Abstract:
An epidermal dressing includes an appliance for linking an electromagnetic spectrum sensor with a cannula administering an intravascular infusate. The appliance includes a body and a fitting coupled to the body. The body is configured to space a connector of the cannula from the epidermis. The fitting includes a first arrangement that is configured to retain the electromagnetic spectrum sensor for sensing the infusate in perivascular tissue, and a second arrangement that is configured to release the electromagnetic spectrum sensor from the first arrangement.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
       [0001]    This application claims the priority of U.S. Provisional Application No. 61/640,542, filed 30 Apr. 2012, and also claims the priority of U.S. Provisional Application No. 61/609,865, filed 12 Mar. 2012, each of which are hereby incorporated by reference in their entirety. 
     
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
       [0002]    Not Applicable 
       BACKGROUND OF THE INVENTION 
       [0003]      FIG. 8  shows a typical arrangement for intravascular infusion. As the terminology is used herein, “intravascular” preferably refers to being situated in, occurring in, or being administered by entry into a blood vessel, thus “intravascular infusion” preferably refers to introducing a fluid into a blood vessel. Intravascular infusion accordingly encompasses both intravenous infusion (administering a fluid into a vein) and intra-arterial infusion (administering a fluid into an artery). 
         [0004]    A cannula  20  is typically used for administering fluid via a subcutaneous blood vessel. Typically, cannula  20  is inserted through epidermis E at an insertion site S and punctures, for example, the cephalic vein, basilica vein, median cubital vein, or any suitable vein for an intravenous infusion. Similarly, any suitable artery may be used for an intra-arterial infusion. 
         [0005]    Cannula  20  typically is in fluid communication with a fluid source  22 . Typically, cannula  20  includes an extracorporeal connector, e.g., a hub  20   a , and a transcutaneous sleeve  20   b . Fluid source  22  typically includes one or more sterile containers that hold the fluid(s) to be administered. Examples of typical sterile containers include plastic bags, glass bottles or plastic bottles. 
         [0006]    An administration set  30  typically provides a sterile conduit for fluid to flow from fluid source  22  to cannula  20 . Typically, administration set  30  includes tubing  32 , a drip chamber  34 , a flow control device  36 , and a cannula connector  38 . Tubing  32  is typically made of polypropylene, nylon, or another flexible, strong and inert material. Drip chamber  34  typically permits the fluid to flow one drop at a time for reducing air bubbles in the flow. Tubing  32  and drip chamber  34  are typically transparent or translucent to provide a visual indication of the flow. Typically, flow control device  36  is positioned upstream from drip chamber  34  for controlling fluid flow in tubing  34 . Roller clamps and Dial-A-Flo®, manufactured by Hospira, Inc. (Lake Forest, Ill., USA), are examples of typical flow control devices. Typically, cannula connector  38  and hub  20   a  provide a leak-proof coupling through which the fluid may flow. Luer-Lok™, manufactured by Becton, Dickinson and Company (Franklin Lakes, N.J., USA), is an example of a typical leak-proof coupling. 
         [0007]    Administration set  30  may also include at least one of a clamp  40 , an injection port  42 , a filter  44 , or other devices. Typically, clamp  40  pinches tubing  32  to cut-off fluid flow. Injection port  42  typically provides an access port for administering medicine or another fluid via cannula  20 . Filter  44  typically purifies and/or treats the fluid flowing through administration set  30 . For example, filter  44  may strain contaminants from the fluid. 
         [0008]    An infusion pump  50  may be coupled with administration set  30  for controlling the quantity or the rate of fluid flow to cannula  20 . The Alaris® System manufactured by CareFusion Corporation (San Diego, Calif., USA) and Flo-Gard® Volumetric Infusion Pumps manufactured by Baxter International Inc. (Deerfield, Ill., USA) are examples of typical infusion pumps. 
         [0009]    Unintended infusing typically occurs when fluid from cannula  20  escapes from its intended vein/artery. Typically, unintended infusing causes an abnormal amount of a substance to diffuse or accumulate in perivascular tissue or cells and may occur, for example, when (i) cannula  20  causes a brittle vein/artery to rupture; (ii) cannula  20  improperly punctures the vein/artery; (iii) cannula  20  is improperly sized; or (iv) infusion pump  50  administers fluid at an excessive flow rate. Unintended infusing of a non-vesicant fluid is typically referred to as “infiltration,” whereas unintended infusing of a vesicant fluid is typically referred to as “extravasation.” 
         [0010]    The symptoms of infiltration or extravasation typically include blanching or discoloration of the epidermis E, edema, pain, or numbness. The consequences of infiltration or extravasation typically include skin reactions such as blisters, nerve compression, acute limb compartment syndrome, or necrosis. Typical care for infiltration or extravasation includes applying warm compresses, administering hyaluronidase or phentolamine, fasciotomy, or amputation. 
       BRIEF SUMMARY OF THE INVENTION 
       [0011]    Embodiments according to the present invention include an appliance for linking an electromagnetic spectrum sensor with a cannula administering an intravascular infusate. The cannula includes an extracorporeal connector coupled to a transcutaneous sleeve that penetrates an epidermis at an insertion site. The appliance includes a body and a fitting coupled to the body. The body is configured to space the connector from the epidermis. The fitting has first and second arrangements. The first arrangement is configured to retain the electromagnetic spectrum sensor for sensing the infusate in perivascular tissue proximate the sleeve, and second arrangement is configured to release the electromagnetic spectrum sensor from the first arrangement. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    The accompanying drawings, which are incorporated herein and constitute part of this specification, illustrate exemplary embodiments of the invention, and, together with the general description given above and the detailed description given below, serve to explain the features, principles, and methods of the invention. 
           [0013]      FIG. 1A  is a plan view illustrating an embodiment of an appliance according to the present disclosure. Portions of a fitting and a frame are shown in dashed line. 
           [0014]      FIG. 1B  is a bottom view of an undersurface of the appliance shown in  FIG. 1A . 
           [0015]      FIG. 1C  is a cross-section view taken along line IC-IC in  FIG. 1 . 
