Abstract:
An inexpensive and disposable cooling device for relieving pain associated with hypodermic injection that can be used with any hypodermic syringe includes a body and a sterile cooling medium within the body. A removable cover closes the body and maintains the sterility of the cooling medium before use. The device can be used to simultaneously cool a number of injection sites, eliminating the additional time required to serially cool the multiple injection sites.

Description:
FIELD OF THE INVENTION  
       [0001]     The invention relates to devices that relieve pain associated with hypodermic injection and methods for relieving pain associated with hypodermic injection.  
       DESCRIPTION OF THE PRIOR ART  
       [0002]     The pain associated with hypodermic needle injection is often a reason given for delaying or avoiding health care.  
         [0003]     It is known, however, that cooling the skin de-sensitizes the skin and enables hypodermic injection with little or no pain.  
         [0004]     Cooling devices have been developed that are used in combination with hypodermic syringes to cool the skin immediately prior to injection. Such devices tightly hold the syringe and include a syringe support that is pressed against the skin. The syringe support is pre-chilled to well-below room temperature and cools the skin upon contact. After sufficient time has passed to de-sensitize the skin (typically about 20 seconds), the injection is made.  
         [0005]     Although useful, conventional cooling devices have a number of disadvantages. The syringe support is adapted to receive hypodermic syringes of a specific size, and is made of metal for efficient heat transfer between the skin and the support. This makes conventional cooling devices relatively expensive to manufacture, increasing purchase cost. A number of different supports must be kept on hand for use with different-sized syringes, increasing inventory cost. The supports are not disposable and are re-used, increasing storage costs. And the supports must be sterilized by medical staff before use, increasing operating cost.  
         [0006]     Furthermore, conventional cooling devices are capable of only cooling the skin around a single injection site. Many procedures, however, require multiple injections. A separate cooling device for each injection must be provided, further increasing inventory cost. This also presents a problem not previously recognized, that serial cooling of multiple sites increases patient anxiety.  
         [0007]     To illustrate, a typical series of lumbar spine injections may require eight injections spread over an area measuring 20 cm by 15 cm. Each injection requires the use of a separate cooling device to cool an injection site, so eight devices must be provided. The injections must be spaced apart a minimum of 20 seconds to serially apply the cooling devices against the skin, adding at least 160 seconds to the procedure and forcing an already anxious patient to endure a substantially longer procedure.  
         [0008]     Therefore there is a need for an improved cooling device to reduce the pain associated with hypodermic injection, and an improved method for cooling multiple injection sites. The device should be inexpensive to manufacture and be disposable, be usable with any hypodermic syringe, and not require sterilization prior to use. The method should enable cooling the skin around multiple injection sites without materially increasing the time to carry out the injections.  
       SUMMARY OF THE INVENTION  
       [0009]     The present invention is an improved cooling device to reduce the pain associated with hypodermic injections. The device is inexpensive to manufacture and can be used with any hypodermic syringe. The device is also disposable and does not have to be sterilized by medical staff before use.  
         [0010]     Embodiments of the device can be used to simultaneously cool an additional number of injection sites. The additional time required to serially cool multiple injection sites is thereby eliminated.  
         [0011]     A cooling device in accordance with the present invention includes a body having an open end and an interior wall extending inwardly from the open end. The interior wall partially defines a reservoir that extends into the body. A cover removably seals and closes the open end of the body, the cover and interior wall enclosing the reservoir. A cooling medium is in the reservoir, the cooling medium being retained in the body when the cover is removed.  
         [0012]     The body, cover and cooling medium are capable of being cooled to an application temperature substantially below room temperature. Removing the cover exposes the cooled cooling medium such that placing the open end of the body against the skin causes sufficient heat transfer between the cooling medium and the skin to materially de-sensitize the skin.  
         [0013]     In preferred embodiments the body is molded as a single piece of plastic. This enables the device to be inexpensive and disposable. The cooling medium in possible embodiments is sterile water that becomes ice at the application temperature (0 degrees Centigrade or below). Sterile water or ice is inexpensive and readily available. Other cooling mediums or application temperatures can be used.  
         [0014]     Alternative embodiments of the device can be sized to cover and simultaneously cool a number of injection sites. The device can be configured to cool multiple sites extending substantially along a straight line or distributed within an area. The cooling medium is applied against an area of skin having a perimeter that encloses the injection sites. The cooling medium is capable of cooling the skin sufficiently to simultaneously de-sensitize each of the injection sites.  
         [0015]     The cooling medium is maintained against the area of skin for a length of time sufficient to materially de-sensitize the entire area of skin. The hypodermic injections are serially administered at the injection sites while the area of skin remains de-sensitized without additional application of a cooling medium between injections. Even if only some of the injection sites were simultaneously cooled, a substantial savings of time and patient pain and anxiety would be achieved.  
