Abstract:
In accordance with one embodiment of the present invention, the invention comprises a pliable enclosure containing a Phase Change Material (PCM) that maintains a nearly constant predetermined temperature while transmitting heat during phase change. The predetermined temperature is maintained which the PCM absorbs heat from the body of the patient, thus maintain the patient&#39;s body temperature at a nearly constant predetermined temperature for as long as the PCM material is transitioning phase. The pliable enclosure, which in an embodiment forms an enclosed volume, may be comprised of a shell which contains the PCM. The shell may be fabricated from polyethylene, polyurethane, or any other pliable material and may further comprise graphene covering on at least one of its surfaces to provide a tough exterior that is resistant to puncture by, for example, hypodermic needles, suture needles, scalpels, or other sharp instruments.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS AND INCORPORATION BY REFERENCE 
       [0001]    This non-provisional patent application is a non-provisional of, and claims benefit of priority to, U.S. provisional patent application Ser. No. 62/250,922 filed in the United States Patent and Trademark Office (USPTO) on Nov. 4, 2015, titled PHASE CHANGE MATERIAL TEMPERATURE CONTROL DEVICE, SYSTEM AND METHOD, which is hereby incorporated herein by reference in its entirety. 
     
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
       [0002]    Not applicable. 
       INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISK 
       [0003]    Not applicable. 
       BACKGROUND OF THE INVENTION 
       [0004]    1. Field of the Invention 
         [0005]    The field of the invention relates generally to devices, systems and methods for maintaining a body of a person or object within a desired temperature range using phase change materials and methods. In an embodiment, the invention relates to devices, systems and methods for warming a body of a person. In an exemplary embodiment, the device, system and method of the invention may be utilized to maintain the body of a person at a constant desired and predetermined temperature while that person undergoes medical treatment, such as surgery, in which the immediate environment may be at a temperature that is uncomfortably cool for the patient, or while the patient is undergoing anesthesia, both of which tend to reduce the body temperature of the person. Thus the field of the invention is generally directed to thermoregulation of a body or other object using phase change materials and methods. 
         [0006]    2. Background Art 
         [0007]    The loss of body heat during surgery, and especially while a patient is undergoing anesthesia, can have negative consequences for a patient. Even mild hypothermia can be dangerous for patients. The consequences of even a few degrees Fahrenheit (Celsius) reduction in temperature include increased blood loss and transfusion requirement, surgical wound infection, and prolonged hospitalization and recovery. Studies have shown that virtually all surgical patients become hypothermic during surgery. Surgery patients are at risk for hypothermia due to exposure of large body surfaces for extended periods of time in a cool operating room. Patients who are anesthetized lose their ability to shiver, which is the body&#39;s natural way to attempt to correct hypothermia. Keeping patients warm reduces wound infection rates, decreases the likelihood of myocardial infarction, reduces mortality rates and can shorten the amount of time patients spend in the intensive care unit for post-operative care, and thus reduces their overall length of stay in a hospital or other health care facility. 
         [0008]    One solution that has been used to combat hypothermia in surgical patients is the use of forced air warming gowns, which force warmed air around the body of a patient within a gown worn by the patient. Another solution that has been used to combat hypothermia in surgical patients is the use of forced air warming blankets, which circulates warm air in and through a pliable enclosure upon which the patient lies. A still further solution is the use of electric warming blankets. 
         [0009]    However, these systems of the prior are difficult to regulate for temperature control, require electric power, are prone to failure due to the nature of the electromechanical systems used to force warmed air, spread infection by distributing airborne microorganisms around the body of a patient (in the case of the forced air warming gown), or are prone to puncture (in the case of the forced air warming blanket). Electric warming blankets require electric power, represent an electric shock hazard and complicate the surgical theater by requiring electric current supply cords and connections. 
         [0010]    What is needed in the art, therefore, is a device, system and method for warming the body of a person, for example a person undergoing anesthesia during surgery. 
       BRIEF SUMMARY OF THE INVENTION 
       [0011]    The present invention comprises an apparatus and method that have one or more of the following features and/or steps, which alone or in any combination may comprise patentable subject matter. 
         [0012]    The present invention overcomes the shortcomings of the prior art in that it eliminates the need for electromechanical components for controlling the temperature of a body, is reusable due to its ability to be sterilized, does not spread infection by distributing airborne microorganisms around the body of a patient, is easily temperature controlled, and does not require electric power. 
         [0013]    In accordance with one embodiment of the present invention, the invention comprises a pliable enclosure containing a Phase Change Material (PCM) that maintains a nearly constant predetermined temperature while absorbing or yielding up heat during a phase transition. The predetermined phase transition temperature is maintained which the PCM absorbs heat from, or supplies heat to, the body of a patient or other object, thus maintaining the patient&#39;s body or object temperature at a nearly constant predetermined temperature for as long as the PCM material is transitioning phase. 
         [0014]    The pliable enclosure, which in an embodiment forms an enclosed volume, may be comprised of a shell which contains the PCM. The shell may be fabricated from plastics such as polyethylene, polyurethane, or any other pliable material and may further comprise graphene covering on at least one of its surfaces to provide a tough exterior that is resistant to puncture by, for example, hypodermic needles, suture needles, scalpels, or other sharp instruments. 
