Patent Publication Number: US-8992449-B2

Title: Method of making compression sleeve with structural support features

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuation of U.S. Ser. No. 13/294,289, filed Nov. 11, 2011, issued as U.S. Pat. No. 8,622,942, which is a continuation of U.S. Ser. No. 11/733,101, filed Apr. 9, 2007, issued as U.S. Pat. No. 8,070,699, the entireties of which are incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention is directed generally to a compression device for applying compression therapy to a body part of a wearer, more particularly a compression sleeve. 
     BACKGROUND OF THE INVENTION 
     A major concern for immobile patients and like persons are medical conditions that form clots in the blood, such as, deep vein thrombosis (DVT) and peripheral edema. Such patients and persons include those undergoing surgery, anesthesia, extended periods of bed rest, etc. These blood clotting conditions generally occur in the deep veins of the lower extremities and/or pelvis. These veins, such as the iliac, femoral, popiteal and tibial return deoxygenated blood to the heart. For example, when blood circulation in these veins is retarded due to illness, injury or inactivity, there is a tendency for blood to accumulate or pool. A static pool of blood may lead to the formation of a blood clot. A major risk associated with this condition is interference with cardiovascular circulation. Most seriously, a fragment of the blood clot can break loose and migrate. A pulmonary emboli can form from the fragment potentially blocking a main pulmonary artery, which may be life threatening. The current invention can also be applied to the treatment of lymphedema. 
     The conditions and resulting risks associated with patient immobility may be controlled or alleviated by applying intermittent pressure to a patient&#39;s limb, such as, for example, a leg to assist in blood circulation. For example, sequential compression devices have been used, such as the device disclosed in U.S. Pat. No. 4,091,864 to Hasty. Sequential compression devices are typically constructed of two sheets of material secured together at the seams to define one or more fluid impervious bladders, which are connected to a source of pressure for applying sequential pressure around a patient&#39;s body parts for improving blood return to the heart. The inflatable sections are covered with a laminate to improve durability and protect against puncture. As part of the compression device, the two sheets are structurally designed to withstand a changing pressure over time under repeated use. 
     The impermeability of the sleeve makes it uncomfortable for the patient because moisture (i.e. perspiration) is trapped between the impermeable sheet and the patient&#39;s body part. This leads to the patient&#39;s unwillingness to wear the sleeve, thereby, endangering the health of the patient. Moreover, the sleeve is generally non-stretchable and bulky because the bladders must be able to retain a significant amount of fluid pressure during treatment. Thus, the prior art sleeves restrict the mobility of the patient. Also chafing of a patient&#39;s limb can occur because the prior art designs retain the inflatable bladders in a fixed position when under pressure. As the pressure changes during treatment, the bladders press and release against the patient&#39;s limb, rubbing and chafing the skin. A bladder may wrinkle or fold which can cause further irritation during a compression cycle. The final construction of a prior art sleeve is bulky, rigid and may feel heavy to a person over an extended period of use. The present invention is directed to solving the above mentioned deficiencies without compromising durability and clinical effectiveness. 
     As stated above, prior art devices are constructed for durability and strength. As shown in U.S. Patent Publication No. 2005/0187503 A1 to Tordella, Tordella describes a sleeve with a top and bottom sheet. The sheets are fixed at the perimeter to form an inflatable section or bladder, as shown in  FIG. 2 . The material forming the chambers or bladders is polyvinyl chloride or polyethylene. These materials are impervious to moisture as they need to be fluid tight and thick enough to withstand thousands of compression cycles without bursting. Tordella provides some cooling when the device provides for vent holes placed about the sleeve. Also, a slit is introduced through the sheets, but Tordella&#39;s slit is not within the area defined by the chambers (i.e. bladders). Generally, access to skin will provide evaporation of bodily fluids collected at the openings, but the Tordella invention does not provide for removing fluid trapped beneath the impervious sheet away from the openings. The evaporation is limited to the openings and the immediate area under the impervious sheet near the opening. At least some of the embodiments of the present invention provide a solution to the problem of trapped fluid by moving the fluid from underneath the impervious sheet, at a sufficient rate, to a plurality of openings positioned, sized and shaped to maintain blood flow and evaporate the moisture as described below. The Tordella sleeve construction is similar to the Model 9529 SCD Express device (knee length sleeve) available in the United States from Tyco Healthcare Group L.P., which is discussed in more detail below. 
     There are other prior art attempts to improve comfort through breathability and evaporation. U.S. Pat. No. 3,824,492 to Nicholas is directed to a garment that provides pulsating pressure to a lower extremity. A number of holes are placed at the toe area. Air entering the holes is pulled across the patient&#39;s skin through an air space provided by the device when worn. Nicholas has a hard outer shell. The Nicholas device suffers from a number of drawbacks not found in the present invention. The compression sleeves of at least some embodiments of the present invention are elastic, at the inner layer and outer layer, to improve patient mobility and flexure. Instead of a hard outer shell like Nicholas, the present invention has in some embodiments a breathable, soft and elastic outer covering. The elastic outer cover of the present invention helps the sleeve conform to the limb under pressure. The present invention does not have the structure for a channel at the skin to move air across the skin and into the ambient environment. 
     Hasty (U.S. Pat. No. 4,091,804) and Annis (U.S. Pat. No. 4,207,876) disclose a plurality of openings in communication with a ventilation channel. Air is forced through the channel and openings onto the skin by a compressor. The present invention does not use a ventilation channel within the layers of the sleeve. Furthermore in preferred embodiments of the present invention, the compression sleeve does not use its compressor to force the air through the openings onto the skin though the channel. In embodiments of the present invention, air at the openings interfaces with the wicking material to evaporate wicked moisture as described more fully below. The transport mechanism can be the wicking material in present invention. Other devices such as Jacobs (U.S. Pat. No. 5,489,259), provide for direct access to a portion of the patient&#39;s limb, but the Jacobs&#39; device suffers in that cooling (evaporation) is limited to the localized openings. The Neal reference (U.S. Pat. No. 5,693,453), describes openings of various geometries, but the size, shape and distribution is a matter of convenience of use. The Neal device is not directed to prophylaxis treatment. 
     Breathability is associated with cooling through evaporation, as air must be allowed to pass over the openings to the skin. Faster evaporation can occur if a device can breathe through its outer layer which is a problem not solved in the cited references. A number of cited references mention breathing to avoid sweat build-up, but none of the references are directed to providing prophylaxis treatment using sequential compression. A device to Hall (U.S. Pat. No. 6,520,926), describes a support socking that is breathable, but Hall provides no additional detail on how it is made breathable. A device to Roth (U.S. Pat. No. 7,044,924), describes that various sized holes may be punched through both the inner and outer sheet  202 / 204 , between adjacent seams  234  or  242  to allow for ventilation. Further, a moisture-wicking lining material may be applied to the surface of the inner sheet  204  for comfort. The lateral seams  230 ,  232  and  234  and the longitudinal seams  238  and  240  form a plurality of inflatable bladders  250 . The Applicants adapt their inner sheet to provide wicking properties because the Applicants discovered laminating or applying the wicking material to a sheet may compromise the wicking ability of material. The fibers of the wicking material would be interrupted, made discontinuous by the lamination; therefore, interfering with the capillary action of the wicking fibers as described below. 
     Roth may introduce a low pressure area adjacent to bladders which has been shown to promote blood pooling. The Applicants particularly structured at least some embodiment of their device to avoid blood pooling by configuring adjacent bladders to minimize low pressure areas between the adjacent bladders. Applicant&#39;s device was demonstrated to maintain clinical efficacy as described below. Roth does not provide any information regarding the clinical efficacy of its device and does not provide any figures showing its openings or its wicking material. A sock device to Linnane (U.S. Patent Publication No. 2006/0010574), describes a compression stocking with a wicking material near the person&#39;s skin for wicking moisture along channels to the outside of the stocking. The present invention directs moisture to a plurality of openings sized, shaped, and located along the compression device for maximizing evaporation while maintaining clinical efficacy. 
     Elasticity is found in the prior art and is commonly understood to be an important benefit for compression stockings such as the T.E.D®, sold by the assignee of the present invention. A drawback of the prior art sequential compression devices, like that shown in Hasty, is that the bladder material is flexible but not elastic. The prior art bladders are formed as part of a laminated construction adding further rigidity and durability. The Tordella reference discloses a sleeve with flexible, elastic sections between the inflatable sections or portions to facilitate mobility of a patient. Tordella does not disclose an elastic design circumferentially and longitudinally along the sleeves entire length, which is solved by the present invention. 
