Humidification control system, respiration assistance system, humidification control method, and humidification control program

Abstract

This humidification control system comprises an inspired gas sensor (30) that measures the flow rate of inspired gas (G1) and a control device (32) that controls a humidification device (2) on the basis of the measurement value from the inspired gas sensor (30). The control device (32) includes: an inspiration estimation unit that estimates an inspiration start time on the basis of the measurement value from the inspired gas sensor (30); an expiration estimation unit that estimates an expiration start time on the basis of the measurement value from the inspired gas sensor (30); a water supply instruction unit that provides, on the basis of the estimated inspiration start time, an instruction to start supply of water from a pump to a heater of the humidification device (2) before inspiration starts; a heater output increase instruction unit that provides, on the basis of the estimated inspiration start time, an instruction to increase the output of the heater before the inspiration starts; and a heater output reduction instruction unit that provides, on the basis of the estimated expiration start time, an instruction to reduce the output of the heater before expiration starts.

Description

Humidification control system, respiratory assistance system, humidification control method, and humidification control program

[0001] The present invention relates to a humidification control system for controlling a humidifier in a respiratory assistance device.

[0002] High-flow oxygen therapy (HFT) is a type of respiratory therapy that provides breathing support to patients with respiratory problems. This therapy supplies humidified inhaled gas at a high flow rate to the patient, reducing the patient's work of breathing.

[0003] Here, Patent Document 1 describes a respiratory assistance device used in high-flow oxygen therapy. As shown in Patent Document 1, this type of respiratory assistance device is provided with a humidifying device that includes a tank that stores liquid water and a heater that heats the water in the tank in order to supply humidified inhaled gas to the patient.

[0004] Japanese Patent Application Laid-Open No. 2022-119922

[0005] However, conventional humidifiers such as those described in Patent Document 1 generate steam by heating all of the water stored in the tank, making it difficult to intentionally change the amount of water evaporation. This means it is difficult to generate steam at the timing when humidification is needed, and steam is generated constantly, resulting in unnecessary heater power consumption. Furthermore, because water is constantly evaporating, a large amount of water is required, and the cost of preparing water is high, for example, when pure water is used to prevent scale buildup on the tank.

[0006] Therefore, the present invention provides a humidification control system, a respiratory assistance system, a humidification control method, and a humidification control program that are capable of humidifying inhaled gas while reducing running costs.

[0007] A humidification control system according to one aspect of the present invention is a humidification control system that controls a humidifier that converts liquid water supplied by a pump into water vapor by electromagnetic induction heating in a heater and adds the water vapor to inhaled gas supplied to a user's respiratory organs, and includes a respiratory sensor that measures at least one of the user's inhalation and exhalation, and a control device that controls the humidifier based on the measurement value of the respiratory sensor, and the control device includes an inhalation estimation unit that estimates the timing of the inhalation based on the measurement value of the respiratory sensor, an exhalation estimation unit that estimates the timing of the exhalation based on the measurement value of the respiratory sensor, a water supply instruction unit that starts the supply of liquid water from the pump to the heater before the start of the inhalation based on the estimated timing of the inhalation, a heater output increase instruction unit that increases the output of the heater before the start of the inhalation based on the estimated timing of the inhalation, and a heater output decrease instruction unit that decreases the output of the heater before the start of the exhalation based on the estimated timing of the exhalation.

[0008] In the above-mentioned humidification control system, the control device may further include a water supply stop instruction unit that stops the supply of liquid water from the pump to the heater before the start of the exhalation based on the estimated timing of the exhalation.

[0009] In the above humidification control system, the respiratory sensor may be a gas sensor that measures the pressure or flow rate of at least one of the inhaled gas and exhaled gas of the user.

[0010] The humidification control system may further include an intake gas humidity sensor that measures the humidity of the intake gas after humidification by the humidification device, and the water supply stop instruction unit of the control device may adjust the timing for stopping the supply of the liquid water so that the measurement value of the intake gas humidity sensor is equal to or greater than a predetermined target value when the user inhales.

