How to operate a breathing air humidifier

Abstract

This document provides a method for operating a respiratory air humidifier. [Solution] The breathing air humidifier (1) comprises a breathing air inlet (3), a breathing air outlet (5), and an electric heating element (9). The breathing air humidifier (1) is switchable between a humidification mode and a preparation mode for preparing the breathing air humidifier (1) for operation in humidification mode. A method for operating the breathing air humidifier (1) includes switching the breathing air humidifier (1) to preparation mode and operating the breathing air humidifier (1) in preparation mode so that when the breathing air humidifier (1) is turned on or off, excess heat based on the operation of the breathing air humidifier (1) in humidification mode prior to turning on or off can be discharged from inside the breathing air humidifier (1), with the heating element (9) deactivated.

Description

Technical Field

[0001] The present invention relates to a method for operating a breathing air humidifier. The present invention further relates to a control unit, a computer program and a computer-readable medium for carrying out this method, and to a breathing air humidifier.

Background Art

[0002] Patients receiving mechanical ventilation may suffer from dryness of the airways. In such cases, a breathing air humidifier can be used to additionally humidify the inhaled breathing air, which can be brought to an appropriate temperature by an electric heating element. Thereby, drying of the mucous membranes can be avoided or at least alleviated. If the ventilation therapy (respiratory therapy) is interrupted for a short time, the breathing air inside the breathing air humidifier may continue to be passively humidified and / or heated because the heating element remains warm even when it is turned off. As a result, after the resumption of the ventilation therapy, the breathing air inhaled during the first breath may be felt to be unpleasantly warm and / or unpleasantly moist.

Summary of the Invention

Problems to be Solved by the Invention

[0003] One of the problems of the present invention can be regarded as providing a method for operating a breathing air humidifier that can prevent the breathing air inhaled when the breathing air humidifier is turned on after a short interruption of its operation from being felt unpleasantly warm and / or unpleasantly moist. Another problem of the present invention can be regarded as providing a control unit, a computer program and a computer-readable medium for carrying out such a method, and a corresponding breathing air humidifier.

Means for Solving the Problems

[0004] These problems are solved by the subject matter of the independent claims. Advantageous embodiments of the present invention are shown in the dependent claims, the following description, and the accompanying drawings.

[0005] A first aspect of the present invention relates to a method for operating a respiratory air humidifier, particularly for a ventilator. The respiratory air humidifier comprises a respiratory air inlet, a respiratory air outlet, and an electric heating element. The respiratory air humidifier is switchable between a humidification mode and a preparation mode for preparing the respiratory air humidifier for operation in humidification mode, and is designed in humidification mode to humidify respiratory air supplied at the respiratory air inlet, which is temperature-controlled by the heating element (i.e., brought to a temperature that feels comfortable during inhalation by controlling the heating element), and to provide the humidified respiratory air at the respiratory air outlet. The method includes switching the respiratory air humidifier to a preparation mode and operating the respiratory air humidifier in preparation mode in order to allow (or accelerate) the dissipation of excess heat from inside the respiratory air humidifier based on the operation of the respiratory air humidifier in humidification mode prior to turning the respiratory air humidifier on or off. When the respiratory air humidifier is operated in preparation mode, the heating element is deactivated.

[0006] In other words, each time the respiratory air humidifier is turned on or off, or more precisely, each time it is recognized that the respiratory air humidifier is to be turned on or off (or should be turned on or off), the respiratory air humidifier can be automatically operated in a preparation mode for a specific period of time to allow the heating element and / or the air inside the respiratory air humidifier to be sufficiently cooled passively and / or actively before restarting the humidification mode, for example, before restarting ventilation therapy that has been interrupted for a short time (e.g., less than 10 minutes, less than 5 minutes, or less than 3 minutes). Alternatively, the switch to preparation mode can be temperature-dependent. In this case, the switch to preparation mode can be made only when the inside of the respiratory air humidifier reaches a certain temperature when the respiratory air humidifier is turned on or off (see below).

[0007] For example, excess heat can be passively and / or actively dissipated by appropriately controlling one or more electro-pneumatic actuators.

[0008] The breathing air humidifier can be operated in a ready mode for a fixed, specified operating duration (e.g., 10 seconds to 5 minutes). Alternatively, the operating duration can be specified based on the current (measured and / or estimated) temperature inside the breathing air humidifier.

[0009] The operation of the respiratory air humidifier in preparation mode can also be restricted to preventing it from switching to humidification mode and / or preventing the heating element from activating.

[0010] Unlike the preparation mode, the humidification mode can be the primary operating mode of the breathing air humidifier. The breathing air humidifier can be operated differently in preparation mode and humidification mode. Basically, in preparation mode, the breathing air humidifier can be operated such that the probability of the breathing air provided at the breathing air outlet feeling uncomfortablely warm and / or uncomfortablely humid during inhalation immediately after the breathing air humidifier is turned on is significantly reduced compared to the corresponding operation in humidification mode.

[0011] The heating element can be activated each time the breathing air humidifier is turned on and / or switched to humidification mode, and / or deactivated each time the breathing air humidifier is turned off and / or switched to preparation mode. In other words, the heating element can be activated during the (full) operation of the breathing air humidifier in humidification mode and / or deactivated during the (full) operation of the breathing air humidifier in preparation mode. In the operating state, the heating element can be kept continuously on. In this case, the heating output of the heating element can be appropriately varied to temperature-regulate the breathing air, for example, by changing the current flowing through the heating element and / or the voltage applied to the heating element (e.g., by pulse width modulation). Additionally or alternatively, in the operating state, the (average) heating output of the heating element can be controlled by switching the heating element on and off several times. In contrast, when the device is shut down, the heating element can be continuously switched off, that is, electrically disconnected from the power supply, so that the breathing air is not heated by the heating element, or at least not intentionally or actively heated.