     The present invention helps overcome patient discomfort without decreasing clinical effectiveness, as shown in supporting lab tests disclosed in this application. An important objective is to improve patient compliance, defined as using the sleeve as prescribed by a doctor. There is a direct correlation of patient compliance with patient comfort. Compliance with mechanical compression devices has always been a concern in healthcare. A clinical staff is overworked with patient loads and duties and thus one-on-one patient care time is at a premium. Often it has been reported that patients, will become uncomfortable wearing compression sleeves and request that the sleeves be taken off, even though they may be necessary to prevent a fatal occurrence of a pulmonary embolism. Clinical staff may not have time to fully educate the patient on the importance of wearing the sleeve, and may not have the time to ensure that the patient is constantly wearing the sleeve. For example, a research study performed by the CMAJ Clinical Practice Guidelines for the Care and Treatment of Breast Cancer, discussed treating lymphedema associated with breast cancer. The study indicates patients are not compliant because the devices are generally difficult to use and not comfortable. It is this reason that compression sleeve manufacturers are trying to introduce more comfortable sleeves while maintaining the clinical efficacy already found in the prior art devices. With the need for shorter stays at the hospital and more outpatient surgery, the need for more a comfortable device that is easier to use, while maintaining clinical efficacy, is a long-felt need in the industry. 
     As stated above there is a long felt need, not found in prior art sleeves for improving comfort without compromising clinical effectiveness. Other prior art devices on the market, such as Aircast®, Huntleigh®, and Hill-Rom® suffer from a number of drawbacks, disclosed below, and solved in the present invention. Preferred embodiments of the present invention provide substantial cooling without compromising the clinical efficacy of the prior art devices such as Kendall&#39;s Model 9529 and 9530 compression sleeves in providing prophylaxis DVT. The present invention is directed to improving patient comfort and thus compliance in terms of physician prescribed use. The following list of features is included in the construction of at least some embodiments of the present invention: soft, cool, easy to use and apply, non-irritating, flexible, fit a patients changing needs, and improved patient compliance. 
     The present invention in its preferred embodiments is engineered to provide the maximum amount of evaporation, which is a function of wicking properties and opening size, location and shape, while minimizing any negative impact on blood flow augmentation or clinical efficacy. Blood flow is dependent on opening size, shape and location, that is, the opening properties must be minimized not to interfere with blood flow, while maximizing the evaporation of trapped moisture beneath the impervious layer. 
     As is known in the art, a compression sleeve is used to provide prophylaxis treatment to a wearer&#39;s body part. This treatment is to help prevent the formation of blood clots by increasing the velocity of blood, in a cascading manner along a limb toward the heart. The illustrated and described embodiments of the present invention wrap around the full circumference around a patient&#39;s limb. The embodiments of the present invention are not limited to full wrap devices. The structural changes that accomplish the features described below will enhance the comfort and use of the prior art devices, but not necessarily at the expense of their claimed clinical efficacy. 
     SUMMARY OF THE INVENTION 
     In one aspect, a method of forming a compression sleeve for being wrapped around a leg of a wearer generally comprises securing two layers of flexible material together to at least partially define first and second adjacent flexible sections. The securing of the two layers of flexible material comprises securing two bladder layers together to define a first inflatable bladder and a second inflatable bladder disposed more proximally than the first inflatable bladder when the sleeve is wrapped around the leg. The first bladder forms at least a part of the first flexible sleeve section and the second bladder forms at least a part of the second flexible sleeve section. The method further includes securing a structural component to the sleeve such that the structural component extends generally between the first and second adjacent flexible sections to maintain a spacing between the sleeve sections lengthwise of the leg when the sleeve is wrapped around the leg. And joining the bladder layers together at least at two weld points on opposite sides of the structural component to locate the structural component on the sleeve so as to maintain the spacing of the adjacent sleeve sections. 
     In another aspect, a method of forming a compression sleeve for being wrapped around a leg of a wearer generally comprises securing two layers of flexible material together to at least partially define first and second adjacent flexible sections. The securing of the two layers of flexible material comprises securing two bladder layers together to define a first inflatable bladder and a second inflatable bladder disposed more proximally than the first inflatable bladder when the sleeve is wrapped around the leg. The first bladder forms at least a part of the first flexible sleeve section and the second bladder forms at least a part of the second flexible sleeve section. A structural component is secured to the sleeve such that the structural component extends generally between the first and second adjacent flexible sections to maintain a spacing between the sleeve sections lengthwise of the leg when the sleeve is wrapped around the leg. The securing of the two layers of flexible material together further forms a connecting section defining a knee opening for being located at a knee of the wearer. The connecting section defines bridge members disposed on opposite sides of the knee opening between the adjacent flexible sleeve sections. The structural component extends through one of the bridge members. The method further comprises joining the bladder layers together at a first pair of spot welds on opposite sides of the structural component at a first location and at a second pair of spot welds on opposite sides of the structural component at a second location spaced from the first location to locate the structural component on the sleeve so as to maintain the spacing of the adjacent sleeve sections. 
     In yet another aspect, a method of forming a compression sleeve for being wrapped around a leg of a wearer generally comprises securing two layers of flexible material together to at least partially define first and second adjacent flexible sleeve sections. A structural component that is more rigid than the flexible material to the sleeve is secured between the first and second flexible sleeve sections so that the structural component extends between the first and second flexible sleeve sections to maintain a spacing between the sleeve sections lengthwise of the leg when the sleeve is wrapped around the leg. The structural component has opposite ends that are wider than a middle portion of the structural component. 
     Other features will be in part apparent and in part pointed out hereinafter. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a front elevation of one embodiment of a compression sleeve with an outer cover and intermediate layers of the sleeve partially removed to show underlying layers; 
         FIG. 2  is an exploded perspective of the compression sleeve; 
         FIG. 3  is a rear elevation of an inner layer of the compression sleeve; 
         FIG. 4  is a front elevation of the compression sleeve with the outer cover removed; 
         FIG. 5  is a longitudinal section of the compression sleeve with inflatable bladders of the sleeve in an inflated state; 
         FIG. 6  is a longitudinal section of the compression sleeve with the inflatable bladder in a deflated state; 
         FIG. 7  is an enlarged fragmentary elevation of the outer cover illustrating loop material; 
         FIG. 8  is an exploded perspective of another embodiment of a compression sleeve; 
         FIG. 9  is a front elevation of the compression sleeve of  FIG. 8  with an outer cover removed; 
         FIG. 10  is an exploded perspective of another embodiment of a compression sleeve; 
         FIG. 11  is a front elevation of the compression sleeve of  FIG. 10  with an outer cover removed; 
         FIG. 12  is a front elevation of another embodiment of a compression sleeve, similar to the embodiment of  FIG. 11 , with an outer cover removed; 
         FIG. 13  is a front elevation of another embodiment of a compression sleeve; 
         FIG. 14  is a front elevation of another embodiment of a compression sleeve with an outer cover partially removed to show intermediate layers and an inner layer; 
         FIG. 15  is a front elevation of yet another embodiment of a compression sleeve with an outer cover partially removed to show intermediate layers and an inner layer; 
         FIG. 16  is a section of another embodiment of a compression sleeve, similar to  FIG. 5  with components of the sleeve being secured together along a single peripheral seam line; 
         FIG. 17  is an enlarged detail of the seam line illustrated in  FIG. 16 . 
         FIG. 18  is a front elevation of another embodiment of a compression sleeve with an outer cover partially removed to show underlying layers; 
         FIG. 19  is a rear elevation of the embodiment of  FIG. 18 ; 
         FIG. 20  is a front elevation of a compression sleeve of another embodiment with an outer cover and intermediate layers of the sleeve partially removed to show underlying layers; 
         FIG. 21  is a graph of a percent of liquid evaporated over time for various compression sleeves including the sleeve of the present invention; and 
         FIG. 22  is a percent of blood flow augmentation at 6% open area per sleeve for various opening shapes. 
     