           [0016]      FIG. 2A  is a partial cross-section view illustrating a first arrangement of the appliance shown in  FIG. 1A  retaining an electromagnetic spectrum sensor. 
           [0017]      FIG. 2B  is a partial cross-section view illustrating a second arrangement of the appliance shown in  FIG. 1A  releasing an electromagnetic spectrum sensor. 
           [0018]      FIG. 3  is a partially exploded perspective view illustrating a dressing assembly including an embodiment of an appliance according to the present disclosure, an electromagnetic spectrum sensor, a cannula, and a barrier film. 
           [0019]      FIG. 4  is an exploded view of the dressing assembly shown in  FIG. 3 . 
           [0020]      FIG. 5A  is a cross-section view illustrating a first arrangement of the appliance shown in  FIG. 3  retaining an electromagnetic spectrum sensor. 
           [0021]      FIG. 5B  is a cross-section view illustrating a second arrangement of the appliance shown in  FIG. 3  releasing an electromagnetic spectrum sensor. 
           [0022]      FIG. 6  is a partially exploded perspective view illustrating a dressing assembly including an embodiment of an appliance according to the present disclosure, an electromagnetic spectrum sensor, a cannula, and a barrier film. 
           [0023]      FIG. 7  is an exploded view of the dressing assembly shown in  FIG. 6 . 
           [0024]      FIG. 8  is a schematic view illustrating a typical set-up for infusion administration. 
       
    
    
       [0025]    In the figures, the thickness and configuration of components may be exaggerated for clarity. The same reference numerals in different figures represent the same component. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0026]    The following description and drawings are illustrative and are not to be construed as limiting. Numerous specific details are described to provide a thorough understanding of the disclosure. However, in certain instances, well-known or conventional details are not described in order to avoid obscuring the description. 
         [0027]    Reference in this specification to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the disclosure. The appearances of the phrase “in one embodiment” in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Moreover, various features are described which may be exhibited by some embodiments and not by others. Similarly, various features are described which may be included in some embodiments but not other embodiments. 
         [0028]    The terms used in this specification generally have their ordinary meanings in the art, within the context of the disclosure, and in the specific context where each term is used. Certain terms in this specification may be used to provide additional guidance regarding the description of the disclosure. It will be appreciated that a feature may be described more than one-way. 
         [0029]    Alternative language and synonyms may be used for any one or more of the terms discussed herein. No special significance is to be placed upon whether or not a term is elaborated or discussed herein. Synonyms for certain terms are provided. A recital of one or more synonyms does not exclude the use of other synonyms. The use of examples anywhere in this specification including examples of any terms discussed herein is illustrative only, and is not intended to further limit the scope and meaning of the disclosure or of any exemplified term. 
         [0030]      FIGS. 1A-2B  show an embodiment of an appliance  100  that includes (i) a fitting  110  for receiving an electromagnetic spectrum sensor  1000 , which senses if fluid is infusing perivascular tissue around cannula  20 ; (ii) a frame  120  for distributing forces acting on appliance  100  to the epidermis E; and (iii) a body  130  for covering fitting  110  and frame  120  with a soft haptic surface. Appliance  100  preferably couples electromagnetic spectrum sensor  1000  with the epidermis E proximate the insertion site S. Preferably, appliance  100  positions sensor face  1000   a  relative to the epidermis E within approximately 10 centimeters of the insertion site S and preferably approximately one centimeter to approximately five centimeters away from the insertion site S. 
         [0031]    Electromagnetic spectrum sensor  1000  preferably aids in diagnosing infiltration or extravasation. Preferably, electromagnetic radiation  1002  is emitted via a sensor face  1000   a  of electromagnetic spectrum sensor  1000  and electromagnetic radiation  1004  is received via sensor face  1000   a . Emitted electromagnetic radiation  1002  passes through the epidermis E into the perivascular tissue P. Referring to  FIG. 1C , the perivascular tissue P in the vicinity of a blood vessel V preferably includes the cells or interstitial compartments that may become unintentionally infused, e.g., infiltrated or extravasated by fluid from cannula  20 . Received electromagnetic radiation  1004  is at least a portion of emitted electromagnetic radiation  1002  that is reflected, scattered, diffused, or otherwise redirected from the perivascular tissue P through the epidermis E to sensor face  1000   a.    
         [0032]    Emitted and received electromagnetic radiations  1002  and  1004  are preferably in the near-infrared portion of the electromagnetic spectrum. As the terminology is used herein, “near infrared” refers to electromagnetic radiation having wavelengths between approximately 1,400 nanometers and approximately 700 nanometers—proximate the nominal edge of red light in the visible light portion of the electromagnetic spectrum. These wavelengths correspond to a frequency range of approximately 215 terahertz to approximately 430 terahertz. Preferably, emitted and received electromagnetic radiations  1002  and  1004  are tuned to a common peak wavelength. According to one embodiment, emitted and received electromagnetic radiations  1002  and  1004  each have a peak centered at approximately 950 nanometers. According to other embodiments, emitted electromagnetic radiation  1002  includes a wavelength profile in a band between a relatively low wavelength and a relatively high wavelength, and received electromagnetic radiation  1004  encompasses at least the band between the relatively low and high wavelengths. According to still other embodiments, received electromagnetic radiation  1004  is tuned to a wavelength profile in a band between relatively low and high wavelengths and emitted electromagnetic radiation  1002  encompasses at least the band between the relatively low and high wavelengths. 
         [0033]    The possibility of fluid infusing the perivascular tissue P preferably is indicated by analyzing received electromagnetic radiation  1004 . According to one embodiment, discrete pulses of emitted electromagnetic radiation  1002  cause corresponding pulses of received electromagnetic radiation  1004 . Preferably, a processor (not shown) or another suitable device analyzes changes over time in received electromagnetic radiation  1004  for providing an indication of fluid infusing the perivascular tissue P. 
