Ventilation device

Abstract

Ventilation device (1) for ventilating a patient (47), with • a control unit (7), • an expiratory valve (3), • an inspiration valve (2), • an inspiratory pressure sensor (13), • an expiratory pressure sensor (13'), • a connection system (48) with an inspiratory supply line (91) for supplying respiratory gases to the patient (47) and with an expiratory supply line (92) for carrying respiratory gases away from the patient (47), • a connecting element (46) for connecting the patient (47) to the connection system (48), • a pressure measuring line (94) pneumatically coupled to the connecting element (48), • another pressure sensor (15) pneumatically coupled to the pressure measuring line (94), • wherein the inspiratory pressure sensor (13) is arranged in or on the inspiratory supply line (91) of the connection system (48), • wherein the inspiratory pressure sensor (13) is designed to detect an inspiratory pressure measurement value (13) and to provide the inspiratory pressure measurement value (13) to the control unit (7), • wherein the expiratory pressure sensor (13') is arranged in or on the expiratory supply line (92) of the connection system (48), • wherein the expiratory pressure sensor (13') is designed to detect an expiratory pressure measurement value (13') and to provide the expiratory pressure measurement value (13') to the control unit (7), • wherein the further pressure sensor (15) is designed to detect a pressure measurement value close to the patient and to provide the pressure measurement value close to the patient to the control unit (7), • wherein the control unit (7) is designed to control the inspiration valve (2) taking into account the inspiratory pressure measurement value (13) in order to provide an inspirational breathing gas mixture with an inspirational pressure level for the patient (47) via the inspirational supply line (91) of the connection system (48), • wherein the control unit (7) is designed to control the expiratory valve (3) taking into account the expiratory pressure measurement value (13') in order to set an expiratory pressure level via the expiratory supply line (92) of the connection system (48) for the patient (47), • wherein the control unit (7) is designed to carry out ventilation with a ventilation frequency of up to 150 respiratory cycles per minute (150 min -1 ) with a ratio of inspiration time T i to expiratory time T ein a range from 4 to 1 to 1 to 5 (I:E ratio from 4:1 to 1:5), • wherein the control unit (7) is designed to control at least the expiratory pressure level on the basis of the patient-near pressure measurement value by means of the inspiration valve (2) and the expiration valve (3) in such a way that the pressure level is assigned an HF oscillation with an HF ventilation frequency (17) as a variation in amplitude in a range of 3 Hertz to 20 Hertz (3 sec -1 up to 20 seconds -1 ) with and with a HF oscillation ratio (20) of HF-inspiration time HF-T i to HR-expiratory time HR-T e in a range of 1 to 1 to 1 to 3 (HF- I:E ratio of 1:1 to 1:3), wherein the control unit (7) is further designed to carry out a signal processing (1000) of the pressure measurement value close to the patient, wherein the control unit (7) when carrying out the signal processing (1000) • at least one property of the pressure measuring line (94) from a group of properties associated with pressure measuring lines and • at least one ventilation setting (21) or a change in the at least one ventilation setting (21) before and / or during operation of the ventilation device (1) from a group of ventilation parameters are taken into account, wherein the group of properties associated with pressure measuring lines comprises at least one of the following elements: o Length of the pressure measuring line (94), o Diameter of the pressure measuring line (94), o Material properties of the pressure measuring line (94), o Flow resistance of the pressure measuring line (94), o A line type, characterizing the length, the diameter, the material properties and / or a flow resistance of the pressure measuring line (94), wherein the group of ventilation settings (21) that can be set during operation of the ventilation device comprises at least one of the following elements: ◯ Ventilation rate (RR), ◯ Ratio of inspiration time to expiratory time (I:E ratio), ◯ Inspiration time (T i ), ◯ Expiratory time (T e ), ◯ inspiratory pressure level P insp , ◯ mean airway pressure P AW (19), ◯ HF pressure pressure level P HF (18), ◯ expiratory pressure level P exp , ◯ positive end-expiratory pressure (PEEP), ◯ HR ventilation rate (HR-RR) (17), ◯ set RF oscillation ratio (RF I:E ratio) (20), ◯ HR inspiratory time (HR-T i ), ◯ HR expiratory time (HR-T e ), ◯ inspiratory pressure plateau, ◯ inspiratory pressure gradient, ◯ Operating mode of a ventilation form, ◯ Patient type, characterized by age, sex, weight, gestational age, APGAR score, clinical picture of the patient (47).

Description

The present invention relates to a ventilation device for machine ventilation of a patient for use with an operating mode of ventilation forms with high-frequency ventilation.The ventilation device serves to supply the patient with breathing gases. High-frequency ventilation serves--especially in premature and newborn infants--for additional activation of the gas exchange in the lung. High-frequency ventilation allows improved ventilation of lung regions by superimposed alternating oscillation on the ventilation pressure. This superimposed alternating oscillation is generated by means of a modulation of a pressure amplitude of the ventilation pressure during high-frequency ventilation. Therefore, this superimposed alternating oscillation is often also referred to as modulated alternating oscillation. This results in an improved oxygen / carbon dioxide gas exchange into the patient's blood circulation without increasing the base level of the ventilation pressure. This particular form of ventilation is referred to as high-frequency ventilation, hereinafter abbreviated as RF ventilation. In contrast, conventional ventilation with a typical ventilation frequency in the range of around approximately 10 breaths per minute is often referred to as so-called conventional ventilation. The physiological respiration of an adult is typically in the range of 6 to 18 breaths per minute, which results in a respiration rate of 0.15 to 0.3 hertz. A premature infant or newborn infant breathes at 60 to 120 breaths per minute, corresponding to a breathing rate of 1 to 2 hertz. This superimposed or modulated frequency of the high-frequency ventilation, referred to below as RF frequency, is in the range of 5 to 20 oscillations per second, i.e. significantly above the physiological breathing frequencies. RF ventilation produces continuously at the output of the RF ventilator fluctuations in the pressure amplitude which follow the RF frequency which are superimposed on a physiological change from inspiration to expiration and an average airway pressure.As input parameters for the control and regulation of the operating mode of the HF ventilation, the HF frequency, the mean airway pressure, the pressure amplitude and the pressure difference, respectively, are often supplied to a control and regulating unit as a so-called "peak-to-peak pressure difference (peak-to-peak ΔP) of the HF oscillation and the I:E ratio, which corresponds to the ratio of the duration of inspiration to the duration of expiration. These input parameters frequency, pressure amplitude, mean airway pressure and I:E ratio are derived by the user from therapeutic considerations and from the constitution of the patient and can be set by the user as direct control values on an operating unit, and in another variant the control values can also be derived from other parameters.DE 28 31 313 A1 shows a device for assisting the breathing and / or breathing of a patient with the aid of a tracheal tube. Amounts of respiratory gas pass with an overpressure via a pressure reducer, a metering valve, into the tracheal tube. A frequency control device is configured to, in cooperation with a frequency valve and membrane control elements, inhalation chambers and exhalation chambers, form a pressure control for the metering valve in order to form periodically repeated inhalation phases for the ventilation.DE 10 2009 012 146 A1 discloses a method for controlling a ventilator with reduced excess gas, wherein a load situation of an exhalation valve is queried in a continuous sequence and a flow value is gradually reduced from a preset flow starting value, and wherein the flow value is increased again if a predetermined value of the load situation is exceeded.DE 10 2016 122 187 A1 shows a high-frequency generator for ventilation. The high-frequency generator has an inhalation connection and an exhalation connection. The high frequency generator comprises a vacuum source having a suction inlet. A pneumatically controlled exhalation valve may connect the exhalation port to the suction inlet. The control port of the exhalation valve can be pneumatically connected to the suction inlet or the source port via an electrically controlled exhalation control valve. In another embodiment, a pneumatically controlled inhalation valve connects the source connection to the inhalation connection and an electrically controlled inhalation control valve connects the control connection of the inhalation valve to the source connection or the suction inlet of the vacuum source.DE 600 28 532 T2 shows a device for high-frequency mechanical ventilation with an oscillator unit. The apparatus includes a flow controller configured to divide the volume of gas supplied by the oscillator unit between a distal end of a delivery conduit and an outlet to provide a predetermined inspiratory tidal volume for delivery to the patient's airways independent of the oscillator volume.DE 102006048680B3 describes a method for deriving the RF frequency and the pressure amplitude of the RF oscillation from a set tidal volume.WO2007142642 describes a method for controlling pressure fluctuations in the rhythm of an RF frequency for a ventilator.A ventilator for applying HF ventilation is described in DE 3417954A1, wherein a sinusoidal positive alternating pressure amplitude is applied to the patient supply line at the rhythm of the HF frequency by means of a generator in conjunction with a valve arrangement and a negative alternating pressure amplitude is applied by means of an ejector nozzle. The patient supply line connects the ventilator to the patient, in whose lung the pressure change fluctuation is then introduced by means of an endotracheal tube or a tracheostoma (invasive ventilation) or a breathing or breathing mask (non-invasive ventilation, NIV ventilation). The open-loop and closed-loop control unit converts the input parameters HF frequency, mean airway pressure, pressure amplitude and I:E ratio into the required actuating variables for the pressure and flow control and the actuation of the device components, such as, for example, ejector and valve arrangement.In order to generate a pneumatic pressure change fluctuation on the patient, an air volume must be displaced through the patient line to the patient and back and forth again. The patient supply line represents a dynamic pneumatic resistance for the supplied air quantity, which can be described by a low-pass filter. As a result, in order to supply a pressure change fluctuation to the patient, the flow speeds required for this purpose increase disproportionately with increasing frequency. In order to avoid additional pneumatic resistances and volumes in the gas supply line at the mouth of the patient and pressure drops resulting therefrom, sensor systems