Abstract:
A dressing for application over a blistered area on a surface of the skin of a patient. The dressing including: a volume forming portion positioned over the blistered area; an adhesive portion positioned proximate to the volume forming portion for fixing the volume forming portion to the skin; and a potential energy storage mechanism for storing potential energy that would tend to increase a volume adjacent to the blistered area formed by the volume forming portion to create a vacuum adjacent the blistered area.

Description:
BACKGROUND 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates generally to dressings, and more specifically to shape and pressure adjustable dressings. 
         [0003]    2. Prior Art 
         [0004]    In many situations, dressings are desired to apply certain amount of pressure on the wound or apply certain amount of force to close a wound or keep it closed, sometimes over time as inflammation subsides. In other situations, it may be desired to increase the pressure or force over time to assist healing without a change in the dressing. In yet other situations it may be desirable to vary the pressure or force distribution over time. However, the currently available materials used for dressing wound are difficult if not impossible to be used to achieve the above results in general, and to achieve it with ease and in a reliable manner in particular, even with the use of such aids as elastic components or tension fixtures. 
         [0005]    In other situations, the dressing may be required to cover certain surfaces over the body that due to the shape of the surfaces, it may be difficult to make a close fit and even more difficult to apply pressure to the surface and sustain the applied pressure over time. In such situations, the dressing has to not only conform to the covered surfaces, but at the same time may have to provide a certain pattern of pressure or force to achieve certain goals. 
         [0006]    In the U.S. Pat. No. 7,834,232 the inventors disclose methods and means of providing dressings that can be used to apply pressure to the skin for different types of wounds to perform many of the aforementioned tasks by releasing a member from the dressing to allow the dressing to change the shape of the dressing. In situations in which a blister has formed at a location on the patient skin such as due to burn of mechanical friction or impact, etc., and in particular when the fluid collected inside the blister under the skin of the injured region is applying relatively large enough pressure to the underlying tissues that reduces and in some cases even stops blood flow to these tissues, it is highly desirable to reduce such relatively high pressures to the underlying tissues to enhance blood flow into and out of these tissues to prevent further damage to these tissues and enhance the healing process. In certain situations, the above goal is achieved by providing certain amount of relative vacuum to over the blister region. In many situations, however, it is highly desirable to relieve the pressure by puncturing the blister to allow the fluid to be discharged—at least partially—to reduce the build-up of pressure. In general, it is also highly desirable that in addition to puncturing the blister to allow the fluid discharge, certain amount of vacuum to be also applied to the region to reduce the required size of the puncture; to assist fluid discharge; and to enhance fluid flow into and out of the underlying regions of the blister. Once the blister is punctured, it is essential that the punctured blister be kept clean and medicated to prevent the possibility of infection. 
       SUMMARY 
       [0007]    A need therefore exist for a method to construct dressings that can be readily applied to the blister area, and then have the capability of its shape to be varied to apply a relative vacuum (suction) to the blister area but expanding the sealed volume of the space over the covered blister area. The vacuum can be generated without any external vacuum sources. 
         [0008]    A need also exists for a method to construct the aforementioned sealed relative vacuum (suction) forming dressing such that they could be provided with the means of puncturing the surface of the blister to allow the collected fluid to be released into the vacuum induced volume over the blister. 
         [0009]    The aforementioned sealed relative vacuum (suction) forming dressings can also be capable of providing more than one said releasing members so that by their sequential release, the dressing shape is further changed to increase (or decrease) the said vacuum forming volumes and when desired their shape. 
         [0010]    The aforementioned sealed relative vacuum (suction) forming dressing volume can also be provided with means to absorb the released fluid from under the blister. 
         [0011]    The aforementioned sealed relative vacuum (suction) forming dressing volume can also be medicated to minimize the chances of infection to spread in the blister region enclosed by the dressing. 
         [0012]    In addition, the aforementioned sealed relative vacuum (suction) forming dressing could be provided with an access through which an external vacuum source could be attached to increase the level of vacuum within the enclosed volume over the blister area and when applicable to allow the fluid to be extracted from the said enclosed volume or fluids to be added, such a medicaments or therapeutic agents. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]    These and other features, aspects, and advantages of the apparatus and methods of the present invention will become better understood with regard to the following description, appended claims, and accompanying drawings where: 
           [0014]      FIG. 1(   a ) illustrates the schematic of the top view of a first embodiment of a blister dressing having a sealed volume forming layer and at least one sealed volume increasing layer. 