[0012] When operating a breathing air humidifier in humidification mode, it is possible to switch the breathing air humidifier back to preparation mode only after it has been previously turned off. In other words, once a breathing air humidifier has been operated in preparation mode, it may only be possible to switch it back to preparation mode once it has been turned on or off again. For example, the operation of a breathing air humidifier in humidification mode can only be interrupted by turning the breathing air humidifier off, and not by switching it back to preparation mode.

[0013] When turned off, the breathing air humidifier can be switched off without power being supplied. In other words, when turned off, the breathing air humidifier can be electrically disconnected from power sources, for example, the power grid and / or batteries. Alternatively, when turned off, the breathing air humidifier can be switched to power-saving mode. In power-saving mode, the (turned-off) breathing air humidifier can continue to be powered (for example, via an additional battery), but the energy consumed in this case is significantly less than when it is turned on. In particular, in power-saving mode, the heating element can be kept shut off. Therefore, when the breathing air humidifier is turned on, for example, when the breathing air humidifier is switched to humidification mode (rather than preparation mode), it is possible to terminate power-saving mode again. Alternatively, when the breathing air humidifier is turned on and switched to preparation mode, power-saving mode while on can be maintained. In other words, the (turned-on) breathing air humidifier can consume significantly less energy in preparation mode than in humidification mode.

[0014] "Breathing air" can be understood as a single breathing gas or a mixture of multiple breathing gases used to ventilate a patient. "Breathing gas" can be understood as, for example, carbon dioxide, oxygen, nitrogen, water vapor, or anesthetic gases.

[0015] Humidification of breathing air can be understood as a combination of intentional mixing of breathing air with water vapor and / or water droplets and intentional heating of the breathing air.

[0016] The method can be implemented, for example, on a computer.

[0017] A second aspect of the present invention relates to a control unit configured to perform the methods described above and below.

[0018] The control unit may include data processing means. The data processing means may be implemented as hardware and / or software, and / or may include a processor. The processor may be configured to perform a (computer-implemented) method. In addition to the processor, the control unit may include at least one of the following data processing means: a memory device, a bus system for data communication between the memory device and the processor, and a data communication interface for wireless and / or wired data communication with peripheral devices. Alternatively, the control unit may be implemented only as hardware, for example, as hardware in the form of an ASIC or FPGA element.

[0019] It should be noted that the characteristics of the methods described above and below may also be characteristics of the control unit (and vice versa).

[0020] A third aspect of the present invention relates particularly to a respiratory air humidifier for a ventilator. The respiratory air humidifier comprises a respiratory air inlet, a respiratory air outlet, an electric heating element, and a control unit, as described above and below. The respiratory air humidifier is switchable between a humidification mode and a preparation mode for preparing the respiratory air humidifier for operation in humidification mode, and is designed in humidification mode to humidify respiratory air supplied at the respiratory air inlet, which is temperature-controlled by the heating element, and to provide the humidified respiratory air at the respiratory air outlet.

[0021] A respiratory air inlet may be connectable to a ventilator for invasive and / or non-invasive ventilation of a patient, for example, to allow humidification of the respiratory air provided by the ventilator before it is inhaled by the patient. "Ventilator" can also be understood as an anesthesia machine, or a cough assist device, also called a sputum clearance assist device, for assisting a patient's cough.

[0022] The respiratory air outlet can be connected to the patient's respiratory device, for example, via one or more respiratory hoses and / or patient interfaces (e.g., masks, nasal cannulas and / or tubes), thereby allowing the patient to be ventilated with humidified respiratory air.

[0023] A breathing air humidifier can be designed to humidify breathing air by mixing it with water vapor and / or water droplets on the one hand, and by temperature control through direct and / or indirect contact with a heating element on the other hand. For example, a breathing air humidifier can be designed to generate water vapor for humidifying breathing air by heating water with a heating element, and / or water droplets, in particular aerosols, for humidifying breathing air by spraying water with a atomizer such as a piezoelectric ultrasonic atomizer.

[0024] The control unit can be configured to control a heating element and / or one or more electro-pneumatic actuators, for example, when the breathing air humidifier is operating in humidification mode, so that the actual temperature of the breathing air provided at the breathing air outlet approaches a desired comfort temperature, which is perceived as comfortably warm when inhaled. The comfort temperature may be, for example, 30°C to 38°C.

[0025] Similarly, the control unit can be configured to control the heating element and / or one or more electro-pneumatic actuators so that, when the breathing air humidifier is operating in humidification mode, the actual relative humidity of the breathing air provided at the breathing air outlet relative to the respective ambient temperature approaches a desired relative humidity that makes the breathing air feel comfortably humid when inhaled.

[0026] The term "electric heating element" can generally be understood as an electrically controllable heating element, particularly a heating resistor. The heating element can include, for example, a heating rod, a heating coil, and / or a heating plate. The heating element can be designed to regulate the temperature directly for breathing air and / or indirectly by heating a liquid that the breathing air contacts, for example, when the breathing air flows through a breathing air humidifier.