for detecting pressure and / or flow rate close to the patient are often dispensed with in the case of HF ventilation. According to the usual prior art, the pressure is measured via a pressure measuring line, by means of which the pressure level is transmitted from a pressure measuring location directly close to the patient, usually directly from the so-called Y-piece to a pressure sensor arranged in the ventilation device. Various disturbances and disturbance variables acting on the transmission from the outside, disturbances caused by the patient, as well as disturbances resulting from the operation and use of the ventilation device itself, are problematic in the transmission of pressure levels by means of a pressure measuring line.Thus, both at the beginning of the transmission from the patient's mouth, an interference variable can be injected into the transmission, which is then transmitted and propagated to the pressure sensor arranged in the ventilation device. As an example, a cough attack of the patient may be mentioned here; such a cough attack may then also be found in the measurement signal of the pressure sensor arranged in the ventilation device.Further examples which may be mentioned here are rapid pressure changes which occur during the respiration of the patient, whether they are brief pressure increases caused by a blockage of the respiratory gas feeds or, for example, rapid pressure fluctuations which occur by passive pressure relief valves and which can be exhibited in the measurement signal of the pressure sensor arranged in the respiration device. Further disturbances and interference variables result from the operation and use of the ventilation device itself, caused by ventilation frequency, HF frequency, time pattern of ventilation (I:E ratio, HF-I:E ratio) and other disturbances resulting therefrom and excited, for example in frequency ranges of the frequencies and their time pattern, as well as in frequency ranges of harmonics caused thereby.The present invention has for its object to specify a ventilation device which enables a determination of a pressure measurement value close to the patient, which measurement value is reduced by error influences.These and other objects are achieved by the enclosed independent patent claims, in particular by a ventilation device having the features of claim 1.Advantageous embodiments of the invention are evident from the dependent claims and are explained in more detail in the following description with partial reference to the figures.According to the aspects of the present invention, a control unit of a ventilator is designed in such a way that this control unit, when detecting and determining the pressure level at the Y-piece, uses a type of signal processing which can take account of the conditions of use and boundary conditions of the pressure measurement at the measurement site and / or also settings of the ventilator.The control unit takes into account when performing the signal processing• at least one property of the pressure measurement line;• at least one ventilation setting or a change of the at least one ventilation setting during operation of the ventilation device.An embodiment according to the invention is designed by a ventilation device for machine ventilation of a patient.The ventilation device according to the invention is preferably designed for so-called high-frequency ventilation (HF ventilation) or has an operating mode which allows the ventilation device to carry out HF ventilation alone or in combination with further components.The ventilation device has an exhalation valve, an inhalation valve, an inhalation pressure sensor, an exhalation pressure sensor, a further pressure sensor, a control unit, a connection system having an inhalation line for supplying breathing gases to the patient and an exhalation line for continuing breathing gases from the patient, a connection element and a pressure measurement line. The connecting element is designed as a so-called Y-piece and connects the inspiratory line and expiratory line close to the patient.The inspiratory pressure sensor is arranged in or on the inspiratory line of the connection system. The inspiratory pressure sensor is designed to record an inspiratory pressure measurement value and to provide the inspiratory pressure measurement value to the control unit.The expiratory pressure sensor is arranged in or on the expiratory line of the connection system. The expiratory pressure sensor is designed to record an expiratory pressure measurement value and to provide the expiratory pressure measurement value to the control unit.The pressure measurement line serves for the transmission and provision of a pressure level close to the patient directly close to the patient from the connecting element to the further pressure sensor arranged in the ventilation device. The pressure measurement line represents a pneumatic as well as a fluidic-pneumatic connection of the connecting element to the further pressure sensor arranged in the ventilation device.For this purpose, the pressure measurement line is connected at one end to the connecting element on the patient side, and the other end is pneumatically connected at the device side to the further pressure sensor arranged in the ventilation device.A pneumatic connection is understood in the sense of the present invention to mean a connection which enables a transport of a gas from a first location and to a second location.In addition, a pneumatic connection is understood in the sense of the present invention to mean a connection which enables a pressure level to be transmitted from a first location and to a second location. A fluidic connection is understood in the sense of the present invention to mean a connection which enables a transport of a fluid, i.e. a liquid or a gas or gas mixture, from a first location and to a second location. A fluidic-pneumatic connection is understood in the sense of the present invention to mean a connection which enables a transport of a fluid, i.e. a liquid or a gas or gas mixture, from a first location and to a second location or enables a transmission of a pressure level from the first location and to the second location.The further pressure sensor is designed to record a pressure measurement value close to the patient and to provide the pressure measurement value close to the patient to the control unit. In this case, the further pressure sensor detects the pressure level at the patient, that is to say the pressure level close to the patient, with the aid of the pressure measurement line. The pressure measuring line transmits the pressure directly present at the location of the patient at the connecting element in a pneumatic manner, as it were, in real time with the given propagation speed of the sound in the gas mixture, i.e. with the speed of sound currently given in the breathing gas mixture, to the further pressure sensor which is arranged in or near the breathing apparatus.The control unit is configured to control the inspiration valve taking into account the inspiratory pressure measurement value in order to provide an inspiratory pressure level to the patient via the inspiratory line of the connection system.The control unit is further configured to control the exhalation valve taking into account the exhalation pressure measurement value in order to provide an exhalation pressure level to the patient via the exhalation line of the connection system.The control unit is configured in such a way that, by means of the inspiration valve and the expiration valve, ventilation is set with a ventilation frequency in a range of up to 150 breathing cycles per minute (150 min -1) with a ratio of inspiration time duration to expiration time duration in a range of 4:1 to 1:5 (I:E ratio of 4:1 to 1:5).The control unit is further designed to actuate at least the expiratory pressure level on the basis of the pressure measurement value close to the patient by means of the inspiration valve and the expiration valve in such a way that an RF oscillation with an RF ventilation frequency as a variation in the amplitude in a range of 3 hertz to 20 hertz (3 sec -1 to 20 sec -1) with and with an RF oscillation ratio of RF inspiration time duration to RF expiration time duration in a range of 1 to 1 to 1 to 3 (RF-I:E ratio of 1:1 to 1:3) is superimposed on the pressure level. The superimposition with the HF oscillation by the control unit can take place at the expiratory and / or the inspiratory pressure level.According to the invention, the control unit is designed to carry out signal processing of the pressure measurement value close to the patient, wherein at least one property of the pressure measurement line from properties belonging to a group of pressure measurement lines and at least one ventilation setting or a change of the at least one ventilation setting from before and / or during operation of the ventilation device from a group of ventilation settings or ventilation parameters are taken into account by the control unit when carrying out the signal processing.The group of properties associated with pressure measurement lines comprises at least one of the following elements:◯ length of the pressure measuring line, diameter of the pressure measuring line, material properties of the pressure measurement line, a flow resistance of the pressure measurement line, A conductivity type, characterizing the length, the diameter, the material properties and / or a flow resistance of the pressure measurement line.The material properties and / or the conductivity type of the pressure measuring line-defined for different conductivity types-can each have, for example, details regarding flow resistance, material, and values for length, diameter, details regarding material properties (elasticity, flexibility, Shore hardness).The group of ventilation settings or ventilation parameters that can be adjusted during operation of the ventilation device comprises at least one of the following elements:◯ Respiration Frequency (RR),i) ratio of inspiration time duration (T to expiration time duration (T e) ( I:E ratio),i),e),◯ inspiratory pressure level P insp,◯ mean airway pressure P AW,HF,◯ expiratory pressure level P exp,◯ Positive End Expiratory Pressure (PEP),◯ RF Respiratory Frequency (RF-RR),◯ adjusted RF oscillation ratio (RF-I:E ratio),i),e),◯ inspiratory pressure plateau,◯ inspiratory pressure increase gradient,◯ operating mode of a form of ventilation, patient typus, characterized by age, sex, weight, gestational age, APGAR value, pathology of the patient.Taking into account at least one property of the pressure measurement line and at least one ventilation setting or changing at least one ventilation setting or ventilation parameters when performing the signal processing by the control unit offers advantages, for example, in that an adapted signal processing to the design of the ventilation device and the respectively given situation of use is made possible.Both patient-specific peculiarities (patient type) and ventilation settings specific to the individual patient, and the properties of the pressure measurement line used in each case in use for detecting the pressure measurement value close to the patient, can be advantageously taken into account according to the invention in the signal processing by the control unit. In particular, those ventilation settings or ventilation parameters which, during continuous operation and course of the ventilation device, have a continuous influence on the detection of the near-patient pressure measurement value can be taken into account in the effect on the detection of the near-patient pressure measurement value. These include, in particular, changes of ventilation