Patent Application
20160051404
1. Technical Field
The present invention relates generally to an external therapeutic cooling device that contains a cooling medium. More specifically, the invention includes a flexible bag filled with a plurality of free-flowing particulates such that the cooled bag and contents can be shaped to the human anatomy for use in therapeutic cooling of injured joints.
2. Description of Related Art
Cold compresses are commonly used to provide cooling therapy to patients preparing for or recovering from trauma such as surgery or injury. Such cooling can reduce swelling in bodily tissues.
Ways to cool bodily tissue are known in the art. One such example is an ice pack. Ice is well suited as a cooling medium due to its large latent heat of fusion. Because ice has a large latent heat of fusion, it can absorb a relatively large amount of heat before it begins to melt. This property has led to the wide use of ice as a cooling means, especially therapeutic cooling. Some ice packs are thick and inflexible plastic containers filled with water that becomes ice upon freezing. Such packs, resembling a closed book, are flat and rigid. Another type of ice pack comprises a flexible rubber package with a screw on lid into which ice chunks can be placed. These ice packs, however, have great drawbacks. One drawback is that the ice pack is heavy. Another more serious drawback is that the ice pack presents a limited cooling surface area. This is especially true if the ice pack is being applied to a patient's face. The flat and rigid ice pack is incapable of conforming to the contours of a patient's face. The flexible rubber ice pack can better conform to contours than the flat ice pack, but the potential surface area is limited to the size of the ice chunks. Even if the ice is broken into smaller pieces, the resulting surface area is insufficient because as the ice melts, the water drains toward the low part of the pack forming a pool. When water drains into such pools, the cooling surface area is greatly reduced, and as a result the cooling efficiency is also reduced. Thus, the ice pack is unsuitable for some therapeutic purposes.
Prior art attempts to obviate the problem of limited surface area have instituted packs that exhibit flexibility. Some packs consist of water and an antifreeze agent. The antifreeze agent prohibits the pack from freezing and thus makes the pack flexible. However, because the water is not frozen, one drawback is that the unfrozen pack fails to take advantage of the large heat of fusion of the ice. Consequently, although the unfrozen pack is flexible, it fails to offer the same cooling potential as an ice pack. Other packs consist of a plurality of chambers, each chamber being filled with water. When the pack is frozen, the pack is bent and the ice is broken to provide limited flexibility. Although such a chambered pack takes advantage of the properties of ice, it also lacks the ability to contour a patient's face or other areas as it provides only limited surface area. Other packs consist of a polymer and water mixture that turns into a gel. One disadvantage in these packs is the propensity of water molecules to clump together and freeze. These clumps can be broken, but flexibility and surface area is still lost.
Despite all the options provided by the prior art, many medical professionals still use a frozen bag of peas as a therapeutic cooling medium. Because each pea acts independent of the other peas, when a bag of peas is placed on a patient's face the free-flowing peas are able to rise and fall to match the contours of the patient's face and/or other anatomical structures. This ability to mimic the contours of the patient's face maximizes surface contact and as a result provides efficient and effective cooling. Despite its wide use, there are several disadvantages of using peas. One such disadvantage is that organic matter decomposes and emits an odor because of bacterial contamination. Such decomposition and bacterial contamination can result in additional perceptive problems from transmission of odor through the bag material or as a result of leaking as bags of peas often have leaking seals. Such leaking can also result in medical problems as any bacteria can potentially undesirably leak onto the skin.
Another disadvantage is that medical professionals often place a bag or rag over the bag of peas for sanitary purposes. This reduces both the heat transfer and the contouring ability of a bag of peas. Additionally, over time a bag of peas becomes unusable. This results from many iterations of freezing and thawing of the vegetable which causes the peas to lose the ability to retain water. When a pea has lost the ability to retain water, it loses its integrity and becomes mushy. As a result, the bag of peas is essentially an ice pack, which exhibits many of the disadvantages of the ice pack discussed above. The water, not being absorbed by the pea, can form bridges or clumps of ice. This undesirably reduces surface contact. Thus, a need exists for a therapeutic cooling medium that mimics the high surface area and effectiveness of a bag of peas while further reducing disadvantages of the prior art. Further, a need exists for a therapeutic cooling medium that permits the addition of a bacteriostatic or bactericidal agent that inhibits or destroys the growth of bacteria.
