Method for operating an actuating element in a medical device and device in this regard

Abstract

The invention relates to a method for operating an execution element (22) in a medical device (20), wherein the execution element (22) is connected to a hose system. The medical device (20) has a control device (28) with a pressure regulator (35) for regulating the gas pressure and a computing system (30), wherein the method comprises the following steps: - providing a nasal catheter on the hose system, - setting a nasal gas end pressure on the pressure regulator (35), - regulating the nasal gas pressure on the execution element (22) by means of the pressure regulator (35), in particular towards the nasal gas end pressure, - delivering the regulated gas from the execution element (22) to the hose system. The invention also relates to a device for operating an execution element (22).

Description

TECHNICAL FIELD

[0001] The invention relates to a method for operating an execution element in a medical device according to claim 1 and to a device according to the preamble of claim 9 for this aspect. BACKGROUND

[0002] Nasal air flow therapy or high flow oxygen therapy (HFOT) is a type of respiratory therapy, mainly used in hospitals, during which oxygen is provided to a patient together with compressed air and the breathing air is humidified. The flow rate is higher than in conventional oxygen therapy.

[0003] High flow oxygen therapy is commonly used in a clinical setting for patients with acute respiratory failure, such as hypoxemia, respiratory failure. These patients are usually admitted to an intensive care unit or a monitoring room and require respiratory support to stabilize their condition and monitor blood gases.

[0004] WO 2015 / 155342 A1 shows a high flow oxygen therapy system with a gas source, a humidifier, an atomizer, a nasal external interface and a gas aerosol supply line and a gas supply line. The gas aerosol supply line and the gas supply line are controlled with valves, wherein flow regulating devices are provided, which regulate the gas aerosol flow and the gas flow in the system.

[0005] Various medical devices on the market can use high flow oxygen therapy, such as the HFT500 device of the company MEK-ICS CO., LTD. (www.mek-ics.com). This medical device comprises an execution element and a hose system interface for connecting a hose system to the execution element. The hose system usually comprises a nasal catheter.

[0006] A disadvantage of the known solution is that the medical devices are set up and adjusted for the gas flow. The breathing work is increased by the constant gas flow, which in turn leads to fatigue or stress of the patient.

[0007] US 2012 / 009061 0 A1 discloses a CPAP device and a method for determining the airflow characteristics of a mask system for treating sleep disordered breathing (SDB), by which different mask systems can be characterized. An air supply hose and a patient connection device or a patient interface with a diffuser are shown as mask systems. The CPAP device has a flow generator which is connected to the mask system and has a controllable blower, a flow sensor and a pressure sensor and a processor. The processor is correspondingly configured to determine the airflow characteristics at the diffuser outlet. Similar types of devices are disclosed in WO 201 1 / 054038 A1, US 2016 / 287824 A1, WO 2017 / 109634 A1 and US 2018 / 036499 A1.

[0008] The disadvantage of the above-mentioned solutions is that none of the devices mentioned here has a pressure regulator which is suitable for adjusting the nasal air pressure of different mask systems, which leads to excessive gas consumption in the device. SUMMARY

[0009] The object of the present invention is to at least partially overcome one or more of the disadvantages of the state of the art. In particular, to create a method for operating an execution element in a medical device and a device in this regard, which reduces the gas consumption in the medical device.

[0010] The task is solved with the method and device defined in the independent claims. Advantageous further developments are set out in the dependent claims and the drawings.

[0011] The invention relates to a method for operating an execution element in a medical device, wherein the execution element is connected to a hose system and the medical device has a control device with a pressure regulator for adjusting the air pressure and a computing system, wherein the method comprises the following steps:

[0012] Setting a nasal catheter on the hose system (step a);

[0013] Setting a nasal gas end pressure on the pressure regulator (step b);

[0014] Adjusting the nasal air pressure on the execution element by means of the pressure regulator, in particular towards the nasal gas end pressure (step c);

[0015] Conveying the adjusted gas from the execution element to the hose system (step d).

[0016] The method is particularly performed before nasal air flow therapy or high flow oxygen therapy is carried out on a patient, wherein the patient has to reduce his breathing work due to a pressure adjustment during the subsequent nasal air flow therapy. The pressure adjustment device is adjusted to a specified constant gas pressure. In this application case the required gas or breathing gas peak flow can be covered and a lower gas consumption can be achieved in the medical device, wherein the applied oxygen concentration remains constant. Nasal air pressure means the gas pressure behind the hose system. The adjusted gas has a gas pressure and a gas flow specified by the actuating element. The hose system usually comprises a hose and a nasal catheter.

[0017] The medical device is advantageously a breathing machine, wherein the lung pressure of the patient can be better controlled or set by means of the pressure adjustment on the actuating element. By means of the method according to the application, based on the adaptive gas flow, the patient experiences a higher comfort.

[0018] The pressure regulator is preferably implemented based on at least one nasal pressure measurement or based on at least one pressure approximation. In the case of implementation of the pressure regulator based on at least one nasal pressure measurement, the method described here can be performed without an adjustment step. The medical device then automatically adapts to changes in the hose system. In the case of implementation of the pressure regulator based on at least one pressure approximation, the nasal pressure measurement can be dispensed with, so that the hose system can be produced more economically and the medical device can be operated with different hose systems or hose system accessories, thus making it more versatile.

[0019] It is very preferred to vary the nasal air flow in the hose system. In this way at least one pressure approximation can be determined for different nasal air flows, wherein the nasal catheter is usually not connected to the patient. For example, the nasal air flow varies linearly, so that at least one pressure approximation can be easily determined. Nasal air flow means the gas flow in the hose system.

