CPAP PRESSURIZED GAS PERMEABLE MASK CUSHION

Abstract

The present invention relates to a patient-contacting element (10) or a patient interface (12) including such a patient-contacting element (10) wherein the required minimum pressure for sealing may be realized for all different values of CPAP pressure. In particular, the present invention relates to a patient-contacting element (10) for a patient interface (12) for delivering a flow of gas to a user (20), said patient-contacting element (10) being configured to provide a substantially air-tight seal with the user's skin during use and comprises an inlet (14) for receiving at least part of the flow of gas (40), at least one gas-permeable element (16) that is disposed within the patient-contacting element (10) and arranged in fluidic communication with the inlet (14), and a first layer (18) of an air-tight material that is arranged between the at least one gas-permeable element (16) and an inner space (52) of the patient-contacting element (10) for receiving a nose and/or a mouth of the user (50), wherein the air-tight material has at least one opening (20) therein.

Claims

1. A patient-contacting element for a patient interface for delivering a flow of gas to a user, said patient-contacting element being configured to provide a substantially air-tight seal with the user's skin during use and comprises: an inlet for receiving at least part of the flow of gas, at least one gas-permeable element that is disposed within the patient-contacting element and arranged in fluidic communication with the inlet, a first layer of an air-tight material that is arranged between the at least one gas-permeable element and an inner space of the patient-contacting element for receiving a nose and/or a mouth of the user, wherein the air-tight material has at least one opening therein: and a second layer of an air-tight material that is arranged between the at least one gas-permeable element and an outer space of the patient-contacting element which is not in fluid communication with the flow of gas during use.

2. The patient-contacting element according to claim 1, comprising at least one further layer of an air-tight material covering at least a portion of the at least one gas-permeable element.

3. (canceled)

4. The patient-contacting element according to claim 1, wherein the inlet opens out directly into the at least one gas-permeable element in order to provide at least part of the flow of gas directly to the at least one gas-permeable element.

5. The patient-contacting element according to claim 1, wherein the patient-contacting element is a cushion.

6. The patient-contacting element according to claim 1, wherein the at least one gas-permeable element comprises a foam and/or a stack of spacer fabrics.

7. The patient-contacting element according to claim 6, wherein the foam is an open cell foam.

8. The patient-contacting element according to claim 1, wherein a shape of the at least one gas-permeable element is adapted to contour of a user's face or head.

9. The patient-contacting element according to claim 1, wherein properties of the at least one gas-permeable element vary along the at least one gas-permeable element.

10. The patient-contacting element according to claim 1, wherein the patient-contacting element comprises a plurality of gas permeable elements.

11. The patient-contacting element according to claim 1, comprising a third layer which covers at least a portion of the patient-contacting element and provides the substantially air-tight seal with the user's skin during use, wherein the third layer is not directly connected to the at least one gas-permeable element.

12. The patient-contacting element according to claim 11, wherein the third layer comprises a polymer film, a polymer membrane, a closed cell foam and/or a coated textile fabric.

13. The patient-contacting element according to claim 12, wherein the polymer film is a polyurethane film or silicone film.

14. (canceled)

15. The patient-contacting element according to claim 1, further comprising one or more of a forehead pad, a headgear and a cheek-mounted support.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0065] These and other aspects of the invention will be apparent from and elucidated with reference to the embodiment(s) described hereinafter. In the following figures examples are purely illustrative of specific embodiments should not be understood as limiting the scope of invention. In the following drawings

[0066] FIG. 1 shows an example of a patient interface according to the present invention.

[0067] FIGS. 2a and b schematically illustrate a first embodiment of the patient interface according to the present invention.

[0068] FIG. 3 schematically illustrates the position of a skin contacting element with respect to the user's skin and the flow of gas therein according to a first embodiment.

[0069] FIG. 4 schematically illustrates the position of a skin contacting element with respect to the user's skin and the flow of gas therein according to a second embodiment.

[0070] FIG. 5 schematically illustrates the position of a skin contacting element with respect to the user's skin and the flow of gas therein according to a third embodiment.

