Patent Publication Number: US-2013237779-A1

Title: Systems and Methods to Mitigate the Effects of Skin Moisture on a Percutaneous Infrared Signal

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     This application claims the priority of U.S. Provisional Application No. 61/681,231, filed 9 Aug. 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 
     Not Applicable 
     BACKGROUND OF THE INVENTION 
       FIG. 6  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 or infusate 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). 
     A cannula  20  is typically used for administering fluid via a subcutaneous blood vessel V. (See  FIG. 1 .) Typically, cannula  20  is inserted through epidermis E at a cannulation 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. 
     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. 
     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. 
     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. 
     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. 
     Intravenous infusion or therapy typically uses a fluid (e.g., infusate, whole blood, or blood product) to correct an electrolyte imbalance, to deliver a medication, or to elevate a fluid level. Typical infusates predominately consist of sterile water with electrolytes (e.g., sodium, potassium, or chloride), calories (e.g., dextrose or total parenteral nutrition), or medications (e.g., anti-infectives, anticonvulsants, antihyperuricemic agents, cardiovascular agents, central nervous system agents, chemotherapy drugs, coagulation modifiers, gastrointestinal agents, or respiratory agents). Examples of medications that are typically administered during intravenous therapy include acyclovir, allopurinol, amikacin, aminophylline, amiodarone, amphotericin B, ampicillin, carboplatin, cefazolin, cefotaxime, cefuroxime, ciprofloxacin, cisplatin, clindamycin, cyclophosphamide, diazepam, docetaxel, dopamine, doxorubicin, doxycycline, erythromycin, etoposide, fentanyl, fluorouracil, furosemide, ganciclovir, gemcitabine, gentamicin, heparin, imipenem, irinotecan, lorazepam, magnesium sulfate, meropenem, methotrexate, methylprednisolone, midazolam, morphine, nafcillin, ondansetron, paclitaxel, pentamidine, phenobarbital, phenytoin, piperacillin, promethazine, sodium bicarbonate, ticarcillin, tobramycin, topotecan, vancomycin, vinblastine and vincristine. Transfusions and other processes for donating and receiving whole blood or blood products (e.g., albumin and immunoglobulin) also typically use intravenous infusion. 
     Unintended infusing typically occurs when fluid from cannula  20  escapes from its intended vein/artery. Typically, unintended infusing causes an abnormal amount of the fluid to diffuse or accumulate in perivascular tissue 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. As the terminology is used herein, “perivascular tissue” preferably refers to the cells and/or interstitial compartments that are in the vicinity of a blood vessel and may become unintentionally infused with fluid from cannula  20 . 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.” 
     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, compartment syndrome, or necrosis. Typical treatment for infiltration or extravasation includes applying warm compresses, administering hyaluronidase, phentolamine, sodium thiosulfate or dexrazoxane, fasciotomy, or amputation. 
     BRIEF SUMMARY OF THE INVENTION 
     Embodiments according to the present invention include a system for aiding in diagnosing subcutaneous fluid leakage with a sensor that overlies a target area of epidermis. The system includes an antiseptic agent, an antiperspirant, and a foundation configured to couple the sensor and epidermis. The antiseptic agent is configured to clean the target area. The antiperspirant is configured to minimize moisture content variation of the target area. The foundation includes an adhesive. 
     Other embodiments according to the present invention include a system for monitoring an intravascular infusion. The system includes a sensor and antiperspirant. The sensor is configured to emit a first percutaneous electromagnetic signal and to receive a second percutaneous electromagnetic signal. The second percutaneous electromagnetic signal includes at least one of a reflection, scattering and diffusion of the first percutaneous electromagnetic signal. The antiperspirant is configured to be disposed at a target area of epidermis, and the first and second percutaneous electromagnetic signals pass through the target area. 
     Other embodiments according to the present invention include a system for monitoring an anatomical property of a body that includes an epidermis. The system includes a sensor and an antiperspirant. The sensor is configured to overlie a target area of the epidermis and to receive a first signal regarding the anatomical property. The antiperspirant is configured to minimize moisture content variation of the target area of the epidermis. 
