Patent Description:
A patient dealing with respiratory illness, for example chronic obstructive pulmonary disease (COPD), can have difficulty engaging in effective respiration. This difficulty may be the result of a variety of causes, including a breakdown of lung tissue, dysfunctions of the small airways, excessive accumulation of sputum, infection, genetic disorders, or cardiac insufficiency. With some respiratory illnesses, it is useful to provide a patient with a therapy that can improve the ventilation of the patient. The patient can be provided with high flow therapy using a respiratory therapy system that includes a gases source, a patient interface that may be used to transmit gases to an airway of a patient, and a conduit extending between the gases source and the patient interface. The patient interface is typically not sealed. The gases may be heated and humidified before delivery to the patient.

Obstructive Sleep Apnea (OSA) is a sleep disorder in which muscles that normally hold open the airway collapse, temporarily sealing the airway. The sleep pattern of an OSA sufferer is characterized by repeated sequences of snoring, breathing difficulty, lack of breathing, waking with a start, and then returning to sleep. The respiratory therapy of Continuous Positive Airway Pressure (CPAP) can be used to splint the airway and reduce or eliminate the occurrence of OSA. The patient can be provided with CPAP therapy using a respiratory therapy system that includes a gases source, a patient interface that may be used to transmit gases to an airway of a patient, and a conduit extending between the gases source and the patient interface. The patient interface is typically sealed. The gases may be heated and humidified before delivery to the patient.

<CIT> discloses a patient interface that includes a support body having a cushion and cheek interfaces. Collectively, the cushion and cheek interfaces operate to distribute compressive forces exerted on the user's face. The support body of the patient interface is constructed from a flexible material to impart additional adjustability to the cheek interfaces. The support body also has arcuate eyelets designed to provide a hinge between the headgear assembly and the support body.

According to the present invention there is provided a fixation structure as defined in claim <NUM>.

Patient interfaces for respiratory therapy systems can include nasal cannulas, nasal masks, oral masks, oro-nasal masks, full face masks, nasal pillows masks, or endotracheal tubes. When a patient interface is fitted to a patient, gases are channeled through nasal delivery elements of the patient interface to the patient's airway (for example, the tubular prongs of a nasal cannula, which rest in the nares of the patient). In some cases, it is useful to attach the patient interface to the patient's face. One option is to position an adhesive pad on the patient's face, the adhesive pad having a mechanical fastener on a side of the adhesive pad that faces away from the patient's face. The mechanical fastener couples with a complementary fastener attached to the patient interface. However, depending on factors including the shape of the adhesive pad, separation of the mechanical fastener from the complementary fastener can cause the adhesive pad to be undesirably dislodged from the patient's face. Solutions to the above difficulties, or systems or apparatus that provide a useful alternative, are sought.

In accordance with certain features, aspects and advantages of one or more of the embodiments disclosed herein, a fixation structure is disclosed. The fixation structure is adapted to cooperate with a patient interface to secure the patient interface on a face of a patient. The fixation structure comprises a first edge adapted to face toward a nose or mouth of the patient in use. The fixation structure comprises a second edge adapted to face away from the nose or mouth of the patient in use. The first edge is substantially flat or straight. The first and second edges are substantially the same width.

The first and second edges can be identical in shape and size. The fixation structure can comprise a substantially flat or straight third edge extending between the first and second edges. The fixation structure can comprise substantially flat or straight third and fourth edges extending between the first and second edges. The second edge can be substantially rounded. The fixation structure can comprise a periphery with a substantially triangular shape. The fixation structure can comprise a periphery with a substantially curved shape.

The fixation structure can comprise a first fastener adapted to interface with a complementary second fastener of an attachment structure of the patient interface. The first fastener can be secured or adhered to a first surface of the fixation structure that faces away from the patient's face in use. The first fastener can cover substantially the entire first surface of the fixation structure.

The fixation structure can comprise opposing third and fourth edges extending between the first and second edges. The first fastener can extend substantially along the entirety of the first surface of the fixation structure between the first and second edges and only partly between the opposed third and fourth edges.

The first fastener can extend from the first edge to a position along the length of the fixation structure between the first and second edges. The fixation structure can comprise opposing third and fourth edges extending between the first and second edges. The first fastener can extend from the first edge to a position along the length of the fixation structure between the first and second edges. The first fastener can extend from the third edge to a position along the width of the fixation structure between the third and fourth edges.

The first fastener can comprise a hooked fastener adapted to interface with a complementary looped fastener of the attachment structure of the patient interface. The hooked fastener can comprise hooks that extend outwardly from a side of the fixation structure that faces away from the patient's face. The hooks can extend toward the first and/or second edges of the fixation structure.

The hooks can be generally parallel with the first and second edges and generally perpendicular with the third and fourth edges when the third edge is substantially flat.

The fixation structure can be of substantially uniform thickness.

The fixation structure can be constructed from a hydrocolloid-based adhesive. The fixation structure can be constructed from a silicone-based adhesive.

The fixation structure can be adapted to facilitate connecting the fixation structure to the face of the patient. For example, the patient-facing region of the fixation structure can be constructed from a material that in use substantially maintains a constant level of adherence to the skin for at least a predetermined period of time after application to the skin.

Additionally, in accordance with certain features, aspects and advantages of one or more of the embodiments disclosed herein, a fixation structure is disclosed. The fixation structure is adapted to cooperate with a patient interface to secure the patient interface on a face of a patient. The fixation structure comprises a body with a patient-facing region adapted to adhere to the face of the patient. The fixation structure comprises a first fastener adhered to the body. The first fastener is adapted to interface with a complementary second fastener of an attachment structure of the patient interface. The body is constructed from a hydrocolloid-based adhesive or a silicone-based adhesive.

Additionally, in accordance with certain features, aspects and advantages of one or more of the embodiments disclosed herein, a fixation structure is disclosed. The fixation structure is adapted to cooperate with a patient interface to secure the patient interface on a face of a patient. The fixation structure comprises a first edge adapted to face toward a nose or mouth of the patient in use. The fixation structure comprises a second edge adapted to face away from the nose or mouth of the patient in use. The fixation structure comprises a hooked fastener adapted to interface with a complementary looped fastener of an attachment structure of the patient interface. The hooked fastener extends at least partially between the first and second edges. The hooked fastener comprises hooks that extend toward the first and/or second edges of the fixation structure.

Additionally, in accordance with certain features, aspects and advantages of one or more of the embodiments disclosed herein, a fixation structure is disclosed. The fixation structure is adapted to cooperate with a patient interface to secure the patient interface on a face of a patient. The fixation structure comprises a first edge adapted to face toward a nose or mouth of the patient in use. The fixation structure comprises a second edge adapted to face away from the nose or mouth of the patient in use. The fixation structure comprises a third edge extending between the first and second edges. The third edge comprises a concave curve.

The fixation structure can comprise a fourth edge extending between the first and second edges. The fourth edge can comprise a concave curve that is shaped to match a shape of an under-eye region of the patient. The third and fourth edges can be opposed.

The fixation structure can comprise a first fastener adapted to interface with a complementary second fastener of an attachment structure of the patient interface. The first fastener can be fixed to a side of the fixation structure that faces away from the patient. A midpoint of the first fastener can be offset from a first centerline or central portion that is midway between the first and second edges of the fixation structure. The first fastener can be positioned such that it is closer to the first edge than to the second edge. The midpoint of the first fastener can be on a second centerline or central portion that is midway between the third and fourth edges of the fixation structure.

Additionally, in accordance with certain features, aspects and advantages of one or more of the embodiments disclosed herein, a fixation structure is disclosed. The fixation structure is adapted to cooperate with a patient interface to secure the patient interface on a face of a patient. The fixation structure comprises a first edge adapted to face toward a nose or mouth of the patient in use. The fixation structure comprises a second edge adapted to face away from the nose or mouth of the patient in use. The fixation structure comprises a third edge extending between the first and second edges. The third edge projects farther from a centerline or center portion of the fixation structure at portions of the third edge proximal to the first and second edges than at portions of the third edge distal from the first and second edges.

The portions of the third edge proximal to the second edge can project farther from the centerline or central portion of the fixation structure than portions of the third edge proximal to the first edge.

