Facial mask with custom-manufactured cushion element, and associated method

Disclosed is a method of forming at least a portion of a mask (4) that is structured to engage at least a portion of the face of a patient (52). The method can be generally stated as including employing at least a portion of a data set (74) that is stored on a machine-readable storage medium (72) and that is representative of the shape of at least a portion of the face in generating a configuration for an cushion element (24) of the mask. The cushion element is structured to extend from a support (20) of the mask and to have an engagement end (50) bopposite the support that corresponds with the shape of the at least portion of the face. The method can be generally stated as further including subjecting a workpiece (78) to a formation operation to cause at least a portion of the workpiece to be formed into the cushion element having the engagement end.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to a mask that is structured to deliver a flow of breathing gas to a patient, and, more particularly, to such a mask having a custom-manufactured cushion that corresponds with the shape of the face of the patient, and an associated method.

2. Description of the Related Art

There are numerous situations where it is necessary or desirable to deliver a flow of breathable gas non-invasively to the airway of a patient, i.e., without intubating the patient or surgically inserting a tracheal tube in their esophagus. For example, it is known to ventilate a patient using a technique known as non-invasive ventilation. It is also known to deliver continuous positive airway pressure (CPAP) or variable airway pressure, which varies with the patient's respiratory cycle, to treat a medical disorder such as sleep apnea syndrome, in particular, obstructive sleep apnea (OSA), or congestive heart failure.

Non-invasive ventilation and pressure support therapies involve the placement of a respiratory patient interface device including a patient interface that is typically secured on the face of a patient by a headgear assembly. The patient interface may be, without limitation, a nasal mask that covers the patient's nose, a nasal cushion having nasal prongs that are received within the patient's nares, a nasal/oral mask that covers the nose and mouth, or full face mask that covers the patient's face. It is known to maintain such devices on the face of a wearer by a headgear having one or more straps adapted to fit over/around the patient's head. Because such respiratory patient interface devices are typically worn for an extended period of time, it is important for the headgear to maintain the patient interface in a desired position while doing so in a manner that is comfortable to the patient.

Such respiratory patient interface devices typically must also form a reliable and generally fluid-tight seal with the face of the patient in the vicinity of the airways in order to ensure that the flow of air is delivered to the airways and does not leak from around the patient interface. Due to the great variability of the facial features of the various patients who require such therapy, reliable seals have sometimes been difficult to provide and/or maintain. While such patient interfaces have typically been available in various sizes, it is understood that any mask of a particular size will have limits with respect to its ability to accommodate facial variability. It thus would be desirable to provide an improved mask that meets these and other limitations known in the relevant art.

SUMMARY OF THE INVENTION

In certain embodiments, the general nature of the invention can be stated as including an improved method of forming at least a portion of a mask that is structured to deliver a flow of breathing gas to the airways of a patient and that is structured to engage at least a portion of the face of the patient in the vicinity of the airways. The method can be generally stated as including employing at least a portion of a data set that is stored on a machine-readable storage medium and that is representative of the shape of at least a portion of the face in generating a configuration for an cushion element of the mask. The cushion element is structured to extend from a support of the mask and to have an engagement end opposite the support that corresponds with the shape of the at least portion of the face. The method can be generally stated as further including subjecting a workpiece to a formation operation to cause at least a portion of the workpiece to be formed into the cushion element having the engagement end.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENT

As used herein, the word “unitary” means a component is created as a single piece or unit. That is, a component that includes pieces that are created separately and then coupled together as a unit is not a “unitary” component or body. As employed herein, the statement that two or more parts or components “engage” one another shall mean that the parts exert a force against one another either directly or through one or more intermediate parts or components.

An improved mask4in accordance with the present invention is disclosed generally inFIG. 1. As can be generally understood, mask4will typically be connected with some type of headgear (not expressly depicted herein) to mount mask4to a patient in order to provide a flow of breathing gas to the patient for respiratory therapy. While the depicted exemplary embodiment of mask4is of a nasal/oral mask that covers the nose and mouth of a patient, it is noted that the advantageous features of mask4that are set forth herein can be employed in any alternative type of patient interface, such as those set forth above, without departing from the present concept.

As will be set forth in greater detail below, mask4advantageously includes a custom-manufactured cushion element that has been custom-formed according to a computer-generated configuration which corresponds with the shape of a patient's face. Mask4thus maintains a substantially fluid tight seal with the face of the patient without the need to engage mask4against the face with a great deal of force, which makes mask4relatively more comfortable for the patient to wear as compared with previously known masks.

