 71. Hereinafter, the term "program" refers to such software programs. The storage unit 72 shown in FIG. 2 stores an FRC measurement program 721, an oxygen supply amount monitoring program 722, and a fan abnormality detection program 723.

[0054] The FRC measurement program 721 is a program for performing FRC measurement with the respiratory function measuring device 1. The oxygen supply amount monitoring program 722 is a program for monitoring the oxygen supply amount during FRC measurement. The fan abnormality detection program 723 is a program for detecting an abnormality in the fan 30.

[0055] The input unit 73 includes an input device for receiving input from a user. Examples of such an input device include a keyboard and a mouse, but the input device is not limited to these and may include a touch panel that is integral with the output unit 74.

[0056] The output unit 74 performs output according to the processing content by the calculation unit 71. The output unit 74 includes, for example, a display device such as a liquid crystal display, an audio output device such as a speaker, etc., but is not limited to these, and may include a device for performing output in other forms. In the following description of the embodiment, it is assumed that the output unit 74 includes at least a display device.

[0057] The interface 75 is an interface for electrically connecting the information processing unit 70 with various components provided in the respiratory function measuring device 1. In the example shown in Fig. 2, the potentiometer 15, the helium concentration sensor 61, the solenoid valve 48, and the flow meter 45 are connected to the information processing unit 70 via the interface 75.

[0058] Before describing oxygen supply control in FRC measurement, an outline of FRC measurement performed using the respiratory function measuring device 1 in this embodiment will be described. In FRC measurement using the helium closed-circuit method, air (hereinafter referred to as the mixed gas) mixed with a certain percentage of helium (e.g., approximately 10%) is filled into the container 11 before starting. In FRC measurement, the human HU breathes the mixed gas in the container 11 through his or her mouth while holding the mouthpiece 24. This causes helium contained in the mixed gas to enter the human HU's lungs, reducing the percentage of helium in the mixed gas. In this embodiment, the functional residual capacity of the human HU is measured based on the degree of reduction in the percentage of helium in the mixed gas. In this embodiment, the helium concentration sensor 61 is connected to the information processing unit 70 via the interface 75 in order to detect the degree of reduction in the percentage of helium when performing FRC measurement.

[0059] Next, oxygen supply control in FRC measurement will be described with reference to FIGS. 3 to 5. FIG. 3 is a graph showing changes in volume position during FRC measurement under hypothetical conditions. As described above, volume refers to the position of the shaft 14 indicated by the output of the potentiometer 15. Here, the position of the shaft 14 indicated by the output of the potentiometer 15 corresponds to the position of the piston 12 relative to the container 11. Therefore, the volume position here refers to the position of the piston 12 relative to the container 11. In the graphs shown in FIGS. 3 and 5, the volume position transitions (rises) upward along the vertical axis in response to the movement of the piston 12 accompanying inspiration. Also, in these graphs, the volume position transitions (descends) downward along the vertical axis in response to the movement of the piston 12 accompanying expiration. Also, the horizontal axis in these graphs indicates the passage of time. Here, the potentiometer 15 functions as an information output unit that generates an output indicating information corresponding to the volume of gas in the sealed container, which is composed of the container 11, the piston 12, and the flexible membrane 13 in this embodiment.

[0060] In the following explanation, it is assumed that there is no leakage of the mixed gas between the mouth of the human HU and the mouthpiece 24. In other words, it is assumed that there is no decrease in the mixed gas in the container 11 due to gas leakage from the mouthpiece 24. Under these conditions, the increase or decrease in the mixed gas in the container 11 accompanying the breathing of the human HU (see FIG. 1) will be as shown in waveform W1 in FIG. 3, unless the absorption of carbon dioxide by the absorbent is taken into account. In other words, if the absorption of carbon dioxide by the absorbent is not taken into account, the rise in the volume position accompanying the inhalation of the human HU and the fall in the volume position accompanying the exhalation of the human HU are balanced. Therefore, the straight line L1 tracing the exhalation peak in waveform W1 does not show either a rise or a fall in the volume position.

[0061] However, the respiratory function measuring device 1 is provided with an absorbent container 18. The absorbent in the absorbent container 18 absorbs carbon dioxide contained in the exhaled breath. Furthermore, the exhaled breath of a human HU contains more carbon dioxide than the inhaled gas. That is, the amount of carbon dioxide in the breathed mixed gas increases after breathing compared to before breathing. This increased amount of carbon dioxide is absorbed by the absorbent. Therefore, as the absorbent absorbs carbon dioxide in proportion to the volume of carbon dioxide produced each time the human HU breathes, the volume of the mixed gas after breathing decreases compared to before breathing. As such, assuming no oxygen is supplied, the volume of the mixed gas in the container 11 decreases as the FRC measurement progresses. As the volume of the mixed gas decreases, the position of the piston 12 relative to the container 11 shifts toward the absorbent container 18 over time. That is, as the absorbent absorbs carbon dioxide, the volume of the mixed gas decreases and the volume position rises. When the volume of the mixed gas in the container 11 decreases as the FRC measurement progresses, the volume position tends to rise overall over time, as shown by waveform W2 in Figure 3. This is because the position of the piston 12 relative to the container 11 shifts toward the absorbent container 18 over time as the volume of the mixed gas in the container 11 decreases. Therefore, line L2, which traces the peak of the exhaled breath in waveform W2, indicates the rise in the volume position corresponding to the amount of carbon dioxide absorbed by the absorbent over time. In other words, the difference between lines L1 and L2 at a given point in time indicates the amount of carbon dioxide absorbed by the absorbent.

[0062] 3 represents a hypothetical condition in which no oxygen is supplied. In reality, oxygen is supplied from oxygen cylinder B2 into container 11 via supply unit 40 and connecting pipe 50 as the FRC measurement progresses.

[0063] Figure 4 is a schematic graph showing the amount of oxygen required as FRC measurement progresses. Assuming that no oxygen is being supplied, assume that a line L3 is established, in which the volume position rises from position V1 to position V2 between time t1 and time t2. In this case, the volume of gas corresponding to the difference P between the volume positions V1 and V2 is the volume of oxygen that should be supplied during the time from time t1 to time t2.

[0064] The supply of oxygen in an amount corresponding to the difference P is not carried out all at once at timing t2, but is carried out intermittently as the FRC measurement progresses. The supply of oxygen carried out as the FRC measurement progresses will be described below with reference to FIG.

[0065] 5 is a graph showing the transition of the volume position when oxygen is supplied as the FRC measurement progresses and events related to the oxygen supply. As described above, as the FRC measurement progresses, the carbon dioxide contained in the exhaled breath is absorbed by the absorbent, causing the volume position indicated by waveform W3 to generally show an upward trend. Therefore, at a certain point after the start of the FRC measurement, the downward peak of the volume position indicating the peak of the exhaled breath reaches a position equal to or greater than threshold value Th1. In FIG. 5, for example, after the start of the FRC measurement, the downward peak of the volume position indicating the peak of the exhaled breath first reaches a position equal to or greater than threshold value Th1 at timing T11.

