Device and method for generating a pre-pressure at a regulating valve of a

Abstract

The invention relates to a device for generating a prepressure at a regulating valve of a breathing machine, comprising a blower (1), a control unit (2) and a regulating valve (3). The blower (1) is designed to draw in ambient air through an inlet, compress the ambient air and transmit the compressed air to the control valve (3). The control unit (2) is designed to vary the rotational speed of the blower (1). The device is characterized in that the control unit (2) is further designed to operate the blower (1) at a first rotational speed level (n1) and to determine a trigger time (t0) at which the rotational speed of the blower (1) is temporarily changed from the first rotational speed level (n1) to a second rotational speed level (n2) within the same breathing cycle of the breathing machine, wherein the first rotational speed level (n1) is smaller than the second rotational speed level (n2). The invention further relates to a method for generating a prepressure on a control valve (3), a respirator and a computer program product.

Description

Technical Field

[0001] This invention relates to an apparatus and method for generating pre-pressure at the regulating valve of a ventilator. Furthermore, this invention relates to a ventilator having such an apparatus and a computer program product including instructions that cause a control unit to implement this method. Background Technology

[0002] A ventilator is used to assist or take over a patient's breathing. The purpose is to supply the patient with adequate oxygen and to promote the removal of carbon dioxide from the lungs. This is achieved by supplying the patient with a respiratory airflow, the characteristics of which, in particular, pressure, volumetric flow rate, and oxygen concentration, can be modified by the ventilator.

[0003] Ventilators typically include a regulating valve that allows for the customizable setting of respiratory airflow characteristics, particularly pressure and volumetric flow rate, for supplying air to a patient. The respiratory airflow typically comprises air, which may be obtained from a central air supply in the hospital. Alternatively, ventilators are known to utilize ambient air to form the respiratory airflow. These ventilators include a blower that draws in ambient air, compresses it, and delivers it through the regulating valve to a patient interface, which may include, for example, a breathing mask. Additionally, oxygen, for example, also from a central air supply or from a cylinder, may be mixed into the ambient air, if necessary for ventilating the patient.

[0004] The blower includes an electric motor, which is typically controlled by the ventilator's control unit, and the speed of the motor or blower is settable. Speed ​​here corresponds to revolutions per second (rpm). The pressure generated by the blower is essentially related to its speed. When ambient air is delivered or supplied to the patient interface through the blower and regulating valves—that is, when a mass flow is generated—the pressure drops at the blower outlet, particularly due to constraints in the flow path. To maintain pressure, the blower should be fine-tuned or regulated in this situation.

[0005] Essentially, two common alternative operating variants of blowers are dynamic and static operation. Dynamic operation requires a rapid response behavior. For example, a dynamic blower can generate a 50 mbar pressure increase within 100 ms. Correspondingly, a dynamic blower must include an electric motor adapted to achieve the corresponding speed increase in a short time. Such a dynamic blower allows for flexible pressure changes throughout the entire respiratory cycle of the ventilator, particularly with almost continuous speed and thus pressure adaptation.

[0006] Compared to dynamically operating blowers, statically operating blowers exhibit significantly slower response behavior. For example, a statically operating blower requires approximately 200 ms to raise the pressure to 50 mbar. This is typically too slow for flexibly setting the pressure of the respiratory airflow. Therefore, it is usually necessary to operate the blower at a fixed speed throughout the respiratory cycle, so that the corresponding pressure is generated by the statically operating blower during the respiratory cycle, especially during the inspiratory phase.

[0007] Compared to dynamically operating blowers, statically operating blowers have the following advantages: They are less expensive to use. On the one hand, they are cheaper to manufacture; on the other hand, they experience less wear and require less energy.

[0008] The problem with using a statically operated blower is that the pressure in the respiratory system drops due to changes in flow parameters during ventilation, particularly volumetric flow rate, or when mass flow is generated when the regulating valve is opened, and the statically operated blower does not compensate for these pressure fluctuations. Therefore, it is impossible, or only possible to a limited extent, to provide the patient with the optimal supply of respiratory airflow and corresponding pressure that meets their needs.

[0009] This problem is solved in practice by operating the static blower at a speed higher than the pressure required for the respiratory flow to be provided and set at the ventilator. Therefore, the pressure generated by the static blower, operated in this way, is sufficiently high that the pressure set by the operator at the ventilator can be achieved during the delivery of respiratory flow to the patient via the regulating valve, without pressure fluctuations or only insignificant pressure fluctuations, i.e., remaining substantially constant.

[0010] The difference between the set pressure and the higher pressure provided by the statically running blower is called the pressure regulation margin (Druck-Regelreserve). Therefore, in this case, the pressure generated by the statically running blower is higher than the pressure set at the ventilator. A regulating valve arranged along the flow direction after the blower ensures that the pressure of the respiratory airflow corresponds to the set pressure.

