JP6860160B2 - Pulmonary function test device - Google Patents

Description

The present invention relates to a respiratory function test device for obtaining a diagnostic index for respiratory diseases.

Chronic Obstructive Pulmonary Disease (hereinafter referred to as COPD) is known as one of the respiratory diseases. Forced vital capacity (hereinafter referred to as FVC) was used as a diagnostic index for COPD. However, the effort of the subject is required when using FVC. On the other hand, the NEP (Negative Expiratory Pressure) method is described in Non-Patent Document 1 and Non-Patent Document 2 as a method that does not require the effort of the subject. The NEP method is a method for determining the presence or absence of exhalation flow rate limitation based on the flow volume curve when exhalation is assisted.

"Detertion of Expiratory Flow Limitation during Mechanical Ventilation": P Valta, C Corbeil, A Lavoie, R Campodonico, N Koulouris, M Chasse, J Braidy, J Milic-Emili, American Journal of Respiratory and Critical Care Medicine, Vol.150, 1994, p.1311-1317 "A simple method to detect expiratory flow limitation during spontaneous breathing": NG Koulouris, P Valta, A Lavoie, C Corbeil, M Chasse, J Braidy, J Milic-Emili, European Respiratory Journal, Feb 1995, 8 (2), p .306-313

When the NEP method was used, the exhalation was sometimes disturbed by the reflexes of the subject when the exhalation was assisted. The data when the exhalation is disturbed cannot be used for the evaluation of COPD.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a respiratory function test device that facilitates acquisition of data that can be used as a diagnostic index.

In order to achieve the above object, the respiratory function test apparatus according to the present invention includes a branch pipe connected to at least the mouth of a subject, a first blower for discharging air inside the branch pipe, and the inside of the branch pipe. A second blower that supplies air to the branch pipe, a flow sensor that detects the flow rate of gas flowing through the branch pipe, a pressure sensor that detects the pressure inside the branch pipe, the first blower, and the second blower. The control device includes a flow sensor and a control device electrically connected to the pressure sensor, and the control device pressurizes the branch pipe and calculates a reference ventilation volume of the subject during at least a part of the intake period. Then, after calculating the reference ventilation volume, the control device pressurizes the branch pipe during at least a part of the intake period, and the ratio of the expiratory volume to the reference ventilation volume reaches a predetermined value. Depressurize the branch pipe.

As a result, the bifurcation tube is pressurized during the inspiratory period, which makes it easier for the subject's breathing to stabilize. As a result, the accuracy of the calculated reference ventilation volume is improved. By decompressing the branch pipe when the ratio of the expiratory volume to the reference ventilation volume reaches a predetermined value, bimodal peaks are less likely to occur in the flow volume curve. Therefore, the respiratory function test device facilitates the acquisition of data that can be used as a diagnostic index.

As a desirable embodiment of the respiratory function test device, it is desirable that the control device stops the decompression of the branch pipe when the expiratory volume becomes equal to the reference ventilation volume.

As a result, the subject is more likely to take the next breath, and the breathing is less likely to be disturbed. Pulmonary function testing equipment facilitates continuous measurements to obtain multiple flow volume curves.

A preferred embodiment of the respiratory function test device is a main tube connected to at least the mouth of the subject, a first auxiliary tube having an open opening and connected to the main tube, and a second auxiliary tube connected to the first auxiliary tube. The branch pipe provided, the first valve body provided in the first auxiliary pipe, the second valve body provided in the second auxiliary pipe, and the flow between the second auxiliary pipe and the main pipe are blocked. The flow between the first actuator that moves the first valve body to the open position and the closed position that blocks the flow between the opening and the main pipe, and the flow between the second blower and the first auxiliary pipe. The control device includes a depressurizing position for shutting off and a second actuator for moving the second valve body to a pressurizing position for blocking the flow between the first blower and the first auxiliary pipe. , It is desirable to be electrically connected to the first actuator and the second actuator.

If there is no first valve body and second valve body, it takes time to switch between pressurization and depressurization of the branch pipe. Therefore, the timing of switching between pressurization and depressurization of the branch pipe tends to be delayed from the ideal timing. Respiratory resistance increases because the branch tube is likely to be pressurized during the expiratory period or the branch tube is decompressed during the inspiratory period. In addition, the amount of air short-circuited between the first blower and the second blower increases. In contrast to such a problem, in the present embodiment, by controlling the positions of the first valve body and the second valve body, switching between pressurization and depressurization of the branch pipe becomes faster.