[0066] In this embodiment, oxygen is supplied when the peak of the downward movement of the volume position, which indicates the peak of exhalation, reaches a position equal to or greater than the threshold value Th1. Here, oxygen is supplied from the oxygen cylinder B2 into the container 11 via the supply unit 40 and the connecting tube 50, and the volume of the mixed gas in the container 11 increases by the amount of oxygen supplied. As the volume of the mixed gas increases, the position of the piston 12 relative to the container 11 shifts toward the shaft 14 over time. That is, as oxygen is supplied, the volume position descends. This oxygen supply continues until the peak of the downward movement of the volume position, which indicates the peak of exhalation occurring after that point, falls below the threshold value Th1. For example, the oxygen supply process P1, which started at time T11, continues until time T12, and the peak of the downward movement of the volume position, which indicates the peak of exhalation, falls below the threshold value Th1 at time T12. Therefore, the oxygen supply process P1, which started at time T11, is stopped at time T12.

[0067] In the waveform W3 shown in Fig. 5, the peaks of the downward movement of the volume position, which indicates the peak of exhalation, are at or above the threshold value Th1 at times T11, T21, T31, and T41. Timing T21 is later than time T12. Timing T31 is later than time T11 and T21. Timing T41 is later than time T11, T21, and T31. In addition, in the waveform W3, the oxygen supply process P2, which started at time T21, continues until time T22, so that the peaks of the downward movement of the volume position, which indicates the peak of exhalation, are below the threshold value Th1 at time T22. In addition, the oxygen supply process P3, which started at time T31, continues until time T32, so that the peaks of the downward movement of the volume position, which indicates the peak of exhalation, are below the threshold value Th1 at time T32. Furthermore, the oxygen supply process P4, which started at time T41, continues until time T42, so that the peak of the downward movement of the volume position, which indicates the peak of the exhalation, is below the threshold value Th1 at time T42. Time T22 is later than time T21 and earlier than time T31. Time T32 is later than time T31 and earlier than time T41.

[0068] 3 and 5, the functions of detecting the volume position and implementing the oxygen supply process such as the oxygen supply processes P1, P2, P3, and P4 are performed by the information processing unit 70. Specifically, the processing contents for realizing the functions of detecting the volume position and implementing the oxygen supply process such as the oxygen supply processes P1, P2, P3, and P4 are included in the FRC measurement program 721. The calculation unit 71 executes and processes the volume position detection and the oxygen supply process associated with the FRC measurement.

[0069] More specifically, the potentiometer 15 detects the volume position associated with the FRC measurement. The calculation unit 71 acquires the output of the potentiometer 15 connected via the interface 75. The calculation unit 71 identifies the timing at which the volume position, indicating the peak of exhalation, decreases, based on the relationship between the passage of time and the transition of the volume position indicated by the output of the potentiometer 15. The calculation unit 71 compares the volume position at that timing with a threshold value Th1. If the volume position at that timing is equal to or greater than the threshold value Th1, the calculation unit 71 operates the solenoid valve 48 to open the gas flow path within the solenoid valve 48. This initiates the oxygen supply process. Furthermore, after the start of the oxygen supply process, the calculation unit 71 operates the solenoid valve 48 to close the gas flow path within the solenoid valve 48 when the volume position at the timing of the peak decrease in the volume position becomes lower than the threshold value Th1. This completes the oxygen supply process. The flow rate of oxygen flowing through the supply unit 40 in the oxygen supply process is measured by the flow meter 45. Information indicating the flow rate of oxygen measured by the flow meter 45 is output to the information processing unit .

[0070] During FRC measurement, a process for calculating the oxygen supply amount is performed. In this embodiment, a process for calculating the oxygen supply amount per unit time is performed. In FIG. 5, the predetermined time for calculating the oxygen supply amount is exemplified as a predetermined time UT. The predetermined time UT is, for example, 30 seconds. The unit time is, for example, 1 minute. The length of the predetermined time UT and the length of the unit time are not limited to these and can be changed as appropriate.

[0071] The volume of oxygen supplied by the oxygen supply process carried out during the predetermined time UT is measured by the flow meter 45. For example, in the example shown in Fig. 5, oxygen supply processes P1, P2, P3, and P4 occur as oxygen supply processes. The flow meter 45 measures the flow rate of oxygen flowing through the flow meter 45 in each of the oxygen supply processes P1, P2, P3, and P4, and outputs information indicating the measured flow rate.

[0072] The information processing unit 70 is responsible for calculating the oxygen supply amount per unit time based on the output of the flowmeter 45. Specifically, the oxygen supply amount monitoring program 722 includes the process of calculating the oxygen supply amount per unit time based on the output of the flowmeter 45. The calculation unit 71 executes the oxygen supply amount monitoring program 722, thereby calculating the oxygen supply amount per unit time based on the output of the flowmeter 45. More specifically, the calculation unit 71 calculates the volume of oxygen supplied into the container 11 in each oxygen supply process, such as the oxygen supply processes P1, P2, P3, and P4, from the flow rate indicated by the output of the flowmeter 45 and the duration of each oxygen supply process. The calculation unit 71 also calculates the oxygen supply amount per unit time based on the relationship between the length of the predetermined time UT and the volume of oxygen supplied into the container 11 in the oxygen supply process occurring within the predetermined time UT.

[0073] As a specific example, assume that the volume of oxygen supplied into the container 11 in each of the oxygen supply processes P2 and P3 is 0.03 liters (l). Also, as described above, assume that the predetermined time UT is 30 seconds. Also, assume that the oxygen supply amount per unit time is expressed in liters per minute (l / m). When these conditions are met, the oxygen supply amount per unit time in the predetermined time UT, including the oxygen supply processes P2 and P3, is calculated to be 0.12 liters per minute (l / m).

[0074] In this way, the information processing unit 70, which functions as a determination unit in this embodiment, calculates the amount of oxygen supplied per unit time based on the flow rate detected by the flow meter 45, which functions as a flow rate acquisition unit in this embodiment. Note that a flow rate acquisition unit that does not use the flow meter 45 may also be employed. The mechanism of the flow rate acquisition unit that does not use the flow meter 45 will be described later with reference to FIG. 15.

[0075] In this embodiment, while the elapsed time from the start of FRC measurement is less than a predetermined time UT, the oxygen supply amount per unit time is calculated from the relationship between the elapsed time less than the predetermined time UT and the volume of oxygen supplied during that elapsed time less than the predetermined time UT. For example, when the predetermined time UT is α seconds and the elapsed time from the start of FRC measurement is β seconds, the calculation unit 71 multiplies the volume of oxygen supplied during that β seconds by (α / β) and regards this as the oxygen supply amount per unit time. As a specific numerical example, if α = 60 and β = 10, then (α / β) = 60 / 10 = 6, and the amount of oxygen supplied over 10 seconds is multiplied by 6 and regarded as the oxygen supply amount per unit time. In the following description, the term "deemed oxygen supply amount" refers to the oxygen supply amount per unit time calculated from the relationship between the elapsed time and the volume of oxygen supplied during that time.

[0076] In this manner, the information processing unit 70, which functions as a determination unit in this embodiment, calculates the average oxygen supply rate per unit time from the relationship between the elapsed time from a predetermined time point and the oxygen supply rate until a predetermined time has elapsed from the predetermined time point, and regards the calculated average as the oxygen supply rate per unit time. Note that the predetermined time point is, for example, the start time of FRC measurement, but is not limited to this. For example, it may be the time when n breaths for the respiratory reference position described below are completed. n is, for example, 5, but may also be a natural number less than or greater than 5.