           [0015]      FIG. 1(   b ) illustrates the schematic of a cross-sectional view of the first embodiment of a blister dressing of  FIG. 1(   a ) with a sealed volume forming layer and at least one sealed volume increasing layer intact. 
           [0016]      FIG. 1(   c ) illustrates the schematic of the schematic of the cross-sectional view of  FIG. 1(   b ) of the first embodiment shown in  FIG. 1(   a ) with the first sealed volume increasing layer removed and the resulting change in the shape of the sealed volume forming layer to yield larger sealed volume over the enclosed blister area. 
           [0017]      FIG. 1(   d ) illustrates the schematic of the cross-sectional view of  FIG. 1(   b ) of the first embodiment shown in  FIG. 1(   a ) with a second sealed volume releasing layer removed and the resulting change in the shape of the sealed volume forming layer to yield even larger sealed volume over the enclosed blister area. 
           [0018]      FIG. 2  illustrates the schematic of the cross-sectional view of the first embodiment of a blister dressing of  FIG. 1(   a ) shown in  FIG. 1(   b ) with an added fluid absorbent layer below the sealed volume forming layer and at least one sealed volume increasing layer intact. 
           [0019]      FIG. 3(   a ) illustrates the schematic of the top view of another embodiment of a blister dressing having a sealed volume forming layer and at least one sealed volume increasing layer. 
           [0020]      FIG. 3(   b ) illustrates the schematic of the top view of the embodiment of  FIG. 3(   a ) following removal of a first sealed volume increasing layer. 
           [0021]      FIG. 3(   c ) illustrates the schematic of the top view of the embodiment of  FIG. 3(   a ) following removal of a second sealed volume increasing layer. 
           [0022]      FIG. 3(   d ) illustrates the schematic of a cross-sectional view of the embodiment of  FIG. 3(   a ) following removal of a first sealed volume increasing layer and forming of a space above the blister area with relative vacuum. 
           [0023]      FIG. 3(   e ) illustrates the schematic of a cross-sectional view of the embodiment of  FIG. 3(   a ) following removal of a second sealed volume increasing layer to further increase the volume of the space formed above the blister area and the generated relative vacuum. 
           [0024]      FIG. 4(   a ) illustrates the schematic of a cross-sectional view of the another embodiment of a blister dressing of  FIG. 3(   a ) with a sealed volume forming layer constructed in a “bellow-like” configuration that has been released to form a volume with relative negative pressure over a blister. 
           [0025]      FIG. 4(   b ) illustrates the schematic of a cross-sectional view of the embodiment of the blister dressing of  FIG. 4(   a ) before the “bellow-like” sealed volume forming layer has been released by at least one sealed volume increasing layer. 
           [0026]      FIG. 5(   a ) illustrates the schematic of a cross-sectional view of the another embodiment of a blister dressing of  FIG. 3(   a ) with a sealed volume forming layer constructed in a “circularly corrugated” configuration that has been released to form a volume with relative negative pressure over a blister. 
           [0027]      FIG. 5(   b ) illustrates the schematic of a cross-sectional view of the embodiment of the blister dressing of  FIG. 5(   a ) before the “bellow-like” sealed volume forming layer has been released by at least one sealed volume increasing layer. 
           [0028]      FIG. 6(   a ) illustrates the schematic of a cross-sectional view of an embodiment of a blister dressing with a sealed volume forming layer that is designed to deploy by a “deployable mechanism” once at least one sealed volume increasing layer is removed. 
           [0029]      FIG. 6(   b ) illustrates the schematic of a cross-sectional view of an embodiment of the blister dressing of  FIG. 6(   a ) after the sealed volume increasing layer has been removed and a sealed volume has been formed over the blister area. 
           [0030]      FIG. 7(   a ) illustrates a sectional view of another embodiment of blister dressing in an applied position. 
           [0031]      FIG. 7(   b ) illustrates a sectional view of the blister dressing of  FIG. 7(   a ) in a deployed (volume forming) position. 
           [0032]      FIG. 8(   a ) illustrates a sectional view of another embodiment of blister dressing in an applied position. 