         [0034]    Electromagnetic spectrum sensor  1000  may be coupled to the processor via a lead  1010 . According to some embodiments, electromagnetic spectrum sensor  1000  and the processor may be coupled to the processor wirelessly rather than via lead  1010 , or electromagnetic spectrum sensor  1000  may incorporate the processor. 
         [0035]    Electromagnetic spectrum sensor  1000  preferably includes an anatomic sensor. As the terminology is used herein, “anatomic” preferably refers to the structure of an Animalia body and an “anatomic sensor” preferably is concerned with sensing a change over time of the structure of the Animalia body. By comparison, a physiological sensor is concerned with sensing the functions and activities of an Animalia body, e.g., pulse, at a point in time. 
         [0036]    Electromagnetic spectrum sensor  1000  may be coupled to the epidermis E separately from typical contamination barriers (not shown in  FIGS. 1A-2B ). Typical contamination barriers may (i) protect the insertion site S; and (ii) allow the insertion site S to be observed. Preferably, appliance  100  and a contamination barrier are coupled to the epidermis E separately, e.g., at different times or in different steps of a multiple step process. According to one embodiment, a contamination barrier that overlies the insertion site S may also overlie portions of the cannula C and/or appliance  100 . According to another embodiment, a contamination barrier may overlie the insertion site S and be spaced from appliance  100 . 
         [0037]    Appliance  100  preferably includes different arrangements that permit electromagnetic spectrum sensor  1000  to be reused with a plurality of appliances  100 . As the terminology is used herein, “arrangement” preferably refers to a relative configuration, formation, layout or disposition of appliance  100  and electromagnetic spectrum sensor  1000 . Preferably, appliance  100  includes a fitting  110  that provides two arrangements with respect to electromagnetic spectrum sensor  1000 . Referring to  FIG. 2A , a first arrangement of fitting  110  preferably retains electromagnetic spectrum sensor  1000  relative to appliance  100  for monitoring infiltration or extravasation during an infusion with cannula  20 . Referring to  FIG. 2B , a second arrangement of fitting  110  preferably releases electromagnetic spectrum sensor  1000  from the first arrangement. Accordingly, electromagnetic spectrum sensor  1000  may be decoupled from appliance  100  in the second arrangement of fitting  110 , e.g., during patient testing or relocation, and subsequently recoupled in the first arrangement of fitting  110  such that sensor  1000  has approximately the same relationship to the epidermis E and the perivascular tissue P. 
         [0038]    Relative movement between electromagnetic spectrum sensor  1000  and appliance  100  preferably is constrained between the first and second arrangements. Preferably, fitting  110  includes a chute  112  that extends along an axis A between a first end  114  and a second end  116 . According to one embodiment, chute  112  preferably is centered about axis A, which preferably is obliquely oriented relative to the epidermis E. Chute  112  and electromagnetic spectrum sensor  1000  preferably are cooperatively sized and shaped so that (i) electromagnetic spectrum sensor  1000  can be inserted in first end  114  in only one relative orientation; and (ii) relative movement between the first and second arrangements is constrained to substantially only translation along axis A. As the terminology is used herein, “translation” refers to movement without rotation or angular displacement. Electromagnetic spectrum sensor  1000  preferably does not rub the epidermis E during translation along axis A. Accordingly, forces that may tend to distort the epidermis E preferably are prevented or at least minimized while moving electromagnetic spectrum sensor  1000  between the first and second arrangements of fitting  110 . It is believed that reducing distortion of the epidermis E reduces distortion of subcutaneous tissue including the perivascular tissue P and the blood vessel V, and therefore also reduces the likelihood of displacing cannula  20  while moving electromagnetic spectrum sensor  1000  between the first and second arrangements of fitting  110 . 
         [0039]    Appliance  100  preferably includes a latch  118  for retaining electromagnetic spectrum sensor  1000  in the first arrangement of fitting  110 . Preferably, latch  118  is resiliently biased into engagement with a cooperating feature on electromagnetic spectrum sensor  1000  in the first arrangement. According to one embodiment, latch  118  preferably includes a cantilever  118   a  that has a recess or aperture  118   b  for cooperatively receiving a projection  1000   b  of electromagnetic spectrum sensor  1000  in the first arrangement. In the second arrangement, latch  118  may be manipulated to alter the nominal form of cantilever  118   a  for releasing projection  1000   b  from recess or aperture  118   a  so that electromagnetic spectrum sensor  1000  may be withdrawn from chute  112  though first end  114 . Preferably, latch  118  provides a positive indication, e.g., a tactile or audible notification, that electromagnetic spectrum sensor  1000  is in at least one of the first and second arrangements. According to other embodiments, latch  118  may include snaps, a cap, or another suitable device that, in the first arrangement, retains electromagnetic spectrum sensor  1000  in fitting  110  and, in the second arrangement, releases electromagnetic spectrum sensor  1000  from fitting  110 , e.g., allowing electromagnetic spectrum sensor  1000  to separate from appliance  100 . 
         [0040]    Fitting  110  preferably permits reusing electromagnetic spectrum sensor  1000 . The first and second arrangements of fitting  110  preferably permit electromagnetic spectrum sensor  1000  to be decoupled and recoupled with appliance  100 , or decoupled from a first patient&#39;s appliance  100  and coupled to a second patient&#39;s appliance  100 . Thus, fitting  110  preferably permits reusing electromagnetic spectrum sensor  1000  with a plurality of appliances  100  that are individually coupled to patients&#39; epidermises. 
         [0041]    Appliance  100  also preferably maintains electromagnetic spectrum sensor  1000  in a substantially consistent location relative to the perivascular tissue P. Preferably, chute  112  delimits movement of electromagnetic spectrum sensor  1000  such that sensor face  1000   a  of electromagnetic spectrum sensor  1000  is disposed proximate second end  116  of fitting  110  in the first arrangement. According to one embodiment, electromagnetic spectrum sensor  1000  projects from appliance  100  such that sensor face  1000   a  preferably is disposed beyond second end  116  toward the epidermis E for substantially eliminating or at least minimizing a gap between sensor face  1000   a  and the epidermis E. Thus, appliance  100  in the first arrangement of fitting  110  preferably maintains a substantially consistent relative position between sensor face  1000   a  and the epidermis E for sensing over time if fluid from cannula  20  is infusing the perivascular tissue P. 