Further, as a second aspect of the present invention, the respiratory function test device includes a main pipe connected to at least the mouth of a subject, a first auxiliary pipe having an open opening and connected to the main pipe, and the first auxiliary pipe. A branch pipe provided with a second auxiliary pipe connected to the second auxiliary pipe, a first blower for discharging the air inside the second auxiliary pipe, a second blower for supplying air to the inside of the second auxiliary pipe, and the first auxiliary. An open position that blocks the flow between the first valve body provided in the pipe, the second valve body provided in the second auxiliary pipe, the second auxiliary pipe and the main pipe, and the opening and the main pipe. A first actuator that moves the first valve body to a closed position that blocks the flow between the two, a depressurized position that blocks the flow between the second blower and the first auxiliary pipe, and the first. A second actuator that moves the second valve body to a pressurizing position that blocks the flow between the blower and the first auxiliary pipe, a flow sensor that detects the flow rate of gas flowing in the branch pipe, and a flow sensor. A pressure sensor that detects the pressure in the branch pipe, and a control device that is electrically connected to the first blower, the second blower, the first actuator, the second actuator, the flow sensor, and the pressure sensor. The second blower is driven, the first valve body is in the closed position, the second valve body is in the pressurizing position, and the exhalation is provided. In a part of the period including the start of exhalation, the first valve body is in the open position, and in the other period of the exhalation period, the first blower is driven and the first valve body is moved. It is in the closed position, and the second valve body is in the depressurized position.

As a result, inspiration is assisted and breathing is likely to be stable. Further, since natural respiration is performed from the start of exhalation to the decompression of the branch tube, the exhalation is less likely to be disturbed by the decompression. Therefore, bimodal peaks are less likely to occur in the flow volume curve. Therefore, the respiratory function test device facilitates the acquisition of data that can be used as a diagnostic index.

According to the present invention, it is possible to provide a respiratory function test device that facilitates acquisition of data that can be used as a diagnostic index.

FIG. 1 is a schematic view of a respiratory function test device according to the present embodiment. FIG. 2 is a block diagram of the control device according to the present embodiment. FIG. 3 is a flowchart showing a process performed by the control device according to the present embodiment. FIG. 4 is a schematic view showing the arrangement of the first valve body and the second valve body during the intake period. FIG. 5 is a graph showing the transition of the integrated flow rate and the pressure applied to the branch pipe. FIG. 6 is a schematic view showing the arrangement of the first valve body and the second valve body during the expiratory period. FIG. 7 is a graph for explaining a method of calculating the reference ventilation volume. FIG. 8 is a schematic view showing the arrangement of the first valve body and the second valve body after the intake air volume reaches the reference ventilation volume. FIG. 9 is a schematic view showing the arrangement of the first valve body and the second valve body when the ratio of the expiratory volume to the reference ventilation volume becomes a predetermined value or more. FIG. 10 is a graph showing the transition of the integrated flow rate and the pressure reduced from the branch pipe. FIG. 11 is a graph showing an example of the flow volume curve in the present embodiment. FIG. 12 is a graph showing the transition of the integrated flow rate and the pressure applied to the branch pipe in the first comparative example. FIG. 13 is a graph showing the transition of the integrated flow rate and the pressure reduced from the branch pipe in the second comparative example. FIG. 14 is a graph showing an example of the flow volume curve in the third comparative example.

An embodiment (embodiment) 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. In addition, the components described below include those that can be easily assumed by those skilled in the art and those that are substantially the same. Furthermore, the components described below can be combined as appropriate.

FIG. 1 is a schematic view of a respiratory function test device according to the present embodiment. The respiratory function test device 100 according to the present embodiment is used, for example, to acquire a diagnostic index of COPD. As shown in FIG. 1, the respiratory function test device 100 includes a branch pipe 1, a mask 2, a first blower 71, a second blower 72, a first valve body 51, a first actuator 61, and a second valve. A body 52, a second actuator 62, a flow sensor 81, a pressure sensor 82, an input device 95, an output device 96, and a control device 9 are provided.

The branch tube 1 is a member connected to the mouth and nose of the subject. The branch pipe 1 includes a main pipe 10, a first auxiliary pipe 11, and a second auxiliary pipe 12. The main tube 10 is connected to the subject's mouth and nose via the mask 2. A mask 2 is attached to one end of the main pipe 10. Mask 2 covers the subject's mouth and nose. The other end of the main pipe 10 is connected to the first auxiliary pipe 11.

The first auxiliary pipe 11 includes an opening 110, a closing stopper 11a, and an opening stopper 11b. The opening 110 is arranged at one end of the first auxiliary pipe 11 and is open to the atmosphere. The other end of the first auxiliary pipe 11 is connected to the second auxiliary pipe 12. The main pipe 10 is connected to the first auxiliary pipe 11 at a position between the second auxiliary pipe 12 and the opening 110. The closed stopper 11a and the open stopper 11b are annular protrusions provided on the inner peripheral surface of the first auxiliary pipe 11. The closing stopper 11a is arranged on the opening 110 side with respect to the opening stopper 11b.

The second auxiliary pipe 12 is connected to the first blower 71 and the second blower 72. The connection portion between the first blower 71 and the second auxiliary pipe 12 is located on the opposite side of the first auxiliary pipe 11 from the connection portion between the second blower 72 and the second auxiliary pipe 12. The second auxiliary pipe 12 includes a pressurizing stopper 12a and a depressurizing stopper 12b. The pressurizing stopper 12a and the depressurizing stopper 12b are annular protrusions provided on the inner peripheral surface of the second auxiliary pipe 12. The pressurizing stopper 12a is arranged on the first blower 71 side with respect to the depressurizing stopper 12b.