settings to the ventilation frequency, I:E ratio, duration of inspiration and expiration, ventilation pressures (P insp, P exp, PEP), as well as HF ventilation frequency, HF-I:E ratio, duration of expiration and HF by the user.Because pneumatic events of greater temporal dynamics are also transmitted via the connection system, connection element and measurement line to further pressure sensors and are coupled into the pressure measurement values as a result of the superimposed HF ventilation, HF I:E ratio, HF in and HF exhalation time periods can be reflected in the measurement signals of the further pressure sensor, which is to be taken into account by the control unit during the signal processing. Taking into account the at least one property of the pressure measurement line and at least one ventilation setting or at least one ventilation parameter, or changing the at least one ventilation setting or at least one ventilation parameter, can be understood in the sense of the present invention as the possibilities explained in more detail below and also listed in various embodiments. One possibility of taking into account is given in that the ascertained pressure measured values are provided with corresponding identifiers, wherein the identifiers state somewhat about the quality of the pressure measured values during the detection during the operation of the ventilation device, i.e. the pressure measured values are provided with a quality index. With the aid of this quality index, the ventilation device can then use the pressure measurement values for monitoring the ventilation of the patient or possibly not use them when using these pressure measurement values corresponding to the index, or if appropriate verify the pressure measurement values if necessary with the aid of further information before a further use. Further possibilities result from a consideration in the form that interference variables present in the pressure measurement values can be removed, compensated or reduced, which can be designed with the aid of the following embodiments in practice for the control of the ventilation device with the aid of special signal processing.In a preferred embodiment of the ventilation device, interference signal components caused by propagations of pressure waves and reflections of pressure waves in the pressure measurement line are removed, reduced or compensated by the control unit when performing the signal processing.The propagation of pressure waves and reflections in the measurement line is also caused, inter alia, by the ventilation device performing ventilation.In this case, the selected form of ventilation with a ventilation frequency and a ratio of inspiration time duration to expiration time duration (I:E ratio) and in particular the RF ventilation frequency and the RF oscillation ratio (RF-I:E ratio) play a role in the excitation of pressure waves and reflections in the measurement line, among other things.The pressure waves are transmitted from the inspiratory feed line at the connecting element to and into the measurement line and thus also to the further pressure sensor.This preferred embodiment of the ventilation device offers the advantage, for example, that pressure measured values of the further pressure sensor corrected for disturbing variables can be used for the control by means of control and regulation of the ventilation by the ventilation device. Since the pressure measurement values of the further pressure sensor represent the pressure situation directly on the patient, the control or regulation of the ventilation by the ventilation device or by the control unit of the ventilation device on the basis of the pressure measurement values close to the patient can advantageously be carried out on the basis of these pressure measurement values.This enables a control of the inspiration pressure, as well as of the supplied volumes of breathing gases, adapted to the individual and currently present situation of the patient.According to a further preferred embodiment, the control unit is designed to use digital signal filtering when performing the signal processing. Digital signal filtering can be adaptively adjusted to boundary conditions of the operation of the ventilation device of the interference variables during the operation of the ventilation device. Known and customary types of digital signal filtering are FIR filters, IIR filters, Notch filters, and mathematical filter methods based on so-called Kalman filtering. The Kalman filter is a mathematical method with iterative estimates for selection of the filter parameters. The form of ventilation with ventilation frequency and ratio of inspiration time duration to expiration time duration (I:E ratio), RF ventilation frequency and RF oscillation ratio (RF-I:E ratio) selected for ventilation by the ventilation device can be taken into account in the design of the digital filter with regard to the filter parameters adapted and selected to the situation during operation of the ventilation device, such as frequency response, corner frequencies and order of the filter.In the sense of the present invention, the term "digital signal filtering" is also intended to include numerical methods, procedures and mathematical methods in which the control unit uses different forms of mathematical transformations or images of the pressure measurement values close to the patient when performing the signal processing. These include, for example, various forms of Fourier transformations (CWT, DFT, FFT, Z transformation, LaPla transformation), wavelet transformations, Sane Colton transformation.In a preferred embodiment of the ventilation device, the control unit is designed to include physical modelling when performing the signal processing, wherein the propagations of pressure waves and reflections of pressure waves in the pressure measurement line are also taken into account in the physical model.In the physical model formation, a physical model which describes the real physical and pneumatic conditions of the pressure measurement line as a transmission line with injections of pressure or pressure changes onto this transmission line, and an inversion of the physical model, a so-called inverted model, are applied. The physical model is formed from a forward wave and a return wave of a pressure pneumatically coupled into a transmission line or a pressure change into the pressure measurement line, which propagates from a line start at the patient to a line end of the measurement line in or at the ventilation device and is reflected at the line end. At or in the ventilation device, the measurement of the pressure level present at the patient takes place at the line end in order to determine a pressure measurement value close to the patient by the further pressure sensor.A pressure measurement value at the line end is used with the aid of the physical model formation with the physical model of the transmission line and an inverted model of the transmission line to determine a pressure level close to the patient, in which the interference signal components, which actually exist in the detected pressure measurement value in the measurement application and are based on superimpositions and reflections in the pressure measurement line, are reduced.The measurement of the pressure measurement value at the line end already measures superpositions of the incoming wave and the returning wave.The return wave corresponds to the reflection of the forward wave. The model takes into account a line end reflection factor and a line start reflection factor. The line end is assumed and modeled as a closed end, which corresponds to a reflection factor of 1. The lead start is assumed and modeled as an open end, which corresponds to a reflection factor of -1.In a preferred embodiment of the ventilation device, the generation and / or propagation of pressure waves and reflections of pressure waves in the pressure measurement line are to be taken into account with the physical model formation.In this case, the control unit is designed to remove, reduce or compensate the interference signal components caused by the generation and / or propagation of pressure waves and reflections of pressure waves in the pressure measurement line.In a preferred embodiment of the ventilation device, the generation and / or propagation of pressure waves and reflections of pressure waves in the pressure measurement line are taken into account in the physical model, which due to the provision of the inspiratory and expiratory pressure levels in the connection system and / or at the connection element act in the pressure measurement line and on the further pressure sensor and cause changes in the pressure measurement value close to the patient and in the time profile of the pressure measurement value close to the patient.In this case, the control unit is designed to remove, reduce or compensate for the interference signal components caused by the provision of the inspiratory and expiratory pressure levels in the connection system and / or on the connection element and propagating pressure waves and reflections of pressure waves in the pressure measurement line.In a preferred embodiment, a temperature and / or a composition of the inspiratory breathing gas mixture are taken into account in the physical model.This advantageously allows fine tuning of the physical model. In this case, the dependence of the speed of sound in different gas mixtures on the respective composition of the gas mixture and the dependence of the speed of sound on different temperatures of inhalation and exhalation can also be taken into account.In a preferred embodiment, properties associated with the pressure measurement line are taken into account in the physical model.Taking into account properties of the pressure measurement line makes it possible, for example, to incorporate different lengths, diameters, material and material properties, for example the elasticity of the pressure measurement line, into the physical model. This makes it possible for different pressure measuring lines to be used for different fields of application, adapted to the use situations in the hospital.In a preferred embodiment of the ventilation device, properties associated with the pressure measurement line are taken into account by the control unit when digital signal filtering is used. Taking into account properties of the pressure measurement line makes it possible, for example, to incorporate different lengths, diameters, material and material properties, for example the elasticity of the pressure measurement line in the embodiment of digital signal filtering.This makes it possible to achieve the possibility of using different pressure measuring lines for different fields of application, adapted to the situations of use in the hospital.In a preferred embodiment, properties associated with the connection system and / or the connection element are taken into account in the physical model. Taking into account properties of the connection system or of the connection element makes it possible, for example, to incorporate different lengths, diameters, material and material properties of an inspiratory ventilation tube, of an expiratory ventilation tube and also of the type of configuration of the connection element.The connecting element can be designed as a so-called Y-piece with or without an extraction connection (luer lock), as well as as as a nasal mask or tracheostoma. If these design options and the properties of the ventilation tubes are taken into account in the physical model, there are options that, with an adaptation in the physical model in the ventilation device, this ventilation device can be used in a manner adapted to different