         [0042]    Appliance  100  preferably resists forces that tend to change the position of electromagnetic spectrum sensor  1000  relative to the perivascular tissue P. Pulling or snagging lead  1010  is one example of the forces that frame  120  distributes over a larger area of the epidermis E than the areas overlaid by sensor face  1000   a  or by fitting  110 . Frame  120  therefore preferably enhances maintaining a substantially consistent relative position between sensor face  1000   a  and the epidermis E for sensing over time if fluid from cannula  20  is infusing the perivascular tissue P. 
         [0043]    Appliance  100  preferably includes a relatively rigid skeleton and a relatively supple covering. Preferably, the skeleton includes fitting  110  for interacting with electromagnetic spectrum sensor  1000 , as discussed above, and frame  120  for distributing to the epidermis E forces acting on fitting  110 . Frame  120  preferably includes a hoop  122  coupled with fitting  110  by at least one arm (four arms  124   a - 124   d  are indicated in  FIG. 1A ). According to one embodiment, hoop  122  preferably includes an uninterrupted annulus disposed about fitting  110 . According to another embodiment, hoop  122  preferably includes a plurality of segments disposed about fitting  110 . 
         [0044]    The composition and dimensions of the skeleton preferably are selected so that forces acting on appliance  100  are distributed to the epidermis E. According to one embodiment, fitting  110  and frame  120  preferably are formed as a single independent component, e.g., integrally molded with a substantially homogeneous chemical compound. According to another embodiment, fitting  110  and frame  120  may be composed of more than one compound and/or may include an assembly of a plurality of pieces. Appliance  100  may be subjected to a variety of forces, for example, due to pulling or snagging lead  1010 , and preferably the dimensions of hoop  122  and arms  124   a - 124   d  are selected for reacting to these forces. According to one embodiment, the dimensions of frame  120  preferably include arm  124   a  being relatively more robust than arms  124   b - 124   d , arms  124   c  and  124   d  being relatively the least robust, and arm  124   b  being relatively less robust than arm  124   a  and relatively more robust than arms  124   c  and  124   d . Thus, according to this embodiment, appliance  100  reacts to forces, e.g., an approximately eight-pound force pulling lead  1010  away from the epidermis E, that may tend to move electromagnetic spectrum sensor  1000  by (i) distributing a compression force to a first area of the epidermis E proximate arm  124   a ; and (ii) distributing a tension force to a second area of the epidermis proximate arm  124   b . The first and second areas preferably are larger than a third area of the epidermis E that the sensor face  1000   a  and/or fitting  110  overlie. Similarly, arms  124   c  and  124   d  preferably distribute compression and tension forces to fourth and fifth areas of the epidermis in response to, e.g., torsion forces acting on lead  1010 . Appliance  100  therefore preferably resists changes to the relative position between sensor face  1000   a  and the epidermis E by distributing over relatively large areas of the epidermis E the forces that may tend to move electromagnetic spectrum sensor  1000  in the first arrangement of fitting  110 . 
         [0045]    The relatively supple covering of appliance  100  preferably includes a body  130  that presents a soft haptic exterior surface overlying the skeleton. Preferably, body  130  has a relatively lower hardness as compared to fitting  110  and frame  120 . According to one embodiment, body  130  preferably consists of a first homogeneous chemical compound, fitting  110  and frame  120  preferably consist of a second homogeneous chemical compound, and the first homogeneous chemical compound has a lower hardness than the second homogeneous chemical compound. The first homogeneous chemical compound preferably includes silicone or another material having a relatively low durometer, e.g., approximately Shore A 10 to approximately Shore A 60, and the second homogeneous chemical compound preferably includes polyurethane or another material having a relatively higher durometer, e.g., approximately Shore D 30 to approximately Shore D 70. Accordingly, the skeleton including fitting  110  and frame  120  preferably provides a structure for distributing forces applied to appliance  100 , and body  130  provides a soft haptic exterior surface that imparts to appliance  100  a desirable tactile feel, which may be characterized as soft rather than hard to the touch. Preferably, fitting  110  includes a polypropylene homopolymer (e.g., Pro-fax 6523, manufactured by LyondellBasell Industrial Holdings, B.V., Rotterdam, The Netherlands) and body  130  includes a thermoplastic elastomer (e.g., Versaflex™ from PolyOne Corporation, Avon Lake, Ohio, USA). 
         [0046]    A process for manufacturing appliance  100  preferably includes covering the skeleton with the soft haptic exterior surface. According to one embodiment, appliance  100  is molded in a multiple step process. Preferably, one step includes molding fitting  110  and frame  120  in a mold, another step includes adjusting the mold, and yet another step includes molding body  130  over fitting  110  and frame  120  in the adjusted mold. An apparatus for molding fitting  110 , frame  120  and body  130  preferably includes a common mold portion, a first mold portion cooperating with the common mold portion for molding fitting  110  and frame  120 , and a second mold portion cooperating with the common mold portion for over-molding body  130 . Preferably, the common and first mold portions receive a first shot of material to mold fitting  110  and frame  120 , the mold is adjusted by decoupling the first mold portion from the common mold portion and coupling the second mold portion with the common mold portion, and the common and second mold portions receive a second shot of material to mold body  130 . Fitting  110  and frame  120  preferably remain in the common mold portion while decoupling the first mold portion and coupling the second mold portion. Accordingly, appliance  100  is preferably molded in a two-shot process with a skeleton including fitting  110  and frame  120  being subsequently covered with a soft haptic exterior surface including body  130 . 
         [0047]    Appliance  100  may be wholly biocompatible and/or include a biocompatible layer for contacting the epidermis E. As the terminology is used herein, “biocompatible” preferably refers to compliance with Standard 10993 promulgated by the International Organization for Standardization (ISO 10993) and/or Class VI promulgated by The United States Pharmacopeial Convention (USP Class VI). Other regulatory entities, e.g., National Institute of Standards and Technology, may also promulgate standards that may additionally or alternatively be applicable regarding biocompatibility. 