[0011] A disadvantage of pressure regulation margin is the additional energy required to generate higher pressures. Furthermore, when generating this higher pressure at higher speeds, the statically operating blower produces more noise that can be disruptive to patients and causes greater wear. Therefore, it is advantageous to keep the statically operating blower's pressure regulation margin as low as possible.

[0012] In the prior art, a method for adjusting pressure regulation margin after a respiratory cycle is known from DE10023656C1. Here, during or after delivering a respiratory flow to the patient, the pressure provided by a statically running blower is evaluated as too high or too low for a respiratory cycle based on the opening state of an additional bypass valve, wherein the pressure regulation margin of the statically running blower and thus the speed are adjusted for the next respiratory cycle based on this evaluation. Summary of the Invention

[0013] Based on solutions known from the prior art and the problems previously described, the objective of this invention is to create a low-cost and improved device for generating pre-pressure at the regulating valve of a ventilator, wherein the pre-pressure should be substantially constant during the respiratory cycle of the ventilator.

[0014] The aforementioned task is accomplished by an apparatus for generating prepressure at the regulating valve of a ventilator having the features of claim 1, a method for generating prepressure at the regulating valve of a ventilator according to claim 9, a ventilator according to claim 8, and a computer program product according to claim 10. Further details of the invention are derived from the dependent claims, the specification, and the drawings. The features and details described herein, in conjunction with the apparatus, also apply to the method, the ventilator, and the computer program product, such that disclosures relating to various aspects of the invention are always mutually referenced or, more precisely, mutually referential.

[0015] The device according to the invention for generating pre-pressure at the regulating valve of a ventilator includes a blower, a control unit, and a regulating valve. Here, the blower is designed to draw in ambient air through an inlet, compress the ambient air, and transmit it to the regulating valve. The control unit is configured to change the speed of the blower, and thus affect the pressure and volumetric flow rate of the inhaled ambient air. The device according to the invention is characterized in that the control unit is further configured to operate the blower at a first speed level, and specifically to determine a triggering time point by evaluating available data, at which the speed of the blower is temporarily changed from the first speed level to a second speed level within the same respiratory cycle of the ventilator. Here, the first speed level is lower than the second speed level.

[0016] As previously described, a ventilator is used to assist or take over the patient's work of breathing. Anesthesia devices can also provide this function, wherein the anesthesia device includes at least components of a ventilator. In the context of this invention, the term "ventilator" can be understood not only as a ventilator but also as an anesthesia device with ventilation function.

[0017] In a ventilator equipped with a device according to an embodiment of the invention, a blower, particularly a radial blower, is fluidly connected to the ventilator's inlet and regulating valve, and its rotational speed can be changed by a control unit. Here, the control unit preferably changes the blower's rotational speed by adapting a control voltage applied to the blower and preferably proportional to the rotational speed. It is also conceivable that the control unit transmits analog or digital control signals to the blower via wired or wireless means, wherein the control signals include information describing the blower's rotational speed. The control unit is preferably designed as a microprocessor. Furthermore, it is conceivable that the control unit is designed as a FPGA (Field Programmable Gate Array), ASIC (Application-Specific Integrated Circuit), or a comparable component for data processing and control.

[0018] According to the invention, the blower can operate statically, wherein the rotational speed is at least temporarily constant during the respiratory cycle of the ventilator. The respiratory cycle of the ventilator herein includes an inspiratory phase and an expiratory phase.

[0019] During the inspiratory phase, the ventilator directs breathing gas to the patient. A regulating valve is at least partially open during this phase, and at least a portion of the ambient air drawn in by the blower is delivered as a breathing gas flow to the ventilator's outlet. The outlet is preferably fluidly connected to the patient interface for supplying the patient with a breathing gas flow.

[0020] During the expiratory phase, the regulating valve is at least partially closed, and no or only a small portion of the respiratory airflow is directed to the patient. During expiration, a small portion of the respiratory airflow is typically generated at the ventilator outlet to achieve what is known as PEEP (Positive End-Expiratory Pressure).

[0021] When a ventilator takes over a patient's work of breathing, the duration of the inspiratory and expiratory phases is typically pre-defined by the ventilator user and can be set on the ventilator. In contrast, when a ventilator assists a patient's work of breathing, the duration of the inspiratory and expiratory phases is typically related to the patient's respiratory effort (Atemanstrengung), which can be detected by the ventilator. Respiratory effort, i.e., the patient's at least partial inhalation and / or exhalation, can be detected here using suitable sensors on the ventilator.