[0027] The breathing air humidifier can be implemented as a stand-alone device and / or as a component of a medical engineering device, particularly a ventilator.

[0028] Another aspect of the present invention relates to a computer program and a computer-readable medium on which the computer program is stored.

[0029] When the computer program is executed by the control units described above and below, the computer program includes instructions for causing a control unit, for example, a processor of the control unit, to execute the methods described above and below.

[0030] The computer-readable medium can be a volatile or non-volatile data storage device. For example, the computer-readable medium can be a hard disk, a USB storage device (USB = universal serial bus), a RAM (random-access memory), a ROM (read-only memory), an EPROM (erasable programmable read-only memory), an EEPROM (electrically erasable programmable read-only memory), a flash memory, or a combination of at least two of these examples. The computer-readable medium can be a data communication network or a cloud that enables the program code to be downloaded (e.g., via the Internet).

[0031] It should be noted that the characteristics of the methods described above and below may also be characteristics of computer programs and / or computer-readable media (and vice versa).

[0032] Various embodiments of the present invention are described below. These embodiments should not be understood as limiting the scope of the present invention.

[0033] According to one embodiment, the method is as follows: When the breathing air humidifier is turned on, Following operation in the preparation mode of the breathing air humidifier, it may further include switching the breathing air humidifier to humidification mode and operating it in humidification mode until, for example, the breathing air humidifier is turned off again. In other words, the breathing air humidifier can be automatically switched to humidification mode following the preparation mode. For example, the breathing air humidifier can be operated in preparation mode until it is recognized (e.g., by the breathing air humidifier's control unit) that certain switching criteria for switching the breathing air humidifier to humidification mode have been met. Such switching criteria may be, for example, the elapsed time of operation of the breathing air humidifier in preparation mode from the time the breathing air humidifier is turned on or off, and / or the arrival of a predetermined temperature inside the breathing air humidifier. The breathing air humidifier switches to preparation mode only once each time it is turned on, and after the breathing air humidifier has switched to humidification mode, it may only be possible to switch back to preparation mode when the breathing air humidifier is turned off, or when it is turned off and then turned on again.

[0034] According to one embodiment, the method may further include receiving a temperature value indicating the current temperature of the breathing air inside the breathing air humidifier when the breathing air humidifier is turned on or off, comparing the temperature value with a threshold indicating the temperature threshold at which the breathing air feels comfortable during inhalation, and switching the breathing air humidifier to a ready mode and operating the breathing air humidifier in the ready mode if the temperature value exceeds the threshold. In other words, the switching of the breathing air humidifier to the ready mode can be temperature-controlled. This has the advantage of operating the breathing air humidifier in the ready mode only when actually needed. The temperature value can be a measured value, i.e., a value determined by a temperature sensor, and / or an estimated value.

[0035] Additionally or alternatively, if the temperature value does not exceed a threshold, it is possible to prevent the breathing air humidifier from switching to preparation mode.

[0036] According to one embodiment, the method is as follows: When the breathing air humidifier is turned on, If the temperature value does not exceed a threshold, the breathing air humidifier may be switched to humidification mode and may operate in humidification mode until, for example, the breathing air humidifier is turned off again. In other words, if the breathing air inside the breathing air humidifier has cooled sufficiently since the last operation in humidification mode, the breathing air humidifier can be switched directly to humidification mode when it is turned on. This avoids unnecessary operation of the preparation mode.

[0037] According to one embodiment, temperature values ​​can be received in multiple consecutive time steps and compared with a threshold value at each time step. In this case, the breathing air humidifier can be operated in preparation mode until the temperature value no longer exceeds the threshold value in one of the time steps. This makes it possible to automatically terminate the preparation mode depending on the temperature, for example, in combination with an automatic switching of the breathing air humidifier from preparation mode to humidification mode. Conversely, for example, the automatic switching of the breathing air humidifier from humidification mode to preparation mode can be performed in response to the breathing air humidifier being turned off or turned off and then turned on again, as mentioned above.

[0038] According to one embodiment, the method may further include calculating a temperature value using a mathematical model of a breathing air humidifier. In this case, at least one input value can be received and input to the mathematical model. The mathematical model can be configured to convert at least one input value into a temperature value and output the temperature value as an output value. At least one input value is one of the following variables, i.e., - (Current) heating output of the heating element, - The (current) filling level of containers for storing liquids for humidifying breathing air, such as water or liquids containing water. - The (e.g., average) duration of at least one heating phase in which the heating element was operating, prior to turning it on or off. - The (e.g., average) duration of at least one cooling phase in which the heating element was inactive prior to turning on or off. - (Current) ambient temperature in the surrounding environment of the breathing air humidifier. - The current relative air humidity relative to the ambient temperature in the surrounding environment of a breathing air humidifier. - (Current) ambient pressure in the surrounding environment of the breathing air humidifier It is possible to show at least one of the following.

[0039] An "input value" can be understood as a measured value and / or an estimated value that quantifies each variable (one or more). At least one input value can be received, for example, at multiple consecutive time steps and input into the mathematical model. In this case, the mathematical model can output a temperature value at each time step as an output value assigned to the input value for that time step or to multiple input values. This embodiment makes it possible to determine the temperature value with sufficient accuracy without using a separate temperature sensor.