    
    
     Corresponding reference characters indicate corresponding parts throughout the drawings. 
     DETAILED DESCRIPTION OF THE DRAWINGS 
     Referring now to the drawings, and in particular to  FIGS. 1 and 2 , one embodiment of a compression device (broadly, “a garment or a sleeve”) is generally indicated at for applying sequential compression therapy to a limb of a wearer. The compression sleeve is of the type sized and shaped for being disposed around a leg of the wearer, but could be configured for application to other parts of the wearer&#39;s body. More specifically, the sleeve  10  has a width W ( FIG. 1 ) for being wrapped around a full circumference of the leg and a length L ( FIG. 1 ) for running from the ankle to a thigh of the leg. This type of sleeve is generally referred to in the art as a thigh-length sleeve. It will be understood that a compression sleeve may come in different sizes, such as a knee length sleeve ( FIG. 20 ) that extends from the ankle up the calf of the leg. It is understood that other types of compression devices for being disposed about other limbs of the wearer&#39;s body, are within the scope of this invention, such as a wrap around a patient&#39;s chest in the treatment of breast cancer. 
     A numerical study performed by R. D. Kamm, titled “Bioengineering Studies of periodic External Compression as Prophylaxis Against Deep Vein Thrombosis—Part I: Numerical Studies” concluded, among other things, that “the entire length of the veins should be emptied as full and as rapidly as possible.” The Kamm study reviews three types of compression, the one of interest is wavelike compression. Wavelike compression is most similar to sequential compression provided by the illustrated embodiments of the present invention. The Kamm Study found wavelike compression is most effective in moving blood for an effective prophylaxis treatment. 
     Referring to  FIG. 1 , the compression sleeve  10  comprises four layers secured together in the illustrated embodiment of the present invention. The scope of the present invention is not limited to four layers. More specifically, the compression sleeve comprises an inner layer, generally indicated at  12 , on which a first intermediate layer (broadly, a first bladder layer), generally indicated at  14 , is overlaid. A second intermediate layer (broadly, a second bladder layer), generally indicated at  16 , overlies the first intermediate layer  14  and is secured thereto. An outer cover generally indicated at  18 , overlies and is secured to the second intermediate layer  16 . In use, the inner layer  12  is disposed most adjacent to the limb of the wearer and is in contact with the limb of the wearer, and the outer cover  18  is most distant from the limb of the wearer. A knee opening  19  is formed through the sleeve  10  that is generally aligned with the back of the knee when the sleeve is applied to the leg. The layers have the same geometric shape and are superposed on each other so that edges of the layers generally coincide. It is contemplated that one or more of the layers  12 ,  14 ,  16 , or  18  may not be superposed on a corresponding layer, but slightly offset to accommodate a particular feature of a patient&#39;s limb. Moreover, the number of sheets or thickness making up each layer  12 ,  14 ,  16 , or  18  of the compression sleeve  10  may be other than described. The thickness of the layers may vary to add strength or to cause more expansion in one direction, such toward the limb, during inflation. 
     Referring to  FIGS. 1 ,  2  and  4 , the first and second intermediate layers  14 ,  16 , respectively, each include a single sheet of elastic material (broadly, “bladder material”). For example, the sheets  14  and  16  are made of a pliable PVC material as the bladder material. Layers  12  and  18  are made of a polyester material. The second intermediate layer  16  is secured to the first intermediate layer  14  via three separate bladder seam lines  22   a ,  22   b ,  22   c  defining a proximal bladder  24   a , an intermediate bladder  24   b  and a distal bladder  24   c , respectively, that are spaced apart longitudinally along the sleeve  10 . The number of bladders may be other than three without departing from the scope of the present invention. As used herein, the terms “proximal”, “distal”, and “intermediate” represent relative locations of components, parts and the like of the compression sleeve when the sleeve is secured to the wearer&#39;s limb. As such, a “proximal” component or the like is disposed most adjacent to a point of attachment of the wearer&#39;s limb to the wearer&#39;s torso, a “distal” component is disposed most distant from the point of attachment, and an “intermediate” component is disposed generally anywhere between the proximal and distal components. 
     For reasons discussed below, the proximal bladder  24   a  defines a proximal, lateral extension  25  near the upper edge margin of the sleeve  10 . The bladders  24   a ,  24   b ,  24   c  are circumferential bladders meaning that they are sized and shaped to be wrapped around substantially the entire circumference of the wearer&#39;s limb or very nearly the entire circumference of the limb. For example, in one embodiment the bladders  24   a ,  24   b ,  24   c  each extend around at least 90% of a median circumference of a leg. However, prior art devices have partial bladders such as AirCast® and HillRom®, and these prior art devices do not provide for openings, elasticity and other features of the present invention. It is to be understood that the construction described herein can be adopted by the prior art sleeves with a partial bladder construction, without departing from the scope of the present invention. 
     The intermediate layers  14 ,  16  may be secured together by radiofrequency welding, adhesive, or other chemical and/or mechanical process. It is understood that the intermediate layers  14 ,  16  may be secured together at other locations, such as around their peripheries and at bladder seam lines  22   a ,  22   b ,  22   c  to further define the shape of the inflatable bladders  24   a ,  24   b ,  24   c . For purposes discussed below, the first intermediate layer  14  is secured to the inner layer  12  along a seam line  25  ( FIGS. 5 and 6 ) that runs along the outer periphery of the first intermediate layer  14  so that central regions of the bladders  24   a ,  24   b ,  24   c  are not secured to the inner layer  12 . This permits the bladders  24   a ,  24   b ,  24   c  to move relative to the inner layer  12 . The second intermediate layer  16  may also be secured to the inner layer  12  along the same seam line  25 . The first intermediate layer  14  may be secured to the inner layer  12  by RF welding or adhesive or in other suitable ways. This structure improves comfort as described below. 