[0022] The control unit is configured to determine the triggering time. Here, the triggering time is preferably the point within the respiratory cycle at or shortly before which the regulating valve is at least partially open and provides respiratory airflow, i.e., the inspiratory or delivery phase of the ventilator during the respiratory cycle. The triggering time is preferably shortly before the start of the delivery phase, for example, in the range of 100 to 500 ms. Particularly preferably, the triggering time is up to one second before the start of the delivery phase. Specifically, the triggering time being shortly before the delivery phase ensures that the blower actually reaches the second speed level at least at the start of the delivery phase.

[0023] The trigger time point is preferably derived from at least one setting of the ventilator and / or can be determined by monitoring the patient's respiratory effort using suitable sensors and / or control units of the ventilator. Furthermore, the trigger time point can preferably be determined from the patient's respiratory effort or from a delivery phase of a previous respiratory cycle.

[0024] The control unit is further configured to operate the blower at a first speed level outside the delivery phase of the ventilator's respiratory cycle, and to abruptly increase the blower speed to a second speed level at a trigger time. This second speed level is preferably set indirectly, at least at the ventilator, and is therefore pre-given and / or determined by the ventilator and / or the control unit.

[0025] As previously described, when the regulating valve is at least partially open, particularly during the delivery phase where a mass flow is present, the pressure supplied by the blower, i.e., the pre-pressure, decreases. This pressure drop results in less ambient air being delivered from the blower to the regulating valve per unit time because the maximum deliverable volumetric flow rate is reduced, and this lasts for a longer period until the required volume of respiratory gas is provided. Consequently, the patient may be supplied with a suboptimal or non-compliant airflow.

[0026] In an advantageous manner, increasing the blower speed to a second speed level during the respiratory cycle results in the following: the respiratory airflow pressure set at the ventilator can be maintained because the pre-pressure at the regulating valve, i.e., the pressure provided by the blower, is at least partially increased briefly at the blower outlet according to the second speed level during the delivery phase, and does not drop below the set pressure even if the pre-pressure decreases during the delivery phase due to the opening of the regulating valve. Therefore, a substantially constant pressure, i.e., the respiratory airflow pressure, can be achieved downstream of the regulating valve along the flow direction.

[0027] The control unit is configured to temporarily change the blower speed during a respiratory cycle, wherein the speed can be increased from a first speed level to a second speed level and can be decreased again during or immediately after the delivery phase. Preferably, the decrease in speed from the second speed level occurs after the delivery phase, which substantially corresponds to the start of the expiratory phase of the ventilator's respiratory cycle. Particularly preferably, the decrease in speed from the second speed level occurs temporally after the start of the delivery phase and before its end, preferably up to two seconds after the start of the delivery phase, and particularly preferably up to one second. This ensures that the second speed level is applied long enough to maintain the pressure set at the ventilator. Accordingly, a pressure regulation margin can be increased for a limited time period within the respiratory cycle, at least during the delivery phase.

[0028] A particular advantage arises from the brief increase in blower speed during the respiratory cycle: the larger second speed level is applied only for a limited time during the respiratory cycle, and therefore less energy is required overall to operate the blower throughout the entire respiratory cycle. By increasing the speed during the respiratory cycle, a pressure drop in the respiratory airflow to be supplied during that cycle can be advantageously avoided, thus enabling a supply that meets the patient's needs.

[0029] Furthermore, the lower initial rotational speed during the breathing cycle results in lower operating noise, lower energy consumption, and less wear on the blower. Simultaneously, the pressure of the breathing airflow remains essentially constant during the delivery phase.

[0030] The blower has advantages: it can be manufactured at low cost and operated with energy efficiency because it does not require rapid changes in speed, and the speed is only increased briefly. The blower is preferably suitable for achieving a pressure rise of 50 mbar (corresponding to 5000 Pa) within a time range of 200 ms to 400 ms. Particularly preferably, the blower is suitable for achieving a pressure rise of 10 mbar (corresponding to 1000 Pa) within a time range of 200 ms to 400 ms. Here, the pressure that the blower can generate is proportional to the blower's rotational speed.

[0031] According to a preferred embodiment of the device, the control unit is configured to change the blower speed from a second speed level to a first speed level during or after the delivery phase of the ventilator. As previously described, the delivery phase is the period within the respiratory cycle during which a respiratory airflow greater than PEEP (Positive End-Expiratory Pressure) is provided at the outlet. The delivery phase here corresponds to the inspiratory phase during beatmung of the patient.

[0032] Because the first speed level is smaller than the second speed level, the blower operates relatively quietly over long periods and experiences less wear. Furthermore, less energy is required to operate the blower, which is particularly advantageous for battery-powered ventilators, as these devices can operate for extended periods without an external power supply.