use situations in the hospital.In a preferred embodiment of the ventilation device, properties associated with the connection system and / or the connection element are taken into account by the control unit when digital signal filtering is used.Taking into account properties of the connection system or of the connection element makes it possible, for example, to incorporate different lengths, diameters, material and material properties of an inspiratory ventilation tube, of an expiratory ventilation tube and also of the type of configuration of the connection element. The connecting element can be designed as a so-called Y-piece with or without an extraction connection (luer lock), as well as as as a nasal mask or tracheostoma.If these design options as well as the properties of the ventilation tubes are taken into account when performing digital signal processing and signal filtering, there are options that, when performing signal processing and signal filtering in the ventilation device, this ventilation device can be used in a manner adapted to different use situations in the hospital.In a preferred embodiment of the ventilation device, a suction nozzle is arranged in the ventilation device.In a variant of this preferred embodiment, an operating state associated with the suction nozzle and / or at least one property of the suction nozzle are taken into account in the physical model. In a further variant of this preferred embodiment, the control unit takes into account the associated operating state and / or at least one property of the suction nozzle when using the digital signal filtering of the suction nozzle. Such a suction nozzle is often also referred to as an ejector.With the aid of the suction nozzle, a partial quantity of respiratory gas or of respiratory gas mixture is sucked out of the expiratory feed line away from the patient in the direction of the respiratory device. In the interaction of monitoring the exhalation valve by means of the control unit and the suction nozzle, an impression or modulation of the HF ventilation with HF ventilation frequency (HF-RR) and HF oscillation ratio (HF-I:E ratio) is made possible. In one embodiment, continuous suction with a constant partial amount of breathing gas or breathing gas mixture away from the patient can be implemented in practice, but embodiments can also be realized in which the suction nozzle can be controlled by means of a suction profile of a pattern that is variable over time and amount. The properties of the suction nozzle include, for example, suction power, suction quantity, suction profile, type of suction nozzle.These preferred embodiments of the ventilation device offer, for example, the following advantages that operating states of the suction nozzle, which include states of deactivation or deactivation, as well as the manner in which the operation with suction power, suction quantity or suction profile is carried out during the currently used ventilation by the ventilation device can be taken into account by the control unit. The suction power, the amount of suction or also the suction profile can be given by the type of suction nozzle.If, for example, the suction power or suction quantity or also the suction profile are changed during the execution of the ventilation, then if these changes can be included in the physical model or in the digital signal filtering, an adaptation and consideration in the signal processing of the further pressure sensor is possible.In a preferred embodiment of the ventilation device, a flow sensor close to the patient is arranged in the ventilation device or on or in the connecting element. In a variant of this preferred embodiment, at least one of the properties associated with the flow sensor close to the patient, such as flow resistance, volume, diameter, structural size, structural length or sensor type, is taken into account in the physical model. In a further variant of this preferred embodiment, the control unit takes into account, when digital signal filtering is used, at least one of the properties associated with the flow sensor close to the patient, such as flow resistance, volume, diameter, structural size, structural size, structural length or sensor type. These two variants of the preferred embodiments of the ventilation device with a flow sensor close to the patient offer advantages in determining the quantity of flow quantities which flow into and out of the patient's lung, since the flow sensor arranged on the connecting element is capable of directly capturing a balance between inhaled and exhaled flow quantities or gas quantities, as well as volumes. A flow sensor close to the patient thus makes it possible that no difference formation between an inspiratory and an expiratory flow sensor is required, so that possible error influences due to measurement inaccuracies of the inspiratory or expiratory flow sensor are also omitted. With regard to temporal resolution and time profile when detecting the flow rate, the flow sensor close to the patient is also advantageous directly on the connecting element on the patient. The flow sensor close to the patient also influences the influence of the respiratory gases or respiratory gas mixtures flowing in the inspiratory feed line in the manner of coupling pneumatic effects from the inspiratory feed line into the measurement line due to its properties and due to its presence alone.It is therefore advantageous that the physical model also takes into account the properties, such as flow resistance, volume, diameter, structural size, structural length or also the sensor type of the flow sensor close to the patient. Various types or sensor types of the flow sensor close to the patient for using ventilation are possible, for example pressure difference flow sensors, heat transport flow sensors, ultrasonic flow sensors.Depending on the sensor type, different conditions of design, size, diameter, volume, flow resistance result for consideration in the physical model or when digital signal filtering is used by the control unit.In a preferred embodiment of the ventilation device, a device for providing and carrying out a flushing of the pressure measurement line is arranged in the ventilation device. In a variant of this preferred embodiment, an operating state associated with the arrangement for providing and carrying out a flushing of the pressure measurement line and / or at least one property of the arrangement are taken into account in the physical model. In a further variant of this preferred embodiment, the control unit takes into account, when using digital signal filtering, an operating state associated with the arrangement for providing and carrying out a flushing of the pressure measurement line and / or at least one property of the arrangement. Arrangements for providing and carrying out a flushing of the pressure measurement line result in advantages with regard to hygienic requirements for the operation of the ventilation device with the pressure measurement line. With the aid of the arrangement for providing and carrying out a flushing of the pressure measurement line, the control unit is made possible to clean the pressure measurement line continuously or at regular time intervals by means of a flushing. In this case, a flow rate (flushing flow) in a range from 0.1 to 0.9 to liters per minute is conveyed by the ventilation device into the pressure measurement line in the direction of the patient. These preferred embodiments of the ventilation device provide an advantage, for example, that operating states of the arrangement for providing and carrying out a flushing of the pressure measurement line, which include states of deactivation or deactivation, as well as the manner of carrying out the operation with configuration of the flushing flow with respect to pressure level, delivery quantity or time profile of the flushing flow during the currently applied ventilation by the ventilation device can be taken into account by the control unit. An arrangement for providing and carrying out a flushing of the pressure measurement line can be realized, for example, by means of a delivery pump which is arranged in or on the ventilation device and can be activated and / or controlled by the control unit, for example as a piezoelectric pump.An alternative possibility consists in branching off a certain amount of gas from the gas supply of the ventilator by means of a metering device and thus forming the arrangement for providing and carrying out a flushing of the pressure measurement line.In the physical model, in particular the delivery quantity and, together with the delivery quantity, influences and / or changes of the pressure situation in the pressure measurement line, which influence the further pressure sensor in an advantageous manner, can be included in the physical model. These influences and / or changes of the pressure situation have an effect on the pressure waves running in and returning in the pressure measurement line in the physical model and thus also in the modeling of the inverted model. Therefore, consideration is advantageous in order to ensure the highest possible accuracy of the pressure measurement of the further pressure sensor.Also when using digital signal filtering, influences and / or changes in the pressure situation caused by the arrangement for providing and carrying out a flushing of the pressure measurement line, having an effect on the transmission properties of the pressure measurement line, can be taken into account for the filtering with regard to the time behavior.In a further preferred embodiment of the ventilator, the physical model is used as a cooperation according to the following formulae: with the parameters:Pupward, P forward, P meas, P' meas, P Prox, R closed, R open, G gain, G damping, G delay, G forecast, fdisturbformed.The physical model with a forward wave and a backward wave with reflections of coupled-in pressure or pressure changes into the pressure measurement line at the beginning and end of the line are used to determine a pressure level close to the patient, in which the interference signal components, which actually exist in the detected pressure measurement value in the measurement application and are based on superpositions and reflections in the pressure measurement line, are reduced. The proximal pressure level P prox given to the patient represents the pressure at the beginning of the line.The pressure level P meas measured by measurement at the further pressure sensor represents the pressure at the line end. The measurement of the pressure measurement value at the line end already measures superpositions of the incoming wave and the returning wave. The return wave corresponds to the reflection of the forward wave. The model takes into account a line end reflection factor and a line start reflection factor. The line end is assumed and modeled as a closed end, which corresponds to a reflection factor of 1. The lead start is assumed and modeled as an open end, which corresponds to a reflection factor of -1. The modeling takes into account a reflection factor R closed at the line end and a reflection factor R open at the line start. In this case, G damping, R open, R closed represent experimentally determined values which can be determined with the aid of an experimental setup consisting of a ventilation device, pressure measurement line, connection system, connection element, and optionally additionally or optionally with the connection and inclusion of flow sensor or suction nozzle close to the patient. The dynamic properties are taken into account as damping G Damping with a damping transmission behavior of the pressure measurement line being assumed.The propagation time of