阅读说明：本技术 用于感测患者呼吸努力的系统 (System for sensing respiratory effort of a patient ) 是由 P·克雷迈尔 S·普勒茨 于 2020-02-20 设计创作，主要内容包括：本发明涉及一种用于感测活体(90)在呼吸和/或人工呼吸期间的电特性(40)的装置(100),包括用于人工呼吸的工具(20)和用于感测患者(90)的阻抗的工具(30)和至少一个控制单元(19),其中,在使用至少两个能导电的电极(31)的情况下进行所述阻抗(40)的感测,所述电极感测人体(90)的电特性,其中,用于感测所述阻抗的工具(30)设置为用于在呼吸和/或人工呼吸的时间进程中感测人体(90)的阻抗变化。(The invention relates to a device (100) for sensing an electrical property (40) of a living being (90) during respiration and/or artificial respiration, comprising means (20) for artificial respiration and means (30) for sensing an impedance of the patient (90) and at least one control unit (19), wherein the sensing of the impedance (40) is performed using at least two electrically conductive electrodes (31) which sense the electrical property of the human being (90), wherein the means (30) for sensing the impedance are arranged for sensing a change in the impedance of the human being (90) over the time course of the respiration and/or artificial respiration.)

1. Device (100) for sensing an electrical property (40) of a living body (90) during respiration and/or artificial respiration, comprising means (20) for artificial respiration and means (30) for sensing an impedance of the living body (90) and at least one control unit (19), wherein the sensing of the impedance (40) is carried out using at least two electrically conductive electrodes (31) which sense the electrical property of the living body (90), wherein means (30) are provided for sensing the impedance, which sense a change in the impedance of the living body (90) over the time course of the respiration and/or artificial respiration, wherein the means (20) for artificial respiration are provided for predetermining a breathing gas stroke for inhalation (28) and exhalation (27), characterized in that the control unit (19) at least temporarily analyzes and processes the information of the impedance (40) and the respiration and/or- Or information of artificial respiration (25, 26, 27, 28).

2. The device according to claim 1, characterized in that the control unit (19) displays and/or records the curve of the impedance (40) over the time course of the respiration and/or artificial respiration (25, 26, 27, 28).

3. Device according to at least one of the preceding claims, characterized in that the control unit determines a slope (45) of the (instantaneous) impedance (40), wherein the slope may have a positive or negative value (polarity of the slope) or may be equal to zero (46).

4. The device according to at least one of the preceding claims, characterized in that the control unit (19) is also configured for determining from the polarity of the slope whether inhalation or exhalation is present.

5. The device according to at least one of the preceding claims, characterized in that the control unit (19) is also configured for sensing a flat portion of the slope (45) of the impedance (40), wherein the controller interprets the flat portion of the slope (45) as approaching a maximum impedance (38) value or a minimum impedance (37) value.

6. The device according to at least one of the preceding claims, characterized in that the control unit (19) is also configured for, after having identified a flat portion of the slope (45) of the impedance (40), finding a transition to: the slope is substantially zero (46) in this point, and this point is interpreted as the value of the maximum impedance (38) or the value of the minimum impedance (37).

7. Device according to at least one of the preceding claims, characterized in that the control unit (19) evaluates the maximum value of the impedance (40) as the inhalation impedance (38).

8. The device according to at least one of the preceding claims, characterized in that the control unit (19) evaluates the minimum value of the impedance (40) as the expiratory impedance (37).

9. Device according to at least one of the preceding claims, characterized in that a threshold value (47, 48, 49) is determined and/or automatically ascertained for the inhalation impedance (38).

10. The device according to at least one of the preceding claims, characterized in that an impedance (40) below or above the threshold value (47, 48, 49) is evaluated as false trigger (38').

11. Device according to at least one of the preceding claims, characterized in that an inhalation impedance (38) below the threshold value (47, 48, 49) is evaluated as false trigger (38').

12. Device according to at least one of the preceding claims, characterized in that an impedance (40) above an impedance minimum (37) that has just passed in time and below the threshold (48, 49) is evaluated as a false trigger (38').

13. Device according to at least one of the preceding claims, characterized in that an error trigger (38') is recorded and stored and/or transmitted to the artificial respiration apparatus (20) and/or the impedance monitor (30).