     Other embodiments according to the present invention include a system for monitoring a subcutaneous anatomical property of a body that includes an epidermis. The system includes first and second sensors. The first sensor is configured to overlie a target area of the epidermis and to receive a first signal regarding the subcutaneous anatomical property. The second sensor is configured to receive a second signal regarding moisture content of the target area of the epidermis. 
     Other embodiments according to the present invention include a method of sensing fluid in perivascular tissue. The method includes applying an antiperspirant to a target area of epidermis and coupling a sensor to the epidermis. The sensor is configured to emit and detect near-infrared signals through the target area. 
     Other embodiments according to the present invention include a method of monitoring an anatomical property of a body including an epidermis. The method includes applying an antiperspirant to a target area of the epidermis and sensing at the target area a signal regarding the anatomical property. 
     Other embodiments according to the present invention include a method of monitoring an intravascular infusion. The method includes sensing fluid in perivascular tissue. Sensing the fluid includes detecting a first percutaneous near-infrared signal passing through a target area of epidermis. The method further includes sensing moisture content of the epidermis at the target area, and compensating the first percutaneous near-infrared signal based on the moisture content of the epidermis at the target area. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       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. 
         FIG. 1  is a schematic cross-section view illustrating an embodiment of an electromagnetic spectrum sensor according to the present disclosure. 
         FIGS. 2A-2D  illustrate examples of changes in percutaneous transmission of electromagnetic radiation that the inventors discovered are caused by moisture content variation of skin. 
         FIG. 3  is a flow chart illustrating an embodiment of a method according to the present disclosure for annulling epidermal moisture content variation. 
         FIG. 4A  is a schematic cross-section view illustrating an embodiment of a bi-spectral sensor according to the present disclosure to compensate for epidermal moisture content variation. 
         FIG. 4B  is a schematic illustration of a signal processing system including the bi-spectral sensor shown in  FIG. 4A . 
         FIG. 5A  is a schematic cross-section view illustrating an embodiment of a combination sensor according to the present disclosure to compensate for epidermal moisture content variation. 
         FIG. 5B  is a schematic illustration of a signal processing system including the combination sensor shown in  FIG. 5A . 
         FIG. 6  is a schematic view illustrating a typical set-up for infusion administration. 
     
    
    
     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 
     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. 
     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. 
     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. 
     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. 
       FIG. 1  shows an electromagnetic spectrum sensor  1000  preferably coupled with the epidermis E. Preferably, electromagnetic spectrum sensor  1000  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. 
     Electromagnetic spectrum sensor  1000  includes a sensor face  1000   a  preferably arranged to confront or overlie a target area of the epidermis E for aiding in diagnosing infiltration or extravasation. As the terminology is used herein, “target area” preferably refers to a portion of a patient&#39;s epidermis that is generally proximal to where an infusate is being administered and frequently proximal to the cannulation site S. Preferably, electromagnetic radiation  1002  is emitted via sensor face  1000   a  and received electromagnetic radiation  1004  is received via sensor face  1000   a . Emitted electromagnetic radiation  1002  preferably passes through the target area of the epidermis E into perivascular tissue P. Preferably, infiltration or extravasation of the perivascular tissue P by an infusate fluid affects the absorption of emitted electromagnetic radiation  1002 . Received electromagnetic radiation  1004  preferably includes at least a portion of emitted electromagnetic radiation  1002  that is reflected, scattered, diffused, or otherwise redirected from the perivascular tissue P and/or infusate fluid, through the target area of the epidermis E, to sensor face  1000   a . Accordingly, infiltration or extravasation of the perivascular tissue P with the infusate fluid preferably also affects received electromagnetic radiation  1004 . Electromagnetic spectrum sensor  1000  therefore preferably detects changes in received electromagnetic radiation  1004  that correspond with anatomic changes over time due to accumulation of infusate fluid in the perivascular tissue P. Acute limb compartment syndrome is an example of such an anatomic change. 