[0020] The nasal air flow is preferably varied between 0 liters per minute and 100 liters per minute. In this way the nasal air flow can be changed from a high flow value to a low flow value or vice versa from a low flow value to a high flow value. In this way a large number of approximation pressure values can be determined, which can serve as a basis for a very precise pressure adjustment on the actuating element.

[0021] The variation of the nasal air flow takes place in particular within a predetermined time interval, for example within 10 seconds. In this way at least one pressure approximation value can be determined in a reproducible manner.

[0022] The variation of the nasal air flow in the hose system preferably takes place before the nasal gas end pressure is set on the pressure regulator (step b)). In this way the medical device can be adjusted to the configuration of the device hose system before it is applied to the patient, so that excessively high gas pressures are avoided and a higher patient safety is subsequently ensured.

[0023] In a preferred manner, the at least one pressure approximation is calculated on the basis of at least one internal pressure measurement and on the basis of at least one pressure difference approximation in the hose system. The at least one internal pressure measurement can be determined in this case by means of a pressure sensor in the medical device, which is arranged in the region of the hose system interface. An external pressure sensor on the hose system is thus not required.

[0024] The at least one pressure difference approximation in the hose system is preferably calculated on the basis of the internal gas flow. The internal gas flow is measured by means of a flow sensor arranged in the medical device, or is determined indirectly by means of a suitable flow measurement method on the basis of the pressure difference. In this way, the at least one pressure approximation can be determined precisely by means of a simple measuring device with exactly one pressure sensor and exactly one flow measurement sensor, by means of which the gas consumption in the medical device can be determined accurately, and in addition excessive gas consumption is prevented.

[0025] The at least one pressure difference approximation is determined in particular by means of a mathematical function, by means of which the at least one pressure approximation can be determined reliably in the adjustment step. The mathematical function is for example a polynomial function, or for example a quadratic function which is solved for example by means of the least squares method. In this way, the at least one pressure approximation is determined in a particularly simple manner.

[0026] The at least one pressure difference approximation is preferably retrieved from a table in the computing system. The at least one pressure difference approximation can be provided or preconfigured by the manufacturer of the medical device in this case, or can be saved in the table in the computing system during the adjustment step. In this case, a pressure difference approximation is assigned to each internal gas flow value, so that the pressure difference approximation can be inferred from the measured gas flow value.

[0027] The at least one pressure difference approximation is determined in particular by means of at least one transnasal pressure measurement. In this way, the at least one pressure difference approximation can also be determined during use of the medical device, by means of which patient safety is improved. In this case, the at least one internal pressure measurement is supplemented by at least one transnasal pressure measurement, and the at least one pressure approximation is determined therefrom. In this case, the transnasal pressure measurement is used to detect changes in the hose system automatically, for example after a change of nasal cannula on the hose system.

[0028] In a preferred manner, a minimum gas flow through the hose system is determined. By applying the minimum gas flow, it can be ensured that the carbon dioxide separation in the breathing gas is ensured. In this case, the minimum gas flow can be entered easily by the user in the medical device in accordance with the height or ideal body weight and / or the patient gender, or determined by means of a given theory, for example on the basis of OTIS.

[0029] In a preferred manner, the at least one pressure approximation is calculated in the computing system using

[0030]

[0031] The minimum gas flow is calculated, wherein Vd is the dead space, k is a factor between 0.05 and 2, T e The minimum airflow can thus be adjusted without the need for assistance from the user of the medical device, thus reducing the burden on the user.

[0032] In particular, the dead space V is calculated using the patient's ideal weight and Radford constant. d , where the Radford constant is typically 2.2 ml / kg. This allows the dead space V to be easily determined for most applications. d .

[0033] The coefficient k=0.33 is preferably used for calculating the minimum airflow, which allows easy calculation of the minimum airflow and ensures a high degree of patient safety.

[0034] Especially T e The exhalation time is calculated by the computer system. This allows the minimum airflow to be coordinated with the patient's current breathing activity.

[0035] Alternatively, the minimum air flow can be determined using a flow approximation, which is based on an internal air flow and a leakage flow in the hose system. The leakage flow can usually be calculated using the nasal air pressure.

[0036] For this purpose, the dead space V is estimated based on an estimate derived from the flow approximation. d , for example based on minute ventilation M v , respiratory frequency f, and expiratory time constant RC-, so as to automatically determine the dead space V in the calculation system of the medical device d Dead Space V d For example, through

[0037]

[0038] OK. Then as mentioned above, the dead space V can be used d The minimum air flow is calculated. The user does not have to make any settings on the medical device for this. The algorithm ensures that CO2 separation is always within the optimal range.

[0039] The minimum air flow is preferably set to a value between 0 and 100 liters per minute. In this way, the minimum air flow can be limited to a value suitable for a specific patient.

[0040] The minimum flow rate calculated is preferably limited, with the effective internal maximum flow rate serving as a point of departure. The effective internal maximum flow rate of the gas in the hose system can be determined, for example, in a medical device by measuring the flow rate with an internal flow rate measuring sensor in the medical device over a specified period of time. This period of time is typically in the range from 10 seconds to 60 seconds, in particular in the range from 25 seconds to 45 seconds, in particular 36 seconds. By further limiting the internal flow rate, a patient safety is ensured, which is dependent on the carbon dioxide separation.

[0041] The minimum flow rate calculated is preferably limited, with the effective internal maximum flow rate serving as a point of departure. The effective internal maximum flow rate of the gas in the hose system can be determined, for example, in a medical device by measuring the flow rate with an internal flow rate measuring sensor in the medical device over a specified period of time. This period of time is typically in the range from 10 seconds to 60 seconds, in particular in the range from 25 seconds to 45 seconds, in particular 36 seconds. By further limiting the internal flow rate, a patient safety is ensured, which is dependent on the carbon dioxide separation.