14. Device according to at least one of the preceding claims, characterized in that the false trigger (38') is directly visualized or retrievable by a respiration apparatus (20) and/or the impedance monitor (30) in the region of the display (3).

15. Device according to at least one of the preceding claims, characterized in that the control unit (19) determines the frequency (35) of the respiration/artificial respiration from an alternation in the course of time of an increasing impedance (37) and a decreasing impedance (38).

16. The device according to at least one of the preceding claims, characterized in that the control unit (19) uses the final inhalation impedance (38) as a trigger criterion (34) for controlling a subsequent exhalation by the artificial respiration apparatus (20).

17. The device according to at least one of the preceding claims, characterized in that the control unit (19) uses the final expiratory impedance (37) as a trigger criterion (34) for controlling a subsequent inspiration by the artificial respiration apparatus (20).

18. Device according to at least one of the preceding claims, characterized in that the control unit (19) compares the frequency of a pre-set value (25) of artificial respiration with the natural frequency (35) of the patient determined by the impedance (37, 38, 40).

19. Device according to at least one of the preceding claims, characterized in that the control unit (19) compares the frequency of a given value (25) of artificial respiration with the natural frequency (35) of the patient, determined by the impedance (37, 38, 40) and/or the flow or pressure.

20. Device according to at least one of the preceding claims, characterized in that the control unit (19) compares the time points of the artificial respiration setpoint (25, 27, 28) with the time points of the impedance signal (35, 37, 38, 40).

21. Device according to at least one of the preceding claims, characterized in that the impedance information (34-39) is used by the control unit in order to evaluate the mechanical pressure load and volume load in the case of artificial respiration and to adapt the preset values of the artificial respiration accordingly.

22. Device according to at least one of the preceding claims, characterized in that a first PEEP pressure and here a first final expiratory impedance (37) are predefined for at least one breath and/or artificial respiration by the control unit (19) and a second PEEP pressure and here a second final expiratory impedance (37) are predefined for at least one breath and/or artificial respiration and at least the first and second (or any other) final expiratory impedance (37) are compared with each other and a recommendation for the operator of the artificial respiration apparatus is stored or output or an automatic selection and application of this PEEP pressure (41b) is made for that PEEP pressure (41b) which leads to a minimum final expiratory impedance (37 b).

23. Device according to at least one of the preceding claims, characterized in that the control unit (19) derives the impedance change (39) from at least one maximum value of the impedance and at least one minimum value of the impedance.

24. Device according to at least one of the preceding claims, characterized in that the impedance change (39) is derived and used in order to adaptively change at least one artificial respiration setting (42), such as pressure, PEEP, pressure control in expiration, frequency, volume and/or also sensitivity of the sensor, such that the impedance change (39) increases.

25. Device according to at least one of the preceding claims, characterized in that a first artificial respiration setting (42) and a first impedance change (39) is predefined for at least one respiration and/or artificial respiration and a second artificial respiration setting (42) and a second impedance change (39) is predefined for at least one respiration and/or artificial respiration and a second impedance change (39) is predefined and at least the first and second (or any other) impedance changes (39) are compared with each other and a recommendation for the operator of the artificial respiration apparatus is stored or output for that artificial respiration setting (42a) which leads to the highest impedance change (39a) or an automatic selection and application of this artificial respiration setting (42a) is made.

26. Device (100) for sensing electrical properties of a living being (90) during respiration and/or artificial respiration, comprising means (20) for artificial respiration and means (30) for sensing the impedance of the living being (90) and at least one control unit (19), wherein the sensing of the impedance (40) is carried out using at least two electrically conductive electrodes (31) which sense the electrical properties of the living being (90), wherein the means (30) for sensing the impedance are provided in order to sense changes in the impedance of the living being (90) over the time course of the respiration and/or artificial respiration, wherein the means (20) for artificial respiration are provided for predetermining a breathing gas stroke for inspiration (28) and expiration (27), characterized in that the control unit (19) at least temporarily analyzes and processes the information of the impedance (40) and the respiration and/or artificial respiration (25, 26, 27, 28), a first artificial respiration setting (42) and a first impedance change (39) being ascertained there for at least one breath and/or artificial respiration, and subsequently a second artificial respiration setting (42) and a second impedance change (39) being ascertained there for at least one breath and/or artificial respiration, and at least the first and second (or any other) impedance changes (39) being compared with one another, and a recommendation for an operator of an artificial respiration apparatus being stored or output or an automatic selection and application of the artificial respiration setting (42a) being made for that artificial respiration setting (42a) which causes the highest impedance change (39 a).

