Abstract:
A heat pack for warming the heel of an infant with a front panel and a rear panel wherein the rear panel is adapted for placement on the infant&#39;s heel and has an outer layer formed of a nonwoven material which may be wetted. A band is provided for attaching the heat pack to the infant&#39;s heel. Heat from the heat pack effectively drives water applied to the nonwoven material into the infant&#39;s heel where it is then trapped in the skin under the heat pack. By thus moisturizing and softening the skin, a puncture necessary for taking a blood sample is eased.

Description:
[0001]    This application is a continuation-in-part of application Ser. No. 13/273,610, filed Oct. 14, 2011, which claims priority from provisional application Ser. No. 61/451,242, filed Mar. 10, 1011, for Infant Heel Heat Pack. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to an infant heel heat pack with a nonwoven backing that is soft and skin friendly for contacting a baby&#39;s foot. The nonwoven backing insulates the infant&#39;s skin from burning, promotes the nesting of the heat pack around the heel and can be wetted to soften the skin. 
         [0004]    2. Brief Description of the Prior Art 
         [0005]    Blood samples are drawn from the heel of infants. To promote blood circulation in the heel area, heat is applied with a heat pack. Such heat packs are commonly formed as a plastic pouch with a supercooled aqueous salt solution. A trigger is included in the pouch which when manually manipulated initiates crystallization of the supercooled liquid releasing heat. 
         [0006]    A front and back panel of a flexible polymer are sealed together about the side edges to form the plastic pouch which is preferably clear such that the trigger can be seen through the pouch. After crystallization has been triggered, the heat pack is taped on the infant&#39;s heel with the rear plastic panel pressed against the baby&#39;s skin. To soften the skin, nurses will wet the infant&#39;s heel with a wet cloth prior to inserting a needle. 
       BRIEF SUMMARY OF THE INVENTION 
       [0007]    It is an object of the present invention to provide a user friendly heat pack for an infant&#39;s heel that moisturizes the skin to facilitate the necessary puncture to obtain a blood sample. It is another object to provide a heat pack that cuts back on potential irritation and nests around the heel during heating trapping water applied by the heat pack in the skin. Other objects and features of the invention will be in part apparent and in part pointed out hereinafter. 
         [0008]    In accordance with the invention, a heat pack for warming the heel of an infant includes a plastic pouch with a front panel and a rear panel wherein the rear panel is adapted for placement on the heel of an infant and includes an outer layer formed of a nonwoven material capable of being wetted. Inside the pouch are a supercooled aqueous salt solution and a trigger capable of initiating crystallization. 
         [0009]    The heat pack may have a band for attachment of the heat pack to the heel of an infant with a message formed with a thermochromic material that signals when the heat pack is at a temperature suitable for application to the heel of an infant. The band may also have a non-slip coating. 
         [0010]    The invention summarized above comprises the constructions hereinafter described, the scope of the invention being indicated by the subjoined claims. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
         [0011]    In the accompanying drawings, in which one of various possible embodiments of the invention is illustrated, corresponding reference characters refer to corresponding parts throughout the several views of the drawings in which: 
           [0012]      FIG. 1  is a top plan view of a heat pack in accordance with the present invention; 
           [0013]      FIG. 2  is a side, sectional view, taken along the plane of  2 - 2  in  FIG. 1 ; 
           [0014]      FIG. 3  is an enlarged sectional view, not to scale, taken along the plane of  3 - 3  in  FIG. 2 ; 
           [0015]      FIG. 4  is a side view of the heat pack showing manipulation of a trigger for initiating crystallization; and, 
           [0016]      FIG. 5  is a front elevation of an infant&#39;s foot showing the heat pack fastened on the infant&#39;s heel. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0017]    Referring to the drawings more particularly by reference number, reference numeral  10  refers to an infant heel heat pack in accordance with the present invention. An ideal but non-limiting size for heat pack  10  fitted to a baby&#39;s foot is 3½ by 5 inches. Heat pack  10  is formed as a flexible pouch  14  with a front panel  16  and a rear panel  18 , the construction of which is discussed below. 
         [0018]    Pouch  14  provides a container for a supercooled aqueous salt solution which, when activated releases heat. Suitable solutions include supercooled sodium acetate, lead acetate, calcium nitrate tetrahydrate, sodium pyrophosphate and sodium thiosulfate solutions. Sodium acetate may be preferred because it is generally harmless to humans. 
         [0019]    The salt solution is made by dissolving the salt in a desired amount of water. The amount of salt to be utilized should permit the salt solution to be supercooled to at least the ambient temperature at which the heat pack is intended to be utilized. The supercooled aqueous salt solution may include a small amount of a viscosity increasing agent. A variety of gelling or thickening agents are commercially available, have been proposed for use in heat packs before and may be used. 
         [0020]    As seen in  FIGS. 1-2  and  4 , a trigger  20  to initiate crystallization is included in pouch  14 . Many triggers have been used in prior art heat packs and may be used in the present heat pack. For example, trigger  20  may be a metal disc or disc formed of flint, garnet, aluminum oxide, silicon carbide, alumina-zirconia, chromium oxide, ceramic aluminum oxide and so forth. What is important is that when trigger  20  is manually manipulated as shown in  FIG. 4  by pressing the disc between thumb and index finger of one or both hands, the disc initiates crystallization. 