[0042] The maximum average flow rate through the hose system is preferably set. The flow rate is allowed to exceed this maximum value occasionally, but on average it must remain below the maximum average flow rate, which is understood as a limit. This limit ensures sufficient humidification of the gas supplied in the hose system.

[0043] The average maximum flow rate is preferably set to a value between 10 liters per minute and 200 liters per minute. This ensures that sufficiently humidified gas can be supplied to the patient.

[0044] The average maximum flow rate is preferably set to a value between 10 liters per minute and 200 liters per minute. This ensures that sufficiently humidified gas can be supplied to the patient.

[0045] The average maximum flow rate is adjusted, in particular, on the basis of a gas humidity measurement. The average maximum flow rate is adjusted by a flow rate regulator in the medical device on the basis of the determined gas humidity measurement. In this way, gas with the desired humidification can be supplied in the hose system. For example, the medical device is connected to a humidifier or itself contains a humidifier.

[0046] As an alternative, the average maximum flow rate is determined on the basis of the oxygen concentration in the gas. The oxygen concentration is typically measured or determined. In this way, a high average oxygen flow is prevented.

[0047] The nasal flow rate is adjusted in a preferred manner so that it is always in the range between the minimum flow rate and the average maximum flow rate, thus ensuring for the patient carbon dioxide separation, gas humidification, and a too high oxygen consumption.

[0048] The nasal flow rate is preferably adjusted as an internal cascade of the nasal air pressure, thus using a cascade-like adjustment mechanism which ensures that the nasal flow rate is between the required minimum flow rate and the required average maximum flow rate.

[0049] The automatic setting of the nasal gas end pressure (step b)) is preferred, so that the user of the medical device does not have to manually set this parameter and thus a higher patient safety is achieved. The setting of the nasal gas end pressure is the responsibility of a regulation algorithm in the medical device computing system.

[0050] The minimum internal gas flow measured in the medical device and the minimum gas flow are preferably zero-adjusted in the regulation algorithm and the nasal gas pressure is regulated towards the nasal gas end pressure. In other words, if the measured minimum internal gas flow is lower than the minimum gas flow to be achieved, which is set by the medical device or by the operator of the medical device, the regulation algorithm increases the nasal gas pressure. If the measured minimum internal gas flow is higher than the minimum gas flow to be achieved, which is set by the medical device or by the operator of the medical device, the regulation algorithm relatively reduces the nasal gas pressure, wherein the internal cascade flow regulator does not limit the minimum gas flow. Thus, the medical device can always be regulated to the optimum nasal gas end pressure.

[0051] The minimum internal gas flow in the medical device can be determined by measuring the gas flow using an internal flow measuring sensor in the medical device over a specified time period. This time period is usually in the range of 0.5 seconds to 50 seconds, in particular in the range of 2 seconds to 30 seconds.

[0052] The nasal gas end pressure is preferably regulated on the basis of blood gas values. The blood gas values are measured beforehand, for example. The nasal gas end pressure is increased or decreased depending on the level of the measured blood gas values. Thus, the nasal gas end pressure can be regulated for each patient.

[0053] The blood gas values are in particular carbon dioxide values, for example transcutaneous carbon dioxide values or arterial carbon dioxide partial pressure values, or oxygen saturation values, for example blood oxygen saturation values. Thus, the nasal gas end pressure can be regulated using commonly used blood gas values.

[0054] The nasal gas end pressure is preferably limited to a value between 0.1 mbar and 20 mbar, so that a low gas consumption is maintained.

[0055] The control device preferably generates suitable control commands for the execution element on the basis of the predetermined nasal gas flow, so that the execution element delivers the adjusted gas accordingly to the hose system. Thus, the gas consumption in the medical device is optimized. As a non-exhaustive list of examples, the control commands are a voltage value, a rotational speed value or a current value, or are specified on the basis thereof.

[0056] Alternatively or additionally, the control device generates suitable control commands for the execution element on the basis of the predetermined nasal gas pressure, so that the execution element delivers the adjusted gas accordingly to the hose system. Thus, not only is the gas consumption in the medical device optimized, but also a higher patient comfort is ensured.

[0057] A further aspect of the application relates to a device for carrying out nasal air flow therapy, comprising an execution element, a hose system interface for connecting a hose system to the execution element, and at least one measuring transducer which provides a measuring signal from at least one pressure sensor. In addition, there is a control device with a pressure regulator for regulating the nasal air pressure.

[0058] The pressure regulator in the device, for example a medical device, facilitates the reduction of the patient's breathing work when receiving nasal air flow therapy. The pressure regulator is correspondingly configured for this purpose, so that a constant air pressure is adjusted. In this application case, the required peak flow of the air or breathing gas can be covered and a lower gas consumption can be achieved in the medical device, wherein the applied oxygen concentration can remain constant.

[0059] The execution element described here generally comprises at least one blower for regulating the air, so that the medical device can be used in a private household.

[0060] Alternatively or additionally, the execution element described here comprises at least one air source with a valve for regulating the air. In this way, the existing infrastructure in a hospital can be used. Alternatively, the existing infrastructure in a hospital can be used to assist in the medical device when using a blower and an air source with a valve. In addition, different oxygen concentrations can be set directly on the medical device by means of this.

[0061] Preferably, a computing system is included, to which the execution element is connected and which is configured to calculate at least one pressure approximation on the basis of at least one internal pressure measurement and on the basis of at least one differential pressure approximation in the hose system. For this purpose, the at least one internal pressure measurement can be determined by a pressure sensor in the medical device, which is arranged in the region of the hose system interface. No additional pressure sensor is therefore required on the hose system. A digital-analog measuring transducer is generally present in the device, preferably between the computing system and the execution element, wherein the digital-analog measuring transducer converts the values calculated in the computing system into control commands for the execution element.