27. Device according to at least one of the preceding claims, characterized in that the device (100) is constructed in one piece and comprises means (20) for artificial respiration and means (30) for sensing the impedance and the control unit (19).

28. The device according to at least one of the preceding claims, characterized in that the device (100) is constructed in multiple parts and the means for artificial respiration (20) and the means for sensing impedance (30) and the control unit (19) are arranged spatially separately and functionally co-act.

Technical Field

The invention relates to a method for measuring a change in the electrical impedance of a body segment during respiration/artificial expiration using electrically conductive electrodes.

The invention also relates to a device which is suitable and designed for determining a change in the electrical impedance of a body segment during respiration/artificial respiration using electrically conductive electrodes.

The present invention relates generally to electrical impedance analysis (EI) and, for example, to Electrical Impedance Tomography (EIT). A common method of acquiring image data by EIT is to input a current into one pair of electrodes that can conduct electricity and to measure the potential that develops between the other pair of electrodes that can conduct electricity.

Background

EIT is used in the field of medical imaging as an alternative to computed tomography (CT scanning) or magnetic resonance tomography (MRI). EIT has the advantages of being non-invasive, free of radiation damage and long-term monitored over alternatives. And the image resolution is lower than in the case of the alternative method. In recent years, EIT technology has been further developed, and the purpose thereof is to further improve image resolution. DE102012224522 a1, WO 2002053029 a1 and US 5,544,662 disclose a method for improving the image resolution of EIT. In particular, EIT techniques are used to monitor and graphically illustrate the distribution of gases within the lungs of respiratory organisms and lungs.

The known EIT technique requires a complex electrode arrangement, a computing unit and a computing algorithm, which estimate the electrical impedance distribution in the chest from the voltages measured by means of the electrodes using an algorithm. Furthermore, EIT imaging algorithms and a large amount of computational power are required in order to produce a single image from the distribution of electrical impedance and then to generate multiple images in order to graphically show the changes during respiration.

Disclosure of Invention

The aim of the invention is to provide a method and a device for quickly and efficiently determining the Electrical Impedance (EI) and for detecting and evaluating only changes in the impedance. The invention is based on the recognition that a lot of information about artificial respiration is already available from the impedance change in the time course of respiration/artificial respiration. The invention is also based on the recognition that the information of the impedance changes in the time course of respiration/artificial respiration is more important than the acquisition of the image data.

Thereby overcoming the disadvantages of the prior art EIT.

The invention therefore relates to a method and a device for fast and efficient determination of the Electrical Impedance (EI) in the time course of respiration/artificial respiration without image information having to be obtained therefrom.

Device for sensing an electrical property of a living body during respiration and/or artificial respiration, comprising means for artificial respiration and means for sensing an impedance of the living body, wherein the sensing of the impedance is carried out using at least two electrically conductive electrodes which sense the electrical property of the living body, wherein the means for sensing the impedance are provided for sensing an impedance change of the living body in the temporal course of the respiration and/or artificial respiration, wherein the means for artificial respiration are provided for alternately predetermining a breathing gas path for inspiration and expiration in time, characterized in that the control unit at least temporarily analyzes the processing impedance information and the respiration and/or artificial respiration information.

The device is further characterized in that the control unit displays and/or records the impedance change in the time course of the respiration and/or artificial respiration.

The device is further characterized in that the control unit determines a slope of the (instantaneous) impedance, wherein the slope may have a positive value and a negative value (polarity of the slope) or may be equal to zero.

The device is further characterized in that the control unit is also configured to determine from the polarity of the slope whether inhalation or exhalation is present.

The control unit is further configured for identifying, among the slopes having the first polarity, a flat portion of the slope of the impedance (which may approach zero), and subsequently identifying the slope having the second polarity.