[0040] According to one embodiment, the operation of the breathing air humidifier in preparation mode may include generating a control signal to control at least one electro-pneumatic actuator to generate an airflow for discharging excess heat through the breathing air inlet and / or through the breathing air outlet and / or through at least one vent of the breathing air humidifier separated from the breathing air inlet and breathing air outlet.

[0041] Vents can be formed, for example, in the housing of a respiratory air humidifier and / or the housing of a ventilator. The term “electro-pneumatic actuator” can generally be understood above and below as an electrically controllable actuator for controlling airflow. For example, an electro-pneumatic actuator can be a blower and / or an electrically controllable valve, such as a solenoid valve. By using such active heat dissipation, the cooling of the respiratory air humidifier can be significantly accelerated compared to embodiments using purely passive heat dissipation.

[0042] According to one embodiment, the operation of a respiratory air humidifier in preparation mode may include generating a control signal to control at least one electro-pneumatic actuator to prevent respiratory air from being supplied at the respiratory air outlet. In this way, it is possible to prevent the patient from inhaling respiratory air that is, in some cases, excessively warm and / or excessively humid.

[0043] According to one embodiment, the operation of a breathing air humidifier in preparation mode may include generating a control signal to control at least one electro-pneumatic actuator in order to provide breathing air at the breathing air outlet at a (significantly) lower pressure and / or (significantly) lower volumetric flow rate and / or a different flow direction than when the breathing air humidifier is operating in humidification mode. Lower pressure or lower volumetric flow rate can prevent the breathing air from feeling uncomfortably warm and / or uncomfortably humid upon inhalation, even if it has not yet cooled sufficiently. The volumetric flow rate or pressure in preparation mode can differ from, for example, the volumetric flow rate or pressure in humidification mode by at least 5%, at least 10%, at least 20%, or at least 50%. The flow direction in preparation mode can be opposite to that in humidification mode. In other words, in preparation mode, breathing air can be inhaled rather than blown out at the breathing air outlet as in humidification mode. In this way, it can be prevented that breathing air that is, in some cases, excessively warm and / or excessively humid can be inhaled by the patient.

[0044] According to one embodiment, the operation of a respiratory air humidifier in preparation mode may include generating a control signal to control at least one electro-pneumatic actuator such that the volumetric flow rate of the respiratory air provided at the respiratory air outlet follows a volumetric flow rate transition in which the volumetric flow rate increases partially or continuously, and / or the pressure of the respiratory air provided at the respiratory air outlet follows a pressure transition in which the volumetric flow rate of the respiratory air provided at the respiratory air outlet increases partially or continuously. In other words, in preparation mode, the volumetric flow rate or pressure, or both, can be slowed down and increased, for example, in stages. Such (at least partially) increasing transitions allow the patient to promptly remove the mask or nasal cannula connected to the respiratory air outlet if the respiratory air from the mask or nasal cannula feels uncomfortablely warm and / or uncomfortablely humid during inhalation. In contrast, in humidification mode, one or more electromagnetic actuators can be controlled so that, for example, the volumetric flow rate and / or pressure transitions remain constant.

[0045] For example, when restarting high-flow therapy, a reduced respiratory air flow rate can be initially provided at the respiratory air outlet. To this end, a corresponding fan can be restarted, especially at a low speed, and the resulting respiratory airflow is maintained at a rate lower than the actual flow rate intended for high-flow therapy for an appropriate period of time. In this case, the inhaled air mixture does not exceed the critical temperature by mixing the respiratory air with ambient air at each patient interface.

[0046] According to one embodiment, the operation of a breathing air humidifier in preparation mode may include generating a control signal for controlling at least one electro-pneumatic actuator, thereby ensuring that the volumetric flow rate of breathing air provided at the breathing air outlet reaches a final value at the end of the preparation mode operation of the breathing air humidifier that is less than or equal to a target volumetric flow rate that the breathing air humidifier should have at the start of the next operation in humidification mode. For example, in preparation mode, the volumetric flow rate may be gradually increased to the target volumetric flow rate, or to a value slightly less than the target volumetric flow rate (e.g., up to 10% or up to 5%). This avoids volumetric flow rate fluctuations that may be unpleasant when switching from preparation mode to humidification mode.

[0047] According to one embodiment, the operation of a breathing air humidifier in preparation mode may include generating a control signal for controlling at least one electro-pneumatic actuator, thereby ensuring that the pressure of the breathing air provided at the breathing air outlet reaches a final value at the end of the breathing air humidifier's preparation mode operation that is less than or equal to a target pressure value that the breathing air humidifier should have at the start of the next operation in humidification mode. For example, in preparation mode, the pressure can be gradually increased to a target pressure value, or to a value slightly less than the target pressure value (e.g., up to 10% or up to 5%). This avoids pressure fluctuations that may be uncomfortable when switching from preparation mode to humidification mode.

[0048] According to one embodiment, the respiratory air humidifier may further include a respiratory hose for connection to a respiratory air outlet, which is heated by an electric hose heater. The respiratory hose can be connected to the respiratory air outlet while the respiratory air humidifier is operational. The respiratory air humidifier may further be designed to additionally temperature-regulate the respiratory air flowing through the respiratory hose by the hose heater in humidification mode. This prevents, for example, the respiratory air from being excessively cooled as it passes from the respiratory air outlet in the respiratory hose to the respiratory apparatus of the patient being ventilated. In this case, the method may further include disabling the operation of the hose heater while the respiratory air humidifier is operating in preparation mode. In this way, it is possible to avoid further undesirable heating of the respiratory air flowing through the respiratory hose in preparation mode, which may already be uncomfortably humid and / or uncomfortably warm.