[0071] FIG. 6 schematically illustrates the position of a skin contacting element with respect to the user's skin and the flow of gas therein according to a fourth embodiment.

[0072] FIGS. 7a to 7c show the optimal compression ranges for constant cushion stiffness, non-constant cushion stiffness and air-assisted cushion stiffness, respectively.

DETAILED DESCRIPTION OF THE INVENTION

[0073] FIG. 1 shows an example of a mask according to the present invention. The main structural elements of the mask shown in FIG. 1 are generally known and not particularly designated. The embodiments according to the present invention are shown in FIGS. 3 to 7. However, FIG. 1 shall give an overview of the main structural elements comprised in a patient interface.

[0074] The patient interface is in FIG. 1 in its entirety denoted with reference numeral 12. The mask 12, in the following also referred to as patient interface 12, is typically used in pressure support systems (CPAP systems). That is to supply a flow of gas to the airway of a patient 50. Such patient interfaces are well known and are mostly worn on the head using a strap system around a patient's head to hold the mask 12 in place around the airway entry features of the human face. The patient interface 12 typically comprises a rigid or semi-rigid mask shell to which the headgear/strap system is attached. The mask shell is usually made of a rigid or semi-rigid material, such as e.g. plastic, polycarbonate or silicon. However, also other materials are generally conceivable. The mask shell serves as a holding frame for holding a flexible soft cushion/mask flap 10, also referred to as patient-contacting element.

[0075] The patient-contacting element 10 engages the patient's face wherein the mask/patient interface 12 is attached to the patient's face during use. It serves as mask to patient interface.

[0076] These patient-contacting elements 10 or cushions 10 are made in the art out of silicon and comprise one or more gel pads in order to establish a soft contact on the patient's face. A further function of these cushions 10 is the sealing of the interior of the patient's interface 12 to the exterior surrounding in order to prevent air leaks between the patient's interface 12 and the patient's face when pressure is applied to the patient's airway. The shape of the cushion/mask flap 10 is thereto preferably adapted to the shape of the user's face. The patient-contacting element 10 may not only be embodied as cushion, but may be also in form of a forehead pad 24, a headgear and a cheek-mounted support.

[0077] The example illustrated in FIGS. 1, 2a and 2b refers to a so-called full-face mask 12 wherein the cushion/mask flap 10 surrounds the nose and mouth of the user 50. These full-faced masks 12 often comprise an additional cushion support 24, also referred to as forehead support 24, which may be integrally connected to the mask shell, and which is arranged to engage the forehead of the patient 50. The additional cushion support/forehead support 24 mainly serves to balance the forces that the mask 12 exerts on the face of the patient 50 and is mechanically stabilized to mask shell as well as to serve or correct a comfortable fit of the mask. A gas supplying hose (not shown) is usually connected to a connection interface 14 that is preferably attached to or integrated into the mask shell 30. The mask may include the patient-contacting element according to the present invention.

[0078] As illustrated in FIG. 3 a patient-contacting element according to the present invention is shown in cross-section of the air-permeable mask cushion 10 configured to provide a substantially air-tight seal with the user's skin during use. This may be obtained by providing a thin layer of a substantially air-tight material, such as a silicone film, on the contacting area with the skin/face of the user 50. Other materials are also conceivable for the layer such as any kind of polymer film, polymer membrane, closed cell foam or coated textile fabric. The patient-contacting element 10 comprises in this example two gas-permeable elements 16 which are disposed within the patient-contacting element and contact the thin layer of a substantially air-tight material or substantially air-tight boundary. However, any number of gas-permeable elements 16 may be employed. Gas 40 is provided via an inlet 14 and passes from the inner space 52 of the patient-contacting element 16 to the patient-contacting elements 16 through an opening 20 provided in a first layer 18 of a substantially air-tight material sharing the gas-permeable element 16 from the inner space 52 of the patient-contacting element 10. It is clear that the number of openings 20 is not particularly restricted. In general, any number of openings 20 may be employed. Within the gas-permeable elements 16 flow of gas is possible in essentially all directions as indicated by reference number 40. The gas may also stream out the gas-permeable element 16 through opening 20. A silicon sealing flap 28 may be formed between the inner space 52 of the patient-contacting element and the outer space 54.