The control unit is further configured to interpret the polarity inversion of the slope as a region of a final expiratory impedance or a final inspiratory impedance.

The control unit is also designed to interpret the polarity reversal of the slope as a region of the trigger point in time.

The device is further characterized in that the control unit is further configured for sensing a flat portion of the slope of the impedance, wherein the control portion interprets the flat portion of the slope as a value close to a maximum or minimum impedance.

The device is further characterized in that the control unit is further configured to, after having identified the flat portion of the slope of the impedance, find a transition at a point where the slope is substantially zero, and interpret the point as a value of maximum or minimum impedance.

The device is further characterized in that the control unit evaluates the maximum value of the impedance as the inspiration impedance.

The device is further characterized in that the control unit evaluates the minimum value of the impedance as the expiratory impedance.

The device is further characterized in that a threshold value is determined and/or automatically determined for the inhalation impedance.

The apparatus is further characterized in that impedances below a threshold are evaluated as false triggers.

The device is further characterized in that an inhalation impedance below the threshold is evaluated as a false trigger.

The device is further characterized in that impedances above the impedance minimum that have passed immediately in time but below a threshold are evaluated as false triggers.

The device is further characterized in that false triggers are recorded and stored and/or transmitted to the respiration equipment and/or the impedance monitor.

The device is further characterized in that the false trigger is directly visualized or retrievable by the respiration device and/or the impedance monitor in the region of the display.

The device is further characterized in that the control unit determines the frequency of the respiration/artificial respiration from the transformation of the increasing and decreasing impedance and over the course of time.

The device is further characterized in that the control unit uses the final inhalation impedance as a trigger criterion for controlling a subsequent exhalation by the artificial respiration apparatus.

The device is further characterized in that the control unit uses the final expiratory impedance as a trigger criterion for controlling a subsequent inspiration by the artificial respiration apparatus.

The device is further characterized in that the control unit compares the frequency of the preset breathing setpoint with the natural frequency of the patient determined by the impedance.

The device is further characterized in that the control unit compares the frequency of the preset breathing setpoint with the natural frequency of the patient determined by the impedance and/or the flow or pressure.

The device is further characterized in that the control unit compares the time point of the preset value of the artificial respiration with the time point of the impedance signal.

The device is further characterized in that the impedance information is used by the control unit in order to analyze the pressure load and the volume load of the treatment machine in the case of artificial respiration and to adapt the preset values of the artificial respiration accordingly.

The device is further characterized in that a first PEEP pressure is predefined for at least one breath and/or artificial respiration by the control unit and a first final expiratory impedance is determined, and a second PEEP pressure is predefined for at least one breath and/or artificial respiration and a second final expiratory impedance is determined, and at least the first and the second (or any other) final expiratory impedance are compared with each other, and a recommendation for the operator of the artificial respiration apparatus or an automatic selection and application of the PEEP pressure is stored or output for the PEEP pressure which leads to the smallest final expiratory impedance.

The device is further characterized in that the control unit determines the impedance change from at least one maximum value of the impedance and at least one minimum value of the impedance.

The device is further characterized in that the impedance change is determined and used in order to adaptively change at least one artificial respiration setting (42), such as pressure, PEEP, pressure control in expiration, frequency, volume and/or also the sensitivity of the sensor, such that the impedance change increases.

The device is further characterized in that a first artificial respiration setting is predefined for at least one respiration and/or respiration and a first impedance change is ascertained there, and subsequently a second artificial respiration setting is predefined for at least one respiration and/or respiration and a second impedance change is ascertained there, and at least the first and the second (or any other) impedance changes are compared with one another and a recommendation for the operator of the artificial respiration apparatus or an automatic selection and application of the artificial respiration setting is stored or output for the artificial respiration setting which leads to the highest impedance change.