Additionally, in accordance with certain features, aspects and advantages of one or more of the embodiments disclosed herein, a fixation structure is disclosed. The fixation structure is adapted to cooperate with a patient interface to secure the patient interface on the face of the patient. The fixation structure comprises a body adapted to adhere to the face of the patient. The body is constructed at least in part from a material having a low hygroscopicity.

Additionally, in accordance with certain features, aspects and advantages of one or more of the embodiments disclosed herein, a fixation structure is disclosed. The fixation structure is adapted to cooperate with a patient interface to secure the patient interface on the face of the patient. The fixation structure comprises a body adapted to adhere to the face of the patient. The body is constructed at least in part from a material having a low Young's modulus.

The body can have a thickness that allows the body to flex in response to movements of the patient's face. The body can have a thickness that is between <NUM> and <NUM>. The thickness of the first fastener can be less than the thickness of the body. The thickness of the first fastener can be at least a quarter of the thickness of the body.

The body can comprise a silicone-based adhesive that conforms to the shape of the patient's skin in use. The body can comprise a hydrocolloid-based adhesive.

Additionally, in accordance with certain features, aspects and advantages of one or more of the embodiments disclosed herein, a fixation structure is disclosed. The fixation structure cooperates with a patient interface to secure the patient interface on the patient's face. The fixation structure comprises a body that adheres to the patient's face in use. The body comprises a first fastener that couples with a complementary second fastener of an attachment structure of the patient interface. The body comprises an adhesive that adheres to the skin on the patient's face in use. The adhesive substantially immediately reaches a maximum amount of adherence to the skin upon application of the adhesive to the skin.

The adhesive can substantially immediately flow into gaps in the skin upon application of the adhesive to the skin. The adhesive can be a silicone-based adhesive. The adhesive can require less force to remove than a similarly sized hydrocolloid-based adhesive applied to the skin of the patient's face.

Additionally, in accordance with certain features, aspects and advantages of one or more of the embodiments disclosed herein, a fixation structure is disclosed. The fixation structure cooperates with a patient interface to secure the patient interface on the patient's face. The fixation structure comprises a first edge that faces toward a patient's nose or mouth in use. The fixation structure comprises a second edge that faces away from the patient's nose or mouth in use. The fixation structure comprises a plurality of slits that facilitate flexibility of the fixation structure.

Additionally, in accordance with certain features, aspects and advantages of one or more of the embodiments disclosed herein, a patient interface system is disclosed. The patient interface system comprises a patient interface comprising an attachment structure secured to a patient-facing portion of the patient interface. The attachment structure couples with a fixation structure secured to the face to fasten the patient interface to the face in use. The fixation structure may be the same or similar to any of the fixation structures described in the passages above or elsewhere in the specification with reference to the accompanying figures.

The patient interface can comprise a first body adapted to rest on a first portion of the patient's face, a second body adapted to rest on a second portion of the patient's face, and a bridge linking the first and second bodies.

The attachment structure can be secured to patient-facing regions of the first and/or second bodies.

The patient interface can comprise a nasal cannula, nasal mask, oral mask, oro-nasal mask, full face mask, unsealed oro-nasal interface, nasal pillows mask, endotracheal tube, or other such respiratory interface.

Additionally, in accordance with certain features, aspects and advantages of one or more of the embodiments disclosed herein, a fixation structure for securing a patient interface on a face of a patient comprises a first edge; a second edge opposing the first edge, such that in use on the patient's face the second edge is farther away than the first edge from the patient's nose or mouth; and opposing third and fourth edges extending between the first and second edges. Portions of the third edge that are closer to the first and second edges project farther from a centerline or center portion of the fixation structure than do portions of the third edge that are farther from the first and second edges.

Portions of the third edge that are closer to the second edge can project farther from the centerline or center portion of the fixation structure than do portions of the third edge that are closer to the first edge. The third edge can comprise a concave curve. The fourth edge can comprise a concave curve shaped to match a shape of an under-eye region of the patient.

The fixation structure can comprise a first side extending between the first and second edges. The first side can face away from the patient's face and toward the patient interface in use. The first side can comprise a first fastener that is attachable to a complementary fastener of an attachment structure of the patient interface. The first fastener can be positioned closer to the first edge than to the second edge. A midpoint of the first fastener can be offset from a centerline or central portion midway between the first and second edges. A midpoint of the first fastener can be on a centerline or central portion midway between the third and fourth edges.

At least a portion of the first side not covered by the first fastener can comprise a gripping or bearing region. The first fastener can extend from the first edge to a position along a length of the first side between the first and second edges. A length of the first fastener between the first and second edges can be less than a length of the first side between the first and second edges. A ratio of the length of the first fastener to the length of the first side can be between <NUM> and <NUM>.

The first fastener can extend substantially the entirety between the first and second edges and only partly between the third and fourth edges, and the first fastener can extend from the third edge to a position along a width of the first side between the third and fourth edges. The first fastener can extend from the first edge to a position along a length of the first side between the first and second edges, and the first fastener can extend from the third edge to a position along a width of the first side between the third and fourth edges.

The first fastener can comprise a hooked fastener that is removably attachable to a complementary looped fastener of the attachment structure of the patient interface. The hooked fastener can comprise a plurality of hooks that extend outwardly from the first side. At least some of the plurality of hooks can extend toward the first and/or second edges. At least some of the plurality of hooks can be generally parallel to the first and second edges and generally perpendicular to the third and fourth edges.

The first fastener can comprise a plurality of slits that facilitate flexibility of the first fastener. At least some of the plurality of slits can extend to at least one of the first, second, third, or fourth edges. At least some of the plurality of slits can be arranged in columns of slits that extend to the third and fourth edges in alternation. Each of the columns of slits can comprise slits with semicircular or crescent shapes that face the opposite direction to, and are at least partially offset toward the third or fourth edge from, semicircular or crescent shapes of slits in an adjacent column.

At least some of the plurality of slits can extend toward the third and fourth edges. At least some of the plurality of slits that are closer to the first and second edges can be shorter than at least some of the plurality of slits that are farther from the first and second edges. At least some of the plurality of slits can fail to extend across a centerline or central portion midway between the third and fourth edges.

At least one of the plurality of slits can have a serpentine shape. Two of the plurality of slits can have serpentine shapes, one of the serpentine slits can extend toward the first edge, and the other of the serpentine slits can extend toward the second edge.

At least some of the plurality of slits can have zig-zag shapes.

The fixation structure can comprise a second side extending between the first and second edges. The second side can face toward the patient's face and away from the patient interface in use. The second side can comprise a second fastener that is attachable to the patient's face. The second fastener can comprise an adhesive that is removably attachable to the face of the patient. The adhesive can be a hydrocolloid-based adhesive. The adhesive can be a silicone-based adhesive. The adhesive can comprise a material that in use substantially maintains a constant level of adherence to the patient's face for at least a predetermined period of time after application to the face. The adhesive can comprise a material that in use substantially conforms to the shape of the patient's face.

The fixation structure can comprise a material with low hygroscopicity. The fixation structure can comprise a material with a low Young's modulus. The fixation structure can have a substantially uniform thickness. The fixation structure can have a thickness that allows the fixation structure to flex in response to movements of the patient's face. The fixation structure can have a thickness that is between <NUM> and <NUM>.

Additionally, in accordance with certain features, aspects and advantages of one or more of the embodiments disclosed herein, a fixation structure for securing a patient interface on a face of a patient comprises a first edge; a second edge opposing the first edge, such that in use on the patient's face the second edge is farther away than the first edge from the patient's nose or mouth; a first side extending between the first and second edges, the first side facing away from the patient's face and toward the patient interface; and a second side opposing the first side. The first side comprises a first fastener, the first fastener attachable to a complementary fastener of an attachment structure of the patient interface. The second side comprises a second fastener attachable to the patient's face. The first edge is substantially straight. The first and second edges are substantially the same width.

The first and second edges can be substantially the same in shape and size. The second edge can be substantially rounded. The fixation structure can comprise a periphery with a substantially triangular shape. The fixation structure can comprise a periphery that is substantially curved. The fixation structure can comprise a substantially straight third edge extending between the first and second edges. The fixation structure can comprise opposing substantially straight third and fourth edges extending between the first and second edges.