An exemplary embodiment of a cold compress used for therapeutic cooling comprises a permanently sealed flexible elastic bag comprised of a water and water vapor impermeable film. The bag has an interior volume containing a plurality of free-flowing spheres, where each of the plurality of free-flowing spheres has a surrounding outer layer and contains a material. The material has a freezing point of about 0° C., and the material absorbs latent heat to convert from a frozen state to a liquid state. The interior volume of the sealed bag is free of any fluid that freezes at about 0° C. to about −25° C. Thus avoiding potential bridging between the spheres that hinders the free-flowing of the spheres. When cooled to a safe cold temperature for use as a cold compress, such as about 0° C., the cold sealed elastic bag remains flexible and elastic, and the plurality of spheres remain free-flowing such that the cooled sealed bag can be manually pressed to a simply curved surface or a compound curved surface of the human body to conform to the shape of the simply curved or compound curve. As a result, the bag has a heat transfer contact surface area with the simply curved or compound curved surface of the body to absorb heat through the heat transfer contact surface from the simply curved or compound curved surface of the body. The absorbed heat provides latent heat to frozen material inside the plurality of spheres. Accordingly, until phase change from frozen solid to liquid is complete, temperature of the cold compress does not change (increase) significantly, but remains substantially constant. Thus, the temperature of the cold sealed flexible elastic bag is substantially maintained until a substantial proportion of the frozen material has liquefied.
Optionally, the bag may be configured with an integral or separate strap for ease of attachment to or around a body part of the human anatomy in need of treatment.
Optionally, the material inside each of the plurality of spheres may be selected from those materials that melt (undergo a phase change) at a temperature that is not harmful to human tissue when the cold compress is used. Thus, a non-limiting list of such materials includes water (ice melts at 0° C.), certain waxes, and a variety of other compositions that either occur naturally, or can be formulated based on physical properties. For reasons of costs, non-toxicity, and safety, water is preferred, but the invention is not limited to water as the sphere-filler material. When water or another material that expands upon phase change is used, the surrounding outer layer or “shell” of each of the plurality of spheres must be sufficiently elastic or strong to not rupture upon expansion.
Optionally, the material in the spheres may include a bactericide.
Optionally, the spheres may be in the size range from about 3 to about 10 mm. Mixed sizes may be used in any cold compress embodiment.
In another exemplary embodiment, the permanently sealed flexible elastic bag contains a substance that is liquid, non-reactive with the plurality of spheres, non-reactive with the flexible elastic sealed bag, and is not a solid in the range from about 0° C. to about −25° C. Thus in normal use, when cooled in a domestic freezer or hospital freezer for use as a cold compress, the substance remains liquid, albeit that viscosity and other physical properties may change, and does not cause bridging between the plurality of spheres, or only cause very minimal bridging so that the capability of the cold compress to conform to complex human body surfaces is not impaired. Thus, for a cold compress, the substance should have a lower freezing point than the freezing point of the material inside the spheres. Optionally, the substance inside the permanently sealed elastic flexible bag may be a gel, or a saline solution, or a like natural or synthetic composition having these physical characteristics. A saline solution is preferred for low cost and lack of toxicity, but other compositions may be preferred for better performance.
Optionally, the spheres may be coated to provide a “slick” non-stick surface, or the outer layer (“shell”) of each sphere can be made of a non-stick material, such as the polytetrafluoroethylene type polymers, commonly referred to as PTFE, and known by the trademark TEFLON (a trademark of DuPont de Nemours), and the like.
Optionally, the sealed flexible elastic bag may be compartmentalized by internal dividers into multiple compartments, each containing a plurality of spheres. This may facilitate in the effective wrapping or placing the bag on a simply or compound curved body part, in some circumstances. Each of the dividers may be perforated to allow fluid communication between the compartments to facilitate effective wrapping or placing the bag on a simply or compound curved body part. Alternatively, the dividers may be impermeable permitting no inter-compartment fluid flow. Optionally, at least some of the plurality of spheres are tethered to an inner surface of the compartments of the permanently sealed flexible elastic bag. Optionally, weighting elements are contained in the compartments of the bag for “weighted feel” and for other purposes. Optionally, the plurality of spheres are distributed in a pattern by fixed attachment to a flexible structure that is sized and configured to fit inside the compartments of the flexible elastic bag. Optionally, the flexible structure is “net-like” with a predetermined pattern of attachment points for each sphere or weighting element.