         [0015]    The phase change material temperature control device, system and method of the invention is impervious to most solvents, and is rechargeable and reusable. 
         [0016]    In an embodiment of the phase change material temperature control pad intended for use in warming patients during surgery, the phase change material changes phase at a predetermined temperature between 90° Fahrenheit (32.222° Celsius) and 110° Fahrenheit (43.333° Celsius). In a still further preferred embodiment, the phase change material of the invention changes phase at 95° Fahrenheit (35° Celsius). The PCM may be selected such that any desired phase transition temperature may be achieved. 
         [0017]    In an embodiment, the invention may further comprise a carrier that provides a platform for receiving a phase change material temperature control pad of the invention, and upon which a person may lie while being warmed by the phase change material temperature control pad of the invention. Such a carrier may be useful in numerous applications, one of which is during a surgical operation. In such a situation the body of a person is disposed upon a phase change material temperature control pad of the invention which is received by the carrier while the PCM is undergoing phase transition, thus creating a stable platform upon which a person may lie while their temperature is being controlled. 
         [0018]    The phase change material warming pad in its broadest application has numerous applications and thus the claims and scope of the invention is not be construed as limited to only surgical applications. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]    The accompanying drawings, which are incorporated into and form a part of the specification, illustrate one or more embodiments of the present invention and, together with the description, serve to explain the principles of the invention. The drawings are only for the purpose of illustrating the preferred embodiments of the invention and are not to be construed as limiting the invention. In the drawings: 
           [0020]      FIG. 1  depicts a cross section of a phase change material temperature control pad of an exemplary embodiment of the invention, depicting the phase change material captured within the pliable enclosure enclosed volume, and depicting an embodiment of the graphene covering overlying a portion of the pliable enclosure. 
           [0021]      FIG. 2A  depicts a perspective view of an embodiment of the carrier and phase change material temperature control pad, showing the placement of the change material temperature control pad into the carrier. 
           [0022]      FIG. 2B  depicts an end view of the carrier and phase change material temperature control pad of an exemplary embodiment of the invention, showing the placement of the change material temperature control pad into the carrier. 
           [0023]      FIG. 3  depicts an exemplary embodiment of the invention placed on a surgical table for warming a patient, further showing a patient disposed upon the phase change material temperature control pad of an embodiment of the invention. 
           [0024]      FIG. 4  depicts an exemplary embodiment of the carrier of the invention, in which the carrier comprises an expanded weave of plastic material comprised of plastic wire, which may be further defined as stiff plastic wire, and wherein the expanded weave of plastic wire acts as a compressible structure, covered by a covering such as vinyl. 
           [0025]      FIG. 5  depicts a flow diagram of an exemplary method of the invention for controlling the temperature of the body of a patient undergoing medical treatment, which may include anesthesia, including the steps of determining a desired temperature to apply to the body of a person; selecting temperature control pad covering material and thickness, and determining the temperature control pad covering material and graphene coating thermal resistance; selecting PCM material for use in the temperature control pad for maintaining a constant pad temperature; providing a temperature control pad comprising the selected PCM enclosed within the selected temperature control pad covering material and thickness; charging the PCM material to a desired temperature; and causing a body of a person to be disposed upon the temperature control pad of the invention while the PCM is transitioning phase. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0026]    The following documentation provides a detailed description of the invention. 
         [0027]    Although a detailed description as provided in the attachments contains many specifics for the purposes of illustration, anyone of ordinary skill in the art will appreciate that many variations and alterations to the following details are within the scope of the invention. Accordingly, the following preferred embodiments of the invention are set forth without any loss of generality to, and without imposing limitations upon, the claimed invention. Thus the scope of the invention should be determined by the appended claims and their legal equivalents, and not merely by the preferred examples or embodiments given. 
         [0028]    As used herein, “phase change material” means a substance or mixture of substances with a heat of fusion which, when melting and solidifying at a phase transition, or phase change, temperature T enables the substance to absorb or release amounts of heat energy. Heat is absorbed or released when the substance changes state as from from solid to liquid, and vice versa, at the phase transition, or phase change, temperature T. T is a function of the physical properties of the phase change material. Phase change materials may comprise eutectic materials, salt hydrates, or organic materials. Eutectic materials tend to be solutions of salts in water that have a phase change temperature below 0° C. (32° F.). Salt hydrates are specific salts that are able to incorporate water of crystallization during their freezing process and tend to change phase above 0° C. (32° F.). Organic materials used as PCMs tend to be polymers with long chain molecules composed primarily of carbon and hydrogen. They tend to exhibit high orders of crystallinity when freezing and mostly change phase above 0° C. (32° F.). Examples of materials used as positive temperature organic PCMs include waxes, oils, fatty acids and polyglycols. The definition of “phase change material” or “PCM” further includes compositions comprised of more than one such substance, i.e., mixtures of phase change materials. Examples of substances which are phase change materials are shown in Table 1. 
         [0000]    
       