         [0048]    Referring particularly to  FIG. 1C , a foundation  150  preferably (1) couples appliance  100  and the epidermis E; and (2) separates the rest of appliance  100  from the epidermis E. Preferably, foundation  150  includes a panel  152  that is coupled to an undersurface of appliance  100  confronting the epidermis E (shown in  FIG. 2A ). According to one embodiment, panel  152  is adhered to the undersurface of appliance  100 . Panel  152  preferably includes polyurethane and occludes second end  116  for providing a barrier between the epidermis E and sensor face  1000   a  in the second arrangement. According to other embodiments, body  130  preferably includes panel  152 . For example, a substantially homogeneous material may be used for integrally molding body  130  and panel  152 . Preferably, panel  152  is biocompatible according to ISO 10993 and/or USP Class VI. 
         [0049]    Foundation  150  preferably includes an adhesive coating  154  for adhering appliance  100  to the epidermis E. Adhesive  154  preferably includes an acrylic adhesive or another medical grade adhesive that is biocompatible according to ISO 10993 and/or USP Class VI. According to one embodiment, adhesive  154  may be applied to all or a portion of panel  152  on the surface that confronts the epidermis E. According to other embodiments, panel  152  may be omitted and adhesive  154  may directly adhere body  130  and/or fitting  110  to the epidermis E. 
         [0050]    Adhesive  154  preferably may be adjusted to vary the bond strength between appliance  100  and the epidermis E. Preferably, stronger or more adhesive  154  may be used for coupling appliance  100  to relatively robust skin, e.g., adult skin, and weaker or less adhesive  154  may be used for coupling appliance  100  to relatively delicate skin, e.g., pediatric skin. 
         [0051]    Preferably, appliance  100  permits viewing the epidermis E with visible light and generally rejects interference by ambient sources with emitted and received electromagnetic radiation  1002  and  1004 . As the terminology is used herein, “visible light” refers to energy in the visible portion of the electromagnetic spectrum, for example, wavelengths between approximately 380 nanometers and approximately 760 nanometers. These wavelengths correspond to a frequency range of approximately 400 terahertz to approximately 790 terahertz. Preferably, body  130  is transparent or translucent to visible light for viewing the epidermis E under at least a portion of appliance  100 . According to one embodiment, fitting  110  and frame  120  preferably are also transparent or translucent to visible light. According to other embodiments, fitting and/or frame  120  may be generally opaque to visible light. According to still other embodiments, body  130  may be generally opaque to visible light or fitting  110  and/or frame  120  may be may be transparent or translucent to visible light. Preferably, fitting  110 , frame  120  and body  130 , but not foundation  150 , absorb or block electromagnetic radiation with wavelengths that approximately correspond to emitted and received electromagnetic radiation  1002  and  1004 , e.g., radiation in the near-infrared portion of the electromagnetic spectrum. Accordingly, appliance  100  preferably permits visible light viewing of the epidermis E and minimizes ambient source interference with emitted and received electromagnetic radiation  1002  and  1004 . 
         [0052]    Appliance  100  preferably is advantageous at least because (i) the location of a patient monitor, e.g., electromagnetic spectrum sensor  1000 , is not linked by appliance  100  to cannula  20  or to an IV dressing for the insertion site S; (ii) appliance  100  is interchangeably useable with typical dressings for the IV insertion site S; and (iii) minimal stress and strain is transferred by appliance  100  to the epidermis E when changing between the first and second arrangements of fitting  110 . As the terminology is used herein, “link” or “linking” preferably refers to at least approximately fixing the relative locations of at least two objects. 
         [0053]      FIGS. 3-5B  show an embodiment of an appliance  200  that preferably includes (i) a fitting  210  for receiving electromagnetic spectrum sensor  1000 , which senses if fluid is infusing perivascular tissue around cannula  20 ; (ii) a frame  220  for distributing forces acting on appliance  200  to the epidermis E; and (iii) a body  230  for covering fitting  210  and frame  220  with a soft haptic surface. As compared to appliance  100  ( FIGS. 1A-2B ), the location of cannula  20  is linked by appliance  200  to electromagnetic spectrum sensor  1000 . Appliance  200  preferably positions sensor face  1000   a  relative to the epidermis E within approximately five centimeters of the insertion site S and preferably approximately one centimeter to approximately three centimeters away from the insertion site S. 
         [0054]    Appliances  100  and  200  preferably include some features and advantages that are comparable. As the terminology is used herein, “comparable” refers to similar, if not identical, compositions, constructions, properties, functions or purposes, and preferably combinations thereof. Preferably, features of appliances  100  and  200  that are comparable include (i) fittings  110  and  210 ; (ii) chutes  112  and chute  212 ; (iii) latches  118  and  218 ; (iv) hoops  122  and  222 ; and (v) arms  124  and  224 . Appliance  200  may also include a foundation  250 , which is comparable to foundation  150 , for separating and coupling the rest of appliance  200  with respect to the epidermis E. Additional descriptions of comparable features or advantages may be found herein and may not be repeated in their entirety. 
         [0055]    Appliance  200  preferably includes one or more wings  240  in addition to at least some of the features and advantages of appliance  100 . Preferably, individual wings  240  (i) link electromagnetic spectrum sensor  1000  with respect to cannula  20 ; (ii) separate cannula  20  from the epidermis E; (iii) provide resistance to forces that tend to change relative to the perivascular tissue P; and/or (iv) stabilize the positions of cannula  20  and electromagnetic spectrum sensor  1000  relative to the epidermis E. Each wing  240  preferably is coupled with fitting  210 , frame  220  or body  230  and includes a first surface  242  for contiguously engaging cannula  20  and a second surface  244  for contiguously engaging the epidermis E. According to one embodiment, individual wings  240  include portions of frame  220  and body  230 . 