Another exemplary embodiment provides a cold compress used for therapeutic cooling comprising a permanently sealed flexible elastic bag comprised of a water and water vapor impermeable film. The interior volume of the sealed flexible elastic bag contains a structure comprised of a flexible plate having arrayed therein a plurality of geometric shaped cavities. Each of the cavities has a volumetric capacity that contains sealed therein a material having a freezing point. Thus, when the cold compress is in use, the material absorbs latent heat to convert from a frozen state to a liquid state. Further, when the cold compress is in use, the cold sealed flexible elastic bag remains flexible and elastic, and the plate remains flexible so that the cold compress conforms to a simply curved or compound curved surface of the human body and thereby presents a heat transfer contact surface area with the simply curved or compound curved surface of the body to absorb heat through the heat transfer contact surface area from the simply curved or compound curved surface of the body.
Optionally, at least some of the cavities is filled with a weighting element, such as metallic beads or the like. Optionally, the bag is divided internally into multiple compartments by dividers, and at least some of the compartments contains the structure comprised of a flexible plate having arrayed therein a plurality of geometric shapes.
In an exemplary embodiment there is provided a reusable cold compress, as a cooling medium by providing a hygienic disposable sheath sized for the sealed flexible elastic cold compress bag to slide into.
The above as well as additional features and advantages of the present invention will become more apparent in the following detailed description.
The novel features and characteristic of embodiments of the inventions are set forth in the appended claims. However, objectives and advantages may be better appreciated by reference to the following detailed description of illustrative exemplary and non-limiting embodiments, when read in conjunction with the accompanying drawings, wherein:
Like reference numerals represent equivalent parts throughout the several drawings:
Referring now to the provided drawings, similar reference numerals represent the equivalent component throughout the several views of the drawings.
Referring to
In an exemplary embodiment, the cold compress 100 may comprise two sheets of overlapping film that are sealed along each of four peripheral edges. The permanently sealed bag 102 useful in the present application is not limited by the number of seals, or by the method of manufacture. In an embodiment, the cold compress 100 can be transparent and seen to enclose the free flowing spheres 200.
In an exemplary embodiment, the cold compress 100 is configured and sized to wrap around a simple or compound curvature of a human body part and being held in place by attaching to itself, or another object, by VELCRO, mechanical clips, tape, or any other suitable means. In an exemplary embodiment, the cold compress 100 includes an affixing strap (not shown) that can be used to fasten the cold compress 100 to an anatomical structure. The affixing strap can wrap around a body member and affix to itself or to a portion of the cold compress 100. The size and shape of the cold compress 100 can be varied depending on the application. For example, if the cold compress 100 is to be applied to a patient's face, the bag 102 can have a slightly rectangular shape and be about the size of a sheet of paper (about 22 cm by 28 cm). Likewise, if an ankle is to be treated then the cold compress 100 could be more elongate for ease of wrapping around the entire ankle yet wide enough to cover only the ankle.
The bag 102 can comprise any flexible material that conducts heat and preferably has barrier properties as to water (liquid) and water vapor. Elasticity of the bag material is also desirable for ease of stretching around compound curvatures, and to allow the bag to return to its original “as manufactured” shape. A bag that has heat insulating properties (very low thermal conductivity) would decrease the effectiveness of the invention since body heat has to pass through the bag to the cooling medium inside the bag.
The bag 102 is preferably made of a material that has barrier properties to water and water vapor. Barrier properties are preferred because if moisture was allowed to enter the bag, the formation of ice bridges between particulates, such as spheres, within the bag causes hard clumps that can inhibit flexibility and contouring ability of the bag to conform to simple or compound anatomical curves. This decreases the contact surface area between the cold compress bag and the body part being cooled. Undesirable moisture in the bag can bond to or coat the spheres and, when frozen, form hardened inflexible frozen clumps of spheres. Consequently, in an exemplary embodiment, the bag 102 comprises water and water vapor properties sufficient to avoid clumping of the cooling medium, such as spheres, within the bag. As used herein, sufficient bag water barrier properties is defined as a bag having a water vapor transmission rate of less than about 20 g/mill/645.16 sq. cm (100 sq. in.)/day at 37.8° C. (100° F.) and 90% relative humidity with a preferable rate of less than about 2 g/mill/645.16 sq. cm (100 sq. in.)/day at 37.8° C. (100° F.) and 90% relative humidity.
