DEVICE FOR VENTILATION WITH REGULATED PRESSURE TRANSITION

Abstract

A ventilation device comprising a controllable respiratory gas source and a programmable control unit being configured to perform the following: determining the respiratory gas flow, which is used to determine whether an inspiration or an expiration is present, regulating the pressure for an inspiration (IPAP) and an expiration (EPAP), wherein the control unit determines a typical expiration time over n breaths, the control unit lowers the pressure from the IPAP to the EPAP taking into account the typical expiration time in such a way that the pressure drop to the EPAP is already reached to the extent of at least 85% after a proportion of the typical expiration time in the range of 40-60% of the typical expiration time, the EPAP after completion of the pressure drop being predefined until the end of the typical expiration time.

Claims

1. A ventilation device, wherein the device comprises a controllable respiratory gas source and a programmable control unit, the programmable control unit being configured to: determine a respiratory gas flow, the respiratory gas flow being used to determine whether an inspiration or an expiration is present, regulate a pressure for an inspiration (IPAP) and an expiration (EPAP), wherein the control unit takes into account a typical expiration time, the control unit lowers the pressure from the IPAP to the EPAP taking into account a typical expiration time in such a way that a pressure drop to the EPAP is already reached to an extent of at least 85% after a proportion of the typical expiration time in a range of 40-60% of the typical expiration time, the EPAP after completion of the pressure drop being predefined until an end of the typical expiration time.

2. The device of claim 1, wherein the control unit determines a typical expiration time over n breaths and takes into account the expiration time thus determined, or the control unit takes into account a fixedly predefined expiration time, which is predefined either explicitly or implicitly via a specification of an inspiration time and of a respiratory frequency.

3. The device of claim 1, wherein the pressure is lowered from the IPAP to the EPAP in the form of an adaptive pressure ramp, the pressure reaching the EPAP after 40-60% of the typical expiration time.

4. The device of claim 1, wherein the EPAP is reached after a proportion of the typical expiration time, which is 50%.

5. The device of claim 1, wherein, after detection of an exhalation phase, the pressure is lowered from the IPAP to the EPAP such that the pressure is applied as a dynamically regulated counterpressure against the respiratory gas flow of the expiration, as a result of which lower airways in COPD patients with expiratory flow limitation remain supported for approximately half of the typical expiration time and do not collapse.

6. The device of claim 1, wherein the pressure is reduced from the IPAP to the EPAP as a non-linear drop with asymptotic approximation to the EPAP.

7. The device of claim 1, wherein the pressure is reduced from the IPAP to the EPAP such that 90% of the pressure drop is reached after approximately half of the expiration time.

8. The device of claim 1, wherein the pressure is regulated only at a start of the expiration and, after the EPAP is reached, is left at this level.

9. The device of claim 1, wherein the control unit is configured and designed to detect an increase of an expiratory resistance and to perform the pressure drop from the IPAP to the EPAP taking into account the expiratory resistance.

10. The device of claim 1, wherein the control unit is configured and designed to detect an increased residual flow at an end of the expiration and to perform the pressure drop from the IPAP to the EPAP taking into account the increased residual flow at the end of the expiration.

11. The device of claim 1, wherein the control unit is configured and designed to vary a steepness of the pressure drop and to determine at which steepness of the pressure drop a best emptying of air from lungs takes place.

12. The device of claim 1, wherein the control unit is configured and designed to change a steepness of the pressure drop according to a specification that is input via a data interface.

13. The device of claim 1, wherein the control unit is configured and designed to control a change in a steepness of the pressure drop on the basis of sensor signals.

14. The device of claim 1, wherein the control unit is configured and designed to change a steepness of the pressure drop when a pressure assistance is adapted, i.e., a difference between IPAP and EPAP is changed.

15. The device of claim 1, wherein the control unit is configured and designed to change a steepness of the pressure drop when the EPAP is adapted.

16. The device of claim 1, wherein the control unit determines a typical inspiration time over n breaths, and the control unit raises the pressure from the EPAP to the IPAP taking into account the characteristic inspiration time, such that the IPAP is reached after a proportion of the typical inspiration time in a range of 20-40%.

17. The device of claim 1, wherein the control unit lowers the pressure from the EPAP to the IPAP taking into account a typical inspiration time in such a way that the IPAP is reached after a proportion of the typical inspiration time in a region of 30%.

18. The device of claim 1, wherein the control unit raises the pressure from the EPAP to the IPAP in such a way that a result is a non-linear rise with asymptotic approximation to the IPAP.

19. The device of claim 1, wherein the control unit raises the pressure from the EPAP to the IPAP in such a way that approximately 90% of a rise is reached after 30% of the inspiration time.

