CUSHION ELEMENT FOR A PATIENT INTERFACE

Abstract

The present invention relates to a cushion element (14) for a patient interface (10) for providing a flow of breathable gas to a patient (12), wherein the cushion element (14) comprises a face-contacting layer (32) for contacting a face of the patient (12) during use of the cushion element (14) and a responsive layer (34) which is covered by the face-contacting layer (32). The responsive layer (34) comprises a plurality of active and passive zones (38, 40) that are arranged alternately side by side to one another. Each of the active zones (38) comprises at least one actuator (42) for moving the face-contacting layer (32), and wherein each of the passive zones (40) comprises a cushion material that is arranged between the actuators (42). The face-contacting layer (32) forms a corrugated or undulating surface (46) covering both the active and the passive zones (38, 40), wherein first parts (48) of said surface (46) covering the active zones (38) project beyond or are recessed relative to second parts (50) of said surface (46) covering the passive zones (40).

Claims

1. A cushion element for a patient interface for providing a flow of breathable gas to a patient, wherein the cushion element comprises: a face-contacting layer for contacting a face of the patient during use of the cushion element; and a responsive layer which is covered by the face-contacting layer; wherein the responsive layer comprises a plurality of active and passive zones that are arranged alternately side by side to one another, wherein each of the active zones comprises at least one actuator for moving the face-contacting layer, and wherein each of the passive zones comprises a cushion material that is arranged between the actuators, wherein the face-contacting layer forms a corrugated or undulating surface covering both the active and the passive zones, wherein first parts of said surface covering the active zones project beyond or are recessed relative to second parts of said surface covering the passive zones.

2. The cushion element according to claim 1, wherein the actuators are configured to move the first parts of said surface relative to the second parts of said surface by expanding the active zones in a first direction towards the face of the patient and/or by contracting the active zones in a direction opposite the first direction.

3. The cushion element according to claim 2, wherein the active zones are configured to communicate with the passive zones via the cushion material that is integrated in the responsive layer, such that an expansion of the active zones causes a contraction of the passive zones, and a contraction of the active zones causes an expansion of the passive zones.

4. The cushion element according to claim 1, wherein the active and passive zones are arranged in columns next to one another, wherein columns forming the active zones and columns forming the passive zones are arranged alternately side by side to one another.

5. The cushion element according to claim 2, wherein the columns forming the active zones and the columns forming the passive zones are arranged parallel to the first direction.

6. The cushion element according to claim 1, further comprising a support layer for providing mechanical stability to the responsive layer, wherein the support layer is arranged on a first side of the responsive layer, and wherein the face-contacting layer is arranged on a second side opposite the first side of the responsive layer.

7. The cushion element according to claim 1, wherein the at least one actuator of each active zone comprises an electroactive polymer and an electrode for activating the electroactive polymer.

8. The cushion element according to claim 1, wherein each of the active zones comprises a plurality of actuators.

9. The cushion element according to claim 2, wherein each of the plurality of actuators comprises an electroactive polymer and an electrode that is arranged transverse to the first direction.

10. The cushion element according to claim 2, wherein each of the active zones has a width (w) of 100 mw100 mm, said width (w) being measured in a second direction transverse to the first direction.

11. The cushion element according to claim 1, wherein the plurality of active zones are arranged in concentric closed loops.

12. The cushion element according to claim 1, wherein the cushion element is one of a nose cushion, a mouth cushion and a forehead cushion.

13. A patient interface for providing a flow of breathable gas to a patient, wherein the patient interface comprises a cushion element according to claim 1.

14. The patient interface according to claim 13, further comprising a voltage source which is connected to the at least one actuator of each active zone.

15. A pressure support system, comprising: a pressure generator for generating a flow of breathable gas; and a patient interface for providing the flow of breathable gas to a patient, wherein the patient interface comprises a cushion element according to claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0045] These and other aspects of the invention will be apparent from and elucidated with reference to the embodiment described hereinafter. In the following drawings

[0046] FIG. 1 shows an exemplary embodiment of a patient interface in which a cushion element according to the present invention may be applied;

[0047] FIG. 2 shows a backside of the patient interface shown in FIG. 1; and

[0048] FIG. 3 shows a schematic cross section of an embodiment of the cushion element according to the present invention, wherein FIG. 3A shows the cushion element in a first operating state and FIG. 3B shows the cushion element in a second operating state.

DETAILED DESCRIPTION OF THE INVENTION

[0049] FIG. 1 shows an exemplary embodiment of a patient interface for delivering a flow of breathable gas to a patient. The patient interface is therein in its entirety denoted by reference numeral 10.

[0050] In this embodiment the patient interface 10 is designed as a full-face mask covering the mouth and the nose of a patient 12. It shall be noted that the patient interface 10 may alternatively be designed as a nose mask, a mouth mask or as a total face mask without leaving the scope of the present invention.