[0077] In addition, in this embodiment, after the elapsed time from the start of FRC measurement becomes equal to or greater than the predetermined time UT, the oxygen supply amount per unit time is calculated based on the volume of oxygen supplied during the time period preceding the most recent timing by the predetermined time UT. For example, at timing F12, timing F11, which is the predetermined time UT prior to timing F12, is set as the start of the predetermined time UT, and timing F12 is set as the end of the predetermined time UT. Similarly, at timing F22, timing F21 is set as the start of the predetermined time UT, and timing F22 is set as the end of the predetermined time UT. At timing F32, timing F31 is set as the start of the predetermined time UT, and timing F32 is set as the end of the predetermined time UT. At timing F42, timing F41 is set as the start of the predetermined time UT, and timing F42 is set as the end of the predetermined time UT. Note that timing F21 occurs later than timing F11. Timing F31 is later than timing F21. Timing F41 is later than timing F31.

[0078] 5, the predetermined time UT starting at timing F11, timing F21, or timing F31 has in common that the oxygen supply processes occurring are oxygen supply processes P2 and P3. Therefore, the oxygen supply amount per unit time of these predetermined times UT is the same. On the other hand, the predetermined time UT starting at timing F41 has the oxygen supply processes occurring at oxygen supply processes P3 and P4. Furthermore, the oxygen supply process P4 is significantly longer than the oxygen supply processes P2 and P3. Therefore, the predetermined time UT starting at timing F41 may have a larger oxygen supply amount per unit time than the other predetermined times UT.

[0079] Next, we will explain the relationship between an abnormality in an airflow generating unit such as the fan 30 and the amount of oxygen supplied. First, we will define the normal state as a state in which the fan 30 is operating normally, and explain the normal state. Under normal conditions, human HU exhalation is guided toward the absorbent container 18 by the operation of the fan 30, passes through the absorbent container 18, and enters the container 11. This causes carbon dioxide contained in the exhalation to be absorbed by the absorbent, resulting in the reduction of the mixed gas described above. This reduction in the mixed gas can cause the peak of the downward movement of the volume position, which indicates the peak of the exhalation, to reach a position equal to or greater than the threshold value Th1. Therefore, normal operation of the fan 30 is important from the perspective of properly supplying oxygen during FRC measurement.

[0080] On the other hand, the unintentional abnormal stop of the fan 30 due to a malfunction or other reason will be defined as a "stop" and will be described below. That is, in the following description, a stop is treated as "an example of an abnormality in the airflow generating unit." When the fan 30 is stopped, the source of the airflow Ve11 that guides the exhaled breath of the human HU toward the absorbent container 18 is lost. As a result, the movement of gas accompanying the breathing of the human HU is more likely to be completed within the conduit section 20, and the carbon dioxide concentration in the conduit section 20 is more likely to increase. This is equivalent to the amount of carbon dioxide absorbed by the absorber in the absorbent container 18 being reduced when the fan 30 is stopped compared to normal. Therefore, the degree of decrease in the volume of the mixed gas in the container 11 when the fan 30 is stopped is smaller than when the fan 30 is stopped. Therefore, when the fan 30 is stopped, the frequency of the event in which the peak of the decrease in the volume position indicating the peak of exhalation reaches or exceeds the threshold value Th1 is reduced. As a result, the amount of oxygen supplied when the fan 30 is stopped is lower than when the fan 30 is stopped.

[0081] If FRC measurement continues while the fan 30 is stopped, the human HU will breathe the gas remaining in the duct 20. Therefore, the human HU will breathe gas that is relatively low in oxygen and high in carbon dioxide compared to air. This causes the human HU to feel short of breath as the FRC measurement progresses. Furthermore, the airflow Ve11 generated by the fan 30 also acts as a force to circulate the mixed gas in the container 11 through the duct 20. However, if this force is lost, the helium concentration in the container 11 will not decrease easily, and the accuracy of the FRC measurement will be impaired. Therefore, it is important for FRC measurement that the fan 30 is operating normally and that abnormal stops of the fan 30 can be detected.

[0082] Therefore, in the embodiment, a mechanism is provided that can detect abnormal stoppage of the fan 30 based on the oxygen supply amount during FRC measurement. Specifically, whether abnormal stoppage of the fan 30 has occurred is determined based on the relationship between the oxygen supply amount per unit time described above and a predetermined threshold value. The predetermined threshold value is set to a value significantly lower than the oxygen supply amount under normal conditions. The normal oxygen supply amount refers to the oxygen supply amount per unit time that is expected to occur when FRC measurement is performed while the fan 30 is operating normally.

[0083] To give a specific example, the normal oxygen supply amount in the respiratory function measuring device 1 is approximately 0.24 liters per minute (l / m). In this embodiment, for example, half of this normal oxygen supply amount is set as the predetermined threshold. That is, in this example, the predetermined threshold is 0.12 (liters per minute (l / m)). The specific value and unit of the predetermined threshold are merely examples and are not limited to these and can be changed as appropriate.

[0084] In this embodiment, when the oxygen supply amount per predetermined time UT after the start of FRC measurement falls below a predetermined threshold, it is determined that the oxygen supply amount has decreased due to an abnormal stop of the fan 30. In this embodiment, when this determination is made, an alarm is issued to notify that it has been determined that an abnormal stop of the fan 30 has occurred (for example, see FIG. 8, which will be described later).

[0085] In the embodiment, if the deemed oxygen supply amount becomes equal to or less than a predetermined threshold when the elapsed time after the start of FRC measurement is less than a predetermined time UT, it is determined that the oxygen supply amount may be reduced due to an abnormal stop of the fan 30. In the embodiment, if this determination is made, a warning is issued to notify the user that an abnormal stop of the fan 30 may have occurred (for example, see FIG. 7 described below).

[0086] The information processing unit 70 is responsible for determining whether the fan 30 has stopped abnormally based on the oxygen supply amount per unit time and issuing a warning or alert in response to the determination. Specifically, the fan abnormality detection program 723 includes parameters indicating the processing details and predetermined thresholds for determining whether the fan 30 has stopped abnormally based on the oxygen supply amount per unit time and issuing a warning or alert in response to the determination. The calculation unit 71 executes the fan abnormality detection program 723, thereby performing the processing for determining whether the fan 30 has stopped abnormally based on the oxygen supply amount per unit time and issuing a warning or alert in response to the determination. More specifically, the calculation unit 71 calculates the assumed oxygen supply amount and the oxygen supply amount per predetermined time UT, compares the calculated oxygen supply amount with a predetermined threshold, and determines whether the fan 30 has stopped abnormally. The calculation unit 71 issues a warning or alert in response to the determination.

[0087] Therefore, in this embodiment, the information processing unit 70 functions as a determination unit that determines the amount of oxygen supplied per unit time into the sealed container unit formed of the container unit 11, the piston 12, and the flexible membrane 13. The information processing unit 70 also functions as a notification unit that issues a notification in accordance with the determination result of the determination unit.

[0088] Specific examples of the above-mentioned warnings and alarms will be described below with reference to FIGS.

[0089] Fig. 6 is a schematic diagram showing an example of the display output content when FRC measurement is being performed. Fig. 7 is a schematic diagram showing an example of the display output content when a warning is issued during FRC measurement. Fig. 8 is a schematic diagram showing an example of the display output content when a warning is issued during FRC measurement. Display output content D1 shown in Fig. 6, display output content D2 shown in Fig. 7, and display output content D3 shown in Fig. 8 are display output content by a display device included in output unit 74.