The invention further relates to a device for sensing an electrical property of a living body during respiration and/or artificial respiration, comprising means for artificial respiration and means for sensing an impedance of the living body, wherein the sensing of the impedance is carried out using at least two electrically conductive electrodes which sense the electrical property of the living body, wherein the means for sensing the impedance are provided for sensing an impedance change of the living body over the course of time of the respiration and/or artificial respiration, wherein the means for artificial respiration are provided for predetermining a breathing gas path for inspiration and expiration, characterized in that the control unit at least temporarily analyzes and processes the impedance information and the respiration and/or artificial respiration information, the first artificial respiration setting being predetermined for at least one respiration and/or artificial respiration and the first impedance change being ascertained there, and subsequently a second artificial respiration setting is predefined for at least one breath and/or artificial respiration and a second impedance change is ascertained there and at least the first and/or the second (or any other) impedance changes are compared with one another and a recommendation for the operator of the artificial respiration apparatus or an automatic selection and application of the artificial respiration setting is stored or output for the artificial respiration setting which causes the highest impedance change.

The device is further characterized in that the device is constructed in one piece and comprises means for artificial respiration and means for sensing impedance and a control unit.

The device is also characterized in that the device is designed in multiple parts, and the means for artificial respiration and the means for sensing impedance and the control unit are arranged spatially separately and functionally cooperate.

The invention further relates to a device for sensing an electrical property of a living being during respiration and/or artificial respiration, comprising means for artificial respiration and means for sensing an impedance of the living being, wherein the sensing of the impedance is performed using at least two electrically conductive electrodes which sense the electrical property of the living being, wherein the means for sensing the impedance are arranged for sensing an impedance change of the living being over the time course of the respiration and/or artificial respiration, wherein the means for artificial respiration are arranged for predetermining a breathing gas stroke for inspiration and expiration, characterized in that the control unit determines a slope of the (instantaneous) impedance, wherein the slope may have a positive value and a negative value (polarity of the slope) or may be equal to zero.

Alternatively and/or additionally, the invention also relates to a method and a device for quickly and efficiently determining the Electrical Impedance (EI) by determining image information of the electrical impedance (distribution) during the time course of respiration/artificial respiration.

Drawings

Fig. 1 shows a device according to the invention in a schematic representation;

fig. 2 shows the basic structure of an artificial respiration apparatus in a schematic representation;

fig. 3 schematically shows a variation of the impedance of the chest during breathing;

fig. 4 schematically shows the change of the impedance of the chest during breathing in the area of the display and the control unit; and

fig. 5 schematically shows the variation of the impedance of the chest during breathing.

Detailed Description

Fig. 1 schematically shows a device (100) having a respiration apparatus (20) arranged on a patient (90) and an impedance monitor (30), which may be part of the respiration apparatus or a separate apparatus that preferably interacts functionally with the respiration apparatus. The measurement of the impedance (40) is based on the use of electrically conductive electrodes (31) which actively or passively sense the electrical behavior of the human body (90).

The impedance (40) measured or determined continuously or in stages allows changes in the thoracic impedance to be evaluated during breathing or in the case of artificial breathing.

In an impedance monitor (30) according to the invention, a current is applied to the skin of the chest in order to establish an electric field in the chest. According to the invention, 2, 4, 8, 16, 32 or more electrodes (31) are arranged around the thorax and are used to measure the potentials caused by the field. The measured voltage is used in order to find the change in electrical impedance of the thorax, using an algorithm. Discarding the determination of the impedance distribution and the laborious calculation of the discarding of the image data enables a very fast and cost-effective application of the impedance information.

According to the invention, the change in impedance is determined relative to a base or reference determination. For example, the change in impedance is determined during respiration/artificial respiration, wherein the impedance increases with inspiration and decreases with expiration. This relative approach eliminates errors arising from assumptions about chest shape, electrode location, or body composition as is common in EIT techniques.

Therefore, the impedance change does not show its absolute value.

According to the invention, a limited amount of current (typically 0.5-100mA) is used, since only a small current achieves a maximum signal-to-noise ratio. The electrodes are distributed, for example, at equidistant distances, at discrete physical locations around or on the thorax.

The electrodes (31) may be insulated gel electrodes or ECG electrodes, which are connected to a remotely located electrical circuit by a single shielded cable.

Fig. 2 shows the basic structure of the artificial respiration apparatus (20). An operating element (2) and/or an operating and information system (3) are arranged in the region of the device housing (1). The connecting hoses (5) are connected through coupling pieces (4). An additional pressure measuring tube (6) can run along the connecting tube (5), which can be connected to the device housing (1) via a pressure supply sleeve (7). In order to be able to transmit data, the device housing (1) has at least one interface (8, 18). Furthermore, the humidifier (21) or the nebulizer (22) may be adapted. The artificial respiration apparatus has a source of respiration gas (17).