[0033] In a preferred embodiment of the device, a control unit is configured to determine a first speed level and a second speed level based on a predetermined pressure value and / or a predetermined volumetric flow rate value. Here, at least the second speed level is above the blower speed equivalent to the predetermined pressure value, so as to compensate for pressure drops during the delivery phase. The predetermined pressure value and / or predetermined volumetric flow rate value are preferably set at the ventilator, i.e., the setting determines the characteristics of the respiratory airflow to be provided.

[0034] The control unit preferably determines a second rotational speed level such that the pressure of the breathing airflow during the delivery phase corresponds to a predetermined pressure value. Here, it calculates the pressure drop formed during the delivery phase with a breathing airflow having a predetermined volumetric flow rate. The second pressure level can be determined by the sum of the determined pressure drop and the predetermined pressure value.

[0035] The control unit is further configured to determine a first speed level such that the first speed level is smaller than a second speed level by a predetermined percentage. The first speed level is preferably 5% to 15%, more preferably 15% to 20%, lower than the second speed level. Furthermore, the first speed level is preferably smaller than the second speed level by a predetermined pressure constant, wherein the speed constant is related to the corresponding blower. The pressure achievable at the first speed level is preferably 5 mbar to 30 mbar (corresponding to 500 Pa to 3000 Pa) lower than the pressure achievable at the second speed level.

[0036] The first and second rotational speed levels can be advantageously determined based on the predetermined characteristics of the respiratory airflow, taking into account the corresponding settings at the ventilator. Therefore, the first and second rotational speed levels can also be adapted to changes in the corresponding settings at the ventilator.

[0037] According to a preferred embodiment of the device, a control unit is configured to determine a trigger point based on at least one ventilation parameter of the ventilator during operation in a first operating mode. The first operating mode herein includes the functionality of the ventilator for forced or controlled ventilation, wherein the ventilator takes over the patient's work of breathing.

[0038] In the first operating mode, the respiratory cycle and its inspiratory and expiratory phases can be set on the ventilator. Specifically, ventilation parameters—respiratory rate, duration of the respiratory cycle, inspiratory time, and / or I:E ratio (the quotient of inspiratory and expiratory time)—are relevant. Therefore, the timing and duration of the inspiratory phase within the respiratory cycle are pre-defined.

[0039] The control unit is configured to, at the latest at a predetermined intake phase time point, preferably earlier, change the blower speed to a second speed level.

[0040] In an advantageous manner, the triggering time point in the first operating mode of the ventilator can be adapted to its settings for the respiratory cycle, wherein the rotational speed can be changed at the time point of the inspiratory or delivery phase.

[0041] In a preferred embodiment of the device, the control unit is configured to determine a trigger point based on the timing of a previous delivery phase of the ventilator during operation in a second operating mode. The second operating mode here includes the functionality of the ventilator to assist the patient's work of breathing, wherein the ventilator determines the inspiratory and expiratory phases of the respiratory cycle based on the patient's respiratory effort detected by the ventilator. This respiratory effort is specifically the patient's spontaneous or involuntary breathing.

[0042] The control unit is preferably configured to: operate the blower horizontally at a second speed as long as a trigger time point has not been determined and / or does not exist, and once a trigger time point has been determined, currently... The blower is then operated horizontally at its first rotation speed.

[0043] In this preferred embodiment, the trigger time point can be determined taking into account the time points of previous transport stages. Here, the control unit can measure the time interval between two previous transport stages and determine the time interval between the two transport stages. The trigger time point is derived based on this time interval, where the trigger time point corresponds to the time point at which the start of the previous transport stage is delayed by this time interval.

[0044] Preferably, multiple time intervals can be determined over multiple respiratory cycles, and an average value can be calculated from them, wherein the trigger time point is derived from the time point at which the start of the previous delivery phase is delayed by the average value.

[0045] Furthermore, the control unit is preferably configured to increment the desired parameter by a constant value within a desired time range and to determine the trigger time point, wherein the trigger time point is reached once the desired parameter has reached the trigger threshold.

[0046] The desired time range is the period from the start of the corresponding respiratory cycle to the trigger point. At the start of the desired time range, the desired parameter can be incremented from zero. Preferably, the desired parameter increments by one per second.

[0047] If the desired parameter reaches or exceeds the trigger threshold, the trigger time point is reached, and the blower speed can be increased to a second speed level. The trigger threshold is preferably pre-defined, and preferably specified to 3 if the desired parameter increases by one per second.

[0048] Particularly preferably, the control unit is configured to increment the desired parameter until the delivery phase of the ventilator begins, and to adapt the trigger threshold if a deviation between the trigger threshold and the desired parameter is determined.

[0049] If the expected parameter is greater than the trigger threshold from the start of the delivery phase, the control unit will reduce the trigger threshold by a pre-given value.