     Emitted and received electromagnetic radiations  1002  and  1004  preferably are in the near-infrared portion of the electromagnetic spectrum. As the terminology is used herein, “near infrared” preferably refers to electromagnetic radiation having wavelengths between approximately 750 nanometers and approximately 1,400 nanometers. These wavelengths correspond to a frequency range of approximately 400 terahertz to approximately 215 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 about a single wavelength, e.g., approximately 970 nanometers (approximately 309 terahertz). According to other embodiments, emitted electromagnetic radiation  1002  includes a set of wavelengths 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 set of wavelengths in a band between a relatively low wavelength and a relatively high wavelength, and emitted electromagnetic radiation  1002  encompasses at least the band between the relatively low and high wavelengths. 
     Electromagnetic spectrum sensor  1000  preferably is positioned in close proximity to the epidermis E. As the terminology is used herein, “close proximity” of electromagnetic spectrum sensor  1000  and the epidermis E preferably refers to a relative arrangement that substantially eliminates gaps between sensor face  1000   a  and the epidermis E. According to one embodiment, sensor face  1000   a  preferably contiguously engages the epidermis E. According to other embodiments, a foundation  100  preferably is disposed between electromagnetic spectrum sensor  1000  and the epidermis E. Preferably, sensor face  1000   a  contiguously engages foundation  100  and foundation  100  contiguously engages the epidermis E. 
     Foundation  100  preferably includes a panel  102  and/or adhesive  104  coupled with respect to sensor face  1000   a . Preferably, panel  102  separates electromagnetic spectrum sensor  1000  from the epidermis E. Panel  102  preferably includes Tegaderm™, manufactured by 3M (St. Paul, Minn., USA), REACTIC™, manufactured by Smith &amp; Nephew (London, UK), or another transparent or translucent polymer film that is substantially impervious to solids, liquids, microorganisms and/or viruses. Preferably, panel  102  is biocompatible and generally transparent with respect to emitted and received electromagnetic radiations  1002  and  1004 . 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. 
     Adhesive  104  preferably bonds at least one of electromagnetic spectrum sensor  1000  and panel  102  to the epidermis E. Adhesive  104  preferably includes an acrylic adhesive or another medical grade, biocompatible adhesive. Preferably, adhesive  104  minimally affects the transmission of emitted and received electromagnetic radiations  1002  and  1004 . According to one embodiment, adhesive  104  preferably is omitted where emitted and received electromagnetic radiations  1002  and  1004  penetrate foundation  100 . 
     The inventors discovered a problem regarding percutaneous electromagnetic radiation measurements and inaccurate indications of infiltration/extravasation events. In particular, a problem that the inventors discovered is that some changes in the amount of received electromagnetic radiation  1004  are unrelated to the occurrence of infiltration or extravasation. The inventors discovered that these changes generally occur during an approximately 60-minute period of time that begins with positioning electromagnetic spectrum sensor  1000  in close proximity to the epidermis E. The inventors further discovered that these changes predominately include a drop in the amount of received electromagnetic radiation  1004  that occurs within an approximately 35-minute period of time. The inventors also discovered that these changes occur frequently but inconsistently in a statistically significant patient population. In particular, the inventors discovered that these changes occur in approximately 65% to approximately 85% of patient populations. Thus, the inventors discovered, inter alio, that there is a problem because some changes in the amount of received electromagnetic radiation  1004  do not correlate with occurrences of infiltration/extravasation events. 
     The inventors also discovered that a source of the problem is moisture content variations of the epidermis E due to, for example, secretion or evaporation of sweat. In particular, the inventors discovered that the source of some changes in the amount of received electromagnetic radiation  1004  is epidermal moisture at least partially mimicking the electromagnetic radiation absorption of an infusate fluid. Thus, the inventors discovered, inter alio, that moisture content variation in the epidermis E affects the amount of received electromagnetic radiation  1004 . 