         
               
               
             
           
               
                   
                 TABLE 1 
               
               
                   
                   
               
             
             
               
                   
                 1-Cyclohexylooctadecane 
               
               
                   
                 2-Heptadecanone 
               
               
                   
                 3-Heptadecanone 
               
               
                   
                 4-Heptadacanone 
               
               
                   
                 9-Heptadecanone 
               
               
                   
                 Acetamide 
               
               
                   
                 Acetic acid 
               
               
                   
                 Acrylic acid 
               
               
                   
                 Actanilide 
               
               
                   
                 Alpha napthol 
               
               
                   
                 Aluminum 
               
               
                   
                 Azobenzene 
               
               
                   
                 Bee wax 
               
               
                   
                 Bees wax 
               
               
                   
                 Benzamide 
               
               
                   
                 Benzoic acid 
               
               
                   
                 Benzylamine 
               
               
                   
                 Bromcamphor 
               
               
                   
                 Camphene 
               
               
                   
                 Camphenilone 
               
               
                   
                 Capric acid 
               
               
                   
                 Caprilic acid 
               
               
                   
                 Caprylone 
               
               
                   
                 Catechol 
               
               
                   
                 Cetyl acid 
               
               
                   
                 Chloroacetic acid 
               
               
                   
                 Copper 
               
               
                   
                 Cyanamide 
               
               
                   
                 Dinto toluent (2,4) 
               
               
                   
                 Diphenyl amine 
               
               
                   
                 Docasyl bromide 
               
               
                   
                 Durene 
               
               
                   