In the region of the extension of the connection tube (5) facing away from the device housing (1), an exhalation element (9) is arranged, for example. An exhalation valve may also be used.

The artificial respiration apparatus (20) can be designed as a sleep therapy apparatus, a high-flow apparatus, an anesthesia apparatus, a clinic or a home or emergency respiration apparatus.

Furthermore, fig. 2 shows a patient interface configured as a breathing mask (10). The fixing in the head region of the patient can be achieved by a hood (11). The patient interface (10) has a coupling element (12) in the region of its extension facing the connection hose (5). The patient interface can also be configured, for example, as a tube or other interface.

Data, for example dead space volume, can be input and/or output via the interface (8, 18). These interfaces may be implemented as cable connections to ground, as infrared interfaces, as bluetooth interfaces, or USB. Preferably, a card slot is also provided. The interface (8) may also be implemented as a LAN interface or as another interface for connecting to the internet or to a patient monitor or EI instrument (30). In the area of the device housing, the oxygen access valve can be adapted to a device for artificial respiration. It is conceivable to accumulate additional respiratory gas with oxygen in order to improve the patient supply.

The inventive respirator (20) is designed in such a way that it can be connected to a patient via a hose and a patient interface in order to provide respiration. The respiration apparatus comprises a source of respiration gas (17), which is designed, for example, as an electric motor with a fan wheel or as a compressed gas connection with at least one valve. The respiration apparatus has a device for determining the pressure and/or flow and/or volume (23, 24) of the respiratory gas. The control unit (19) is designed such that it determines the breathing gas parameter, for example, for each breathing cycle on the basis of predetermined values and/or measurement signals for the parameters pressure and/or flow and/or volume, and adjusts the breathing gas source such that the breathing gas parameter is applied. The control unit can controllably preset and/or at least partially assist or adaptively preset the parameters of the artificial respiration taking into account the measurement signal.

The control unit (19) is designed, for example, such that it determines the current pressure and/or flow rate and/or volume of the breathing gas. The current value may be displayed on a display (3).

Furthermore, the control unit (19) compares such user-specified parameter values (such as the upper and lower pressure limits or the maximum tolerable number of breathlessness per time unit or the maximum tolerable leakage) with the current values and generates user information for deviations from the specified values. The user information is preferably visualized graphically by the operating and information system (fig. 3).

For this purpose, the respirator (20) has a pressure measurement input (pneumatic or electronic or optical) and a pressure sensor (23).

The control unit (19) is provided and designed, for example, to recognize a change in impedance and to control the respiration apparatus in order to specify respiration parameters.

When a threshold value for the impedance is exceeded or undershot, the control unit (19) generates a control signal for the artificial respiration device (20), for example, for a predetermined inspiratory or expiratory breathing gas pressure. If the threshold value for the impedance is exceeded or undershot, the control unit (19) generates a control signal for the artificial respiration device (20) for ending the predetermination of the breathing gas pressure for inhalation or exhalation, for example, instead.

Fig. 3 schematically shows the variation of the impedance (40) of the chest during breathing. The change in the sum signal of the impedance is shown, wherein the sum signal rises with inspiration (38, 38') and falls with expiration. Here, the impedance is plotted as a relative impedance without units (40). The impedance monitor (30) senses the impedance (40) of, for example, the chest at a frequency of, for example, 6-200 measurements per second. The software generates a relative impedance (40) from the measurements.

The impedance alternates between the values of the maximum impedance (38) and the minimum impedance (37) at the rhythm of breathing/artificial breathing. The continuous recording of the impedance allows to determine the slope (45) of the impedance at each point in time (instant). Here, the slope may have a positive value and a negative value (polarity of the slope). It can be seen that the slope (45) decreases as it approaches the value of the maximum impedance (38) or the minimum impedance (37) and reaches a point in time at which the slope is substantially zero (46) and then increases again.

The control unit (19) is therefore preferably designed to determine the slope (45) of the impedance (40). The control unit (19) is also designed to determine the polarity of the slope.