     Referring to  FIGS. 2 and 4 , each inflatable bladder  24   a ,  24   b ,  24   c  receives fluid from a source of compressed fluid (not shown) via a dedicated proximal bladder tube  26   a , intermediate bladder tube  26   b , and distal bladder tube  26   c , respectively, ( FIG. 2 ). A tube line need not be dedicated to a bladder to practice the invention. Each tube  26   a ,  26   b ,  26   c  is disposed between the intermediate layers  14 ,  16  and secured to the respective bladder  24   a ,  24   b ,  24   c  by the respective bladder seam line  22   a ,  22   b ,  22   c . As shown best in  FIGS. 2 and 4 , the first intermediate layer  16  defines a cutout  27  ( FIG. 2 ) so that portions of the tubes  26   a ,  26   b ,  26   c  are not disposed between the intermediate layers. Other ways of securing the tubes  26   a ,  26   b , and  26   c  to the bladders  24   a ,  24   b , and  24   c  are within the scope of the invention. The opposite ends of the tubes  26   a ,  26   b ,  26   c  are grouped together using a second connector  30  ( FIGS. 1 and 2 ) that is adapted to fluidly connect the tubes to the source of compressed fluid. The source of compressed fluid may be an air compressor under the control of a microprocessor that sequentially pressurizes the bladders as is generally known in the art. An exemplary air compressor is described in U.S. Pat. No. 5,876,359 to Bock, the disclosure of which is incorporated herein by reference. The bladders  24   a ,  24   b ,  24   c  may be configured to contain air pressurized to at least about 10 mm Hg (1333 Pa) to about 45 mm Hg (6000 Pa). The bladders should be capable of being repeatedly pressurized without failure. Materials suitable for the sheets include, but are not limited to, flexible PVC material that will not stretch substantially. In another embodiment, the intermediate layers may form a chamber for receiving an inflatable bladder that is formed separate from the chamber. In this embodiment, the layers may not be capable of containing pressurized air as along as the inflatable bladders are so capable. It will be noted that the bladders  24   a ,  24   b ,  24   c  can have openings  32  extending completely through the bladders, as described in the embodiments of the present invention. 
     Referring particularly to  FIGS. 1 and 4 , the sleeve  10  defines a connecting section including a pair of bridge members  84  on opposite sides of the knee opening  19  that extend between and connect a proximal portion of the sleeve that includes the proximal bladder  24   a  to the remainder of the sleeve. The proximal tube  26   a  generally lies along an axis of bridge member  84  to provide structural, lengthwise support to the sleeve  10 . As shown best in  FIG. 4 , the cutout  27  in the intermediate sheet  16  does not extend through the bridge member  84 . The proximal tube  26   a  extends between spaced apart distal spot welds  86  disposed adjacent to a distal end of the bridge member  84  and between spaced apart proximal spot welds  88  disposed adjacent to a proximal end of the bridge member. The spot welds secure the tube  26   a  to the bridge member  84  such that the proximal bladder tube  26   a  constitutes a rigid structural component (broadly, a “first rigid structural component”) for maintaining the spacing between the proximal bladder  24   a  and the intermediate bladder  24   b  and in maintaining the longitudinally structural integrity of the connecting section. In other words, the sleeve  10  is rigidified against collapsing or sliding down the wearer&#39;s leg. As explained above, the proximal bladder tube  26   a  is secured to the proximal bladder  24   a  at the proximal, lateral extension  25 . The proximal bladder tube  26   a  runs along a side of a distal portion of the proximal bladder  24   a  so that it does not enter the bladder until it reaches the proximal, lateral extension  25 . Being secured at the proximal, lateral extension  25  of the bladder  24   a  provides additional longitudinal support to the sleeve  10  because the proximal bladder tube  26   a  extends lengthwise across more of the proximal portion of the sleeve than if the tube was secured at a distal portion of the bladder. In one embodiment, the proximal bladder tube  26   a  extends at least a quarter of the way across a thigh section of the sleeve  10 . In another embodiment shown in  FIG. 4 , the tube  26   a  extends more than half way across the thigh section. This helps to keep the proximal portion of the sleeve  10  from collapsing and/or sliding out of position down the wearer&#39;s leg. 
     Referring to  FIGS. 2 and 4 , in addition to the proximal bladder tube  26   a , a second rigid structural component  90 , disposed between the intermediate layers  14 ,  16  and extending within the other bridge member  84  of the connecting section, also provides longitudinal structural support to the sleeve  10 . The second structural component  90  extends between proximal and distal ends of the bridge member  84 . The respective proximal and distal ends of the structural component  90  are wider than an intermediate portion of the component and the periphery of the component generally conforms to the peripheries of side walls of the bridge member  84  so that the structural component is secured to the bridge member. 
     Referring to  FIGS. 1 ,  3  and  4 , the proximal bladder  24   a  is secured to the inner layer  12  and the outer cover  18  at spot welds  92  adjacent to the bladder openings  32  and within an outer perimeter of the bladder defined by the bladder seamline  22   a . The spot welds  92  maintain the outer cover  18  and the inner layer  12  in proper position with respect to the bladders  24   a ,  24   b ,  24   c . In other words, the spot welds  92  prevent the bladders  24   a ,  24   b ,  24   c  from substantially shifting relative to the inner layer  12  and the outer cover  18  while still providing the sleeve  10  with substantial flexibility. Too much movement of inner layer  12  and the outer cover  18  with respect to the bladders  24   a ,  24   b ,  24   c  may reduce the fit of the sleeve, thereby leading to reduced efficacy of the compression therapy. The proximal bladder  24   a  is free from securement to the inner layer  12  and outer cover  18  other than at the spot welds  92  to maintain flexibility of the sleeve so that mobility of the patient&#39;s leg is not compromised. Inner layer  12  may be joined to layer  16  at the spot welds  86 ,  88 ,  92  or the inner layer  12  may be joined at the seam line  34  of the opening  32 . Away from the openings  32  and spot welds  86 ,  88 ,  92 , the inner layer  12  is not joined to surface of the bladder material forming the bladder that expands to provide compression treatment to the patient&#39;s limb. 
