Abstract:
An artificial airway device used to facilitate lung ventilation in an unconscious patient, and methods for using and inserting an artificial airway device. The device includes a curved but flexible airway tube and a mask portion. A mask opening portion is shaped so as to fit closely adjacent and closely over the patient&#39;s laryngeal opening. A seating tip includes a series of thin, flexible fins or gills which project from a finger portion extending from the mask opening portion. The fins or gills seat against the pharyngeal side of the cricoid, just above the esophagus. The mask portion can be anchored against a relatively hard surface without causing damage to delicate tissue in the esophagus. The seating tip provides a reference for the person inserting the artificial airway device which ensures that the mask portion is properly in place and adequately anchored. The artificial airway also includes an inflatable cuff used to anchor the artificial airway in place.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to artificial airway devices used to facilitate lung ventilation in unconscious patients, and more specifically to devices designed for placement above the laryngeal opening of the patient in order to prevent airway obstruction and to permit either spontaneous or controlled ventilation. 
     2. Description of Related Art 
     To maintain open the airway of an unconscious patient under general anesthesia, it is common practice to use an endotracheal tube, which is a flexible tube of rubber or plastic which is inserted down through the trachea. Prior art endotracheal tubes frequently include an inflatable cuff disposed symmetrically around a distal end of the tube, which distal end is inserted into the trachea. The inflatable cuff is used to seal and secure the endotracheal tube in place. 
     Typically, the endotracheal tube is introduced through mouth or nose and the larynx into the trachea or windpipe, and then the cuff is inflated through a small auxiliary tube in order to form a seal against the wall of the trachea. Introduction of the endotracheal tube into a patient is a skilled operation normally requiring use of a laryngoscope to guide the tube through the larynx, past the vocal cords and into the trachea. Intubation using an endotracheal tube is difficult or even impossible in some patients. Moreover, there is a significant risk of damage to soft tissues or to the larynx when using an endotracheal tube. Likewise, there is a risk of accidental, but highly undesirable, intubation of the esophagus or of the right or left main bronchus when using an endotracheal tube. 
     Alternatively, oro- or naso-pharyngeal airway devices may be used to maintain open the airway of a patient under general anesthesia. An oro- or naso-pharyngeal airway is a flexible tube extending from the mouth (oro-pharyngeal airway) or nose (naso-pharyngeal airway) into the patient&#39;s pharynx but not into the patient&#39;s larynx. An oro- or naso-pharyngeal airway is normally used in conjunction with a face mask over the patient&#39;s mouth and/or nose, unlike an endotracheal tube, which normally is not used with a mask. While preventing obstruction of the airway by the tongue, an oro- or naso-pharyngeal airway device cannot be used conveniently for controlled ventilation of the patient and does not prevent inhalation of extraneous matter (i.e., aspiration). For these and other reasons this type of device is less desirable in many applications. 
     Prior art artificial airways (see for example, U.S. Pat. Nos. 4,509,514; 4,995,388; 5,241,956; 5,249,571; 5,282,464; 5,297,547; 5,305,743; 5,355,879; 5,584,290; 5,632,271 and 5,682,880 to Archibald I. J. Brain—collectively, the “Brain patents”) use a curved tube and a laryngeal mask portion at one end of the tube. The mask portion includes a flexible annular inflatable collar which surrounds a hollow interior space of the mask portion. The mask portion is pre-formed with a roughly elliptical shape which is purported to be capable of conforming to, and fitting within, the space behind the larynx to form a seal around the circumference of the laryngeal inlet without penetrating into the interior of the larynx. The curved tube opens into the mask portion and provides an airway with the axis of the tube substantially aligned with the length of the elliptical formation of the mask portion. 
     In the Brain patents, the curved tube opens into a lumen of the mask through an aperture which is provided with flexible cross-bars to prevent the aperture from being obstructed by the epiglottis, while permitting passage of a second smaller tube, such as an endotracheal or endobronchial tube, a suction catheter, or an inspection tube such as a fiber-optic broncho- or laryngoscope. 
     SUMMARY OF THE INVENTION 
     The present invention is an artificial airway device which is designed to overcome certain shortcomings which have been discovered with the use, in practice, of artificial airways of the prior art. The present invention is also designed to be inexpensive, to be easy to insert without causing damage to the patient and without the need for a laryngoscope or other inspection instruments, and to provide an effective airway which is not readily blocked or obstructed during use. 
