Abstract:
An apparatus and method for warming and maintaining temperature of intravenous fluid, utilizing a heater contained in a cavity of the intravenous bag. The cavity can be configured by special manufacture or by modifying available intravenous bags. The modified intravenous bag may also have insulation material for retaining heat and thermal transfer material for efficiently transferring heat from the heating component to the intravenous fluid.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of Invention 
         [0002]    The present invention relates to medical devices in general and, in particular, to devices for warming intravenous (I.V.) bags and method of warming I.V. bags. 
         [0003]    2. Background 
         [0004]    In the use of medical equipment, intravenous fluids must be warmed up before administering to a patient. If the fluid is administered at a colder temperature to a patient, there is a serious risk of inducing hypothermia.
   In a hospital, there are numerous methods used for heating up an IV bag and maintaining the temperature. Microwave ovens are commonly utilized. Other methods include heating plates and convection ovens. These methods are satisfactory for a hospital. However, all of these methods are often large, heavy, and not portable.   
 
         [0006]    Military medics, paramedics, forest rangers, emergency response personnel and other people providing medical care outside of a hospital require a small, inexpensive, portable, lightweight device for heating and/or keeping intravenous fluids warm. If the fluid is not sufficiently warm when administered, the injured patient&#39;s survival chances decrease substantially before reaching the hospital. 
         [0007]    There are portable methods available for heating I.V. and blood fluids. These methods heat the fluids in tubes external to the bag. When a patient is in need of I.V. fluids, the medical professional must exert extra effort and time unpacking and setting up a tube-based heater. These devices tend to be heavy, expensive, and require precious setup time when time is of the essence in regards to the patient. One such commercial product can take several minutes to setup. Other products can take over ten minutes of time to warm the contents of the I.V. bag, requiring the medical provider to conduct a risk analysis of hypothermia versus delaying the administration of I.V. fluids. 
         [0008]    A field medic in the military, wilderness, or anywhere else away from the hospital has limited space to carry items and a maximum weight they can carry. Furthermore, when a patient is in immediate medical need, there is not ample time to connect extra components or heat a bag of I.V. fluid. For the forgoing reasons, there is a need for a smaller, less expensive, simpler, portable I.V. bag heater. 
       SUMMARY 
       [0009]    The present invention is directed to an apparatus and method of use that satisfies these needs. The apparatus comprises an I.V. bag containing fluid and configured in such a way as to create a cavity and a heater component that can be placed within the cavity. This apparatus is very light, takes up very little space, and is very inexpensive. In addition, the heater component can be activated far in advance of the anticipated need, whereas the I.V. fluid will maintain a safe warm temperature for an extended period of time, allowing the I.V. fluid to be ready for administration at any time without any advance notice. The cavity enclosing the heating component is enclosed by the I.V. fluid. The heating component, preferably comprising a heating element, such as a resistance wire, and a power source, such as a 9 volt disposable battery, can heat the I.V. bag all day, whereby, each day a new battery can be inserted into the power source and the I.V. bag is always ready to use. The I.V. fluid is enclosed in a second cavity. 
         [0010]    The I.V. bag can be specially manufactured in the shape of two elliptic parabaloids, or a standard I.V. bag can be modified. Utilizing a standard I.V. bag, a portion of the fluid is removed from a full bag and one end of the bag is inverted into the other end, thereby creating a cavity. A heating component is then inserted into this cavity. When activated, the heating component will heat the I.V. bag and I.V. fluid thereby creating a safe temperature for administration of the fluid into a patient. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    Many aspects of the invention can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the present invention. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views. 
           [0012]      FIG. 1  is a front view of the first embodiment of the present invention; 
           [0013]      FIG. 2  is a front view of the external apparatus of the present invention; 
           [0014]      FIG. 3  is a cutout view the thermal transfer material of the present invention; and 
           [0015]      FIG. 4  is a front view of the insulation casing and of the present invention. 
           [0016]      FIG. 5  is a perspective view of the heating component of the present invention. 
           [0017]      FIG. 6  is a front view of the present invention with fastening means. 
           [0018]      FIG. 7  is a front view of an I.V. bag with fluid hatch. 
           [0019]      FIG. 8  is a front view of an I.V. bag without fluid hatch. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0020]    In the Summary of the Invention above and in the Detailed Description of the Invention, and the claims, and in the accompanying drawings, reference is made to particular features (including method steps) of the invention. It is to be understood that the disclosure of the invention in this specification includes all possible combinations of such particular features. For example, where a particular feature is disclosed in the context of a particular aspect or embodiment of the invention, or a particular claim, that feature can also be used, to the extent possible, in combination with and/or in the context of other particular aspects and embodiments of the invention, and in the invention generally. 