The first blower 71 is a device for discharging the air inside the branch pipe 1. The first blower 71 is connected to the second auxiliary pipe 12. The first blower 71 sends the air inside the second auxiliary pipe 12 to the outside of the branch pipe 1. The first blower 71 depressurizes the branch pipe 1.

The second blower 72 is a device for supplying air to the inside of the branch pipe 1. The second blower 72 is connected to the second auxiliary pipe 12. The second blower 72 sends the air outside the branch pipe 1 to the inside of the second auxiliary pipe 12. The second blower 72 pressurizes the branch pipe 1.

The first valve body 51 is arranged inside the first auxiliary pipe 11. The first valve body 51 includes a seal member in contact with the inner peripheral surface of the first auxiliary pipe 11. The sealing member is, for example, a V-ring made of synthetic rubber.

The first actuator 61 is a device for moving the first valve body 51. The first actuator 61 includes an electric motor and converts the rotary motion of the electric motor into a linear motion. The first actuator 61 moves the first valve body 51 along the axial direction of the first auxiliary pipe 11. The first actuator 61 moves the first valve body 51 to the open position and the closed position. When the first valve body 51 is in the open position, the first valve body 51 comes into contact with the stopper 11b at the time of opening. As a result, the first valve body 51 blocks the flow between the second auxiliary pipe 12 and the main pipe 10. When the first valve body 51 is in the closed position, the first valve body 51 comes into contact with the closed stopper 11a. As a result, the first valve body 51 blocks the flow between the opening 110 and the main pipe 10.

The second valve body 52 is arranged inside the second auxiliary pipe 12. The second valve body 52 includes a seal member in contact with the inner peripheral surface of the second auxiliary pipe 12. The sealing member is, for example, a V-ring made of synthetic rubber.

The second actuator 62 is a device for moving the second valve body 52. The second actuator 62 includes an electric motor and converts the rotary motion of the electric motor into a linear motion. The second actuator 62 moves the second valve body 52 along the axial direction of the second auxiliary pipe 12. The second actuator 62 moves the second valve body 52 to the depressurized position and the pressurized position. When the second valve body 52 is in the depressurized position, the second valve body 52 comes into contact with the depressurized stopper 12b. As a result, the second valve body 52 blocks the flow between the second blower 72 and the first auxiliary pipe 11. When the second valve body 52 is in the pressurizing position, the second valve body 52 comes into contact with the pressurizing stopper 12a. As a result, the second valve body 52 blocks the flow between the first blower 71 and the first auxiliary pipe 11.

The flow sensor 81 is a device that detects the flow rate of air flowing through the branch pipe 1. The flow sensor 81 is, for example, a differential pressure type. The flow sensor 81 acquires the pressure on both sides of the orifice 811 provided inside the main pipe 10. The flow sensor 81 detects the flow rate of air flowing through the main pipe 10 based on the pressure difference on both sides of the orifice 811.

The pressure sensor 82 is a device that detects the pressure inside the branch pipe 1. The pressure sensor 82 acquires the pressure on the mask 2 side from the orifice 811 and the atmospheric pressure. The pressure sensor 82 detects the relative pressure inside the main pipe 10 with respect to the atmospheric pressure. The pressure sensor 82 outputs a positive value when the pressure inside the main pipe 10 is higher than the atmospheric pressure. The pressure sensor 82 outputs a negative value when the pressure inside the main pipe 10 is lower than the atmospheric pressure.

The input device 95 is a device for inputting information to the control device 9. The input device 95 is, for example, a mouse, a keyboard, or the like. The output device 96 is a device that outputs the information received from the control device 9. The output device 96 is a display device such as a liquid crystal display.

The control device 9 is a computer. The control device 9 includes, for example, a CPU (Central Processing Unit), a ROM (Read Only Memory), and a RAM (Random Access Memory). By linking the CPU, ROM, and RAM, each function of the control device 9 is realized. The control device 9 is electrically connected to the first blower 71, the second blower 72, the first actuator 61, the second actuator 62, the flow sensor 81, the pressure sensor 82, the input device 95, and the output device 96.

FIG. 2 is a block diagram of the control device according to the present embodiment. As shown in FIG. 2, the control device 9 includes a first measurement unit 91 and a second measurement unit 92. The first measurement unit 91 measures the reference ventilation volume TV at rest of the subject. The second measuring unit 92 measures the relationship between the expiratory volume and the expiratory flow rate.