As can be seen inFIG. 1, mask4can be said to include a frame6upon which is pivotably disposed an elbow8that is connected with a CPAP machine or other source of breathing gas for the provision of respiratory therapy. Mask4further includes a forehead brace12that is connected with frame6and that is engageable with the forehead of the patient. Mask4further includes a flexible and collapsible bellows14mounted to frame6and further includes a patient interface18mounted to bellows14. Elbow8, bellows14, and patient interface18are in fluid communication with one another and provide a flow of breathing gas to the patient for respiratory therapy. Bellows14and patient interface18are connected together in any of a variety of fashions that can include adhering, mechanically connecting, co-forming, and the like without limitation.

As suggested above, patient interface18is advantageously designed to provide a substantially fluid-tight connection with a patient in order to reliably provide the flow of breathing gases to the patient through the patient's airways. Patient interface18itself is depicted in an exploded fashion inFIGS. 2 and 3. It can be seen that patient interface18can be said to include a support in the form of a face plate20, and it further includes a cushion element24and a seal apparatus26disposed on face plate20. Patient interface18is assembled by receiving a portion of cushion element24between a portion of seal apparatus26and a portion of face plate20, and seal apparatus26is then mounted to face plate20. It is noted, however, that in other embodiments of patient interface18, the various components thereof can be of different configurations and can be connected together in different fashions without departing from the present concept.

Seal apparatus26in the depicted exemplary embodiment includes a relatively rigid attachment feature30and a relatively flexible and resilient sealing flap32that are connected together. In the exemplary embodiment depicted herein, attachment feature30and sealing flap32are co-formed but could be connected together in other fashions without departing from the present concept. Attachment feature30has a plurality of receptacles42formed therein for connection with face plate20.

More specifically, face plate20can be said to include a plate member36and plurality of protruding tabs38. When a portion of cushion element24is received against a portion of seal apparatus26, tabs38are received in receptacles42to cause face plate20and seal apparatus26to become connected together and to have at least a portion of cushion element24interposed therebetween. Patient interface18can then be connected with bellows14if such connection has not already been made between bellows14and face plate20.

As can further be understood fromFIGS. 2 and 3, cushion element24can be said to include a cushion body44that extends in a direction generally away from face plate20and to further include a cushion lip46that extends in a transverse direction. That is, and as is depicted generally inFIG. 4, whereas cushion body44extends in a direction generally away from face plate20and toward the face of a patient52, cushion lip46extends in a direction generally parallel with plate member36of face plate20and is generally the portion of cushion element24that is interposed between face plate20and seal apparatus26and which retains cushion element24in position on patient interface18.

Cushion element24can also be said to include an engagement end50that is depicted inFIGS. 3 and 4as being situated on and end of cushion body44opposite cushion lip46. Cushion element24and especially engagement end50are advantageously custom manufactured according to a computer-generated configuration in order to cause engagement end50to be formed in such a fashion that is corresponds with a portion of the face of patient52. Such custom manufacturing provides improved fit of mask4on patient52with correspondingly improved comfort and reliability of the seal between mask4and patient52. As will be set forth in greater detail below, cushion element24is custom-manufactured to enable patient interface18to have a custom fit with the face of patient52along an engagement path, such as is indicated with an exemplary dashed line shown generally at the numeral56inFIG. 4. It is noted, however, that in patient interface18depicted generally herein, the free end of sealing flap32opposite attachment feature30actually contacts patient52along engagement path56and is generally interposed between engagement end50and patient52when mask4is installed on patient52.

With regard to the custom manufacturing of cushion element24in accordance with the present invention, it can be generally stated that a computerized device employs the shape of the face of patient52to generate a custom configuration for cushion element24that will enable patient interface18to have a custom fit with the face of patient52. Variable machinery in employed to manufacture cushion element24in accordance with the computer-generated configuration.

More particularly,FIG. 5can be said to generally depict a computer54having a processor apparatus62, an input apparatus64that provides input signals to processor apparatus62, and an output apparatus68that receives output signals from processor apparatus62. Input apparatus64can include any of a variety of input devices such as scanners, keyboards, and the like, and output apparatus68can likewise include any of a variety of output devices such as displays, actuators, and the like, all without limitation. Processor apparatus62can be said to generally include a processor70and a memory72. Processor70can be any of a wide variety of processors, such as a microprocessor or other type of processor. Memory72can be any of a wide variety of machine readable storage media such as RAM, ROM, EPROM, EEPROM, FLASH, and the like without limitation.

Memory72has stored therein a data set74that is representative of at least a portion of the face of patient52, and it further has stored therein one or more routines that are indicated generally at the numeral76. Data set74can be obtained in any of a variety of fashions such as by scanning the face of patient52, by resolution of multiple photographs of the face of patient52, and the like without limitation. Data set74can be in any of a variety of forms such as a plurality of discrete data points, one or more equations that characterize contours of the face, and the like in any combination without limitation.

One of routines76employs at least a portion of data set74to generate a configuration of cushion element24that will enable cushion element24to be connected with face plate20and seal apparatus26in the vicinity of cushion lip46, and to also correspond with the face of patient52along engagement end50. As such, data set74is employed in generating the configuration of engagement end50in order to cause it to correspond with the shape of patient52.