[0051] The patient interface 10 comprises a cushion element 14 and a mask shell 16. The cushion element 14 is designed to contact the face of the patient 12 and to provide an airtight seal at the interface between the patient's face and the patient interface 10. The cushion element 14 usually comprises a soft material, like silicon or any other rubber or suitable elastic material. The mask shell 16 provides a flexible, semi-rigid or rigid support structure for holding the cushion element 14. The mask shell 16 is usually connected to the backside of the cushion element 14, wherein the backside is meant to denote the side of the cushion element 14 opposite to the side of the cushion element 14 contacting the patient's face during use. The mask shell 16 may either be releasably or fixedly connected to the cushion element 14. The cushion element 14 and the mask shell 16 thus together form a cavity which is in this case designed to receive the mouth and the nose of the patient 12. It shall be noted that the cushion element 14 and the mask shell 16 may alternatively be formed as one integral piece.

[0052] On the opposite side directing away from the patient's face, the mask shell 16 preferably comprises a connector 18. Via this connector 18 the patient interface 10 may be connected to a hose (not shown) via which a pressurized flow of breathable gas can be submitted to the patient interface 10. The mask shell 16 is further connected to a headgear 20. This headgear 20 is used for attaching the patient interface 10 to the patient's head. According to the exemplary embodiment shown in FIG. 1, the headgear 20 comprises a rigid frame 22 and lower and upper headgear straps 24, 26. These lower and upper headgear straps 24, 26 may be connected to the frame 22 of the headgear 20 and used for donning the mask shell 16 and the cushion element 14 to the patient's face.

[0053] In the illustrated example the headgear 20 furthermore comprises a forehead support 28. This forehead support 28 allows stabilizing the patient interface 10 while being donned to the patient's face. The forehead support 28 reduces the pressure that is exerted onto the patient's nose during use. In order to make the forehead support 28 as comfortable as possible, the forehead support 28 furthermore comprises a forehead cushion 30 which is attached thereto. This forehead cushion 30 is according to the present invention also considered as a cushion element (similar as cushion element 14).

[0054] FIG. 2 shows a schematic view of the patient interface 10, the cushion element 14 and the forehead support 28 from the other side, i.e. from the side with which the cushion element 14 and the forehead cushion 30 contact the patient's face.

[0055] FIGS. 3A and 3B show a schematic cross section of the cushion element 14 according to an embodiment of the present invention. The multi-layer structure of the cushion element 14 is therein illustrated in detail.

[0056] In the illustrated example the cushion element 14 basically comprises three layers: a face-contacting layer 32, a responsive layer 34 and a support layer 36. The face-contacting layer 32 forms the top surface of the cushion element 14 that contacts the patient's face during use. It may be made of a thin elastomeric film and has the function to provide a skin-friendly interface. The support layer 36 is arranged at the backside of the cushion element 14 that is usually connected to the mask shell 16. This support layer 36 is preferably made of a rubber material that is stiffer and less resilient than the materials from which the face-contacting layer 32 and the responsive layer 34 are made. The support layer 36 shall provide mechanical stability. However, it shall be noted that this support layer 36 is not necessarily needed if the function of providing mechanical stability is fulfilled by the mask shell 16 itself. The responsive layer 34 would in this case be sandwiched between the face-contacting layer 32 and the mask shell 16 instead of being sandwiched between the face-contacting layer 32 and the support layer 36 as shown in FIG. 3. Both alternatives are possible.

[0057] One of the central features of the presented cushion element 14 is the structure of the responsive layer 34. The responsive layer 34 is split up into active zones/areas 38 and passive zones/areas 40. Zones 38 are called active zones since these zones of the responsive layer 34 are configured to actively move the face-contacting layer 32. Zones 40 are denoted as passive zones since these zones are not actively moved (actuated), but move indirectly as soon as the active zones 38 are moved. This will become more apparent from the explanations given below.

[0058] As it can be seen in FIGS. 3A and 3B, the active zones 38 and the passive zones 40 are arranged alternately side by side to one another. The active and passive zones 38, 40 are in the shown example arranged in parallel columns next to one another. Each active zone 38 comprises a plurality of actuators 42. These actuators 42 are configured to move the face-contacting layer 32 by expanding the active zones 38 in a first direction 44 towards the patient's face and/or by contracting the active zones 38 in a direction opposite the first direction 44. The actuators 42 are preferably configured to periodically expand and contract the active zones 38 of the responsive layer 34. In order to realize this movement the use of electrically actuated actuators 42 is preferred. Such actuators 42 may, for example, be controlled in such a way that the active zones 38 are contracted when the actuators 42 are activated, whereas the active zones 38 are expanded again when the actuators 42 are deactivated. However, it is also possible to control such actuators 42 the other way around, such that, they expand the active zones 38 when being activated and contract the active zones 38 again when being deactivated. A preferred embodiment for such actuators 42 will be explained further below.