[0090] The display output contents D1, D2, and D3 all include a title display section K, a volume position display section C1, and a parameter display section C3. The title display section K indicates the content of the respiratory function measurement currently being performed. The volume position display section C1 reflects the volume position after the start of FRC measurement in real time. The parameter display section C3 displays various parameters related to the respiratory function measurement currently being performed.

[0091] As the FRC measurement progresses, the display output content transitions in the order of Figure 6, Figure 7, and Figure 8. Therefore, the real-time drawing content of the volume position in the volume position display section C1 becomes gradually longer, such as the waveform WA in Figure 6, the waveform WB in Figure 7, and the waveform WC in Figure 8.

[0092] Furthermore, display output content D1, display output content D2, and display output content D3 include display content that indicates the oxygen supply amount during FRC measurement. Information display section C21 in display output content D1, information display section C22 in display output content D2, and information display section C23 in display output content D3 correspond to display content that indicates the oxygen supply amount during FRC measurement.

[0093] The display output content D1 shown in Fig. 6 shows the display output content during FRC measurement while the fan 30 has not been determined to have stopped abnormally. The information display section C21 in the display output content D1 includes display output content indicating the oxygen supply rate calculated at that time. In Figs. 6, 7, and 8, the character string "oxygen supply rate z.zz (l / m)" is shown as an example of the display output content indicating the oxygen supply rate, but the form of the display output content is merely a specific example and is not limited to this, and other forms that allow similar content to be understood may be used. For example, the oxygen supply rate may be displayed as a bar graph.

[0094] Display output content D2 shown in Fig. 7 shows the display output content during FRC measurement while a warning based on the oxygen supply rate is being issued. The information display section C22 in display output content D2 includes display output content indicating the oxygen supply rate calculated at that time and display output content as a warning to notify the user that the fan 30 may have stopped abnormally. In Fig. 7, the display output content for issuing the warning is exemplified by the character strings "Warning" and "The fan may have stopped," but the form of the display output content is merely illustrative and is not limited to this and can be changed as appropriate.

[0095] Display output content D3 shown in Fig. 8 shows display output content associated with the stop of FRC measurement due to a determination based on the oxygen supply amount that an abnormal stop of the fan 30 has occurred. The information display section C23 in display output content D3 includes display output content indicating the oxygen supply amount calculated at that time, display output content as an alarm for notifying that it has been determined that an abnormal stop of the fan 30 has occurred, and display output content notifying that FRC measurement has been stopped. In Fig. 8, the character string "ALARM" is exemplified as the display output content for the alarm, and the character string "FRC measurement has been stopped because an abnormality was detected" is exemplified as the display output content notifying that FRC measurement has been stopped, but the form of the display output content is merely a specific example and is not limited to this and can be changed as appropriate.

[0096] Furthermore, the display output content D1 and the display output content D2 include an operation acceptance section AB1. Furthermore, the display output content D3 includes an operation acceptance section AB2. The operation acceptance section AB1 functions as a button for manually stopping the FRC measurement. The operation acceptance section AB2 functions as a button for manually preparing to resume the FRC measurement. In this way, an input unit such as the operation acceptance section AB1 may be provided as a mechanism for manually stopping the FRC measurement during FRC measurement. Furthermore, an input unit such as the operation acceptance section AB2 may be provided as a mechanism for more quickly restarting the FRC measurement if the FRC measurement is automatically stopped. However, it is desirable to correct the abnormality in the fan 30 and take measures to ensure normal operation before operating the operation acceptance section AB2. The process for switching the display between the operation acceptance section AB1 and the operation acceptance section AB2 is included in, for example, the FRC measurement program 721.

[0097] 6 to 8, examples of issuing a notification such as a warning or alarm via display output have been shown, but the specific method of notification is not limited to display output. For example, notification may be issued via audio output, such as output of a warning voice or alarm voice, or multiple outputs may be issued in parallel, such as a combination of display output and audio output, or an abnormality may be indicated by a change in the color of the display output.

[0098] Furthermore, even when a warning or alarm is issued by display output, other forms may be employed. For example, a dedicated light-emitting element may be provided to indicate the presence or absence of an abnormality in the fan 30 by switching between on and off. An example of such a light-emitting element is an LED (Light Emitting Diode), but other configurations that function similarly may also be used. Furthermore, an indicator or the like may be provided to indicate the oxygen supply rate, and the oxygen supply rate indicated by the indicator may change in response to changes in the oxygen supply rate.

[0099] 9 is a flowchart showing the flow of processing related to detection of an abnormality in the fan 30 during FRC measurement performed by the respiratory function measuring device 1. After the FRC measurement is started (step S1), while a predetermined time has not elapsed (step S2; No), a deemed oxygen supply amount is calculated according to the length of time elapsed since the start of the FRC measurement (step S3). After processing in step S3, if the deemed oxygen supply amount is equal to or less than a predetermined threshold (step S4; Yes), a warning is issued to notify the user that the fan 30 may have stopped abnormally (step S5). If the deemed oxygen supply amount is not equal to or less than the predetermined threshold (step S4; No), the processing in step S5 is not performed.

[0100] After the process of step S5 or if the deemed oxygen supply amount is not equal to or less than a predetermined threshold (step S4; No), a determination is made as to whether the FRC measurement has been completed (step S6). Generally, the FRC measurement is not completed during the period in which the deemed oxygen supply amount is calculated, so the case in which the FRC measurement has not been completed (step S6; No) will be described here. If the FRC measurement has not been completed (step S6; No), the process proceeds to step S2. That is, a determination is made as to whether a predetermined time has elapsed. Here, if the predetermined time has elapsed (step S2; Yes), the oxygen supply amount per unit time is calculated based on the amount of oxygen supplied during the predetermined time period, starting from a time point prior to the most recent time by a predetermined time and ending with the most recent time (step S7). After the process of step S7, if the oxygen supply amount per unit time is equal to or less than a predetermined threshold (step S8; Yes), an alarm is issued to notify that the fan 30 has stopped abnormally, and the FRC measurement is stopped (step S9). When the process of step S9 is performed, the FRC measurement is stopped, and the process of detecting an abnormality in the fan 30 during the FRC measurement is terminated. Note that if the oxygen supply amount per unit time is not equal to or less than the predetermined threshold value (step S8; No), the process of step S9 is not performed.

[0101] If the amount of oxygen supplied per unit time is not equal to or less than the predetermined threshold in the process of step S8 (step S8; No), the process proceeds to a determination of whether the FRC measurement is complete (step S6). If the FRC measurement is not complete (step S6; No), the process proceeds to step S2. If the FRC measurement is complete (step S6; Yes), the process related to detecting an abnormality in the fan 30 during the FRC measurement ends.

[0102] 6 to 9 and the description below with reference to Figures 10 and 11, the oxygen supply amount per unit time and the assumed oxygen supply amount will be zero until the oxygen supply process has been performed at least once, and a warning or alarm will always be issued. Therefore, as an exception, it may be possible not to issue a warning or alarm until the timing at which the first oxygen supply process is normally expected to be completed after the start of FRC measurement.

[0103] Specifically, in FRC measurement, the first n breaths taken by the human HU after the start of measurement are set as the respiratory reference position. Note that one breath is a continuous process of one inhalation and one exhalation. Normally, it is assumed that the initial oxygen supply process is completed by the time the n breaths for the respiratory reference position are completed. Therefore, as an exception, a notification such as a warning or alarm may not be issued until the n breaths for the respiratory reference position are completed. When the time when the n breaths for the respiratory reference position are completed is set as the predetermined time, the predetermined time is determined accordingly.