[0011] In the above-mentioned humidification control system, the control device may further include a respiratory data generation unit that generates respiratory data of the user based on the measurement value of the respiratory sensor, and the respiratory data generation unit may update the respiratory data at predetermined time intervals.

[0012] In the above humidification control system, the heater output increase instructing unit may increase the output of the heater before the water supply instructing unit starts supplying water from the pump to the heater.

[0013] In the above humidification control system, the heater output reduction instruction unit may reduce the output of the heater after the water supply stop instruction unit stops the supply of water from the pump to the heater.

[0014] A respiratory assistance system according to one embodiment of the present invention comprises a respiratory assistance device that supplies inhaled gas to a user's respiratory organs, a pump that pressurizes liquid water, a heater that heats the water from the pump by electromagnetic induction heating to generate water vapor, and a humidification device that includes a humidification space that brings the water vapor into contact with the inhaled gas, and the above-mentioned humidification control system that controls the humidification device.

[0015] A humidification control method according to one aspect of the present invention is a humidification control method for controlling a humidifier that converts liquid water supplied by a pump into water vapor by electromagnetic induction heating in a heater and adds the water vapor to inhaled gas supplied to a user's respiratory organs, and includes an inhalation estimation step for estimating the timing of the user's inhalation based on the measurement value of a breathing sensor; an exhalation estimation step for estimating the timing of the user's exhalation based on the measurement value of the breathing sensor; a water supply instruction step for starting the supply of liquid water from the pump to the heater before the start of inhalation based on the estimated inhalation timing; a heater output increase instruction step for increasing the output of the heater before the start of inhalation based on the estimated inhalation timing; and a heater output decrease instruction step for decreasing the output of the heater before the start of exhalation based on the estimated exhalation timing.

[0016] A humidification control program according to one embodiment of the present invention causes a computer to function as an inhalation estimation means for estimating the timing of the user's inhalation based on the measurement value of a breathing sensor, an exhalation estimation means for estimating the timing of the user's exhalation based on the measurement value of the breathing sensor, a water supply instruction means for starting the supply of liquid water from the pump to the heater before the start of inhalation based on the estimated timing of inhalation, a heater output increase instruction means for increasing the output of the heater before the start of inhalation based on the estimated timing of inhalation, and a heater output decrease instruction means for decreasing the output of the heater before the start of exhalation based on the estimated timing of exhalation, in order to convert liquid water supplied by a pump into water vapor by electromagnetic induction heating in a heater and add the water vapor to the inhaled gas supplied to the user's respiratory organs.

[0017] According to the above-described humidification control system, respiratory assistance system, humidification control method, and humidification control program, it is possible to humidify the inhaled gas while reducing running costs.

[0018] It is an overall schematic diagram of a respiratory assistance system according to an embodiment of the present invention. It is a perspective view showing the internal structure of a humidification device in the respiratory assistance system. It is a functional block diagram of a control device in the respiratory assistance system. It is a timing chart showing respiratory data acquired in humidification control in the respiratory assistance system, humidity of inhaled gas, and control timing of each device.

[0019]

[0023] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. (Overall Configuration) As shown in Fig. 1, a respiratory assistance system 100 of this embodiment is used for respiratory therapy such as high-flow therapy. Specifically, the respiratory assistance system 100 includes a respiratory assistance device 1 that supplies inhaled gas G1 to the respiratory organs of a user U, a humidifier 2 that adds moisture to the inhaled gas G1, and a humidification control system 3 that controls the humidifier 2.

[0020] (Respiratory Assistance Device) The respiratory assistance device 1 includes a device main body 10 including a blower 11, a respiratory gas circuit 12 which is a conduit that guides the inhaled gas G1 sent by the blower 11 toward the user U, and a respiratory interface 13 that is worn by the user U and supplies the inhaled gas G1 from the respiratory gas circuit 12 to the respiratory organs of the user U. The respiratory interface 13 is arranged, for example, near the nose and / or mouth of the user U. A nasal cannula, a Venturi mask, or the like is used as the respiratory interface 13. In this embodiment, the exhaled gas G2 from the user U does not flow into the respiratory gas circuit 12 but is released directly into the atmosphere.