[0049] According to one embodiment, a warning message can be generated to alert the user of the respiratory air humidifier when the respiratory air humidifier is switched to a ready mode. The warning message can be, for example, a visual, auditory, and / or tactile message. The warning message can be displayed via the respiratory air humidifier itself and / or via peripheral devices connected to the respiratory air humidifier wirelessly and / or via wired data communication (e.g., via the Internet). Such peripheral devices may be, for example, medical engineering equipment (particularly ventilators), smartphones, smartwatches, tablets, laptops, or PCs. For example, the warning message can be used to prompt the user to remove the mask or nasal cannula connected to the respiratory air outlet, thereby avoiding contact between the user's airway and respiratory air that may be excessively warm and / or excessively humid.

[0050] According to one embodiment, the heating element can be prevented from operating while the breathing air humidifier is operating in preparation mode. To achieve this, the heating element can be disconnected from the power supply, for example, by a separate switch. This prevents, for example, the heating element from accidentally operating while the breathing air humidifier is operating in preparation mode.

[0051] According to one embodiment, a breathing air humidifier may further comprise a breathing air passage for guiding breathing air between a breathing air inlet and a breathing air outlet, and a container for storing a liquid, such as water or a liquid containing water, for humidifying the breathing air. In this case, a heating element may be designed to heat the liquid from the container. Thus, the breathing air humidifier can be designed so that the breathing air comes into contact with the liquid in an evaporated and / or heated state as it flows through the breathing air passage. This allows the breathing air to be humidified before it flows out at the breathing air outlet.

[0052] Furthermore, the respiratory air humidifier may be equipped with one or more electro-pneumatic actuators for controlling the respiratory airflow through the respiratory air passage.

[0053] Embodiments of the present invention will be described below with reference to the accompanying drawings. Neither the description nor the drawings should be understood as limiting the scope of the present invention. [Brief explanation of the drawing]

[0054] [Figure 1] This figure shows a respiratory air humidifier according to one embodiment of the present invention. [Figure 2] This is a flowchart of the method according to one embodiment of the present invention. [Modes for carrying out the invention]

[0055] The diagrams are purely schematic and not to scale. Where the same reference numerals are used in different drawings, these reference numerals represent the same or the same functional features.

[0056] Figure 1 shows a respiratory air humidifier 1 used in combination with a ventilator. In this example, the respiratory air humidifier 1 comprises a respiratory air inlet 3 to which the ventilator is connected, thereby allowing respiratory air to flow from the ventilator into the respiratory air humidifier 1; a respiratory air outlet 5; a respiratory air passage 7 for guiding respiratory air between the respiratory air inlet 3 and the respiratory air outlet 5; a container 8 for storing a liquid (e.g., water or a liquid containing water) for humidifying the respiratory air; and an electric heating element 9 for heating the liquid from the container 8. The respiratory air humidifier 1 is designed so that as the respiratory air flows from the respiratory air inlet 3 through the respiratory air passage 7 to the respiratory air outlet 5, it comes into contact with the vaporized and heated liquid, thereby humidifying (and temperature-regulating) the respiratory air before it flows out at the respiratory air outlet 5. During humidification, for example, by appropriately controlling the heating element 9, the respiratory air can be brought to a specific comfort temperature that feels comfortably warm when inhaled. The respiratory air outlet 5 can be connected to the patient's respiratory device via one or more respiratory hoses and / or a suitable patient interface such as a respiratory mask, nasal cannula, or tube, thereby ventilating the patient with respiratory air from the respiratory air humidifier 1.

[0057] Furthermore, the respiratory air humidifier 1 may include at least one electro-pneumatic actuator 11 for controlling the respiratory airflow 13 through the respiratory air passage 7. The actuator 11 may be, for example, a blower and / or an electrically controllable valve. It is possible to place the actuator 11 (or at least one of the actuators 11) within the housing of the respiratory air humidifier. However, it is also possible to place the actuator 11 (or at least one of the actuators 11) within the housing of the ventilator.

[0058] Furthermore, the respiratory air humidifier 1 includes a control unit 15 for controlling the operation of the respiratory air humidifier 1. The control unit 15 can be designed as a component of the respiratory air humidifier 1 and / or placed within the housing of the respiratory air humidifier 1. However, the control unit 15 can also be designed as a component of a ventilator and / or placed within the housing of the ventilator.

[0059] The control unit 15 can be configured to switch the respiratory air humidifier 1 between a humidification mode and a preparation mode for preparing the respiratory air humidifier 1 for operation in humidification mode. The respiratory air humidifier 1 can be designed to humidify the respiratory air supplied via a ventilator at the respiratory air inlet 3 in humidification mode, and to provide the humidified air as a respiratory airflow 13 at the respiratory air outlet 5 by appropriately controlling, for example, actuator 11 (or a plurality of actuators 11).

[0060] The control unit 15 may include, for example, a processor 17 and a storage device 19 in which a computer program for operating the respiratory air humidifier 1 can be stored. The processor 17 may be configured to execute the following method M (see Figure 2) by executing the computer program.

[0061] In the first step S1, if the patient interrupts or wishes to interrupt ventilation therapy for any reason (e.g., for a duration of 30 seconds to 3 minutes), the on or off of the respiratory air humidifier 1, for example, by manual on or off, is recognized.