[0104] As described with reference to Figures 6 to 9, in the embodiment, a warning is issued when the oxygen supply amount per unit time is equal to or less than a predetermined threshold. Furthermore, as described with reference to Figures 8 and 9, in the embodiment, when the oxygen supply amount per unit time becomes equal to or less than a predetermined threshold after a predetermined time or more has elapsed from a predetermined point in time, a warning indicating that FRC measurement as respiratory function measurement using the respiratory function measuring device 1 will be stopped is issued as a warning corresponding to an abnormality in the fan 30, which functions as an airflow generating unit in the embodiment. Furthermore, as described with reference to Figures 7 and 12, in the embodiment, when the oxygen supply amount per unit time from a predetermined point in time until a predetermined time has elapsed is equal to or less than a predetermined threshold, a warning indicating an abnormality in the fan 30, which functions as an airflow generating unit in the embodiment, is issued.

[0105] As described above, the respiratory function measuring device 1 includes a sealed container, two tubes, a branching tube, an airflow generating unit, an absorbent, an information output unit, an oxygen supply unit, a determination unit, and a notification unit. This allows for determination of whether the airflow generated by the airflow generating unit is normal based on the oxygen supply amount corresponding to the absorption of carbon dioxide by the absorbent during respiratory function measurements such as FRC measurements. That is, when the airflow generated by the airflow generating unit is no longer normal, it can be inferred that the absorption of carbon dioxide by the absorbent is hindered by the oxygen supply amount being lower than normal. A notification is then issued based on the determination result of the determination unit, allowing for appropriate action to be taken according to the notification content. For example, when a notification is issued regarding an abnormality in the airflow generating unit, the operator of the respiratory function measuring device 1 can temporarily suspend respiratory function measurement and then perform repairs or other work to normalize the function of the airflow generating unit. Therefore, according to the embodiment, it is possible to respond to an abnormal stoppage of the airflow generating unit.

[0106] Furthermore, when the oxygen supply amount per unit time is equal to or less than a predetermined threshold, the notification unit issues a notification, thereby enabling notification to be issued based on a clear criterion, namely, the relationship between the oxygen supply amount per unit time and the predetermined threshold.

[0107] Furthermore, if the oxygen supply rate per unit time falls below a predetermined threshold after a predetermined time has elapsed since a predetermined point in time, the notification unit issues an alarm according to an abnormality in the airflow generating unit, thereby preventing subjects from experiencing breathing difficulties during respiratory function measurements such as FRC measurements.

[0108] Furthermore, if the oxygen supply per unit time from a predetermined point until a predetermined time has elapsed is equal to or less than a predetermined threshold, the notification unit issues a warning indicating an abnormality in the oxygen supply, which makes it easier to prevent subjects undergoing respiratory function measurements such as FRC measurement from experiencing breathing difficulties.

[0109] Furthermore, the determination unit calculates the average oxygen supply amount per unit time from the relationship between the elapsed time from the predetermined time point and the oxygen supply amount until the predetermined time has elapsed, and regards the calculated average as the oxygen supply amount per unit time. This makes it possible to calculate a value that can be regarded as the oxygen supply amount per unit time even before the predetermined time has elapsed. Therefore, it is possible to determine the oxygen supply amount supplied into the sealed container and to issue a notification based on the determination result at an earlier point in time.

[0110] The oxygen supply unit also includes a solenoid valve 48 and a flow meter 45. The determination unit calculates the amount of oxygen supplied per unit time based on the flow rate detected by the flow meter 45. This makes it possible to more accurately obtain information indicating the amount of oxygen supplied by the oxygen supply process performed by the respiratory function measuring device 1.

[0111] It also has a helium supply unit that supplies helium into the sealed container, making it easier to perform respiratory function measurements that use helium, such as FRC measurements.

[0112] Also, a mouthpiece 24 is provided that is detachable from the mouthpiece connector 23. This makes it easier to apply a clean mouthpiece 24 to each subject for respiratory function measurement such as FRC measurement.

[0113] The above describes the determination of abnormal stoppage of the fan 30 based on the amount of oxygen supplied per unit time. However, abnormalities in the airflow generation unit are not limited to stoppage, i.e., abnormal stoppage of the fan 30. For example, if the fan 30 is able to rotate at a speed significantly lower than the speed per unit time intended at the time of design, an event substantially similar to that of a stopped state may occur, although not as significant as when the fan 30 is stopped. Therefore, the above-mentioned expressions "stoppage of the fan 30" and similar expressions may be replaced with "a decrease in the number of rotations per unit time of the fan 30."

[0114] Furthermore, the determination made by the determination unit based on the oxygen supply amount and the processing performed in response to the determination result are not limited to those described above. For example, the determination unit may make a determination based on the relationship between the time elapsed since a predetermined time point and the oxygen supply amount from the predetermined time point, and the notification unit may issue a notification when it is determined that the oxygen supply amount is insufficient for the elapsed time.

[0115] Specifically, the calculation unit 71 may calculate the deemed oxygen supply amount described above regardless of whether a predetermined time has elapsed since a predetermined point in time. As a specific numerical example, if α=60 and β=120, then (α / β)=60 / 120=0.5, and therefore the amount of oxygen supplied over 120 seconds is multiplied by 0.5 to be regarded as the oxygen supply amount per unit time. When the deemed oxygen supply amount calculated in this way falls below the predetermined threshold value described above, regardless of the elapse of a predetermined time, it may be determined that the oxygen supply amount is decreasing.

[0116] Furthermore, the content of the notification when it is determined that the oxygen supply rate is low is not limited to an abnormal stop of the fan 30. For example, a shortage of oxygen supply rate can also occur due to deterioration of the absorbent. Therefore, for example, the warning display output on the information display unit C22 described with reference to FIG. 7 may be changed from "The fan may have stopped" to "An abnormality may have occurred that is causing a shortage of oxygen supply rate."

[0117] In the description of step S9 with reference to FIG. 8 and FIG. 9, the FRC measurement is stopped when the oxygen supply per unit time falls below a threshold after a predetermined time has elapsed from a predetermined point in time. However, stopping the FRC measurement is not essential. Specifically, an alarm indicating an abnormality in the oxygen supply may be issued. In this case, for example, the alarm display output on the information display unit C23 described with reference to FIG. 8 may be changed from "FRC measurement has been stopped because an abnormality has been detected" to "An abnormality in the oxygen supply has been detected." In this case, the alarm may be issued as information to help the operator of the respiratory function measuring device 1 determine whether to continue or stop the FRC measurement while checking the subject's condition.

[0118] Alternatively, the total oxygen supply amount during FRC measurement may be notified after completion of the FRC measurement. In this case, the calculation unit 71 sums up the oxygen supply amounts due to each of the oxygen supply processes (e.g., P1, P2, P3, and P4 shown in FIG. 5) that occurred during the FRC measurement. The oxygen supply amount indicated by the sum is displayed as the total oxygen supply amount during the FRC measurement in the information display unit C21 (see FIG. 6). Note that the specific manner in which the total oxygen supply amount during FRC measurement is not limited to this and can be changed as appropriate.