20. The device of claim 1, wherein the pressure change (EPAP to IPAP or IPAP to EPAP) can be specified with a fixed duration or speed or step associated therewith.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Further advantages and features of the present invention will become clear from the description of the illustrative embodiments, which are explained below with reference to the accompanying drawings. In the drawings,

[0051] FIG. 1 shows a device according to the invention with a breathing mask as a patient interface;

[0052] FIG. 2A shows the respiratory gas flow that has been recorded by sensors of a device of the invention;

[0053] FIG. 2B shows how a device of the prior art predefines the IPAP and the EPAP in the alternation of inspiration and expiration; and

[0054] FIG. 2C shows how a device of the invention predefines the IPAP and the EPAP in the alternation of inspiration and expiration;

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

[0055] The particulars shown herein are by way of example and for purposes of illustrative discussion of the embodiments of the present invention only and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the 5 present invention. In this regard, no attempt is made to show details of the present invention in more detail than is necessary for the fundamental understanding of the present invention, the description in combination with the drawings making apparent to those of skill in the art how the several forms of the present invention may be embodied in practice.

[0056] FIG. 1 shows the device 20 according to the invention with a breathing mask 41 as a patient interface. The mask is fastened on the head with straps 42. The mask can be connected to the hose via a connector 43.

[0057] The device 20 comprises a respiratory gas source 21, a control unit 22, a reservoir 25, a pressure sensor device 24 and/or a flow sensor device 23, a respiratory gas hose 31 and a patient interface, which is here designed as a breathing mask 41. The device additionally has an operating unit 26 and a display 27. The device has at least one connector 28 for the respiratory gas hose 31. A connector 28 is configured for the attachment of the one respiratory gas hose 31 in the form of a single-hose valve system 31. A leakage hose can also be attached to this connector.

[0058] Moreover, the inspiratory branch of a double-hose system can be attached to this connector 28. The other connector 28′ serves for the attachment of the expiratory branch of the double-hose system.

[0059] The device can be used with a leakage hose, a single-hose valve system or a double-hose system. In the leakage hose, the CO2-containing exhaled air is continuously flushed out via an exhalation system. In the single-hose valve system and in the double-hose system, the exhalation by the patient is controlled via a valve 30.

[0060] In the double-hose system, the valve 30 is arranged in the device. The exhaled air is conveyed via a subsidiary hose to the expiratory input connector 28′ and from there is discharged via the valve 30 into the atmosphere. The valve for this purpose opens with each expiration. The valve is closed with each inspiration.

[0061] A pressure measurement hose 32 registers the pressure in the hose system. The control pressure for the valve 30 comes from the device via a pressure hose 35.

[0062] In the single-hose valve system, the valve 30 is arranged in or on the hose 31.

[0063] FIG. 2A shows the respiratory gas flow 33 that has been recorded by sensors 23 of the device 20. The inspiration 1 by the patient and the expiration 2 by the patient are seen from the flow signal 33. Inspiration and expiration alternate with each other in the breathing rhythm of the patient. From the flow 33, the control unit can detect the change between inspiration and expiration and can accordingly alter the pressure specification 34. From the flow, the control unit can detect the change between inspiration and expiration and determine the durations of inspiration (Ti) and expiration (Te).

[0064] FIG. 2B and FIG. 2C show that the device predefines the IPAP 5 and the EPAP 6 in the alternation of inspiration and expiration.

[0065] It will be seen from FIG. 2B that, in devices according to the prior art, the change from the IPAP to the EPAP takes place for the most part over a ramp-shaped pressure drop 7. The EPAP is reached shortly after the change of respiration phase. The change from the EPAP to the IPAP also takes place for the most part over a ramp-shaped pressure rise 8. The IPAP is then also reached quickly. The ramps 7, 8 can each typically be set or predefined with a fixed duration or speed.

[0066] FIG. 2C shows the innovation according to the invention. The device 20 controls 22 the pressure drop from the IPAP 5 to the EPAP 6, such that the EPAP is reached after half of the typical expiration time 3, or 90% of the pressure drop is reached after half of the typical expiration time 3. For this purpose, the ventilation device 20 has a controllable respiratory gas source (21) and a programmable control unit (22).

[0067] The programmable control unit (22) is configured to perform the following steps: [0068] determining the respiratory gas flow (33), the respiratory gas flow (33) being used to determine whether an inspiration or an expiration is provided, [0069] regulating the pressure for an inspiration (IPAP) and an expiration (EPAP), wherein [0070] the control unit (22) determines a typical expiration time 3 over n breaths, [0071] the control unit (22) lowers the pressure from the IPAP (5) to the EPAP (6) taking into account the typical expiration time (3), in such a way that the pressure drop to the EPAP (6) is already reached to the extent of least about 90% after a proportion or fraction of the typical expiration time (3).

[0072] In the example of the adaptive pressure ramp 9, the pressure reaches the EPAP after about 40-60%, preferably after about 50%, of the typical expiration time 3.