     The inventors further discovered that moisture content variation of the epidermis E is a source of unreliable measurements by epidermal sensors. As the terminology is used herein, “epidermal sensors” preferably refer to (i) sensors that measure thermal properties, e.g., temperature or heat flux, of the epidermis E; (ii) sensors that measure electrical properties, e.g., resistance or impedance, of the epidermis E; (iii) sensors that measure transmission and/or reflectance of electromagnetic radiation, e.g., visible light or infrared radiation, with respect to the epidermis E or perivascular tissue P; or (iv) sensors that measure other properties or quantities of/through the epidermis E. According to one embodiment, unreliable measurements by epidermal sensors may result in inaccurate indications that an infiltration/extravasation event has occurred. The inventors also discovered that epidermal sensor measurements are affected during periods of time that generally coincide with the moisture content of the epidermis E achieving equilibrium. As the terminology is used herein, “equilibrium” of the moisture content of the epidermis E preferably refers to a generally steady-state overall in the production, transfer and loss of moisture content by/from the epidermis E. The inventors further discovered that the period of time for achieving equilibrium predominantly begins shortly after positioning epidermal sensors in close proximity to the epidermis E; however, other periods of time for achieving equilibrium may begin some time later while the epidermal sensor is still positioned in close proximity to the epidermis E. The inventors additionally discovered that the period of time for achieving equilibrium is generally finite, e.g., equilibrium of the moisture content of the epidermis E is generally achieved in approximately 60 minutes or less and frequently in approximately 35 minutes or less. Thus, the inventors discovered, inter alio, that moisture content variation in the epidermis E is a source of unreliable measurements by epidermal sensors. 
       FIGS. 2A-2D  illustrate examples of unreliable measurements by epidermal sensors due to moisture content variations of the epidermis E.  FIG. 2A  illustrates a first example in which there is a first relatively high amount R 1  of received electromagnetic radiation  1004  approximately when electromagnetic spectrum sensor  1000  is initially coupled to the epidermis E. The inventors discovered that the amount of received electromagnetic radiation  1004  begins to fall thereafter, e.g., during an approximately 35-minute period of time, and that the fall corresponds to an increase in the moisture content of the epidermis E. Increasing moisture content from a generally depressed level may be due to, for example, (i) patient anxiety; or (ii) interference with normal perspiration and evaporation processes because electromagnetic spectrum sensor  1000  is positioned in close proximity to the epidermis E. Heightened levels of epidermal moisture predominantly correspond to more absorption of emitted electromagnetic radiation  1002 . Accordingly, an increase in the moisture content of the epidermis E generally causes a fall in the amount of received electromagnetic radiation  1004  because there is more absorption of emitted electromagnetic radiation  1002 . The inventors further discovered that the fall in received electromagnetic radiation  1004  generally continues until the moisture content of the epidermis E achieves equilibrium; whereupon a first relatively low amount R 2  of received electromagnetic radiation  1004  may remain generally consistent until and unless an infiltration/extravasation event occurs as shown with the broken line in  FIG. 2A . Predominately, emitted electromagnetic radiation  1002  is also absorbed during the infiltration/extravasation event as fluid, e.g., an infusate or blood, accumulates in the perivascular tissue P. Accordingly, there is a second relatively low amount R 3  of received electromagnetic radiation  1004  that is caused by fluid accumulation in the perivascular tissue P rather than by moisture content variation in the epidermis E, which was the cause of the first relatively low amount R 2  of received electromagnetic radiation  1004 . Thus, the inventors discovered, inter alio, that moisture content variation of the epidermis E may be mistaken for an infiltration/extravasation event because a first fall (R 1  to R 2 ) in the amount of received electromagnetic radiation  1004  when the moisture content of the epidermis E is achieving equilibrium may be similar to a second fall (R 2  to R 3 ) in the amount of received electromagnetic radiation  1004  when an infiltration/extravasation event is occurring. 