     The present invention is inexpensive to use and easy to insert and therefore appropriate for Emergency Medical Service (EMS) use. This provides advantages over the prior art; the airway devices as shown in the Brain patents can have a tendency for the uninflated collar to pleat or fold during insertion, which results in incomplete expansion of the collar during inflation. Incomplete inflation results in leakage, which prevents effective use of the artificial airway in the manner in which it is intended to be used. Furthermore, the inflatable collars often do not conform well to the airway, also resulting in leakage. In addition, it is often difficult for the individual inserting the artificial airways shown in the Brain patents to determine whether the inflatable collar is completely inflated. In order to overcome these inflation and leakage problems, artificial airways with inflatable collars are often overinflated by the individual inserting the airway to pressures sufficiently high that they can cause damage to the soft tissue against which the inflatable collar seals. 
     Another difficulty with prior art artificial airways using an inflatable collar, as in the Brain patents, is that it is often difficult for the individual inserting the airway to determine when the airway mask is properly in place over the larynx. This uncertainty of proper placement makes complete sealing more difficult, and also complicates insertion of the airway into the patient. Because of this difficulty, the artificial airways of the Brain patents are generally not suitable for EMS use. Additionally, artificial airways with inflatable collars, because they must be completely inflated to properly seal, require a large number of sizes to accommodate the different sizes of airways of the patients to which they are administered. Endotracheal tubes and oro- or naso-pharyngeal airways are also generally not suitable for use by EMS personnel. 
     Prior art artificial airways can also cause difficulties in ensuring that the artificial airway, or parts of the airway, does not accidentally enter the esophagus during insertion. Entry into the esophagus can cause damage to delicate tissues, which is undesirable and can cause severe complications for the patient. Furthermore, the prior art artificial airways often do not have adequate mechanisms to securely anchor the device in place after insertion, a feature which is important, particularly in EMS use. 
     The present invention is an artificial airway device used to facilitate lung ventilation in an unconscious patient and methods for using and inserting an artificial airway device, all of which overcome the shortcomings of prior art artificial airway devices. The device of the present invention includes a curved but flexible airway tube and a mask portion, which mask portion includes a mask opening portion and a seating tip. The mask portion is attached to the airway tube at a distal end of the airway tube. The mask opening portion is shaped so as to fit closely adjacent and closely over the patient&#39;s laryngeal opening without entering into the larynx and without requiring the mask opening portion to be sealed against the larynx or laryngeal opening. The seating tip includes a series of thin, flexible fins or gills which project from a relatively rigid projecting finger extending axially from, and preferably formed integrally with, the mask opening portion. On one side of the seating tip, at least some of the fins or gills can have an undulating shape across their width, in one embodiment of the invention, to compensate for flexing or expansion of the seating tip as it seats in position. The fins or gills seat against the pharyngeal side of the cricoid, just above the esophagus. In this way, the mask can be properly located above the laryngeal opening, and can be anchored against a relatively hard surface without causing damage to delicate tissue in the esophagus or delicate tissue in or around the larynx or laryngeal opening. The seating tip, and its placement against the pharyngeal side of the cricoid, therefore provides a reference for the person inserting the artificial airway device which ensures that the mask opening portion is properly in place and adequately anchored or seated in place. The interaction between the seating tip and the pharyngeal side of the cricoid helps ensure that the individual inserting the airway accurately positions the mask opening portion, and therefore the connection to the airway tube, over the patient&#39;s laryngeal opening. The pharyngeal side of the cricoid also serves as a relatively rigid anchoring area for the mask portion, thereby ensuring that the mask opening portion remains in position closely adjacent and closely surrounding the laryngeal opening. The mask opening portion is shaped to conform to the space around the laryngeal opening, thereby providing an airway to the laryngeal opening without having to form a seal around the circumference of the laryngeal opening and without penetrating into the interior of the larynx or the entrance to the esophagus. 
