SYSTEM FOR VENTILATION OF LIVING BEINGS

Description

[0001] The invention relates to a system for ventilating living beings.

[0002] EIT (electrical impedance tomography) allows spatially differentiated information about the condition of a lung to be obtained. EIT is a non-invasive procedure in which weak alternating currents flow through the body, generating electrical voltages on the surface. EIT measures the surface tensions or conductivities on the body, which depend on the impedances or their distribution within, for example, the thorax. Pixels are recorded, with each pixel representing an electrical conductivity or impedance. The measured impedance is largely determined by the intrapulmonary air content, thus allowing conclusions to be drawn about the condition of the alveoli in specific areas of the lung. Due to its high temporal resolution, this procedure offers the possibility of detecting rapid physiological changes.The evaluation of EIT measurement signals and their conversion into images is the subject of various scientific publications (see Lionheart, WRB in Physiological Measurement 2004, 25, 1 and Schullcke, B. in Scientific Reports, 2016, 6, pages 25951ff). Further general details can also be found, for example, in DE 10 2013 203177 A1. DE 10 2017 007 224 A1 discloses a device and method for electrical impedance tomography with the determination of differential parameters based on EIT data.

[0003] Furthermore, it is known in the art to use EIT measurements to find appropriate positive end-expiratory pressure (PEEP) settings. For example, Costa et al. (Costa, EL in Intensive Care Med 2009; 35, pages 1132-1137) demonstrated how appropriate PEEP settings can be found by gradually changing PEEP and simultaneously measuring EIT. Because this method is time-consuming, it is only suitable for use at the beginning of ventilation. The patient's needs can change over the course of ventilation, and, particularly in the medical field, there is often insufficient time to apply this method more frequently.

[0004] The object of the present invention is therefore to provide a system for analyzing effective and safe ventilation of a living being. This object is achieved by the inventive system according to claim 1.

[0005] The system for ventilating a living being, comprising at least one ventilator and at least one EIT measuring device, wherein the ventilator comprises at least one controllable respiratory gas source and a programmable control unit for controlling the respiratory gas source and wherein the EIT measuring device comprises at least one sensor device for measuring impedance values ​​of at least one lung of the living being and at least one calculation and evaluation unit, wherein the system assigns the impedance values ​​measured via the at least one sensor device to pixels n, wherein the control unit is configured to a. to specify ventilation settings for the respiratory gas source in a reference phase R, wherein impedance values ​​are recorded at least at one point in time during the reference phase and a first key figure CR,n is calculated from the recorded impedance values ​​for each pixel n, and b. to specify ventilation settings for the respiratory gas source in at least one test phase T1 following the reference phase R, wherein the ventilation settings differ from the ventilation settings of the reference phase in at least one ventilation setting, and wherein impedance values ​​are recorded at at least at one point in time during the test phase T1 and a second key figure C T1,n is calculated from the recorded impedance values ​​for each pixel n.

[0006] In some embodiments of the system, the at least one test phase T1 is followed by at least one further test phase Tm, wherein the ventilation setting of each further test phase Tm differs from the first test phase T1 and the reference phase R in at least one ventilation setting, and wherein the system records impedance values ​​at at least one time point of each further test phase Tm and calculates a second characteristic number C Tm,n for each pixel n from the recorded impedance values.

[0007] In some embodiments, the system only follows the reference phase R with a test phase.

[0008] According to the invention, both the reference phase and each test phase comprise at least two breaths, wherein the reference phase and each test phase can be divided into at least two sub-phases, wherein at least one sub-phase represents a habituation phase and at least one sub-phase represents a measurement phase.

[0009] In some embodiments of the system, a positive end-expiratory pressure (PEEP) is applied to each breath during the expiratory phase, and during the inspiration phase, an inspiratory pressure P insp higher by the value ΔP or a tidal volume VT higher by a predetermined factor is applied.

[0010] In some embodiments of the system, an end-expiratory hold maneuver is performed at the end of at least one expiratory phase, wherein the end-expiratory hold maneuver comprises holding the PEEP and, if necessary, determining the intrinsic PEEP (PEEPi).

[0011] In some embodiments of the system, an end-inspiratory hold maneuver is performed at the end of at least one inspiration phase, wherein the end-inspiratory hold maneuver comprises holding the inspiratory pressure P insp and, if necessary, determining the plateau pressure and / or a surrogate for static compliance.

[0012] In some embodiments of the system, the end-expiratory hold maneuver and the end-inspiratory hold maneuver are performed during the measurement phase.

[0013] In some embodiments of the system, the measurement phase comprises at least two breaths, wherein the end-expiratory hold maneuver is performed during the expiratory phase of the penultimate breath and wherein the end-inspiratory hold maneuver is performed during the inspiratory phase of the last breath.

[0014] In some embodiments of the system, impedance values ​​are recorded at at least two times during both the reference phase R and the test phase T1, and the impedance values ​​are assigned to pixels n, wherein the first time point is during the end-expiratory hold maneuver and the recorded impedance values ​​are assigned to pixels n as I Min,n, and wherein the second time point is during the end-inspiratory hold maneuver and the recorded impedance values ​​are assigned to pixels n as I Max,n.

[0015] In some embodiments of the system, the following values ​​are calculated for the reference phase and test phase from the respective values ​​I Min,n and I Max,n: a. ΔI n for each pixel n as the difference between I Max,n and I Min,n , b. I min,Sum as the sum of all I Min,n , c. I Max,Sum as the sum of all I Max,n , d. ΔI global as the difference between I Max,Sum and I Min,Sum , where the calculation is only carried out for the respective pixel and the pixel is only included in the sums I Max,Sum and I Min,Sum is included if the pixel has ΔI n > 0.

[0016] In some embodiments of the system, the respective key figures CR,n and C T1,n of the reference and test phases are each calculated from the ratio of ΔI n to ΔI global, where a. the ratio ΔI n to ΔI global of the reference phase is multiplied by a factor CR,Stat to calculate CR,n and b. the ratio ΔI n to ΔI global of the test phase is multiplied by a factor C T1,Stat to calculate C T1,n, and where C R,Stat and C T1,Stat from the pressure difference between the end-expiratory hold maneuver and the end-inspiratory hold maneuver as well as the expiratory volume of the breath preceding the breath during which the end-expiratory hold maneuver is performed.

[0017] In some embodiments of the system, the index C T1,n of each pixel n is compared with the index CR,n of the same pixel n and the pixel n is assigned to one of at least two groups of numbers.

[0018] In some embodiments of the system, a. the pixels n for which C T1,n is greater than CR,n are assigned to a first group of numbers WIN and b. the pixels n for which C T1,n is less than CR,n are assigned to a second group of numbers LOSS.

[0019] In some embodiments of the system, a key number is calculated for each pixel n of the respective number group from the key numbers CT1,n and CR,n, where a. a key figure C WIN,n is calculated for the pixels n from the number group WIN and b. a key figure C LOSS,n is calculated for the pixels n from the number group LOSS.

[0020] In some embodiments of the system, a global key figure is calculated for each group of numbers WIN and LOSS with the sum of the respective key figures C WIN,n and C LOSS,n, respectively, where a. for the number group WIN with the sum of the key figures C WIN,n a key figure C WIN,global is calculated and b. for the number group LOSS with the sum of the key figures C LOSS,n a key figure C LOSS,global is calculated.