[0062] The computing system in particular has a calculation algorithm which has been configured to carry out the method described here. The method described here can therefore be carried out fully automatically.

[0063] The computing system preferably has a storage unit. The values suitable for pressure regulation, for example the at least one internal pressure measurement or the at least one differential pressure approximation, can therefore be saved in the storage unit so that they can be easily retrieved if necessary.

[0064] The pressure regulator is preferably configured to adjust the nasal air pressure on the basis of at least one pressure approximation. In the case of a pressure regulator which is implemented on the basis of at least one pressure approximation, the nasal pressure measurement can be dispensed with, thus enabling the nasal catheter to be produced more economically and the medical device to be operated with different hose systems or hose system accessories, thus making it more versatile.

[0065] Preferably, a pressure measurement device is included for detecting at least one nasal pressure measurement, wherein the pressure regulator adjusts the nasal air pressure downstream of the hose system on the basis of at least one nasal pressure measurement. The nasal pressure measurement is thus used to automatically detect changes in the hose system, for example after a nasal catheter has been replaced on the hose system, thus enabling the adjustment step to be dispensed with.

[0066] Preferably, a flow measurement sensor for measuring the internal gas flow is included in the medical device. The flow measurement sensor preferably measures the internal gas flow delivered by the actuating element, thus enabling the gas consumption to be optimized and ensuring the carbon dioxide separation.

[0067] Preferably, a humidifier is included, wherein the humidifier is preferably arranged on the hose system. High-flow humidified oxygen therapy has been successfully used for patients with COPD, bronchiectasis, advanced cancer and patients who cannot be intubated, who require ideally humidified gas.

[0068] The humidifier is in particular designed for adjusting the gas temperature. This enables the humidification in the gas to be further optimized.

[0069] Preferably, a temperature control system is included for temperature adjustment of the conditioned gas, thus preventing the humidified air from condensing and thus increasing the partial pressure of the water vapor reaching the patient.

[0070] Preferably, the temperature control system is arranged in the hose system for temperature adjustment of the conditioned gas, thus adapting the temperature control to the hose system and providing ideally temperature-adjusted gas.

[0071] As an alternative, a humidifier and a temperature control system are included, thus providing ideally conditioned gas. The humidifier and the temperature control system are preferably combined in one system.

[0072] As an alternative, the humidifier and / or the temperature control system are arranged in the device. The size of the humidifier built into the device is determined in accordance with the device parameters, thus enabling the device to be produced cost-effectively and the user to require no additional equipment.

[0073] In a preferred manner, a flow regulator is included for regulating the nasal air flow. This enables the flow to be regulated in addition to the pressure, thus ensuring the gas consumption, the carbon dioxide separation and the humidification.

[0074] In particular, a cascade control is provided, in which a pressure regulator for regulating the nasal gas pressure forms the outer cascade and a flow regulator for regulating the nasal gas flow forms the inner cascade. In this way, it is not possible to fall below the minimum gas flow through the hose system described herein or to exceed the maximum average gas flow through the hose system described herein, thereby additionally ensuring the separation of the carbon dioxide component in the gas, the sufficient humidification of the gas and the ideal gas consumption.

[0075] Preferably, an oxygen metering device is provided, by means of which the oxygen concentration can be set on the device.

[0076] Preferably, an input device is provided, so that the user of the device can manually set or enter settings, such as the nasal gas end pressure and / or the oxygen concentration.

[0077] The input device has in particular a display unit. In this way, the settings set by the user are usually displayed, by means of which the user can easily visually check the settings on the device.

[0078] The input device is preferably designed as a touchscreen, by means of which the device can be easily operated and has an extremely compact input device.

[0079] The input device preferably has at least one switching device for selecting between automatic pressure regulation or constant pressure regulation. In the case of automatic pressure regulation, the user cannot set the nasal gas end pressure himself, but the medical device automatically calculates the optimum nasal gas end pressure. The switching device is integrated in the touchscreen. In this way, the operator of the medical device can easily enter. As an alternative, the switching device is designed as a mechanical switch. In this way, the operator can see the position of the mechanical switch, for example, from a distance.

[0080] In a preferred manner, a measuring device for measuring the blood gas is provided. Based on the blood gas measurement values extracted therefrom, the nasal gas end pressure can be automatically adjusted.

[0081] Preferably, a carbon dioxide measuring device is provided. In this way, the carbon dioxide measurement values are taken into account in the pressure regulation, so that on the one hand a sufficiently high gas pressure and a sufficiently high gas flow are provided.

[0082] As an alternative or in addition, an oxygen measuring device is provided. The oxygen measuring device is connected to the device or integrated in the device. In this way, the oxygen measurement values are taken into account, so that a sufficient amount of oxygen is provided.

[0083] The method described herein is preferably implemented as a computer-implemented method for operating the execution element. In this way, the control device and the computing system in the medical device are correspondingly configured, so that the method described herein can be automatically executed. In this way, the production costs are reduced.

[0084] The computer-implemented method disclosed herein is preferably saved on a storage medium. The storage medium can be integrated in the device on the one hand, or it can be a mobile storage medium. The mobile storage medium can be connected to different devices, so that the method disclosed herein can be used in different locations.

[0085] In particular, control commands for the actuating element are saved on the storage medium. The storage medium is inserted into the medical device, so that the commands can be immediately retrieved and the actuating element can be driven by the control commands.

[0086] Further advantages, features and details of the application are described in the following description, in which embodiments of the application are explained with reference to the drawings.