Therefore, the control unit (19) is preferably also configured for sensing a change in the slope (45) of the impedance (40). The control unit (19) is further configured to sense a flat of a slope (45) of the impedance (40), wherein the control section interprets the flat of the slope (45) as a value close to the maximum impedance (38) or the minimum impedance (37). The control unit (19) is also configured to determine, after detecting a flat portion of the slope (45) of the impedance (40), a transition at a point at which the slope is substantially zero (46) and subsequently rises again. The control unit (19) is also configured to interpret a point at which the slope is substantially zero (46) as the final expiratory impedance (37) and/or the final expiratory impedance (38). The controller (19) is further configured to identify a flat portion of the slope (45) of the impedance (40) in the slope having the first polarity (which may approach zero (46)) and subsequently identify a slope having the second polarity. The control unit (19) is also configured to interpret the change in polarity of the slope as a region of the final expiratory impedance (37) or the final inspiratory impedance (38). The control unit (19) is also designed to interpret the polarity reversal of the slope as a region of the trigger point in time. The control unit (19) is further configured for determining from the polarity of the slope whether inhalation or exhalation is present.

For further analysis processing, for example, the final expiratory impedance (37) and/or the final inspiratory impedance (38) are observed. The final inspiratory impedance (38) is the impedance at the end of inspiration. A threshold (48) may be determined and/or automatically determined for the inspiratory impedance (38). The inhalation impedance (38) below the threshold (48) is evaluated as a false trigger (38'). Here, the patient's effort to inhale does not result in an inhalation (by the artificial respiration apparatus).

Similarly, a threshold (49) for minimum expiratory impedance (37) may also be defined and used. The threshold may also be an average impedance (47). According to the invention, false triggers (38') are recorded and stored and/or transmitted to the respiration device (20) and/or the impedance monitor (30). The error trigger (38') can be directly visualized or retrievable by the respiration apparatus (20) and/or the impedance monitor (30) in the region of the display (3).

According to the invention, the error triggers (38 ') can be stored and output as a number of error triggers (38') per unit of time. According to the invention, the threshold value (48, 49) is preset and/or can be determined by the user, and/or can be automatically adapted at least partially depending on the maximum impedance. The threshold (48, 49) may be a percentage of the maximum impedance (38), for example in the range of 66% to 33% of the maximum impedance (38), or in the range of 75% or less of the maximum impedance (38), or in the range of 50% or less of the maximum impedance. The threshold value (48, 49) can also be determined as a function of the minimum impedance (37), for example the minimum impedance (37) must exceed at least 40% or exceed at least 70% in order to conclude that there is no false triggering (38').

According to the invention, it is also contemplated to use false triggers (38 ') in order to adaptively change the artificial respiration settings, such as pressure, frequency, volume and sensitivity of the sensor, such that the number of false triggers (38') is reduced.

Fig. 4 shows schematically in the top the change in the impedance (40) of the chest during breathing in the region of the display (3). For further analysis processing, for example, the final expiratory impedance (37), the final inspiratory impedance (38) are shown. Furthermore, the display (2) shows the profile of the measured values of the sensors or the preset values of the respirator, which corresponds to the pressure profile with the inhalation pressure (28) and the exhalation pressure (27). Also inserted is a time point information (t) which visually connects the impedance curve to the curve of the set value of the artificial respiration. In particular, in the lower part of fig. 4, a control unit (19) can be identified, which collects and processes the necessary measured values and information for displaying the impedance (40) and the respiration/respiration profile.

Fig. 5 schematically shows the variation of the impedance (40) of the chest during breathing. Here, the impedance is plotted as a relative impedance without units (40). The impedance monitor (30) senses the impedance (40), e.g., of the chest, at a frequency of, e.g., 60 measurements per second (or in the range of 20-100). The software establishes the relative impedance (40) from the measured values and reproduces it, for example, as a numerical value. For further analysis processing, for example, the final expiratory impedance (37), the final inspiratory impedance (38) and the impedance change (39) are used.

The impedance change (39) is the difference of the final expiratory impedance (lowest) and the final inspiratory impedance (highest); the impedance change represents a change in thoracic impedance within one breath. An increase in the impedance change (39) indicates an increase in the breathing volume. Ventilation of the lungs is roughly simplified.