[0079] FIG. 4 shows another embodiment of the present invention. The schematically shown patient-contacting element 10 comprises two gas-permeable elements 16 provided with several openings 20, respectively, which are in fluidic connection with the inner space of the patient-contacting element. The inlet 14 receives at least part of the flow of gas 40 and provides a part of flow of gas 40 to the gas-permeable elements 16 via openings 20. Again, the cushion 10 is configured to provide a substantially air-tight seal with the user's 50 skin during use.

[0080] FIG. 5 still shows another embodiment of a schematically shown patient-contacting element comprising three inlets 14 one of them directly connected with the inner part of the cushion for providing air directly to a user 50. Two other inlets 14 provide air directly to two gas-permeable elements 16, respectively. The part of flow of gas provided to each of the gas-permeable elements 16 leaves the gas-permeable element 16 through openings 20 to the inner space of the contacting element which is indicated by reference number 40 describing an unidirectional flow of gas.

[0081] The patient-contacting element 10 exemplarily shown in FIG. 6 may function as a support structure for traditional silicon sealing flaps, such as sealing flap 28 attached to the face of support. The patient-contacting element 10 has two silicon sealing membranes 22, 26 sharing each of the gas-permeable elements 16 from the outer space 54 and user's 50 skin/face. A flow of gas 40 is provided via inlet 14 to the gas-permeable elements 16. The first layer 18 of a substantially air-tight material between the gas-permeable element 16 and the inner space 52 of the patient-contacting element has several openings 20 provided therein permitting bidirectional flow of gas thereby enabling changing of the pressure within the gas-permeable elements 16.

[0082] FIGS. 7a to c schematically show the optimal compression range for constant, non-constant and air-assisted cushion stiffness. In these figures compression is shown by x-axis 60, whereas pressure is indicated by y-axis 62. Line 64 generally shows minimal pressure for sealing, line 66 generally shows the maximum (tolerable) pressure at which red marks may form on a user's face. The optimal compression range 68 is within boundaries 60a and 60b.

[0083] As indicated in FIG. 7a, the compression of the cushion should be in a rather small optimal compression range 68 for constant cushion stiffness, i.e. compression 70. As may be derived from FIG. 7b, a non-constant cushion compression stiffness again indicated by line 70 significantly increases the optimal compression range 68 and assists in realizing a compression in all places in the optimal compression range. This tailored stiffness however only performs well for a certain/specific value CPAP pressure.

[0084] For an optimal performance, the cushion stiffness needs to be adapted for different CPAP pressures. This case is shown in FIG. 7c having a broad optimal compression range within lower and upper boundaries 60a and 60b. Hence, the advantages of the present patient-contacting element 10 as well as the patient interface 12 comprising such a patient-contacting element 10 are proper sealing and giving the mask a stable position with respect to the user's 50 face. Therefore a secondary structure, such as forehead support 24 (compare FIG. 2a), may be avoided as this secondary structure will lead to lower pressure peaks unless made very soft. If this secondary structure, however, is made too soft it will become unstable, unless stabilized by an internal pressure as proposed herein.

[0085] The part of the silicon cushion 10 which is not supported by a secondary structure, such as any kind of cushion support structure, will very easily lose the contact with the face due to wrinkling or other stiffness effects (e.g. when stretch is needed to follow the facial contour) because there is no driving force towards the face at all as soon as the CPAP pressure penetrates between the cushion 10 and the face of the user 50. In contrast to this, the present cushion material will add a small extra pressure in the face direction. Additional to this, the substantially air-tight outer layer of the cushion can be chosen very soft and put under a pre-stress (by compressing the cushion inside material) for avoiding wrinkles.

[0086] 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.

[0087] 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.

[0088] Any reference signs in the claims should not be construed as limiting the scope.