           [0033]      FIG. 8(   b ) illustrates a sectional view of the blister dressing of  FIG. 8(   a ) in a deployed (volume forming) position. 
       
    
    
     DETAILED DESCRIPTION 
       [0034]    A schematic of a basic design of a blister dressing is shown in the  FIGS. 1(   a ) to  1 ( d ). In  FIG. 1(   a ), a top view of the blister dressing embodiment  10  is shown. It is noted that the circular shape of the sealed volume forming section  11  and the adhesive band section  12  are shown to be circular for presentation only and may take any other appropriate shape. The blister dressing  10  consists of a sealed volume forming section  11 , which is surrounded by an adhesive “band”  12 . The cross-sectional view A-A of the blister dressing  10  is shown in  FIG. 1(   b ). The sealed volume forming section  11  is shown to consist of a sealed volume forming layer  13  and two layers of sealed volume increasing layer  14  and  15 . The two layers are attached together and to the sealed volume forming layer  13  using any method known in the art, such as with adhesives, so that the user could readily separate them. The adhesive band  12  is permanently attached to the periphery of the sealed volume forming layer  13  using any method known in the art and may have a slight overlap to provide enough strength so that as the sealed volume forming layer deforms to generate a sealed volume, the integrity of the blister dressing  10  is ensured. When being used on a patient, the volume forming layer  13  is placed over the blister area  17 , and the adhesive band  12  of the blister dressing  10  is attached to the surface of the skin  16  firmly to seal the space between the volume forming layer  13  and the blister area of the skin that it covers. 
         [0035]    In the schematics of  FIGS. 1(   a )- 1 ( d ), for the sake of simplicity, only two distinct sealed volume increasing layers  14  and  15  are used. However, one or more than two such layers with different preloading patterns can be utilized in the construction of the present blister dressings. In addition, the blister dressing assembly  10  does not have to be initially flat, and may assume any appropriate shape and configuration as dictated with the particular application. 
         [0036]    Once the blister dressing  10  is applied to the skin  16  over the blister  17  and the adhesive band  12  is attached over the skin to seal the space between the blister  17  and the covering surface of the sealed volume forming layer  13 , the first sealed volume increasing layer  15  may be removed to increase the said sealed space between the blister  17  and the covering surface of the sealed volume forming layer  13 . Once the first sealed volume increasing layer  15  is removed, the mechanical potential energy stored in the sealed volume forming layer  13  is partially released as described later in this disclosure, allowing the sealed volume forming layer  13  to take the shape (dome-shaped)  18  as shown in  FIG. 1(   c ), thereby causing the space between the blister  17  and the covering surface of the sealed volume forming layer  18  (13 in its pre-release configuration) to be increased to form the space  19 . The resulting increase in the volume of the space between the blister  17  and the covering surface of the sealed volume forming layer  18  to form the space  19  will also generate a relative vacuum within the sealed space  19 . It is appreciated by those familiar with the art that as the sealed volume forming layer  13  is deformed following removal of the first sealed volume increasing layer  15 , the second sealed volume increasing layer  14  may slightly deform as shown in  FIG. 1(   c ) and form a bulge  20 . 
         [0037]    When a higher level of relative volume is desired to be generated within the space  19  over the area of the blister  17 , the second sealed volume increasing layer  14  may be removed to further increase the sealed space  19  between the covered area of the blister  17  and the covering surface of the sealed volume forming layer  21  (indicated by numeral  18  in  FIGS. 1(   c ) and  13  in  FIG. 1(   b )) as shown in  FIG. 1(   d ). Once the second sealed volume increasing layer  14  is removed, the mechanical potential energy still stored in the sealed volume forming layer  18  ( FIG. 1(   c )) is further released as described later in this disclosure, allowing the sealed volume  17  to further increase as shown in  FIG. 1(   d ), thereby causing the level of relative volume to further increase in the sealed volume  17 . 
         [0038]    In one embodiment, on at least a portion of the surface area under the volume forming layer  13 , such as extending over and certain amount past blister area  17  as shown in  FIG. 1(   b ), is provided with a layer of fluid absorbent material  22  to absorb the discharged fluid that is collected in the blister once it is released. The absorbent material  22  can also be medicated to prevent the chances of infection in the blister area, particularly following the rupture of the blister skin and discharging of the collected fluid. 