     In one embodiment, the bladders  24   a ,  24   b ,  24   c  are constructed to expand more toward the wearer than away from the wearer, thereby applying a greater compressive force on the wearer&#39;s limb. In one example, the first intermediate layer  14  (i.e., the layer most adjacent to the inner layer  12 ) has a lesser thickness than that of the second intermediate layer  16 . With both layers  14 ,  16  being of the same material (i.e., elastic PVC material) the first intermediate sheet will have a lower modulus of elasticity. Thus, when air is introduced into the bladders  24   a ,  24   b ,  24   c , the bladders will expand more toward the inner layer  12  and the wearer than away from the wearer. It is understood that other ways, besides a difference in thickness between the intermediate layers  14 ,  16 , of constructing the bladders  24   a ,  24   b ,  24   c  so that they expand more toward the wearer than away from the wearer is within the scope of the invention. 
     Referring to  FIGS. 2 and 3 , the inner layer  12  is constructed of a material that is capable of wicking moisture near a patient&#39;s limb. The inner (or “wicking”) layer  12 , through capillary action, absorbs moisture trapped near the leg or limb of the wearer, carries the moisture away from the surface of the limb, and transports the moisture from locations on the limb at the inner layer  12  where the moisture is abundant to areas where it is less abundant, at the openings  32 , for evaporation to the ambient environment. The openings may be of various sizes, shapes and locations within the bladder area providing the compression. An opening  32  exposes the wicking layer to the ambient or surrounding air as opposed to the portion of the wicking layer beneath the bladder material. The portions of the inner layer  12  in registration with the openings  32  may be referred to as “exposed portions”. Other ways of exposing the wicking material are within the scope of this invention, such as slits or extending the wicking material outside the perimeter of the bladder material. The present invention has its exposed portion within the bladder area that provides compression. The compression region is the bladder area expanding and contracting under the influence of air pressure or other fluids. The area of the bladder not providing compression is the seamline or weld points which are points of the bladder material sealed together to provide an air or water tight boundary or other regions of the opposed sheets  14 ,  16  outside the perimeter of the bladder. The wicking material  12  may be inter-weaved with the impervious material to form the inner layer  12 . The wicking material  12  transports moisture to an area of less moisture. The openings  32  must be engineered to maintain blood velocity, while maximizing evaporation of moisture. Suitable wicking materials may be comprised of, for example, some form of, polyester, although they may be comprised of polypropylene. Microfibers may be used. Suitable microfiber materials include, but are not limited to, CoolDry model number CD 9604, sold by Quanzhou Fulian Warp Knitting Industrial Co., Ltd., Quanzhou City, Fujian Province, China and CoolMax®, sold by E. I. du Pont de Nemours and Company, Wilmington, Del. 
     A number of lab tests were performed to determine the embodiments of the present invention. The tests looked at the evaporation rate, wicking performance and elasticity to provide improved comfort without compromising blood flow velocity. The study used Kendall&#39;s 9529 knee length sleeve model and three other competitor models denoted as knee length sleeves A, B and C. Third party testing has demonstrated the superior performance of a full length, circumferential wrap such as Kendall&#39;s 9530. The American Journal of Surgery study “Effectiveness of Leg Compression in Preventing Venous Stasis”, concluded a sequential compression device, like Kendall&#39;s 9530 model, is best at moving blood. The study concluded that DVT prophylaxis using the 9530 leg sleeve device encounters fewer issues and problems than administering a drug such as Heparin, and the leg sleeve device was proven, to move contrast media injected in the blood along the patient&#39;s leg more effectively than the other methods described in the article. 
     As discussed above, the structural changes were directed to a sleeve that is softer; cools itself without compromising blood flow; is easy to use and apply; effectively eliminates irritation and pressure points; is flexible and elastic to improve patient mobility and is overall compliant with the existing expectations for clinical efficacy. To improve softness the wicking material, at the inner layer  12 , was chosen to be a knitted sheet rather than an impervious non-woven such as polyvinyl chloride. 
     Cooling is achieved in at least one embodiment by a combination of wicking material and the openings  32 . The openings allow for evaporation of the wicked moisture from a patient&#39;s limb. The wicking material  12  or inner layer was tested for the amount of fluid it could absorb from the patient&#39;s skin based on the assumption that the area between the skin and the inner layer  12  would be laden with sweat. This is called the wicking rate in terms of moisture absorbed. Once the wicking material absorbed moisture, the next wicking test is how far the material could move the absorbed moisture. This is called the wicking rate in terms of distance. The wicking rate in terms of distance is important because it impacts the location and number of openings  32 ,  34  in a bladder. Increasing the size and number of openings  32  impacts blood flow, as shown in  FIG. 22 , when the bladder pushes against the patient&#39;s limb to move blood to the heart. Findings at  FIG. 22  suggest larger openings provide the highest blood flow, but a larger opening may cause blood pooling. The importance of the opening characteristics is described below. 
     The next test was the amount of open bladder space as a percentage of the sleeve area for maximum evaporation and still be considered a compliant device. This is called the % Opening to Patients Skin. The % Open to Patients Skin (through the bladder) was maximized to improve evaporation, while maintaining a clinical efficacy of blood flow—as found in the Model 9529 sleeves currently sold by Kendall. It is beneath the bladder where the moisture and heat are trapped, which provides the discomfort to the patient. 
     To summarize the evaporation improvement of a certain embodiment of the present invention, Table I is presented. 
     