         [0021]    Front panel  16  of pouch  14  can be made from a flexible plastic material. Suitable flexible materials include plastics used in the food industry such as polyolefins, copolymers of ethylene, substituted olefins, polyesters, polycarbonates, polyamides, acrylonitriles and so forth. A plastic laminate such as nylon polylaminate may also be used for front panel  16 ; suitable materials for such purpose having a thickness in the range of about 1 mil to 10 mils. 
         [0022]    Rear panel  18  is formed as a laminate, an essential feature of which is that an outer layer  22  be formed of a nonwoven material. An illustrative cross-section of a rear panel  18  is shown in  FIG. 3 . Non-limiting examples of nonwoven materials suitable for outer layer  22  include nylon, rayon, cellulose ester, polyvinyl derivatives, polyolefins, polyamides, polyesters, natural materials such as wool, silk, jute, hemp, cotton, linen, sisal, ramie and combination thereof. The nonwoven material may be formed by a suitable process such as, for example melt blowing, spunbonding, card webbing, etc. For example,  42  gsm White SMS polypropylene untreated, Product Code B0116, sold by PGI of Mooresville, N.C. has been used. The polypropylene is spunbond and combined with meltblown polypropylene to form a layered SMS (spun-melt-spun) product. The polypropylene SMS is water-repellent but capable of adsorbing water on the surface and applying a film of water to an infant&#39;s heel. Other of the nonwoven materials mentioned above may also be wetted prior to application of the heat pack to an infant&#39;s heel. 
         [0023]    An adhesive  24  attaches nonwoven outer layer  22  to an inner layer  26  which may be bonded to front panel  16 . Inner layer  26  may also be a composite as shown in  FIG. 3  wherein a first layer  28  is formed of a biaxial oriented polymer film. Biaxially oriented polyamides, polyethylene terephthalate or the like are generally much stronger in terms of tear strength and thus may be used to reinforce the nonwoven outer layer  22 . A second layer  30  is formed of a flexible plastic material that can be bonded to or fused with the plastic material making up front panel  16 . Front panel  16  and second layer  30  may be formed of the same material or not. 
         [0024]    A specific example of rear panel  18  comprises nonwoven outer layer  22 , adhesive  24 ,  60  gauge biaxially oriented nylon (BON) as first layer  28 , adhesive  24  and 3 mil clear low linear density polyethylene (LLDPE) as second layer  30 . The 60 gauge BON is manufactured by American Biaxis, Inc. Laminating adhesive  24  is sold under the trade name TYCEL and is manufactured by Henkel Adhesive. The LLDPE is manufactured by Appleton Performance Packaging-Films. 
         [0025]    A band  32  is attached to heat pack  10  for the purpose of attaching the heat pack to a heel  34  of an infant as shown in  FIG. 5 . For this purpose a patch  36  of adhesive is provided on opposite ends of band  32  for connecting to front panel  16 . Before heat pack  10  is applied to heel  34  and after crystallization has been initiated, a peel-off strip  38  over patch  36  as shown in  FIG. 2  may be removed exposing patch  36  for attachment of the free end of band  32  to front panel  16 . Band  32  may have a non-slip coating to keep heat pack  10  in place on an infant&#39;s heel. 
         [0026]    A message  40  such as “Safe” as shown in  FIG. 1 , “Safe to Use” or the like may be printed on band  32  in a thermochromic ink or dye to let the operator know that heat pack  10  is at a proper temperature to be placed on infant&#39;s heel  34 . For example, message  40  could appear when the temperature is somewhere between 98° and 105° Fahrenheit. Suitable thermochromic substances include liquid crystals and leucodyes. The indicator used for message  40  may include two or more different thermochromic materials that change color at different temperatures. For example, the indicator may include a first thermochromic material that is blue when heat pack  10  is below 98°, a second thermochromic material that turns green when heat pack  10  is within the desired temperature range, and a third thermochromic materials that turns orange when heat pack  10  is above 105°. Thermochromic materials can also be combined with non-thermochromic dyes and/or pigments to form message  40 . For example, message  40  formed with non-thermochromic indicia may be obscured by a thermochromic coating that becomes translucent at a predetermined temperature, e.g., when a temperature above 105° has been reached. 
         [0027]    In use, trigger  20  in heat pack  10  is flexed as shown in  FIG. 4  initiating crystallization. When heat pack  10  has reached the suitable operating temperature, message  40  on band  32  may appear signaling that heat pack  10  is safe to apply to heel  34  of the infant and nonwoven outer layer  22  is preferably wetted. Strip  38  is peeled off patch  36  and heat pack  10  is attached to heel  34  with band  32  as shown in  FIG. 5  with nonwoven outer layer  22  in contact with the baby&#39;s skin. As crystallization proceeds nonwoven layer outer layer  22  causes heat pack  10  to nest about the infant&#39;s heel thereby keeping it in place. Nonwoven outer layer  22  also insulates the infant&#39;s skin from burning and cuts back on potential irritation. The heat of the heat pack  10  drives water which has been applied to nonwoven outer layer  22  into the infant&#39;s skin where it is then trapped under the heat pack. The water moisturizes and softens the skin on the infant&#39;s heel thereby facilitating entry of a needle. 
         [0028]    In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained. As various changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.