[0050] If the expected parameter is less than the trigger threshold from the start of the delivery phase, the control unit will increase the trigger threshold by a pre-given value.

[0051] If the expected parameters are substantially consistent with the trigger threshold from the start of the delivery phase, the trigger threshold remains valid.

[0052] Advantageously, the triggering time can be determined even in the operating mode of a ventilator with assisted ventilation. Particularly advantageous is the adaptation of the triggering threshold, wherein the triggering time is at least as close as possible to the start of the delivery phase of the ventilator, so that the blower is operated at a higher second speed level only when it is necessary to avoid a drop in the pressure of the respiratory airflow.

[0053] Furthermore, the present invention relates to a ventilator having the device according to the invention or a device according to one of the above embodiments. Due to the only temporary increase in the speed of the blower of the device, the ventilator according to the invention requires less energy to operate, which is particularly advantageous for battery-powered ventilators, thereby providing longer operating times. Another advantage is relatively low operating noise, which operates in a manner that is at least not very disturbing to the patient.

[0054] Furthermore, the present invention relates to a method for generating pre-pressure at the regulating valve of a ventilator, wherein the method is applicable to implementation variations of the previously described device and to ventilators according to the invention, particularly by a control unit. The method according to the invention comprises the following steps:

[0055] - Receive pressure and / or volumetric flow rate values.

[0056] - A first speed level and a second speed level are determined based on pressure and / or volumetric flow rate values, wherein the first speed level is lower than the second speed level.

[0057] - The blower is controlled using a control signal based on the first rotational speed level.

[0058] - Determine the trigger time point,

[0059] - The blower is controlled using a control signal based on the second rotational speed level at the trigger time, with a time delay, and within the same respiratory cycle of the ventilator.

[0060] - The blower is controlled by a control signal to achieve a speed lower than the second speed level.

[0061] First, pressure and / or volumetric flow rate values ​​are received, preferably pre-set by the user of the ventilator. Based on the pre-set values, a first speed level and a second speed level are determined for controlling the blower. Here, the second speed level can be used to achieve a pre-pressure at the inlet of a regulating valve downstream of the blower along the flow direction, said pre-pressure being higher than the pressure to be provided by the regulating valve according to the pre-set values. This results in a pressure regulation margin that enables the regulating valve to generate the required respiratory airflow at its outlet. The first speed level is preferably specified as a value in the range of 5% to 20% lower than the second speed level, such that the blower preferably reaches the second speed level from the first speed level within 200 ms to 400 ms.

[0062] In the next step, the blower is manipulated so that its rotational speed corresponds to a first rotational speed level. Furthermore, a trigger point is determined at which the blower is manipulated to change its rotational speed to a second rotational speed level.

[0063] If the respiratory cycle of the ventilator is pre-defined, the triggering point is preferably shortly before the delivery phase. Particularly preferably, the triggering point is up to one second before the delivery phase, ensuring that a second speed level is present at the blower at the start of the delivery phase.

[0064] If the ventilator is in another operating mode and the respiratory cycle is not pre-defined, the triggering time is determined based on at least one previous delivery phase of the ventilator. Preferably, the triggering time for subsequent respiratory cycles of the ventilator is determined accordingly and adapted as needed.

[0065] Furthermore, during the respiratory cycle of the ventilator, the blower speed is reduced from a second speed level, preferably to a first speed level. The timing of this speed reduction preferably corresponds to the expiratory phase of the ventilator's respiratory cycle, which is pre-defined by the user or determined by the ventilator via suitable sensors. It is also conceivable that the speed be reduced after a pre-defined time following the trigger time, preferably within the range of one to three seconds.

[0066] Furthermore, the present invention relates to a computer program product comprising instructions that, when executed by a control unit, cause the control unit to perform a method for generating pre-pressure at a regulating valve of a ventilator. Here, the ventilator includes a device having a regulating valve, a control unit, and a blower, wherein the blower draws in ambient air through an inlet, compresses it, and delivers it to the regulating valve. The control unit includes a computer, a processor, and / or programmable hardware components, and performs the following steps according to the computer program product:

[0067] - Receive pressure and / or volumetric flow rate values.

[0068] - A first speed level and a second speed level are determined based on pressure and / or volumetric flow rate values, wherein the first speed level is lower than the second speed level.

[0069] - The blower is controlled using a control signal based on the first rotational speed level.

[0070] - Determine the trigger time point,

[0071] -The blower is controlled using a control signal based on the second rotational speed level at the trigger time and with a time delay, and within the same respiratory cycle of the ventilator.

[0072] - The blower is controlled by a control signal to achieve a speed lower than the second speed level. Attached Figure Description

[0073] Further features, objectives, and effects of the invention will become apparent from the following description of specific embodiments and the accompanying drawings. Embodiments of the invention are described, but the general inventive concept is not limited.