       
         
           
               
             
               
                 TABLE I 
               
             
            
               
                   
               
               
                 Comparison of Sleeve Evaporation 
               
            
           
           
               
               
               
               
               
               
            
               
                   
                   
                 Circumfer- 
                 % 
                   
                   
               
               
                   
                   
                 ential 
                 Opening 
                   
                   
               
               
                   
                   
                 Wrap of the 
                 to Patients 
                 % 
                 % 
               
               
                   
                   
                 Bladder 
                 Skin 
                 Evaporation 
                 Evaporation 
               
               
                   
                   
                 around 
                 through 
                 of moisture 
                 of moisture 
               
               
                 Sleeve 
                 Type 
                 the Limb 
                 bladder 
                 at 1 hour 
                 at 8 hours 
               
               
                   
               
               
                 9529 
                 Knee 
                 Yes 
                 0% 
                 ~5%  
                 12-18% 
               
               
                 Sleeve 
                 Knee 
                 Yes 
                 ~6%   
                 15% 
                 80-85% 
               
               
                 of the 
                   
                   
                   
                   
                   
               
               
                 Present 
                   
                   
                   
                   
                   
               
               
                 Invention 
                   
                   
                   
                   
                   
               
               
                 Sleeve A 
                 Knee 
                 No 
                 0% 
                 35% 
                 90-95% 
               
               
                 Sleeve B 
                 Knee 
                 Yes 
                 0% 
                 ~5%  
                 35-40% 
               
               
                 Sleeve C 
                 Knee 
                 No 
                 0% 
                 25% 
                 80-85% 
               
               
                   
               
            
           
         
       
     