[0021] In some embodiments of the system, the key figures C WIN,global and C LOSS,global are interpreted and the size of the key figures is output alphanumerically and / or graphically.

[0022] In some embodiments of the system, the ventilation setting is taken into account when interpreting the key figures, in which the reference phase and the test phase T1 differ.

[0023] In some embodiments of the system, a message is generated based on the interpretation of the key figures C WIN,global and C LOSS,global, wherein the message contains at least one recommendation regarding the ventilation settings and wherein the message is output alphanumerically and / or graphically.

[0024] In some embodiments of the system, at least one of ΔP and / or PEEP and / or a tidal volume can be set as the ventilation setting that differs between the reference phase and the test phase.

[0025] In some embodiments of the system, at a PEEP setting which is increased in the test phase T1 compared to the reference phase, and a. if C WIN,global and C LOSS,global are below the set threshold, the recommendation is given not to change the ventilation settings, b. if C WIN,global is above the set threshold and C LOSS,global is below the set threshold, the recommendation is given to increase the PEEP, c. if C WIN,global is below the set threshold and C LOSS,global is above the set threshold, the recommendation is given not to change the PEEP and to consider a reduction in the inspiratory pressure P insp and / or the expiratory tidal volume VT, whereby a test phase with reduced inspiratory pressure P insp should first be set, d.If C WIN,global and C LOSS,global are above the set threshold, the recommendation is issued to increase PEEP and to consider a reduction of the inspiratory pressure P insp and / or expiratory tidal volume VT, whereby a test phase with reduced inspiratory pressure P insp should first be set.

[0026] In some embodiments of the system, at a PEEP setting which is reduced in the test phase T1 compared to the reference phase a. if C WIN,global and C LOSS,global are below the set threshold, the recommendation is given not to change the ventilation settings, b. if C WIN,global is above the set threshold and C LOSS,global is below the set threshold, the recommendation is given to reduce PEEP, c. if C WIN,global is below the set threshold and C LOSS,global is above the set threshold, the recommendation is given not to change the PEEP setting and to consider a recruitment maneuver, d. if C WIN,global and C LOSS,global are above the set threshold, the recommendation is given not to change the PEEP setting and to consider a recruitment maneuver and, where possible, to reduce P insp and / or VT.

[0027] In some embodiments of the system, at a P insp and / or VT setting which is increased in the test phase T1 compared to the reference phase and a. if C WIN,global and C LOSS,global are below the set threshold, the recommendation is given not to change the ventilation settings b. if C WIN,global is above the set threshold and C LOSS,global is below the set threshold, the recommendation is given to increase PEEP c. if C WIN,global is below the set threshold and C LOSS,global is above the set threshold, the recommendation is given to reduce the PEEP and / or P insp and / or VT settings d. if C WIN,global and C LOSS,global are above the set threshold, the recommendation is given to increase PEEP and, where possible, to reduce P insp and / or tidal volume.

[0028] In some embodiments of the system, with a P insp and / or VT setting which is reduced in the test phase T1 compared to the reference phase and a. if C WIN,global and C LOSS,global are below the set threshold, the recommendation is given not to change the ventilation settings, b. if C WIN,global is above the set threshold and C LOSS,global is below the set threshold, the recommendation is given to reduce PEEP and / or P insp and / or VT, c. if C WIN,global is below the set threshold and C LOSS,global is above the set threshold, the recommendation is given to increase PEEP, d. if C WIN,global and C LOSS,global are above the set threshold, the recommendation is given to increase PEEP and, if possible, to reduce P insp and / or the tidal volume.

[0029] In some embodiments of the system, a finding is created based on the interpretation of the key figures C WIN,global and C LOSS,global.

[0030] In some embodiments of the system, the message contains at least one finding in addition to the recommendation.

[0031] In some embodiments of the system, at a PEEP setting which is increased in the test phase (T1) compared to the reference phase (R), and a. if C WIN,global and C LOSS,global are below the set threshold, a finding is made that no significant changes were detected, b. if C WIN,global is above the set threshold and C LOSS,global is below the set threshold, a finding is made that recruitment occurs when PEEP is increased, c. if C WIN,global is below the set threshold and C LOSS,global is above the set threshold, a finding is made that increasing PEEP leads to overdistension, d. if C WIN,global and C LOSS,global are above the set threshold, a finding is made that increasing PEEP leads to both recruitment and overdistension.

[0032] In some embodiments of the system, at a PEEP setting which is reduced in the test phase (T1) compared to the reference phase (R) a. if C WIN,global and C LOSS,global are below the set threshold, a finding is made that no significant changes were observed, b. if C WIN,global is above the set threshold and C LOSS,global is below the set threshold, a finding is made that decreasing overextension can be observed, c. if C WIN,global is below the set threshold and C LOSS,global is above the set threshold, a finding is made that derecruitment can be observed, d. if C WIN,global and C LOSS,global are above the set threshold, a finding is made that both decreasing overextension and derectuation can be observed.

[0033] In some embodiments of the system, at a P insp and / or VT setting which is increased in the test phase (T1) compared to the reference phase (R) and a. if C WIN,global and C LOSS,global are below the set threshold, a finding is made that no significant changes can be observed, b. if C WIN,global is above the set threshold and C LOSS,global is below the set threshold, a finding is made that suspected tidal recruitment can be observed, c. if C WIN,global is below the set threshold and C LOSS,global is above the set threshold, a finding is made that overdistension can be observed, d. if C WIN,global and C LOSS,global are above the set threshold, a finding is made that overdistension can be observed.

[0034] In some embodiments of the system, at a P insp and / or VT setting which is reduced in the test phase (T1) compared to the reference phase (R) and a. if C WIN,global and C LOSS,global are below the set threshold, a finding is created that no significant changes can be observed, b. if C WIN,global is above the set threshold and C LOSS,global is below the set threshold, a finding is created that decreasing overdistension can be observed, c. if C WIN,global is below the set threshold and C LOSS,global is above the set threshold, a finding is created that tidal recruitment is suspected, d. if C WIN,global and C LOSS,global are above the set threshold, a finding is created that decreasing overdistension and tidal recruitment are suspected.

[0035] In some embodiments of the system, issued recommendations are automatically implemented and appropriate ventilation settings are made.

[0036] The object is further achieved by a system for ventilating a living being, comprising at least one ventilator and at least one EIT measuring device, wherein the ventilator comprises at least one controllable respiratory gas source and a programmable control unit for controlling the respiratory gas source and wherein the EIT measuring device comprises at least one sensor device for measuring impedance values ​​of at least one lung of the living being and at least one calculation and evaluation unit, wherein the system assigns the impedance values ​​measured via the at least one sensor device to pixels n, wherein the system is configured to carry out the following method steps a. Acclimatizing the subject to ventilation settings of a reference phase R b. Measuring impedances of the subject's lungs during the reference phase R c. Acclimatizing the subject to ventilation settings of a test phase T1 d. Measuring impedances of the subject's lungs during the test phase T1 e. Calculating key figures CR,n and C T1,n from the impedance values ​​from the measuring step f. Comparing the key figures CR,n and C T1,n g. Classifying the key figures CR,n and C T1,n into numerical groups WIN and LOSS h. Calculating key figures C WIN,global and C LOSS,global i. Comparing the key figures C WIN,global and C LOSS,global with threshold values ​​j. Evaluating, wherein the evaluating comprises at least the generation of a graphical representation of the key figures C WIN,global and C LOSS,global and wherein the step of evaluating (113) optionally comprises the creation of a finding taking into account the key figures C WIN,global and C LOSS,global k.Recommend, where recommending includes at least generating an alphanumeric output of recommendations regarding ventilation settings.