[0074] In the diagram:

[0075] Figure 1 The diagram shows the equipment, along with curves of the blower's rotational speed and the volumetric flow rate of the breathing airflow.

[0076] Figure 2 A schematic diagram showing the time curves of rotational speed, prepressure, and volumetric flow rate; and

[0077] Figure 3A simplified schematic diagram of a ventilator with the equipment is shown. Detailed Implementation

[0078] In the following, embodiments of the invention are described in detail with reference to the accompanying drawings.

[0079] Figure 1 A preferred embodiment of the device 10 is shown, which includes a blower 1 and a regulating valve 3 arranged downstream of the blower 1 along the flow direction (indicated by solid arrows). The blower 1 and the regulating valve 3 are fluidly connected. Furthermore, the blower 1 and the regulating valve 3 are electronically connected to a control unit 2, wherein the control unit 2 is configured to at least change the rotational speed N of the blower 1 and the valve opening of the regulating valve 3 (signal and / or transmission paths are shown as dashed lines).

[0080] Control unit 2 is configured to initially operate blower 1 at a first speed horizontally n1, such as in Figure 1 The graph shows a time curve for the rotational speed n(t) of blower 1. When the rotational speed N of blower 1 is greater than zero, blower 1 draws in ambient air, compresses the ambient air, and delivers the ambient air to regulating valve 3. As long as regulating valve 3 is at least partially open, a mass flow with a volumetric flow rate F is formed downstream of regulating valve 3, which is related to the corresponding valve position.

[0081] Furthermore, the control unit 2 is configured to determine the trigger time point t0 and, at the trigger time point t0, operate the blower 1 at a second speed level n2, where the second speed level n2 is greater than the first speed level n1. In this embodiment, the start of the delivery phase t1 is known and pre-defined by the user. The delivery phase t1 is a specified time point at which the control unit 2 manipulates the regulating valve 3 to form a mass flow suitable as a respiratory airflow for supplying the patient during the inspiratory phase of the respiratory cycle. Based on the start of the delivery phase t1, the trigger time point t0 can be determined by the control unit. In this embodiment, the trigger time point t0 is one second prior to the start of the delivery phase t1.

[0082] At the trigger time t0, one second before the start of the delivery phase t1, the control unit 2 changes the speed N of the blower 1 to a second speed level n2. The pre-pressure P applied at the inlet of the regulating valve 3 increases with the increased speed N. The second speed level n2 of the blower 1 and the resulting increased pre-pressure P determine, advantageously ensuring that the decrease in pre-pressure P at the start of the delivery phase t1 has no or only a small effect on the volumetric flow rate F of the respiratory airflow, which is directed to the patient and is represented in the volumetric flow rate-time curve f(t). The relationship between speed N, pre-pressure P, and volumetric flow rate F is discussed in the section on... Figure 2 It is described in more detail in the description.

[0083] The control unit 2 is further configured to operate the blower 1 at a lower speed level than the second speed level n2 at a descent time point t2 after the start of the delivery phase. In this embodiment, the second speed level can be reduced to the first speed level n1 at the descent time point. Here, in this embodiment, the descent time point substantially corresponds to a predetermined expiratory phase of the respiratory cycle. It is also conceivable that the descent time point t2 is located before the start of the expiratory phase. For example, the descent time point t2 is located up to one second after the start of the delivery phase.

[0084] In an advantageous manner, the equipment 10 can be used in an energy-saving way by temporarily changing the rotational speed N, since the blower 1 is operated at an increased rotational speed N, i.e., a second rotational speed level n2, only for a short period of time. In addition, this results in a lower noise load and less wear on the blower 1.

[0085] Figure 2 A schematic diagram showing time curves for various parameters of device 10 is provided. The following time curves are shown: the rotational speed N of blower 1, the pre-pressure P applied to regulating valve 3, and the volumetric flow rate F downstream of regulating valve 3. The correlation between rotational speed N, pre-pressure P, and volumetric flow rate F will be described in more detail below, where time curves 21, 22, and 23 represent at least partially overlapping time ranges, including the trigger time point t0, the start of the conveying phase t1, and the descent time point t2. Furthermore, Figure 2 A comparison is shown between the rotational speed-time curve n(t) of an embodiment of the present invention and the time curve nC(t) of a blower with a constant rotational speed, and the time curves p(t), pC(t), f(t), and fC(t) derived therefrom.