Additionally, in accordance with certain features, aspects and advantages of one or more of the embodiments disclosed herein, a patient interface system comprises a fixation structure according to any one of the previously disclosed embodiments; and a patient interface comprising one or more attachment structures facing toward a patient's face in use. Each of the one or more attachment structures comprises a fastener that is attachable to a complementary fastener of the fixation structure.

The patient interface can comprise a first body adapted to rest on a first portion of the face. The patient interface can comprise a second body adapted to rest on a second portion of the face. The patient interface can comprise a bridge linking the first and second bodies. One or both of the first and second bodies each can comprise one of the attachment structures. One or both of the first and second bodies each can comprise a first edge and a second edge opposing the first edge. In use on the patient's face, the second edge can be farther away than the first edge from the patient's nose or mouth. The second edge can comprise a detachment structure to ease removal of the patient interface from the patient's face. The patient interface can comprise a nasal cannula, nasal mask, oral mask, oro-nasal mask, full face mask, unsealed oro-nasal mask, nasal pillows mask, or endotracheal tube.

Specific embodiments and modifications thereof will become apparent to those skilled in the art from the detailed description herein having reference to the figures that follow.

<FIG> illustrates an example respiratory therapy system <NUM>. A patient <NUM> is receiving heated and humidified gases through a patient interface <NUM>, shown in this example as a nasal cannula assembly, connected to a humidified gases transportation pathway or inspiratory conduit <NUM> that in turn is connected to a humidifier <NUM> (including a humidification chamber <NUM>) that is supplied with gases from a blower <NUM> or other appropriate gases supply. The gases can be supplied from a source that is external to and/or separate from the respiratory therapy system <NUM>, or from a source that is internal to and/or integrated with the respiratory therapy system <NUM>. Headgear <NUM> is provided to support and retain the patient interface <NUM> against the patient's face. The inspiratory conduit <NUM> is connected to an outlet <NUM> of the humidification chamber <NUM> which contains a volume of water <NUM>. The humidification chamber <NUM> is preferably formed from a plastics material and may have a highly heat conductive base (for example an aluminum base) which is in direct contact with a heater plate <NUM> of the humidifier <NUM>. The humidifier <NUM> is provided with a control mechanism or electronic controller <NUM> that may include a microprocessor based controller executing computer software commands stored in associated memory. Gases flowing through the inspiratory conduit <NUM> are passed to the patient's airway through the patient interface <NUM>.

The controller <NUM> receives input from sources such as input means (e.g., a dial <NUM>) through which a user (e.g., a nurse or other healthcare provider) may, for example, set a predetermined required value (preset value) of humidity or temperature of the gases supplied to the patient. In response to the user-set humidity or temperature value input via the dial <NUM> and other possible inputs such as internal sensors that sense gases flow or temperature, or parameters calculated by the controller <NUM>, the controller <NUM> determines when (or to what level) to energize the heater plate <NUM> to heat the volume of water <NUM> within the humidification chamber <NUM>. As the volume of water <NUM> within the humidification chamber <NUM> is heated, water vapor begins to fill the volume of the chamber above the water's surface and is passed out of the outlet <NUM> of the humidification chamber <NUM> with the flow of gases (for example air) provided from the gases supply means or blower <NUM> which enters the humidification chamber <NUM> through an inlet <NUM>. It should be noted that it is possible to obtain the relationship between the humidity of the gases in humidification chamber <NUM> and the temperature of the heater plate <NUM>. Accordingly, it is possible to utilize the temperature of the heater plate <NUM> in an algorithm or a look-up table to determine the humidity of the gases.

The blower <NUM> may be provided with a variable speed pump or fan <NUM> that draws air or other gases through the blower inlet <NUM>. The speed of the variable speed pump or fan <NUM> may be controlled by a further control means or electronic controller <NUM> (or alternatively the function of the controller <NUM> could be carried out by the controller <NUM>) in response to inputs from the controller <NUM> and a user-set predetermined required value (preset value) of pressure and/or fan speed via one or more input devices, such as a dial <NUM>.

A heating element <NUM> may be provided within the conduit <NUM> to help prevent condensation of the humidified gases within the conduit <NUM>. Such condensation is due to the temperature of the walls of the conduit <NUM> being close to the ambient temperature, (being the temperature of the surrounding atmosphere) which is usually lower than the temperature of the humidified gases within the conduit <NUM>. The heating element <NUM> effectively replaces the energy lost from the gases through conduction and convection during transit through the conduit <NUM>. Thus the heating element <NUM> ensures the gases delivered are at an optimal temperature and humidity.

In the illustrated configurations, the patient interface <NUM> includes a nasal cannula. In some alternative configurations, the patient interface <NUM> may include a sealing or non-sealing interface. For example, the patient interface <NUM> may include a nasal mask, an oral mask, an oro-nasal mask, a full face mask, a nasal cannula, an unsealed oro-nasal interface, a nasal pillows mask, an endotracheal tube, a combination of the above, or some other gases conveying system or apparatus. Certain features, aspects and advantages of the illustrated nasal cannula may be envisaged in other such patient interfaces.

Referring to <FIG>, the patient interface <NUM> is shown. The patient interface <NUM> can be generally shaped or configured such that it substantially matches the contours of the face. The patient interface <NUM> includes first and second nasal delivery elements 202A, 202B adapted to rest in the patient's nares. The illustrated nasal delivery elements 202A, 202B are substantially tubular and direct gases passing through the patient interface <NUM> to the patient. The nasal delivery elements 202A, 202B can be shaped and angled such that they generally extend inwardly toward the patient's septum in use. The nasal delivery elements 202A, 202B end in tips 202A', 202B'. In use, the tips 202A', 202B' point toward the back of the patient's head. It should be understood that in some configurations, the nasal delivery elements 202A, 202B could have different shapes. For example, although the average cross-section of the nasal delivery elements 202A, 202B in the illustrated configurations is substantially circular, in some configurations the cross-section of the nasal delivery elements 202A, 202B could be substantially ellipsoidal, substantially square, or substantially rectangular. In some configurations, the cross-section of the nasal delivery elements 202A, 202B could vary along the length of the nasal delivery elements 202A, 202B. In some configurations, the first and second nasal delivery elements 202A, 202B may have different characteristics. For example, the first nasal delivery element 202A may be smaller or shorter than the second nasal delivery element 202B. In some configurations, only one nasal delivery element may be used. In some configurations, more than two (for example, three or four) nasal delivery elements may be used.

The first and second nasal delivery elements 202A, 202B extend from first and second bodies 206A, 206B of the patient interface <NUM>. The first and second bodies 206A, 206B include internal gases delivery lumens 210A, 210B, that receive gases from gases inlets 208A, 208B of the first and second bodies 206A, 206B, and channel the gases to the first and second nasal delivery elements 202A, 202B. The gases inlets 208A, 208B couple with a pair of gases delivery conduits 218A, 218B (see <FIG>). In the illustrated configuration, the gases delivery conduits 218A, 218B are integrally formed or inseparably connected to the gases inlets 208A, 208B. The gases delivery conduits 218A, 218B in turn are integrally formed or inseparably connected to a gases conduit connector <NUM>. The gases conduit connector <NUM> releasably couples with a complementary connector <NUM> in pneumatic communication with the gases conduit <NUM> (described elsewhere in this disclosure with reference to <FIG> as inspiratory conduit <NUM>). Other configurations are contemplated. For example, in some configurations, the first and second nasal delivery elements 202A, 202B may receive gases from a single internal gases delivery lumen positioned in one of the first or second bodies 206A, 206B. The single internal gases delivery lumen in turn may receive gases from a single gases delivery conduit.

In some configurations, the one or more gases inlets 208A, 208B may couple directly with the gases conduit <NUM> (or indirectly via the complementary connector <NUM> and/or the gases conduit connector <NUM>). In some such configurations, the first and/or second bodies 206A, 206B may be integrally formed or may be in the form of a single continuous assembly together with the gases conduit <NUM>. In some configurations one or more of the gases delivery conduits 218A, 218B are removably coupled to one or more of the gases inlets 208A, 208B. In some configurations one or more of the gases delivery conduits 218A, 218B are removably coupled to the gases conduit connector <NUM>.