[0073] In the example of the non-linear drop 11 with asymptotic approximation to the EPAP, the drop to the EPAP reaches at least about 80%, preferably about 90%, after 40-60%, preferably after about 50%, of the typical expiration time 3.

[0074] The shift is effected, for example, by the control unit determining the mean expiration time 3 using a weighted average filter, which takes account of about the last 10 breaths. The pressure is lowered from IPAP to EPAP at a suitable speed, such that the EPAP is reached after about 50% of the average expiration time. There is therefore still enough time for the non-collapsed areas of the lungs to empty of air to the EPAP level. The collapsible areas remain opened at least during part of the ramp time and are thus partially emptied of air.

[0075] The setpoint expiration times or inspiration times, to which the % target values of the EPAP/IPAP attainment and thus the ramp gradients relate, can be derived from the spontaneous breathing pattern of the patient.

[0076] The setpoint expiration times or inspiration times, to which the % target values of the EPAP/IPAP attainment and thus the ramp gradients relate, can alternatively or additionally also be predefined as ideal inspiration or expiration times.

[0077] The specification can be made manually or performed automatically on the basis of at least one of the parameters: age, size, disease, therapy goal, lung volume, lung compliance, lung resistance, respiratory effort, shortness of breath.

[0078] FIG. 2C also shows the innovation according to the invention for the pressure rise. The device 20 controls 22 the pressure rise to the IPAP 5, such that the IPAP is reached after 20-40%, preferably after 30%, of the typical inspiration time.

[0079] In the example of the adaptive pressure ramp, the pressure reaches the IPAP after 30% of the typical inspiration time.

[0080] The shift is effected, for example, by the control unit determining the typical inspiration time 4 using a weighted average filter, which takes account of about the last 10 breaths. The pressure is raised from EPAP to IPAP at a suitable speed, such that the IPAP is reached after about 30% of the typical inspiration time.

[0081] In the example of the non-linear rise 12 with asymptotic approximation to the IPAP, the rise at least preferably to the extent of about 90% after 40-60%, preferably after 50%, of the typical expiration time.

[0082] In the example of the non-linear drop 11 with asymptotic approximation to the EPAP, the drop to the EPAP reaches at least about 80%, preferably about 90%, after about 20-40%, preferably after about 30%, of the typical inspiration time. FIG. 2C shows [0083] 1 inspiration by the patient [0084] 2 expiration by the patient [0085] 3 50% of the typical expiration time (Te) [0086] 4 30% of the typical inspiration time (Ti) [0087] 5 IPAP level (inspiratory pressure) [0088] 6 EPAP level (expiratory pressure) [0089] 7 pressure ramp IPAP>EPAP, typically with fixed duration or speed or step associated therewith [0090] 8 pressure ramp EPAP>IPAP, typically with fixed duration or speed or step associated therewith [0091] 9 adaptive pressure ramp, reaches the EPAP after about 50% of the typical expiration time [0092] 10 adaptive pressure ramp, reaches the IPAP after about 30% of the typical inspiration time [0093] 11 alternative embodiment of the ramp; no linear drop, instead a non-linear drop with asymptotic approximation to the EPAP; characteristic value: e.g. about 90% of the drop reached after about 50% of the expiration time [0094] 12 alternative embodiment of the ramp; no linear rise, instead a non-linear rise with asymptotic approximation to the IPAP; characteristic value: e.g. about 90% of the rise reached after about 30% of the inspiration time

[0095] According to the invention, the control of the expiration ramp is as flat as possible, so that the lower airways in COPD patients with expiratory flow limitation remain supported for as long as possible and do not collapse. In this way, air is better removed from the lungs and there is a lower intrinsic PEEP. The patient can breathe more easily, since the lungs remain less distended, and can release the trigger. After the ventilator has been switched off, breathing is found to be easier.

[0096] The shift is effected, for example, by the mean expiration time being determined by a weighted average filter, which takes account of ca. the last 10 breaths. The pressure is lowered from IPAP to EPAP at a suitable speed, such that the EPAP is reached after about 50% of the average expiration time. There is therefore still enough time for the non-collapsed areas of the lungs to empty of air to the EPAP level. The collapsible areas remain opened at least during part of the ramp time and are thus partially emptied of air.

