DEVICE FOR SUPPORTIVE RESPIRATION OF A LIVING BEING AND COMPUTER PROGRAM

Abstract

The invention relates to a device (1) for supportive respiration of a living being (3), said device having a sensor arrangement, a programmable control unit (10) and an air conveyance unit (6), which is controllable by the control unit (10). The sensor arrangement has a pressure sensor (9) and an air flow sensor (11), which are designed for the temporally successive detection of respiratory pressure values and respiratory air flow values of the living being (3). The programmable control unit (10) is designed to evaluate respiratory air pressure profiles and respiratory air flow profiles formed from the temporally successive respiratory pressure values and respiratory air flow values detected by the sensor arrangement In order to provide respiration for the living being (3) which is in particular comfortable and individually adapted to the current needs of the living being (3), according to the invention the programmable control unit (10) is designed to detect unsuccessful respiratory movements of the living being (3) and the cause thereof on the basis of characteristic features of the respiratory pressure profiles and/or the respiratory air flow profiles. The invention furthermore relates to a computer program having program code means, designed to carry out a method for supportive respiration of a living being (3) by means of a respirator device (1) when the computer program is executed on a computer unit of the respirator device (1).

Claims

1. A device for supportive ventilation of a living being, comprising: a sensor arrangement, a programmable control unit, and an air delivery unit controllable by the programmable control unit, wherein the sensor arrangement comprises a pressure sensor and an air flow sensor which are respectively designed for temporally successive detection of respiratory air pressure values and temporally successive detection of respiratory air flow values of the living being, and wherein the programmable control unit is designed to evaluate respiratory air pressure curves and respiratory air flow curves formed from the temporally successive respiratory air pressure values and the temporally successive respiratory air flow values detected by the sensor arrangement, and wherein the programmable control unit is designed to detect frustrated breathing movements of the living being based on characteristic features of the respiratory air pressure curves and/or the respiratory air flow curves.

2. The device as claimed in claim 1, wherein the characteristic features are maxima, minima, turning points, saddle points, amplitudes, integrals and/or derivatives at predefined time points and/or time segments of the respiratory air pressure curves and/or the respiratory air flow curves.

3. The device as claimed in claim 1 wherein the characteristic features comprise characteristic deviations from predefined reference respiratory air pressure curves and/or predefined reference respiratory air flow curves.

4. The device as claimed in claim 1 wherein the programmable control unit comprises a memory unit for storing predefined reference respiratory air pressure curves and/or predefined reference respiratory air flow curves and/or reference features for characteristic features of frustrated breathing movements.

5. The device as claimed in claim 4, wherein the memory unit has various disease-specific reference respiratory air pressure curves and/or various disease-specific reference respiratory air flow curves and/or various disease-specific reference features for characteristic features of frustrated breathing movements.

6. The device as claimed in claim 1 wherein the programmable control unit is designed to distinguish between a frustrated breathing movement occurring as a result of an intrinsic PEEP of the living being and a frustrated breathing movement occurring as a result of a trigger insufficiency based on the characteristic features of the respiratory air pressure curves and/or the respiratory air flow curves.

7. The device as claimed in claim 1 wherein the programmable control unit is designed to distinguish between a frustrated breathing movement occurring as a result of a leakage-related trigger insufficiency and a frustrated breathing movement occurring as a result of a parameter-related trigger insufficiency based on the characteristic features of the respiratory air pressure curves and/or respiratory air flow curves.

8. The device as claimed in claim 1 wherein the programmable control unit is designed to detect a frustrated breathing movement based on a time point a time span and/or a form of a respiratory air pressure increase or reduction and/or a respiratory air flow increase or reduction in the respiratory air pressure curves and/or the respiratory air flow curves.

9. The device as claimed in claim 1 wherein the programmable control unit is designed to distinguish between a frustrated breathing movement occurring as a result of an intrinsic PEEP of the living being and a frustrated breathing movement occurring as a result of a trigger insufficiency based on the characteristic features of the respiratory air flow curves and related characteristic features of the respiratory air pressure curves.

10. The device as claimed in claim 1 wherein the programmable control unit is designed to perform oscillometric airway resistance measurements.

11. The device as claimed in claim 6 wherein the programmable control unit is designed to determine a frequency and/or an intensity of an intrinsic PEEP or of the trigger insufficiency.