     The shape of the mask opening portion ensures that it closely approximates the shape of the laryngeal opening. Because the artificial airway of the present device is not required to seal against the laryngeal opening, and because the seating tip of the present invention is designed to anchor or seat against the relatively rigid pharyngeal side of the cricoid, only a few artificial airway sizes are needed to accommodate a wide range of patient airway sizes, therefore reducing the number of artificial airway sizes needed. This feature of the present invention also reduces costs, and makes the present invention more amenable to EMS use, since fewer devices, and less storage space, is needed by the EMS crew. In addition, the seating of the seating tip against the pharyngeal side of the cricoid provides a good tactile indication when the mask opening portion is properly in place in the airway, thereby enhancing the ease and accuracy of insertion of the artificial airway in the patient. 
     The artificial airway of the present invention is designed to be easy and convenient to insert in the majority of patients. The artificial airway may also be inexpensively manufactured in quantity, thereby allowing it to be disposable. As a result, the artificial airway of the present invention may be more readily used in EMS or other non-hospital applications, as well as in surgical applications. When the seating tip of the mask portion reaches the pharyngeal side of the cricoid above the esophagus, a definite end-point can be felt by the individual inserting the artificial airway, indicating that the mask portion is correctly placed. The mask portion does not enter the larynx or trachea, and the seating tip does not enter the esophagus, so the risk of damage to these delicate structures is avoided. 
     Likewise, the risk of accidental entry of the mask portion into the esophagus or one of the main bronchi is also avoided with use of the artificial airway of the present invention. Once in place, the artificial airway is generally used to allow the lungs to be ventilated by positive pressure. Alternatively, the patient may be permitted to breathe spontaneously after insertion of the artificial airway of the present invention. 
     The seating tip of the present invention may provide some degree of blockage so as to prevent gastric reflux from the stomach and aspiration into the patient&#39;s airway, making the artificial airway of the present invention more adaptable to emergency and EMS use, as well as adaptable to a larger variety of surgical applications than prior art artificial airways. 
     The present invention also includes an inflatable cuff used to anchor the artificial airway in place using the patient&#39;s tongue and oro-pharynx behind the uvula. This inflatable cuff is preferably offset relative to the airway tube. The offset of the inflatable cuff helps to ensure that the mask opening portion is held closely near the laryngeal opening, thereby allowing more effective operation of the artificial airway device. The inflatable cuff may be deflated so that the artificial airway device may be more easily inserted into the patient, and thereafter inflated to anchor the artificial airway device in place. 
     In the method of insertion of an artificial airway according to the present invention, the inflatable cuff is first deflated. The artificial airway is lubricated, and then inserted down the patient&#39;s oral cavity. The seating tip of the artificial airway is fed along the hard and soft palate, the back of the oropharynx, and into the cricopharynx adjacent the cricoid. When resistance is felt due to interaction between the seating tip and the cricoid, insertion is halted. The artificial airway is then pulled back slightly, to lift the epiglottis away from the mask opening and so that the inflatable cuff is just behind the uvula. The inflatable cuff is then inflated. The patient may then be ventilated. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Other objects and advantages of the invention will be apparent from the specification and claims, when considered in connection with the attached sheets of drawings, illustrating different forms of the invention, wherein like characters represent like parts and in which: 
     FIG. 1 is a perspective view of one embodiment of the artificial airway device of the present invention. 
     FIG. 2 is a side elevation view of the mask portion used with the embodiment of FIG.  1 . 
     FIG. 3 is perspective view of the embodiment of FIG.  2 . 
     FIG. 4 is a rear elevation view of a second embodiment of a mask portion which may be used with the embodiment of FIG.  1 . 
     FIG. 5 is side elevation view of the embodiment of FIG.  2 . 
     FIG. 6 is a side elevation view of a third embodiment of a mask portion used with airway device of FIG.  1 . 
     FIG. 7 is a partially cross-sectional view of the artificial airway device of the present invention, as inserted in the airway of a patient, prior to retraction and inflation. 
     FIG. 8 is a partially cross-sectional view of the artificial airway device of the present invention, as inserted in the airway of a patient, after retraction and inflation. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1 is a perspective view of one embodiment of the artificial airway of the present invention. In the embodiment of FIG. 1, a mask portion  100  is connected to a partially curved airway tube  200  which includes a connection end  300 . Connection end  300  may be connected to any known device or mechanism for providing artificial or spontaneous ventilation of a patient and/or for providing oxygen, air, anesthesia or other gases to the respiratory system of the patient. An inflation fluid supply unit  400  with a fluid connector  403  is also shown in FIG.  1 . 