[0037] The object is further achieved by a method for ventilating a living being with a system for ventilating a living being, comprising at least one ventilator and at least one EIT measuring device, wherein the ventilator comprises at least one controllable respiratory gas source and a programmable control unit for controlling the respiratory gas source and wherein the EIT measuring device comprises at least one sensor device for measuring impedance values ​​of at least one lung of the living being and at least one calculation and evaluation unit, wherein the system assigns the impedance values ​​measured via the at least one sensor device to pixels n, wherein the control unit a. in a reference phase R, the respiratory gas source specifies ventilation settings, wherein impedance values ​​are recorded at at least one time point in the reference phase and a first key figure CR,n is calculated from the recorded impedance values ​​for each pixel n, and b. in at least one test phase T1 following the reference phase R, the respiratory gas source specifies ventilation settings, wherein the ventilation settings in at least one ventilation setting differ from the ventilation settings of the reference phase, and wherein impedance values ​​are recorded at at least one time point in the test phase T1 and a second key figure C T1,n is calculated from the recorded impedance values ​​for each pixel n.

[0038] It should be noted that the features listed individually in the claims can be combined with one another in any technically reasonable manner and demonstrate further embodiments of the invention. The description further characterizes and specifies the invention, particularly in conjunction with the figures.

[0039] It should also be noted that a conjunction "and / or" used herein between two features and linking them together is always to be interpreted in such a way that in a first embodiment of the subject matter according to the invention only the first feature can be present, in a second embodiment only the second feature can be present and in a third embodiment both the first and the second feature can be present.

[0040] A ventilator is any device that supports a user or patient in natural breathing, takes over the user's or patient's ventilation, and / or is used for respiratory therapy and / or otherwise influences the user's or patient's breathing. This includes, but is not limited to, CPAP and BiPAP devices, anesthesia or anesthesia machines, respiratory therapy devices, (clinical, outpatient, or emergency) ventilators, high-flow therapy devices, and coughing machines. Ventilators can also be understood as diagnostic devices for ventilation. Diagnostic devices can generally be used to record a patient's medical parameters. This also includes devices that can record and optionally process patient medical parameters in combination with or exclusively relating to breathing.

[0041] Unless expressly stated otherwise, a patient interface can be understood as any part or connected peripheral device of the ventilator that is intended for interaction with a patient, particularly for therapeutic or diagnostic purposes. In particular, a patient interface can be understood as a tracheostomy tube, a ventilator mask, or a mask connected to the ventilator. This mask can be a full-face mask, i.e. one that encloses the nose and mouth, or a nasal mask, i.e. one that only encloses the nose. Tracheal tubes and so-called nasal cannulas can also be used as masks. In some cases, the patient interface can also be a simple mouthpiece, for example a tube, through which the patient at least exhales.

[0042] The inventive measuring device is particularly suitable not only for use in the field of therapy and ventilation of patients, but can also be used in other areas where support for natural breathing may be desired, such as for divers, mountain climbers, in the protective equipment of firefighters, etc. The inventive measuring device can also be used in the field of determining various physiological parameters of a living being—not only for diagnostic purposes.

[0043] The system according to the invention is described below using the Figures 1 to 5 described in more detail by way of example.

[0044] The steps, calculations, and recommendations described below can expressly be carried out, at least in part, by evaluation, calculation, and / or control units of the ventilator 2. In particular, the calculations, evaluations, interpretations, outputs, and / or recommendations assigned, for example, to the EIT measuring device 3 can be carried out in an identical and / or slightly modified manner by the ventilator 2 and / or generally by the system 1. For example, the system 1 comprises at least one higher-level control unit and, if appropriate, corresponding calculation and evaluation units. Overall, the system (1) is preferably designed so that all steps, calculations, recommendations, evaluations (including the creation of findings), interpretations, and / or outputs can be carried out automatically.As a rule, it should only be necessary to manually adjust the ventilation settings for the reference phases and test phases.

[0045] Figure 1schematically shows an exemplary embodiment of the system 1 consisting of a ventilator 2 and an EIT measuring device 3. The system 1 is connected, for example, to a living being 4, wherein on the one hand the ventilator 1 is connected to the living being, for example via one or more tubes and a patient interface (both not shown), in order to convey respiratory gas to and, if necessary, away from the living being 4. The ventilator comprises at least one controllable respiratory gas source 21, a programmable control unit 22, a sensor unit 23, a storage unit 24, a processing unit 25, a monitoring unit 26 and a detection unit 27. As a rule, the ventilator 2 also comprises at least one user interface (not shown), via which at least inputs can be made on the ventilator 2.The ventilator 2 can also comprise a display device or be connected via an interface to a display unit via which data, values, information, messages, etc. can be displayed or output.

[0046] The controllable breathing gas source 21 is designed, for example, to deliver breathing gas to the living being 4. A breathing gas source 21 can, for example, be a blower and / or valve unit that generates the breathing gas from the ambient air and / or from gas cylinders.

[0047] The control unit 22 serves, for example, to control the ventilator 2, in particular the respiratory gas source 21. For this purpose, the control unit 22 is designed, among other things, to control the ventilation pressure and / or flow generated by the respiratory gas source 21. The control unit 22 can also be designed to control other components and / or units of the ventilator 2. In some embodiments, the control unit 22 can also be further subdivided and consist of several control units, each of which controls an individual unit and / or component of the ventilator 2. In particular, the control unit 22 is configured to control the ventilator 2 at least partially automatically. In particular, the control unit 22 is programmable to perform various maneuvers during which at least one ventilation setting is changed.

[0048] The sensor unit 23 is configured to record measured values, in particular parameters related to respiratory flow, respiratory volume, respiratory rate, inhalation and exhalation duration, respiratory contour, leakage, or therapy pressure. Optionally, the sensor unit 23 can perform additional measurements of components or temperature of the respiratory gas or blood. The sensor unit 23 transmits the recorded measured values ​​to the processing unit 24.

[0049] The processing unit 25 is designed, for example, as a combined processing and calculation unit and can process the acquired measured values. For example, the processing unit 25 can perform smoothing, artifact removal, or downsampling of the measured values. Furthermore, the processing unit 25 is designed to calculate signals and / or parameters, such as a mean, a median, a percentile, a derivative, a frequency distribution, a duration, or a proportion of exceeding or falling below threshold values, from the processed measured values ​​acquired by the sensor unit 23.

[0050] The detection unit 26 is configured to detect events / conditions such as alarms, apnea, artifacts, coughs, oxygen saturations, asynchronies between device and user and / or spontaneous breaths.

[0051] The storage unit 24 stores, among other things, the values / parameters detected by the sensor unit 23 and / or the values, data, and / or information processed by the processing unit 25, or at least temporarily stores them. The information, data, and values ​​obtained by the recognition unit 26 can also be and / or are at least temporarily stored in the storage unit. Temporary storage means, for example, that the values, data, and / or information are stored until a transmission and are then deleted, for example, or released for overwriting.