                 Eladic acid 
               
               
                   
                 Formic acid 
               
               
                   
                 Glautaric acid 
               
               
                   
                 Glycerin 
               
               
                   
                 Glycolic acid 
               
               
                   
                 Glyolic acid 
               
               
                   
                 Gold 
               
               
                   
                 Heptadecanone 
               
               
                   
                 Heptaudecanoic acid 
               
               
                   
                 Hydrocinnamic acid 
               
               
                   
                 Hypophosphoric acid 
               
               
                   
                 Iron 
               
               
                   
                 KNO3 
               
               
                   
                 KNO3 (10%)/NaNO3 
               
               
                   
                 KNO3/KBr (4.7%)/KCl (7.3%) 
               
               
                   
                 KNO3/KCl (4.5%) 
               
               
                   
                 KOH 
               
               
                   
                 Lauric acid 
               
               
                   
                 Lead 
               
               
                   
                 Lithium 
               
               
                   
                 Methly brombenzoate 
               
               
                   
                 Methyl behenate 
               
               
                   
                 Methyl eicosanate 
               
               
                   
                 Methyl fumarate 
               
               
                   
                 Methyl palmitate 
               
               
                   
                 Mn(NO 3 ) 2 •6H 2 O + MnCl 2 •4H 2 O (4% w/w) 
               
               
                   
                 Myristic acid [35]   
               
               
                   
                 Na 2 SiO 3 •5H 2 O 
               
               
                   
                 NaCl (26.8%)/NaOH 
               
               
                   
                 NaCl (42.5%)/KCl (20.5)/MgCl2 
               
               
                   
                 NaCl (5.0%)/NaNO3 
               
               
                   
                 NaCl (5.7%)/NaNO3 (85.5%)/Na2SO4 
               
               
                   
                 NaCl/NaNO3 (5.0%) 
               
               
                   
                 NaCl/KCL (32.4%)/LiCl (32.8%) 
               
               
                   
                 NaCl•Na 2 SO 4 •10H 2 O 
               
               
                   
                 NaNO2 
               
               
                   
                 NaNO3 
               
               
                   
                 NaOH 
               
               
                   
                 NaOH/Na2CO3 (7.2%) 
               
               
                   
                 Nitro napthalene 
               
               
                   
                 O-Nitroaniline 
               
               
                   
                 O-Xylene dichloride 
               
               
                   
                 Oxolate 
               
               
                   
                 p-Bromophenol 
               
               
                   
                 p-Dichlorobenzene 
               
               
                   
                 p-Joluidine 
               
               
                   
                 p-Lattic acid 
               
               
                   
                 p-Xylene dichloride 
               
               
                   
                 Palmatic acid 
               
               
                   
                 Paraffin 14-Carbons 
               
               
                   
                 Paraffin 15-Carbons 
               
               
                   
                 Paraffin 16-Carbons 
               
               
                   
                 Paraffin 17-Carbons 
               
               
                   
                 Paraffin 18-Carbons 
               
               
                   
                 Paraffin 19-Carbons 
               
               
                   
                 Paraffin 20-Carbons 
               
               
                   
                 Paraffin 21-Carbons 
               
               
                   
                 Paraffin 22-Carbons 
               
               
                   
                 Paraffin 23-Carbons 
               
               
                   
                 Paraffin 24-Carbons 
               
               
                   
                 Paraffin 25-Carbons 
               
               
                   
                 Paraffin 26-Carbons 
               
               
                   
                 Paraffin 27-Carbons 
               
               
                   
                 Paraffin 28-Carbons 
               
               
                   
                 Paraffin 29-Carbons 
               
               
                   
                 Paraffin 30-Carbons 
               
               
                   
                 Paraffin 31-Carbons 
               
               
                   
                 Paraffin 32-Carbons 
               
               
                   
                 Paraffin 33-Carbons 
               
               
                   
                 Paraffin 34-Carbons 
               
               
                   