         [0056]    Appliance  200  preferably includes plural locating options for linking electromagnetic spectrum sensor  1000  with respect to cannula  20 . According to one embodiment, individual wings  240  preferably extend in two generally opposite lateral directions with respect to axis A of fitting  210 . Accordingly, a footprint of appliance  200  on the epidermis E preferably is approximately tee-shaped or approximately wye-shaped and cannula  20  may be located on either one of the wings  240  on opposite sides of electromagnetic spectrum sensor  1000 . According to other embodiments, a single wing  240  preferably extends in one lateral direction with respect to axis A of fitting  210 . Accordingly, a footprint of appliance  200  on the epidermis E preferably is approximately ell-shaped with cannula  20  being located on wing  240  extending to one side of electromagnetic spectrum sensor  1000 . Preferably, individual appliances  200  with single wings  240  that extend on different sides of electromagnetic spectrum sensor  1000  may be included in a set. Accordingly, one or another of appliances  200  in the set preferably is selected to provide the most suitable locating option for linking electromagnetic spectrum sensor  1000  with respect to cannula  20 . The most suitable locating option preferably is selected based on one or more factors including: (i) the location on the patient of the insertion site S; (ii) the orientation of cannula  20  relative to the insertion site; (iii) minimizing movement of cannula  20  or electromagnetic spectrum sensor  100  due to pulling or snagging tubing  32  or lead  1010 ; and (iv) comfort of the patient. A single wing  240  may make appliance  200  more compact and plural wings  240  on a single appliance  200  may provide additional options for locating electromagnetic spectrum sensor  1000  relative to cannula  20 . Further, appliance  200  may include perforations or shear line indicators for separating, e.g., tearing-off or cutting, at least one wing  240  from the rest of appliance  200 . Accordingly, the size of appliance  200  may be compacted and/or appliance  200  may be made wingless in the manner of appliance  100 . Thus, an advantage of each of the aforementioned embodiments is increasing the options for how an anatomical sensor may be located on a patient relative to the insertion site S. 
         [0057]    Appliance  200  preferably separates cannula  20  from the epidermis E. According to one embodiment, wing  240  includes a thickness  246  between first surface  242  and second surface  244 . Preferably, thickness  246  provides a spacer that prevents or at least minimizes contiguous engagement between the epidermis E and hub  20   a  of cannula  20 . Wing  240  therefore preferably eliminates or at least reduces epidermal inflammation or breakdown, e.g., chafing or blistering, caused by cannula  20 . 
         [0058]    Wing(s)  240  preferably supplement the ability of appliance  200  to resist forces that tend to change the positions of electromagnetic spectrum sensor  1000  and cannula  20  relative to the epidermis E and the perivascular tissue P. Preferably, a skeleton of appliance  200  includes fitting  210 , frame  220 , and at least one wing rib  248 . Fitting  210  preferably interacts with electromagnetic spectrum sensor  1000  in a manner comparable to fitting  110  discussed above. Preferably, frame  220  includes a hoop  222  coupled with fitting  210  by at least one arm  224 . Thus, frame  220  may be comparable to frame  120  at least insofar as preferably contributing to distributing to the epidermis E the forces that act on fitting  210 . Appliance  200  preferably resists changes to the relative position between sensor face  1000   a  and the epidermis E by distributing over relatively large areas of the epidermis E the forces that may tend to move electromagnetic spectrum sensor  1000  in the first arrangement of fitting  210 . Individual wing ribs  248  preferably enlarge the area of the epidermis E over which frame  220  distributes forces acting on fitting  210 . According to one embodiment, individual wing ribs  248  preferably include a cantilever having a base coupled with frame  220  and a tip disposed in a corresponding wing  240 . According to other embodiments, more than one wing rib  248  may be disposed in a corresponding wing  240 , individual wing ribs  248  may include a bifurcated cantilever, and/or individual cantilevers may include one or more branches. The skeleton of appliance  200  therefore preferably enhances maintaining a substantially consistent relative position between electromagnetic spectrum sensor  1000  and the perivascular tissue P for sensing over time if fluid from cannula  20  is infusing the perivascular tissue P. 
         [0059]    Appliance  200  preferably is sufficiently flexible to conform to the approximate contours of the epidermis E. For example, frame  220  may include one or more lines of weakness disposed on hoop  222 , arm(s)  224  and/or wing rib(s)  248 . As the terminology is used herein, “lines of weakness” preferably refers to living hinges or other suitable features for increasing flexibility at a particular location of the skeleton of appliance  200 . 
         [0060]    Body  230  preferably presents a soft haptic exterior surface overlying the relatively rigid skeleton of appliance  200 . In a manner comparable to body  130  discussed above, body  230  is relatively supple, e.g., has a relatively lower hardness, and may be molded over fitting  210 , frame  220  and wing rib(s)  248 . According to one embodiment, body  230  preferably includes first surface  242 , at least a portion of second surface  244 , and a large portion of thickness  246 . The remaining portions of second surface  244  and thickness  246  preferably are occupied by wing rib(s)  248 . Accordingly, an individual wing  240  preferably is primarily composed of the relatively supple material of body  230  with wing rib(s)  248  included for force distribution and/or structural reinforcement. 
         [0061]    Preferably accompanying appliance  200  may be at least one independent contamination barrier  260  for overlying the epidermis E and at least a portion of cannula  20  while allowing visual inspection of the insertion site S.  FIG. 3  shows an exploded view with contamination barrier  260  displaced from appliance  200 . Contamination barrier  260  preferably is biocompatible according to ISO 10993 and/or USP Class VI and may include a polyurethane membrane  262  with a coating of medical grade acrylic adhesive  264 . Examples of typical contamination barriers include Tegaderm™, manufactured by 3M (St. Paul, Minn., USA), REACTIC™, manufactured by Smith &amp; Nephew (London, UK), and other transparent or translucent polymer films that are substantially impervious to solids, liquids, microorganisms and/or viruses. Preferably, contamination barrier  260  is supplied as a separate piece to appliance  200 —both pieces may be included in a kit—and the two pieces are independently coupled to the epidermis E at different times or in different steps. 