12. The device as claimed in claim 11, wherein the programmable control unit is designed to output an acoustic, optical and/or haptic alarm signal when a predefined threshold value for the frequency and/or the intensity of the intrinsic PEEP or of the trigger insufficiency is exceeded.

13. The device as claimed in claim 1 wherein the programmable control unit is designed to automatically vary control parameters of the air delivery unit upon detection of a frustrated breathing movement.

14. The device as claimed in claim 13, wherein the programmable control unit is designed for continuous regulating automatic variation of control parameters of the air delivery unit in order to reduce and/or eliminate the features of the respiratory air pressure curves and/or the respiratory air flow curves that are characteristic of the frustrated breathing movement.

15. The device as claimed in claim 13 wherein the programmable control unit is designed to automatically vary control parameters of the air delivery unit in order to reduce the features of the respiratory air pressure curves and/or the respiratory air flow curves that are characteristic of the frustrated breathing movement, according to a predefined intrinsic minimum PEEP.

16. The device as claimed in claim 15, wherein the programmable control unit is designed to determine a predefined intrinsic minimum PEEP on the basis of pCO2 measurements.

17. The device as claimed in claim 13 wherein a control parameter predefined by the programmable control unit functions as an inspiration trigger or an expiration trigger for changing the device from an inspiration mode to an expiration mode, or vice versa.

18. The device as claimed in claim 13 wherein a control parameter predefined by the programmable control unit functions as a respiratory air pressure curve and/or a respiratory air flow curve of the air delivered by the air delivery unit.

19. The device as claimed in claim 13 wherein a control parameter predefined by the programmable control unit functions as a counterpressure and/or a counterpressure curve and/or a counterpressure amplitude and/or a counterpressure wait time during the expiration phase.

20. The device as claimed in claim 19, wherein the counterpressure amplitude and/or the counterpressure wait time is settable as a function of each other and/or as a function of an IPAP value or a IPAP value range and/or as a function of a differential pressure of IPAP to EPAP.

21. The device as claimed in claim 1 wherein the programmable control unit is designed such that upon detection of a frustrated breathing movement occurring as a result of an intrinsic PEEP of the living being, the programmable control unit automatically reduces a backup frequency and/or reduces an IPAP value and/or reduces a maximum inspiration time to automatically increase an expiration trigger sensitivity after elimination of a frustrated breathing movement occurring as a result of an intrinsic PEEP of the living being, and/or the programmable control unit automatically increases the backup frequency and/or increases the IPAP value and/or increases the maximum inspiration time to automatically reduce the expiration trigger sensitivity after elimination of a frustrated breathing movement occurring as a result of the intrinsic PEEP of the living being.

22. The device as claimed in claim 1 wherein the programmable control unit comprises a pattern recognition unit for recognizing characteristic features of the respiratory air pressure curves and/or the respiratory air flow curves.

23. A computer program with program code encoded on a non-transient storage medium designed to carry out a method for supportive ventilation of a living being with a ventilator when the computer program is executed on a computing unit of the ventilator, wherein a pressure sensor and an air flow sensor of the ventilator respectively detect temporally successive respiratory air pressure values and temporally successive respiratory air flow values of the living being and a programmable control unit of the ventilator evaluates respiratory air pressure curves and respiratory air flow curves formed from the respiratory air pressure values and the respiratory air flow values, and wherein frustrated breathing movements of the living being are detected based on characteristic features of the respiratory air pressure curves and/or respiratory air flow curves.

24. The device as claimed in claim 8 wherein the programmable control unit distinguishes between a frustrated breathing movement occurring as a result of an intrinsic PEEP of the living being and a frustrated breathing movement occurring as a result of a trigger insufficiency based on the time point, the time span and/or the form of the respiratory air pressure increase or reduction and/or the respiratory air flow increase or reduction in the respiratory air pressure curves and/or the respiratory air flow curves

Description

[0075] The invention is explained in more detail below on the basis of an exemplary embodiment and with reference to the accompanying schematic drawings, in which:

[0076] FIG. 1 shows a device for supportive ventilation of a living being;

[0077] FIG. 2 shows a normal respiratory air pressure curve and respiratory air flow curve;

[0078] FIGS. 3-5 show respiratory air pressure curves and respiratory air flow curves over time during a breathing cycle with detectable frustrated breathing movements and during a breathing cycle without detectable frustrated breathing movements;

[0079] FIGS. 6-8 show respiratory air pressure curves over time during a breathing cycle with an activated deflation function of the device; and

[0080] FIG. 9 shows an actually recorded respiratory air pressure curve and respiratory air flow curve with detectable frustrated breathing movements.