Additionally, however, it is likely desirable to have a plurality of face plates from which face plate20is selected. That is, due to the variability of the shapes, sizes, and contours of faces among the population of various patients, it likely will be desirable to provide more than one face plate in order to enable the custom-manufactured cushion element24to be configured to have a relatively more customized fit than would be possible with only a single face plate that is configured to work with an entire population. As such, routine76will not only generate a configuration for engagement end50of cushion element24, it will also select from a plurality of available face plates the particular face plate20that will provide the best fit for patient52. In this regard, routine76may already include data that is representative of the configurations of the available face plates or, even more desirably, will have access to data that is representative of the various face plates that are available and which potentially may change depending upon future availability or non-availability of the various face plates from which face plate20is selected.

It thus can be understood that routine76employs at least a portion of data set74, which is representative of the face of patient52, to custom generate a configuration for cushion element24that will enable its engagement end50to conform with the face of patient52and to enable patient interface18to have a substantially fluid-tight seal with the face of patient52. Routine76will also, as appropriate, select from a plurality of face plates the particular face plate20that is most appropriate to the face of patient52and thus will generate the configuration that not only provides the aforementioned engagement end50but that also provides cushion lip46and other appropriate portions of cushion element24that enable cushion element24to cooperate with the selected face plate20. That is, routine76is executed by processor70to cause the outputting of the custom-generated configuration for cushion element24, and the configuration is then employed to custom manufacture cushion element24.

Cushion element24can be manufactured out of any of a wide variety of materials, including metallic and/or non-metallic materials without limitation. In the exemplary embodiment depicted herein, cushion element24is formed from a nickel-titanium alloy and further receives a coating of an elastomeric resilient material such as a silicone-based rubber. As is generally understood, nickel-titanium alloys possess super-elastic properties and other properties which can be manifested in a temperature-dependent manner. That is, depending upon temperature, nickel-titanium alloys can have elastic spring characteristics that are linear and/or non-linear. They also can have a shape memory feature. Cushion element24can take advantage of such deflection and other characteristics in order to provide a desirable fit with the face of patient52.

In the exemplary embodiment herein, cushion element24is formed from a workpiece78that is depicted generally inFIG. 6as being a flat sheet of mesh formed from fibers of nickel-titanium alloy.FIG. 6also depicts in dashed lines the configuration of cushion element24superimposed thereon for purposes of illustration.

More particularly, the present invention employs a variable mold apparatus82(FIGS. 7 and 8) that is varied according to the computer-generated configuration of cushion element24in order to form cushion element24from workpiece78. The exemplary variable mold apparatus72can be said to include a first mold portion84and a second mold portion86that are each variable according to the configuration and which are compressively engageable with one another to form patient interface18out of workpiece78. More particularly, first mold portion84includes a first base member88upon which are disposed a plurality of movable mold elements90. Second mold portion86likewise includes a second base member92upon which are disposed a plurality of movable mold elements94. Based upon the configuration for cushion element24that has been generated by computer58, movable mold elements90and94are positioned on first and second base members88and92, respectively, such that when workpiece78is heated and compressively engaged between first and second mold elements84and86, workpiece78will be deformed into a shape from which cushion element24can be cut.

In the depicted exemplary embodiment ofFIGS. 7-9, movable mold elements90and94are translatable on first and second base members88and92such that the ends of movable mold elements90and94are together situated generally along contours that match the shape of the configuration which cushion element24is ultimately desired to have. More particularly, and with regard to movable mold elements90of first mold portion84which are depicted inFIG. 9as being superimposed over workpiece78, each movable mold element90can be said to be at a particular location on first mold portion84. For example, movable mold element90A is at one location, which is different from the location of movable mold element90B, and both of which are at a different location than movable mold element90C.

Moreover, the configuration of cushion element24generated by computer58from data set74has a set of positions in three-dimensional space at each of the aforementioned locations of first mold portion84. Examples of such positions are the positions80A,80B, and80C. The various movable mold portions90are thus translated with respect to first base member88, as appropriate, along an axis that extends into the plane of the page ofFIG. 9to position the mold elements90that are at the various locations (such as at the locations90A,90B, and90C) such that the ends of such movable mold elements90that will engage workpiece78generally follow the configuration generated by computer58. Movable mold elements94of second mold portion86are similarly positioned such that the ends of movable mold elements94together form a cooperative mold portion that is cooperative with first mold portion84.

That is, and as can be understood fromFIGS. 7 and 8, movable mold elements90and94are positioned with respect to first and second base members88and92such that the ends of movable mold elements90and94that will contact workpiece78are collectively of a contour which, after deformation of workpiece78, will result in workpiece78taking the shape of cushion element24. While movable mold elements90and94are depicted herein as being translatable with respect to first and second base members88and92, it is understood that movable mold elements90and94in other embodiments could be otherwise movable, such as by rotation or otherwise, to be positioned as set forth above in a such fashion that will result in the formation of cushion element24.