[0086] Firstly, according to Figure 2 The effect of a constant speed level n3 of the blower is described, as can be expected in the case of devices known from the prior art. The speed curve nC(t) with a constant speed n3 over time t results in a substantially constant pre-pressure P until the start of the conveying phase t1. Due to the increased volumetric flow rate F at the start of the conveying phase t1, the pre-pressure P decreases, as shown in the pre-pressure curve 22 and the pre-pressure-time curve pC(t) for the constant speed case. In this case, the decrease in pre-pressure P results in a smaller maximum possible volumetric flow rate F than in the case of a higher pre-pressure P. Therefore, a flatter volumetric flow rate curve fC(t) is obtained, as shown in volumetric flow rate curve 23.

[0087] Compared to the gradual constant-speed volumetric flow rate time curve fC(t), a steeper volumetric flow rate time curve f(t) is obtained when the speed N of blower 1 is temporarily changed at the trigger time point t0 according to the present invention, as shown in volumetric flow rate curve 23. Although the pre-pressure P also decreases, as shown in the pre-pressure curves pC(t), 22, the pre-pressure P remains sufficiently high to achieve a relatively large maximum volumetric flow rate F according to f(t). Therefore, a pre-given volume of mass flow or breathing airflow is advantageously prepared in a shorter time.

[0088] Figure 3 A preferred embodiment is shown in a greatly simplified schematic diagram of a ventilator 30 having device 10, the device including a blower 1 and a regulating valve 3 disposed downstream of the blower, the blower and the regulating valve being electronically connected to a control unit 2. Furthermore, the ventilator 30 includes a volumetric flow sensor 32, an inlet 31, and an outlet 33, wherein the inlet 31 is fluidly connected to the blower 1, and the outlet 33 is fluidly connected to the regulating valve 3. The volumetric flow sensor 32 is disposed downstream of the regulating valve 3 and upstream of the outlet 33, and is used to measure the volumetric flow rate F of the respiratory airflow to be supplied.

[0089] Control unit 2 is configured to set and change the rotational speed N of blower 1 and the valve position of regulating valve 3. When the rotational speed N is greater than zero, the blower draws in ambient air through inlet 31, compresses the ambient air, and delivers it to regulating valve 3, thereby applying a pre-pressure P at regulating valve 3. Once regulating valve 3 is at least partially open, a mass flow is formed through regulating valve 3, which can be used as a respiratory airflow for ventilation of a patient (not shown). Here, the respiratory airflow exits regulating valve 3 in the flow direction. Subsequently, the respiratory airflow is prepared at outlet 33 and can be delivered to the patient through a patient interface (not shown), such as a breathing mask.

[0090] In this embodiment, the respiratory cycle for ventilating the patient is pre-defined, such that the timing of the corresponding delivery phase and expiratory phase is known to the control unit 2. Therefore, the timing of the inspiratory and expiratory phases of the respiratory cycle is known. The inspiratory phase substantially corresponds to the start of the delivery phase t1. Based on the start of the delivery phase t1, the control unit determines a trigger time t0, which indicates when to increase the speed N of the blower 1 from a first speed level n1 to a second speed level n2.

[0091] At a trigger time point t0, up to one second before the start of the delivery phase t1, the blower speed N is increased, resulting in a higher pre-pressure P at regulating valve 3. At the start of the delivery phase t1, regulating valve 3 opens to generate a respiratory airflow. Due to the higher pre-pressure, the predetermined volume of respiratory airflow is quickly prepared and responsibly and efficiently ventilates the patient as needed.

[0092] List of reference numerals

[0093] 1 blower

[0094] 2 control units

[0095] 3 regulating valves

[0096] 10 Equipment

[0097] 21 Speed ​​Curve

[0098] 22 Preload Curve

[0099] 23 Volumetric Flow Rate Curve

[0100] 30 ventilators

[0101] 31 Imports

[0102] 32 Volumetric Flow Sensor

[0103] 33 Discharge outlets

[0104] N blower speed

[0105] n1 First speed level

[0106] n2 Second speed level

[0107] n3 Constant speed level

[0108] n(t) rotational speed-time curve

[0109] Speed-time curve under constant speed nC(t)

[0110] t time

[0111] t0 trigger time point

[0112] t1 transport phase begins

[0113] t2 descent time point

[0114] F is the volumetric flow rate of the respiratory airflow.

[0115] f(t) volumetric flow rate over time curve

[0116] Volumetric flow rate over time under constant rotational speed (fC(t))

[0117] P pre-pressure

[0118] p(t) preload time curve

[0119] pC(t) is the preload time curve under constant rotational speed.

Claims

1. A device (10) for generating a pre-pressure (P) at a regulating valve (3) of a breathing machine (30), the device having a blower (1), a control unit (2) and the regulating valve (3), wherein the blower (1) is designed for taking in ambient air through an inlet (31), compressing the ambient air and delivering it to the regulating valve (3), and wherein the control unit (2) is set up for varying a rotational speed (N) of the blower (1), characterized in that the control unit (2) is in addition set up for operating the blower (1) at a first rotational speed level (n1) and determining a triggering point in time (to) at which the rotational speed (N) of the blower (1) is temporarily changed from the first rotational speed level (n1) to a second rotational speed level (n2) within the same breathing cycle of the breathing machine (30), wherein the first rotational speed level (n1) is smaller than the second rotational speed level (n2). The triggering point in time (to) is located in time before the start of a delivery phase of the breathing machine (30).