[0062] In response to the on or off recognition in step S1, in step S2, the breathing air humidifier 1 is switched to a ready mode and operates in the ready mode for a specific duration of operation, thereby actively and / or passively discharging excess heat from inside the breathing air humidifier 1, for example, through the breathing air passage 7, based on the operation of the breathing air humidifier 1 in humidification mode prior to the on or off.

[0063] If the breathing air humidifier 1 is detected as being turned on in step S1, the (turned-on) breathing air humidifier 1 will automatically switch to humidification mode immediately after operation in preparation mode in step S3, for example, and can operate in humidification mode until the breathing air humidifier 1 is turned off again. After the end of preparation mode, it is also conceivable that the breathing air humidifier 1 and / or the ventilator may prompt each user to switch the breathing air humidifier 1 to humidification mode by generating appropriate auditory and / or visual and / or tactile operational messages.

[0064] If the respiratory air humidifier 1 is turned off in step S1, the (turned-off) respiratory air humidifier 1 may remain turned off without any further reaction following its operation in the ready mode. That is, even if the respiratory air humidifier 1 is turned off, it may still be able to operate in the ready mode for a certain duration of operation immediately after being turned off, for example, to allow sufficient cooling of the respiratory air humidifier 1 before it is turned on again (manually) so that the patient may want to resume ventilation therapy, and / or to accelerate the cooling of the respiratory air humidifier 1.

[0065] Purposefully, the respiratory air humidifier 1 may be equipped with an additional battery to supply power to the respiratory air humidifier 1 when it is turned off, for example, when operating in preparation mode. The additional battery may be, for example, rechargeable. In this case, the respiratory air humidifier 1 can be designed to charge the additional battery when it is turned on, for example, when operating in preparation mode and / or humidification mode. In this way, it is possible to ensure that the battery is fully charged each time the respiratory air humidifier 1 is turned off.

[0066] The breathing air humidifier 1 can be switched to a ready mode (first) each time it is turned on or off. In this case, the breathing air humidifier 1 can be operated in ready mode for a fixed, specified operating duration, for example, preferably 30 seconds to 5 minutes.

[0067] Alternatively, in step S2, the switch to the preparation mode can be performed in a temperature-dependent manner. Furthermore, the duration of operation of the breathing air humidifier 1 in the preparation mode can be controlled in a temperature-dependent manner.

[0068] For this purpose, in an optional step S4, the control unit 15 can receive a temperature value indicating the current temperature of the breathing air inside the breathing air humidifier 1, for example, in the breathing air passage 7, as a response to the on or off recognition in step S1. The temperature value can be measured and / or estimated.

[0069] Next, in step S5, the temperature value can be compared to a specific threshold. The threshold indicates the temperature threshold at which breathing air feels comfortable when inhaled. The threshold can be stored, for example, in a storage device 19. The threshold may be fixed or configurable by each user via an appropriate user interface.

[0070] If the comparison in step S5 results in the temperature value exceeding the threshold, that is, if the current temperature exceeds the temperature threshold, the breathing air humidifier 1 can be switched to preparation mode in step S2 and operated in preparation mode.

[0071] In contrast, if the comparison in step S5 results in the temperature value not exceeding a threshold, that is, the current temperature is either equal to or below the temperature threshold, it is possible to prevent switching to the preparation mode. Instead, the breathing air humidifier 1 can be switched to humidification mode immediately after being turned on, for example in step S3, and preferably operate in humidification mode until the breathing air humidifier 1 is turned off again.

[0072] Following the on / off detection in step S1, temperature values ​​can be received in multiple consecutive time steps in step S4. In this case, in step S5, the temperature value of each time step can be compared with a threshold. This enables temperature-dependent control of the duration of operation in preparation mode, as operation in preparation mode automatically terminates as soon as the temperature value no longer exceeds the threshold. For example, a (turned-on) breathing air humidifier 1 can be automatically switched from preparation mode to humidification mode as soon as the temperature value no longer exceeds the threshold.

[0073] The temperature value can preferably be merely an estimate. This has the advantage of eliminating the need for a separate temperature sensor to detect the current temperature inside the breathing air humidifier 1, for example, in the breathing air passage 7, thereby reducing manufacturing costs.

[0074] For example, in an additional step S6, the temperature value can be calculated using a suitable mathematical model that approximately represents the specific physical characteristics of the breathing air humidifier. To this end, the control unit 15 can receive at least one measured and / or estimated input value and input it into the mathematical model. The mathematical model can be configured to convert at least one input value into a corresponding temperature value and output that temperature value as an output value. The output value can then be further processed in an appropriate manner by the control unit 15.

[0075] The input values ​​are, for example, the following variables, i.e. -Current heating output of heating element 9, -Current filling level of container 8, - The (e.g., average) duration of at least one heating phase in which the heating element 9 was operating, prior to turning it on or off. - The (e.g., average) duration of at least one cooling phase in which the heating element 9 was inactive, prior to turning it on or off. -Current ambient temperature in the surrounding environment of the breathing air humidifier 1, -Current relative air humidity with respect to current ambient temperature in the surrounding environment of respiratory air humidifier 1, - Current ambient pressure in the surrounding environment of the breathing air humidifier 1 One of these can be defined.

[0076] To calculate the temperature value, it is possible to input multiple input values ​​for at least two different variables, such as at least two of the variables mentioned above, into the mathematical model simultaneously.