[0081] FIG. 1 shows a device 1 for supportive ventilation of a living being 3. The device 1 has a hose 8 and a breathing mask 2 or another suitable interface for connecting the device 1 to the living being 3. The breathing mask 2 is for this purpose attachable, for example, to the mouth and/or nose or to deeper airways of the living being 3. The breathing mask 2 has an outlet 4 which is open to the atmosphere and which is connected to the hose 8 via a throttle site 5. In this way, a defined leakage can be provided in the breathing mask 2.

[0082] The device 1 has a controllable air delivery unit 6 with a fan for generating the overpressure, required for the supportive ventilation, in the respiratory organs of the living being 3. For example, via the air delivery unit 6, air is sucked in from an air inlet 7 connected to the atmosphere and, suitably compressed via the hose 8, is delivered to the breathing mask 2 and thus to the living being 3.

[0083] The device 1 has a sensor arrangement with a pressure sensor 9 and an air flow sensor 11, which are designed for temporally successive detection of respiratory air pressure values and respiratory air flow values of the living being 3. Alternatively or in addition, the air delivery unit 6 can have an integrated pneumotachographic measuring arrangement for measurement of pressure and/or volumetric flow.

[0084] The pressure sensor 9, the air flow sensor 11 and the air delivery unit 6 are connected to a programmable control unit 10 via electrical lines. The programmable control unit 10 evaluates the respiratory air pressure curves and respiratory air flow curves formed from the respiratory air pressure values and respiratory air flow values that are detected over time by the pressure sensor 9 and the air flow sensor 11. The programmable control unit 10 is designed to detect frustrated breathing movements of the living being 3 on the basis of characteristic features of the respiratory air pressure curves and/or respiratory air flow curves. The programmable control unit is moreover designed to establish the cause(s) of the frustrated breathing movements and, if necessary, to take countermeasures to reduce or avoid the frustrated breathing movements. For this purpose, it can optionally have a suitable memory unit, suitable software, transmission means and/or a pattern recognition unit (in each case not shown in any more detail).

[0085] FIG. 2 shows, in a highly schematic manner, a normal respiratory air pressure curve and respiratory air flow curve, as can ideally be measured in a healthy living being under ventilation. The upper diagram shows a respiratory air pressure curve as a function of the pressure p over the time t. The middle diagram shows a respiratory air flow curve as a function of the volumetric flow v over the time t. The lower diagram shows the time sequence of ventilation modes of the device 1, here an inspiration mode INSP and an expiration mode EXSP, during a breathing cycle as a result of an automatic detection of the ventilation phase T.sub.I, T.sub.E of the living being 3 by the device 1. All that is shown is one complete breathing cycle with an inspiration phase T.sub.I and an expiration phase T.sub.E, which breathing cycle can be seen as representative of preceding and subsequent breathing cycles. The breathing cycle begins at the time point t.sub.0 and ends at the time point t.sub.2. The change from an inspiration phase T.sub.I to an expiration phase T.sub.E takes place after approximately half of the breathing cycle at the time point t.sub.1. However, the time point t.sub.1 can also lie considerably closer to t.sub.0, such that the ratio of T.sub.I to T.sub.E can also assume values of 1:2 to 1:4 or can be even smaller. In individual cases, the time point t.sub.1 can also lie closer to t.sub.2. It can be seen in FIG. 2 that the respiratory air pressure in the inspiration phase T.sub.I is initially steadily increased to the IPAP value p.sub.I, then assumes an approximately constant pressure level at the IPAP value p.sub.I over a certain time span and, still in the inspiration phase T.sub.I, steadily decreases. By contrast, in the expiration phase T.sub.E, there is no longer a build-up of pressure, but instead a constant pressure at the basal pressure level of the breathing cycle, in the present case at the level of the EPAP value P.sub.E. It can also be seen in FIG. 2 that the respiratory air flow initially increases steadily in the inspiration phase T.sub.I and, after reaching a local maximum, decreases steadily still in the inspiration phase T.sub.I. At the end of the inspiration phase T.sub.I or at the beginning of the expiration phase T.sub.E, i.e. approximately at the time point t.sub.1, the respiratory air flow changes to a value range below the initial level of the inhalation air flow, which illustrates the change in the direction of the respiratory flow of the living being. After a local minimum is reached, the respiratory air flow increases again until it has reached its initial value at the beginning of the breathing cycle and moves on to the next breathing cycle. For example, an inspiration trigger of the device 1 detects the end of an expiration T.sub.E and/or the beginning of an inspiration T.sub.I of the living being 3, idealized here at the time point t.sub.0, and causes the programmable control unit 10 to switch on an inspiration mode INSP of the control unit 10. In the inspiration mode INSP, for example, the air delivery unit 6 can generate an overpressure, supporting the inspiration by the living being 3, with a predefined pressure curve. For example, an expiration trigger of the device 1 detects the end of an inspiration T.sub.I and/or the beginning of an expiration T.sub.E of the living being 3, idealized here at the time point t.sub.1, and causes the programmable control unit 10 to switch on an expiration mode EXSP of the control unit 10. In the expiration mode EXSP, for example, the air delivery unit 6 can generate an overpressure, supporting the expiration by the living being 3, with a predefined pressure curve. Ideally at the time point t.sub.2, the control unit 10 ends the expiration mode EXSP, for example on account of a signal from the inspiration trigger. The idealized representation of the change-over times between the two modes does not take account of any technically related delay times, for example electronic switching times. The beginning or the end of the inspiration mode INSP or expiration mode EXSP are not rigidly predefined by the control unit 10, but are dynamically adapted to the ventilation phases T.sub.I, T.sub.E of the living being 3 by the detection of a corresponding respiratory effort of the living being 3.