The bag material must also be flexible at temperatures lower than the freezing temperature of water (0° C.) as well as temperatures greater than about 38° C. (body temperature). The bag should not become rigid and inflexible at lower temperatures at which the cold compress will be used as this will decrease the effectiveness of the cold compress. Likewise, the bag cannot melt or stretch inelastically at temperatures around body temperature (−38° C.). In one embodiment of the invention, the bag 102 is made from flexible films known in the art. The flexible film may be selected from polymers and polymer composites, such as but not limited to: high density polyethylene, medium density polyethylene, low-density polyethylene, polycarbonate, polypropylene, linear low density polyethylene, polyethylene terephthalate, polyvinyl chloride, polystyrene, polyurethane, polycarbonate or other suitable material, having the properties described herein.
In an exemplary embodiment, the bag 102 is made from other suitable materials or material composites, including, but not limited to, cloth-like materials such as micro-fibers, nylon, cotton, GORE-TEX, polyester blends, interwoven textiles and water-resistant paper such as waxy paper.
Referring to
The particulate outer layer, such as the sphere outer layer 206 can be made of any material that has sufficient water and water vapor barrier and heat transfer properties. The sphere outer layer 206 should conduct heat, and should be water tight. The sphere outer layer 206 should act as a sufficient barrier to water vapor. As used herein, sufficient sphere barrier properties is defined as a sphere outer layer 206 having a water vapor transmission rate of less than about 20 g/mill/645.16 sq. cm (100 sq. in.)/day at 37.8° C. (100° F.) and 90% relative humidity with a preferable rate of less than about 2 g/mill/645.16 sq. cm (100 sq. in.)/day at 37.8° C. (100° F.) and 90% relative humidity. In an exemplary embodiment, the sphere outer layer 206 has a low coefficient of expansion. The reason for this is that if the outer layer 206 shrinks or expands with temperature at a much different rate than the fluid 208 it contains, then the sphere could crack or split. In alternative embodiments, the material of the sphere outer layer (“shell”) is elastic and expands and contracts as its contents freeze or liquefy.
In another exemplary embodiment, the sphere outer layer 206 comprises a non-stick material. As used herein, a non-stick material is one that does not bond or stick to itself so that the spheres remain free-flowing. If the sphere outer layer 206 was made of such a material (e.g., a gel) then the spheres would tend to cluster, reducing surface area and heat transfer. In one embodiment of the current invention, the outer sphere layer 206 is selected from one or more polymer or composites selected from, low, medium, or high density polyethylene, polypropylene, linear low density polyethylene, polyethylene terephthalate, polyvinyl chloride, polystyrene, polyurethane, or other suitable material. Other suitable non-stick, water tight materials can include, but are not limited to, metals, or metal composites, such as aluminum or steel, or a silica-based material such as fiberglass. In another embodiment the outer sphere layer 206 comprises glass, titanium, or brass.
Alternatively, in one embodiment, the outer sphere layer 206 is coated with a non-stick material such as a fluoropolymer such as polytetrafluoroethylene (PTFE) or a silicone-based coating comprising silicone resins, elastomers, oils or silicone glazes to help ensure the spheres are free-flowing.
In one embodiment, the sphere 200 is partially filled with a fluid 208 that is liquid at ambient conditions. Because of convenience and the high latent heat of fusion of H2O, in one embodiment of the invention the fluid 208 comprises water. The water can be then be frozen into ice. Using ice permits the user of the instant invention to absorb a large amount of heat at substantially constant cold compress temperature before the ice begins to melt to water, and the cold compress temperature begins to increase gradually. Additionally, because of the availability of freezers to users of the cold compress, the temperature required to make ice, 0° C., is very achievable and convenient.
The conduction of heat is expressed by the mathematical formula below:
Q=cmΔT
Where Q=Heat Conducted or Heat Transferred
A material's heat capacity, denoted as “c” in the equation above, is quantified by the amount of heat energy required to raise the temperature of the material by a certain amount, such as 1° C.