[0052] The monitoring unit 27 detects, for example, technical problems with the ventilator 2. Technical problems can include, for example, a low battery level, electronic errors, a defective battery, a defective component, a power failure, a malfunctioning accessory, an implausible measured value, or a temperature outside of a permissible range. If a technical problem is detected, the monitoring unit 27 can display or transmit an alarm on the ventilator 2 via an interface.

[0053] The EIT measuring device 3 is connected to the ventilator 2, for example, via an interface (not shown). In some embodiments, the EIT measuring device 3 can also be at least partially integrated into the ventilator 2. The EIT measuring device 3 has at least one sensor device 31 and a calculation and evaluation unit 32.

[0054] The sensor device 31 comprises a plurality of surface electrodes arranged on the skin of the living being 4. Typically, the sensor device comprises at least four surface electrodes, although between 15 and 65 surface electrodes are frequently used. However, a number of more than 64 surface electrodes is also conceivable. An alternating current with a low amplitude and a low current intensity (usually in the range of single-digit milliampere values) flows through two of the surface electrodes, for example, two adjacent surface electrodes. This alternating current is measured by the other surface electrodes, for example, in the form of impedance values.For example, the EIT measuring device 3 is configured such that the surface electrodes between which the alternating current flows switch after the measurement, for example, to the two adjacent surface electrodes. This process is repeated, for example, until the alternating current flows again between the first two surface electrodes. For example, this completes a measurement cycle. In some embodiments of the EIT measuring device 3, the current always flows between the same two surface electrodes and is always measured by the same other surface electrodes.

[0055] The EIT measuring device 3 is further configured such that, for example, via the calculation and evaluation unit 32, the impedance values ​​measured by the sensor device 31 can be assigned to individual pixels. Furthermore, the calculation and evaluation unit 32 is configured to calculate various key figures from the impedance values ​​and, based on the key figures, to perform an evaluation and, for example, to generate recommendations regarding ventilation settings, such as the inspiratory pressure P insp and / or the positive end-expiratory pressure PEEP and / or the expiratory tidal volume VT.

[0056] The system 1 is configured, for example, such that the EIT measuring device 3 and / or the ventilator 2 measures impedance values ​​at at least two points in time during a ventilation maneuver performed by the ventilator 2, evaluates these impedance values ​​or calculates key figures using the impedance values ​​and then, taking into account the settings of the ventilation maneuver, creates recommendations for the ventilation settings and, if necessary, outputs them, for example via the display device of the ventilator 2 or an interface via which, for example, a telemonitoring system is connected.

[0057] Based on the Figures 2 to 4 The ventilation maneuver and the evaluation of the impedance measurements will be explained using examples.

[0058] In Figure 2shows an example sequence of the ventilation maneuver, which can be set on the ventilator 2. The x-axis represents the pressure value P and the y-axis the time t. Essentially, the ventilation maneuver consists of two phases, the reference phase R and a test phase T1. The test phase T1 differs from the reference phase R at least in that one ventilation setting is different. In some embodiments, further test phases Tm can also be set, with each further test phase also differing from all other reference phases R and test phases T1, Tm in at least one ventilation setting. Here, "m" denotes the respective number of the test phase, the second test phase would correspondingly be designated T2, and so on. For example, the reference phase R and the test phase T1 differ in the positive end-expiratory pressure (PEEP) and / or the inspiratory pressure P insp .For example, on ventilator 2, you can set which ventilation setting and to what extent the ventilation setting differs between reference phase R and test phase T1. For the example shown in . Figure 2For example, in the maneuver shown as an example, a reduced PEEP is provided for the test phase T1 (marked with PEEP2), whereby the pressure difference ΔP between the PEEP and the inspiratory pressure P insp remains the same, which simultaneously results in the inspiratory pressure P insp in the test phase T1 (marked with P insp 2) being reduced by the same amount as the PEEP. In addition to a reduction in PEEP, an increase in PEEP can also be set. A reduction / increase in the pressure difference ΔP (difference between P insp and PEEP) or a reduction / increase by means of a factor of the set tidal volume can also be set for the ventilation maneuver, whereby, for example, the PEEP is kept constant. In some embodiments, an increase / reduction in PEEP can also be set, whereby the inspiratory pressure P insp remains constant, i.e. ΔP is increased / reduced accordingly. During the reference phase R, according to the maneuver in Figure 2 Subject 4 is ventilated or assisted in breathing with a positive end-expiratory pressure PEEP1 and an inspiratory pressure P insp 1. During test phase T1, the PEEP changes while the pressure difference ΔP remains constant compared to the reference phase. Subject 4 is ventilated or assisted in breathing with a positive end-expiratory pressure PEEP2 and an inspiratory pressure P insp 2.

[0059] Each phase of the ventilation maneuver comprises several breaths, consisting of inspiration and expiration. For example, a number of breaths from 5 to 120, preferably 5 to 60, can be set for the reference phase R and each of the test phases T1, Tm. The reference phase R and the test phase T1 also comprise at least two subphases – a habituation phase G1, G2 and a measurement phase M1, M2. The habituation phase G1, G2 serves to allow the living being 4 to become accustomed to the ventilation settings. The measurement phases M1, M2 follow the respective habituation phase G1, G2 and usually comprise two breaths, although the measurement phase M1, M2 can also comprise more breaths. Depending on the definition – i.e., what is considered the beginning of a breath – the measurement phase can also comprise only one breath.During the measurement phase M1, M2, impedance values ​​are recorded by the EIT measuring device 3 at at least two points in time, whereby a point in time can also be equated with the time period required for one measurement cycle of the EIT measuring device 3.

[0060] According to the Figure 2 In the exemplary ventilation maneuver sequence shown, an end-expiratory hold maneuver EH1, EH2 is performed at the end of expiration of the penultimate breath of the respective reference phase R or test phase T1. During the end-expiratory hold maneuver EH1, EH2, the PEEP pressure level is maintained at the end of expiration. The first time at which the EIT measuring device 3 records or measures the impedance values ​​occurs during this hold maneuver EH1, EH2.

[0061] After the penultimate breath, at the end of the inspiration of the last breath of the respective measurement phase M1, M2, an inspiratory hold maneuver IH1, IH2 follows, during which the pressure level of the inspiratory pressure P insp 1, P insp 2 is maintained. Analogous to the expiratory hold maneuvers EH1, EH2, there is a time at which the EIT measuring device 3 measures or records impedance values ​​during the inspiratory hold maneuvers IH1, IH2.

[0062] The length of the hold maneuvers EH1, EH2, IH1, and IH2 can be adjusted, for example, via the ventilator 2 and / or the EIT measuring device 3. The lengths can be set, for example, in a range from 0.2 seconds to 8 seconds, with the respective inspiratory hold maneuvers IH1 and IH2 being of equal length, and the respective expiratory hold maneuvers EH1 and EH2 being of equal length. However, the inspiratory hold maneuvers do not have to be the same length as the expiratory hold maneuvers.