         [0039]    As discussed below, the material of the volume forming layer  13  can be such that it has the shape as indicated in  FIG. 1(   d ) but is restrained into a different shape, such as a flat shape as shown in  FIG. 1(   a ) by the volume increasing layers  14 ,  15 . As the volume increasing layers are removed, the restraint is also removed, allowing the volume forming layer  13  to take a different shape. Such materials can be fabrics, plastics or metals and can be formed integrally or separately from the adhesive band  12 . When formed separately, the volume forming layer  13  and adhesive band  12  can be attached by any means known in the art, such as heat welding, adhesive and the like. 
         [0040]    In another embodiment, at least one sharp puncturing tip  23  is provided over the surface under the volume forming layer  13  as shown in  FIG. 2 , such as extending at least partially through the fluid absorbent material layer  22  (when the dressing  10  is provided with a fluid absorbent layer  22 ). The user would then attach the blister dressing  10  over the blister area  17  such that the puncturing tip(s)  23  is over the surface of the blister. Then when desired, by pressing over the surface of the sealed volume increasing layer  15 ,  FIG. 2 , the surface skin of the blister  17  is punctured, allowing the collected blister fluid to begin to be discharged. It is appreciated that the aforementioned puncturing of the blister skin may be performed following removal of the first sealed volume increasing layer  15  or after the second sealed volume increasing layer  14  has also been removed. 
         [0041]    In the embodiments of  FIGS. 1-2 , particularly when the blister dressing is provided with blister puncturing tip(s)  23 ,  FIG. 2 , the material used to construct the volume forming layer  13  can be transparent, e.g., fabricated with a transparent medical grade plastic material. This is also the case for the first and second sealed volume increasing layers  15  and  14  and the adhesive band  12 . As a result, the user can more accurately position the volume forming layer  13  and its puncturing tip(s)  23  over the surface of the blister  17 . The fluid absorbent material layer  22  may also be provided with holes to allow the user to more accurately locate the dressing over the blister. 
         [0042]    It will be appreciated by those skilled in the art that the area around the puncturing tip(s)  23  of the fluid absorbent material layer  22  may be provided with local anesthetic medication so that the blister puncturing action becomes painless to the patient. 
         [0043]    The sealed volume forming layer  13  can be originally shaped essentially as shown in  FIG. 1(   d ) and indicated by numeral  21 , but has been elastically “flattened” (or brought to any other desired shape) and held in the flattened configuration (thereby resulting in a stored mechanical potential energy in the sealed volume forming layer  13 , which when released would tend to bring the sealed volume forming layer  13  to its aforementioned original shape) by the sealed volume increasing layers  14  and  15 . Obviously, if the sealed volume increasing layers  14  and  15  are separated from the blister dressing assembly  10 , as shown in  FIG. 1(   d ), sealed volume forming layer  13  would return to their original shape shown in  FIG. 1(   d ) and indicated by numeral  21 . 
         [0044]    It will be appreciated by those skilled in the art that the sealed volume forming layer  13  can be designed in numerous ways, a few of which are described later in this disclosure, such that the aforementioned mechanical potential energy that is stored in the sealed volume forming layer  13  when it is flattened to the configuration shown in  FIG. 1(   b ) is due to for example tensile or compressive or torsion or flexural bending or their combination induced potential energy. 
         [0045]    As an example, consider the blister dressing embodiment  10  of  FIG. 1(   a ), which is redrawn in  FIG. 3(   a ) and indicated by numeral  30 , with the sealed volume forming section  11  (in  FIG. 3(   a ) indicated by numeral  31 ) and the adhesive band section  32 . The sealed volume forming section  31  consists of at least one sealed volume increasing layer in general, and in the case of the blister dressing embodiment  30  shown in  FIG. 3(   a ), a first (top) sealed volume increasing layer  34  and a second sealed volume increasing layer  33 . Under the sealed volume increasing layers  33  and  34 , a sealed volume forming layer  35  (shown in  FIGS. 3(   b ) and  3 ( c ) but not visible in the top view of  FIG. 3(   a )) is provided which is attached to the adhesive band section  32  as previously was described for the embodiments of  FIGS. 1(   a )- 1 ( d ). In  FIG. 3(   a )- 3 ( c ) the sealed volume increasing layers  34  is considered to be positioned inside a provided (circular) opening  36  inside the sealed volume increasing layer  33 , but can overlap the sealed volume increasing layer  33  to ease its removal by the user. The sealed volume increasing layer  33  is considered to be positioned over the (circular) sealed volume forming layer  35  as shown in  FIG. 3(   c ), but is preferably overlapping the adhesive band section  32  to ease its removal by the user. 