In an exemplary embodiment, a fluid having a relatively high heat capacity is used. Thus, the fluid does not freeze at the temperature of use of the cold compress, but remains a fluid inside the spheres or other shaped particulates, and absorbs heat without phase change. The fluid 208 should have a high specific heat, greater than about 1 J/gram/Kelvin at 25° C. (constant pressure), and preferably greater than about 4 J/gram/Kelvin at 25° C. (constant pressure) in the liquid phase. Water in the liquid form exhibits a higher specific heat or heat capacity than water in the solid form (ice). For example, the heat capacity of water is 4.187 kJ/kg K and the heat capacity of ice is 2.108 kJ/kg K. Accordingly, faster heat transfer may be possible if liquid water is utilized.
One advantage of embodiments of the present invention is that, because the fluid 208 is placed into water-tight spheres, the fluid 208 can comprise coolants such as gels that would otherwise be undesirable because of the tendency of such gels to stick to one another. Thus, a fluid can be selected to maximize the amount of cooling time provided by the cold compress 100 of the present invention.
The driving force, denoted as “ΔT” in the equation above, is the temperature difference between the temperature of a patient's body part and the temperature of the bag material in communication with the body part. The driving force can be increased by supplying a colder medium in communication with the body part. One simple way to accomplish this is to add salt or an antifreeze solution to the water solution, thus lowering the freezing point. Depending on the concentration of the salt-water mixture, temperatures as low as −21° C. (for NaCl) can be reached without the mixture freezing. Further, because the spheres are water tight, and are further in a sealed flexible bag, any fluid used is less likely to leak and come into contact with a user than many prior art embodiments. Consequently, heat transfer fluids that may otherwise not be advisable for use can be used in accordance with various embodiments of the present invention.
As further clarification, one objective of one embodiment of the present invention is to provide a cold compress that can transfer at least as much heat (Q) from an anatomical member as a similar sized bag of frozen peas. As shown by the above formula, this can be achieved by using heat transfer fluids with high “c” values and/or by increasing the driving force (ΔT). Consequently, in one embodiment, the driving force is maximized by using a heat transfer fluid that does not freeze in a standard freezer, e.g., at temperatures lower than −22° C. Thus, in one embodiment, the heat transfer fluid comprises an antifreeze solution. This can permit a larger driving force to be utilized.
Alternatively, in an exemplary embodiment, it may be desirable to take advantage of the latent heat of fusion provided by a frozen fluid and a larger driving force than would be provided by water alone. Thus, in an exemplary embodiment, the heat transfer fluid comprises a chemical mixture to decrease the freezing point of the heat transfer fluid, but that permits the heat transfer fluid to freeze in a standard freezer, e.g., at temperatures higher than −22° C. The chemical mixture can be a salt (MgCl, NaCl, etc) added to water or any other suitable mixture that results in a freezing point of higher than −22° C.
In an exemplary embodiment, the volume of fluid 208 to be filled in each sphere 200 may depend on the expansion coefficient of the fluid 208 and the outer sphere layer material 206. Determination of the amount of fluid 208 to fill a given sphere size is within the knowledge of one skilled in the art. In this embodiment the sphere 200 is only partially filled with liquid 208 at room temperature. When partially filled, the sphere 200 has sufficient void space 209 within it to allow for liquid expansion at reduced temperatures. This will prevent the sphere from cracking or splitting due to the expansion pressure of the fluid 208. For example, it is known that water expands in volume by about 10% when frozen. As a result, in this embodiment the sphere 200 has a void space that occupies about 10% or more of the volume of the water. Depending on the expansion coefficient of the fluid 208 and the material used in manufacturing the sphere outer layer 206 the void space 209 can occupy up to about 50% of the total sphere volume, with a preferred void space volume of less than about 25% and most preferably between about 5% and about 15% of the total sphere volume as calculated by the sphere inner diameter 204. This allows the water to expand when frozen, and not split or crack the outer sphere layer 206. In another exemplary embodiment, the sphere 200 is completely filled with fluid. In such an embodiment, the sphere outer layer 206 is made of a flexible material that can expand (i.e. it is elastic) with the fluid 208. This flexible elastic material allows the fluid to expand without causing the sphere to crack or split. In one embodiment, the sphere thickness 210 is adjusted according to the level of fluid placed into the sphere 200.