The final expiratory impedance (37) is the impedance at the end of expiration. The final inspiratory impedance (38) is the impedance at the end of inspiration.

According to the invention, it is also conceivable to use the final expiratory impedance (37) in order to adaptively change the artificial respiration settings, such as pressure, PEEP, pressure control in expiration, frequency, volume and/or sensitivity of the sensor, such that the final expiratory impedance (37) is reduced.

According to the invention, the use of the final expiratory impedance (37) for setting the optimal PEEP is also considered. For this purpose, a first PEEP pressure is predefined for at least one breath or a plurality of breaths, and a first final expiratory impedance (37) is determined. Subsequently, a second PEEP pressure is predefined for at least one breath or a plurality of breaths and a second final expiratory impedance is determined (37). According to the invention, a plurality of PEEP pressures can be predefined in this sense and a plurality of corresponding final expiratory impedances (37) can be determined. Subsequently, at least the first and second (or any other) final expiratory impedance (37) are compared with each other. For that PEEP pressure (41best) which results in the lowest final expiratory impedance (37best), a recommendation to the operator of the artificial respiration apparatus is stored or output, or an automatic selection and application of that PEEP pressure (41best) is made.

For this purpose, different PEEP pressures of the system are predefined for at least one breath or for a plurality of breaths.

According to the invention, it is also contemplated to use the final inspiratory impedance (38) in order to adaptively change the artificial respiration settings, such as pressure, PEEP, pressure control in inspiration, frequency, volume and/or sensitivity of the sensor, such that the final inspiratory impedance (38) is increased.

The impedance monitor may determine the frequency of breathing/artificial breathing (35) from the alternation of the final expiratory impedance (37) and the final inspiratory impedance (38) over the course of time.

The highest final inspiratory impedance (38) may be used as a trigger criterion (34) for controlling a subsequent exhalation through the artificial respiration apparatus (20). The lowest final expiratory impedance (37) can be used as a trigger criterion (34) for controlling a subsequent inspiration by the artificial respiration apparatus (20).

The impedance changes (39) reflect ventilation changes in the lungs. According to the invention, it is possible to perform a view of the entire lung and to perform separate analysis processes for the ventral and dorsal side or arbitrary lung segments.

An increase in the impedance change (39) reflects an increase in respiratory volume.

It is also contemplated according to the invention to use impedance changes (39) in order to adaptively change the artificial respiration settings, such as pressure, PEEP, pressure control in exhalation, frequency, volume and/or sensitivity of the sensor, such that the impedance change (39) increases.

For this purpose, a first PEEP pressure is predefined for at least one breath or a plurality of breaths and a first impedance change (39) is determined. Subsequently, a second PEEP pressure is predefined for at least one breath or a plurality of breaths and a second impedance change is determined (39). According to the invention, a plurality of PEEP pressures can be predefined and a plurality of corresponding impedance changes (39) can be determined. Subsequently, at least the first and second (or any other) impedance changes (39) are compared with each other. For that PEEP pressure (41c) which causes the highest impedance change (39c), a recommendation to the operator of the artificial respiration apparatus is stored or output or an automatic selection and application of the PEEP pressure (41c) is made.

According to the invention, it is also contemplated to use an impedance variation (39) in order to adaptively change at least one artificial respiration setting (42), such as pressure, PEEP, pressure control in exhalation, frequency, volume and/or sensitivity of the sensor, such that the impedance variation (39) increases.

For this purpose, a first artificial respiration setting (42) is predefined for at least one breath or a plurality of breaths and a first impedance change (39) is determined in the process. Subsequently, a second artificial respiration setting (42) is predefined for at least one breath or a plurality of breaths and a second impedance change (39) is determined. According to the invention, a plurality of respiration settings (42) can be predefined and a plurality of corresponding impedance changes (39) can be determined. Subsequently, at least the first and second (or any other) impedance changes (39) are compared with each other. For that artificial respiration pressure setting (42a) which causes the highest impedance change (39a), a recommendation to the operator of the artificial respiration apparatus is stored or output or an automatic selection and application of the artificial respiration setting (42a) is made.