[0086] FIGS. 3 to 5 show respiratory air pressure curves and respiratory air flow curves, each with a breathing cycle consisting of the modes INSP and EXSP with a frustrated breathing movement, and, for comparison, a subsequent breathing cycle without a frustrated breathing movement. The curves shown here have different characteristic features or feature combinations M.sub.1 to M.sub.4 for frustrated breathing movements of the living being 3. It should be noted that the characteristic features or feature combinations M.sub.1 to M.sub.4 shown here are highly schematic in order to enhance understanding, and they only represent selected examples of features that have already been identified in tests as being characteristic.

[0087] In FIGS. 3 to 5, the first breathing cycle, which has a frustrated breathing movement, in each case begins at the time point t.sub.0 and ends at the time point t.sub.2. The change from an inspiration phase T.sub.I to an expiration phase T.sub.E of the living being 3 takes place at the time point t.sub.1. Between the time points t.sub.3 and t.sub.4, a characteristic feature M.sub.1, M.sub.2, M.sub.3, M.sub.4 occurs in the respiratory air pressure curve and/or respiratory air flow curve. The second breathing cycle, which has no frustrated breathing movement, in each case begins at the time point t.sub.2 and ends at the time point t.sub.6. The change from an inspiration phase T.sub.I to an expiration phase T.sub.E of the living being 3 takes place at the time point t.sub.5.

[0088] It can be seen in FIG. 3 that, within the expiration phase T.sub.E during the increase in the respiratory air flow curve between the time points t.sub.3 and t.sub.4, a respiratory air flow increase, identified as a bulge, occurs as characteristic feature M.sub.1. In the respiratory air pressure curve, a respiratory air pressure increase, identified as a bulge, can be seen as a further characteristic feature M.sub.2 substantially at the same time as the characteristic feature M.sub.1. The features M.sub.1 and M.sub.2 can each already be considered individually as characteristic features of a frustrated breathing movement. However, they can also form a common characteristic feature of a frustrated breathing movement and can be evaluated coherently or in relation to each other. For example, it can be specified in the programmable control unit 10 that, in the sense of a two-factor dependency, the presence of a frustrated breathing movement is inferred only when the characteristic features M.sub.1 and M.sub.2 occur together.

[0089] It has been found that the characteristic features M.sub.1 and M.sub.2 are not only characteristic of a frustrated breathing movement in general, but in particular of a frustrated breathing movement as a result of a trigger insufficiency. If the programmable control unit 10 detects a respiratory air flow increase, present as a bulge, in the respiratory air flow curve and also a substantially simultaneous respiratory air pressure increase in the form of a bulge, which preferably also have substantially the same or similar gradients and/or integrals, the control unit 10 infers the presence of a frustrated breathing movement as a result of a trigger insufficiency.