[0063] The change in PEEP, P insp, and / or ΔP of the test phase T1 compared to the reference phase R can also be entered, for example, via the ventilator 2 and / or the EIT measuring device 3. For example, an absolute change in mbar can be entered and / or a relative change can be set as a factor.

[0064] In some embodiments of the system 1, it is also possible to make the settings via a device connected to the system 1 via an interface, for example a telemonitoring unit.

[0065] The measured impedance values ​​are assigned, for example by the calculation and evaluation unit 32, to individual pixels n, where n represents a designation, for example a consecutive numbering of the pixels. For a total of 1024 pixels, this results in a count for n from 1 to 1024. The calculation and evaluation unit 32 is further designed to consistently assign the impedance values ​​to the pixel depending on the phase (reference and test phase) and the measurement time (EH1, IH1, EH2, IH2). Accordingly, for example, after completion of the ventilation maneuver from Figure 2 Each pixel is assigned at least four impedance values ​​I (one each from EH1, IH1, EH2, IH2).

[0066] The calculation and evaluation unit 32 is further configured to calculate, from the impedance values ​​of the respective reference or test phase, a characteristic CR,n for the reference phase R and a characteristic C T1,n for the test phase T1 for each pixel. For this purpose, the calculation and evaluation unit 32 first calculates the difference ΔI n between I Max,n and I Min,n for each phase R, T1, where I Max,n represents the respective impedance value of the pixel during the measurement during the expiratory hold maneuver EH1 or EH2, and I Min,n represents the respective impedance value of the pixel during the measurement during the inspiratory hold maneuver IH1 or IH2: Δ I n = I Max , n − I Min , n

[0067] In some embodiments, individual pixels are only included in the calculation and evaluation if ΔI n is greater than zero. Furthermore, the difference ΔI global between I Max,global and I Min,global is calculated, where I Max,global represents the sum of the impedance values ​​of all pixels during the measurement during the expiratory hold maneuver EH1 or EH2, and I Min,global represents the sum of the impedance values ​​of all pixels during the measurement during the inspiratory hold maneuver IH1 or IH2: Δ I global = I Max , global − I Min , global = ∑ I Max , n − ∑ I Min , n

[0068] If the value ΔI n for a pixel is equal to or below zero, this pixel is not included in the calculation of ΔI global. Each pixel n therefore receives two values ​​ΔI n - one for the reference phase R and one for the test phase T1. Likewise, a value ΔI global is calculated for the reference phase R as well as for the test phase T1. The calculation and evaluation unit 32 then calculates the key figures CR,n and C T1,n for the respective phase R or T1 according to C R , n = Δ I n Δ I global ⋅ C R , Stat C T 1 , n = Δ I n Δ I global ⋅ C T 1 , Stat where the factors CR,Stat and C T1,Stat are calculated from the tidal volume VT and / or an expiratory volume determined, for example, by the EIT measuring device 3 or the ventilator 2, as well as the pressure difference between the inspiratory hold maneuver IH1 or IH2 and the expiratory hold maneuver EH1 or EH2, and represent statistical compliance values. Related to Figure 2The difference between P insp 1 and PEEP1 is used for CR,Stat and the difference between P insp 2 and PEEP2 is used for CT1,Stat.

[0069] After calculation, the key figures CR,n and C T1,n of the individual pixels are compared and assigned to one of two groups of numbers. The two groups of numbers are labeled, for example, WIN and LOSS. The pixels for which C T1,n is greater than CR,n are assigned to the WIN group by the calculation and evaluation unit 32, while the pixels for which C T1,n is less than CR,n are assigned to the LOSS group. A value for C T1,n greater than CR,n can, for example, be viewed as a compliance gain of the individual pixel in the test phase T1 compared to the reference phase R.

[0070] For a further step, the calculation and evaluation unit 32 is designed to calculate a key figure C WIN,global using the key figures CR,n and C T1,n of the pixels of the number group WIN and to calculate a key figure C LOSS,global using the key figures CR,n and C T1,n of the pixels of the number group LOSS.

[0071] The key figures C WIN,global and C LOSS,global are calculated by multiplying the sum of all key figures for the compliance gain C WIN,n of the pixels from the WIN number group by 100 or by multiplying the sum of all key figures for the compliance loss C LOSS,n of the pixels from the LOSS number group by 100 and represent a global compliance gain (WIN) or compliance loss (LOSS) related to the living being: C WIN , global = ∑ C WIN , n ⋅ 100 C LOSS , global = ∑ C LOSS , n ⋅ 100

[0072] The key figures C WIN,global and C LOSS,global ultimately indicate global compliance gains or losses in percent, for example, based on the statistical compliance CR,Stat . The calculation and evaluation unit 32 calculates the compliance gain C WIN,n or the compliance loss C LOSS,n of each individual pixel based on C WIN , n = C T 1 , n − C R , n C R , Stat C LOSS , n = C T 1 , n − C R , n C R , Stat using CT1,n and CR,n of the pixels of the respective number group WIN and LOSS.

[0073] In particular, the key figures for the global compliance loss C LOSS,global and the global compliance gain C WIN,global can be used by the calculation and evaluation unit 32 to evaluate the ventilation and / or the ventilation settings of the ventilator 2. For example, the calculation and evaluation unit 32 checks whether the key figures C WIN,global and / or C LOSS,global exceed definable thresholds. The thresholds can, for example, be programmable in the system and have a range from 1% to 99%, for example, in a range from 10% to 50%. In some embodiments, the thresholds can also be set independently of one another. The evaluation by the calculation and evaluation unit 32 is based on whether and which of the key figures C WIN,global and C LOSS,global reach or exceed the respective threshold. Overall, this results in four possible outcomes: Both C WIN,global and C LOSS,global are below the threshold. C WIN,global is above the threshold and C LOSS,global is below the threshold. C WIN,global is below the threshold and C LOSS,global is above the threshold. C WIN,global and C LOSS,global are above the threshold.

[0074] System 1 is generally designed to output an alphanumeric and / or graphical analysis of the key figures. For example, the analysis or output of the key figures can be presented in the form of a bar chart, with the bar size corresponding to the size of the respective key figure, for example, in relation to the statistical compliance CR,Stat. A pie chart representation is also conceivable.

[0075] Using the global compliance losses and gains and the settings of the ventilation maneuver, System 1 can issue recommendations regarding the ventilation settings. To enable such a statement, the reference phase R of the ventilation maneuver should correspond to the ventilation settings of the previous ventilation. As already described, the test phase T1 differs from the reference phase R in at least one ventilation setting. System 1 is designed to generate and / or issue recommendations regarding the ventilation settings based specifically on this different ventilation setting.

[0076] The global compliance losses (C_LOSS,global) and compliance gains (C_WIN,global) can also be used to generate a report. Just like the recommendations, the reference phase R of the ventilation maneuver should correspond to the ventilation settings of the previous ventilation to enable the corresponding creation of a report. Alternatively, in some embodiments, the report is created first, and the recommendations are generated or issued based on this report.

[0077] The findings are displayed alphanumerically and / or graphically, for example together with the recommendation regarding ventilation settings.

[0078] Based on the described example setting options for the ventilation maneuver (increasing / decreasing PEEP, P insp, VT, ΔP while maintaining P insp) and the possible results of the evaluation of the C WIN,global and C LOSS,global indicators, the following recommendation options arise. The recommendations are output alphanumerically, for example.