the signal on the pressure measurement line as a transmission line is assumed to be a delay time G delay in a known length of the pressure measurement line having a typical sound velocity.With the aid of formulas 1 and 2, the relationships between the pressure levels and the reflection factors R closed, R open for the pressure curve P forward of the incoming wave and for the pressure curve Pbackwardder returning wave can be described. For the application of the model, the path with the incoming wave is now inverted to determine the measured variable P prox from the measured variable P meas for the subsequent provision of the pressure level P prox which is reduced by interference signal components, and the inverted model is thus formed.In the inverted model, the attenuation G damping is set for the pressure signal Pbackwardof the returning wave. In the inverted model, a gain G gain is set for the pressure signal P forward of the incoming wave. At the line end, the attenuated, incoming wave is already obtained in the inverted model as measured value P' meas, in correspondence with the pressure measured value P meas. To estimate the given pressure P prox at the line start, the measured value P' meas is weighted in the path of the returning wave of the inverted model according to formula 3 with the inverse function of the attenuation as the gain G gain.To map the dynamic transmission properties in the inverted model, the return wave is delayed by the delay time G delay. Assuming a periodic RF ventilation frequency as the basis of an interference signal excitation with a frequency f disturb at the start of the line and with interference signal detection at the end of the line and assuming that neither the periodicity of the interference signals nor the interference signals themselves do not change significantly from period to period, an estimated delay time G forecast is set, which results according to formula 4 as the period duration 1 / f disturb of the interference signal excitations minus the delay time G delay. Thus, according to formula 5, the pressure P prox at the beginning of the line, given proximally to the patient, can be determined as superposition of the back-calculated incoming wave and the return wave reflected at the end of the line. The control unit is designed to determine a corrected pressure measurement value close to the patient using these formulas and to take into account the determined pressure measurement value close to the patient during the control of the inspiration valve and the expiration valve. Thus, using the model inverted according to the above explanations and assumptions, the control unit can use the control unit to determine the pressure P prox at the beginning of the line, which pressure is given proximally to the patient, and can be used for controlling, controlling and / or regulating ventilation, in particular HF ventilation. In particular by the control unit controlling the inhalation valve and exhalation valve, a pressure situation which is applied proximally to the patient is thus made possible.The present invention, in cooperation with a suction nozzle (ejector) optionally arranged in or on the ventilation device at the end of the expiratory feed line of the connection system and / or a flow sensor close to the patient optionally arranged on the connection element, makes it possible to provide ventilation very well matched to the individual patient, in particular RF ventilation very well matched. A significant reduction of interference signals induced by HF ventilation to the pressure measurement with the further pressure sensor is achieved by applying the described methodology based on the physical modelling with the associated formulae 1 to 5. The described preferred embodiments of the ventilation device with digital signal filtering or physical modelling in the signal processing of the further pressure sensor taking into account the propagations of pressure waves and reflections of pressure waves in the pressure measurement line of the further pressure sensor offer substantial advantages in that no attachment of a pressure sensor close to the patient is necessary, so that neither the overall size nor the weight of an additional sensor adversely affect the access to the patient for the clinical personnel or the situation of the patient.In addition, the omission of an additional sensor in the mouth / nose / face region of the patient also means that no otherwise necessary elements for energy supply, energy interfaces, data lines or data interfaces are to be guided close to the patient, which in turn offers advantages with regard to access to the patient, as well as advantages in the design of the patient safety, in particular also with regard to electrical safety or also electromagnetic compatibility.Table 1 and Table 2 show lists with parameters and / or setting variables, as well as properties of the pressure measurement line, which can be taken into account in the wave model to reduce the interference signal components in the measurement signal of the pressure measurement close to the patient or can at least partially also be used in adaptive signal filtering. Some information on estimates regarding the effect of the inclusion of parameters, adjustment variables or properties of the pressure measurement line is entered in the lists in the form of effects. This contains estimated data in the form of a simplified three-stage scaling o, +, ++, which make it possible to estimate the extent to which improvements can be achieved in each case by the respective inclusion of the parameters or setting variables or properties of the pressure measurement line. The following Table 1 shows a list of exemplary parameters and adjustment variables which can be given during operation of a ventilation device. In Table 1, exemplary estimates are given as to which effects result when the listed parameters and setting variables are taken into account, in each case when wave model or adaptive signal filtering is used with a view to reducing error influences in the determination of the pressure measurement value close to the patient. Table 1 Table 1Respiration Frequency (RR)++++Ratio of Inspiration Duration (T i) to Expiration Duration (T e) ( I:E Ratio)+++Inspiration Time Period (T i)+++Exhalation period (T e)+++P insp00P exp00Positive End Expiratory Pressure (PEP)00RF Oscillation Ratio (RF-I:E Ratio)++++RF Respiratory Frequency (RF-RR)+++Breathing gas temperature0+Breathing Gas Composition0+Breath Gas Moisture0+FiO 20+The following Table 2 shows a list of exemplary properties of the pressure measurement line. In Table 2, exemplary estimates are given as to which effects result when considering the listed properties of the pressure measurement line, in each case when applying wave model or adaptive signal filtering with a view to reducing error influences in the determination of the pressure measurement value close to the patient. Table 2 Table 2Length of the Pressure Measurement Line+++Diameter of the Pressure Measurement Line+++Volume of the Pressure Measurement Line+++Materialeigenschaften0+Flow Resistance+++Diameter of the endotracheal tube0+Suction nozzle (ejector) (type, suction power, suction quantity, suction profile)0+Flow sensor close to the patient (type, diameter, volume)0+Flushing flow (delivery quantity, pressure level)0+Patient properties (airway resistance, airway elasticity)00The present invention will now be explained in more detail with the aid of the following figures and the associated descriptions of figures without restrictions of the general inventive idea. Exemplary embodiments of the invention are shown in the figures and explained in more detail below. The following are shown: FIG. 1 shows a schematic overview of the components of a ventilator for HF ventilation FIGS. 2 a, 2 b show wave models of a pneumatic transmission line FIG. 2 cshows a schematic flow chart of a signal processing according to FIGS. 2 aand 2 b, FIG. 3a is a block diagram of adaptive signal filtering, FIG. 3 bshows a flow chart of adaptive signal filtering according to FIG. 3 a.FIG. 1 shows a schematic overview of the components of a ventilation device 1 which is equipped for carrying out RF ventilation.The ventilation device 1 is designed for high-frequency ventilation and consists of the components:an inspiration valve 2, an expiration valve 3, a suction nozzle 4, an input unit 5, a control and regulating unit 7, a gas mixing unit 8, a gas metering unit 9, a flow regulation 10, a flow measurement 11, a pressure regulation 12, an inspiration pressure measurement 13, an expiration pressure measurement 13', a further pressure sensor 15, a valve control 14, an inspiration gas connection 91, an expiration gas connection 92 and a gas outlet 93. Furthermore, a control variable input 6 is present, by means of which the control variables 17, 18, 19, 20 relevant for the high-frequency respiration reach the pressure regulation 12, the flow regulation 10 in the control and regulating unit 7. The patient 47 is connected to the ventilation device 1 via an inspiratory gas connection 91 with inspiratory feed lines and an expiratory gas connection 92 with expiratory feed lines of a connection system 48 as feed lines, in this case via a hose system. The exhalation air is sucked from the patient 47 via a suction nozzle 4 (ejector) out of the feed lines 48 into the exhalation gas connection 92 and escapes to the environment via a gas outlet 93. The further pressure sensor 15 is connected to the ventilation device 1 by means of a pressure measurement line 94 on a connecting element 46, the so-called Y-piece, which connects the two supply lines at a location 49 close (proximal) to the patient 74, and is coupled pneumatically.By means of the pressure measurement line 94, a pressure level is conducted from the patient 47 to the further pressure sensor 15 and detected by the latter by measurement technology and provided to the control unit 7. The pressure measurement line 94 transmits the pressure present directly at the location 49 of the patient 47 in a pneumatic manner, as it were, in real time with the propagation speed of the sound in the gas mixture, i.e. with the speed of sound actually present in the breathing gas mixture, to the further pressure sensor 15 which is arranged in or near the breathing apparatus 1. Typical lengths of the usually and preferably flexible or elastic pressure measuring line 94 are 500 mm to 3000 mm, typical inner diameters of the pressure measuring line 94 are in the range from 0.7 mm to 7 mm. The further pressure sensor 15 serves for a pressure measurement close to the patient with detection of the pressure situation, caused by the high-frequency ventilation, of an actual value of the mean airway pressure directly on the patient 47. the pressure measurement close to the patient thus represents, as it were, a type of "pneumatic remote measurement" of a respectively currently given pressure in the feed line 48 directly on the patient 47 during the execution of mechanical ventilation by the ventilation device 1.The input unit 5 for parameter input is combined with a user interface and represents the manipulated variable input 6 for at least four manipulated variables 17, 18, 19, 20 required for setting the HF ventilation.The at least necessary four control variables 17, 18, 19, 20 for carrying out HF ventilation are:• RF Respiratory Frequency (RF-RR) 17,• the RF pressure amplitude 18,• the desired mean airway pressure P AW19 and• the RF oscillation ratio (RF-I:E) 20.The RF pressure amplitude 18 is usually indicated in the form of a peak-to-peak value (Ull), for example an analog or digital voltage signal which characterizes a pressure difference ΔP. These control variables