The first measurement unit 91 includes a first storage unit 911, a first control unit 912, and a ventilation volume calculation unit 913. The first control unit 912 stores the information detected by the flow sensor 81 and the pressure sensor 82 in the first storage unit 911 at predetermined time intervals. Further, the first storage unit 911 stores the intake period set pressure and the set pressurization time. The intake period set pressure is, for example, 4 (cmH ₂₀ ). The set pressurization time is, for example, 0.5 (sec). The intake period set pressure and the set pressurization time can be changed by the input device 95.

The first control unit 912 controls the first blower 71, the second blower 72, the first actuator 61, and the second actuator 62. The first control unit 912 identifies the start time of inspiration and the start time of exhalation from the information detected by the flow sensor 81 and the pressure sensor 82. Specifically, the first control unit 912 determines that the time when the sign of the pressure detected by the pressure sensor 82 changes from positive to negative is the start of intake air. The first control unit 912 determines when the sign of the pressure detected by the pressure sensor 82 changes from negative to positive as the start of exhalation.

The ventilation volume calculation unit 913 calculates the reference ventilation volume TV of the subject. The ventilation volume calculation unit 913 specifies the start time of inspiration and the start time of exhalation, similarly to the first control unit 912. The ventilation volume calculation unit 913 integrates the flow rate obtained from the flow sensor 81. The ventilation volume calculation unit 913 sets the integrated flow rate at the start of inspiration to 0. During the intake period, the ventilation volume calculation unit 913 adds the flow rate obtained from the flow sensor 81 to the integrated flow rate. During the expiratory period, the ventilation volume calculation unit 913 subtracts the flow rate obtained from the flow sensor 81 from the integrated flow rate. The ventilation volume calculation unit 913 calculates the integrated flow rate from the start of inspiration to the start of exhalation in one breath as the tidal volume. The ventilation volume calculation unit 913 calculates the reference ventilation volume TV based on a plurality of tidal ventilation volumes when resting breathing is being performed.

The second measurement unit 92 includes a second storage unit 921, a second control unit 922, and a flow volume calculation unit 923. The second control unit 922 stores the information detected by the flow sensor 81 and the pressure sensor 82 in the second storage unit 921 at predetermined time intervals. Further, the second storage unit 921 stores the inspiratory period set pressure, the set pressurizing time, the expiratory period set pressure, the pressure update value, the set decompression number of times, and the trigger value. The intake period set pressure and set pressurization time stored in the second storage unit 921 are equal to the intake period set pressure and set pressurization time stored in the first storage unit 911. The expiratory period setting pressure is, for example, -3 (cmH ₂₀ ). The pressure update value is, for example, -1 (cmH ₂₀ ). The set number of depressurizations is, for example, 10 times. The trigger value is, for example, 0.25. The inspiratory period set pressure, the set pressurization time, the expiratory period set pressure, the pressure update value, the set decompression number and the trigger value can be changed by the input device 95. In addition, the second control unit 922 acquires the reference ventilation volume TV calculated by the ventilation volume calculation unit 913.

The second control unit 922 controls the first blower 71, the second blower 72, the first actuator 61, and the second actuator 62. The second control unit 922 starts the process after the second storage unit 921 acquires the reference ventilation volume TV. The second control unit 922 identifies the start time of inspiration and the start time of exhalation from the information obtained from the second storage unit 921. Specifically, the second control unit 922 determines when the sign of the pressure detected by the pressure sensor 82 changes from positive to negative as the start of intake air. The second control unit 922 integrates the flow rate obtained from the flow sensor 81. The second control unit 922 sets the integrated flow rate at the start of intake to 0. The second control unit 922 determines that the time when the integrated flow rate becomes equal to the reference ventilation volume TV is the start of exhalation. During the intake period, the second control unit 922 adds the flow rate obtained from the flow sensor 81 to the integrated flow rate. During the expiratory period, the second control unit 922 subtracts the flow rate obtained from the flow sensor 81 from the integrated flow rate. Further, the second control unit 922 calculates the product of the reference ventilation volume TV and the trigger value stored in the second storage unit 921 as the trigger expiratory volume X.

The flow volume calculation unit 923 calculates the integrated flow rate and flow velocity of the air flowing through the main pipe 10. Similar to the second control unit 922, the flow volume calculation unit 923 specifies the start time of inspiration and the start time of exhalation, and integrates the flow rate obtained from the flow sensor 81. Further, the flow volume calculation unit 923 calculates the flow velocity by dividing the flow rate obtained from the flow sensor 81 by the flow path area of the main pipe 10. The flow volume calculation unit 923 outputs a flow volume curve which is a graph showing the relationship between the integrated flow rate and the flow velocity.

FIG. 3 is a flowchart showing a process performed by the control device according to the present embodiment. FIG. 4 is a schematic view showing the arrangement of the first valve body and the second valve body during the intake period. FIG. 5 is a graph showing the transition of the integrated flow rate and the pressure applied to the branch pipe. FIG. 6 is a schematic view showing the arrangement of the first valve body and the second valve body during the expiratory period. FIG. 7 is a graph for explaining a method of calculating the reference ventilation volume. FIG. 8 is a schematic view showing the arrangement of the first valve body and the second valve body after the intake air volume reaches the reference ventilation volume. FIG. 9 is a schematic view showing the arrangement of the first valve body and the second valve body when the ratio of the expiratory volume to the reference ventilation volume becomes a predetermined value or more. FIG. 10 is a graph showing the transition of the integrated flow rate and the pressure reduced from the branch pipe. FIG. 11 is a graph showing an example of the flow volume curve in the present embodiment.