     In the embodiment shown in FIG. 1, the mask portion  100  includes a opening portion  110  and a seating tip  120  extending axially outwardly from the mask opening portion  110 . The mask portion  100  is preferably integrally formed in one piece, and includes an opening  101  which securely receives a distal end  201  of the airway tube  200 . 
     The airway tube  200  is assembled into the opening  101  and fixed to the mask portion  100 , using any appropriate attachment technique or mechanism. In the preferred embodiment of FIG. 1, the airway tube  200  is made of a material which is sufficiently flexible to permit it to deform so as to fit down the patient&#39;s airway (see FIGS.  7  and  8 ), but is also sufficiently stiff to permit the airway tube  200  and the mask portion  100  to be accurately positioned manually in the patient P. Polyvinyl chloride (PVC), or any other known inexpensive, durable and partially flexible material may be used as the material from which the airway tube  200  is made. 
     The airway tube  200  includes a large central bore  204  through which various gases (e.g., anesthesia, oxygen, air) can be administered to the patient, if and when desired. In addition, the airway tube  200  includes a small conduit  202  in the tube wall. In the embodiment shown in FIG. 1, the small conduit  202  would be located on the underside (shown on the right in FIG. 1) of the airway tube  200 . The small conduit  202  is used to transmit a fluid into and out of the interior of the inflatable cuff  800  to inflate and deflate the inflatable cuff  800 , and is connected to the fluid supply unit  400 . 
     The inflatable cuff  800 , which is in the form of a fluid-expandable pillow or cuff, is mounted on the shaft of the airway tube  200 , in a location on the tube  200  where it is adjacent the tongue T and behind the uvula U of the patient P in the pharynx when the mask opening portion  110  of the present invention is in place over the larynx L (see FIGS.  7  and  8 ). As shown in FIG. 1, the inflatable cuff  800  is offset relative to the airway tube  200 , such that one side  801  of the inflatable cuff  800  extends a greater distance away from the airway tube  200  than the other side  802 . The side  801  which extends a greater distance from the airway tube  200  is preferably located opposite the mask opening  111  of the mask opening portion  110 . As a result, and as may be seen in FIG. 8, the mask opening portion  110  is located closely adjacent the laryngeal opening over the larynx L of the patient P when the artificial airway of the present invention is in place and the seating tip  120  is seated against the pharyngeal side of the cricoid C. During insertion of the artificial airway of the present invention into the airway of the patient P, the inflatable cuff  800  is in a contracted position (shown in FIG.  7 ). An opening  203  through the wall of airway tube  200  leads from the small conduit  202  to the interior of the inflatable cuff  800 . Once the artificial airway of the present invention is in place with the mask opening portion  110  over the laryngeal opening of the larynx L, fluid may be applied to connector  403 , thereby expanding the inflatable cuff  800  to the condition shown in FIG.  1 . The inflatable cuff  800 , in the expanded condition, contacts the tongue T of the patient P and the opposed portion of the oro-pharynx behind the uvula U, thereby anchoring the artificial airway of the present invention in place within the airway of the patient P. 
     The mask portion  100  includes an upper or proximal mask opening portion  110  and a lower or distal seating tip  120 . The mask opening portion  110  includes a mask opening  111  which opens into the distal end  201  of the large conduit  204  in the airway tube  200 , thereby allowing gases to be delivered to, and drawn from, the patient&#39;s respiratory system. The mask opening portion  110  has a shape  112  surrounding the mask opening  111  which is designed to approximate the shape of the laryngeal opening of the larynx L, thereby covering the laryngeal opening without sealing against the tissues surrounding the laryngeal opening. In this way, the mask opening portion  110  provides virtually complete coverage of the laryngeal opening of the larynx L, helping to prevent the incursion or ingress of anything into the patient&#39;s airway other than the gases delivered through the large conduit  204  of the airway tube  200 . 
     The seating tip  120  includes a relatively rigid projecting finger  121  which extends from the mask opening portion  110 . Extending radially outwardly from the projecting finger  121  are a series of axially spaced thin and flexible fins or gills  122  and/or  125 . Fins or gills  122  and/or  125  are preferably integrally molded with, and made of the same material as, the projecting finger  121 . In a preferred embodiment, the entire mask portion  100  could be integrally molded in one piece from a durable biocompatible material such as urethane or polyvinyl chloride (PVC). The fins or gills  122  and/or  125  are designed so that they have a degree of flexibility, and thereby can be compressed or flexed to conform to the area above the esophagus E at the pharyngeal side of the cricoid C. The fins or gills  122  and/or  125  therefore conform and seat against the pharyngeal side of the cricoid C, and the associated area above the esophagus E opposite the pharyngeal side of the cricoid C, thereby anchoring the mask opening portion  110  in the area above the laryngeal opening of the larynx L. 