[0077] The mathematical model can be stored in the memory device 19, for example, in the form of mathematical functions and / or lookup tables. For example, the parameters of the mathematical model can be verified experimentally.

[0078] The operation of the respiratory air humidifier 1 in preparation mode can also be restricted to preventing the respiratory air humidifier 1 from switching to humidification mode and / or preventing the heating element 9 from operating. This allows for controlled passive heat dissipation.

[0079] Additionally or alternatively, controlled active heat dissipation is possible. For this purpose, the control unit 15 can generate one or more control signals 21 for controlling the actuator 11 (or a plurality of actuators 11) during operation in the preparation mode of the breathing air humidifier 1, for example.

[0080] The actuator 11 (or multiple actuators 11) can be controlled by the control signal 21 (or multiple control signals 21) as follows, for example. - A breathing airflow 13 for expelling excess heat is generated through the breathing air inlet 3 and / or through the breathing air outlet 5 and / or through at least one vent of the breathing air humidifier 1 separated from the breathing air inlet 3 and the breathing air outlet 5. - The provision of breathing air at the breathing air outlet 5 is prevented. - The breathing air is supplied at the breathing air outlet 5 at a lower pressure and / or lower volumetric flow rate and / or a different flow direction than when the breathing air humidifier 1 is operating in humidification mode. - The volumetric flow rate of breathing air provided at the breathing air outlet 5 follows a volumetric flow rate progression that increases at least partially. - The pressure of the breathing air provided at the breathing air outlet 5 follows a pressure transition that increases at least partially. - The volumetric flow rate of breathing air provided at the breathing air outlet 5 reaches a final value at the end of operation in the preparation mode of the breathing air humidifier 1 that is the same as, or only slightly (e.g., up to 10% or up to 5%) lower than, the volumetric flow rate target value that the breathing air humidifier 1 should have at the start of the next operation in the humidification mode. - The pressure of the breathing air provided at the breathing air outlet 5 reaches a final value at the end of the breathing air humidifier 1's preparation mode operation that is the same as, or only slightly (e.g., up to 10% or up to 5%) lower than, the pressure that should be at the start of the next operation of the breathing air humidifier 1 in humidification mode.

[0081] The controllability listed above can be implemented individually or in combination, and at least two of the listed controllability can be combined with each other.

[0082] Furthermore, in step S2, appropriate warning messages can be generated to alert each user, for example, if the breathing air feels excessively moist and / or excessively warm upon inhalation. The warning messages may also prompt each user to take specific actions, such as waiting for the breathing air to cool sufficiently and / or removing the breathing mask or nasal cannula.

[0083] The breathing hose (or multiple breathing hoses connected to the breathing air outlet 5) connected to the breathing air outlet 5 may optionally be intentionally heated by an electric hose heater. In this case, the breathing air humidifier 1, for example, the control unit 15, can be designed to additionally temperature-regulate the breathing air flowing through the breathing hose (or multiple breathing hoses) by controlling the hose heater in humidification mode. Thus, method M may include an additional step in which the operation of the hose heater is prohibited while the breathing air humidifier 1 is operating in preparation mode. In this way, it is possible to avoid undesirable further heating of the breathing air flowing through the breathing hose (or multiple breathing hoses), which may already be excessively humid and / or excessively warm, in preparation mode.

[0084] Finally, it should be noted that terms such as "have," "equip," "include," and "with" do not exclude other elements or steps, and the singular indefinite article does not exclude the plural.

[0085] Furthermore, it should be noted that any feature or step described with reference to one of the above embodiments may be used in combination with any feature or step described with reference to another of the above embodiments.

[0086] The reference numerals in the claims should not be understood as limiting the scope of the subject matter defined by the claims. [Explanation of Symbols]

[0087] 1. Respiratory air humidifier 3. Breathing air inlet 5. Breathing air outlet 7. Breathing air passage 8 containers 9 Electric heating element 11 Electro-pneumatic actuator 13. Breathing airflow 15 Control Unit 17 Processors 19 Storage device 21 Control signals M method S1 On or Off Recognition Switching to S2 preparation mode Switching to S3 humidification mode S4 Receiving temperature values Comparison of S5 temperature values S6 Calculation of temperature value

Claims

1. A method (M) for operating a respiratory air humidifier (1), The breathing air humidifier (1) comprises a breathing air inlet (3), a breathing air outlet (5), and an electric heating element (9), and is switchable between a humidification mode and a preparation mode for preparing the breathing air humidifier (1) for operation in the humidification mode, and is designed to humidify breathing air supplied to the breathing air inlet (3) and temperature-controlled by the heating element (9), and to provide the humidified breathing air to the breathing air outlet (5), A method comprising the steps of switching the breathing air humidifier (1) to the preparation mode (S2) and operating the breathing air humidifier (1) in the preparation mode, so that when the breathing air humidifier (1) is turned on or off, excess heat resulting from the operation of the breathing air humidifier (1) in the humidification mode prior to the turning on or off can be discharged from inside the breathing air humidifier (1), wherein the heating element (9) is deactivated in the preparation mode.

2. When the aforementioned respiratory air humidifier (1) is turned on, The method according to claim 1, further comprising the steps of switching the breathing air humidifier (1) to the humidification mode (S3) following the operation of the breathing air humidifier (1) in the preparation mode, and operating the breathing air humidifier (1) in the humidification mode.