The control device 9 starts the process when the start button or the like provided on the input device 95 is pressed. As shown in FIG. 3, the control device 9 first pressurizes the branch pipe 1 during the intake period (step S1). In other words, the control device 9 makes the branch pipe 1 positive pressure during the intake period.

In step S1, the first control unit 912 drives the second blower 72 at the start of intake air. Further, the first control unit 912 moves the first valve body 51 to the closed position and the second valve body 52 to the pressurizing position as shown in FIG. 4 at the start of intake air. As a result, as shown in FIG. 5, the intake period set pressure is applied to the branch pipe 1. During the inspiratory period, the pressure applied to the subject's mouth and nose is higher than atmospheric pressure. Therefore, intake is assisted.

The first control unit 912 stops the second blower 72 when the elapsed time from the start of intake reaches the set pressurization time stored in the first storage unit 911, and the first valve body as shown in FIG. Move 51 to the open position. As a result, atmospheric pressure is applied to the mouth and nose of the subject. Subject breathes naturally. The second blower 72 remains stationary and the first valve body 51 remains in the open position until the start of the next intake.

Next, the control device 9 continues step S1 when the subject's respiration is not stable (steps S2 and No in FIG. 3). When the subject's respiration is stable (step S2 in FIG. 3, Yes), the control device 9 calculates the reference ventilation volume TV (step S3 in FIG. 3).

In step S2, the ventilation volume calculation unit 913 determines that the breathing after the time when the variation in the tidal volume becomes equal to or less than a predetermined value in, for example, a plurality of breaths is a resting breath. The ventilation volume calculation unit 913 may change the intake period set pressure stored in the first storage unit 911 based on the variation in the tidal volume in a plurality of breaths.

In step S3, the ventilation volume calculation unit 913 integrates the flow rates obtained from the flow sensor 81 for a predetermined number of breaths. The predetermined number of times is, for example, three times. As shown in FIG. 7, the ventilation volume calculation unit 913 calculates the estimated resting intake position RI as the average of the integrated flow rate RI1, the integrated flow rate RI2, and the integrated flow rate RI3 at the start of inspiration. The ventilation volume calculation unit 913 calculates the estimated resting expiratory position RE as the average of the integrated flow rate RE1, the integrated flow rate RE2, and the integrated flow rate RE3 at the start of exhalation. The ventilation volume calculation unit 913 calculates the difference between the estimated resting inspiratory position RI and the estimated resting expiratory level RE (estimated resting inspiratory position RI-estimated resting expiratory level RE) as the reference ventilation volume TV.

Next, the control device 9 pressurizes the branch pipe 1 during the intake period (step S4 in FIG. 3). In other words, the control device 9 makes the branch pipe 1 positive pressure during the intake period.

In step S4, the second control unit 922 stops the first blower 71 and drives the second blower 72 at the start of intake air. Further, the second control unit 922 moves the first valve body 51 to the closed position and the second valve body 52 to the pressurizing position as shown in FIG. 4 at the start of intake air. As a result, as shown in FIG. 5, the intake period set pressure is applied to the branch pipe 1. During the inspiratory period, the pressure applied to the subject's mouth and nose is higher than atmospheric pressure. Therefore, intake is assisted.

The second control unit 922 stops the second blower 72 when the elapsed time from the start of intake reaches the set pressurization time stored in the second storage unit 921, and the first valve body is as shown in FIG. Move 51 to the open position. As a result, atmospheric pressure is applied to the mouth and nose of the subject. Subject breathes naturally. Further, the second control unit 922 moves the second valve body 52 to the depressurized position as shown in FIG. 8 until the expiratory amount reaches the trigger expiratory amount X. The expiratory volume is an absolute value of the integrated flow rate when the start of exhalation (when the integrated flow rate reaches the reference ventilation volume TV) is set to 0.

Next, the control device 9 depressurizes the branch pipe 1 when the ratio of the expiratory volume to the reference ventilation volume TV reaches the trigger value (step S5 in FIG. 3). In other words, the control device 9 makes the branch pipe 1 negative pressure after a predetermined time from the start of exhalation.

In step S5, the second control unit 922 drives the first blower 71 and stops the second blower 72. Further, when the expiratory amount reaches the trigger expiratory amount X, the second control unit 922 moves the first valve body 51 to the closed position as shown in FIG. As a result, as shown in FIG. 10, the branch pipe 1 is depressurized by the expiratory period set pressure. During the expiratory period, the pressure applied to the subject's mouth and nose is lower than atmospheric pressure. Therefore, exhalation is assisted.