         [0046]    In use, the blister dressing is attached over the blister  37  to the surface of the skin  38  as was described before for  FIG. 1(   b ) and shown in  FIG. 3(   d ). The first (top) sealed volume increasing layer  34  ( FIG. 3(   a )) is then removed ( FIG. 3(   b )), causing the underlying portion of the sealed volume forming layer  35  to form a volume  36  above the blister  37  as shown by the surface  39  in the cross-sectional view of  FIG. 3(   d ). The formation of the sealed volume  36  would generate a relative vacuum in the sealed volume  36 . When it is desired to further increase the relative vacuum (volume  36 ), the second sealed volume increasing layer  33  is removed, causing the size volume  36  to increase as shown by the surface  40 , thereby increasing the level of vacuum inside the volume  36  as shown in  FIG. 3(   e ). 
         [0047]    In another embodiment  50 , which is otherwise similar to the embodiments  30  of  FIGS. 3(   a ), the sealed volume increasing layer ( 13  in  FIGS. 1(   b ) and  2 ,  18  in  FIG. 1(   c ),  21  in  FIGS. 1(   d ), and  35  in  FIG. 3(   b )), is constructed in a “bellows-like” structure  45  shown in FIG.  4 ( a ), which is essentially “flattened” into the configuration  46  shown in  FIG. 4(   b ) and held in this configuration by a sealed volume increasing layer  47 , with a stored mechanical potential energy that when released would return to the configuration  45  (i.e., its original shape), thereby forming the volume  48  over the blister  37  area and generate a relative vacuum inside the volume  48  over the blister  37 . 
         [0048]    It will be appreciated by those skilled in the art that even though in the embodiment  50  of  FIGS. 4(   a ) and  4 ( b ) only one sealed volume increasing layer  47  was shown to be used, one may use more than one such sealed volume increasing layer as previously described for previous embodiments and use them similarly to sequentially increase the volume  48  over the blister  37  area and thereby increase the level of relative vacuum within the volume  48  and allow more fluid to be absorbed by the provided absorbent material (not shown in the schematics of  FIGS. 4(   a ) and  4 ( b )). 
         [0049]    In another embodiment  55  shown schematically in  FIGS. 5(   a ) and  5 ( b ), which is otherwise similar to the embodiments  30  and  50  of  FIGS. 3(   a ) and  FIG. 4(   a ), respectively, the sealed volume increasing layer is constructed in a “circularly corrugated” structure  51  shown in  FIG. 5(   b ). In the blister dressing  55  and prior to its application to a blister area, the sealed volume increasing layer is essentially “flattened” into the configuration  51  shown in  FIG. 5(   b ) and held in this configuration by a sealed volume increasing layer  52 , with a stored mechanical potential energy that when released would return to its configuration  53  (i.e., its original shape) shown in  FIG. 5(   a ), thereby forming the volume  54  over the blister  37  area and generate a relative vacuum inside the volume  54  over the blister  37 . 
         [0050]    It will be appreciated by those skilled in the art that even though in the embodiment  55  of  FIGS. 5(   a ) and  5 ( b ) only one sealed volume increasing layer  52  was shown to be used, one may use more than one such sealed volume increasing layers as previously described for previous embodiments of the present invention and use them similarly to sequentially increase the volume  54  over the blister  37  area and thereby increase the level of relative vacuum within the volume  54  and allow more fluid to be absorbed by the provided absorbent material (not shown in the schematics of  FIGS. 5(   a ) and  5 ( b )). 