The first and second bodies 206A, 206B of the patient interface <NUM> are adapted to rest on the patient's face. In the illustrated configuration, the first and second bodies 206A, 206B are adapted to rest on opposing cheeks of the patient's face. To fix the first and second bodies 206A, 206B in place on the patient's face, patient-facing regions of the first and second bodies 206A, 206B are provided with attachment structures 216A, 216B. The attachment structures 216A, 216B are adapted to maintain the patient interface <NUM> in a desired alignment with the face, such that the nasal delivery elements 202A, 202B may, in a non-limiting example, be comfortably and non-sealingly positioned in the nares.

The attachment structures 216A, 216B couple with or attach to fixation structures that are adhered to the face in use. In some configurations, the attachment structures 216A, 216B and the fixation structures can be structured such that they are complementary to one another. For example, the attachment structures 216A, 216B may include 'loop' portions (constructed from, for example, textiles or plastics) that are adhered or otherwise secured to patient-facing regions of the first and second bodies 206A, 206B, and the fixation structures may be adhered or otherwise secured to the face and may include 'hook' pads. The attachment structures 216A, 216B and the fixation structures couple or attach to each other via, for example, a 'hook-and-loop' style connection. Other configurations are contemplated. In some configurations, the attachment structures 216A, 216B may interface directly with the face, for example, through the use of adhesive pads or other structures. In some configurations, a single attachment structure may be used, or more than two, for example, three or four, attachment structures may be used.

In some configurations, the attachment structures 216A, 216B may include features other than 'loop' portions. For example, the attachment structures 216A, 216B may include 'hook' portions that couple with or attach to complementary 'loop' portions on the fixation structures. As another example, the attachment structures 216A, 216B may include snap-fit features or other mechanical interlock features that couple with or attach to features on the fixation structures. In some configurations, the patient interface <NUM> may additionally include headgear adapted to retain the patient interface <NUM> in a desired orientation or alignment on the face. The headgear may include, for example, one or more straps configured to extend around the patient's head, buckles to adjust the tightness of the straps by modifying the effective length of the straps, caps, coifs, hats, helmets, and/or one or more other features.

A bridge <NUM> connects the first and second bodies 206A, 206B. The bridge <NUM> is an extension of the first and/or second bodies 206A, 206B. In some embodiments, the bridge <NUM> includes no internal gases lumen. The bridge <NUM> serves to help keep the nasal delivery elements 202A, 202B in a desired orientation with respect to one another. Other configurations are contemplated. For example, in some configurations, the bridge <NUM> could be constructed from a different material to the first and second bodies 206A, 206B. Alternatively, the bridge <NUM> could be constructed from the same material as the first and second bodies 206A, 206B. In some configurations, the bridge <NUM> may be open to provide transmission of gases between the first and second bodies 206A, 206B, for example, via an internal gases lumen that fluidly couples the nasal delivery elements 202A, 202B. In some such configurations, only one of the bodies 206A, 206B includes an internal gases lumen and/or gases inlet. In some configurations, the bridge <NUM> extends between a first connection point on the first body 206A and a second connection point on the second body 206B.

As seen in <FIG>, the first and second bodies 206A, 206B may decrease in width as they extend toward the nasal delivery elements 202A, 202B and the bridge <NUM>. The attachment structures 216A, 216B are positioned on relatively wide portions of the first and second bodies 206A, 206B at or near the outer edges of the first and second bodies 206A, 206B to improve stability of the patient interface <NUM> on the face when the attachment structures 216A, 216B are used together with the fixation structures. For example, the attachment structures 216A, 216B can be positioned at or near distal portions of the first and second bodies 206A, 206B relative to the nasal delivery elements 202A, 202B. The attachment structures 216A, 216B may substantially cover the patient-facing regions of the first and second bodies 206A, 206B. The attachment structures 216A, 216B may at least partially cover the patient-facing regions of the first and second bodies 206A, 206B. The attachment structures 216A, 216B can be positioned within at least partially recessed regions of the first and second bodies 206A, 206B.

With further reference to <FIG> and <FIG>, outer edges of the first and second bodies 206A, 206B can include detachment structures 212A, 212B. The detachment structures 212A, 212B are positioned on a non-patient-facing region of the bodies 206A, 206B. The detachment structures 212A, 212B are spaced apart from the gases inlets 208A, 208B. In the illustrated configuration, the detachment structures 212A, 212B are tabs that include inner regions of reduced thickness relative to adjacent portions of the bodies 206A, 206B. Outside of the inner regions of the tabs and toward the outer edge of the bodies 206A, 206B, the tabs additionally include outer regions of normal thickness or increased thickness relative to the same adjacent portions of the bodies 206A, 206B. The outer regions may be grasped by the patient or another person (for example, a healthcare professional such as but not limited to a nurse or physician) and pulled. When pulled, the outer regions may rotate around the inner regions and sufficient forces may be exerted on the patient interface <NUM> such that the attachment structures 216A, 216B are detached from the fixation structures present on the face. The detachment structures 212A, 212B thus may be used to more easily detach the patient interface <NUM> from the face. Other configurations are contemplated. For example, in some configurations, one of the detachment structures 212A, 212B may be positioned on one of the first or second bodies 206A, 206B of the patient interface <NUM>. In some configurations, the patient interface <NUM> may include more than two, for example, three or four, detachment structures. In some configurations, the detachment structures 212A, 212B may be positioned on other portions of the bodies 206A, 206B, or on other portions of the patient interface <NUM>. In some configurations, the detachment structures 212A, 212B may include structures other than tabs. For example, the detachment structures 212A, 212B may include flat extensions of the first and/or second bodies 206A, 206B that can be pulled or otherwise manipulated to separate the patient interface <NUM> from the face.

<FIG> shows a patient-facing region <NUM> of a fixation structure <NUM>, and <FIG> shows an interface-facing region <NUM>' of the fixation structure <NUM>. The patient-facing region <NUM> removably couples with or adheres to the patient's face. The interface-facing region <NUM>' of the fixation structure <NUM> attaches to the patient interface <NUM> to removably couple the patient interface <NUM> to the patient's face. The fixation structure <NUM> removably joins with the attachment structures 216A, 216B as described elsewhere in this disclosure with reference to <FIG>.

In the illustrated configuration, the fixation structure <NUM> includes a body <NUM>. The body <NUM> is of substantially uniform thickness. In other configurations, the body <NUM> may be of variable thickness along the length L and/or width W of the body <NUM>. The body <NUM> includes a first edge <NUM> adapted to face toward the patient's nose or mouth in use. In the illustrated configuration, the first edge <NUM> is substantially rounded and tapers in width to form an extension or knob of the body <NUM>. The body <NUM> additionally includes a second edge <NUM>, which is a lateral edge with respect to the patient's face, and therefore adapted to face away from the patient's nose or mouth in use. In the illustrated configuration, the second edge <NUM> is substantially rounded and slightly tapers in width. Opposed curved third and fourth edges 308A, 308B extend between the first and second edges <NUM>, <NUM> of the body <NUM>.

The interface-facing region <NUM>' of the fixation structure <NUM> includes an interface-facing fixation element <NUM>'. The interface-facing fixation element <NUM>' engages with the attachment structures 216A, 216B to secure the patient interface <NUM> to the patient's face in use. In the illustrated configuration, the interface-facing fixation element <NUM>' is a hooked pad that removably joins with a looped pad of one of the attachment structures 216A, 216B (e.g. for a hook-and-loop style connection). The hooked pad may be joined to the fixation structure <NUM> by a number of means, including but not limited to the use of adhesives, ultrasonic welding, high frequency welding, stitching, or chemical bonding. In other configurations, the interface-facing fixation element <NUM>' may include other structures or elements adapted to couple with or attach to the attachment structures 216A, 216B, including but not limited to catches, which can couple with complementary latches of the attachment structures 216A, 216B or latches to couple with or attach to complementary catches of the attachment structures 216A, 216B, complementary adhesives, pins, clasps, or other mechanical fasteners.

The patient-facing region <NUM> is constructed from a material that can be removably joined to the patient's face. In the illustrated configuration, the material is an adhesive material, for example a hydrocolloid-based adhesive material, a zinc oxide-based adhesive material, or a hydrogel-based material.