Next, the control device 9 releases the decompression of the branch pipe 1 when the expiratory volume reaches the reference ventilation volume TV (step S6 in FIG. 3).

In step S6, the second control unit 922 stops the first blower 71 and moves the first valve body 51 to the open position as shown in FIG. As a result, atmospheric pressure is applied to the mouth and nose of the subject. When the expiratory volume reaches the reference ventilation volume TV, it corresponds to the time when the volume of air in the lungs of the subject reaches the functional resident capacity (FRC).

Next, the control device 9 causes the output device 96 to display the flow volume curve (step S7 in FIG. 3).

In step S7, the flow volume calculation unit 923 creates a flow volume curve (see FIG. 11) based on the integrated flow rate and flow velocity stored in steps S4 to S6. The flow volume curve is a graph showing the relationship between the integrated flow rate and the flow velocity. In FIG. 11, the solid line shows the flow volume curve, the lower one-dot chain line shows the pressure of the branch pipe 1 during the inspiratory period, and the upper one-dot chain line shows the pressure of the branch pipe 1 during the expiratory period. The flow volume calculation unit 923 causes the output device 96 to display the flow volume curve.

In the flow volume curve shown in FIG. 11, the integrated flow rate increases toward the left of the horizontal axis, and decreases toward the right of the horizontal axis. That is, the amount of air in the subject's lungs increases toward the left of the horizontal axis, and the amount of air in the subject's lungs decreases toward the right of the horizontal axis. The flow velocity of the exhaled air and the pressure reduced from the branch pipe 1 increase toward the upper side of the vertical axis. The flow velocity of the intake air and the pressure applied to the branch pipe 1 increase toward the bottom of the vertical axis.

Next, the control device 9 updates the expiratory period set pressure when the number of times the branch pipe 1 is decompressed does not reach the set number of decompressions (step S8, No. in FIG. 3) (step S9 in FIG. 3). The control device 9 ends the process when the number of times the branch pipe 1 is depressurized reaches the set number of times of depressurization (step S8, Yes in FIG. 3).

In step S9, the second storage unit 921 updates the expiratory period setting pressure. The second storage unit 921 stores the value obtained by adding the pressure update value to the previous expiratory period set pressure as the next expiratory period set pressure. The pressure for setting the second expiratory period is -4 (cmH ₂₀ ). Since the set number of decompression times is 10, the final expiratory period set pressure is -13 (cmH ₂₀ ). In the second and subsequent steps S7, a plurality of flow volume curves are displayed in an overlapping manner. The flow volume calculation unit 923 resets the integrated flow rate (set to 0) for each breath. Therefore, in the plurality of flow volume curves, the starting point is constant at the point where the integrated flow rate and the flow velocity are 0. Physicians use the shape of the flow volume curve during expiratory period as a diagnostic index for COPD.

FIG. 12 is a graph showing the transition of the integrated flow rate and the pressure applied to the branch pipe in the first comparative example. FIG. 13 is a graph showing the transition of the integrated flow rate and the pressure reduced from the branch pipe in the second comparative example. FIG. 14 is a graph showing an example of the flow volume curve in the third comparative example.

In the first comparative example, the branch pipe 1 is not pressurized during the intake period. When the branch pipe 1 is not pressurized during the inspiratory period, respiration is difficult to stabilize as shown in FIG. Therefore, it takes time for the subject to be able to breathe with high reproducibility. Further, even if the variation in respiration becomes small, the accuracy of the reference ventilation TV becomes low.

On the other hand, in the present embodiment, as shown in FIG. 5, the branch pipe 1 is pressurized during the intake period. In human breathing, the respiratory muscles (mainly the diaphragm) become tense during the inspiratory period, and the respiratory muscles relax during the expiratory period. When the branch tube 1 is pressurized during the inspiratory period when the respiratory muscles are tense, the subject can easily inhale. The faster the air flow towards the lungs, the shorter the time required for inspiration. Since rhythm is likely to occur in breathing, breathing is likely to be stable as shown in FIG. As a result, in the present embodiment, it is possible to shorten the time until the subject can breathe with high reproducibility. In addition, the accuracy of the reference ventilation TV becomes high.

In the second comparative example, as shown in FIG. 13, the branch pipe 1 is depressurized until the exhalation is completed. When the branch tube 1 is decompressed until the exhalation is completed, it becomes difficult for the subject to take the next breath. The subject's breathing is likely to be disturbed after the branch tube 1 is decompressed. Therefore, continuous measurement for obtaining a plurality of flow volume curves is difficult. Each time a flow volume curve is obtained, the subject needs to leave the examination device.

On the other hand, in the present embodiment, as shown in FIG. 10, the decompression of the branch pipe 1 ends when the expiratory volume becomes equal to the reference ventilation volume TV. Therefore, the subject is likely to take the next breath, and the breathing is less likely to be disturbed. Therefore, continuous measurement for obtaining a plurality of flow volume curves is easy.