serve as setpoint specifications for carrying out the HF ventilation by the ventilation device. The flow control 10, the pressure control 12 and the manipulated variable input 6 are connected closely to the control unit 7. The control unit 7 is provided to process the data and measured values of the pressure sensors 13, 13', 15 and the flow sensors 11 and to include them in the ventilation device 1 when performing control and regulating tasks. The data and measured values are supplied and provided by means of data lines in the ventilation device 1 and in particular to the control unit 7; for reasons of clarity, some of the signal and data lines of the ventilation device 1 are shown by way of example in FIG. 1, but are not provided individually with associated reference numerals. The control unit 7 transmits the control commands to the valve control 14 and receives the setpoint specifications 21 from the input unit 5. the valve control 14 sets the inspiratory and expiratory ventilation pressures and flow rates required for ventilation on the one hand and for HF ventilation on the other hand. For the further pressure sensor 15 for measuring pressure close to the patient, a signal processing unit 16 is arranged in the control unit 7, which is designed and provided to clean the measured pressure values P meas120 of the further pressure sensor 15 for measuring pressure close to the patient from interference signal components. The interference signal components of the pressure measurement values P meas120 of the further pressure sensor 15 for the pressure measurement close to the patient are substantially caused by the pressure changes in the feed lines 48 to the patient 47 caused by the RF ventilation, which pressure changes propagate into the pressure measurement line 94 as far as the further pressure sensor 15 and represent themselves as interference signals in the measurement signal P meas120 of the further pressure sensor 15 for the pressure measurement close to the patient.These pneumatically caused superimpositions in the pressure measurement line 94 cause interference signal components in the measurement signal of the further pressure sensor 15 for the near-patient pressure measurement, inter alia based on multiples (harmonics) of the set RF ventilation frequency 17, as well as excited by the set RF oscillation ratio 20 of the high-frequency ventilation. The signal processing unit 16 is designed to reduce the interference signal components in the measurement signal at the further pressure sensor 15 of the pressure measurement close to the patient, knowing the type and manner of the pneumatic excitations that are pneumatically effective in the pressure measurement line 94 and taking into account properties of the pneumatic system of the pressure measurement line 94. The properties of the pressure measurement line include, for example, length, diameter, material properties or flow resistance of the pressure measurement line 94. in addition to the set HF ventilation frequency 17 and the set HF oscillation ratio 20, further parameters and / or set variables can also have an additional influence on the interference signal components, such as, for example, ventilation frequency (RR), ratio of inspiration time duration to expiration time duration (I:E ratio), inspiration time duration (T i), expiration time duration (T e), inspiration and expiration pressure levels P insp, P exp, positive end expiratory pressure (PEP).The signal processing unit 16 can perform an adjusted manner of signal processing by incorporating knowledge of the properties of the pressure measurement line 94 and the manner of pneumatic excitation.Such signal processing can be carried out, for example, by adaptive signal filteringMore specifically, FIGS. 3 a, 3 b, 4, 5 or else including a mathematical modelDetailed in FIGS. 2 a, 2 b, 2 c, 4, 5 and the interference signal components in the measurement signal of the pressure measurement close to the patient are reduced at the further pressure sensor 15. The mathematical model (wave model) describes the manner of propagation and reflection and the associated time characteristics of pressure waves in the pressure measurement line 94 from the patient 47 to the further pressure sensor 15. The signal processing unit 16 provides, for example when using the mathematical models 100, 200 (FIGS. 2 a, 2 b, 2 c) or when using digital filters 400 (FIGS. 3 a, 3 b), an output signal P prox210, 2100 which is reduced by the interference signal components and is used by the control unit 7 and by the valve control 14 for carrying out the RF ventilation in the ventilation device 1.FIG. 2 ashows a physical model 100 of a pneumatic transmission line as a block diagram. FIG. 2 bshows an inverted model 200 of the pneumatic transmission line according to FIG. 2 ain block diagram form. Like components in Fig. 1 and in Figs. 2a, 2b and 2c are denoted by like reference numerals in Figs. 1, 2a, 2b and 2c. The physical models 100, 200 are now explained in more detail and described jointly in function and relationship with respect to one another below with reference to FIGS. 2 a, 2 band 2 c. The transmission line in the physical model 100 and the inverted 200 model physically simulates the pressure measurement line 94 of FIG. 1. The line start 941 of the transmission line in the models 100, 200 is assumed to be the location 49 (FIG. 1 ) on the patient 47 (FIG. 1 ), at which the pressure measurement line 94 (FIG. 1 ) is pneumatically coupled to the feed line 48 (FIG. 1 ) directly close to the patient 47 (FIG. 1 ). The line end 942 of the transmission line in the models 100, 200 is assumed to be the location of the further pressure sensor 15 (FIG. 1 ) in the ventilation apparatus 1 (FIG. 1 ), as the location at which the pressure measurement line 94 (FIG. 1 ) provides the pressure level given on the patient 47 (FIG. 1 ) for the measurement of a pressure measurement value close to the patient by the further pressure sensor 15 (FIG. 1 ). The proximal pressure level P prox110 given on the patient 47 (FIG. 1 ) represents the pressure at the line start 941 in the model 100.The pressure level P meas120 measured at the further pressure sensor 15 (FIG. 1 ) represents the pressure at the line end 942 in the model 100. The models 100, 200 each have upper paths 130, 230 and lower paths 140, 240. The upper paths 130, 230 each form a forward wave and the lower paths 140, 240 each form a backward wave in the models 100, 200 gradually. The pressure measurement value P meas120 at the line end 942 is used with the aid of the models 100, 200 explained below to determine a pressure level P prox210 close to the patient, in which the interference signal components which actually exist in the detected pressure measurement value P meas120 in the measurement application and are based on superimpositions and reflections in the pressure measurement line 94 (FIG. 1 ) are reduced. The measurement of the pressure measurement value P meas120 at the line end 942 already measures overlaps of the incoming wave 130 and the returning wave 140. The superimpositions are pictorially represented in the models 100, 200 for the sake of simplicity as summation points at the pressure measurement values or pressure levels 110, 120 210, 220. The return wave 140 corresponds to the reflection of the forward wave 130. The model 100 takes into account a reflection factor R closed350 at the line end 942 and a reflection factor R open300 at the line start 941. The line end is assumed and modeled as a closed end, which corresponds to a reflection factor of 1. The lead start is assumed and modeled as an open end, which corresponds to a reflection factor of -1.With the aid of Formula 1 and Formula 2, the relationships between the pressure levels 110, 120 and the reflection factors 300, 350 for the pressure profile P forward111 of the incoming wave 130 and for the pressure profile Pbackward121 of the returning wave 140 can be described.The dynamic properties are taken into account in the transfer functions as attenuation G Damping500. The signal propagation time is taken into account in the models 100, 200 by assuming a delay time G delay600 at a known length of the pressure measurement line 94 (FIG. 1 ) with a typical sound velocity in air at standard standard conditions (20° C., 1013 HPa) of 343 ms -1. No further information about the real measured value of the measured variable P prox120 is available. For the application of the model 100, in order to determine this measured variable P prox120 from the measured variable P meas110 for the subsequent provision of the pressure level P prox210 close to the patient, which pressure level is reduced by interference signal components, the upper path 130 is now inverted with the incoming wave and the inverted model 200 is thus formed. The inverted model 200 is shown in FIG. 2 b. A damping transmission behavior of the pressure measurement line 94 (FIG. 1 ) is assumed. In the inverted model 200, the attenuation G damping500 is set for the pressure signal of the returning wave 240. In the inverted model 200, a gain G gain700 is set for the pressure signal of the incoming wave 230. At the line end 942, the attenuated, incoming wave 230 is already obtained in the inverted model 200 as measured value P' meas220, in accordance with the pressure measured value P meas120 in the model 100. In order to estimate the given pressure P prox210 at the line start, the measured value P' meas220 is weighted in the path of the incoming wave 230 of the inverted model 200 according to Formula 3 with the inverse function of the attenuation as the gain G gain700.To map the dynamic transmission properties, the return wave 240 is delayed by the delay time G delay600. in the inverted model 200. The incoming wave 230 would have to be delayed in the inverted model 200 by an equivalent of a "inverse function of the propagation time".Since a mapping of the "inverse function of the travel time" would correspond to a prediction in the future, which cannot be mapped with the methodology of the physical model 100 and the inverted model 200, an estimated delay time G forecast800 is set on the assumption of a periodicity of the RF ventilation frequency as the basis of an interference signal excitation with a frequency f disturb at the line start and interference signal detection at the line end and on the assumption that neither the periodicity of the interference signals nor the interference signals themselves do not change significantly during the course of the ventilation from period to period, which delay time G results according to the formula 4 as the period duration 1 / f disturb900 of the interference signal excitations minus the travel time G delay600.Thus, according to Formula 5, the pressure P prox210 at the beginning of the line 941, given proximally to the patient 47 (FIG. 1 ), can be determined as superposition of the back-calculated incoming wave 230 and the back-running wave 942 reflected at the end of the line 942 according to Formula 5.Thus, with the use of the inverted model 200 according to the above explanations and assumptions, a determination of the pressure P prox210 at the beginning of the line 941, which is given proximally to the patient 47 (FIG. 1 ), can be carried out by means of the control unit 7 (FIG. 1 ) and can be used for the control, control and / or regulation of the HF ventilation. In particular by controlling the inhalation valve 2 (FIG. 1 ) and the exhalation valve 3 (FIG. 1 ) by the control unit 7 (FIG. 1 ), an HF ventilation that is matched very well to the individual patient 47 (FIG. 1 ) is thus made possible by the control unit 7 (FIG. 1 ) to the pressure situation 49 given proximally on the patient 47 (FIG. 1 ) in