In an exemplary embodiment, the spheres 200 may be manufactured on a machine called a “Blow-fill-seal Machine.” Such machines are known in the art and commonly used for the aseptic packaging of pharmaceuticals. The spheres can be made as follows: First, the outer sphere layer 206 is formed by extruding the material around a mold and blowing air into the mold to form the bulk of the sphere 200. Next, a measured dose of fluid 208 is injected into the partial sphere 200. Finally, the sphere 200 is capped or sealed on top.
Other suitable machines or methods can be used to manufacture the spheres 200. For example, U.S. Pat. Nos. 5,254,379 and 6,532,947 disclose methods of filling a substantially spherical object with a fluid. While these patents are directed towards paintballs, those skilled in the art will understand that such methods can be adapted to make the spheres of the present invention. Other suitable machines or methods such as vacuum form molding can also be used.
While one embodiment describing spheres 200 filled with a fluid has been disclosed, in another embodiment a solid object can be utilized. For example, the sphere 200 can comprise glass beads. These solid beads operate as previously described. For example, these solid beads are frozen or cooled to lower temperatures. When applied, heat is transferred from the object to be cooled to the solid beads. Other beads such as titanium beads, brass beads, copper beads, and other such beads which offer desirable heat transfer properties can also be suitably used. These include, but are not limited to, other metals and ceramics which have a high specific heat such as aluminum.
Referring to
In an exemplary embodiment, to minimize heat absorption from the environment, and to promote heat absorption from the body part to which it is applied, the cold compress is provided with a heat insulating side facing the environment, and a heat conduction side interfacing with the body part. Thus, the cold compress would be useful (i.e. “cold”) for a longer time before it needs to be cooled again in a freezer. Heat insulation can be achieved by selection of bag sidewall material and thickness, and by adding a highly reflective coating or film of a metal, such as aluminum. Such a coating or film will also readily indicate to the user which side should face the surrounding environment in use, and which should be placed on the body part.
In an exemplary embodiment, the cold compress 100 is placed into a sheath that is sized such that the cold compress 100 can be placed inside the sheath.
Use of the sheath facilitates reusability of the cold compress by the user and/or health care providers. For example, in one embodiment, before the cold compress 100 of the present invention is used on a patient, a sheath 400 is applied to the outer portion of the bag 102. When the cold compress 100 is subsequently removed, the sheath can be removed and discarded and the cold compress 100 can be optionally washed and/or disinfected and placed into a freezer for re-use. The sheath can also be made from many of the same materials disclosed above to make the bag 102.
In one embodiment, the sheath comprises a device for attaching the bag 102 to an anatomical structure. The same devices discussed above, such as VELCRO, mechanical clips, tape, or any other suitable device so long as the cold compress 100 helps to fasten the bag 102 to an anatomical structure.
In an exemplary embodiment illustrated in
An exemplary embodiment of a cold compress used for therapeutic cooling comprises a permanently sealed flexible elastic bag comprised of a water and water vapor impermeable film. The bag has an interior volume containing a plurality of free-flowing spheres, where each of the plurality of free-flowing spheres has a surrounding outer layer and contains a material. The material has a freezing point of about 0° C., and the material absorbs latent heat to convert from a frozen state to a liquid state. The interior volume of the sealed bag is free of any fluid that freezes at about 0° C. to about −25° C. Thus avoiding potential bridging between the spheres that hinders the free-flowing of the spheres. When cooled to a safe cold temperature for use as a cold compress, such as about 0° C., the cold sealed elastic bag remains flexible and elastic, and the plurality of spheres remain free-flowing such that the cooled sealed bag can be manually pressed to a simply curved surface or a compound curved surface of the human body to conform to the shape of the simply curved or compound curve. As a result, the bag has a heat transfer contact surface area with the simply curved or compound curved surface of the body to absorb heat through the heat transfer contact surface from the simply curved or compound curved surface of the body. The absorbed heat provides latent heat to frozen material inside the plurality of spheres. Accordingly, until phase change from frozen solid to liquid is complete, temperature of the cold compress does not change (increase) significantly, but remains substantially constant. Thus, the temperature of the cold sealed flexible elastic bag is substantially maintained until a substantial proportion of the frozen material has liquefied.