                 Pentadecanoic acid 
               
               
                   
                 Phenol 
               
               
                   
                 Phenylacetic acid 
               
               
                   
                 Polyethylene glycol 600 
               
               
                   
                 Quinone 
               
               
                   
                 Silver 
               
               
                   
                 Sodium sulfate (Na 2 SO 4 •10H 2 O) 
               
               
                   
                 Stearic acid 
               
               
                   
                 Stibene 
               
               
                   
                 Succinic anhydride 
               
               
                   
                 Thiosinamine 
               
               
                   
                 Thymol 
               
               
                   
                 Titanium 
               
               
                   
                 TME (63% w/w) + H 2 O (37% w/w) 
               
               
                   
                 Trimyristin 
               
               
                   
                 Tristearin 
               
               
                   
                 Water 
               
               
                   
                 Zinc 
               
               
                   
                 α-Chloroacetic acid 
               
               
                   
                 α-Nepthylamine 
               
               
                   
                 β-Chloroacetic acid 
               
               
                   
                   
               
             
          
         
       
     
       Examplary Phase Change Materials 
       [0029]    As used herein, “memory cell foam” means polyurethane with additional chemicals increasing its viscosity and density. It is often referred to as “viscoelastic” polyurethane foam, or low-resilience polyurethane foam (LRPu). Higher-density memory foam softens in reaction to body heat, allowing it to mold to a warm body in a few minutes. The invention may comprise any density memory foam, but may preferentially be comprised of memory foam that exhibits a density from less than 1.5 lb/ft 3  to 8 lb/ft 3  density. 
         [0030]    As used herein, “plastic” means a material consisting of any of a wide range of synthetic or semi-synthetic organics that are malleable and can be molded into solid objects of diverse shapes. Plastics are typically organic polymers of high molecular mass, but they often contain other substances. They are usually synthetic, most commonly derived from petrochemicals, but many are partially natural. Examples of plastics include but are not limited to polyester (PES); polyethylene terephthalate (PET); polyethylene (PE); high-density polyethylene (HDPE); polyvinyl chloride (PVC); polyvinylidene chloride (PVDC) (Saran); low-density polyethylene (LDPE); polypropylene (PP); polystyrene (PS); high impact polystyrene (HIPS); polyamides (PA) (Nylons); acrylonitrile butadiene styrene (ABS); polyethylene/Acrylonitrile Butadiene Styrene (PE/ABS); polycarbonate (PC); polycarbonate/Acrylonitrile Butadiene Styrene (PC/ABS); polyurethanes (PU); maleimide/Bismaleimide; melamine formaldehyde (MF); plastarch material; phenolics (PF) or (phenol formaldehydes); polyepoxide (Epoxy); polyetheretherketone (PEEK); polyetherimide (PEI) (Ultem); polyimide; polylactic acid (PLA); polymethyl methacrylate (PMMA) (Acrylic); polytetrafluoroethylene (PTFE); urea-formaldehyde (UF); furan; silicone; and polysulfone, or any combination of these materials. 
         [0031]    As used herein, “graphene” means an allotrope of carbon in the form of a two-dimensional, atomic-scale, hexagonal lattice in which one atom forms each vertex. A graphene covering or coating may comprise a plurality of single-atom layers. Graphene is the basic structural element of other allotropes of carbon, including graphite, charcoal, carbon nanotubes and fullerenes. It can also be considered as an indefinitely large aromatic molecule, the limiting case of the family of flat polycyclic aromatic hydrocarbons. Each graphene atom may have four bonds, one σ bond with each of its three neighbors and one π-bond that is oriented out of plane. The atoms are typically spaced about 1.42 Å apart. Graphene is often produced as a powder and as a dispersion in a polymer matrix. This dispersion is suitable for coatings and forming coverings. Graphene may be deposited using an ultrasonic spray, which may be an atomized spray, to create a homogeneous thin film layer of graphene. 