<FIG> shows an exemplary embodiment of the fixation structure <NUM> and the interface-facing fixation element <NUM>'. In the illustrated configuration, the interface-facing fixation element <NUM>' is a hooked pad with a serpentine shape. The serpentine shape defines gaps <NUM> between adjacent masses of the interface-facing fixation element <NUM>'. The gaps <NUM> improve the flexibility of the interface-facing fixation element <NUM>', particularly when the fixation structure <NUM> is placed under torsion around an axis substantially parallel to the first and/or second edges <NUM>, <NUM>. The gaps <NUM> can include cuts, slits, fenestrations, or thin regions formed in the interface-facing fixation element <NUM>'. The interface-facing fixation element <NUM>' can be configured to exhibit increased flexibility under torsion around the axis substantially parallel to the first and/or second edges <NUM>, <NUM> by altering the material configuration. For example, in some configurations the interface-facing fixation element <NUM>' could be constructed from a mechanically anisotropic material that exhibits increased flexibility when under torsion around the axis substantially parallel to the first and/or second edges <NUM>, <NUM>. In some configurations, the interface-facing fixation element <NUM>' could be constructed from multiple materials of varying flexibility. The multiple materials could be stratified along the length of the interface-facing fixation element <NUM>'.

<FIG> illustrate the use of various patterns, for example, of slits, for the interface-facing fixation element <NUM>'. The interface-facing fixation element <NUM>' has a substantially elliptical shape, although in other configurations the interface-facing fixation element <NUM>' can have other shapes, including, but not limited to, rectangular, square, trapezoidal, triangular, or pentagonal shapes. As described with reference to <FIG>, the interface-facing fixation element <NUM>' can include slits or other features that improve the flexibility of the interface-facing fixation element <NUM>'. Various patterns of slits can be used to impart flexibility to the interface-facing fixation element <NUM>'. In some embodiments, the slits extend to at least one edge of the interface-facing fixation element <NUM>'. In some embodiments, the slits do not extend to an edge of the interface-facing fixation element <NUM>'.

<FIG> shows an embodiment of the interface-facing fixation element <NUM>' including a pattern of successive slits that arcuately extend toward a lengthwise edge of the interface-facing fixation element <NUM>'. The slits increase in length toward a center of the interface-facing fixation element <NUM>'.

<FIG> shows an example of the interface-facing fixation element <NUM>' including a pattern of pairs of slits in a first region of the interface-facing fixation element <NUM>' and singular slits in a second region of the interface-facing fixation element <NUM>'. The pairs of slits in the first region of the interface-facing fixation element <NUM>' extend substantially inwardly from the third and fourth edges 308A, 308B of the interface-facing fixation element <NUM>' and increase in length toward a center of the interface-facing fixation element <NUM>'. The singular slits in the second region of the interface-facing fixation element <NUM>' increase in length toward the center of the interface-facing fixation element <NUM>'.

<FIG> shows an example of the interface-facing fixation element <NUM>' including a pattern of slits that alternately extend from opposing widthwise edges of the interface-facing fixation element <NUM>'. The slits increase in length toward a center of the interface-facing fixation element <NUM>'.

<FIG> shows an example of the interface-facing fixation element <NUM>' including a pattern of successive straight slits that increase in length toward a center of the interface-facing fixation element <NUM>'.

Figures 12A-<NUM> illustrate the use of various patterns of slits on embodiments of the interface-facing fixation element <NUM>' having a substantially triangular shape, or a shape similar to the Reuleaux triangle-like shape with rounded edges or 'guitar pick'-like shape shown in <FIG>. However, it should be understood that such patterns of slits could be similarly applied to fixation elements having other shapes. In some embodiments, the slits extend to at least one edge of the interface-facing fixation element <NUM>'. In some embodiments, the slits do not extend to an edge of the interface-facing fixation element <NUM>'.

<FIG> shows an example of the interface-facing fixation element <NUM>' including a pattern of a pair of slits extending from opposing ends of the interface-facing fixation element <NUM>'. As shown, the slits can extend along a portion of the width W and length L of the interface-facing fixation element <NUM>'. In some embodiments, each of the pair of slits has a serpentine shape. The slits can have straightened edges defining each turn or change in direction of the serpentine slit. As illustrated, one or each of the serpentine slits can include substantially parallel widthwise sections linked by lengthwise sections. The lengthwise sections can extend along the edges of the interface-facing fixation element <NUM>', and can extend in a radially outward direction, and/or can extend toward a center of the interface-facing fixation element <NUM>'. In some configurations, the lengthwise sections are at an angle substantially offset from a lengthwise direction (e.g., a longitudinal axis of the interface-facing fixation element <NUM>'). As shown, some configurations have a single, non-serpentine slit that can be positioned between the pair of slits. The single slit can extend at least partially between the third and fourth edges 308A, 308B.

<FIG> shows an example of the interface-facing fixation element <NUM>' including a pattern of a single slit having a serpentine shape with straightened edges defining each turn or change in direction of the serpentine slit.

<FIG> shows an example of the interface-facing fixation element <NUM>' including a pattern of alternating columns of semicircular slits. Each column includes semicircular slits with shapes that face the opposite direction to, and are at least partially offset from, the columns on either side.

<FIG> shows an example of the interface-facing fixation element <NUM>' including a pattern of slits that extend from the third and fourth edges 308A, 308B of the interface-facing fixation element <NUM>' inwardly toward a center of the interface-facing fixation element <NUM>'. The illustrated slits may not extend across the entirety of the interface-facing fixation element <NUM>'.

<FIG> shows an example of the interface-facing fixation element <NUM>' including a pattern similar to that shown in <FIG>. However, in the illustrated interface-facing fixation element <NUM>', the columns of semicircular slits are aligned such that they are closer together than the columns shown in <FIG>. In an embodiment, the semicircular slits can overlap.

<FIG> shows an example of the interface-facing fixation element <NUM>' including a pattern of slits that include 'stair step' or zig-zag shapes.

<FIG> shows an example of the interface-facing fixation element <NUM>' including a pattern of successive straight slits that increase in length toward a center of the interface-facing fixation element <NUM>'. The slits are substantially parallel with the second edge <NUM> of the interface-facing fixation element <NUM>'.

<FIG> shows an example of the interface-facing fixation element <NUM>' including a pattern similar to that shown in <FIG>. However, in the illustrated interface-facing fixation element <NUM>', the centermost slit is straight and substantially parallel to the second edge <NUM> of the interface-facing fixation element <NUM>', and the other slits curve inwardly toward the centermost slit.

Although the illustrated embodiments of the fixation structure <NUM> are useful in aiding in the retention of the patient interface <NUM> on the patient's face, in some cases forces applied to the fixation structure <NUM> can cause the fixation structure <NUM> to be unintentionally lifted from the patient's face, which can be an inconvenience to the patient and/or a medical professional tending to the patient. This may occur because a portion of the forces applied to remove the patient interface <NUM> from the fixation structure <NUM> may be transferred to the fixation structure <NUM>. Force may be applied, for example, in a direction normal to the patient's cheek. To reduce the likelihood of unintentional removal of the fixation structure <NUM> from the patient's cheek, such as upon removal of the patient interface <NUM>, the adhesion of the fixation structure <NUM> to the patient's cheek may be greater than the adhesion of the fixation structure <NUM> to the patient interface <NUM>. To remove the fixation structure <NUM> from the patient's face, a removal force may be applied that overcomes the adhesion between the patient's face and the fixation structure <NUM>. Alternatively, removal mechanisms, such as application of a remover such as water, could reduce the adhesion between the patient's face and the fixation structure <NUM>. Other removers are also contemplated.

<FIG> shows the fixation structure <NUM> with the patient-facing region <NUM> secured to the patient's face. In other words, the patient-facing region <NUM> is facing into the page in <FIG>. As shown, the first edge <NUM> of the fixation structure <NUM> faces toward the nose N, philtrum P, and/or mouth M of the patient. The interface-facing fixation element <NUM>' is adapted to couple with or attach to the attachment structure 216A of the first body 206A of the patient interface <NUM>. In some configurations, when properly aligned with the interface-facing fixation element <NUM>', the bodies 206A, 206B and/or the bridge <NUM> of the patient interface <NUM> may rest above the mouth M and over the philtrum P of the patient.