     The sleeves tested were the Kendall model 9529, a sleeve constructed according to the principles of the present invention as an improvement to the 9529 or 9530 models, a Hill Rom® ActiveCare knee length sleeve, a Huntleigh® Flowtron sleeve and an AirCast® VenaFlow calf cuff. The competitor sleeves are represented as Sleeve A, B or C in the table. Table I demonstrates the unexpected results of the tested embodiment of the present invention. The tested embodiment of the present invention improves evaporation at least three times over the 9529 model within the first hour. At eight hours, the evaporation is about six times more than the 9529 model. The compression sleeve constructed according to the principles of the present invention gave final results comparable to Sleeves A and C, which do not have bladders that extend circumferentially around a limb or leg. The rate of evaporation is about 10% liquid evaporated per hour for the sleeve of an embodiment of the present invention as compared to the 9529 model at 1.35% rate. The % Liquid Evaporated over time is presented in  FIG. 21 . 
     The testing used new sleeves. All sleeves are knee length. For the tested embodiment of the present invention, the knee length sleeve is shown in  FIG. 20 . The moisture loss due to evaporation is dependent on the wicking properties of the inner layer  12 , and the location, and size of the openings as well as their distribution pattern along and around the sleeve as shown in the inverted waterdrop configuration of  FIG. 1 . 
     The wicking test was devised to characterize the absorption and movement of wicked fluid at the inner layer of the SCD Express device sold by the Assignee of the present application. First the Applicant will describe the wicking test procedure. The results of the wicking test have been tabulated and are discussed hereinafter. The wicking material is the vehicle to absorb and move the otherwise trapped fluid beneath the impermeable bladder layer to the openings or external to the inside of the sleeve. 
     The optimal wicking rate and distance is dependent on the opening size and location which impacts blood flow or treatment. Kamm, described previously herein, reached the conclusion that the entire length of the veins should be emptied and filled as rapidly as possible. This does not mean a partial bladder can not meet the Kamm result, but too many openings in a full circumferential body wrap can introduce blood pooling. Thus, the key is to prevent blood pooling, which means the device is moving blood toward the heart, while maximizing cooling by maximizing the size and number of openings throughout the body wrap. The pattern of the openings  32  can help to maximize the number of openings by arranging the waterdrops as shown in  FIG. 1  and  FIG. 4 . 
     Next, the Applicant evaluated and determined the size, type, location and number of openings for evaporating the wicked fluid. The opening size and location impacts comfort and blood flow. Too many openings may interfere with placing the sleeve on the limb because the sleeve is too loose and will not conform to the body part. Too many openings can reduce overall blood velocity. The pressure applied is directly related to blood velocity, that is, less pressure corresponds to lower flow rates of blood and uneven pressure may cause blood to pool at the openings. The sleeve pressure may act as a tourniquet if not properly placed on the user. Too many openings can cause adjacent bladder areas to fold on one another creating a possible tourniquet effect when secured using the hook and loop straps or flaps. If the openings are too large, this will lead to low pressure areas which can possibly lead to the pooling of blood. 
     The wicking test is used to experimentally quantify the wicking capability (i.e. absorption and movement) needed at the inner layer  12  of the compression sleeve  10 . First, a sample is cut from the inner layer of the tested embodiment of the present invention and the prior art 9529 sleeve. The sample has a length of 6 in (15.24 cm) and a width of 0.75 in (1.91 cm). Other lengths may be used. The sample is marked with a longitudinal centerline so that the length of the strip is divided into two 3 in (7.62 cm) portions. The sample is weighed, and its weight is recorded as a starting weight. The sample is attached to a lab stand or other structure. The lab stand has an arm extending horizontally from a vertical post. The vertical position of the arm on the post is adjustable. The sample is attached adjacent to the free end of the arm so that the length of the sample extends downward, substantially perpendicular to the arm. 
     A 400 ml beaker of wicking fluid is placed underneath the sample as it hangs from the lab stand. The wicking fluid is room temperature tap water with red food coloring added for contrast against the sample. With the beaker underneath the sample, the lab stand arm is lowered so that the sample is submerged into the wicking fluid to the centerline of the sample. The sample remains submerged for 60 seconds. After 60 seconds, the lab stand arm is raised to completely withdraw the sample from the wicking fluid. The sample remains above the beaker for 10 seconds to allow any excess absorbed fluid to drip off. After 10 seconds, the sample is cut in half at its centerline and the lower half of the sample (i.e., the portion of the sample that was submerged in the wicking fluid) is discarded. The other half of the sample (i.e., the top portion) is weighed on a digital scale with a precision of 1/100th gram. This weight is recorded, and the weight of the fluid that was wicked is calculated by subtracting the original half-weight of the sample from the weight of the top portion after wicking. The sample is laid on a plastic sheet, and the distance the wicking fluid progressed is measured from the cut end (i.e., the centerline) to the highest point to which the wicking fluid progressed. This distance is recorded. 
     After recording the progression of the wicking fluid, the sample remains untouched on the plastic sheet for 60 minutes at ambient room temperature conditions. After 60 minutes, the distance from the cut end of the top portion to the highest point to which the wicking fluid progresses is measured. This distance is recorded. Next, the top portion is weighed on the digital scale, and its weight is recorded. 
     Using the recorded data above, the average wicking rate is determined in terms of wicking distance for the material used at the inner layer, according to the following equation:
 
 WD   60s /60s=distance/s,
 
     where WD 60s  is the average wicking distance of the four samples after 60 seconds. 
     Moreover, the average wicking rate in terms of amount of fluid wicked at the inner layer is calculated according to the following equation:
 