3. When the respiratory air humidifier (1) is turned on or off, Step (S4) of receiving a temperature value indicating the current temperature of the breathing air inside the breathing air humidifier (1), Step (S5) involves comparing the temperature value with a threshold value indicating the temperature threshold at which the breathing air feels comfortable during inhalation, and The method according to claim 1 or 2, further comprising the steps of switching the breathing air humidifier (1) to the preparation mode (S2) when the temperature value exceeds the threshold, and operating the breathing air humidifier (1) in the preparation mode.

4. When the aforementioned respiratory air humidifier (1) is turned on, The method according to claim 3, further comprising the steps of switching the breathing air humidifier (1) to the humidification mode (S3) if the temperature value does not exceed the threshold, and operating the breathing air humidifier (1) in the humidification mode.

5. The method according to claim 3 or 4, wherein the temperature value is received in a plurality of consecutive time steps, compared with the threshold in each time step, and the breathing air humidifier (1) is operated in the preparation mode until the temperature value falls below the threshold in one of the time steps.

6. Step (S6) of calculating the temperature value using a mathematical model of the breathing air humidifier (1), wherein at least one input value is received and input to the mathematical model, the mathematical model converts the at least one input value into the temperature value and outputs the temperature value as an output value, and the at least one input value is, The heating output of the heating element (9), The filling level of the container (8) for storing the liquid used to humidify the breathing air, The duration of at least one heating phase in which the heating element (9) was operating, prior to the aforementioned on or off, The duration of at least one cooling phase in which the heating element (9) was inactive, prior to the aforementioned on or off, The ambient temperature in the surrounding environment of the aforementioned breathing air humidifier (1), The relative air humidity of the surrounding environment of the aforementioned breathing air humidifier (1) with respect to the ambient temperature, Ambient pressure in the surrounding environment of the breathing air humidifier (1) The further step includes demonstrating at least one of the following: The method according to any one of claims 3 to 5.

7. The operation of the respiratory air humidifier (1) in the preparation mode is as follows: This includes generating a control signal (21) for controlling at least one electro-pneumatic actuator (11) to generate an airflow (13) for discharging the excess heat through the breathing air inlet (3) and / or the breathing air outlet (5) and / or at least one vent of the breathing air humidifier (1) separated from the breathing air inlet (3) and the breathing air outlet (5), The method according to any one of claims 1 to 6.

8. The operation of the respiratory air humidifier (1) in the preparation mode is as follows: To prevent the breathing air from being supplied at the breathing air outlet (5), a control signal (21) is generated to control at least one electro-pneumatic actuator (11), and / or This includes generating a control signal (21) for controlling at least one electro-pneumatic actuator (11) to provide the breathing air at the breathing air outlet (5) at a lower pressure and / or lower volumetric flow rate and / or a different flow direction than when the breathing air humidifier (1) is operating in the humidification mode, The method according to any one of claims 1 to 7.

9. The operation of the respiratory air humidifier (1) in the preparation mode is as follows: The method includes generating a control signal (21) for controlling at least one electro-pneumatic actuator (11) such that the volumetric flow rate of the breathing air provided at the breathing air outlet (5) follows a volumetric flow rate transition in which the volumetric flow rate of the breathing air provided at the breathing air outlet (5) increases at least partially, and / or the pressure of the breathing air provided at the breathing air outlet (5) follows a pressure transition in which the pressure of the breathing air is increased at least partially. The method according to any one of claims 1 to 8.

10. The operation of the respiratory air humidifier (1) in the preparation mode is as follows: A control signal (21) is generated to control at least one electro-pneumatic actuator (11), thereby ensuring that the volumetric flow rate of the breathing air provided at the breathing air outlet (5) reaches a final value at the end of the operation of the breathing air humidifier (1) in the preparation mode that is less than or equal to the volumetric flow rate target value that the breathing air humidifier (1) should have at the start of the next operation in the humidification mode, and / or The method includes generating a control signal (21) for controlling at least one electro-pneumatic actuator (11), thereby ensuring that the pressure of the breathing air provided at the breathing air outlet (5) reaches a final value at the end of the operation of the breathing air humidifier (1) in the preparation mode, such that the pressure is less than or equal to a target pressure value that the breathing air humidifier (1) should have at the start of the next operation in the humidification mode. The method according to any one of claims 1 to 9.

11. The breathing air humidifier (1) further comprises a breathing hose that can be heated by an electric hose heater and connected to the breathing air outlet (5), The method (M) further includes prohibiting the operation of the hose heater while the breathing air humidifier (1) is operating in the preparation mode. The method according to any one of claims 1 to 10.

12. A control unit (15) configured to perform the method (M) described in any one of claims 1 to 11.

13. A breathing air humidifier (1) comprising a breathing air inlet (3), a breathing air outlet (5), an electric heating element (9), and a control unit (15) according to claim 12, wherein the breathing air humidifier (1) is switchable between a humidification mode and a preparation mode for preparing the breathing air humidifier (1) for operation in the humidification mode, and is designed in the humidification mode to humidify breathing air supplied at the breathing air inlet (3) and whose temperature is controlled by the heating element (9), and to provide the breathing air in the humidified state at the breathing air outlet (5).

14. A computer program that, when executed by the control unit (15) described in claim 12, includes an instruction to cause the control unit (15) to execute the method (M) described in any one of claims 1 to 11.

15. A computer-readable medium having the computer program described in claim 14 stored on it.

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