In some cases it may be desirable to detach the patient interface <NUM>, which is positioned on the patient's face by attachment to the fixation structure <NUM>, while keeping the fixation structure <NUM> on the patient's face. For example, this may be desirable when cleaning and/or replacing the patient interface <NUM>, or securing tubes, including but not limited to, nasogastric or nasojejunal tubes onto the face. However, insufficient securement strength of the fixation structure <NUM> to the patient's face has been found to cause a part of the fixation structure <NUM> to be prone to being lifted away from the face. For example, the fixation structure <NUM> may be lifted away from the patient's face in response to a lifting force (e.g., a force that is substantially normal to the fixation structure <NUM>) being exerted on the interface-facing fixation element <NUM>'. In some configurations, lifting forces may be applied to the fixation structure <NUM> while the patient interface <NUM> is being removed from the fixation structure <NUM>. The securement strength between the fixation structure <NUM> and the patient's face may depend on, for example, the adhesion of the adhesive or sticky material of a patient-facing fixation element <NUM> of the patient-facing region <NUM>. In some cases, the entirety of the patient-facing fixation element <NUM>, and thus the fixation structure <NUM>, can be detached from the face. In some embodiments, when the lifting force is exerted on the interface-facing fixation element <NUM>', the lifting force can be transferred to the patient-facing fixation element <NUM> (which is facing into the page in <FIG>). As illustrated in <FIG>, this transfer of force can cause the first edge <NUM>, or other portions of the body <NUM>, of the fixation structure <NUM> to be lifted from the face.

It has been found that the shape of one or more portions of the fixation structure <NUM> can be a factor in the ability of the fixation structure <NUM> to resist being lifted from the face, for example, upon removal of the patient interface <NUM>. In particular, in the embodiments of the fixation structure <NUM> illustrated in <FIG>, the tapered first edge <NUM> serves to concentrate pressure created by the lifting force exerted on the fixation structure <NUM>, causing it to be vulnerable to being lifted from the face. In an embodiment, the shape of the fixation structure <NUM> can be chosen to determine the pressure distribution profile as the fixation structure <NUM> is removed from the face.

<FIG> show non-limiting examples of embodiments of the fixation structure <NUM> and the interface-facing fixation element <NUM>'. The body <NUM> of the various illustrated embodiments of the fixation structure <NUM> includes a substantially flat or straight embodiment of the first edge <NUM>, rather than a first edge that tapers or narrows in width, as was described in connection with some of the embodiments above. The flat or straight first edge <NUM> allows pressure created by the lifting force to be distributed along the length of the first edge <NUM>. In an embodiment, the corners of the fixation structure <NUM> are substantially rounded. In an embodiment, the corners of the interface-facing fixation element <NUM>' are substantially rounded.

<FIG> shows an example embodiment of the fixation structure <NUM> where the second edge <NUM> is rounded. The third and fourth edges 308A, 308B are at least partially rounded. The interface-facing fixation element <NUM>' extends substantially along the entirety of the interface-facing region <NUM>' of the body <NUM> in a direction defined between the third and fourth edges 308A, 308B. The interface-facing fixation element <NUM>' extends partially along the interface-facing region <NUM>' of the body <NUM> in a direction defined between the first edge <NUM> and the second edge <NUM>. As a result, a portion of the second edge <NUM> may not be immediately adjacent to the interface-facing fixation element <NUM>'.

<FIG> shows an example embodiment of the fixation structure <NUM> where the second edge <NUM> is substantially flat or straight. The third and fourth edges 308A, 308B are substantially rounded. The interface-facing fixation element <NUM>' covers substantially the entirety of the interface-facing region <NUM>' of the body <NUM>. Alternatively, the interface-facing fixation element <NUM>' can cover at least a portion of the interface-facing region <NUM>'. The interface-facing region <NUM>' may provide a border or edge around the interface-facing fixation element <NUM>'. A user (e.g., a nurse or other healthcare provider) may grasp an edge of the fixation structure <NUM> to remove the fixation structure <NUM> from the patient's face. The size of the interface-facing fixation element <NUM>' relative to the size of the fixation structure <NUM> can be configured such that the forces applied to the fixation structure <NUM> during removal of the patient interface <NUM> do not cause the fixation structure <NUM> to be removed from the patient's face.

<FIG> shows an example embodiment of the fixation structure <NUM> in which the first, second, third and fourth edges <NUM>, <NUM>, 308A, 308B are all substantially flat or straight. In an example, the fixation structure <NUM> forms a substantially square or a substantially rectangular shape. In an alternative example, the corners of the fixation structure <NUM> are substantially rounded. The interface-facing fixation element <NUM>' covers substantially the entirety of the interface-facing region <NUM>' of the body <NUM>. Alternatively, the interface-facing fixation element <NUM>' covers at least a portion of the interface-facing region <NUM>'. The interface-facing region <NUM>' may provide a border or edge around the interface-facing fixation element <NUM>'. A user (e.g., a nurse or other healthcare provider) may grasp an edge of the fixation structure <NUM> to remove the fixation structure <NUM> from the patient's face. The size of the interface-facing fixation element <NUM>' relative to the size of the fixation structure <NUM> can be configured such that the forces applied to the fixation structure <NUM> during removal of the patient interface <NUM> do not cause the fixation structure <NUM> to be removed from the patient's face.

<FIG> shows an example embodiment of the fixation structure <NUM> in which the first, second, third and fourth edges <NUM>, <NUM>, 308A, 308B are all substantially flat or straight. The interface-facing fixation element <NUM>' covers only a portion of the interface-facing region <NUM>' of the body <NUM>. In particular, the interface-facing fixation element <NUM>' extends from the first edge <NUM> to a position along the length L of the body <NUM> between the first and second edges <NUM>, <NUM>, and extends from the fourth edge 308B to a position along the width W of the body <NUM> between the third and fourth edges 308A, 308B. As illustrated, in some configurations, the body <NUM> and/or the interface-facing fixation element <NUM>' have a generally square peripheral shape. In some configurations, the interface-facing fixation element <NUM>' may be substantially symmetrical about a plane extending along a diagonal line V. As shown, in some configurations, the diagonal line V extends between the vertex defined by the first and fourth edges <NUM>, 308B and the vertex defined by the second and third edges <NUM>, 308A. The fixation structure <NUM> may then be rotatable by <NUM> degrees to be placed on either cheek of the face. Embodiments of the fixation structure <NUM> with substantially symmetrical construction (e.g., peripheral shape) can enhance convenience and/or can reduce the number of different parts for a healthcare facility to purchase, stock, and maintain.

<FIG> shows an example embodiment of the fixation structure <NUM> in which the first, second, third, and fourth edges <NUM>, <NUM>, 308A, 308B are all substantially flat or straight. The interface-facing fixation element <NUM>' extends along substantially the entirety of the length of the interface-facing region <NUM>' of the body <NUM> between the first and second edges <NUM>, <NUM>. The interface-facing fixation element <NUM>' only extends partially along the width of the interface-facing region <NUM>' of the body <NUM> from the fourth edge 308B to a position between the third and fourth edges 308A, 308B.

<FIG> show non-limiting configurations of the fixation structure <NUM>. <FIG> shows an embodiment of the fixation structure <NUM> having a substantially elliptical shape where all the edges are substantially rounded. The first edge <NUM> tapers slightly along its length but the taper does not end in an extension or knob like the fixation structures shown in <FIG>. The curvature of the first edge <NUM> is such that an aesthetically pleasing shape is imparted while avoiding an undesirably concentrated pressure upon the first edge <NUM> when the lifting force is applied to the fixation structure <NUM>.

<FIG> shows an embodiment of the fixation structure <NUM> having a substantially triangular shape, or a shape similar to the Reuleaux triangle-like shape with rounded edges or a 'guitar pick'-like shape. The shape is substantially symmetrical and can be located on either side of the nose and have the same mechanical characteristics without requiring rotation or re-orientation. Similarly, the first and second edges <NUM>, <NUM> (in this case, either in use being adapted to face toward the patient's nose and/or mouth) are rounded and taper slightly but still avoid undesirably concentrated pressures upon the first and second edges <NUM>, <NUM> when the lifting force is applied to the fixation structure <NUM>.