[0119] 10 is a flowchart showing the process flow for detecting a shortage of oxygen supply in FRC measurement when a determination is made based on the relationship between the elapsed time from a predetermined time point and the oxygen supply amount from the predetermined time point. In the explanation with reference to FIG. 10, the same steps as those explained with reference to FIG. 9 are assigned the same step numbers, and explanations thereof will be omitted.

[0120] After the process of step S1, the assumed oxygen supply amount is calculated according to the length of time elapsed since the start of FRC measurement (step S21). The process of step S21 is the same as the process of step S3, except that the assumed oxygen supply amount is calculated regardless of whether a predetermined time has elapsed since a predetermined point in time.

[0121] If the deemed oxygen supply amount calculated in the processing of step S21 is equal to or less than a predetermined threshold (step S22; Yes), it is determined whether a predetermined time has passed since a predetermined time point (step S23). If the predetermined time has not passed since the predetermined time point (step S23; No), a warning is issued to notify the user that the oxygen supply amount may be insufficient (step S24). If the predetermined time has passed since the predetermined time point (step S23; Yes), an alarm is issued to notify the user that the oxygen supply amount is insufficient (step S25).

[0122] After the process of step S24, after the process of step S25, or if the deemed oxygen supply amount calculated in the process of step S21 is not equal to or less than a predetermined threshold (step S22; No), the process proceeds to step S6. If the FRC measurement is not completed (step S6; No), the process proceeds to step S21. If the FRC measurement is completed (step S6; Yes), the total oxygen supply amount during the FRC measurement is notified (step S26), and the process related to detecting a shortage of oxygen supply amount in the FRC measurement ends.

[0123] The above has described, with reference to FIG. 10, a case in which a judgment is made based on the relationship between the time elapsed from a predetermined time point and the amount of oxygen supplied from that predetermined time point. However, the processing flow described with reference to FIG. 9 may further incorporate a judgment based on the relationship between the time elapsed from a predetermined time point and the amount of oxygen supplied from that predetermined time point.

[0124] Fig. 11 is a flowchart showing the process flow for detecting a shortage of oxygen supply amount in FRC measurement when a determination based on the relationship between the elapsed time from a predetermined time point and the oxygen supply amount from the predetermined time point is further incorporated into the process flow described with reference to Fig. 9. In the description with reference to Fig. 11, the same steps as those described with reference to Figs. 9 and 10 are denoted by the same step numbers, and their description will be omitted.

[0125] The processing flow shown in FIG. 11 includes the processing of step S1, step S2, step S3, step S4, step S7, and step S8 in the processing flow described with reference to FIG.

[0126] In the process flow shown in Fig. 11, if the deemed oxygen supply amount is equal to or less than a predetermined threshold in the process of step S4 (step S4; Yes), the process of step S24 described with reference to Fig. 10 is performed (step S24). Note that if the deemed oxygen supply amount is not equal to or less than the predetermined threshold (step S4; No), the process of step S24 is not performed.

[0127] 11, if the oxygen supply amount per unit time is equal to or less than a predetermined threshold in the process of step S8 (step S8; Yes), the process of step S25 described with reference to FIG. 10 is performed (step S25). If the oxygen supply amount per unit time is not equal to or less than the predetermined threshold (step S8; No), a deemed oxygen supply amount is calculated according to the length of time elapsed since the start of FRC measurement (step S31). The process of step S31 is the same as the process of step S21 described with reference to FIG. 10, except that it does not include the period before the predetermined time has elapsed from the predetermined point in time.

[0128] If the deemed oxygen supply amount calculated in the process of step S31 is equal to or less than the predetermined threshold value (step S32; Yes), the process of step S25 is carried out.

[0129] After the processing of step S24 or step S25, if the deemed oxygen supply amount calculated in the processing of step S31 is not equal to or less than a predetermined threshold (step S32; No), or if the deemed oxygen supply amount in the processing of step S4 is not equal to or less than a predetermined threshold (step S4; No), the processing proceeds to step S6. If the FRC measurement is not completed (step S6; No), the processing proceeds to step S2. If the FRC measurement is completed (step S6; Yes), the processing of step S26 described with reference to FIG. 10 is performed, and the processing related to detecting a shortage of oxygen supply amount in the FRC measurement is completed.

[0130] The notification regarding "insufficient oxygen supply amount" in the process described with reference to FIG. 10 and the process described with reference to FIG. 11 may be a notification regarding "abnormal stop of the fan."

[0131] The method of determining whether there is a shortage of oxygen supply and whether the fan 30 has stopped abnormally is not limited to the method based on the oxygen supply amount per unit time.

[0132] For example, an abnormal stop of the fan 30 may be detected based on the rate of increase in the helium concentration detected by the helium concentration sensor 61 when helium is supplied from the helium cylinder B1 into the container 11 via the supply unit 40 before the FRC measurement is performed.

[0133] FIG. 12 is a graph showing the rate of increase in helium concentration detected by helium concentration sensor 61 when helium is supplied from helium cylinder B1 into container 11 via supply unit 40 before FRC measurement. The vertical axis of the graph shown in FIG. 12 represents the level of helium concentration detected by helium concentration sensor 61. The horizontal axis of the graph represents the elapsed time from the start of helium supply into container 11. For example, assume that the rate of increase in helium concentration under normal conditions is line L4. Under normal conditions, gas circulates between container 11 and conduit 20 due to airflows Ve11 and Ve12. Therefore, the rate of increase in helium concentration in container 11 is slowed by the amount of helium moving into conduit 20.

[0134] On the other hand, when the system is stopped, the airflows Ve11 and Ve12 are not generated. That is, no active force is generated to circulate the gas between the inside of the container 11 and the inside of the duct 20. This makes it difficult for helium to move into the duct 20, and the rate at which the helium concentration in the container 11 increases is higher than in normal operation. Therefore, the rate at which the helium concentration increases when the system is stopped is, for example, as shown by line L5.

[0135] As shown by comparing lines L4 and L5, the rate at which the helium concentration increases during shutdown is faster than during normal operation. Therefore, by being able to detect the rate at which the helium concentration increases, which does not occur during normal operation, it is possible to determine whether the fan 30 has abnormally stopped before FRC measurement. Specifically, before FRC measurement, data is measured in advance for the helium concentration at a certain point in time (e.g., timing t3 shown in FIG. 12 ) after helium supply from the helium cylinder B1 to the container 11 via the supply unit 40 begins. The data is then used to measure both the helium concentration during normal operation and when the fan 30 is intentionally stopped to simulate a situation similar to that during shutdown. Based on this data, a helium threshold value is set in advance that cannot be reached during normal operation and is expected to be exceeded during shutdown. In FIG. 12 , a threshold value Th2 is shown as the helium threshold value. After starting the supply of helium from helium cylinder B1 into container 11 via supply unit 40 before FRC measurement, if the helium concentration at that point in time is equal to or greater than the helium threshold, calculation unit 71 can determine that an abnormal stop of fan 30 or a shortage of oxygen supply has occurred due to a reason other than the abnormal stop of fan 30.

[0136] Also, a dedicated configuration may be provided for detecting the operating state of the fan 30. A case where such a dedicated configuration is provided will be described with reference to FIG.