         [0016]     Other objects and features of the invention will become apparent as the description proceeds, especially when taken in conjunction with the accompanying  2  drawing sheets illustrating six embodiments of the invention. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0017]      FIG. 1  is an elevation view of a first embodiment cooling device in accordance with the present invention;  
         [0018]      FIG. 2  is a sectional view of the cooling device shown in  FIG. 1  taken along line  2 — 2  of  FIG. 1 ;  
         [0019]      FIG. 3  is an enlarged view of region A shown in  FIG. 2 ;  
         [0020]      FIG. 4  is a representational view of an injection site cooled by the cooling device shown in  FIG. 1 ;  
         [0021]      FIG. 5  is an elevation view of a second embodiment cooling device in accordance with the present invention;  
         [0022]      FIG. 6  is a representational view of multiple injection sites cooled by the cooling device shown in  FIG. 5 ;  
         [0023]      FIG. 7  is an end view of the applicator end of a third embodiment cooling device in accordance with the present invention;  
         [0024]      FIG. 8  is an end view of the applicator end of a fourth embodiment cooling device in accordance with the present invention;  
         [0025]      FIG. 9  is a sectional view similar to  FIG. 2  of a fifth embodiment cooling device in accordance with the present invention; and  
         [0026]      FIG. 10  is a view similar to  FIG. 3  of a sixth embodiment cooling device in accordance with the present invention. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0027]      FIGS. 1-3  illustrate a first embodiment cooling device  10  in accordance with the present invention. The device  10  is intended for cooling an area of skin around a single injection site.  
         [0028]     Device  10  includes a tubular body  12  holding cooling medium  14  within the body. A removable cover  16  sealingly closes the body  12  and prevents the release of cooling medium from the device prior to use.  
         [0029]     The body  12  is preferably molded or otherwise formed as a single piece of plastic or other insulating material, and extends between an open end  18  and a closed end  20 . An applicator portion  22  is formed on the open end of the body, with handle portion  24  extending from the applicator to the closed end. Inner body wall  26  extends inwardly from the open end of the body through the applicator portion  22  and partially defines a reservoir  28  that holds the cooling medium  14 . In the illustrated embodiment the reservoir also extends through the handle portion  24 . A circumferential lip  30  immediately adjacent the open end of the body extends into the reservoir  28  from the inner wall and retains the cooling medium  14  in the body after the cover  16  is removed.  
         [0030]     Cover  16  is formed from substantially planar sheet material, such as foil, that is attached to the open end of the body  12  by an adhesive joint  32 . The joint  32  seals the entire circumference between the body and the cover. The cover  16  and body interior wall  26  enclose the reservoir  28 .  
         [0031]     Cooling medium  14  is sterile water, and the body  12  is sterilized prior to being filled with the cooling medium  14 . The side of the cover  16  facing the cooling medium  14  is also sterilized so that the cover  16  protects the cooling medium from the ambient environment and maintains a sterile environment within the reservoir  28 .  
         [0032]     Prior to use the device  10  is placed in a freezer, standing on the cover  16 . The water freezes to ice, the ice formed with a flat lower surface against the cover  16 . The volume of the reservoir  28  is sufficient to accommodate expansion of the ice without deforming the cover  16  or the body  12 .  
         [0033]     It is anticipated that the device  10  will be provided in an entirely sterile condition as described, and come prepackaged as a ready-to-use item in a sterile package or “peel pack” containing a number of the devices  10 . The packaging would facilitate the placement of a device  10 , when frozen, directly onto a sterile surgical field.  
         [0034]     In use, the device  10  is removed from the freezer and grasped by the handle. The handle extends away from the ice  14  and enables grasping the device  10  without substantial heat transfer through the handle. Cover  16  is peeled away from the body  12 , exposing the ice  14 . The exposed ice  14  is sterile, having been protected by the cover, and no sterilization by medical staff is required.  
         [0035]     Lip  30  functions to retain the ice in the body after the cover  16  is removed and prevents the ice from falling out of the body. If the ice sufficiently adheres to the body wall  26 , the adhesion can function to retain the ice in the body and the lip  30  can be omitted.  
         [0036]     The applicator portion  22  is pressed against the skin at the injection site so that the sterile ice  14  cools the skin. As shown in  FIG. 4 , the free end of the applicator portion  22  is shaped to chill or cool a circular area  36  centered on an injection site  38 . The ice has the thermal capacity to de-sensitize the area  36 , and is typically pressed against the skin for about 20 seconds to achieve the desired therapeutic effect.  