Other useful shapes for the fixation structure <NUM> are contemplated. In some patients, facial distortion (due to, for example, crying or expression of emotions) or improper handling of the fixation structure <NUM> can cause the fixation structure <NUM> to move over an eye or eyelid, potentially causing momentary duress or irritation for the patient. In some cases, it is desired to form the fixation structure <NUM> such that it is less likely to be pushed into the patient's eye when shear forces, for example, forces that urge the fixation structure <NUM> toward the eye, are exerted on the body <NUM> of the fixation structure <NUM>.

<FIG> shows an interface-facing view of a non-limiting configuration for the fixation structure <NUM>. The illustrated embodiment of the fixation structure <NUM> includes an embodiment of the first edge <NUM> that faces toward the patient's nose or mouth in use and an embodiment of the second edge <NUM> that faces away from the patient's nose or mouth in use. The opposed third and fourth edges 308A, 308B extend between the first and second edges <NUM>, <NUM>. As shown, the third and fourth edges 308A, 308B can include concave curves (e.g., with respect to a longitudinal axis of the fixation structure <NUM>). As illustrated, in some embodiments, the third and fourth edges 308A, 308B include curves that curve or face in opposite directions. The third and fourth edges 308A, 308B project farther from a centerline or center portion of the body <NUM> at parts of the third and fourth edges 308A, 308B that are proximal to the first and second edges <NUM>, <NUM> than at parts of the third and fourth edges 308A, 308B that are distal from the first and second edges <NUM>, <NUM> (e.g. central portions of the third and fourth edges 308A, 308B). Portions of the third and fourth edges 308A, 308B proximal to the second edge <NUM> project farther from the centerline or center portion of the body <NUM> than portions of the third and fourth edges 308A, 308B proximal to the first edge <NUM>. The concave curve of the fourth edge 308B substantially corresponds with a contour of an eye or eyelid, such as the lower eyelid. When an upwards force is exerted on the body <NUM> of the fixation structure <NUM>, such as that shown along force vector F<NUM>, the concave curvature of the fourth edge 308B increases the tendency of the body <NUM> of the fixation structure <NUM> to cup or move around the eye region. This can allow the body <NUM>, for example, to cup the contour of the lower eyelid and/or can decrease the tendency of the body <NUM> to move into or onto the eye or eyelid. As the concave curve is present on both the third and fourth edges 308A, 308B, the fixation structure <NUM> can be rotated by approximately <NUM> degrees to be used on either side of the face while retaining the same properties.

As shown, the interface-facing fixation element <NUM>' is on the interface-facing region <NUM>' of the fixation structure <NUM> and thus, faces away from the patient's face. The interface-facing fixation element <NUM>' is offset from a central portion of the body <NUM>. In the illustrated configuration, the interface-facing fixation element <NUM>' is positioned such that it is closer to the first edge <NUM> than to the second edge <NUM>. In addition, the length L<NUM> of the interface-facing fixation element <NUM>' is less than or equal to the length L<NUM> of the body <NUM> of the fixation structure <NUM>, where L<NUM> is defined as the length between the first and second edges <NUM>, <NUM>. In some configurations, the ratio of the lengths L<NUM>:L<NUM> might be in the range of <NUM> - <NUM>, or in the range of <NUM> - <NUM>, or in the range of <NUM> - <NUM>, or in the range of <NUM> - <NUM>. If the interface-facing fixation element <NUM>' is offset from a central portion of the body <NUM> and the lengths L<NUM> and L<NUM> have such a ratio, the portion of the body <NUM> most distal from the interface-facing fixation element <NUM>', for example, the portion of the body <NUM> nearer to the second edge <NUM>, can provide for a better gripping region when attaching or detaching the fixation structure <NUM> to or from the patient's face.

In some embodiments, the fixation structure <NUM> has an increased area that can act as a bearing portion. For example, the fixation structure <NUM> can include a tab or other protrusion, such as on the first, second, third, and/or fourth edges <NUM>, <NUM>, 308A, 308B. The bearing portion can enable a user (e.g., a nurse) to engage (e.g., push down on) the bearing portion with a finger or instrument. This can aid in disconnecting the fixation structure <NUM> from the tubing (e.g., a nasogastric or nasojejunal tubes) and/or the patient interface. In certain variants, the bearing portion can aid in removing the tubing from the patient. In some embodiments, the bearing portion can help stabilize the fixation structure <NUM> and/or can reduce the disruption of the fixation structure <NUM> on the patient's face.

It should be understood that variations of the fixation structure <NUM> illustrated in <FIG> are contemplated. For example, in some configurations, the concave curve might be present on only one of the third or fourth edges 308A, 308B, such as the edge that, in use, faces toward the patient's eye or eyelid. In some configurations, instead of having a concave curve, one of the third or fourth edges 308A, 308B might only extend farther from the centerline or center portion of the fixation structure <NUM> at a part of the third or fourth edges 308A, 308B proximal to one of the first and second edges <NUM>, <NUM>. In some configurations, portions of the third and fourth edges 308A, 308B proximal to the second edge <NUM> may project at lesser distance, or an approximately equal distance, from the centerline or center portion of the body <NUM> than portions of the third and fourth edges 308A, 308B proximal to the first edge <NUM>. In some configurations, the concave curve may have a more exaggerated shape, including but not limited to a crescent shape. In some configurations, the interface-facing fixation element <NUM>' may be present at or near the center of the fixation structure <NUM> rather than offset from the center. In some configurations, the interface-facing fixation element <NUM>' may occupy most or substantially the entirety of the interface-facing region <NUM>' of the fixation structure <NUM>.

<FIG> shows a view of the fixation structure <NUM> of <FIG> along section C-C. As shown, the body <NUM> of the fixation structure <NUM> has a thickness t<NUM> and the interface-facing fixation element <NUM>' has a thickness t<NUM>. It has been realized that high flexibility or a low Young's modulus is desired for the body <NUM> to allow it to conform to changes in the shape of the face, due to, for example, crying or the expression of emotions. The thickness t<NUM> of the body <NUM> can be, for example, in the range of <NUM> - <NUM>, or <NUM> - <NUM>, or <NUM> - <NUM> In some embodiments, the thickness t<NUM> of the body <NUM> can be, for example, in the range of <NUM> - <NUM> ±<NUM>%, <NUM> - <NUM> ±<NUM>%, <NUM> - <NUM> ±<NUM>%, <NUM> - <NUM> ±<NUM>%, <NUM> - <NUM> ±<NUM>%, <NUM> - <NUM> ±<NUM>%, or approximately <NUM> ±<NUM>%. In some embodiments, the thickness t<NUM> of the body <NUM> is equal to or approximately <NUM>. In some embodiments, the thickness t<NUM> of the body <NUM> may be equal to, about equal to, or less than, the thickness t<NUM> of the interface-facing fixation element <NUM>'. The body <NUM> having a relatively low thickness t<NUM> can improve the overall flexibility of the fixation structure <NUM>. In some embodiments, the body <NUM> includes a material with a low Young's modulus. In certain variants, the entirety of the body <NUM> or substantially the entirety of the body <NUM> includes a material with a low Young's modulus. In some configurations, increasing the flexibility of the body <NUM> may cause the patient-facing region <NUM> of the body <NUM> to not adhere as strongly to the patient's face. Alternatively, increasing the adherence between the patient-facing region <NUM> of the body <NUM> and the patient's face can decrease the flexibility of the body <NUM>. Thus, it is desirable to optimize the adherence between the patient-facing region <NUM> of the body <NUM> and the patient's face, while maintaining flexibility. Different materials may have different effects on flexibility and/or adherence of the body <NUM>.

<FIG> and <FIG> show interface-facing views of additional non-limiting embodiments for the fixation structure <NUM>. The embodiments of <FIG> and <FIG> can include any of the features of the embodiment of <FIG>. For example, as illustrated, the embodiments of <FIG> and <FIG> can include the body <NUM>, the first edge <NUM>, and the second edge <NUM>. The first edge <NUM> can face toward the patient's nose or mouth in use and the second edge <NUM> can face away from the patient's nose or mouth in use. The opposed third and fourth edges 308A, 308B can extend between the first and second edges <NUM>, <NUM>. As shown, the third and fourth edges 308A, 308B can include concave curves (e.g., with respect to a longitudinal axis of the fixation structure <NUM>).