         [0021]      FIG. 1  illustrates one preferred embodiment, an intravenous bag constructed of a flexible material having a top end  10  and a bottom end  12 , the bag comprising a first cavity  14  and a second cavity  16 , where the second cavity  16  is enclosed within the first cavity  14 , as illustrated in  FIG. 2 . The first cavity  14  is configured to store a fluid and the second cavity  16  is configured to hold a heating component  20 . Intravenous fluid  18  is hermetically contained between the first cavity  14  and the second cavity  16 . The I.V. bag may be manufactured having this configuration, or may use a commonly available I.V. bag and modifying it into this configuration. The second cavity  16  encloses the heating component  20 . By enclosing the entire heating component  20 , the heat is efficiently transferred to the intravenous fluid  18 , allowing for low power and quick heating and the ability to maintain a proper temperature for an extended period of time. The heating component  20  can be comprised of any electrical, chemical (exothermic reaction), or other kind of heating device. In this embodiment, the heating component  20  is comprised of a heating element  22 , preferably a resistance wire, and a power source  24 , such as an inexpensive disposable battery, a rechargeable battery, or a lithium ion battery. The preferred embodiment utilizes a disposable 9 volt battery because it is small, inexpensive, lightweight, and contains enough potential energy to power the heating element for at least one day. A medical professional can put in a battery before entering the field and the intravenous bag will stay at the proper temperature for several days or until needed. The power source  24  is preferably situated at the top  10  of the apparatus so that it can be removed, replaced, or recharged as needed. The apparatus is preferable for field medics because it adds no additional bulk and very little weight. When needing immediate warm intravenous fluid, the medical professional does not need to waste time setting up additional heating apparatus that is complicated, time-consuming, and prone to user error. The heating component may further comprise a temperature sensor and feedback device to operate at a consistent temperature. 
         [0022]      FIG. 3  shows a thermal transfer material  26  between the second cavity  16  and the heating component  20  (the power source element of the heating component is viewable in this figure). The surface of the thermal transfer material  26  is in contact with the second cavity  16  and the heating component  20 . The thermal transfer material  26  is composed of a material having attributes that increase thermal transfer efficiency between the heating component  20  and the intravenous fluid  18 . In another embodiment, the second cavity  16  is constructed from thermal transfer material  26  having hermetical attributes, thereby increasing thermal transfer efficiency even further. 
         [0023]    In another embodiment,  FIG. 4 , the intravenous bag is enclosed by a heat insulating casing  28 . This casing  28  may be constructed from Biaxially-oriented polyethylene terephthalate, or any other thermally insulating material. The casing  28  keeps the intravenous fluid  18  warm in order to increase efficiency. The casing  28  also decreases intravenous fluid  18  heat-loss if the heating component  20  fails or the power source  24  becomes depleted. The casing  28  may cover the top end  10 , bottom end  12 , and/or exterior sides (exterior sides covering shown in  FIG. 4 .) In another embodiment, the casing  28  can be attached the thermal transfer material  26  comprising one component, thereby also preventing the second cavity  16  from inverting. 
         [0024]      FIG. 5  illustrates the preferred embodiment of the heating component  20 , having a heating element  22 , in this case a resistance wire, and a power source  24 , show as an alkaline battery. The power source  24  is connected to and powers the heating element  22 . This particular embodiment is designed to function for at least one day and having a lightweight and inexpensive power source  24  that is replaceable quickly. 
         [0025]      FIG. 6  illustrates a means for fastening  30  the first cavity  14  to the second cavity  16 , thereby preventing the second cavity  16  from inverting. This particular means uses one or more connections to achieve the fastening means. Other fastening means can be clips, joints, seems, clasps, links, or other methods that would properly connect the first cavity  14  to the second cavity  16  to prevent the second cavity  16  from inverting. The fastening means  30  also adds stability to the invention, increasing overall durability. 
         [0026]    A method according to the present invention for heating an intravenous liquid, comprising the steps of providing a flexible material having a first cavity  14  and a second cavity  16 . The first cavity  14  and the second cavity  16 , each having the preferred shape of an elliptical paraboloid. The heating component  20  is then inserted into the second cavity  16  and turned on. The first cavity  14 , may enclose the second cavity  20  and may be filled with intravenous fluid  18 . The top end  10  of the first cavity  14  is connected and hermetically sealed with the top end  10  of the second cavity  16 . In the preferred embodiment, the heating component  20  comprising of the heating element  22  attached to the power source  24 . 
         [0027]    A method for heating an intravenous solution with a modified I.V. bag comprises the steps of providing an intravenous bag with fluid (shown in  FIG. 7  and  FIG. 8 ), removing a portion of the intravenous fluid  18 , inverting the top end  10  to create the second cavity  16 , and inserting a heating component  20  into the second cavity  16 . 
         [0028]    In the first step, a standard intravenous bag containing fluid available in most medical locations will suffice for the intravenous bag with fluid ( FIG. 7  &amp;  FIG. 8 ), preferably in the one liter size. Next, a portion of the intravenous fluid  18  is removed, thereby allowing enough space to invert the top end  10 , by pushing the top end  10  towards the bottom end  12 , creating a cavity  16 . The amount of fluid removed is approximately half the total fluid, but can be as little as approximately ¼ of the fluid or as great as approximately ¾ of the fluid. The amount of fluid removed would be determined by the actual size of the bag, the size of the heating component, the desired total size and total weight of the completed apparatus, and the anticipated need. The heating component  20  is inserted into, and completely enclosed by, the second cavity  16 . The heating component may be activated in anticipation of use to allow bag to reach desired temperature in advance of administration. For instance, a medic in the military would activate each power source before leaving base, thereby allowing the intravenous bag to remain at proper temperature for at least one day. 
         [0029]    Although the present invention has been described in considerable detail with reference to certain preferred versions thereof, other versions are possible. It is understood, therefore, that those and other modifications to the invention may be made, as might occur to one with skill in the field of this invention. Therefore, the spirit and scope of the appended claims should not be limited to the description of the preferred versions contained herein.