         [0051]    It will also be appreciated by those skilled in the art that the mechanical potential energy may, at least partially, be stored in an element other than the pre-release (flattened) sealed volume forming layer ( 13  in  FIGS. 1(   b ) and  2 ,  35  in  FIGS. 3(   b ) and  3 ( c ),  46  in  FIGS. 4(   b ) and  51  in  FIG. 5(   b ), and the like). The stored mechanical potential energy can then be released by the aforementioned sealed volume increasing layer such the layers  14  and  15  of the embodiment of  FIG. 1(   b ), to deform the sealed volume forming layer into the desired shape, such as the one shown in  FIGS. 2(   c ) and ( 2   d ) for the embodiment of  FIG. 1(   b ). Such mechanical potential energy storing elements can take unlimited number of configurations and can be constructed using numerous materials with mechanical potential energy stored in them as strain energy or pressurized gas or the like and even as chemical energy, e.g., used to generate gasses in an enclosed volume. A few representative examples of such embodiments are presented below. However, it is noted that any other mechanical “deployable” mechanism known in the art with stored mechanical potential energy (in the form of strain energy or energy stored in the form of compressed gasses or gasses generated by a chemical reaction) may also be used. Hereinafter, the aforementioned mechanisms that provide at least part of the mechanical potential energy to cause the sealed volume forming layer to form an enclosed sealed volume (space) over the blister area is referred to as the “deploying mechanism”. 
         [0052]    The blister dressing embodiment  60  illustrated in the schematic of  FIG. 6(   a ) is an example of a blister dressing that is provided with an aforementioned “deployable mechanism”  62 . As can be seen in the schematic of  FIG. 6(   a ), the embodiment  60  is similar to the previous embodiments except for its sealed volume forming layer  61  and the deploying mechanism  62  that is used to force the sealed volume forming layer  61  to deform to the shape  66  and provide a sealed volume  63  shown in  FIG. 6(   b ) once the sealed volume increasing layer  64  ( FIG. 6(   a )) is removed. The deploying mechanism  62  shown in  FIG. 6(   a ) consists of at least one flexural (bending) spring (preferably substantially flat) that are positioned substantially in the radial direction with one end fixed to the adhesive band section  65 , preferably via a relatively rigid peripheral—circular in this case—element (not shown) to allow the aforementioned flexural spring elements to function as cantilever beams. In the configuration shown in  FIG. 6(   a ), the aforementioned flexural beams of the deploying mechanism  62  are elastically “flattened” and are held in the flattened by the sealed volume increasing layer  64 , thereby storing mechanical potential energy in the deploying mechanism for sealed volume  63  deployment. Once the sealed volume increasing layer  64  shown in  FIG. 6(   a ) is removed, the flexural beams of the deploying mechanism  62  (two of which are seen in the schematic of the cross-sectional view of  FIG. 6(   b ) and indicated by numerals  67 ) tend to return to their non-deformed configuration as shown in  FIG. 6(   b ) by their stored mechanical potential energy, and thereby deform the sealed volume forming layer  61  shown in  FIG. 6(   a ) to the shape  66  shown in  FIG. 6(   b ). 
         [0053]    In blister dressing embodiments using at least partially the aforementioned (sealed volume forming layer) deploying mechanisms, in its non-deployed configuration the sealed volume forming layer may be constructed by stretchable sheet of material such as latex, rubber or other available medical grade elastomeric material, and is then stretched by the elements (flexural elements in the case of the embodiment of  FIGS. 6(   a ) and  6 ( b )) to form a sealed volume over the blister area. Alternatively, in its non-deployed configuration the sealed volume forming layer may be constructed by a flexible sheet that is folded to be packed into its non-deployed state, and is then deployed (unfolded) by the elements (flexural elements in the case of the embodiment of  FIGS. 6(   a ) and  6 ( b )) to form a sealed volume over the blister area. In the latter case, the flexible sheet forming the sealed volume forming layer is preferably also at least partly stretchable to better deformable to the desired final shape. 
         [0054]    It is appreciated by those skilled in the art that the aforementioned deploying mechanisms may also be used to assist the deployment of the previously described embodiments. 
         [0055]    It will also be appreciated by those skilled in the art that the aforementioned deployable mechanisms can be constructed with the means of essentially locking their deploying elements (elements  62  and  67  for the embodiment  60  shown in  FIGS. 6(   a ) and  6 ( b )) in their deployed configuration (configuration  67  for the embodiment  60  shown in  FIGS. 6(   a ) and  6 ( b )). As a result, the volume formed by the sealed volume forming layer (volume  63  for the embodiment  60  shown in  FIG. 6(   b )) would resist certain amount of external pressure that might be accidentally be applied to the formed volume over the blister area. 