The fixation structure <NUM> can include the interface-facing fixation element <NUM>'. The interface-facing fixation element <NUM>' is on the interface-facing region <NUM>' of the fixation structure <NUM> and thus, faces away from the patient's face. The interface-facing fixation element <NUM>' can be offset from a central portion of the body <NUM>. In the illustrated configuration, the interface-facing fixation element <NUM>' is positioned such that it is closer to the first edge <NUM> than to the second edge <NUM>.

The interface-facing fixation element <NUM>' can include one or more slits. The slits can be in a pattern including alternating columns of shapes of slits. For example, as illustrated, each column can include arched and/or semicircular slits with shapes that face the opposite direction to, and are at least partially offset from, the columns on either side. In some embodiments, portions of the columns of slits overlap in the longitudinal direction of the fixation structure <NUM>.

In some cases, tears, mucus, vomit, or other liquids or liquid-solid mixtures can be present around the fixation structure <NUM> in use. The presence of such materials can reduce the adherence of the patient-facing region <NUM> of the fixation structure <NUM> to the patient. It has been realized that it is desirable to construct the body <NUM> of the fixation structure <NUM> from a material having a relatively low hygroscopicity to reduce the loss of adherence of the patient-facing region <NUM> to the face due to the presence of liquids or liquid-solid mixtures.

<FIG> shows an exemplary non-limiting configuration for the fixation structure <NUM> including the interface-facing fixation element <NUM>'. The interface-facing fixation element <NUM>' includes a hooked pad that forms a 'hook-and-loop' style connection with the one of the attachment structures 216A, 216B of the patient interface <NUM>. The hooked pad includes hooks <NUM>. <FIG> shows a close-up cross-section along dotted line A-A viewed from the first edge <NUM>. As shown, the hooks <NUM> extend toward the fourth edge 308B of the body <NUM> of the fixation structure <NUM>. In some configurations, the hooks <NUM> additionally or alternatively extend toward the third edge 308A of the body <NUM> of the fixation structure <NUM>. In some cases, if the fixation structure <NUM> is used on the face of a patient such as an infant or neonate, the patient is inclined to attempt to remove the fixation structure <NUM> by grasping either the first or second edges <NUM>, <NUM> and pulling the respective edge across the length of the fixation structure <NUM>. It has been realized that the strength of the hook-and-loop securement is anisotropic relative to the orientation of the hooks <NUM>.

In some configurations, and as seen in <FIG>, the hooks <NUM> may be arranged such that they extend toward the second edge <NUM>. (<FIG> is a cross-section of <FIG> along line B-B viewed from the third edge 308A. ) In other configurations the hooks <NUM> may be arranged such that they extend toward the first edge <NUM>, the second edge <NUM>, or the first and second edges <NUM>, <NUM>. If the hooks <NUM> are arranged such that they extend toward the first and/or second edges <NUM>, <NUM>, the strength of the hook-and-loop securement may be such that uncoupling is more greatly resisted when forces are applied along axes substantially parallel to the third and/or fourth edges 308A, 308B than when forces are applied along axes substantially parallel to the first and/or second edges <NUM>, <NUM>. As loops complementary to the hooks <NUM> would be urged substantially toward and/or against the length of the hooks <NUM> when such forces are applied rather than being urged in directions substantially perpendicular to the hooks <NUM>, the forces are more greatly resisted. In some configurations, the hooks <NUM> may extend in multiple directions. In some such configurations, the hooks <NUM> may extend in, for example, substantially perpendicular directions to mitigate the anisotropicity of the strength of the hook-and-loop securement. In some configurations, the angle of the hooks <NUM> can vary to suit different applications. In some configurations, a combination of different angles can be used to determine the strength of securement between the interface-facing fixation element <NUM>' and the patient interface <NUM>. The hooks <NUM> can be positioned at a multiplicity of different angles and/or different directions, to aid with securement strength.

In an embodiment, a combination of at least one of the embodiments of the slits illustrated in <FIG>, and <FIG>, and the configuration of the hooks <NUM> can be used to maximize securement strength and/or flexibility of the interface-facing fixation element <NUM>' with the patient interface <NUM>.

<FIG> shows the use of the fixation structure <NUM> on a skin surface S of the patient's face. The patient-facing region <NUM> includes the patient-facing fixation element <NUM>, which can be constructed from a material that adheres to the skin surface S, for example, a hydrocolloid-based adhesive. As shown, on a microscopic level the skin surface S includes an irregular thickness along the skin surface S and includes a number of bumps and gaps G. Upon application to the skin surface S, the patient-facing fixation element <NUM> initially adheres to only a portion of the skin surface S (see left drawing of <FIG>). Over the course of a period of time t, the adhesive patient-facing fixation element <NUM> flows into the gaps G and increases in adhesion (see right drawing of <FIG>). However, it has been realized that discomfort is experienced when the fixation structure <NUM> is removed from the skin surface S, because, in some cases, hair and part of the stratum corneum of the skin surface S is simultaneously removed. Additionally, in some cases it is difficult to predict the strength of the adhesive at times after the application of the adhesive to the skin surface S.

<FIG> shows the use of an embodiment of the fixation structure <NUM>, wherein the patient-facing fixation element <NUM> is constructed from a silicone-based adhesive. As shown, on a microscopic level, upon application to the skin surface, the patient-facing fixation element <NUM> rapidly flows into the gaps G and quickly reaches a maximum adherence to the skin. Accordingly, the strength of the adhesive at times after the application of the adhesive becomes more predictable. The silicone-based adhesive is less adhesive than the hydrocolloid-based adhesive, and requires less force to remove than the hydrocolloid-based adhesive. Increasing the contact area between the adhesive and the skin can allow sufficient adhesion there between, and reduce the removal of part of the skin surface when the fixation structure <NUM> is removed. If the patient-facing fixation element <NUM> is constructed from a silicone-based adhesive, then the discomfort of removal or detachment of the fixation structure <NUM> from the skin can be reduced.

Unless the context clearly requires otherwise, throughout the description and the claims, the words "comprise", "comprising", and the like, are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense, that is to say, in the sense of "including, but not limited to.

Where, in the foregoing description reference has been made to integers or components having known equivalents thereof, those integers or components are herein incorporated as if individually set forth.

The disclosed methods, apparatus and systems may also be said broadly to comprise the parts, elements and features referred to or indicated in the disclosure, individually or collectively, in any or all combinations of two or more of said parts, elements or features. Further, this disclosure includes combinations of the various features, aspects, methods, properties, characteristics, qualities, attributes, elements, and the like of the various embodiments. For example, any particular feature, aspect, method, property, characteristic, quality, attribute, element, or the like in connection with an embodiment herein can be used in connection with any other embodiment herein.

Language of degree used herein, such as the terms "approximately," "about," "generally," and "substantially," as used herein represent a value, amount or characteristic close to the stated value, amount or characteristic that still performs a desired function or achieves a desired result. For example, the terms "generally parallel" and "substantially parallel" refer to a value, amount or characteristic that can depart from exactly parallel by less than or equal to <NUM> degrees, <NUM> degrees, <NUM> degrees, <NUM> degrees, <NUM> degree, <NUM> degree, or otherwise.

Some embodiments have been described in connection with the accompanying figures. The figures are drawn to scale, but such scale should not be limiting. Dimensions and proportions other than what are shown are contemplated and are within the scope of this disclosure. Distances, angles, shapes, etc. are merely illustrative and do not necessarily bear an exact relationship to actual dimensions and layout of the devices illustrated. Components can be added, removed, and/or rearranged.

Claim 1:
A fixation structure (<NUM>) for securing a patient interface (<NUM>) on a patient's face, the fixation structure (<NUM>) comprising:
a body (<NUM>);
wherein a first side of the body (<NUM>) facing away from the patient's face and toward the patient interface (<NUM>) comprises a fixation element (<NUM>'), the fixation element attachable to a complementary fastener of an attachment structure (216A, 216B) of the patient interface (<NUM>); and
characterized in that the fixation element (<NUM>') has a pattern of slits which facilitate flexibility to the fixation element (<NUM>'),
wherein the pattern of slits includes alternating columns of shapes of slits.