         [0037]     The device  10  is then removed and a hypodermic injection is made in the conventional manner. The device  10  is disposed of after use.  
         [0038]     The device  10  is configured for cooling a single injection site. A number of devices  10  can be serially used to cool a number of spaced-apart injection sites.  
         [0039]      FIG. 5  illustrates a second embodiment cooling device  110  formed in accordance with the present invention. The device  110  is intended to simultaneously cool a number of injection sites. Device  110  is similar to device  10 , having a body  112  and a removable cover  114  enclosing cooling medium (not shown). The applicator end of the body is shaped for chilling an elongated area of skin  116  containing a number of injection sites  118   a ,  118   b  and  118   c  (see  FIG. 6 ). After the entire area  116  is sufficiently cooled, serial hypodermic injections are administered at the now de-sensitized injection sites. The skin remains de-sensitized without additional cooling between injections.  
         [0040]      FIGS. 7 and 8  illustrate additional applicator shapes that can be used in alternative embodiments of the present invention. The injector sites shown in the figures are intended to be representative of multiple injection sites and not limiting to the scope of the invention.  
         [0041]      FIG. 7  illustrates an oval-shaped applicator end  210  that can be sized to cool a single injection site or to simultaneously cool two or more injection sites such as sites  212   a ,  212   b , and  212   c . The oval shape is especially useful for single injection sites if infiltration of the medicant sub- and intradermally occurs that would otherwise also cause pain. For example, infiltration of local anesthetic used for carpal tunnel release typically measures about 10 cm by 5 cm. The larger applicator area cools and de-sensitizes infiltrated skin away from the injection site that would otherwise be unaffected using the applicator  10 .  
         [0042]      FIG. 8  illustrates a “C” shaped applicator end  310  (“C” shaped is intended to include “U” shapes, crescent shapes, horseshoe shapes, and other curved shapes). This shape is useful for areas, such as the breast, where injection sites extend along semi-lunar, semi-circular, or elliptical paths. For example, shape  310  may be designed to partially surround a nipple that is the typical 5 cm to 6 cm in diameter and cover injection sites  312   a ,  312   b , and  312   c.    
         [0043]      FIG. 9  illustrates a fifth embodiment cooling device  410  similar to the device  10  that omits the lip  30  and has an alternative means for retaining the ice when the cover is removed. The device  410  has a body  412  and a removable cover  414  like the cover  16 . The body  412  includes an applicator portion  416  similar to the applicator portion  22 , and a handle portion  418  that define the inner body wall  420  partially enclosing reservoir  422 . A retaining rod  424  extends from the wall  420  at the top of the reservoir and extends into cooling medium  426 . The water  426  freezes on the retaining rod  420  so that when the cover is removed the ice remains attached to the rod  420 . In other embodiments the lip and retaining rod can be used together.  
         [0044]      FIG. 10  illustrates a portion of a sixth embodiment cooling device  510  having a body  512  and removable outer cover  514  sealing the open end of the body and maintaining the sterility of a cooling medium  516 . A sterile inner cover  518  extends across the open end of the body and is permanently attached to the body by adhesive joint  520 . The outer surface of lip  522  (formed like lip  30 ), forms part of the joint  520  and provides additional adhesive area between the body and the inner cover.  
         [0045]     The device  510  is cooled below room temperature to the desired application temperature. The outer cover  516  is removed immediately prior to use and exposes the sterile inner cover  518 . In this embodiment the adhesive joint  520  functions to retain the cooling medium  516  in the body when the outer cover  514  is removed.  
         [0046]     The device  510  is pressed against the skin with the inner cover  518  engaging the skin. Heat transfer occurs through the inner cover  518 , and so the inner cover  518  itself forms part of the cooling medium. The inner cover  518  is sufficiently thin to not substantially impede heat transfer with the skin, or can be made from a heat-conductive material.  
         [0047]     The cooling medium  516  may include a water/glycol mixture or a water/alcohol mixture that remains liquid at application temperature. In other embodiments ice or some other freezable substance that is solid at application temperature can be in the device  10 , with the inner cover containing any melt liquid that might be generated.  
         [0048]     The illustrated embodiments use a cover formed from sheet material that adheres to the end of the device body or to an inner cover. In other possible embodiments the cover can be attached in other ways known in the art, including frictional engagement or with the use of threaded connections.  
         [0049]     Other cooling mediums that can be used with the present invention include gels, such as a single phase change material (PCM), used to regulate the temperature of products.  
         [0050]     While I have illustrated and described preferred embodiments of my invention, it is understood that this is capable of modification, and I therefore do not wish to be limited to the precise details set forth, but desire to avail myself of such changes and alterations as fall within the purview of the following claims.