[0079] If the PEEP of the test phase T1 is higher than the PEEP of the reference phase R, a. if C WIN,global and C LOSS,global are below the set threshold, the recommendation is given not to change the ventilation settings; furthermore, a finding can be made that no significant changes have been detected, b. if C WIN,global is above the set threshold and C LOSS,global is below the set threshold, the recommendation is given to increase PEEP; furthermore, a finding can be made that recruitment occurs when PEEP is increased, c.if C WIN,global is below the set threshold and C LOSS,global is above the set threshold, the recommendation is given not to change the PEEP and to consider a reduction of P insp and / or VT, whereby the ventilation maneuver should first be carried out including measurements with a reduced P insp in test phase T1, moreover a finding can be made that increasing the PEEP leads to over-expansion, i.e. if C WIN,global and C LOSS,global are above the set threshold, the recommendation is given to increase the PEEP and to consider a reduction of P insp and / or VT, whereby the ventilation maneuver should first be carried out including measurements with a reduced P insp in test phase T1, moreover a finding can be made that increasing the PEEP leads to both recruitment and over-expansion.

[0080] If the PEEP of the test phase T1 is reduced compared to the PEEP of the reference phase R, a. if C WIN,global and C LOSS,global are below the set threshold, the recommendation is given not to change the ventilation settings and / or to reduce the PEEP; furthermore, a finding can be made that no significant changes have been detected, b. if C WIN,global is above the set threshold and C LOSS,global is below the set threshold, the recommendation is given to reduce the PEEP; furthermore, a finding can be made that decreasing over-expansion can be observed, c. if C WIN,global is below the set threshold and C LOSS,global is above the set threshold, the recommendation is given not to change the PEEP setting and / or to increase it and to consider a recruitment maneuver; furthermore, a finding can be made that derecruitment can be observed, d.If C WIN,global and C LOSS,global are above the set threshold, the recommendation is to keep the PEEP setting and to consider a recruitment maneuver and, where possible, to reduce P insp and / or VT; moreover, a finding that both decreasing overdistension and derectuation can be observed can be made.

[0081] If the inspiratory pressure P insp in the test phase T1 is increased compared to P insp of the reference phase R, a. if C WIN,global and C LOSS,global are below the set threshold, the recommendation is given not to change the ventilation settings, furthermore a finding can be made that no significant changes can be observed, b. if C WIN,global is above the set threshold and C LOSS,global is below the set threshold, the recommendation is given to increase the PEEP, furthermore a finding can be made that tidal recruitment is suspected, c. if C WIN,global is below the set threshold and C LOSS,global is above the set threshold, the recommendation is given to reduce the PEEP and / or P insp and / or VT settings, furthermore a finding can be made that over-distension can be observed.If C WIN,global and C LOSS,global are above the set threshold, a recommendation is made to increase PEEP and / or, where possible, to reduce P insp and / or tidal volume; moreover, a finding that overdistension and suspected tidal recruitment are observed may be made.

[0082] If the inspiratory pressure P insp in the test phase T1 is reduced compared to P insp of the reference phase R, a. if C WIN,global and C LOSS,global are below the set threshold, the recommendation is given not to change the ventilation settings, furthermore a finding can be made that no significant changes can be observed, b. if C WIN,global is above the set threshold and C LOSS,global is below the set threshold, the recommendation is given to reduce PEEP and / or P insp and / or VT, furthermore a finding can be made that decreasing overdistension can be observed, c. if C WIN,global is below the set threshold and C LOSS,global is above the set threshold, the recommendation is given to increase PEEP, furthermore a finding can be made that tidal recruitment is suspected.If C WIN,global and C LOSS,global are above the set threshold, a recommendation is made to increase PEEP and / or, where possible, to reduce P insp and / or tidal volume; furthermore, a finding may be made that declining overdistension and a suspicion of tidal recruitment are observed.

[0083] In some embodiments, system 1 is configured to automatically implement the recommendations and adjust the ventilation settings according to the evaluation and recommendation. System 1 can also be configured, for example, to perform a recommended recruitment maneuver and / or additional ventilation maneuvers, including measurements.

[0084] For example, it is also conceivable that System 1 performs several ventilation maneuvers and measurements with the same settings and generates and issues a corresponding recommendation based on an average or mean of the results.

[0085] The Figures 3 and 4 show an exemplary embodiment of the alphanumeric and visual output of the evaluation and recommendations of the system 1. In the embodiment of the Figure 3As an example, a visual representation 14 of the selected maneuver setting (here an increased PEEP in test phase T1) can be seen next to the graphical output 15 of the evaluation of the key figures C WIN,global (12), C LOSS,global (13) and CR,Stat (11) and the alphanumeric output of the recommendations 16. In addition, a finding can also be displayed in the field of recommendations 16, which is created, for example, on the basis of the key figures C WIN,global (12) and C LOSS,global (13) and, for example, automatically by the system (1). In the case shown, the evaluation of the key figures is represented graphically as a bar chart. For example, the key figure C WIN,global is above the set threshold and the key figure C LOSS,global is below the set threshold.In the alphanumeric edition of Recommendations 16, it should be recommended to increase the PEEP of the ventilation settings in order to achieve more efficient and / or better ventilation.

[0086] Figure 4 shows, by way of example, another possible alphanumeric and graphical representation of the ventilation maneuver 14, the evaluation of the key figures 15, and the recommendations 16. For example, it is shown here that both C WIN,global (12) and C LOSS,global (13) are above the set threshold, with the ventilation maneuver setting specifying an increased inspiratory pressure P insp for test phase T1. Therefore, the system outputs, for example, an alphanumeric text in the field for recommendation 16 stating that PEEP should be increased and, where possible, P insp and / or the tidal volume should be reduced.

[0087] Figure 5shows an example and schematically a sequence of steps which are carried out by the system in order to determine the ventilation manoeuvre based on the impedance values ​​measured by the EIT measuring device and the ventilation manoeuvre (cf. Figure 2 ) to generate recommendations on ventilation settings.

[0088] The first step is setting 100 of the ventilation maneuver. Among other things, the ventilation setting is selected, in which the test phase T1 differs from the reference phase R, as well as the magnitude of the difference. During setting 100, the length of the inspiratory and expiratory hold maneuvers EH1, EH2, IH1, IH2, as well as the duration (e.g., in the form of the number of breaths) of the respective reference phase R and test phase T1 can also be selected. During setting 100, the respective threshold values ​​for the C WIN,global and C LOSS,global indicators can also be set.

[0089] The setting 100 is followed by the step of first habituation 101 of the living being to the ventilation settings of the reference phase R. Following the habituation 101, the measurement 102 in the reference phase R follows. In this process, impedance values ​​are recorded during the last breaths of the reference phase R.

[0090] The measurement step 102 is followed by the habituation step 103, which serves to habituate the subject 103 to the ventilation settings of test phase T1. During test phase T1, the change in the ventilation settings from the adjustment step 100 is applied. The habituation step 103 is followed by the measurement step 104 of the impedance values ​​during test phase T1.

[0091] The measuring steps 102, 104 are followed by the calculating steps 105, 106, respectively. Calculating 105 includes calculating the characteristic CR,n for each pixel from the impedance values ​​of the reference phase R1 measured during measuring 102. Calculating 106 includes calculating the characteristic CT1,n for each pixel from the impedance values ​​of the test phase T1 measured during measuring 104.