[0021] (Humidifier) ​​The humidifier 2 is provided in the respiratory gas circuit 12 between the device main body 10 and the respiratory interface 13, and humidifies the inhaled gas G1 flowing through the respiratory gas circuit 12. As an example, as shown in Fig. 2, the humidifier 2 has a housing 20 that defines a humidification space S therein, an inhaled gas inlet 21 and an inhaled gas outlet 22 that are formed in the housing 20 and communicate with the humidification space S, a heater 23 that is arranged in the housing 20 adjacent to the humidification space S, and a water supply unit 24 that supplies liquid water W into the housing 20 toward the heater 23.

[0022] The inhaled gas inlet 21 and the inhaled gas outlet 22 are connected to the breathing gas circuit 12. The water supply unit 24 has a tank 25 that stores liquid water W, a pump (micropump) 26 that pumps the water W in the tank 25, and an actuator 27 such as a solenoid that switches between supplying and stopping the water supply to the heater 23 by opening and closing a water flow path C between the pump 26 and the housing 20. The actuator 27 is controlled by a water supply instruction unit 303 and a water supply stop instruction unit 305 of the control device 32, which will be described in detail later.

[0023] The heater 23 is an induction heater that generates steam by electromagnetic induction heating water pumped by a pump 26, resulting in excellent responsiveness. Specifically, the heater 23 includes a coil 200 that generates a magnetic field, a heating element 201 formed, for example, of a porous metal, an insulator 202 that provides electrical insulation between the coil 200 and the heating element 201, and ferrite 203, a magnetic material that improves the efficiency of magnetic coupling between the coil 200 and the heating element 201. When the water W pumped by the pump 26 comes into contact with the heating element 201, the generated heated steam flows into the humidifying space S and comes into contact with the intake gas G1, thereby humidifying and warming the intake gas G1.

[0024] (Humidification Control System) Next, a detailed description will be given of the humidification control system 3. Returning to Fig. 1 , the humidification control system 3 includes an intake gas sensor 30 (breathing sensor) that measures the flow rate of the intake gas G1, an intake gas humidity sensor 31 that measures the humidity of the intake gas G1, and a control device 32 that controls the humidifier 2 based on the measurement values ​​of the intake gas sensor 30 and the intake gas humidity sensor 31.

[0025] The intake gas sensor 30 is provided in the respiratory gas circuit 12 between the blower 11 and the humidifier 2, and measures the flow rate of the intake gas G1 in real time.

[0026] The intake gas humidity sensor 31 is provided in the respiratory gas circuit 12 between the respiratory interface 13 and the humidifier 2, and measures the humidity of the intake gas G1 after it has been humidified by the humidifier 2 in real time.

[0027] The control device 32 is provided in the device main body 10 of the respiratory assistance device 1, and acquires measurements from the inhaled gas sensor 30 and the inhaled gas humidity sensor 31 to control the humidifier 2 and the blower 11. In other words, the control device 32 is a computer composed of a CPU, RAM, ROM, etc., and performs various controls. The CPU is a so-called central processing unit, and executes various programs to realize various functions. The RAM is used as a working area and storage area for the CPU, and the ROM stores the operating system and programs executed by the CPU.

[0028] As shown in Figure 3, the control device 32 in this embodiment includes a respiratory data generation unit 300, an inhalation estimation unit 301, an exhalation estimation unit 302, a water supply instruction unit 303, a heater output increase instruction unit 304, a water supply stop instruction unit 305, and a heater output decrease instruction unit 306.

[0029] The respiratory data generating unit 300 generates respiratory data relating to the respiratory waveform of the user U based on the measurement values ​​of the inhaled gas sensor 30. The respiratory data generating unit 300 corrects deviations in breathing timing by updating the respiratory data at predetermined time intervals. The respiratory data is, for example, rectangular wave data corresponding to the respiratory waveform, with high levels indicating inhalation and low levels indicating exhalation (see FIG. 4).

[0030] The inhalation estimation unit 301 estimates the timing of inhalation (inhalation start timing) T1 by the user U based on the respiration data generated by the respiration data generation unit 300 (see FIG. 4).