[0087] The list of reference signs and the technical content and the figures in the patent claims are part of the patent disclosure. The drawings are presented in a context-related and comprehensive manner. Identical parts are indicated by identical reference signs, and reference signs with different indices indicate functionally identical or similar parts. BRIEF DESCRIPTION OF DRAWINGS

[0088] BRIEF DESCRIPTION OF DRAWINGS:

[0089] Figure 1 System for performing nasal air flow therapy,

[0090] Figure 2 First embodiment of a device for performing nasal air flow therapy according to the application,

[0091] Figure 3 Another embodiment of a device for performing nasal air flow therapy according to the application,

[0092] Figure 4 Flow chart of a first embodiment of a method without pressure measurement device according to the application, and

[0093] Figure 5 Flow chart of another embodiment of a method with pressure measurement device according to the application. DETAILED DESCRIPTION

[0094] Figure 1 A system 15 for performing nasal air flow therapy on a patient is shown. The system 15 comprises a hose system 17 and a medical device 20 with an actuating element 22. The hose system 17 comprises a hose 18 and a nasal catheter 16 and is connected to the actuating element 22 of the medical device 20. A humidifier 19 is arranged along the hose 18. The actuating element 22 supplies the hose system 17 or the nasal catheter 16 with a conditioned gas, which is released into the environment or supplied to the patient via the hose system 17 or via the nasal catheter 16. Depending on the gas composition, this can be a breathing gas, for example, which is supplied to the patient to support breathing.

[0095] Figure 2 Shown Figure 1 The medical device 20 in the figure is according to a first embodiment of the present invention and comprises a hose system connection 23 for connecting the hose system 17. The actuator 22 in the medical device 20 has a digital-analog measuring transducer 24 and is connected to the hose system connection 23. As a non-exhaustive list, the actuator 22 comprises a ventilator and / or an oxygen connection and a valve, and in particular a humidifier (not shown).

[0096] The medical device 20 has a control device 28, which includes a computing system 30, a storage unit 32, and a cascade regulating mechanism 36. In the control device 28, the computing system 30, the storage unit 32, and the cascade regulating mechanism 36 are connected to each other to exchange data. The storage unit 32 has a table 33 for storing air pressure data and airflow data. The control device 28 has a table for regulating the nasal air pressure P nasal The pressure regulator 35 is connected to the flow regulator 40 to exchange data. The pressure regulator 35 is configured accordingly so that the actuator 22 adjusts the gas to a constant nasal pressure P nasal The control device 28 has a function for adjusting the nasal airflow P nasal The flow regulator 40 is electrically connected to the digital-analog measuring transmitter 24 of the actuator 22. To this end, the pressure regulator 35 and the flow regulator 40 are connected to each other via a cascade control mechanism 36, wherein the pressure regulator 35 forms an external cascade device and the flow regulator 40 forms an internal cascade device.

[0097] The medical device 20 has an internal pressure sensor 38 to measure the internal pressure P set or generated by the actuator 22. int These are supplied to the control device 28 as pressure measurement signals by means of an analog-to-digital measuring transducer 39 .

[0098] The medical device 20 has a flow measurement sensor 41 for measuring the internal air flow F set or generated by the actuator 22. int These are provided to the control device 28 as flow measurement signals by means of an analog-to-digital measuring transducer 42 .

[0099] Medical device 20 includes an input / output device 45 comprising a display unit 46 and a touch screen 47 for inputting and displaying air pressure values ​​and / or air flow values ​​or air pressure data and / or air flow data. Input / output device 45 also includes a switching device 48 for selecting between automatic pressure regulation and constant pressure regulation. Input / output device 45 is connected to control device 28 to exchange data.

[0100] The medical device 20 has a connecting plate 49 for connecting a measuring device or metering device. The connecting plate 49 is connected to the control device 28. As a non-exhaustive list, for example, a measuring device for blood gas measurement (e.g., for carbon dioxide measurement and / or oxygen measurement), an oxygen metering device with an oxygen connection, and a valve (not shown) can be connected to this.

[0101] Figure 3 The medical device 120 shown in FIG. 1 is substantially consistent with the Figure 2 The medical device 20 is different from the medical device 120 in that there is a device for detecting the nasal pressure measurement value P mes The medical device 120 is provided with a pressure measuring device 160 and is preferably a ventilator. For this purpose, the medical device 120 has a control device 128 which has Figure 2 Furthermore, the medical device 120 has an input and output device 145 which has Figure 2 The components and their technical functions described in.

[0102] The pressure measuring device 160 is connected to the connecting plate 149. The nasal pressure measurement value P measured by the pressure measuring device 160 is converted to mes The measured nasal pressure value P is transmitted to the control device 128. mes The pressure is converted into a control command in the pressure regulator 135 of the control device 128 to adjust the actuator 122. The control device 128 has a pressure regulator for adjusting the nasal airflow P nasal The flow regulator 140 is electrically connected to the digital-to-analog measuring transducer 124 of the actuator 122. The pressure regulator 135 and the flow regulator 140 are connected via a cascade control mechanism 136, with the pressure regulator 135 forming the outer cascade and the flow regulator 140 forming the inner cascade. The control commands are transmitted to the actuator 122 via the digital-to-analog measuring transducer 124.