[0090] It has also been found that the characteristic features M.sub.1 and M.sub.2 are not only characteristic of a trigger insufficiency, but in particular of a leakage-related trigger insufficiency. The trigger insufficiency shown is thus caused by leakages or by correction values, insufficiently determined by the programmable control unit 10, for taking account of leakage values such as mask leakages or technical leakages and can be reduced or avoided independently by the programmable control unit 10 by appropriate countermeasures.

[0091] It can be seen in FIG. 4 that, within the expiration phase T.sub.E of the respiratory air flow curve, during the increase in the respiratory air flow between the time points t.sub.3 and t.sub.4, a respiratory air flow increase, identified as a bulge, occurs as characteristic feature M.sub.1. In the respiratory air pressure curve, a respiratory air pressure increase, identified as a peak, can be seen as a further characteristic feature M.sub.3 between the time points t.sub.3 and t.sub.4, close in time to t.sub.4. The features M.sub.1 and M.sub.3 can already individually represent characteristic features of a frustrated breathing movement. However, they can also form a common characteristic feature of a frustrated breathing movement and can be evaluated coherently or in relation to each other. For example, it can be specified in the programmable control unit 10 that, in the sense of a two-factor dependency, the presence of a frustrated breathing movement is inferred only when the characteristic features M.sub.1 and M.sub.3 occur together.

[0092] It has been found that the characteristic features M.sub.1 and M.sub.3 are not only characteristic of a frustrated breathing movement in general, but in particular of a frustrated breathing movement as a result of an intrinsic PEEP of the living being 3. If the programmable control unit 10 detects a respiratory air flow increase, present as a bulge, in the respiratory air flow curve and also a respiratory air pressure increase that occurs simultaneously or during a second half of the respiratory air flow increase and is shaped as a peak, wherein the respiratory air pressure increase preferably has a smaller integral over the time of the increase than the respiratory air flow increase, the control unit 10 infers the presence of a frustrated breathing movement as a result of an intrinsic PEEP.

[0093] It can be seen in FIG. 5 that, within the expiration phase T.sub.E of the respiratory air flow curve, during the increase in the respiratory air flow between the time points t.sub.3 and t.sub.4, a respiratory air flow increase, identified as a bulge, occurs as characteristic feature M.sub.1. In the respiratory air pressure curve, a respiratory air pressure reduction, identified as a peak, can be seen in the first half of the time span between the time points t.sub.3 and t.sub.4, and a respiratory air pressure increase, identified as a peak, occurs as common characteristic feature M.sub.4 in the second half of the time span between time points t.sub.3 and t.sub.4. The features M.sub.1 and M.sub.4 can already individually represent characteristic features of a frustrated breathing movement. However, they can also form a common characteristic feature of a frustrated breathing movement and can be evaluated coherently or in relation to each other. For example, it can be specified in the programmable control unit 10 that, in the sense of a two-factor dependency, the presence of a frustrated breathing movement is inferred only when the characteristic features M.sub.1 and M.sub.4 occur together.

[0094] It has been found that the characteristic features M.sub.1 and M.sub.4 are not only characteristic of a frustrated breathing movement in general, but in particular of a frustrated breathing movement as a result of a trigger insufficiency. If the programmable control unit 10 detects a respiratory air flow increase, present as a bulge, in the respiratory air flow curve and also, during the first half of the time span between the time points t.sub.3 and t.sub.4, a respiratory air pressure reduction, identified as a peak, and, in the second half of the time span between the time point t.sub.3 and t.sub.4, a respiratory air pressure increase, identified as a peak, wherein the respiratory air pressure increases preferably each have a smaller integral over the time of the increase than the respiratory air flow increase, the control unit 10 infers the presence of a frustrated breathing movement as a result of a trigger insufficiency.

[0095] It has also been found that the characteristic features M.sub.1 and M.sub.4 are characteristic not only of a trigger insufficiency, but in particular of a parameter-related trigger insufficiency. Thus, the trigger insufficiency shown is caused by the programmable control unit 10 predefining parameter values for sensitivity settings of the inspiration and/or expiration trigger and can be reduced or avoided, through appropriate countermeasures, independently by the control unit 10 or by external correction inputs.