       FIG. 2B  illustrates a second example in which there is a first relatively low amount R 4  of received electromagnetic radiation  1004  approximately when electromagnetic spectrum sensor  1000  is initially coupled to the epidermis E. The inventors discovered that the amount of received electromagnetic radiation  1004  begins to rise thereafter and that the rise corresponds to a decrease in the moisture content of the epidermis E. Decreasing moisture content from a generally heightened level may be due to, for example, (i) environmental factors such as cold, dry air; (ii) surgery; (iii) bathing; or (iv) interference with normal perspiration and evaporation processes because electromagnetic spectrum sensor  1000  is positioned in close proximity to the epidermis E. Depressed levels of epidermal moisture predominantly correspond to less absorption of emitted electromagnetic radiation  1002 . Accordingly, a decrease in the moisture content of the epidermis E generally causes a rise in the amount of received electromagnetic radiation  1004  because there is less absorption of emitted electromagnetic radiation  1002 . The inventors further discovered that the rise in received electromagnetic radiation  1004  generally continues until the moisture content of the epidermis E achieves equilibrium; whereupon a first relatively high amount R 5  of received electromagnetic radiation  1004  may remain generally consistent until and unless an infiltration/extravasation event occurs as shown with the broken line in  FIG. 2B . During the infiltration/extravasation event, a second relatively high amount R 6  of received electromagnetic radiation  1004  may be associated with reduced electromagnetic radiation absorption when fluid accumulates in the perivascular tissue P rather than moisture content variation in the epidermis E, which was the cause of the first relatively high amount R 5  of received electromagnetic radiation  1004 . It is believed that reduced absorption of electromagnetic radiation may be associated with certain wavelengths and/or the electromagnetic spectral signature of certain infusate fluids. As the terminology is used herein, “spectral signature” preferably refers to a pattern of reflected and absorbed electromagnetic wavelengths that particularly corresponds to and therefore identifies a material. Thus, the inventors discovered, inter alio, that moisture content variation of the epidermis E may be mistaken for an infiltration/extravasation event because a first rise (R 4  to R 5 ) in the amount of received electromagnetic radiation  1004  when the moisture content of the epidermis E is achieving equilibrium may be similar to a second rise (R 5  to R 6 ) in the amount of received electromagnetic radiation  1004  when an infiltration/extravasation event is occurring. 
       FIGS. 2C and 2D  illustrate additional examples in which a change in received electromagnetic radiation  1004  due to moisture content variations of the epidermis E occurs some time after coupling electromagnetic spectrum sensor  1000  to the epidermis E. The inventors discovered that changes in received electromagnetic radiation  1004  may correspond to increasing ( FIG. 2C ) or decreasing ( FIG. 2D ) moisture content of the epidermis E that occurs some time after an initial period of time for achieving equilibrium. Thus, the inventors further discovered, inter alio, that a moisture content variation of the epidermis E that occurs some time after equilibrium is initially achieved may be mistaken for an infiltration/extravasation event. The examples in  FIGS. 2A-2D  therefore illustrate that measurements by epidermal sensors typically may be unreliable because moisture content variations of the epidermis E may be mistaken for infiltration/extravasation events. 
       FIG. 3  illustrates an embodiment of a method  200  to substantially achieve equilibrium of the epidermis E by annulling the effects of epidermal moisture content variation. As the terminology is used herein, “annulling” of epidermal moisture content variation preferably refers to eliminating or substantially assuaging variations in the moisture content of the epidermis E. Method  200  preferably begins when a target area of the epidermis E that is to be overlaid by sensor face  1000   a  is identified  202 . Preferably, method  200  includes preparation  210  of the target area of the epidermis E. According to one embodiment, target area preparation  210  preferably includes target area cleaning  212 , target area treating  214 , and target area protecting  216 . Preferably, target area cleaning  212  includes wiping the target area of the epidermis E with a pad soaked with an antiseptic agent such as a solution of approximately 70% isopropyl alcohol/30% deionized water. Other topical applicators and/or antiseptic cleaning agents may be used for target area cleaning  212 . Preferably, target area treating  214  includes applying an antiperspirant to the target area. Examples of antiperspirants preferably include those with aluminum-based active ingredients (e.g., aluminum chloride, aluminum zirconium, aluminum chlorohydrate, or aluminum hydroxybromide) or those with aluminum-free active ingredients (e.g., crystal alum or talc). Applying the antiperspirant to the target area of the epidermis E preferably includes wiping with a pad, rolling with a ball, spreading a solid, dousing a powder, or other suitable application techniques. Preferably, target area protecting  216  includes coating the epidermis with a biocompatible barrier film that, for example, minimizes skin trauma, enhances adhesively coupling electromagnetic spectrum sensor  1000  or foundation  100  with respect to the epidermis E, and/or facilitates subsequent decoupling of electromagnetic spectrum sensor  1000  or foundation  100  with respect to the epidermis E. Examples of barrier films preferably include Cavilon™, manufactured by 3M (St. Paul, Minn., USA), or Skin-Prep™, manufactured by Smith &amp; Nephew (London, UK). Thus, according to one embodiment of method  200 , target area preparation  210  preferably includes target area cleaning  212 , target area treating  214 , and target area protecting  216 . According to other embodiments, method  200  preferably includes target area treating  214  but may omit target area cleaning  212  and/or target area protecting  216 . Preferably, method  200  also includes coupling  204  electromagnetic spectrum sensor  1000  with the target area of the epidermis E and activating  206  electromagnetic spectrum sensor  1000 . 