         [0032]    Referring now to  FIG. 1 , a cross section view of a phase change material temperature control pad  100  of an exemplary embodiment of the invention, depicting a phase change material  101  captured within a pliable enclosure forming an enclosed volume, and depicting an embodiment of a graphene covering overlying a portion of the pliable enclosure is depicted. Phase change material  101  is disposed in enclosure  102 , which may be a pliable enclosure. Graphene coating  103  is attached to and covers a portion of enclosure  102 . While a particular embodiment of graphene layer  103  is depicted in  FIG. 1 , graphene coating  103 , which may be ultrasonically deposited on an exterior surface of pliable enclosure  102 , may form a covering over any portion or all of enclosure  102 . Pliable enclosure  102  material may be any pliable material that will contain a PCM material, but is typically a plastic material. Pliable enclosure  102  may be fabricated by any means known in the art. In the case in which pliable enclosure  102  is fabricated from plastic material, seams may be formed by fabricating the enclosure from separate pieces or sheets of pliable plastic in which the seams are closed and sealed by any means known in the art such as chemical bonding, heat sealing, ultrasonic welding, or the like. 
         [0033]    Referring now to  FIG. 2A , a perspective view of the carrier and phase change material warming pad of an exemplary embodiment of the invention, showing the placement of the phase change material temperature control pad  100  into a carrier  120  of the invention is depicted. While a rectangular shape is depicted for both carrier  120  and the phase change material temperature control pad  100 , both carrier  120  and phase change material temperature control pad  100  may take any shape desired, and in the preferred embodiments of the invention, recess  121  is shaped to a complementary shape matching the exterior shape of phase change material temperature control pad  100  such that recess  121  is adapted to receive phase change material temperature control pad  100  with a close fit. For example, and not by way of limitation, phase change material temperature control pad  100  may take on a hexagonal, square, circular or other shape, and recess  121  may take on a complementary matching shape such that phase change material temperature control pad  100  is received by recess  121  with a close fit. 
         [0034]    Carrier  120  may be fabricated from any material, such as a compressible material, suitable for providing a compressible structure upon which a person may lie during surgery, such as, for example, open cell foam, closed cell foam or memory foam. In an alternative embodiment, carrier  120  may be fabricated from an expanded weave of plastic material comprised of plastic wire, which may be further defined as stiff plastic wire, and wherein the expanded weave of plastic wire acts as a compressible structure. Carrier  120  may be comprised of any compressible material, and may further comprise an outer covering fabricated from vinyl, fabric, rubberized fabric, or any other pliable mattress cover material known in the art. Preferably, the outer covering of carrier  120  comprises a waterproof, antimicrobial material. Upper surfaces C of carrier  120  may be, but are not necessarily, flush with upper surface B of phase change material temperature control pad  100  when phase change material warming pad  100  is placed within recess  121 . 
         [0035]    Referring now to  FIG. 2B , an end view of the carrier and phase change material warming pad of an exemplary embodiment of the invention, showing the placement of the phase change material temperature control pad  100  into carrier  120  is depicted. Carrier  120  may comprise a recess  121  adapted to receive phase change material warming pad  100  as depicted. Recess  121  may be bordered on three, or fewer or more, sides by a raised surface C which may be disposed above the bottom surface of recess by a dimension A. 
         [0036]    The phase change material temperature control pad  100  of the invention may have an upper surface B. Dimension A may be of such value that surface B is above, one the same plane as, or below surface C of carrier  120 . In an exemplary embodiment, surface C may be coplanar with phase change material temperature control pad upper surface B. 