[0103] Figure 4 A first embodiment of the method according to the invention is shown for Figure 1 and 2 The actuator 22 is operated in the medical device 20. The hose system interface 23 is previously connected to the hose 18 of the hose system 17, and the nasal cannula 16 is arranged or placed on the hose system 17 (step 70; step a)). It is then ensured that the nasal cannula 16 is not placed on the patient (step 71). The following steps are used to adjust the medical device 20 together with the hose system 17, wherein the internal gas flow F intfrom 0 liters per minute linearly to 100 liters per minute (step 72) over a period of 10 seconds. During this period, the internal air pressure value P int and the internal air flow value F int are measured using the internal pressure sensor 38 and the internal flow measuring sensor 41 and transmitted to the control device 28. The individual pressure difference approximations dP int are then calculated in the computing system 30 on the basis of the measured internal air pressure or the measured internal air pressure value P n and on the basis of the pressure approximations P sch where

[0104] P n = P int -dP sch ,

[0105] and on the basis of P n = 0, the approximation dP sch = P int applies.

[0106] The individual internal air pressure measurements P int thus correspond to the pressure difference approximations dP sch in the hose system 17. These are saved in the table 33 of the storage unit 32 together with the measured internal air flow values F int associated therewith (step 73), whereby the medical device 20 is adjusted by the connected hose system.

[0107] As an alternative, the respective pressure difference approximations dP sch can be calculated using mathematical functions in order to adjust, for example, using a polynomial function, such as

[0108]

[0109] for example. The constants R0, R1,... are then determined using the least squares method. As a non-exhaustive list, other functions for determining the pressure difference approximations dP int on the basis of the internal air flow F sch are linear or quadratic functions.

[0110] In a further step (step 74), the maximum average air flow F max through the hose system 17 is set to 100 liters per minute.

[0111] The ideal body weight (IBW) of the patient (or the height and gender of the patient) is then set on the input and output device 45, as well as the oxygen concentration FiO2 in the medical device 20, and the measured effective internal maximum air flow F int,max and the exhalation time T e are calculated in the computing system 30 (step 75).

[0112] In addition, the dead space V d is calculated by means of the ideal body weight (IBW) and the Radford constant d = 2.2 ml / kg * IBW) (step 76).

[0113] The individual pressure approximations P int are then determined in the computing system 30 by means of the measured internal gas pressure measurements P sch and the differential pressure approximations dP n , which are saved in the table 33. int The differential pressure approximations dP sch are determined by means of the measured internal gas flow F min (step 77).

[0114] The minimum gas flow F min through the hose system is then determined (step 78).

[0115] The final gas flow F min is then determined in the computing system 30 using

[0116]

[0117] is calculated, wherein V d is the dead space determined previously, k is equal to 0.33, and T e is the exhalation time calculated previously.

[0118] In a further step (step 79), it is inquired in the medical device 20 whether the nasal gas end pressure P nSet should be set automatically. This inquiry is made via the position of the switch means 48 on the medical device 20 or by a setting specified in the control means 28.

[0119] In the case of non-automatic setting of the nasal gas end pressure P nSet , the user manually set nasal gas end pressure P nSet is read by the input and output means 45 on the medical device 20 (step 80; step b)).

[0120] The final gas flow F nSet is then determined from the difference between the set nasal gas end pressure P nSet and the previously determined pressure approximation P n , whereby the above-mentioned difference is converted to zero (zero adjustment) according to

[0121] F nSet is thus calculated: P nSet - P n → 0,

[0122] This leads to the final pressure of nasal gas P nSet Adjust nasal air pressure P nasal (Step 81 ; Step c)) Thus, the pressure regulator 35 is first implemented as an external cascade of a cascade control mechanism.

[0123] In addition, the final gas flow rate F determined in step 81 is nSet According to the previously determined maximum average airflow F max Determine the upper limit and based on the previously determined minimum airflow F min A lower limit is determined (step 82).

[0124] As an alternative to the aforementioned steps (steps 80 to 82), in the automatic determination of the nasal gas terminal pressure P nSet The measured effective minimum internal airflow F int,min (Step 83), and inquire about the calculated minimum airflow F min Is it less than the determined and measured effective internal minimum airflow F int,min (Step 84).

[0125] If the calculated minimum airflow F min Less than the determined and measured effective minimum internal airflow F int,min , the control device 28 reduces the nasal gas final pressure P nSet , and set it (step 85; step b)).

[0126] If the calculated minimum airflow F min Greater than the determined and measured effective minimum internal airflow F int,min , the control device 28 increases the nasal gas final pressure P nSet , and set it (step 86; step b)).

[0127] In both cases, the nasal end pressure P nSet The limit is set to a value between 0 mbar and 10 mbar (step 87).

[0128] Then, in step 88 , the pressure regulator is implemented as an outer cascade of a cascade control mechanism.

[0129] According to the previously determined maximum average airflow F max Determine the final gas flow rate F nSet and determine the lower limit to be zero (step 89).

[0130] Then, by means of the flow regulator 40 and also by means of the actuator 22, the calculated final gas flow F nSet Adjust the measured internal airflow F int(step 90). In other words, a zero-point adjustment is carried out, according to which

[0131] F nSet F int → 0,

[0132] so as to move towards the calculated final gas flow F nSet The nasal gas flow F nasal is adjusted. This implements the flow regulator as an inner cascade of the cascade regulator.

[0133] The control device 28 then generates suitable control commands for the execution element 22 on the basis of step 90 and transmits them to the execution element 22, which accordingly delivers the adjusted gas to the hose system (step 91; step d)).

[0134] Steps 75 to 82 and steps 89 to 91 can also be carried out several times.

[0135] As an alternative, steps 75 to 79 and steps 83 to 91 can be carried out several times.

[0136] Figure 5 Another embodiment of the method according to the application is shown for operating the aforementioned execution element 122 in a medical device 20 according to Figure 1 and a medical device 120 according to Figure 3 which contains or is connected to a pressure measurement device 160 for detecting a pressure measurement value P mes .

[0137] In a first step (step 170), the maximum average gas flow F max through the hose system is set to 100 liters per minute.