Optionally, the bag may be configured with an integral or separate strap for ease of attachment to or around a body part of the human anatomy in need of treatment.
Optionally, the material inside each of the plurality of spheres may be selected from those materials that melt (undergo a phase change) at a temperature that is not harmful to human tissue when the cold compress is used. (Applying a very cold compress for a long time may cause “cold burn” and tissue damage. In general, the colder the compress the shorter the time for cold burn. Accordingly, a cold compress should have a temperature tolerable for human tissue when applied for the time periods specified). Thus, a non-limiting list of such materials includes water (ice melts at 0° C.), certain waxes, and a variety of other compositions that either occur naturally, or can be formulated based on physical properties. For reasons of costs, non-toxicity, and safety, water is preferred, but the invention is not limited to water as the sphere-filler material. When water or another material that expands upon phase change is used, the surrounding outer layer or “shell” of each of the plurality of spheres must be sufficiently elastic to not rupture upon expansion.
Optionally, the material in the spheres may include a bactericide.
Optionally, the spheres may be in the size range from about 3 to about 25 mm. Mixed sizes may be used in any cold compress embodiment. In addition, to add a “dead weight feel” to the cold compress, weighting elements in any of a variety of shapes, but most commonly spheres, that may be solid metallic, may be added to the bag contents to increase mass and develop that feel. The added mass may also facilitate conformance of the compress to body curvatures.
In another exemplary embodiment, the permanently sealed flexible elastic bag contains a substance that is liquid, non-reactive with the plurality of spheres, non-reactive with the flexible elastic sealed bag, and is not a solid in the range from about 0° C. to about −25° C. Thus in normal use, when cooled in a domestic freezer or hospital freezer for use as a cold compress, the substance remains liquid, albeit that viscosity and other physical properties may change, and does not cause bridging between the plurality of spheres, or only cause very minimal bridging so that the capability of the cold compress to conform to complex human body surfaces is not impaired. Thus, for a cold compress, the substance should have a lower freezing point than the freezing point of the material inside the spheres. Optionally, the substance inside the permanently sealed elastic flexible bag may be a gel, or a saline solution, or a like natural or synthetic composition having these physical characteristics. A saline solution is preferred for low cost and lack of toxicity, but other compositions may be preferred for better performance. The substance may serve one or all of several functions, such as transferring heat absorbed through the bag film to the spheres, permit more even cooling of the skin, and adding mass to the cold compress to aid in conformance to curved body parts.
Optionally, the spheres may be coated to provide a “slick” non-stick surface, or the outer layer (“shell”) of each sphere can be made of a non-stick material, such as the polytetrafluoroethylene type polymers, commonly referred to as PTFE, and known by the trademark TEFLON (a trademark of DuPont de Nemours), and the like.
Optionally, the sealed flexible elastic bag may be compartmentalized by internal dividers into multiple compartments, each containing a plurality of spheres. This may facilitate in the effective wrapping or placing the bag on a simply or compound curved body part, in some circumstances. Each of the dividers may be perforated to allow fluid communication between the compartments to facilitate effective wrapping or placing the bag on a simply or compound curved body part. Alternatively, the dividers may be impermeable permitting no inter-compartment fluid flow.
An issue that may arise in cold compresses whether the bag is fluid filled or not, is the tendency of spheres or other particulates to migrate under gravity (or other forces such as buoyancy) to cluster in parts of the cold compress thereby impairing heat absorption performance.
In order to address the migration issue,
As an alternative,
While the invention has been described with respect to exemplary embodiments, other variants may be apparent to a person of ordinary skill in the art who has read this disclosure of technology. These variants are deemed within the scope of the appended patent claims and their equivalents.
This application is a continuation-in-part of co-pending U.S. patent application Ser. No. 13/252,529 filed on Oct. 4, 2011, which is in turn a continuation-in-part of U.S. Ser. No. 11/539,020 filed on Oct. 5, 2006.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 13252529 | Oct 2011 | US |
| Child | 14928354 | US | |
| Parent | 11539020 | Oct 2006 | US |
| Child | 13252529 | US |