Variable mold apparatus82is depicted herein in a schematic fashion in order to illustrate its ability to be custom figured in accordance with the configuration generated by computer58, and it is understood that movable mold elements90and94can be positioned in any of a variety of fashions. For example, movable mold elements90and94can be positioned by actuators, such as mechanical or hydraulic actuators, that are a part of output apparatus68and which are operated according to the configuration generated by computer58. Alternatively, movable mold elements90and94could be positioned manually in accordance with data values that may be output by computer58, with a separate data value corresponding with each of the locations of movable mold elements90and94, by way of example. Other fashions of positioning movable mold elements90and94in accordance with the generated configuration will be apparent. After such positioning, movable mold elements90and94may need to be locked in position with respect to first and second base members88and92, as appropriate.

In the exemplary embodiment of the method depicted herein, first and second mold portions84and86are first configured with their movable mold elements90and94positioned according to the configuration generated by computer58. Workpiece78is then heated and is situated between first and second mold portions84and86, which are then pressed together as is indicated generally with a pair of arrows96A and96B for purposes of illustration inFIG. 8. It is understood that one of first and second mold elements84and86likely will remain stationary and the other pushed generally toward it into compressive engagement therewith.

During such compressive engagement between movable mold elements90and movable mold elements94, individual corresponding pairs of movable mold elements90and94can be said to form cooperative pairs98of movable mold elements that are generally engaged with one another while having a portion of workpiece78compressively engaged therebetween. That is, each of the movable mold elements90, as are indicated generally inFIG. 9, are situated at a location (as at the locations90A,90B, and90C) on first mold portion84, and each correspond with a correspondingly positioned movable mold element94on second mold portion86(which is not expressly depicted inFIG. 9but would be situated underneath first mold portion84). The movable mold element90at the location90A together with the movable mold element94that is at the same location on second mold portion86form a cooperative pair98of movable mold elements.

The cooperative pairs98of movable mold elements at each location thus compressively engage and deform workpiece78at the various locations to result in workpiece78being deformed as is indicated generally inFIG. 10. That is,FIG. 10depicts the deformed workpiece78having cushion element24formed thereon. Cushion element24can then be cut from a remaining portion of workpiece78and coated with a resilient material, such as a silicone-based elastomer, to result in cushion element24as is depicted generally inFIGS. 11 and 12. Cushion element24can then be incorporated into patient interface18and mask4as indicated above.

While the exemplary method is depicted herein as including configuring first and second mold portions84and86prior to engaging workpiece78, it is understood that in other embodiments workpiece78potentially can be compressively engaged between first and second mold portions84and86, followed by movement of cooperative pairs78of movable mold elements in order to deform workpiece78. In this regard, it is understood that nickel-titanium alloys can be difficult to work, and it is also understood that metallic materials undergoing plastic deformation experience elastic springback that can vary depending upon the properties of the materials out of which workpiece78is manufactured. Such properties would be represented by variables within routine76in order that the configuration that is generated by computer58will result in cushion element24. Thus, since workpiece78will experience at least a certain degree of elastic springback once the compressive forces from first and second mold portions84and86are removed, the configuration that is generated by computer58will typically not be exactly that of cushion element24but will be the configuration of variable mold apparatus82which will result in cushion element24after the formation process set forth above. Thus, while the “configuration” that is generated by computer58is described herein as being that of cushion element24, it is noted that such “configuration” can variously refer without limitation either specifically to cushion element24or to the positioning of the various elements of variable mold apparatus84from which cushion element24is formed.

FIG. 15depicts an exemplary flowchart which illustrates certain aspects of an improved method in accordance with the disclosed and claimed concept. Processing can be said to begin by employing, as at110, data set74, which is representative of the face patient52, in order to generate a configuration for cushion element24or that will result in cushion element24when subjected to the formation operation described herein. While data set74is assumed herein to already exist, its generation may be considered to be a step that occurs prior to step110. Movable mold elements90and94of variable mold apparatus82are then positioned, as at116, in accordance with the configuration generated by computer58. Workpiece78is heated, as at122, and is compressively engaged, as at128, between first and second mold portions84and86.

After the deformed workpiece78has been removed from variable mold apparatus82, cushion element24is cut, as at134, from a remaining portion of workpiece78. Cushion element24can then be coated, as at140, with a silicone coating or other coating, if desired. Cushion element24can then be assembled into mask4, as at148.

The improved method described herein and the improved custom-manufactured cushion element24that is formed from the improved method advantageously provide an improved fit and improved comfort for patient52. Other benefits will be apparent to those of ordinary skill in the relevant art.