[0138] The ideal body weight (IBW) of the patient (or the height and gender of the patient) is then set, as is the oxygen concentration (FiO2) in the medical device 120, and the measured effective internal maximum gas flow F int,max and the exhalation time T e are calculated (step 171).

[0139] In addition, the dead space V d is calculated with the aid of the ideal body weight (IBW) and the Radford constant, which is usually 2.2 ml / kg (V d = 2.2 ml / kg * IBW) (step 172).

[0140] The minimum gas flow F min through the hose system is then determined (step 173).

[0141] This minimum gas flow Fmin In a computing system

[0142]

[0143] is calculated, wherein V d is the dead space determined previously, k is equal to 0.33, T e is the exhalation time calculated previously.

[0144] The user manually set nasal gas end pressure P nSet is then read by the input and output means 145 on the medical device 120 (step 174; b)).

[0145] The nasal pressure measurement P mes is additionally measured by means of the pressure measuring means 160,

[0146] and transmitted by the analog-digital measuring transducer 150 to the pressure regulator 135 of the control means 128 (step 175).

[0147] The final gas flow F nSet is then determined from the difference between the first set nasal gas end pressure P mes and the previously measured nasal pressure measurement P nSet , so that the above difference is converted to zero (zero point adjustment) according to

[0148] F nSet is thus calculated: P nSet - P mes → 0,

[0149] by means of which the nasal pressure P nSet is adjusted towards the first set nasal gas end pressure P mes (step 176; step c)). The pressure regulator thus initially functions as an outer cascade of the cascade-like regulating mechanism.

[0150] The final gas flow F nSet determined in step 176 is additionally limited by an upper limit determined from the previously determined maximum average gas flow F max and by a lower limit determined from the previously determined minimum gas flow F min (step 177).

[0151] The measured internal gas flow F nSet is then adjusted by means of the actuating element 122 towards the calculated final gas flow F int (step 178). In other words, a zero point adjustment is carried out according to

[0152] F nSet - F int → 0,

[0153] The final gas flow F is thus calculated nSet Adjusting the nasal gas flow F nasal The flow regulator is thus implemented as an inner cascade of the cascade regulator.

[0154] The control device 128 then generates appropriate control commands for the execution element 122 on the basis of step 178 and transmits them to the execution element 122, as a result of which the execution element 122 delivers the adjusted gas to the hose system accordingly (step 179; step d)).

[0155] Steps 170 to 179 can be performed several times.

[0156] List of reference signs

[0157] 15 system

[0158] 16 nasal catheter

[0159] 17 hose system

[0160] 18 hose

[0161] 19 humidifier

[0162] 20 medical device

[0163] 22 execution element

[0164] 23 hose system interface

[0165] 24 analog-digital measuring transducer of 22

[0166] 28 control device

[0167] 30 calculation system

[0168] 32 storage unit

[0169] 33 table

[0170] 35 pressure regulator

[0171] 36 cascade regulator

[0172] 38 inner pressure measuring sensor

[0173] 39 analog-digital measuring transducer

[0174] 40 flow regulator

[0175] 41 inner flow measuring sensor

[0176] 42 analog-digital measuring transducer of 41

[0177] 45 input and output device

[0178] 46 display unit

[0179] 47 touch screen

[0180] 48 conversion device

[0181] 49 connecting plate

[0182] 120 medical device

[0183] 122 actuating element

[0184] 124 analog-digital measuring transducer of 122

[0185] 128 control device

[0186] 135 pressure regulator

[0187] 136 cascade regulator

[0188] 145 input and output device

[0189] 140 flow regulator

[0190] 149 connecting plate

[0191] 150 analog-digital measuring transducer

[0192] 160 pressure measuring device

[0193] 70-91 method steps

[0194] 170-179 method steps

[0195] P nSet first nasal gas end pressure

[0196] P nasal nasal gas pressure

[0197] P mes pressure measurement value

[0198] P n pressure approximation value

[0199] dP Sch first differential pressure approximation value

[0200] P int first internal pressure measurement value

[0201] F min minimum gas flow

[0202] F nasal nasal gas flow

[0203] Fmax Maximum average airflow

[0204] F int,max Effective internal maximum airflow

[0205] F int Internal airflow

[0206] F int,min Minimum internal airflow

[0207] F nSet Nasal final gas flow

Claims

1. A method for operating an actuator (22; 122) in a medical device (20; 120), wherein the medical device comprises an actuator (22; 122) and a control device (28; 128) as well as a computing system (30), wherein the actuator (22; 122) delivers regulated gas to a connected hose system (17), and wherein the control device (28; 128) has a cascaded regulating mechanism (36; 136) for regulating nasal air pressure (P nasal ) pressure regulator (35; 135) forms an external cascade and is also used to regulate nasal airflow (F nasa 1) forms an internal cascade, wherein the method comprises the following steps: a) providing a nasal cannula (16) for use with the hose system (17); b) determining the minimum airflow (F) through the hose system (17) and the nasal cannula (16) min ), wherein the minimum air flow (F min ), based on the internal air flow (F int ) and determining said flow approximation based on a leakage flow in said hose system (17); c) Set the nasal gas end pressure (P) on the pressure regulator (35; 135) nSet ); d) by said control device (28; 128) (1) regulating the actuator (22; 122) by means of the pressure regulator (35; 135) to move towards the nasal gas final pressure (P nSet ) regulates the nasal air pressure (P nasal ), where the pressure approximation (P n ) performs pressure control and based on at least one internal pressure measurement value (P int ) and based on at least one approximate pressure difference (dP) in the hose system (17) Sch )Calculate the approximate pressure value (P n ), and determine the approximate pressure difference (dP) without the nasal cannula being connected to the patient Sch );as well as According to the nasal gas final pressure (P nSet ) and the pressure approximation (P n The final gas flow rate (F nSet ), thereby converting the difference to 0, the final gas flow rate (F nSet ) is the minimum airflow (F min ), (2) by means of the flow regulator (40; 140) toward the final gas flow (F nSet ) adjusts the measured internal airflow (F int ), towards the final gas flow (F nSet ) regulates the nasal airflow (F nasa ); e) delivering the regulated gas from the actuator (22; 122) to the hose system (17).