cooperation with the suction nozzle (ejector) 4 (FIG. 1 ), since the interference signals indicated by the HF ventilation can be significantly reduced to the pressure measurement with the further pressure sensor 15 (FIG. 1 ) by the application of the described methodology based on the models 100, 200 and associated formulae 1 to 5.In measurement tests with measurement lines 94 (FIG. ) having an overall length in the range from 1500 mm to 2500 mm and inner diameters in a range from 1.5 mm to 3 mm, good results in the reduction of the interference signal components could be achieved, for example, with values in the range from 0.5 to 1.0 for the attenuation G damping500 and with values in the range from 3.5 milliseconds to 7.5 milliseconds for the delay time G delay600.Including the periodicity of the HF ventilation frequency (HF-RR) in the range from 5 sec -1 to 20 sec -1 as well as including the HF oscillation ratio (HF-I:E) in a range from 1:1 to 1:3 and the excited frequency components f disturb900 of the injected interference signal components respectively associated therewith in the pressure measurement of the further pressure sensor 15 (FIG. 1 ), by means of formulas 1 to 5, for example, an adaptation of the signal processing 16 (FIG. 1 ) of the signals of the further pressure sensor 15 (FIG. 1 ) in the control unit 7 (FIG. 1 ) to changes of setting variables and / or input parameters carried out by the user is made possible. Table 1 of the general description lists examples of adjustment variables and / or input parameters.In addition, values for length and inner diameter or material properties of the pressure measurement line 94 (FIG. 1 ) that deviate from the above range information can also be incorporated into the values used in the application of the models 100, 200 for the attenuation G damping500 and the delay time G delay600, and also the amplification G gain700 by means of the formulae 1 to 5 in the model formation. In principle, such an adaptation of delay time G delay600, G damping500, gain G gain700, G forecast800, f disturb900 on the basis of at least one of the setpoint assignments 21 (FIG. 1 ), such as, for example, the parameters 17, 18, 19, 20 (FIG. 1 ), can be carried out by means of adaptation of the models 100, 200 during the signal processing 16 (FIG. 1 ) by the control unit 7 (FIG. 1 ). Table 2 of the general description lists further examples of properties of the pressure measurement line 94 (FIG. 1 ).FIG. 2 cshows a schematic flow chart of a routine 1000 for an application of signal processing based on the models 100, 200 according to FIGS. 2 aand 2 b. After a START 1100 with loading of presets for input parameters 1101 with properties of the pressure measurement line 94 (FIG. 1 ), the currently set RF ventilation frequency 17 and the set RF oscillation ratio 20 are supplied as input parameters to the routine 1000 as RF ventilation parameters 1102 in a preparation step 1110. Optionally, a further preparation step 1111 can be carried out, in which current data 1103 for length and inner diameter or material properties of the currently used pressure measurement line 94 (FIG. 1 ) are supplied as further input parameters to the routine 1000. The current data 1103 can be supplied, for example, via an input field which is edited for use on the ventilator 1 (FIG. 1 ), another possibility being a data connection to a superordinate system, a reading of data from a data memory (RFID chip) arranged in or on the pressure measurement line 94 (FIG. 1 ).A further possibility is given in that a maneuver for determining material properties of the pressure measurement line 94 (FIG. 1 ) can be carried out by the ventilation device 1 (FIG. 1 ). A comparison 1200 follows whether the newly supplied input parameters deviate from the presets. If "yes", initialization 1300 is performed, if "no", then initialization 1300 is skipped.During the initialization 1300, the inverted model 200 according to FIG. 2 bis adapted 1333 to the currently set RF ventilation frequency 17 and the set RF oscillation ratio 20, as well as to other modified input parameters, such as the length or inner diameter of the pressure measurement line 94 (FIG. 1 ).These adjustments in model 200 affect both attenuation G Damping500 ( 2a, 2b) in terms of dynamic characteristics, as well as gain G gain700 ( 2a, 2b) and estimated delay time G forecast800 ( 2a, 2b). Subsequently, in a signal detection and signal processing step 1400, the signals P meas120 of the further pressure sensor 15 (FIG. 1 ) are continuously read in, followed by continuously performed application of the inverted model 200 with reduction of the interference signal components superimposed on the signals P meas120 of the further pressure sensor 15 (FIG. 1 ), and with continuously updated provision of an output signal 2100 as a result of the routine. The output signal 2100 indicates a pressure P prox210. given proximally to the patient 47 (FIG. 1 ). When RF ventilation is ended at the ventilation device 1 (FIG. 1 ), the routine 1000 comes to an end 1500.FIG. 3 ashows an exemplary block diagram of adaptive signal filtering 400. The block diagram of the adaptive signal filtering 400 with input signal x(n) 401 and output signal y(n) 402 has, as typical elements, a first weighting factor b 0403, a second weighting factor b 1404, a timer T 405 and a summation element 406 of a linear, time-invariant, time-discrete system, which can be described with the aid of formula 6 in general form for a sequence of samples nThe input signal x(n) 401 corresponds to the measured pressure value P meas120 ( FIG. 1 ) detected by measurement technology by the further pressure sensor 13 (FIG. 1 ), and the output signal y(n) 402 corresponds to the proximal pressure P prox210 ( FIG. 1 ) directly on the patient 47 (FIG. 1 ). The graphic elements 407, 408 indicate the adaptation of the weighting factors b 0403, b 1404, including of the timer T 405 on the basis of the HF ventilation frequency (HF-RR) 17 (FIG. 1 ) and / or the HF oscillation ratio (HF-I:E) 20 (FIG. 1 ). In principle, such an adaptation of the weighting factors b 0403, b 1404 and / or timer T 405 can be carried out on the basis of at least one of the setpoint assignments 21 (FIG. 1 ), such as the parameters 17, 18, 19, 20 (FIG. 1 ), for example, by means of the adaptive signal filtering 400 by the control unit 7 (FIG. 1 ).FIG. 3 bshows a schematic flow chart of a routine 4000 for an application of signal processing with adaptive signal filtering. Like components in Figures 1, 2a, 2b and in Figures 3a and 3b are denoted by like reference numerals in Figures 1, 2a, 2b, 2c, 3a, 3ba and 3b.After a START 4100 with loading of presets for input parameters 4101 with properties of the pressure measurement line 94 (FIG. 1 ), the currently set RF ventilation frequency 17 and the set RF oscillation ratio 20 are supplied as input parameters to the routine 4000 as RF ventilation parameters 4102 in a preparation step 4110. Optionally, a further preparation step 4111 can be carried out, in which the routine 4000 is supplied with current data 4103 for length and inner diameter or material properties of the currently used pressure measurement line 94 (FIG. 1 ) as further input parameters.The current data 4103 can be supplied, for example, via an input field which is edited for use on the ventilator 1 (FIG. 1 ), another possibility being a data connection to a superordinate system, a reading of data from a data memory (RFID chip) arranged in or on the pressure measurement line 94 (FIG. 1 ).A comparison 4200 follows whether the newly supplied input parameters deviate from the presets. If "yes", initialization 4300 is performed, if "no", then initialization 4300 is skipped.During initialization 4300, digital filter 400 according to FIG. 3 ais adapted 4333 to currently set RF ventilation frequency 17 and set RF oscillation ratio 20, as well as to other modified input parameters, such as the length or inner diameter of pressure measurement line 94 (FIG. 1 ).These adaptations in the digital filter 400 affect both the dimensioning of the weighting factors b 0403, b 1404 ( FIG. 3 a) and the dimensioning of the timer T 405 (FIG. 3 a). Subsequently, in a signal detection and signal processing step 4400, the signals P meas120 of the further pressure sensor 15 (FIG. 1 ) are continuously read in, followed by continuously implemented application of the digital filter 400, with reduction of the interference signal components superimposed on the signals P meas120 of the further pressure sensor 15 (FIG. 1 ), and with continuously updated provision of an output signal 2100 as a result of the routine.The output signal 2100 indicates a pressure P Prox210. given proximally to the patient 47 (FIG. 1 ). Upon completion of RF ventilation at ventilator 1 (FIG. 1 ), routine 4000 comes to an end 4500. As an alternative to the filter described with formula 6 in general form, which describes a configuration as an FIR filter (FIR=finite impulse response), an IIR filter (infinite impulse response) can also be used for digital signal filtering.List of reference characters1 Ventilation device 2 Inhalation valve 3 Exhalation valve 4 Suction nozzle, ejector 5 Input unit for parameter input 6 Manipulated variable input 7 Control unit, control, regulation of ventilation 8 Gas mixing unit 9 Gas metering unit 10 Flow regulation 11 Flow measurement 12 Pressure regulation 13 Pressure sensor inspiratory 13' Pressure sensor expiratory 14 Valve control 15 Further pressure sensor close to the patient pressure measurement 16 Pressure signal processing 17, 18, 19, 20 Manipulated variables 21 Setpoint specifications 46 Connecting element (Y piece) 47 Patient 48 Connecting system, feed lines / hose system 49 Patient, location on the patient 91 Inspiratory feed line, inspiratory gas connection 92 Expiratory feed line, Expiratory gas connection 93 Gas outlet 94 Pressure measuring line 100 Block diagram physical model 110 Proximal pressure level P prox in physical model 111 Pressure profile P forward of the incoming wave 120 Pressure level P meas in physical model 130 Incoming wave in physical model 140 Returning wave in physical model 121 Pressure profile Pbackward returning wave 200 Block diagram inverted model 210 Proximal pressure level P prox in inverted model 220 Pressure level P' meas in inverted model 230 Incoming wave in inverted model 240 Returning wave in inverted model 300 Reflection factor R open at the beginning of the line 350 Reflection factor r closed at the line end 400 of the digital filter 401 input signal of the digital filter 402 output signal of the digital filter 403, 404 weighting factors 405 timer 406 summation element 407, 408 elements for adapting the digital filter 500 dynamic properties attenuation G Damping600 delay time G delay700 gain G gain800 estimated delay time G forecast941 line start of the pressure measurement line 942 line start of the pressure measurement line 1000 routine 1100 START 1101 input parameter 1102 HF ventilation parameter 1103 data of the currently used pressure measurement line 1110 preparation step 1111 further preparation step 1200 comparison 1300 initialization 1400 signal detection and signal processing step 1500 end, STOP, Stop 2100 Output signal 4100 START 4101 Input parameter 4102 HF ventilation parameter 4103 Current data of the pressure measurement line 4110 Preparation step 4111 Further preparation step 4200 Comparison 4300 Initialization 4400 Signal acquisition and signal processing step 4500 End, STOP, Stop

Claims