2. The apparatus (10) according to claim 1, characterized in that The control unit (2) is set up for changing the rotational speed (N) of the blower (1) from the second rotational speed level (n2) to the first rotational speed level (n1) during or after a delivery phase of the breathing machine (30).

3. The apparatus (10) according to claim 1 or 2, characterized in that The control unit (2) is set up for determining the first rotational speed level (n1) and the second rotational speed level (n2) on the basis of a pre-given pressure value and / or a pre-given volume flow value.

4. The apparatus (10) according to any one of the preceding claims, characterized in that The control unit (2) is set up for determining the triggering point in time (to) on the basis of ventilation parameters of the breathing machine (30) during operation of the breathing machine (30) in a first operating mode.

5. The apparatus (10) according to any one of the preceding claims, characterized in that The control unit (2) is set up for determining the triggering point in time (to) on the basis of a point in time of a previous delivery phase of the breathing machine (30) during operation of the breathing machine (30) in a second operating mode.

6. The apparatus (10) according to any one of the preceding claims, characterized in that The control unit (2) is set up for incrementing a desired parameter by a constant value in a desired time range and determining the triggering point in time (to), wherein the triggering point in time (to) exists as soon as the desired parameter has reached a triggering threshold value.

7. The apparatus (10) according to claim 5, characterized in that The control unit (2) is set up for incrementing the desired parameter until the start of a delivery phase of the breathing machine (30) and adapting the triggering threshold value in the event of a deviation of the triggering threshold value from the desired parameter being determined.

8. The apparatus (10) according to claim 6, characterized in that 9. A breathing machine (30) having a device (10) according to any one of the preceding claims.

10. A method for generating a pre-pressure (P) at a regulating valve (3) of a breathing machine (30), the breathing machine comprising a control unit (2) and a blower (1), wherein the blower (1) takes in ambient air through an inlet (31), compresses it and delivers it to the regulating valve (3), and wherein the control unit (2) carries out the following steps: - receiving a pressure value and / or a volume flow value, ​ - determining a first rotational speed level (n1) and a second rotational speed level (n2) based on the pressure value and / or the volume flow value, wherein the first rotational speed level (n1) is smaller than the second rotational speed level (n2), - operating the blower (1) with a control signal according to the first rotational speed level (n1), - determining a triggering point in time (t0), - operating the blower (1) with a control signal according to the second rotational speed level (n2) at the triggering point in time (t0), and - operating the blower with a control signal time-delayed with respect to the triggering point in time (t0) and within the same breathing cycle of the breathing machine (30) such that a rotational speed (N) smaller than the second rotational speed level (n2) results.

11. The method of claim 10, wherein, The triggering point in time (t0) is located in time before the start of a delivery phase of the breathing machine (30).

12. The method according to claim 10 or 11, characterized in that, During the delivery phase of the breathing machine (30) or after the delivery phase of the breathing machine (30), the rotational speed (N) is decreased from the second rotational speed level (n2).

13. A computer program product comprising instructions which, when executed by a control unit (2), cause the control unit (2) to implement a method for generating a pre-pressure (P) at a regulating valve (3) of a breathing machine (30), the breathing machine (30) comprising a device (10) having a regulating valve (3), the control unit (2) and a blower (1), wherein the blower (1) sucks in ambient air through an inlet (31), compresses it and delivers it to the regulating valve (3), the method having the following steps: - receiving a pressure value and / or a volume flow value, - determining a first rotational speed level (n1) and a second rotational speed level (n2) based on the pressure value and / or the volume flow value, wherein the first rotational speed level (n1) is smaller than the second rotational speed level (n2), - operating the blower (1) with a control signal according to the first rotational speed level (n1), - determining a triggering point in time (t0), - operating the blower (1) with a control signal according to the second rotational speed level (n2) at the triggering point in time (t0), and - operating the blower with a control signal time-delayed with respect to the triggering point in time (t0) - and within the same breathing cycle of the breathing machine (30) such that a rotational speed (N) smaller than the second rotational speed level (n2) results.

14. The computer program product of claim 13, wherein, The triggering point in time (t0) is located in time before the start of a delivery phase of the breathing machine (30).

15. The computer program product according to claim 13 or 14, characterized in that, During the delivery phase of the breathing machine (30) or after the delivery phase of the breathing machine (30), the rotational speed (N) is decreased from the second rotational speed level (n2).

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