2. The method according to claim 1, characterized in that The average maximum air flow (F max ), where the average maximum airflow (F max ) is set to a value between 10 liters per minute and 200 liters per minute.

3. The method according to claim 2, characterized in that The average maximum airflow (F max ) is set to 100 liters per minute.

4. The method according to any one of claims 1 to 3, characterized in that Regulates nasal airflow (F nasal ) as nasal pressure (P nasal )'s internal cascade.

5. The method according to any one of claims 1 to 3, characterized in that Automatically set the nasal gas end pressure (P nSet ), wherein the value is selected from the group consisting of carbon dioxide value, oxygen saturation value, and minimum flow (F min ) is adjusted based on the measured blood gas values ​​of the group.

6. The method according to claim 1, characterized in that The method also includes determining the pressure difference approximate value (dP Sch ): Changing the nasal airflow (F) through the hose system and the nasal cannula within a predetermined time window nasal ); During this time window: (i) measuring the internal air pressure (P) in the medical device (20; 120) generated by the actuator (22) int );as well as (ii) measuring the internal airflow (F) in the medical device (20; 120) generated by the actuator (22) int ); For each nasal airflow (F nasal ) and the measured internal airflow (F int ), calculate the approximate pressure difference (dP Sch );as well as Stores approximate differential pressure (dP Sch ) and the associated internal airflow (F int ) for the applied hose system (17) and nasal catheter (16).

7. The method according to claim 6, wherein the nasal airflow (F nasal ).

8. A device for performing nasal airflow therapy, comprising an actuator (22; 122), a hose system (17), a hose system interface (23) and at least one measuring transmitter (39), wherein: The hose system (17) comprises a tube (18) and a nasal cannula (16), wherein the hose system interface connects the hose system (17) to an actuator (22; 122), and wherein the at least one measuring transmitter is arranged to provide a measuring signal from at least one pressure sensor (38), characterized in that The device also comprises a hose system (17) with a cascade regulating mechanism (36; 136) and a pressure regulator (35; 135) for regulating nasal air pressure (P nasal ) control device (28; 128), wherein the nasal air pressure (P nasal ) of the pressure regulator (35; 135) forms an external cascade and is used to regulate the nasal airflow (F nasa l) of the flow regulator (40; 140) forming an internal cascade, the pressure regulator being configured to be based on at least one pressure approximation (P n ) towards the nasal end pressure (P nSet )Regulate nasal air pressure (P nasal ), and based on at least one internal pressure measurement (P int ) and based on at least one pressure difference approximation (dP Sch )Calculate the approximate pressure value (P n ), and determine the approximate pressure difference (dP) without the nasal cannula being connected to the patient Sch ), Wherein, the control device (28; 128) is configured to: Determine the minimum airflow (F) through the hose system (17) and the nasal cannula (16) min ), wherein the minimum air flow (F min ), based on the internal air flow (F int ) and determining said flow approximation based on a leakage flow in said hose system (17); By means of the pressure regulator (35; 135) according to the nasal gas final pressure (P nSet ) and the pressure approximation (P n The final gas flow rate (F nSet ), thereby converting the difference to 0, the final gas flow rate (F nSet ) is the minimum airflow (F min );as well as By means of the flow regulator (40; 140) towards the final gas flow (F nSet ) adjusts the measured internal airflow (F int ), towards the final gas flow (F nSet ) regulates the nasal airflow (F nasa ).

9. The device according to claim 8, characterized in that The invention comprises a computing system (30), wherein the actuator (22; 122) is connected to the computing system (30), and the computing system (30) has a storage unit (32), and the computing system (30) is configured to calculate the pressure based on the at least one internal pressure measurement value (P int ) and based on the at least one approximate pressure difference (dP) in the hose system (17) Sch ) calculates at least one pressure approximation (P n ).

10. The device according to claim 8 or 9, characterized in that A humidifier (19) is included, wherein the humidifier (19) is arranged on the hose system (17) and / or a temperature control system is included for temperature control of the conditioned gas.

11. The device according to claim 8 or 9, characterized in that The invention comprises an oxygen metering device and an input and output device (45; 145), wherein the input and output device (45; 145) has a display unit (46).

12. The device according to claim 11, characterized in that The display unit (46) is a touch screen (47).

13. The device according to claim 8 or 9, characterized in that A measuring device is included for blood gas measurement, wherein the blood gas is selected from the group consisting of carbon dioxide and oxygen.

14. The device according to claim 8, characterized in that Determine the at least one pressure difference approximation (dP Sch )include: Changing the nasal airflow (F) through the hose system and the nasal cannula within a predetermined time window nasal ); During this time window: (i) measuring the internal air pressure (P) in the medical device (20; 120) generated by the actuator (22) int );as well as (ii) measuring the internal airflow (F) in the medical device (20; 120) generated by the actuator (22) int ); For each nasal airflow (F nasal ) and the measured internal airflow (F int ), calculate the approximate pressure difference (dP Sch );as well as Stores approximate differential pressure (dP Sch ) and the associated internal airflow (F int ) for the applied hose system (17) and nasal catheter (16).

15. The device according to claim 14, wherein the nasal airflow (F nasal ).

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