         [0062]    Appliance  200  and contamination barrier  260  preferably include form factors that cooperate with one another. According to one embodiment, body  230  preferably includes a form factor such as a flange  232  that covers hoop  222  and arm(s)  224 . Preferably, flange  232  includes a top surface  232   a  to which adhesive  264  may adhere membrane  262  when appliance  200  and contamination barrier  260  are used in combination. According to one embodiment, a set of individual contamination barriers  260  preferably accompanies each appliance  200 . Each of the contamination barriers  260  in the set preferably includes a notch  266  or another form factor having a peripheral edge that is sized and/or shaped to correspond with at least a portion of flange  232  and/or wing  240  on one or the other side of axis A. Accordingly, one or another of contamination barriers  260  in the set preferably is selected to apply to the epidermis E on the side of axis A that cannula  20  is located. According to other embodiments, contamination barrier  260  preferably includes a symmetrical shape that may be turned or otherwise reoriented to cooperatively engage appliance  200  on either side of axis A that cannula  20  is located. 
         [0063]    A method of using appliance  200  to monitor if fluid is infusing perivascular tissue around cannula  20  preferably includes (i) coupling appliance  200  to the epidermis E; (ii) coupling electromagnetic spectrum sensor  1000  in the first arrangement of fitting  210 ; and (iii) coupling cannula  20  with one wing  240 . Preferably, appliance  200  is coupled with the epidermis E by adhesive included in foundation  250  or by another suitable epidermal fastener. Electromagnetic spectrum sensor  1000  preferably is translated along axis A to the first arrangement of fitting  210  and securely latched. Preferably, one wing  240  underlays cannula  20  and an adhesive strip  270  (see  FIG. 4 ) secures cannula  20  to wing  240 . According to one embodiment, cannula  20  is inserted in the blood vessel V and then one wing  240  is positioned under cannula  20  before adhering appliance  200  to the epidermis E. Adhesive strip  270  subsequently overlies and couples cannula  20  with respect to wing  240  before coupling electromagnetic spectrum sensor  1000  in the first arrangement of fitting  210 . According to other embodiments, electromagnetic spectrum sensor  1000  is coupled in the first arrangement of fitting  210  before positioning one wing  240  under cannula  20  and adhering appliance  200  to the epidermis E. Adhesive strip  270  subsequently overlies and couples cannula  20  with respect to wing  240 . Each of the aforementioned embodiments may also include adhering contamination barrier  260  with top surface  232   a  of flange  232 , as well as with the epidermis E. Preferably, electromagnetic spectrum sensor  1000  may be moved between the first and second arrangements of fitting  210  without decoupling appliance  200  from the epidermis E, without decoupling cannula  20  or adhesive strip  270  from wing  240 , and without decoupling contamination barrier  260  from the epidermis E. 
         [0064]    Appliance  200  preferably is advantageous at least because (i) appliance  200  may be physically associated with a dressing for the IV insertion site S; (ii) appliance  200  links electromagnetic spectrum sensor  1000  and cannula  20 ; (iii) appliance  200  includes a plurality of locating options for linking electromagnetic spectrum sensor  1000  with respect to cannula  20 ; (iv) appliance  200  maintains a substantially consistent relative position between electromagnetic spectrum sensor  1000  and the perivascular tissue P for sensing over time if fluid from cannula  20  is infusing the perivascular tissue P; and (v) appliance  200  eliminates or at least reduces epidermal inflammation or breakdown caused by cannula  20 . 
         [0065]    Appliance  200  preferably also is advantageous insofar as preventing or minimizing forces that tend to distort the epidermis E while moving between the first and second arrangements of fitting  210 . It is believed that reducing distortion of the epidermis E reduces distortion of subcutaneous tissue including the perivascular tissue P and the blood vessel V, and therefore also reduces the likelihood of displacing cannula  20  while moving between the first and second arrangements of fitting  210 . 
         [0066]      FIGS. 6 and 7  show an embodiment of an appliance  300  that includes (i) a fitting  310  for receiving electromagnetic spectrum sensor  1000 , which senses if fluid is infusing perivascular tissue around cannula  20 ; (ii) a frame  320  for distributing forces acting on appliance  300  to the epidermis E; and (iii) a body  330  for covering fitting  310  and frame  320  with a soft haptic surface. As compared to appliances  100  and  200  ( FIGS. 1A-5B ), a first arrangement of fitting  310  preferably is an alternate to the first arrangements of fittings  110  and  210 ; however, the second arrangements of fittings  110 ,  210  and  310  preferably are similar insofar as releasing electromagnetic spectrum sensor  1000  from the respective first arrangements. Preferably, other features and advantages of appliances  100 ,  200  and  300  are comparable including (i) frames  120 ,  220  and  320 ; (ii) wings  240  and  340 ; (iii) wing ribs  248  and  348 ; (iv) bodies  130 ,  230  and  330 ; (v) foundations  150 ,  250  and  350 ; (vi) contamination barriers  260  and  360 ; and (vii) adhesive strips  270  and  370 . Appliance  300  preferably positions sensor face  1000   a  relative to the epidermis E within approximately five centimeters of the insertion site S and preferably approximately one centimeter to approximately three centimeters away from the insertion site S. 
         [0067]    The first arrangement of fitting  310  preferably includes sets of pegs for constraining relative movement between electromagnetic spectrum sensor  1000  and appliance  300 . As the terminology is used herein, “peg” preferably refers to a projecting piece or portion of a surface that is used as a support or boundary. According to one embodiment, fitting  310  includes a first set of pegs  312  disposed proximate sensor face  1000   a  and a second set of pegs  314  disposed proximate lead  1010 . Preferably, a cage of appliance  300  includes first and second sets of pegs  312  and  314 . The cage preferably defines a pocket for receiving electromagnetic spectrum sensor  1000  and constrains relative movement between electromagnetic spectrum sensor  1000  and appliance  300  in the first arrangement of fitting  310 . Preferably, first set of pegs  312 —two pegs are shown in FIG.  7 —preferably includes a form factor that generally conforms to the contours of electromagnetic spectrum sensor  1000  to define a first portion of the cage. Individual pegs  312  preferably include a cantilever extending between a base  312   a  and a tip  312   b . Preferably, base(s)  312   a  are coupled to frame  320  and tip(s)  312   b  at least slightly overlie electromagnetic spectrum sensor  1000  to constrain movement away from the epidermis E in the first arrangement of fitting  310 . According to one embodiment, individual pegs  312  preferably are bifurcated at base  312   a  and converge at tip  312   b.    