     FIGS. 2 and 3 show details of the mask portion  100  of FIG.  1 . The mask portion  100  includes an upper or proximal mask opening portion  110  and a lower or distal seating tip  120 . The mask opening portion  110  includes an opening  101  which connects with the large conduit  204  in the airway tube  200 . A flange  102  may at least partially surround the opening  101  to assist in assembly of the distal end  201  of airway tube  200  to the mask portion  100 . The mask opening portion  110  includes a mask opening  111  which connects the large conduit  204  of the distal end  201  of airway tube  200  to the laryngeal opening of the larynx L of the patient P. As shown in FIG. 3, the mask opening  111  is formed by a plurality of apertures  142  disposed in and through the surface of the mask opening portion  110 . These apertures  142  are used to pass air, oxygen, anesthesia or other gases from the airway tube  200  through the mask portion  100  and into the patient&#39;s larynx L. The apertures  142  are separated from one another by a series of bars  143  forming a grate. The bars  143  act to restrain any anatomical portion, and in particular the epiglottis G, from entering into and blocking or partially blocking, the mask opening  111 , thereby preventing obstruction of the delivery or removal of gases from the respiratory system of the patient P. 
     As shown in particular in FIG. 3, the mask opening portion  110  can be formed to have a shape  112  which is approximately trapezoidal, which shape  112  is designed to closely follow the shape of the laryngeal opening of the larynx L above which the mask opening portion  110  is placed. In this manner, the mask opening portion  110  can serve to block the laryngeal opening of the larynx L from the ingress of material or any other object into the larynx L and respiratory system of the patient P, other than the gases which are delivered via the large conduit  204  of the airway tube  200 . 
     In the mask portion of FIGS. 2 and 3, the seating tip  120  has a shovel-shaped design. As may be seen in FIG. 3, the fins or gills  122  and  125  taper in width from the proximal end to the distal end of the projecting finger  121 . In addition, at least some of the fins or gills  122  and/or  125  on the side of the mask portion  100  which faces away from the larynx L have a curved shape which extends from one side of two support arms  145  projecting outwardly from the projecting finger  121 . As shown in FIG. 2, at least some of the fins or gills  122  on the side of the mask portion  100  which faces away from the larynx L may also include undulations  146  across their width. These undulations  146  are used to compensate for flexing or expansion of the seating tip  120  in the direction F as the seating tip is inserted into, and conforms to, the area above the esophagus E where the pharyngeal side of the cricoid C is located and upon which the seating tip  120  seats. On the side of the support arms  145  opposite the fins or gills  122  are fins or gills  125 . These fins or gills  125  preferably do not contain undulations, but instead compress as the seating tip flexes or expands in the direction F. 
     The shovel-shaped, tapered and flexible design of the embodiment shown in FIGS. 2 and 3 is preferable in that it can be used in a wide variety of patients, as the shape and flexibility of the seating tip  120  allows it to conform to, and seat in, many different sizes and shapes of patient airways and sizes and shapes of the area above the esophagus at the location of the pharyngeal side of the cricoid C where the seating tip  120  seats. 
     FIGS. 4 and 5 show an alternative, second embodiment of the mask portion  100 ′ of the present invention. The embodiment of FIGS. 4 and 5, like the embodiment of FIGS. 1-3, includes an upper or proximal mask opening portion  110 ′ and a lower or distal seating tip  120 ′. The mask opening portion  110 ′ includes an opening  101 ′ which connects with the distal end  201  of large conduit  204  in the airway tube  200 . A flange  102 ′ may at least partially surround the opening  101 ′ to assist in assembly of the airway tube  200  to the mask portion  100 ′. The mask opening portion  110 ′ includes a mask opening  111 ′ which connects the large conduit  204  of the airway tube  200  to the laryngeal opening of the larynx L of the patient P. As shown in FIG. 4, the mask opening  111 ′ is formed by a plurality of apertures  142  disposed in and through the surface of the mask opening portion  110 ′ These apertures  142  are used to pass air, oxygen, anesthesia or other gases from the airway tube  200  through the mask portion  100 ′ and into the patient&#39;s larynx L. The apertures  142  are separated from one another by a series of bars or grates  143 . The bars or grates  143  act to restrain any anatomical portion, and in particular the epiglottis G, from entering into and blocking or partially blocking, the mask opening  111 ′, thereby preventing obstruction of the delivery or removal of gases from the respiratory system of the patient P. 