     Target area treating  214  with an antiperspirant preferably annuls the source of the problem discovered by the inventors. Typically, antiperspirants have an astringent action that tends to reduce the size of skin pores and therefore halt or substantially reduce the passage of moisture via sweat gland ducts. Halting or substantially reducing the passage of moisture via sweat gland ducts preferably eliminates or substantially minimizes epidermal moisture content variations for achieving equilibrium of the epidermis E. Accordingly, target area treating  214  with an antiperspirant preferably annuls epidermal moisture content variation so that measurements with electromagnetic spectrum sensor  1000  may be relied on, for example, as an aid to diagnosing the occurrence of an infiltration/extravasation event. 
     Target area treating  214  with an antiperspirant preferably occurs no later than when electromagnetic spectrum sensor  1000  is coupled with the epidermis E. According to one embodiment of method  200 , target area treating  214  preferably occurs before coupling electromagnetic spectrum sensor  1000  with the epidermis E. Preferably, target area treating  214  occurs after target area cleaning  212  and before target area protecting  216 . Other embodiments according to method  200  preferably combine target area treating  214  with coupling electromagnetic spectrum sensor  1000  to the epidermis E. Preferably, foundation  100  includes a mixture of an antiperspirant and adhesive  104  for substantially concurrent target area treating  214  and electromagnetic spectrum sensor  1000  coupling to the epidermis E. Examples of mixtures for foundation  100  may include 1 to 99.9 weight percent adhesive formulation (e.g., elastomers that cure by hydrosilylation or condensation, pressure sensitive adhesives, or other biocompatible adhesives) and 0.1 to 50 weight percent antiperspirant (e.g., anti-diaphoretic compositions that may include aluminum-based active ingredients or aluminum-free active ingredients). Wax or other ingredients may also be included in mixtures for foundation  100 . 
       FIGS. 4A-5B  illustrate embodiments of a system  1100  for adjusting a percutaneous signal based on a cutaneous signal to compensate for the effects of epidermal moisture content variation.  FIG. 4A  shows system  1100  including a bi-spectral sensor  1110  coupled with the epidermis E for (i) aiding in diagnosing infiltration or extravasation; and (ii) measuring moisture content variation of the epidermis E. Aiding in diagnosing infiltration or extravasation preferably includes a first electromagnetic radiation  1002  that is emitted via a sensor face  1110 a of bi-spectral sensor  1110  and a first electromagnetic radiation  1004  that is received via sensor face  1110 a. First emitted and first received electromagnetic radiations  1002  and  1004  of bi-spectral sensor  1110  are generally similar to emitted and received electromagnetic radiations  1002  and  1004  of electromagnetic spectrum sensor  1000  shown in  FIG. 1 . For example, first emitted and first received electromagnetic radiations  1002  and  1004  preferably are percutaneous signals in the near-infrared portion of the electromagnetic spectrum. 
     Measuring the moisture content of the epidermis E preferably includes a second electromagnetic radiation  1102  that is emitted via sensor face  1110   a  and a second electromagnetic radiation  1104  that is received via sensor face  1110   a . Second emitted electromagnetic radiation  1102  preferably impinges on the epidermis E and second received electromagnetic radiation  1104  is at least a portion of second emitted electromagnetic radiation  1102  that is reflected, scattered, diffused, or otherwise redirected from the epidermis E to sensor face  1110   a . Preferably, second emitted and second received electromagnetic radiations  1102  and  1104  are cutaneous signals and the magnitude of second received electromagnetic radiation  1104  correlates with the moisture content of the epidermis E. 