[0031] The exhalation estimation unit 302 estimates the timing of exhalation (exhalation start timing) T2 by the user U based on the respiration data generated by the respiration data generation unit 300.

[0032] The water supply instruction unit 303 starts supplying liquid water W from the pump 26 of the humidifier 2 to the heater 23 before the start of inhalation, based on the inhalation start timing T1 estimated by the inhalation estimation unit 301. That is, the actuator 27 in the humidifier 2 is operated to open the water flow path C, and the supply of water W from the pump 26 to the heater 23 is started.

[0033] The heater output increase instruction unit 304 increases the output of the heater 23 of the humidifier 2 before the start of intake, based on the intake start timing T1 estimated by the intake estimation unit 301. In this embodiment, the heater output increase instruction unit 304 turns on the power of the heater 23 before the start of intake, and starts supplying power to the heater 23, thereby increasing the output of the heater 23. In this embodiment, the heater output increase instruction unit 304 turns on the power of the heater 23 before the water supply instruction unit 303 starts supplying water W (see FIG. 4).

[0034] The water supply stop instruction unit 305 stops the supply of liquid water W from the pump 26 of the humidifier 2 to the heater 23 before the start of exhalation, based on the exhalation start timing T2 estimated by the exhalation estimation unit 302. That is, it operates the actuator 27 of the humidifier 2 to close the water flow path C, thereby stopping the supply of water W from the pump 26 to the heater 23. In this embodiment, the water supply stop instruction unit 305 adjusts the timing to stop the supply of liquid water W, i.e., the timing to operate the actuator 27, so that the measurement value of the inspiration gas humidity sensor 31 is maintained at or above a predetermined target value D at least during the user U's inspiration (see FIG. 4 ).

[0035] The heater output reduction instruction unit 306 reduces the output of the heater 23 of the humidifier 2 before the start of exhalation, based on the exhalation start timing T2 estimated by the exhalation estimation unit 302. In this embodiment, the heater output reduction instruction unit 306 reduces the output of the heater 23 by turning off the power to the heater 23 before the start of exhalation and stopping the supply of power to the heater 23. In this embodiment, the heater output reduction instruction unit 306 turns off the power to the heater 23 after the water supply stop instruction unit 305 operates the actuator 27 to close the water flow path C and stop the supply of water W to the heater 23 (see FIG. 4 ).

[0036] As shown in Figure 4, the temperature of the intake gas G1 at the outlet of the humidifier 2 (intake gas outlet temperature) is measured by a temperature sensor not shown, and the temperature of the intake gas G1 at the outlet of the humidifier 2 rises in response to an increase in the output of the heater 23 and the timing of water supply to the heater 23.

[0037] (Operation and Effect) According to the breathing assistance system 100 of this embodiment described above, the humidifier 2 is controlled based on the breathing state of the user U measured by the intake gas sensor 30, and the intake gas G1 is humidified when the user U inhales. That is, before the start of inhalation, the output of the heater 23 is increased to start humidifying the intake gas G1, and before the start of exhalation, the output of the heater 23 is reduced to end humidifying the intake gas G1. Therefore, by humidifying the intake gas G1 in a pulsed (intermittent) manner only when inhalation is required, it is possible to reduce the power consumption of the heater 23 and the amount of water used to humidify the intake gas G1, and it is possible to humidify the intake gas G1 with reduced running costs.

[0038] Furthermore, since the control device 32 is provided with the water supply stop instruction unit 305, water W does not need to be supplied to the heater 23 when humidification is not being performed, and the amount of water W supplied (consumption) can also be reduced.

[0039] Furthermore, by measuring the breathing condition of the user U using the intake gas sensor 30, the breathing condition can be accurately grasped, the intake start timing T1 and the exhalation start timing T2 of the user U can be accurately estimated, and the humidification time of the intake gas G1 can be minimized.

[0040] In addition, an intake gas humidity sensor 31 is provided to measure the humidity of the intake gas G1 after humidification, and the timing for stopping the supply of water W to the heater 23 is adjusted so that the measurement value of the intake gas humidity sensor 31 is above a predetermined target value when the user U inhales.This makes it possible to minimize the humidification time while ensuring a sufficient amount of humidification, and further reduces the power consumption of the heater 23 and the consumption of water W used to humidify the intake gas G1.