[0137] Fig. 13 is a block diagram showing a respiratory function measuring device 1A including a fan monitoring unit 31. As shown in Fig. 13, the respiratory function measuring device 1A includes a fan monitoring unit 31 in addition to the configuration of the respiratory function measuring device 1 described with reference to Fig. 2. The fan monitoring unit 31 monitors the operation of the fan 30. Specifically, the fan monitoring unit 31 is, for example, a pulse sensor that can monitor the operation of the fan 30 by detecting a periodic pulse signal output in accordance with the rotation of the fan 30.

[0138] The fan abnormality detection program 723A in the respiratory function measuring device 1A includes processing corresponding to the function of determining whether the fan 30 has stopped abnormally based on a pulse signal detected by the fan monitoring unit 31. The calculation unit 71 that executes the fan abnormality detection program 723A determines that the fan 30 has stopped abnormally when the fan monitoring unit 31 cannot detect a pulse signal even though the fan 30 should be operating in conjunction with the operation of the respiratory function measuring device 1A.

[0139] The fan monitoring unit 31 is not limited to a pulse sensor. For example, a photocoupler or the like that can physically detect the operation of the fan 30 may be used, a pressure sensor that detects the pressure difference between the intake side and the delivery side of the fan 30, or a rotation detection sensor using another method may be used.

[0140] Furthermore, a configuration may be provided in which, even when the fan 30 is stopped, breathing causes gas to circulate between the inside of the duct section 20 and the inside of the container section 11. A case in which such a configuration is provided will be described with reference to FIG.

[0141] 14 is a schematic diagram showing the main configuration of a respiratory function measuring device 1B provided with a one-way valve 25. Respiratory function measuring device 1B includes a one-way valve 25 in addition to the configuration of respiratory function measuring device 1 described with reference to FIG. 1. One-way valve 25 is provided in conduit portion 20 and regulates the movement direction of gas in one direction. Specifically, one-way valve 25 does not substantially impede the flow of gas in the direction from mouthpiece connecting portion 23 to container portion 11 via absorbent container 18, but suppresses the flow of gas in the direction from mouthpiece connecting portion 23 to container portion 11 without passing through absorbent container 18.

[0142] 14, one-way valves 25 are provided in each of the first tube section 21 and the second tube section 22, with the mouthpiece connection section 23 sandwiched between them. The one-way valve 25 provided in the first tube section 21 regulates the direction of gas movement from the first tube section 21 toward the mouthpiece connection section 23. The one-way valve 25 provided in the second tube section 22 regulates the direction of gas movement from the mouthpiece connection section 23 toward the absorbent container 18.

[0143] By providing the one-way valve 25, the movement of gas in the conduit section 20 associated with breathing by the human HU is restricted to the direction from the mouthpiece connection section 23 toward the absorbent container 18, and is prevented from moving in the opposite direction. As a result, even if the fan 30 stops abnormally, the exhaled gas can be moved from the conduit section 20 toward the absorbent container 18 and passed through the absorbent container 18. Furthermore, the pressure difference associated with this movement of exhaled gas can attract the gas in the container section 11 toward the first conduit section 21. Therefore, even if the fan 30 stops abnormally, the one-way valve 25 makes it possible to circulate the mixed gas between the conduit section 20 and the container section 11 and to generate a gas movement that passes the exhaled gas through the absorbent container 18.

[0144] Furthermore, the flow rate obtaining unit does not need to use the flow meter 45. In this case, the flow meter 45 is omitted. A configuration in which the flow meter 45 is omitted will be described with reference to FIG.

[0145] 15 is a block diagram showing a configuration example in which an oxygen supply amount monitoring program 722A is employed that does not use a flow meter 45. The calculation unit 71 that executes the oxygen supply amount monitoring program 722A calculates the volume of oxygen supplied into the container 11 in each oxygen supply process from the "oxygen supply amount per unit time" measured in advance and the duration of each oxygen supply process such as oxygen supply processes P1, P2, P3, and P4 (see FIG. 5). Here, the "oxygen supply amount per hour" is measured in advance, and information indicating the "oxygen supply amount per hour" is included in the oxygen supply amount monitoring program 722A.

[0146] Specifically, the "oxygen supply amount per hour" is predominantly determined by the oxygen supply pressure from an oxygen supply source such as oxygen cylinder B2 and the specific structure of the gas flow path (supply unit 40, connecting pipe 50) connecting the oxygen supply source and the sealed container, in particular the flow rate characteristics of solenoid valve 48, and the air pressure inside the sealed container hardly contributes to determining the "oxygen supply amount per hour." Therefore, by measuring in advance the "oxygen supply amount per hour" when solenoid valve 48 is open and including information indicating the "oxygen supply amount per hour" corresponding to the measurement result in oxygen supply amount monitoring program 722A, the volume of oxygen supplied can be calculated without using flow meter 45.

[0147] Although the configuration of FIG. 15 includes the fan monitoring unit 31 described with reference to FIG. 13, the fan monitoring unit 31 may be omitted.

[0148] 1 to 15 can be modified as appropriate. An example in which such modifications are reflected will be described with reference to FIG.

[0149] Figure 16 is a schematic diagram showing an example in which some of the various features described with reference to Figures 1 to 15 have been modified. For example, the airflow generating unit (e.g., fan 30) provided on the second pipe section 22 side in Figure 1 may be provided on the first pipe section 21 side. In Figure 16, the airflow generating unit provided on the first pipe section 21 side is shown as fan 30A.

[0150] Furthermore, the direction of airflow caused by breathing is not limited to the directions indicated by the airflows Ve11 and Ve12 shown in Fig. 1. Fig. 16 shows airflows Ve21 and Ve22 that are directed in the opposite direction to the airflows Ve11 and Ve12 shown in Fig. 1.

[0151] When a one-way valve such as one-way valve 25 is provided, the restriction of airflow by such one-way valve corresponds to the direction of airflow associated with breathing, such as airflow Ve11, Ve12 or airflow Ve21, Ve22. In Fig. 16, one-way valve 25A is provided that restricts airflow in the opposite direction to one-way valve 25 described with reference to Fig. 14.

[0152] In addition, in Figure 16, the direction of the airflow generated by fan 30A corresponds to airflows Ve21 and Ve22, but in the configuration in which airflows Ve11 and Ve12 shown in Figure 1 are generated, the direction of the airflow generated by fan 30A is opposite to the direction shown in Figure 16.

[0153] Furthermore, at least one of the helium and oxygen supply sources does not have to be a cylinder. In Fig. 16, pipe 43 is connected to helium supply pipe PL11, and pipe 44 is connected to oxygen supply pipe PL21. Note that joint J11 between pipe 43 and helium supply pipe PL11 and joint J21 between pipe 44 and oxygen supply pipe PL21 are joints of the pipes.

[0154] 15, the flow meter 45 between the pipe 44 and the pipe 46 can be omitted. In FIG. 16, an example of a configuration in which the flow meter 45 is omitted is shown.

[0155] Note that the combination of the configurations shown in Fig. 1 and the combination of the configurations shown in Fig. 16 are not mutually exclusive. Some of the details described with reference to Fig. 16 may be reflected in the configuration shown in Fig. 1. For example, the airflows Ve11 and Ve12 in Fig. 1 may be replaced with airflows Ve21 and Ve22, with the rest remaining the same as Fig. 1. Furthermore, at least one of the helium cylinder B1 and the oxygen cylinder B2 in Fig. 1 may be replaced with a helium supply pipe PL11 and an oxygen supply pipe PL21, with the rest remaining the same as Fig. 1. In a similar way, some or all of the details described with reference to Figs. 12 to 16 may be reflected in Fig. 1.