[0092] The following comparison 107 involves comparing the key figures CR,n and C T1,n . Based on the results of the comparison 107, the pixels and the associated key figures CR,n and C T1,n are classified 108 into the number groups WIN and LOSS, respectively.

[0093] After the classification 108, the system 1 performs the steps of calculating 109, 110, wherein the calculation 109 comprises the calculation of the key figure C WIN,global and the calculation 110 comprises the calculation of the key figure C LOSS,global.

[0094] The key figures C WIN,global and C LOSS,global are compared with the respective set threshold values ​​in the following comparison steps 111, 112, whereby during the comparison 111 the key figure C WIN,global is compared with the set threshold value for C WIN,global and during the comparison 112 the key figure C LOSS,global is compared with the set threshold value for C LOSS,global.

[0095] After the comparison 111, 112, the system 1 performs the evaluation step 113. During the evaluation 113, for example, a graphical representation of the key figures C WIN,global and C LOSS,global is generated, and an evaluation is carried out to determine whether or which of the key figures C WIN,global and C LOSS,global are above the set threshold values. The evaluation step 113 also includes, for example, the creation of a finding based on the key figures C WIN,global (12) and C LOSS,global (13).

[0096] Based on the evaluation from the evaluation step 113, the recommendation step 114 takes place, whereby the system 1 generates a recommendation for the ventilation settings according to the setting of the ventilation maneuver and the key figures C WIN,global and C LOSS,global or whether and which of the key figures C WIN,global and C LOSS,global exceed the set threshold values ​​and, if necessary, outputs it as an alphanumeric message.

[0097] Preferably, steps 101 to 114 are performed fully automatically by the system 1 as soon as the setting 100 is completed. In some embodiments, the recommendation 114 is followed, for example, by an implementation step in which the system automatically applies the generated recommendations to the ventilation settings. List of reference symbols

[0098] 1System 2Ventilator 3EIT measuring device 4Living being 11C R,Stat 12C WIN,global 13C LOSS,global 14Representation of ventilation maneuver 15Output evaluation 16Output recommendation 21Respiratory gas source 22Control unit 23Sensor unit 24Storage unit 25Processing unit 26Monitoring unit 27Detection unit 31Sensor device 32Calculation and evaluation unit 100Setting 101Acclimatization 102Measurement 103Acclimatization 104Measurement 105Calculating 106Calculating 107Comparing 108Classifying 109Calculating 110Calculating 111Comparing 112Comparing 113Evaluating 114Recommendating EH1Expiratory hold maneuver, reference phase EH2Expiratory Hold maneuver, test phase G1, habituation phase, reference phase G2, habituation phase, test phase IH1, inspiratory hold maneuver, reference phase IH2, inspiratory hold maneuver, test phase M1, measurement phase, reference phase M2, measurement phase, test phase P pressure PEEP1, PEEP, reference phase PEEP2, PEEP, test phase P insp 1, inspiratory pressure, reference phase P insp 2, inspiratory pressure,Test phase RReference phase T1Test phase tTime,

Claims

1. A system (1) for ventilating an organism (4), comprising at least one ventilator (2) and at least one EIT measuring apparatus (3), wherein the ventilator (2) comprises at least one controllable breathing gas source (21) and a programmable control unit (22) for controlling the breathing gas source (21) and wherein the EIT measuring apparatus (3) comprises at least one sensor device (31) for measuring impedance values of at least one lung of the organism as well as at least one calculation and evaluation unit (32), wherein the system (1) assigns the impedance values measured using the at least one sensor device (31) to pixels n, characterized in that the control unit (22) is configured a. to specify ventilation settings for the breathing gas source (21) in a reference phase (R), wherein impedance values are recorded at at least one point in time in the reference phase (R) and a first characteristic number CR,n is calculated for each pixel n from the recorded impedance values, and b. to specify ventilation settings for the breathing gas source (21) in at least one test phase (T1) that follows on from the reference phase (R), wherein the ventilation settings differ from the ventilation settings of the reference phase (R) in at least one ventilation setting and wherein impedance values are recorded at at least one point in time in the test phase (T1) and a second characteristic number CT1,n is calculated for each pixel n from the recorded impedance values, wherein both the reference phase (R) and each test phase (T1, Tm) comprises at least two breaths, wherein the reference phase (R) and each test phase (T1, Tm) can be divided into at least two subphases, wherein at least one subphase constitutes an acclimatization phase (G1, G2) and at least one subphase constitutes a measurement phase (M1, M2).

2. The system according to at least one of the preceding claims, characterized in that at least one further test phase (Tm) follows on from the at least one test phase (T1), wherein the ventilation setting of each further test phase (Tm) differs from the first test phase (T1) and the reference phase (R) in at least one ventilation setting and wherein the system (1) records impedance values at at least one point in time in each further test phase (Tm) and calculates a second characteristic number CTm,n for each pixel n from the recorded impedance values.

3. The system (1) according to at least one of the preceding claims, characterized in that a positive end-expiratory pressure (PEEP) is applied during each breath during the expiration phase and an inspiratory pressure Pinsp that is higher by the value ΔP or a tidal volume (VT) that is higher by a settable factor is applied during the inspiration phase.

4. The system (1) according to at least one of the preceding claims, characterized in that an end-expiratory hold maneuver (EH1, EH2) is performed at the end of at least one expiration phase, wherein the end-expiratory hold maneuver (EH1, EH2) comprises holding the PEEP, wherein an end-inspiratory hold maneuver (IH1, IH2) is performed at the end of at least one inspiration phase, wherein the end-inspiratory hold maneuver (IH1, IH2) comprises holding the inspiratory pressure Pinsp.

5. The system (1) according to at least one of the preceding claims, characterized in that the end-expiratory hold maneuver (EH1, EH2) and the end-inspiratory hold maneuver (IH1, IH2) are performed during the measurement phase (M1, M2), wherein the measurement phase (M1, M2) comprises at least two breaths and wherein the end-expiratory hold maneuver (EH1, EH2) is performed during the expiration phase of the penultimate breath and wherein the end-inspiratory hold maneuver (IH1, IH2) is performed during the inspiration phase of the last breath.

6. The system (1) according to at least one of the preceding claims, characterized in that impedance values are recorded and assigned to pixels n both during the reference phase (R) and during the test phase (T1) at at least two points in time, wherein the first point in time is during the end-expiratory hold maneuver (IH1, IH2) and the recorded impedance values are assigned to the pixels n as IMin,n and wherein the second point in time is during the end-inspiratory hold maneuver (EH1, EH2) and the recorded impedance values are assigned to the pixels n as IMax,n, wherein the following values are calculated from the respective values IMin,n and IMax,n in each case for the reference phase (R) and test phase (T1): a. ΔIn for each pixel n as the difference between IMax,n and IMin,n, b. IMin,Sum as the sum of all IMin,n, c. IMax,Sum as the sum of all IMax,n, d. ΔIglobal as the difference between IMax,Sum and IMin,Sum, wherein the calculation is only performed for the relevant pixel and the pixel is only included in the sums IMax,Sum and IMin,Sum if ΔIn > 0 applies for the pixel.