[0041] Furthermore, by the respiratory data generating unit 300 of the control device 32 updating the respiratory data at predetermined time intervals, the inhalation start timing T1 and exhalation start timing T2 can be accurately estimated at all times even if there is a change in the respiratory condition of the user U.

[0042] Furthermore, the heater output increase instruction unit 304 of the control device 32 turns on the heater 23 to increase the output of the heater 23 before the supply of water W to the heater 23 is started, so that the water W can be supplied to the heater 23 with the temperature of the heater 23 already increased. Therefore, the water W supplied to the heater 23 can be evaporated in a short time, and heated steam can be generated efficiently.

[0043] In addition, the heater output reduction instruction unit 306 of the control device 32 is configured to turn off the heater 23 and reduce the output of the heater 23 after the supply of water W to the heater 23 is stopped, so that the supplied water W can be sufficiently heated in the heater 23 and heated steam can be generated efficiently.

[0044] The present invention is not limited to the above-described embodiment, and it goes without saying that various modifications can be made without departing from the spirit of the present invention.

[0045] For example, the sensor used to generate the respiratory data is not limited to the above-described intake gas sensor 30 that measures the flow rate of the intake gas G1, but may be, for example, a pressure sensor that measures the pressure of the intake gas G1, an expiration gas sensor that measures the pressure or flow rate of the expiration gas G2, or a combination of an intake gas sensor and an expiration gas sensor. In this case, for example, the expiration gas sensor may be installed in a Venturi mask or the like that serves as the respiratory interface 13.

[0046] The structure of the heater 23 is not limited to the above, and may be any structure that heats at least by electromagnetic induction.

[0047] Furthermore, the respiration data generating section 300 of the control device 32 may generate the respiration waveform of the user U itself as respiration data.

[0048] Furthermore, the inhalation estimation unit 301 of the control device 32 is not necessarily limited to estimating the inhalation start timing T1, but may estimate any timing during inhalation. In this case, the water supply instruction unit 303 and the heater output increase instruction unit 304 of the control device 32 may estimate the inhalation start timing from any timing during inhalation that has been estimated. Similarly, the exhalation estimation unit 302 of the control device 32 is not necessarily limited to estimating the exhalation start timing T2, but may estimate any timing during exhalation. In this case, the water supply stop instruction unit 305 and the heater output decrease instruction unit 306 of the control device 32 may estimate the exhalation start timing from any timing during exhalation that has been estimated.

[0049] Furthermore, the water supply instruction unit 303 and the water supply stop instruction unit 305 of the control device 32 are not limited to controlling the operation of the actuator 27, and may supply and stop the supply of water W by directly controlling the operation of the pump 26. In particular, if the pump 26 is a pump capable of high-speed response, the pump 26 may be provided with the function of the actuator 27, such as a solenoid.

[0050] Furthermore, the water supply instruction unit 303 of the control device 32 may supply only a necessary and sufficient amount of water when supplying liquid water W from the pump 26 to the heater 23. For example, the water supply instruction unit 303 may appropriately adjust the amount of water W supplied so that the measurement value of the intake gas humidity sensor 31 at the inhalation start timing T1 of the user U is close to a predetermined target value D and does not fall below the target value D.

[0051] According to the humidification control system of the present invention, it is possible to humidify intake gas while keeping running costs low.

[0052] REFERENCE SIGNS LIST 1 Respiratory assistance device 2 Humidification device 3 Humidification control system 11 Blower 23 Heater 26 Pump 30 Inhaled gas sensor (respiratory sensor) 31 Inhaled gas humidity sensor 32 Control device 100 Respiratory assistance system 200 Coil 300 Respiratory data generation unit 301 Inhaled gas estimation unit 302 Exhaled gas estimation unit 303 Water supply instruction unit 304 Heater output increase instruction unit 305 Water supply stop instruction unit 306 Heater output decrease instruction unit G1 Inhaled gas T1 Inhalation start timing T2 Exhalation start timing U User W Water