[0097] To sum up, the present invention provides: [0098] 1. A ventilation device which comprises a controllable respiratory gas source and a programmable control unit, the programmable control unit being configured to: [0099] determine a respiratory gas flow, the respiratory gas flow being used to determine whether an inspiration or an expiration is present, [0100] regulate a pressure for an inspiration (IPAP) and an expiration (EPAP), wherein [0101] the control unit takes into account a typical expiration time, [0102] the control unit lowering the pressure from the IPAP to the EPAP taking into account a typical expiration time in such a way that a pressure drop to the EPAP is already reached to an extent of at least 85% after a proportion of the typical expiration time in a range of 40-60% of the typical expiration time, the EPAP after completion of the pressure drop being predefined until an end of the typical expiration time. [0103] 2. The device of item 1, wherein the control unit determines a typical expiration time over n breaths and takes into account the expiration time thus determined, or the control unit takes into account a fixedly predefined expiration time, which is predefined either explicitly or implicitly via the specification of an inspiration time and of a respiratory frequency. [0104] 3. The device of at least one of the preceding items, wherein the pressure is lowered from the IPAP to the EPAP in the form of an adaptive pressure ramp, the pressure reaching the EPAP after 40-60%, preferably after 50%, of the typical expiration time. [0105] 4. The device of at least one of the preceding items, wherein the EPAP is reached after a proportion of the typical expiration time, which is 50%. [0106] 5. The device of at least one of the preceding items, wherein, after detection of an exhalation phase, the pressure is lowered from the IPAP to the EPAP such that the pressure is applied as a dynamically regulated counterpressure against the respiratory gas flow of the expiration, as a result of which the lower airways in COPD patients with expiratory flow limitation remain supported for approximately half of the typical expiration time and do not collapse. [0107] 6. The device of at least one of the preceding items, wherein the pressure is reduced from the IPAP to the EPAP as a non-linear drop with asymptotic approximation to the EPAP. [0108] 7. The device of at least one of the preceding items, wherein the pressure is reduced from the IPAP to the EPAP such that 90% of the pressure drop is reached after approximately half of the expiration time. [0109] 8. The device of at least one of the preceding items, wherein the pressure is regulated only at the start of the expiration and, after the EPAP is reached, is left at this level. [0110] 9. The device of at least one of the preceding items, wherein the control unit is configured and designed to detect an increase of the expiratory resistance and to perform the pressure drop from the IPAP to the EPAP taking into account the expiratory resistance, for example by means of the ramp of the pressure drop being set flatter. [0111] 10. The device of at least one of the preceding items, wherein the control unit is configured and designed to detect an increased residual flow at the end of the expiration and to perform the pressure drop from the IPAP to the EPAP taking into account the increased residual flow at the end of the expiration, for example by means of the ramp of the pressure drop being set steeper. [0112] 11. The device of at least one of the preceding items, wherein the control unit is configured and designed to vary the steepness of the pressure drop, for example from breath to breath, and to determine at which steepness of the pressure drop the best emptying of air from the lungs takes place. [0113] 12. The device of at least one of the preceding items, wherein the control unit is configured and designed to change a steepness of the pressure drop, for example based on how great the percentage of the expiration time the EPAP is intended to reach, according to the specification that is input via a data interface. [0114] 13. The device of at least one of the preceding items, wherein the control unit is configured and designed to control a change in the steepness of the pressure drop on the basis of sensor signals, for example from effort belts, diaphragm EMG, esophageal pressure probes, body plethysmography or electrical impedance tomography. [0115] 14. The device of at least one of the preceding items, wherein the control unit is configured and designed to change the steepness of the pressure drop when the pressure assistance is adapted, i.e., the difference between IPAP and EPAP is changed. [0116] 15. The device of at least one of the preceding items, wherein the control unit is configured and designed to change the steepness of the pressure drop when the EPAP is adapted. [0117] 16. The device of at least one of the preceding items, wherein [0118] the control unit determines a typical inspiration time over n breaths, [0119] the control unit raises the pressure from the EPAP to the IPAP taking into account the characteristic inspiration time, such that the IPAP is reached after a proportion of the typical inspiration time in a range of 20-40%. [0120] 17. The device of at least one of the preceding items, wherein the control unit lowers the pressure from the EPAP to the IPAP taking into account the typical inspiration time, in such a way that the IPAP is reached after a proportion of the typical inspiration time in a region of 30%. [0121] 18. The device of at least one of the preceding items, wherein the control unit raises the pressure from the EPAP to the IPAP in such a way that the result is a non-linear rise with asymptotic approximation to the IPAP. [0122] 19. The device of at least one of the preceding items, wherein the control unit raises the pressure from the EPAP to the IPAP in such a way that approximately 90% of the rise is reached after 30% of the inspiration time. [0123] 20. The device of at least one of the preceding items, wherein the pressure change (EPAP to IPAP or IPAP to EPAP) can be specified with a fixed duration or speed or step associated therewith. [0124] 21. The device of at least one of the preceding items, wherein the control unit determines the typical expiration time and/or typical inspiration time over at least three breaths or preferably 10 breaths, wherein a breath comprises an inspiration and an expiration. [0125] 22. The device of at least one of the preceding items, wherein a respiratory volume of the inspiration (AI) is determined, and the duration of the expiration is adapted when the respiratory volume of the expiration (AE) reaches the value of the respiratory volume of the inspiration (AI).