     As shown in particular in FIG. 4, the mask opening portion  110 ′ can be formed to have a shape  112 ′ which is approximately trapezoidal, which shape  112 ′ is designed to closely follow the shape of the laryngeal opening of the larynx L above which the mask opening portion  110 ′ is placed. In this manner, the mask opening portion  110 ′ can serve to block the laryngeal opening of the larynx L from the ingress of material or any other object into the larynx L and respiratory system of the patient P, other than the gases which are delivered via the large conduit of the airway tube  200 . 
     FIG. 6 shows an additional embodiment of the mask portion  100 ″, which includes a modified configuration of the fins or gills  122 ″ and projecting finger  121 ″ of the seating tip  120 ″, as well as a slightly different configuration of the shape  112 ″ and the mask opening portion  110 ″. The operation of the embodiment of FIG. 6, however, is identical to the embodiments described above. 
     FIG. 7 shows the artificial airway of the present invention in place in a patient P, with the inflatable cuff  800  uninflated, and in place adjacent the tongue T and the portion of the oro-pharynx near the uvula U, but prior to retraction. FIG. 8 shows the artificial airway in place in a patient P, after retraction and inflation of the inflatable cuff  800 . As shown in FIG. 8, the artificial airway of the present invention, and in particular the mask opening portion  110 , seats properly in place above the laryngeal opening L of the patient P. As may also be seen in FIG. 8, the seating tip  120  seats in the area above the entrance to the esophagus E against the pharyngeal side of the cricoid C and the portion of the pharynx opposite the pharyngeal side of the cricoid C. 
     Operation of the various embodiments and methods of their use will now be described, with reference to FIGS. 7 and 8. The patient&#39;s P mouth is opened and the seating tip  120 , airway tube  200  and inflatable cuff  800  are lubricated for ease of insertion. The artificial airway of the present invention is inserted down the oral cavity O, with the mask opening  111  facing toward the tongue T during insertion. The airway tube  200  is pushed inwardly into the oral cavity O and the seating tip  120  is fed along the hard and soft palate, the back of the oropharynx, and into the cricopharynx adjacent the cricoid C. When resistance is felt due to interaction between the seating tip and the pharyngeal side of the cricoid C above the entrance to the esophagus E, insertion is halted. That position is shown in FIG.  7 . Once the seating tip  120  seats against the pharyngeal side of the cricoid C, the individual inserting the artificial airway of the present invention will feel the seating tip  120  seating, and therefore will know that the artificial airway of the present invention is properly in place. The airway tube  200  may then be retracted or pulled back slightly outwardly, so that the mask opening portion  110  pushes the epiglottis G up and away from the mask opening  111 , as shown in FIG.  8 . Thereafter, the inflatable cuff  800  is expanded by applying fluid under pressure to connector  403 , which fluid travels down the small conduit of the airway tube  200  and enters the interior of inflatable cuff  800  to expand inflatable cuff  800  until it contacts the tongue T and the opposed portion of the oro-pharynx behind the uvula U, thereby securing the artificial airway of the present invention in place. That condition is also shown in FIG.  8 . Once the artificial airway is in place, any mechanism or structure which is used for the delivery of gases to the respiratory system of the patient may be connected to connection end  300 , or the connection end could be left free to allow spontaneous ventilation by the patient P. 
     Thus, there is shown and described a unique design and concept of an artificial airway and method of its use and insertion. While this description is directed to particular embodiments, it is understood that those skilled in the art may conceive modifications and/or variations to the specific embodiments shown and described herein. Any such modifications or variations which fall within the purview of this description are intended to be included as part of the invention. It is understood that the description herein is intended to be illustrative only and is not intended to be limitative. Rather, the scope of the invention described herein is limited only by the claims.