A ventilation device (1) for ventilating a patient (47), comprising • a control unit (7), • an exhalation valve (3), • an inhalation valve (2), • an inhalation pressure sensor (13), • an exhalation pressure sensor (13'), • a connection system (48) with an inhalation feed line (91) for feeding respiratory gases to the patient (47) and with an exhalation feed line (92) for conveying respiratory gases from the patient (47), • a connection element (46) for connecting the patient (47) on the patient side to the connection system (48), • a pressure measurement line (94) pneumatically coupled to the connection element (48), • a further pressure sensor (15) pneumatically coupled to the pressure measurement line (94), • wherein the inspiratory pressure sensor (13) is arranged in or on the inspiratory feed line (91) of the connection system (48), • wherein the inspiratory pressure sensor (13) is designed to detect an inspiratory pressure measurement value (13) and to provide the inspiratory pressure measurement value (13) to the control unit (7), • wherein the expiratory pressure sensor (13') is arranged in or on the expiratory feed line (92) of the connection system (48), • wherein the expiratory pressure sensor (13') is designed to detect an expiratory pressure measurement value (13') and to provide the expiratory pressure measurement value (13') to the control unit (7), • wherein the further pressure sensor (15) is designed for detecting a pressure measurement value close to the patient and for providing the pressure measurement value close to the patient to the control unit (7), • wherein the control unit (7) is designed to control the inspiration valve (2) taking into account the inspiration pressure measurement value (13) in order to provide an inspiration breathing gas mixture with an inspiration pressure level via the inspiration feed line (91) of the connection system (48) for the patient (47), • wherein the control unit (7) is designed to control the expiration valve (3) taking into account the expiration pressure measurement value (13') in order to set an expiration pressure level via the expiration feed line (92) of the connection system (48) for the patient (47), • wherein the control unit (7) is designed, by means of the inspiration valve (2) and the expiration valve (3), a respiration with a respiration frequency of up to 150 breathing cycles per minute (150 min -1) with a ratio of inspiration time duration T i to expiration time duration T e in a range of 4:1 to 1:5 (I:E ratio of 4:1 to 1:5) is set, • wherein the control unit (7) is designed to actuate at least the expiratory pressure level in such a way on the basis of the patient-close pressure measurement value by means of the inspiration valve (2) and the expiration valve (3), an RF oscillation with an RF ventilation frequency (17) as a variation in the amplitude in a range of 3 hertz to 20 hertz (3 sec -1 to 20 sec -1) with and with an RF oscillation ratio (20) of RF inspiration time duration RF-T i to RF expiration time duration RF-T e in a range of 1 to 1 to 1 to 3 (RF-I:E ratio of 1:1 to 1:3) is superimposed on the pressure level, wherein the control unit (7) is furthermore designed to carry out signal processing (1000) of the patient-close pressure measurement value, wherein the control unit (7) takes • at least one property of the pressure measuring line (94) from properties associated with a group of pressure measuring lines and • at least one ventilation setting (21) or a change in the at least one ventilation setting (21) from a group of ventilation parameters before and / or during operation of the ventilation device (1) into account in the performance of the signal processing (1000), wherein the group of properties associated with pressure measuring lines comprises at least one of the following elements: o length of the pressure measuring line (94), o diameter of the pressure measuring line (94), o material properties of the pressure measuring line (94), o flow resistance of the pressure measuring line (94), o conductivity type, characterizing the length, the diameter, the material properties and / or a flow resistance of the pressure measuring line (94), wherein the group of ventilation settings (21) that can be adjusted during operation of the ventilation device comprises at least one of the following elements: ◯ ventilation frequency (RR), ◯ ratio of inspiration time duration to expiration time duration (I:E ratio), ◯ inspiration time duration (T i), ◯ expiration time duration (T e), ◯ inspiration pressure level P insp, ◯ mean airway pressure P AW(19), ◯ RF pressure level P HF(18), ◯ expiratory pressure level P exp, ◯ positive end expiratory pressure (PEP), ◯ hf ventilation frequency (HF-RR) (17), ◯ adjusted HF oscillation ratio (HF-I:E ratio) (20), ◯ HF inspiration time duration (HF-T i), ◯ HF expiration time duration (HF-T e), ◯ inspiratory pressure plateau, ◯ inspiratory pressure increase gradient, ◯ mode of operation of a form of ventilation, ◯ patient type, characterized by age, sex, weight, gestational age, APGAR value, pathology of the patient (47).The ventilation device (1) according to claim 1, wherein the control unit (7) is configured to take account of the generation and / or propagation of pressure waves and reflections of pressure waves in the pressure measurement line (94) when performing the signal processing (1000, 4000) and to remove, reduce or compensate for interference signal components caused by generation and / or propagation of pressure waves and reflections of pressure waves in the pressure measurement line (94).The ventilation device (1) according to claim 1 or claim 2, wherein the control unit (7) is configured to apply digital signal filtering (400) when performing the signal processing (4000).The ventilation device (1) according to claim 1 or claim 2, wherein the control unit (7) is configured to include a physical model (100, 200) when performing the signal processing (1000), wherein the generation and / or propagation of pressure waves and reflections of pressure waves in the pressure measurement line (94) are taken into account in the physical model (100, 200).The ventilation device (1) according to claim 4, wherein the generation and propagation of pressure waves and reflections of pressure waves in the pressure measurement line (94) are taken into account in the physical model (100, 200), wherein the control unit (7) is configured to remove, reduce or compensate the interference signal components caused by generation and / or propagation of pressure waves and reflections of pressure waves in the pressure measurement line (94).The ventilation device (1) according to claim 5, wherein the physical model (100, 200) takes account of propagations of pressure waves and reflections of pressure waves in the pressure measurement line (94), which act through the provision of the inspiratory and expiratory pressure levels in the connection system (48) and / or at the connection element (46) into the pressure measurement line (94) and on the further pressure sensor (15) and bring about changes in the near-patient pressure measurement value and in the temporal course of the near-patient pressure measurement value, wherein the control unit (7) is designed to remove, reduce or compensate for the interference signal components generated through the provision of the inspiratory and expiratory pressure levels in the connection system (48) and / or at the connection element (46) and propagating pressure waves and reflections of pressure waves in the pressure measurement line (94).The breathing apparatus (1) according to claim 4 or claim 5, wherein a temperature and / or a composition of the inspiratory breathing gas mixture is taken into account in the physical model (100, 200).The ventilator (1) according to claim 4 or claim 5, wherein the physical model (100, 200) takes into account the properties associated with the pressure measurement line (94).The ventilation device (1) according to claim 3, wherein properties associated with the pressure measurement line (94) are taken into account by the control unit (7) when using the digital signal filtering (400).The ventilation device (1) according to claim 3, wherein properties associated with the connection system (48) and / or the connection element (46) are taken into account by the control unit (7) when using the digital signal filtering (400).The ventilation device (1) according to claim 4 or claim 5, wherein a suction nozzle (4) is arranged in the ventilation device (1) and wherein an operating state associated with the suction nozzle (4) or at least one property of the suction nozzle (4) is taken into account in the physical model (100, 200).The ventilation device (1) according to claim 3, wherein a suction nozzle (4) is arranged in the ventilation device (1), wherein an operating state associated with the suction nozzle (4) or at least one property of the suction nozzle (4) is taken into account by the control unit (7) when using the digital signal filtering (400).The ventilation device (1) according to claim 4 or claim 5, wherein a flow sensor (4) close to the patient is arranged in the ventilation device (1) or on or in the connecting element (46), and wherein at least one of the properties associated with the flow sensor (4) close to the patient, such as flow resistance, volume, diameter, structural size, structural length or sensor type, is taken into account in the physical model (100, 200).The ventilation device (1) according to claim 3, wherein a flow sensor (4) close to the patient is arranged in the ventilation device (1) or on or in the connecting element (46), and wherein at least one of the properties associated with the flow sensor (4) close to the patient, such as flow resistance, volume, diameter, size, structural shape, structural length or sensor type, is taken into account by the control unit (7) when using the digital signal filtering (400).The ventilation device (1) according to claim 4 or claim 5, wherein an arrangement for providing and carrying out a flushing of the pressure measurement line (94) is arranged in the ventilation device (1) and wherein an operating state associated with the arrangement for providing and carrying out a flushing of the pressure measurement line and / or at least one property of the arrangement are taken into account in the physical model (100, 200).The ventilation device (1) according to claim 3, wherein an arrangement for providing and carrying out a flushing of the pressure measurement line (94) is arranged in the ventilation device (1), wherein an operating state associated with the arrangement for providing and carrying out a flushing of the pressure measurement line and / or at least one property of the arrangement is taken into account by the control unit (7) when using the digital signal filtering (400).The ventilator (1) according to claim 4 or claim 5, wherein the physical model (100, 200) as a model of a pneumatic transmission line with line start (941) and line end (942) as a cooperation according to the formulae: P backward = R closed * P forward P meas = P forward + (R closed * P forward) Gain = 1 / G damping = G - 1 damping G forward = (1 / f perturbation ) - G delay P Prox = (P forward * G forward * G gain ) - (P backward * G damping * G delay * R open ), with the parameters: Pbackward(121), P forward(111), P meas(120), P' meas(220), P Prox(110, 210), R closed(350), R open(300), G gain(700), G damping(500), G delay(600), Gforecast(800), fdisturb(900), and wherein the control unit (7) is configured using these parameters (111, 121, 120, 220, 300, 350, 500, 600, 800, 900) and the formulae to determine a corrected patient-near pressure measurement value P Prox(110, 210, 2100) and to take into account the determined patient-near pressure measurement value P Prox(110, 210, 2100) during the control of the inspiration valve ( 2) and the expiration valve ( 3).

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