[0156] In the above description, 0.24 liters per minute (l / m) was given as a specific example of the normal oxygen supply rate in the respiratory function measuring device 1, but the normal oxygen supply rate is not limited to this. For example, since it is known that human oxygen consumption correlates with the age and sex of the subject, the normal oxygen supply rate may be determined according to the age and sex of the subject.

[0157] FIG. 17 is a graph showing hourly calorie consumption and hourly oxygen intake according to a combination of human age and gender. As shown in FIG. 17, the calorie consumption and oxygen intake per hour vary depending on the age of the individual. Furthermore, the calorie consumption and oxygen intake per hour vary between male and female individuals, even if they are the same age. In consideration of such trends in hourly oxygen intake, the normal oxygen supply volume of the respiratory function measuring device 1 may be determined according to the combination of the subject's age and gender. Specifically, data indicating the normal oxygen supply volume for each combination of the subject's age and gender may be stored in the storage unit 72, and the calculation unit 71 may determine the normal oxygen supply volume by referring to the data in response to execution of the FRC measurement program 721. When the normal oxygen supply volume is determined in this manner, information indicating the subject's age and gender is input via the input unit 73 before FRC measurement is performed.

[0158] More precisely, since it is known that a person's oxygen intake, i.e., oxygen consumption, tends to depend on the subject's body surface area, height and weight, which have a relatively strong correlation with body surface area, may be included in the parameters for determining oxygen consumption.

[0159] It is desirable that the volume of the space between the two one-way valves 25 arranged in the first tube section 21 and the second tube section 22 across the mouthpiece connection section 23 be less than the volume of one exhalation produced by a human HU breathing. This makes it easier to force a gas flow through the one-way valves 25 as exhalation occurs.

[0160] The respiratory function measurement by the above-described respiratory function measuring device 1 is not limited to FRC measurement. For example, a threshold-based judgment and a notification according to the judgment result may be performed based on other respiratory function measurements that involve oxygen supply.

[0161] In addition, in the embodiment, the calculation unit 71 functions as a control unit for the determination unit and the notification-related processing by so-called software processing, but dedicated hardware corresponding to such functions may be provided in the respiratory function measuring device. [Explanation of symbols]

[0162] 1. Respiratory function measuring device 11 Container section 12 pistons 13 Flexible membrane 18 Absorbent container 21 First Pipe Section 22 Second Pipe Section 23 Mouthpiece connection part 30 fans 40 Supply section 48 Solenoid valve 50 Connecting pipe 70 Information Processing Department 71 Arithmetic section 72 Memory section 74 Output section B1 Helium Cylinder B2 Oxygen Cylinder

Claims

1. a sealed container portion having a container-shaped fixed portion and a movable portion that cooperates with the fixed portion to seal a gas inside and is provided so as to be movable relative to the fixed portion, wherein the movable portion moves relative to the fixed portion in response to an increase or decrease in the volume of the gas sealed inside; two pipe portions connected to the fixed portion to form a gas flow path leading to the inside of the sealed container portion; a branch pipe portion interposed between the mouth of the subject and the two pipe portions during respiratory function measurement, and adapted to cause changes in air pressure caused by mouth breathing of the subject into the two pipe portions; an airflow generating unit provided in the gas flow path to generate an airflow in the two pipe units and the sealed container unit; an absorbent that is provided within an influence range of the airflow and on the sealed container side of one of the two pipeline sections and absorbs carbon dioxide; an information output unit that generates an output indicating information corresponding to the volume of gas in the sealed container; an oxygen supply unit that supplies oxygen into the sealed container unit in accordance with the volume of carbon dioxide absorbed by the absorbent; a determination unit that determines the amount of oxygen supplied into the sealed container; a notification unit that issues a notification in accordance with the determination result of the determination unit; Equipped with The alternating occurrence of exhalation and inhalation due to the mouth breathing increases or decreases the volume of gas in the sealed container, causing a change in the volume, which is the output, so that the volume decreases with exhalation and increases with inhalation, The volume increases in response to the amount of carbon dioxide absorbed by the absorbent, Oxygen is supplied from the point in time when the peak of the decrease in the volume corresponding to the peak of expiration becomes equal to or greater than a first threshold value, As oxygen is delivered, the volume drops, The supply of oxygen is continued until the peak of the volume decline corresponding to the peak of expiration occurring after the start of the most recent supply of oxygen is below the first threshold. Respiratory function measuring device.

2. When the oxygen supply amount per unit time is equal to or less than a second threshold value, the notification unit issues a notification. The respiratory function measuring device according to claim 1 .

3. A sealed container part having a container-shaped fixed part and a movable part which cooperates with the fixed part to seal gas inside and is movable relative to the fixed part, wherein the movable part moves relative to the fixed part in response to an increase or decrease in the volume of the gas sealed inside; two pipe portions connected to the fixed portion to form a gas flow path leading to the inside of the sealed container portion; a branch pipe portion interposed between the mouth of the subject and the two pipe portions during respiratory function measurement, and adapted to cause changes in air pressure caused by mouth breathing of the subject into the two pipe portions; an airflow generating unit provided in the gas flow path to generate an airflow in the two pipe units and the sealed container unit; an absorbent that is provided within an influence range of the airflow and on the sealed container side of one of the two pipeline sections and absorbs carbon dioxide; an information output unit that generates an output indicating information corresponding to the volume of gas in the sealed container; an oxygen supply unit that supplies oxygen into the sealed container unit in accordance with the volume of carbon dioxide absorbed by the absorbent; a determination unit that determines the amount of oxygen supplied into the sealed container; a notification unit that issues a notification in accordance with the determination result of the determination unit; Equipped with When the amount of oxygen supplied per unit time becomes equal to or less than a threshold value after a predetermined time or more has elapsed from a predetermined point in time, the notification unit issues an alarm corresponding to an abnormality in the airflow generation unit. Respiratory function measuring device.

4. When the amount of oxygen supplied per unit time from the predetermined time point until the predetermined time has elapsed is equal to or less than the threshold value, the notification unit issues a warning indicating an abnormality in the airflow generation unit. The respiratory function measuring device according to claim 3 .

5. the determination unit calculates an average value of the oxygen supply amount per unit time from the relationship between the elapsed time from the predetermined time point and the oxygen supply amount until the predetermined time has elapsed from the predetermined time point, and regards the calculated average value as the oxygen supply amount per unit time; The respiratory function measuring device according to claim 4.

6. The determination unit makes a determination based on a relationship between an elapsed time from a predetermined time point and an oxygen supply amount from the predetermined time point, and the notification unit makes a notification when it is determined that the oxygen supply amount is insufficient for the elapsed time. The respiratory function measuring device according to claim 1 .

7. The oxygen supply unit an electromagnetic valve provided in a gas flow path connecting an oxygen cylinder and the sealed container portion so as to be able to open and close the flow path; a flow rate acquiring unit that acquires information indicating the flow rate of gas flowing through a gas flow path that connects an oxygen cylinder and the sealed container unit, the determination unit calculates an oxygen supply amount per unit time based on the flow rate indicated by the information acquired by the flow rate acquisition unit. The respiratory function measuring device according to claim 1 .

8. a helium supply unit that supplies helium into the sealed container unit, The respiratory function measuring device according to claim 1 .

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