         [0056]    An example of such deploying mechanisms with the aforementioned locking capability is illustrated in the embodiment  70  with the cross-sectional view of it shown in the schematics of  FIGS. 7(   a ) and  7 ( b ). The embodiment  70  is similar to that of the embodiment  60  but is provided with a deployment mechanism that essentially locks after deployment to resist pressure applied to the deployed (formed) sealed volume over the blister area as described below. The embodiment  70  is still applied to the surface of the skin  38  over the blister  37  area by the sealing adhesive band  65 . The deploying mechanism consists of at least one pair of flexural (bending) spring (preferably substantially flat) elements  71  and  72 ,  FIG. 7(   a ), which are positioned substantially in the radial direction with one end fixed to the adhesive band section  65 , preferably via a relatively rigid peripheral—circular in this case—element (not shown) to allow the aforementioned flexural spring elements to function as cantilever beams. A “U” shaped end  75  is provided on the free end of the element  72 . In the configuration shown in  FIG. 7(   a ), the aforementioned at least one pair of flexural beams  71  and  72  of the deploying mechanism are elastically “flattened” and are held in the flattened by the sealed volume increasing layer  74 , thereby storing mechanical potential energy in the deploying mechanism elements  71  and  72  for sealed volume  76  deployment,  FIG. 7(   b ). Once the sealed volume increasing layer  74  shown in  FIG. 7(   a ) is removed, the mechanical potential energy stored in the elements  71  and  72  of the deploying mechanism will tend to return them at least partially to their non-deformed configuration as shown in  FIG. 7(   b ), seen in the schematic of the cross-sectional view of  FIG. 7(   b ) as indicated by numerals  77  and  78 , respectively, and thereby deform the sealed volume forming layer  73 ,  FIG. 7(   a ), to the shape  79  shown in  FIG. 7(   b ). The sealed volume forming layer  79  would thereby form a volume  76  with relative vacuum over the blister  37  area. 
         [0057]    In another embodiment, the pre-release (flattened) sealed volume forming layer ( 13  in  FIGS. 1(   b ) and  2 ,  35  in  FIGS. 3(   b ) and  3 ( c ),  46  in  FIGS. 4(   b ) and  51  in  FIG. 5(   b ), and the like) is at least partially (but preferably fully) retained by at least one “ retaining element” that resists (and can prevent) the pre-release (flattened) sealed volume forming layer to return to its original shape (configuration). The user may then release the pre-release (flattened) sealed volume forming layer by removing the aforementioned “retaining elements”. The retaining element may itself be held secured to the blister dressing (e.g., to the volume forming layer portion and/or the adhesive band) by an element similar to the aforementioned sealed volume increasing layers of the previous embodiments. Such “retaining elements” for partially or fully retaining the pre-release (flattened) sealed volume forming layer may be designed and constructed using many different methods known in the art and in many different ways, examples of which are provided below for illustrative purposes only and without limiting the present disclosure to their use. 
         [0058]    In one such embodiment  80 , shown in  FIG. 8(   a ), the sealed volume forming layer  81  is held in its pre-release (flattened) configuration and with stored mechanical potential energy by a partial or full ring type retaining element  82 . The blister dressing is otherwise similar to the embodiments of  FIGS. 1-5 , and is similarly applied to the surface of the skin  38  over the blister  37  area by the sealing adhesive band  65 . When the retaining element  82  is a full (circular or non-circular) ring, the ring material need only to provide tensile strength and does not have to provide any rigidity, and may for example be a thread with enough tensile strength. The retaining ring mating surfaces  83  on the sealed volume forming layer  81  may be provided with the lips  84  to prevent the retaining element  82  from slipping out. The lips  84  or the like to prevent unwanted release of the sealed volume forming layer  81  are required if no additional means (such as the aforementioned sealed volume increasing layers) are provided. Minimal or no such lips  84  are required when additional means such as at least one aforementioned sealed volume increasing layer  85  is provided to prevent unwanted release of the sealed volume forming layer  81 . When the retaining element  82  is an open “ring”, then the ring has to be rigid and strong enough to withstand the forces applied to the ring by the ring mating surfaces  83 . Once the blister dressing  80  is applied to the skin  38  over the blister  37  area, the user would remove/disengage/cut (depending on which one of the aforementioned alternative designs are used in the construction of the blister dressing) the retaining element  82 , thereby allowing the sealed volume forming layer to be deployed and deform to the shape  86  shown in  FIG. 8(   b ) and form a volume  87  with relative vacuum over the blister  37  area. 