[0059] A further central feature of the cushion element 14 according to the present invention is the technical design and structure of the face-contacting layer 32. In contrast to most cushion elements 14 according to the prior art, this face-contacting layer 32 is not formed as an even, flat surface, but rather formed as an uneven, corrugated or undulating surface 46 (see FIGS. 3A and 3B). This surface 46 comprises several interconnected segments which are herein denoted as first parts 48 and second parts 50 of the surface 46. The first parts 48 are the parts of the corrugated or undulating surface 46 that cover the active zones 38. The second parts 50 are the parts of the surface 46 that cover the passive zones 40. The first and second parts 48, 50 are therefore also arranged alternately side by side to one another. Depending on the activation state of the actuators 42, the first parts 48 of the surface 46 either project beyond or are recessed relative to the second parts 50 of the surface 46. In the exemplary embodiment shown in FIG. 3, FIG. 3A shows the deactivated state of the actuators 42 and FIG. 3B shows the activated state of the actuators 42. In this example, the first parts 48 thus project beyond the second parts 50 in the deactivated state (see FIG. 3A), whereas the first parts 48 are recessed relative to the second parts 50 in the activated state of the actuators 42 (see FIG. 3B). It is clear that the technical design may be chosen to be just the way around.

[0060] Due to the above-mentioned structure of the cushion element 14, the face-contacting layer 32 does not contact the patient's face along the whole surface 46 during use, but rather performs an undulating or wavelike movement. This prevents static pressure points which could otherwise lead to a formation of red marks within the patient's face.

[0061] In the preferred embodiment illustrated in FIGS. 3A and 3B the actuators 42 are designed as electroactive polymer (EAP) actuators. In this case each EAP actuator 42 comprises two opposing electrodes 52 and an electroactive polymer material 54 that is arranged in between the electrodes 52. The electroactive polymer material 54 may be either configured to contract or to expand as soon as a voltage is applied to the electrodes 52. In the shown example, the electroactive polymer material 54 is configured to contract as soon as a voltage is applied thereto

[0062] It can be furthermore seen from FIGS. 3A and 3B that each active zone 38 of the responsive layer 34 comprises a plurality of electrodes 52 and electroactive polymer layers 54 arranged in between them. The electrodes 52 are preferably arranged perpendicular to the first direction 44, i.e. parallel to the first parts 48 of the undulating surface 46.

[0063] FIG. 3B shows the activated state of the actuators 42, i.e. the state in which a voltage is applied to the electrodes 52. By comparing FIG. 3A with FIG. 3B it may be seen that the first parts 48 of the undulating surface 46 so to say change places with the second parts 50 of the undulating surface 46 as soon as a voltage is applied to the electrodes 52 of the actuators 42. This results from the following fact: The active zones 38 communicate with the passive zones 40 via the cushion material that is integrated in the responsive layer 34. An activation of the actuators 42 causes the active zones 38 to contract (see FIG. 3B). This contraction shifts the material, which is present in between the electrodes 52, from the active zones 38 into the passive zones 40. The second parts 50 of the undulating surface 46 will then bulge outwardly so that they then project beyond the first parts 48 of the undulating 46. A wavelike movement of the face-contacting layer 32 may thus be achieved by alternately activating and deactivating the actuators 42 in the active zones 38 of the responsive layer 34. During this movement the first parts 48 and the second parts 50 of surface 46 will be alternately in contact with the patient's face.

[0064] The actuators 42 of the above-mentioned exemplary embodiment may be easily driven by a voltage source (e.g. a battery) which is either integrated into the cushion element 14 itself or arranged at another position on the patient interface 10. This voltage source (not shown) is preferably connected to each of the actuators 42 via a voltage converter. A simple microprocessor may be used to steer the actuators 42 in the above-mentioned way.

[0065] The width w of the active and passive zones 38, 40 may be designed in a relatively free manner. Experiments of the applicant have shown that the best massaging effects may be achieved if the width w ranges between 100 m and 100 mm.

[0066] It shall be further noted that the above-mentioned structure of the cushion element 14 may not only be used in the main cushion 14 forming the airtight seal of the mask 10, but could alternatively or additionally also be used in the forehead cushion 30. The only difference is that in the sealing cushion 14 one also needs to take account for the sealing behavior such a cushion element should fulfill. It is therefore preferred that the active zones 38 and passive zones 40 of the responsive layer 34 are arranged in concentric closed loops (see FIG. 2).

[0067] While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive; the invention is not limited to the disclosed embodiments. Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims.

[0068] In the claims, the word comprising does not exclude other elements or steps, and the indefinite article a or an does not exclude a plurality. A single element or other unit may fulfill the functions of several items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

[0069] Any reference signs in the claims should not be construed as limiting the scope.