In the third comparative example, as shown in FIG. 14, the branch pipe 1 is depressurized at the same time when the intake air volume reaches the reference ventilation volume TV. When the branch tube 1 is decompressed at the same time as the start of exhalation in this way, the exhalation is disturbed by the reflex of the subject. For example, a bimodal peak as shown in FIG. 14 may occur on the flow volume curve. The flow volume curve with the bimodal peak as shown in FIG. 14 cannot be used for the evaluation of COPD.

On the other hand, in the present embodiment, as shown in FIG. 10, the branch pipe 1 is depressurized when the ratio of the expiratory volume to the reference ventilation volume TV reaches the trigger value. As a result, the bimodal peak as shown in FIG. 14 is less likely to occur. According to the respiratory function test device 100 according to the present embodiment, it becomes easy to acquire data that can be used as a diagnostic index. Even when stable breathing is performed, the tidal volume of the subject may deviate from the reference ventilation TV by up to about 20% of the reference ventilation TV. Therefore, the trigger value is preferably 0.25 or more. This makes the exhalation less likely to be disturbed.

The respiratory function test device 100 does not necessarily have to include the mask 2. For example, the respiratory function test device 100 may be a tubular mouthpiece that can be held by the mouth instead of the mask 2 that covers the mouth and nose. However, it is preferable that the respiratory function test device 100 includes the mask 2 because the burden on the subject can be reduced.

As described above, the respiratory function test device 100 includes a branch pipe 1, a first blower 71, a second blower 72, a flow sensor 81, a pressure sensor 82, and a control device 9. The branch tube 1 is connected to at least the mouth of the subject. The first blower 71 discharges the air inside the branch pipe 1. The second blower 72 supplies air to the inside of the branch pipe 1. The flow sensor 81 detects the flow rate of the gas flowing through the branch pipe 1. The pressure sensor 82 detects the pressure in the branch pipe 1. The control device 9 is electrically connected to the first blower 71, the second blower 72, the flow sensor 81, and the pressure sensor 82. The control device 9 pressurizes the branch pipe 1 during at least a part of the inspiratory period and calculates the reference ventilation volume TV of the subject. After calculating the reference ventilation volume TV, the control device 9 pressurizes the branch pipe 1 during at least a part of the inspiratory period, and when the ratio of the expiratory volume to the reference ventilation volume TV reaches a predetermined value (trigger value). The branch pipe 1 is depressurized from.

As a result, the branch pipe 1 is pressurized during the inspiratory period, which makes it easier for the subject's respiration to stabilize. As a result, the accuracy of the calculated reference ventilation TV is improved. By depressurizing the branch pipe 1 when the ratio of the expiratory volume to the reference ventilation volume TV reaches a predetermined value, a bimodal peak is less likely to occur in the flow volume curve. Therefore, the respiratory function test device 100 facilitates the acquisition of data that can be used as a diagnostic index.

Further, in the respiratory function test device 100, the control device 9 stops the decompression of the branch pipe 1 when the expiratory volume becomes equal to the reference ventilation volume TV.

As a result, the subject is more likely to take the next breath, and the breathing is less likely to be disturbed. Pulmonary function testing device 100 facilitates continuous measurements to obtain multiple flow volume curves.

The respiratory function test device 100 includes a first valve body 51, a second valve body 52, a first actuator 61, and a second actuator 62. The branch pipe 1 includes a main pipe 10 connected to at least the mouth of the subject, a first auxiliary pipe 11 having an open opening 110 and connected to the main pipe 10, and a second auxiliary pipe 12 connected to the first auxiliary pipe 11. Be prepared. The first valve body 51 is provided in the first auxiliary pipe 11. The second valve body 52 is provided in the second auxiliary pipe 12. The first actuator 61 moves the first valve body 51 to an open position that blocks the flow between the second auxiliary pipe 12 and the main pipe 10 and a closed position that blocks the flow between the opening 110 and the main pipe 10. Let me. The second actuator 62 is at a position at the time of depressurization that blocks the flow between the second blower 72 and the first auxiliary pipe 11, and at the time of pressurization that blocks the flow between the first blower 71 and the first auxiliary pipe 11. The second valve body 52 is moved to the position. The control device 9 is electrically connected to the first actuator 61 and the second actuator 62.

If the first valve body 51 and the second valve body 52 are not provided, it takes time to switch between pressurization and depressurization of the branch pipe 1. Therefore, the timing of switching between pressurization and depressurization of the branch pipe 1 tends to be delayed from the ideal timing. Since the branch tube 1 is likely to be pressurized during the expiratory period or the branch tube 1 is likely to be decompressed during the inspiratory period, respiratory resistance is increased. Further, the amount of air short-circuited between the first blower 71 and the second blower 72 increases. In contrast to such a problem, in the present embodiment, by controlling the positions of the first valve body 51 and the second valve body 52, switching between pressurization and depressurization of the branch pipe 1 becomes faster.