         [0037]    Referring now to  FIG. 3 , an exemplary embodiment of the invention placed on a surgical table for warming a patient, further showing a patient disposed upon the phase change material temperature control pad of an embodiment of the invention is depicted. A patient may be placed upon a phase change material temperature control pad  100  of the invention that has been received by recess  121  in a carrier of the invention  120 . Typically, prior to use in a case where warming is desired, the temperature control pad  100  is “charged” to a temperature above a predetermined phase transition temperature. The predetermined phase transition temperature may be a temperature at which, given the temperature differential between the person&#39;s body and the PCM caused by the intervening material layers, which may comprise the temperature control pad  100  covering, graphene coating, and any other intervening materials, presents a desired temperature to the person&#39;s body while the PCM is transitioning states. For example, if it is desired to apply a temperature of  95 ° F. to a patient&#39;s body during the application of anesthesia during a medical procedure such as surgery, the thermal losses (and thus the temperature differential) between the patient&#39;s body and the PCM may be calculated using the known thermal properties of the intervening materials. In the example, assume a three degree (3°) F. drop in temperature. Thus it would be desired that the phase change material temperature control pad  100  of the invention transition phase at 98° F., and a suitable phase change material exhibiting this phase transition temperature T is selected. The temperature control pad  100  may then be charged to a temperature slightly above 98° F., causing the PCM material in phase change material temperature control pad  100  to liquefy. The phase change material temperature control pad  100  may then be placed into and received by recess  121  in carrier  120 , and the patient may be placed upon phase change material temperature control pad  100 . As the phase change material temperature control pad  100  cools to 98° F., it will begin to give off heat as the PCM transitions state from liquid to solid, and will continue to give off this heat for as long as the PCM continues to transition physical state. Thus, a constant temperature of 95° F., or any other temperature desired as determined by the selection of PCM or mixture of PCM comprising the invention, is applied to the patient&#39;s body for as long as the PCM continues to change state. 
         [0038]    Referring now to  FIG. 4 , an exemplary embodiment of the carrier  120  of the invention is depicted in which the carrier comprises an expanded weave  300  of plastic material comprised of plastic wire  301 , which may be further defined as stiff plastic wire, and wherein the expanded weave of plastic wire acts as a compressible structure. The expanded plastic weave which forms the carrier may be covered by a covering  302  such as vinyl or any other material which preferably, but not necessarily, does not absorb liquids. 
         [0039]    Referring now to  FIG. 5 , The present invention also comprises a method forming a series of steps for controlling the body temperature of a person, for example a person undergoing anesthesia during surgery, utilizing the phase change material temperature control pad  100  of the invention, comprising the following steps: 1) determining a desired temperature to apply to the body of a person in order to achieve a desired effect on the person  400 ; 2) selecting temperature control pad covering  102  material and thickness, and determining the temperature control pad covering material and graphene coating thermal resistance  401 ; 3) selecting PCM material for use in the temperature control pad for maintaining a constant pad temperature T while the PCM in the temperature control pad  100  is transitioning state, such that heat transferred to the body of a patient from the temperature control pad through the covering materials  102  and graphene coating, or heat transfer from the body of a patient to the temperature control pad through the covering materials  102  and graphene coating, results in a desired temperature being applied to the person&#39;s body given the thermal losses  402 ; 4) providing a temperature control pad comprising the selected PCM enclosed with the selected temperature control pad covering material and thickness  403 ; 5) charging the PCM material to a desired temperature that is above the PCM phase change temperature T in the case where it is desired to transfer heat to the body of a user from the temperature control pad, or charging the PCM material to a desired temperature that is below the PCM phase transition temperature T in the case where it is desired to transfer heat from the body of a user to the temperature control pad  404 ; and 6) causing the body of a person to be disposed upon the temperature control pad of the invention while the PCM material is undergoing phase transition  405 . 
         [0040]    In alternate embodiments of the method, more than one PCM may comprise the PCM utilized in the invention, resulting in the use of a PCM mixture, as may be necessary to achieve a specific desired PCM phase change temperature T, or to achieve any desired step function in, or duality of, PCM phase transition temperature T. In further alternate embodiments of the invention, one or more covering materials may be utilized, and each may be analyzed for thermal conductivity in order to achieve the desired thermal transfer between the body of a user and the temperature control pad.