         [0068]    Second set of pegs  314 —two pegs are shown in FIG.  7 —preferably are disposed on opposite sides of electromagnetic spectrum sensor  1000  to define a second portion of the cage. Individual pegs  314  preferably include cantilevers extending between a base  314   a  and a tip  314   b . Preferably, bases  314   a  are coupled to frame  320  and a portion of electromagnetic spectrum sensor  1000  proximate lead  1010  is received between tips  314   b  to constrain relative angular movement and/or provide strain relief for electromagnetic spectrum sensor  1000  in the first arrangement of fitting  310 . 
         [0069]    Other embodiments of appliance  300  may have sets including different numbers, locations and shapes of pegs  312  and pegs  314 . For example, the first set may include more or less than two pegs  312 ; the second set may include more than a single peg  314  located on each side of electromagnetic spectrum sensor  1000 ; and/or tip  314   b  of at least one peg  314  may include a bump or other projection for retaining electromagnetic spectrum sensor  1000  in the first arrangement of fitting  310 . 
         [0070]    Body  330  preferably presents a soft haptic exterior surface overlying the relatively rigid fitting  310  and frame  320  of appliance  300 . In a manner comparable to bodies  130  and  230  discussed above, body  330  is relatively supple, e.g., has a relatively lower hardness, and may be molded over fitting  310 , frame  320  and wing rib(s)  348 . 
         [0071]    Appliance  300  preferably includes a link between electromagnetic spectrum sensor  1000  and cannula  20 . Preferably, appliance  300  includes at least one wing  340  coupled with at least one of fitting  310 , frame  320 , and body  330 . Individual wings  340  preferably are comparable to individual wings  240  of appliance  200  at least insofar as (i) locating electromagnetic spectrum sensor  1000  with respect to cannula  20 ; (ii) separating cannula  20  from the epidermis E; and/or (iii) providing resistance to forces that tend to change the position of electromagnetic spectrum sensor  1000  relative to the perivascular tissue P. 
         [0072]    Individual wings  340  of appliance  300  preferably separate cannula  20  from the epidermis E, and preferably supplement the ability of appliance  300  to resist forces that tend to change the position of electromagnetic spectrum sensor  1000  relative to the perivascular tissue P. Preferably, wing  340  includes a thickness  346  that eliminates or at least reduces epidermal inflammation or breakdown caused by cannula  20 . Preferably, a skeleton of appliance  300  includes fitting  310 , frame  320 , and at least one wing rib  348  to distribute to the epidermis E the forces that act on fitting  310 . Further, appliance  300  preferably resists changes to the relative position between sensor face  1000   a  and the epidermis E by distributing over relatively large areas of the epidermis E the forces that may tend to move electromagnetic spectrum sensor  1000  in the first arrangement of fitting  310 . Accordingly, appliance  300  is comparable at least in this regard to appliances  100  and  200  Individual wing ribs  348  preferably enlarge the area of the epidermis E over which frame  320  distributes forces acting on fitting  310 . The skeleton of appliance  300  therefore preferably enhances maintaining a substantially consistent relative position between electromagnetic spectrum sensor  1000  and the perivascular tissue P for sensing over time if fluid from cannula  20  is infusing the perivascular tissue P. 
         [0073]    Appliance  300  preferably is comparable to appliance  200  insofar as including plural locating options for linking electromagnetic spectrum sensor  1000  with respect to cannula  20 . Factors for selecting the most suitable locating option are discussed above with regard to appliance  200 . Appliance  300  also therefore includes the advantage of having more than one choice for how an anatomical sensor may be located on a patient relative to the insertion site S. 
         [0074]    A process for implementing appliance  300  to sense if fluid is infusing perivascular tissue around cannula  20  preferably includes (i) coupling appliance  300  to the epidermis E; (ii) coupling electromagnetic spectrum sensor  1000  in the first arrangement of fitting  310 ; and (iii) coupling cannula  20  with one wing  340 . A process for coupling electromagnetic spectrum sensor  1000  with appliance  300  preferably includes (i) orienting electromagnetic spectrum sensor  1000  obliquely with respect to frame  320 ; (ii) slipping electromagnetic spectrum sensor  1000  under tip(s)  312   a ; and (iii) pivoting electromagnetic spectrum sensor  1000  between peg(s)  314 . Accordingly, the cage including first and second sets of pegs  312  and  314  preferably constrains relative movement between electromagnetic spectrum sensor  1000  and appliance  300 . Preferably, the cage of appliance  300  includes. Preferably, the second arrangement of fitting  310  includes reversing the above process for coupling electromagnetic spectrum sensor  1000  with appliance  300 . Decoupling electromagnetic spectrum sensor  1000  in the second arrangement of fitting  310  accordingly permits reusing electromagnetic spectrum sensor  1000  in the same or a different appliance  300 . 
         [0075]    While the present invention has been disclosed with reference to certain embodiments, numerous modifications, alterations, and changes to the described embodiments are possible without departing from the sphere and scope of the present invention, as defined in the appended claims. For example, appliances  100 ,  200  and  300  preferably are devoid of materials, e.g., metal, that may harm a patient or damage diagnostic equipment during magnetic resonance imaging, computerized axial tomography, x-rays, or other procedures that use electromagnetic radiation. Advantageously, appliances  200  and  300  may be comparable to appliance  100  at least insofar as being also interchangeably useable with typical dressings for the IV insertion site S. Accordingly, it is intended that the present invention not be limited to the described embodiments, but that it has the full scope defined by the language of the following claims, and equivalents thereof.