     System  1100  preferably uses different portions of the electromagnetic spectrum for aiding in diagnosing infiltration/extravasation events and for measuring moisture content variation of the epidermis E. Preferably, second emitted and second received electromagnetic radiations  1102  and  1104  are in the visible light portion of the electromagnetic spectrum. As the terminology is used herein, “visible light” preferably refers to energy in the visible portion of the electromagnetic spectrum, for example, wavelengths between approximately 390 nanometers and approximately 750 nanometers. These wavelengths correspond to a frequency range of approximately 770 terahertz to approximately 400 terahertz. Preferably, second emitted and second received electromagnetic radiations  1102  and  1104  are tuned to a common peak wavelength. According to one embodiment, second emitted and second received electromagnetic radiations  1102  and  1104  preferably have a peak centered about a single wavelength, e.g., approximately 680 nanometers (approximately 440 terahertz). 
     Second received electromagnetic radiation  1104  preferably is used to compensate first received electromagnetic radiation  1004  for the effects of moisture content variation of the epidermis E. Preferably, second received electromagnetic radiation  1104  is a measure of the moisture content of the epidermis E and is used to compensate first received electromagnetic radiation  1004  in order to mitigate the effect of moisture content variation of the epidermis E, which is the source of the problem that the inventors discovered. Accordingly, the reliability of measurements made with bi-spectral sensor  1100  for aiding in diagnosing if an infiltration/extravasation event has occurred preferably is improved. 
       FIG. 4B  shows system  1100  preferably includes a processor  1120  running an algorithm that mitigates the effect of epidermal moisture content variations when aiding in diagnosing if an infiltration/extravasation event has occurred. Preferably, processor  1120  receives first received electromagnetic radiation  1004  and second received electromagnetic radiation  1104 . Processor  1120  preferably analyzes second received electromagnetic radiation  1104  to determine if there is epidermal moisture content variation and, if so, whether it is decreasing from a generally heightened level or increasing from a generally depressed level. Preferably, processor  1120  compensates first received electromagnetic radiation  1004  as necessary based on the analysis of second received electromagnetic radiation  1104 . Accordingly, changes in first received electromagnetic radiation  1004  that are due to moisture content variations of the epidermis E, which is the source of the problem that the inventors discovered, preferably may be mitigated to make system  1100  more reliable for aiding in diagnosing if an infiltration/extravasation event has occurred. 
       FIG. 5A  shows a system  1200  including a combination sensor  1210  coupled with the epidermis E for (i) aiding in diagnosing infiltration or extravasation; and (ii) measuring moisture content variation of the epidermis E. Aiding in diagnosing infiltration or extravasation preferably includes electromagnetic radiation  1002  that is emitted via a sensor face  1210   a  of combination sensor  1210  and electromagnetic radiation  1004  that is received via sensor face  1210   a . Preferably, emitted and received electromagnetic radiations  1002  and  1004  of combination sensor  1210  and of electromagnetic spectrum sensor  1000  ( FIG. 1 ) are generally similar. For example, emitted and received electromagnetic radiations  1002  and  1004  of both sensors preferably include percutaneous signals in the near-infrared portion of the electromagnetic spectrum. 
     Measuring epidermal moisture content with combination sensor  1210  preferably includes measuring at least one cutaneous property that correlates with the moisture content of the epidermis E. Preferably, combination sensor  1210  includes a probe  1212  for measuring an electrical property of the epidermis E. According to one embodiment, probe  1212  preferably includes an anode  1212   a  and a cathode  1212   b  that contiguously engage individual points of the epidermis E. Preferably, anode  1212   a  and cathode  1212   b  measure resistance, impedance, capacitance, inductance or another electrical property of the epidermis E that correlates with the moisture content of the epidermis E. According to other embodiments, probe  1212  may measure a change in an electrical or magnetic field that correlates with variations in the moisture content of the epidermis E. 