Claims

1. A humidification control system that controls a humidification device that converts liquid water supplied by a pump into water vapor through electromagnetic induction heating in a heater and adds the water vapor to inhaled gas supplied to a user's respiratory organs, comprising: a breathing sensor that measures at least one of the inhalation and exhalation of the user; and a control device that controls the humidification device based on the measurement value of the breathing sensor, wherein the control device comprises: an inhalation estimation unit that estimates the timing of the inhalation based on the measurement value of the breathing sensor; an exhalation estimation unit that estimates the timing of the exhalation based on the measurement value of the breathing sensor; a water supply instruction unit that starts the supply of liquid water from the pump to the heater before the start of the inhalation based on the estimated timing of the inhalation; a heater output increase instruction unit that increases the output of the heater before the start of the inhalation based on the estimated timing of the inhalation; and a heater output decrease instruction unit that decreases the output of the heater before the start of the exhalation based on the estimated timing of the exhalation.

2. A humidification control system as described in claim 1, wherein the control device further includes a water supply stop instruction unit that stops the supply of liquid water from the pump to the heater before the start of the exhalation based on the estimated timing of the exhalation.

3. The humidification control system according to claim 1, wherein the respiratory sensor is a gas sensor that measures the pressure or flow rate of at least one of the inhaled gas and the exhaled gas of the user.

4. A humidification control system as described in claim 2, further comprising an intake gas humidity sensor that measures the humidity of the intake gas after humidification by the humidification device, and the water supply stop instruction unit of the control device adjusts the timing for stopping the supply of the liquid water so that the measurement value of the intake gas humidity sensor becomes equal to or exceeds a predetermined target value when the user inhales.

5. The humidification control system of claim 1, wherein the control device further comprises a respiratory data generation unit that generates respiratory data from the user based on the measurement value of the respiratory sensor, and the respiratory data generation unit updates the respiratory data at predetermined time intervals.

6. The humidification control system according to claim 1, wherein the heater output increase instruction section increases the output of the heater before the water supply instruction section starts to supply water from the pump to the heater.

7. A humidification control system according to claim 2, wherein the heater output reduction instruction unit reduces the output of the heater after the water supply stop instruction unit stops the supply of water from the pump to the heater.

8. A respiratory assistance system comprising: a respiratory assistance device for supplying inhaled gas to a user's respiratory organs; a humidification device comprising a pump for pressurizing liquid water, a heater for heating the water from the pump by electromagnetic induction heating to generate water vapor, and a humidification space for bringing the water vapor into contact with the inhaled gas; and a humidification control system described in any one of claims 1 to 7 for controlling the humidification device.

9. A humidification control method for controlling a humidifier that converts liquid water supplied by a pump into water vapor by electromagnetic induction heating in a heater and adds the water vapor to inhaled gas supplied to a user's respiratory organs, comprising: an inhalation estimation step for estimating the timing of the user's inhalation based on the measurement value of a breathing sensor; an exhalation estimation step for estimating the timing of the user's exhalation based on the measurement value of the breathing sensor; a water supply instruction step for starting the supply of liquid water from the pump to the heater before the start of inhalation based on the estimated timing of the inhalation; a heater output increase instruction step for increasing the output of the heater before the start of inhalation based on the estimated timing of the inhalation; and a heater output decrease instruction step for decreasing the output of the heater before the start of exhalation based on the estimated timing of the exhalation.

10. A humidification control program that causes a computer to function as: an inhalation estimation means for estimating the timing of the user's inhalation based on the measurement value of a breathing sensor; an exhalation estimation means for estimating the timing of the user's exhalation based on the measurement value of a breathing sensor; a water supply instruction means for starting the supply of liquid water from the pump to the heater before the start of inhalation based on the estimated timing of the inhalation; a heater output increase instruction means for increasing the output of the heater before the start of inhalation based on the estimated timing of the inhalation; and a heater output decrease instruction means for decreasing the output of the heater before the start of exhalation based on the estimated timing of the exhalation, in order to convert liquid water supplied by a pump into water vapor by electromagnetic induction heating in a heater and add the water vapor to the inhaled gas supplied to the user's respiratory organs.

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