7. The system (1) according to at least one of the preceding claims, characterized in that the respective characteristic numbers CR,n and CT1,n of the reference phase and test phase, respectively, are calculated in each case from the ratio of ΔIn to ΔIglobal, wherein a. the ratio of ΔIn to ΔIglobal of the reference phase is multiplied by a factor CR,Stat in order to calculate CR,n, and b. the ratio of ΔIn to ΔIglobal of the test phase is multiplied by a factor CT1,Stat in order to calculate CT1,n, wherein CR,Stat and CT1,Stat are determined from the pressure difference between the end-expiratory hold maneuver and the end-inspiratory hold maneuver as well as from the expiration volume of the breath preceding the breath during which the end-expiratory hold maneuver is performed.

8. The system (1) according to at least one of the preceding claims, characterized in that the characteristic number CT1,n of each pixel n is compared with the characteristic number CR,n of the same pixel n and the pixel n is assigned to one of at least two groups of numbers, wherein a. the pixels n for which CT1,n is greater than CR,n are assigned to a first group of numbers WIN, and b. the pixels n for which CT1,n is less than CR,n are assigned to a second group of numbers LOSS.

9. The system (1) according to at least one of the preceding claims, characterized in that a characteristic number is calculated from the characteristic numbers CT1,n and CR,n for each pixel n of the relevant group of numbers, wherein a. a characteristic number CWIN,n is calculated for the pixels n from the group of numbers WIN, and b. a characteristic number CLOSS,n is calculated for the pixels n from the group of numbers LOSS, and c. a characteristic number CWIN,global is calculated for the group of numbers WIN using the sum of the characteristic numbers CWIN,n, and d. a characteristic number CLOSS,global is calculated for the group of numbers LOSS using the sum of the characteristic numbers CLOSS,n.

10. The system (1) according to at least one of the preceding claims, characterized in that the system (1) is configured to interpret the characteristic numbers CWIN,global and CLOSS,global and to alphanumerically and / or graphically output the magnitude of the characteristic numbers, wherein the ventilation setting in which the reference phase (R) and the test phase (T1) differ from one another is included in the interpretation of the characteristic numbers CWIN,global and CLOSS,global.

11. The system (1) according to at least one of the preceding claims, characterized in that a report is generated based on the interpretation of the characteristic numbers CWIN,global and CLOSS,global, wherein the report contains at least one recommendation with regard to the ventilation settings and wherein the report is output alphanumerically and / or graphically, wherein the ventilation setting for which the report contains at least one recommendation is at least one of ΔP and / or PEEP.

12. The system (1) according to at least one of the preceding claims, characterized in that, in the case of a PEEP setting that is increased in the test phase (T 1) relative to the reference phase (R) and a. if CWIN,global and CLOSS,global are below the set threshold value, the recommendation not to change the ventilation settings is output, b. if CWIN,global is above the set threshold value and CLOSS,global is below the set threshold value, the recommendation to increase the PEEP is output, c. if CWIN,global is below the set threshold value and CLOSS,global is above the set threshold value, the recommendation not to change the PEEP and to consider reducing the inspiratory pressure Pinsp and / or the expiratory tidal volume VT is output, wherein a test phase with a reduced inspiratory pressure Pinsp should firstly be set, d. if CWIN,global and CLOSS,global are above the set threshold value, the recommendation to increase the PEEP and to consider reducing the inspiratory pressure Pinsp and / or expiratory tidal volume VT is output, wherein a test phase with a reduced inspiratory pressure Pinsp should firstly be set, and / or in the case of a PEEP setting that is reduced in the test phase (T1) relative to the reference phase (R), e. if CWIN,global and CLOSS,global are below the set threshold value, the recommendation not to change the ventilation settings and / or to reduce the PEEP is output, f. if CWIN,global is above the set threshold value and CLOSS,global is below the set threshold value, the recommendation to reduce the PEEP is output, g. if CWIN,global is below the set threshold value and CLOSS,global is above the set threshold value, the recommendation not to change the PEEP setting and / or to increase same and to consider a recruitment maneuver is output, h. if CWIN,global and CLOSS,global are above the set threshold value, the recommendation not to change the PEEP setting and to consider a recruitment maneuver and, if possible, to reduce the Pinsp and / or VT is output.

13. The system (1) according to at least one of the preceding claims, characterized in that, in the case of a Pinsp and / or VT setting that is increased in the test phase (T1) relative to the reference phase (R) and a. if CWIN,global and CLOSS,global are below the set threshold value, the recommendation not to change the ventilation settings is output, b. if CWIN,global is above the set threshold value and CLOSS,global is below the set threshold value, the recommendation to increase the PEEP is output, c. if CWIN,global is below the set threshold value and CLOSS,global is above the set threshold value, the recommendation to reduce the PEEP and / or Pinsp and / or VT setting is output, d. if CWIN,global and CLOSS,global are above the set threshold value, the recommendation to increase the PEEP and / or, if possible, to reduce the Pinsp and / or the tidal volume is output, and / or in the case of a Pinsp and / or VT setting that is reduced in the test phase (T1) relative to the reference phase (R) and e. if CWIN,global and CLOSS,global are below the set threshold value, the recommendation not to change the ventilation settings is output, f. if CWIN,global is above the set threshold value and CLOSS,global is below the set threshold value, the recommendation to reduce the PEEP and / or Pinsp and / or VT is output, g. if CWIN,global is below the set threshold value and CLOSS,global is above the set threshold value, the recommendation to increase the PEEP is output, h. if CWIN,global and CLOSS,global are above the set threshold value, the recommendation to increase the PEEP and, if possible, to reduce the Pinsp and / or the tidal volume is output.

14. The system (1) according to at least one of the preceding claims, characterized in that a finding is created based on the interpretation of the characteristic numbers CWIN,global and CLOSS,global and the report also contains at least one finding in addition to the recommendation.

15. The system (1) according to at least one of the preceding claims, characterized in that the control apparatus (22) is designed to automatically implement the output recommendations and to apply corresponding ventilation settings.

16. The system (1) according to at least one of the preceding claims, characterized in that the system (1) is configured to carry out the following method steps: a. acclimatizing (101) the organism (4) to ventilation settings of a reference phase R, b. measuring (102) impedances of the lung of the organism (4) during the reference phase R, c. acclimatizing (103) the organism (4) to ventilation settings of a test phase T1, d. measuring (104) impedances of the lung of the organism (4) during the test phase T1, e. calculating (105, 106) characteristic numbers CR,n and CT1,n from the impedance values from the step of measuring (102, 104), f. comparing (107) the characteristic numbers CR,n and CT1,n, g. classifying (108) the characteristic numbers CR,n and CT1,n into groups of numbers WIN and LOSS, h. calculating (109, 110) characteristic numbers CWIN,global and CLOSS,global, i. comparing (111, 112) the characteristic numbers CWIN,global and CLOSS,global with threshold values, j. evaluating (113), wherein the evaluating (113) at least comprises generating a graphical representation of the characteristic numbers CWIN,global and CLOSS,global and wherein the step of evaluating (113) optionally comprises creating a finding taking into account the characteristic numbers CWIN,global and CLOSS,global, k. recommending (114), wherein the recommending (114) at least comprises generating an alphanumerical output of recommendations with regard to the ventilation settings.