Further, the respiratory function test device 100 can be paraphrased as follows. That is, the respiratory function test device 100 includes the branch pipe 1, the first blower 71, the second blower 72, the first valve body 51, the second valve body 52, the first actuator 61, and the second actuator 62. A flow sensor 81, a pressure sensor 82, and a control device 9 are provided. The branch pipe 1 includes a main pipe 10 connected to at least the mouth of the subject, a first auxiliary pipe 11 having an open opening 110 and connected to the main pipe 10, and a second auxiliary pipe 12 connected to the first auxiliary pipe 11. Be prepared. The first blower 71 discharges the air inside the branch pipe 1. The second blower 72 supplies air to the inside of the branch pipe 1. The first valve body 51 is provided in the first auxiliary pipe 11. The second valve body 52 is provided in the second auxiliary pipe 12. The first actuator 61 moves the first valve body 51 to an open position that blocks the flow between the second auxiliary pipe 12 and the main pipe 10 and a closed position that blocks the flow between the opening 110 and the main pipe 10. Let me. The second actuator 62 is at a position at the time of depressurization that blocks the flow between the second blower 72 and the first auxiliary pipe 11, and at the time of pressurization that blocks the flow between the first blower 71 and the first auxiliary pipe 11. The second valve body 52 is moved to the position. The flow sensor 81 detects the flow rate of the gas flowing through the branch pipe 1. The pressure sensor 82 detects the pressure in the branch pipe 1. The control device 9 is electrically connected to the first blower 71, the second blower 72, the first actuator 61, the second actuator 62, the flow sensor 81, and the pressure sensor 82. The second blower 72 is driven, the first valve body 51 is in the closed position, and the second valve body 52 is in the pressurizing position during at least a part of the intake period. The first valve body 51 is in the open position during a part of the exhalation period including the start of exhalation. In other periods of the expiratory period, the first blower 71 is driven, the first valve body 51 is in the closed position, and the second valve body 52 is in the decompression position.

As a result, inspiration is assisted and breathing is likely to be stable. Further, since natural respiration is performed from the start of exhalation to the time when the branch pipe 1 is decompressed, disturbance of exhalation due to decompression is unlikely to occur. Therefore, bimodal peaks are less likely to occur in the flow volume curve. Therefore, the respiratory function test device 100 facilitates the acquisition of data that can be used as a diagnostic index.

1 Branch pipe 10 Main pipe 11 1st auxiliary pipe 110 Opening 11a Closing stopper 11b Opening stopper 12 2nd auxiliary pipe 12a Pressurizing stopper 12b Depressurizing stopper 100 Pulmonary function testing device 2 Mask 51 1st valve body 52 2nd Valve body 61 1st actuator 62 2nd actuator 71 1st blower 72 2nd blower 81 Flow sensor 82 Pressure sensor 9 Control device 95 Input device 96 Output device

Claims (4)

With a branch tube connected to at least the subject's mouth,
The first blower that discharges the air inside the branch pipe and
A second blower that supplies air to the inside of the branch pipe,
A flow sensor that detects the flow rate of gas flowing through the branch pipe, and
A pressure sensor that detects the pressure inside the branch pipe and
A control device electrically connected to the first blower, the second blower, the flow sensor, and the pressure sensor.
With
The control device pressurizes the branch tube during at least a part of the inspiratory period, and calculates a reference ventilation volume of the subject based on a plurality of tidal volume during resting breathing.
After calculating the reference ventilation volume, the control device pressurizes the branch pipe during at least a part of the inspiratory period, and the branch pipe starts when the ratio of the expiratory volume to the reference ventilation volume reaches a predetermined value. Pulmonary function testing device to reduce the pressure. The respiratory function test device according to claim 1, wherein the control device stops decompression of the branch pipe when the expiratory volume becomes equal to the reference ventilation volume. A main pipe connected to at least the mouth of the subject, a first auxiliary pipe having an open opening and connected to the main pipe, and the branch pipe having a second auxiliary pipe connected to the first auxiliary pipe.
The first valve body provided in the first auxiliary pipe and
The second valve body provided in the second auxiliary pipe and
A first actuator that moves the first valve body to an open position that blocks the flow between the second auxiliary pipe and the main pipe and a closed position that blocks the flow between the opening and the main pipe.
The second valve is located at a decompression position that blocks the flow between the second blower and the first auxiliary pipe, and at a pressurization position that blocks the flow between the first blower and the first auxiliary pipe. The second actuator that moves the body and
With
The respiratory function test device according to claim 1 or 2, wherein the control device is electrically connected to the first actuator and the second actuator. At least part of the period of the inspiratory period, the second blower is driven, located on the first valve body is the closed position, the second valve body is in the pressurized position,
The first valve body is in the open position during a part of the exhalation period including the start of exhalation.
In other periods of the expiratory period, the first blower is driven, the first valve body is in the closed position, and the second valve body is in the decompression position.
The respiratory function test apparatus according to claim 3.

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