[0096] FIGS. 6 to 8 show, by way of examples, respiratory air pressure curves over time during a breathing cycle with an activated deflation function of the device 1. In this case, in the expiration phase T.sub.E of the breathing cycle, the device 1 generates a counterpressure which provides the living being 3 with breathing resistance and thereby enables more comfortable exhalation and prevents collapse of the airways. The breathing cycle begins at the time point t.sub.0 with an increase in the respiratory air pressure to the IPAP value p.sub.I. At the time point t.sub.1 the inspiration ends, and the expiration begins that ends at the time point t.sub.2. Between the time points t.sub.1 and t.sub.2, i.e. during the expiration, the device 1 generates a counterpressure.

[0097] The counterpressure is controlled, in particular dynamically, from a counterpressure start time t.sub.GA to a counterpressure end time t.sub.GE. A maximum counterpressure, the counterpressure amplitude p.sub.G, is reached between the time points t.sub.GA and t.sub.GE.

[0098] In FIG. 6, this counterpressure is already generated with the start of the expiration at the time point t.sub.1, that is to say without a counterpressure wait time after the time point t.sub.1. In FIGS. 7 and 8, initiation of the counterpressure generation is delayed, so that there is a time difference between the time point t.sub.1 and the time point t.sub.GA. This time difference is designated as the counterpressure wait time T.sub.GW. In FIG. 8, the counterpressure wait time T.sub.GW is set longer than in FIG. 7. In addition, the levels of the IPAP values p.sub.I and the counterpressure amplitudes p.sub.G in FIGS. 6 to 8 are chosen to be different. The counterpressure parameters of the counterpressure generated by the device 1 are thus variably adjustable, predefined by the programmable control unit 10 and/or dynamically adaptable to the respiratory air flow of the living being 3. The counterpressure parameters include, in particular, the counterpressure wait time T.sub.GW, the counterpressure amplitude p.sub.G, and counterpressure rise and fall times. The counterpressure wait time T.sub.GW is the time span between the time point of the change from an inspiration phase to an expiration phase and the start of the counterpressure build-up generated by the device 1. The counterpressure amplitude p.sub.G describes the maximum pressure value of the counterpressure above the pressure value that prevails at the time point t.sub.1+T.sub.GW at which no counterpressure is yet generated by the device 1. The counterpressure amplitude p.sub.G is preferably chosen as a function of the counterpressure wait time T.sub.GW. Furthermore, the counterpressure wait time T.sub.GW is preferably chosen as a function of the level of the IPAP value p.sub.I. The counterpressure curve over time can vary in order to meet the individual needs of the living being 3 for breathing resistance. Thus, for example, the counterpressure curve in FIG. 8 has a less steep counterpressure fall time compared to the counterpressure curve in FIG. 6 or 7. The counterpressure parameters are preferably automatically regulated by the programmable control unit 10 in such a way that the occurrence of frustrated breathing movements is avoided or at least reduced, by the control unit 10 varying the counterpressure parameters in a suitable manner when frustrated breathing movements are detected on the basis of characteristic features.

[0099] FIG. 9 shows a respiratory air pressure curve and respiratory air flow curve, actually recorded on the basis of measured values of a living being 3, with detectable frustrated breathing movements. The upper diagram shows the respiratory air pressure curve, and the lower diagram shows the respiratory air flow curve. It will be seen that, in the respiratory air flow curve, respiratory air flow increases, which are present as bulges, repeatedly occur in the expiration phase of the living being 3. By way of example, the temporal beginning and the temporal end of the respiratory air flow increase in a breathing cycle are indicated by the arrows A and B. In the respiratory air pressure curve, respiratory air pressure increases, identified as peaks, are repeatedly detected, the peaks of the respiratory air pressure increases being clearly smaller than the respiratory air flow increases that are identified as bulges. In addition, the respiratory air pressure increases occur temporally at the end of the respiratory air flow increases that are present as bulges, as can be seen for the breathing cycle selected as an example and indicated by the arrow C, which characterizes the occurrence of the respiratory air pressure increase. On the basis of the temporal relationship of the respiratory air flow increases and of the respiratory air pressure increases to each other, and on the basis of the forms of the respective increase, it is possible in the case of FIG. 9 to infer the presence of a frustrated breathing movement on account of an intrinsic PEEP.