         [0059]    The use of retaining elements such as the element  82  shown in the schematic of  FIG. 8(   a ) has the advantage of subjecting the sealed volume increasing layer to minimal (or no) force (when appropriately sized lips  84  are used), thereby making it easier for the sealed volume increasing layer to prevent untimely release (deployment) of the sealed volume forming layer. 
         [0060]    It will be appreciated by those skilled in the art that in embodiments with retaining elements such as the embodiment  80  shown in the schematics of  FIGS. 8(   a ) and  8 ( b ), the mechanical energy may be partially of fully be stored in the aforementioned “deploying mechanisms” such as those described for the embodiments  60  and  70  of  FIGS. 6(   a )- 6 ( b ) and  7 ( a )- 7 ( b ), respectively. 
         [0061]    It will also be appreciated by those skilled in the art that the aforementioned deploying mechanisms may be constructed, at least partially, with linkage-type of mechanisms with relatively rigid link components. 
         [0062]    It will be appreciated by those skilled in the art that in all the above embodiments, the sealed volume forming layer may be kept (locked) in its pre-deployed (‘flattened”) configuration (e.g.,  13  in FIGS. ( 1   b ) and ( 2 ),  35  in  FIG. 3(   a ),  46  in  FIG. 4(   b ),  51  in  FIGS. 5(   b ) and  62  in  FIG. 6(   a )) or in its partially deployed configuration (e.g.,  18  in  FIGS. 1(   c ) and  39  in  FIG. 3(   d )) by at least one “retaining” element. The retaining element may in turn be kept in place by the sealed volume increasing layers and/or may be secured to the sealed volume forming layers and/or the adhesive bands described for the above embodiments. 
         [0063]    It will be appreciated by those skilled in the art that all embodiments may also be provided with fluid absorbent layers (elements) such as the fluid absorbent layer  22  of the embodiment  10  of  FIG. 2 , which can be medicated for infection prevention purposes. 
         [0064]    It will also be appreciated by those skilled in the art that all embodiments may also be provided with at least one sharp puncturing tip  23  over the surface under the volume forming layer, such as the sharp puncturing tips  23  of the embodiment  10  of  FIG. 2 . In addition, the area around the puncturing tip(s) of the fluid absorbent material layer may similarly be provided with local anesthetic medication so that the blister puncturing action becomes painless to the patient. 
         [0065]    It will also be appreciated by those skilled in the art that all disclosed blister dressings can be provided with a protective and readily removed layer (preferably a medical grade plastic layer that is readily separated from the adhesive band—various types of which are well known in the art) before packaging. The assembled blister blessing is preferably sterilized and encased in a protective layer to maintain their sterilization. 
         [0066]    It will also be appreciated by those skilled in the art that every one of the sealed volume forming layers of the disclosed embodiments may be provided with a port (such as the port  88  shown in the embodiment  80  of  FIG. 8(   b )) to allow the volume  87  of the deployed sealed volume forming layer  86  to be connected to an external vacuum source (not shown). The port  88  is preferably provided with a one-way valve so that when it is disconnected from the said external vacuum source, air and/or other contaminants would be prevented from entering the volume  87 . 
         [0067]    The port  88  can also be the type which allows puncturing by a needle which seals around the needle and reseals when the needle is removed (such as the ports used on medicament vials). Therefore, medicament, or other therapeutic agent such as saline etc., can be applied to the blister through the port or withdrawn from the volume through the port. A vacuum can also be applied though such port, such as by withdrawing the piston of a needle syringe which pierces the port. Such can be used to increase the vacuum in the volume or withdraw any fluids in the volume or introduced into the volume. Such a port can be used on any of the embodiments described herein. 
         [0068]    While there has been shown and described what is considered to be preferred embodiments of the invention, it will, of course, be understood that various modifications and changes in form or detail could readily be made without departing from the spirit of the invention. It is therefore intended that the invention be not limited to the exact forms described and illustrated, but should be constructed to cover all modifications that may fall within the scope of the appended claims.