     The output of probe  1212  preferably is used to compensate received electromagnetic radiation  1004  for the effects of moisture content variation of the epidermis E. Preferably, measurements by probe  1212  correlate with moisture content variations of the epidermis E and the output of probe  1212  is used to compensate received electromagnetic radiation  1004  in order to mitigate the effect of moisture content variation of the epidermis E, which is the source of the problem that the inventors discovered. Accordingly, the reliability of measurements made with combination sensor  1210  for aiding in diagnosing if an infiltration/extravasation event has occurred preferably is improved. 
       FIG. 5B  shows system  1200  preferably includes a processor  1220  running an algorithm that mitigates the effect of epidermal moisture content variations when aiding in diagnosing if an infiltration/extravasation event has occurred. Preferably, processor  1220  receives received electromagnetic radiation  1004  and the output of probe  1212 . Processor  1220  preferably analyzes the output of probe  1212  to determine if there is epidermal moisture content variation and, if so, whether it is decreasing from a generally heightened level or increasing from a generally depressed level. Preferably, processor  1220  compensates received electromagnetic radiation  1004  as necessary based on the analysis of the output of probe  1212 . Accordingly, changes in received electromagnetic radiation  1004  that are due to moisture content variations of the epidermis E, which is the source of the problem that the inventors discovered, preferably may be mitigated to make system  1200  more reliable for aiding in diagnosing if an infiltration/extravasation event has occurred. 
     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, emitted and received electromagnetic radiations  1002  and  1004  may be centered about a peak wavelength at which the effect of cutaneous moisture may be generally insignificant as compared to subcutaneous fluid. According to one embodiment, electromagnetic radiation preferably is centered about a peak wavelength that is readily absorbed by a common constituent in both sweat and infusates. Water, which is an example of such a constituent, is readily absorbed in a band of wavelengths from approximately 940 nanometers to approximately 970 nanometers (approximately 319 terahertz to approximately 309 terahertz). With regard to received electromagnetic radiation  1004  in this band, changes due to sweat may be insignificant as compared to changes due to infiltration/extravasation because the volume of moisture at the epidermis E may be relatively small as compared to the volume of fluid in the perivascular tissue P. Accordingly, an aid to indicate an infiltration/extravasation event preferably is based on changes in electromagnetic radiation  1004  that exceed a selected threshold such that changes in electromagnetic radiation  1004  below the selected threshold may be disregarded as being due to, for example, epidermal moisture content variations. 
     According to another example, the intensity of emitted electromagnetic radiation  1002  may be selected or varied so as to render the effect of cutaneous moisture generally insignificant as compared to the effect of subcutaneous fluid. Based again on water being a common constituent in both infusates and sweat, a relatively larger volume of water in the perivascular tissue P during an infiltration/extravasation event generally has a greater limit to absorb emitted electromagnetic radiation  1002  as compared to a relatively smaller volume of water at the epidermis E due to sweat. Preferably, the intensity of emitted electromagnetic radiation  1002  is selected to be greater than that which can be absorbed by epidermal moisture and less than that which can be absorbed by perivascular fluid. Accordingly, received electromagnetic radiation  1004  preferably is sensitive to subcutaneous fluid changes as an aid to indicate an infiltration/extravasation event and relatively insensitive to cutaneous moisture variations, which are generally less significant because emitted electromagnetic radiation  1002  saturates epidermal moisture, e.g., sweat. 
     According to a further example, electromagnetic spectrum sensor  1000  preferably differentiates between the spectral signatures of sweat and infusates as an aid in diagnosing an infiltration/extravasation event. Preferably, distinguishing between the spectral signatures of subcutaneous fluid and cutaneous moisture facilitates mitigating the effect of epidermal moisture content variations on received electromagnetic radiation  1004 . Accordingly, electromagnetic spectrum sensor  1000  preferably provides an aid to indicate an infiltration/extravasation event has occurred based on detecting the spectral signature of the infusate in the perivascular tissue P. 
     While the present invention has been disclosed with reference to annulling or compensating for variations in moisture content of the epidermis to make percutaneous electromagnetic radiation measurements reliable, other mitigating systems and methods are possible to aid in diagnosing subcutaneous fluid leakage, monitoring an intravascular infusion, or monitoring over time changes in an anatomical property. For example, extenuating or palliating variations in moisture content of the epidermis may also make percutaneous electromagnetic radiation measurements more reliable. Thus, 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.