 WW   60s /60s=amount wicked( g )/s,
 
     where WW 60s  is the average weight of the fluid wicked by the four samples after 60 seconds. 
     Using the above testing approach, the wicking capabilities of CoolDry model number CD9604 were determined. Four samples are cut from a sheet of the CoolDry model number CD9604, and the samples were weighed. A sample each has a dry weight of 0.40 grams, so that the half-weight, and therefore, the original weight of the top portion, is 0.20 grams. The mean weight of the top portion of the samples after 60 seconds in the wicking fluid totaled 0.49 grams, with the largest observed weight at 0.50 grams and the smallest weight at 0.48 grams. The mean weight of the fluid wicked is 0.29 grams for a sample. The mean wicking distance for the top portion of the samples after 60 seconds in the wicking fluid is 2.25 in (5.72 cm), with the largest distance recorded at 2.31 in (5.88 cm) and the smallest distance recorded at 2.19 in (5.56 cm). The mean weight of the top portion after 60 minutes at ambient room conditions is 0.213 grams, with the largest weight recorded at 0.22 grams and the smallest weight recorded at 0.21 grams. The mean wicking distance for the top portion after 60 minutes at ambient room conditions is 2.82 in (7.16 cm), with the largest distance recorded at 3.00 in (7.62 cm) and the smallest distance recorded at 2.63 in (6.68 cm). 
     Using the above data and equations, the average wicking rate in terms of distance (WD 60s ) is about 0.0375 in/s (0.09525 cm/s). The average wicking rate in terms of amount of fluid wicked (WW 60s ) is about 0.0048 g/s. The determined wicking rate and distance allows one to engineer the openings  32  about the sleeve for improving comfort while maintaining clinically acceptable blood flow. The mere inclusion of wicking material does not ensure the cooling affect to the patient. The wicking rate and distance must be correlated with the opening characteristics to ensure clinically effective blood flow augmentation, as tabulated in  FIG. 22 . 
     Preferably, the inner layer  12  has an average wicking rate in terms of distance (WD 60s ) that is at least about 0.01 in/s (0.0254 cm/s) and an average wicking rate in terms of weight of fluid wicked (WW 60s ) of at least about 0.002 g/s. 
     The construction of wicking layer, openings, bladder and outer layer is discussed. The openings must be sized and shaped to maintain the blood flow efficacy of a compression sleeve like model 9529 and to provide improved evaporation of moisture for increasing patient compliance. Referring to  FIGS. 1 and 4 , the sleeve  10  is constructed so that portions of the intermediate layers  14 ,  16  do not overlie the inner layer  12  so that moisture wicked by the inner layer  12  travels to open portions of the inner layer  12  and evaporates to the atmosphere. In this illustrated embodiment, each inflatable bladder  24   a ,  24   b ,  24   c  includes openings  32  that extend through the first and second intermediate layers  14 ,  16 , respectively, to the inner layer  12 . One way to form such an opening is to seal the intermediate layers  14 ,  16  together within the periphery of the respective bladder  24   a ,  24   b ,  24   c  using a continuous sealing line  34 . The portions of the intermediate layers  14 ,  16  within a periphery of the sealing line  34  can be removed, such as by cutting, thereby forming the openings  32 . Other ways of forming the openings  32  are within the scope of this invention. Once an opening size and pattern is determined, a metal die is cast to cut the openings in the PVC bladder material for the opposing sheets. 
     For the preferred embodiment, the opening shape is generally shaped like a waterdrop. Each opening  32  is tapered from a first round end portion toward a second, smaller round end portion. The openings  32  may be of other shapes, such as circles, ovals, and slits, without departing from the scope of the invention. The opening shapes may be inter-mixed at the bladder without departing from the scope of the invention. The waterdrop-shape provided the clinically efficacy, as found in  FIG. 22 , and this shape allowed for the largest number of openings within the available area without compromising the structural integrity of the bladder. The available bladder area varies from sleeve to sleeve because of seam line placement and other features. The more openings, at the same area per an opening, the greater area of the sleeve or body wrap that is available for evaporation. The circle and larger waterdrop-shape provide for larger low pressure, than the medium water-drop shape of the present. As stated above, low pressure areas as susceptible to the pooling of blood. Table II shows the medium waterdrop-shape as the preferred shape for the present invention. Other shapes are possible for compression devices of different shapes and sizes. The opening shape, size and distribution defining the % Open Area are proportional to the bladder size. As stated in the present invention, the Applicants determined about 6-10% Open Area per a Sleeve is preferred for maintaining clinical efficacy, while improving evaporation or cooling for patient comfort. 
     The water-drop shape has one of the highest number openings for the device as shown in  FIGS. 1 and 20 . Also, the area per an opening demonstrated good structural integrity upon wrapping as well as a shape that allowed an evenly distributed pattern at the sleeve. This provides for an optimal number of points of evaporation at a low % Open Area of a Sleeve, but not too low of % Open Area such that evaporation will not occur at a rate that improves patient comfort, thus, compliance. The more openings the less distance wicked moisture will need to travel to reach the atmosphere from beneath the layers of non-woven material. 
     
       
         
           
               
             
               
                 TABLE II 
               
             
            
               
                   
               
               
                 Opening Shape Characteristics 
               
            
           
           
               
               
               
               
            
               
                   
                 Open Area per 
                 # of Opening 
                 Open Area of 
               
               
                 Opening Shape 
                 a Opening 
                 at a Sleeve 
                 a Sleeve 
               
               
                   
               
            
           
           
               
               
               
               
            
               
                 0529 Oval 
                 0.81 
                 23 
                 6.7% 
               
               
                 0529 Small Waterdrop 
                 0.27 
                 27 
                 2.6% 
               
               
                 0529 Medium 
                 0.61 
                 27 
                 5.9% 
               
               
                 Waterdrop 
                   
                   
                   
               
               
                 0529 Large Waterdrop 
                 1.08 
                 20 
                 7.7% 
               
               
                 9529 SCD Express 
                 0 
                 0 
                 0.0% 
               
               
                 0592 Circle 
                 0.81 
                 23 
                 6.7% 
               
               
                   
               
            
           
         
       
     
     The opening size correlated with the wicking rate and distance determines the evaporation of the wicked moisture. 
     Referring to  FIG. 22  the blood flow augmentation of the medium waterdrop is substantially similar to the knee-length 9529 sleeve at 6% Open Area of a Sleeve. This means the clinical efficacy is maintained while substantially improving comfort. 
     The measured blood flow augmentation is the amount of additional blood moved with treatment, sequential compression, as compared to no treatment. No treatment would be the blood flow of the patient at rest. Blood flow augmentation, in its measure, includes blood velocity and blood vessel diameter of a patient. Blood flow augmentation is a more accurate measure because it removes the affect of differing blood vessel size between the patients. Another measure is peak velocity augmentation. This is a measure of the highest blood flow velocity reached during a treatment cycle. The faster the velocity the more shear imparted to the blood to help prevent the formation of blood clots. 
       FIG. 22  shows the compression sleeve having a 6% open area and medium waterdrop-shaped openings each having an area of about 0.6 in 2  is most similar to the current clinical efficacy of Kendall&#39;s 9529 model. The sleeve having the medium waterdrop-shaped openings produced a blood flow augmentation substantially at the 9529 SCD Express level while increasing evaporation of moisture more than 10% after one hour of use compared to the current 9529 model sleeve. The peak velocity of the sleeve having the medium waterdrop-shaped openings and the 9529 device were within percentage points of each other, while the circle was the closest. Though the sleeve having the large waterdrop-shaped openings produced the greatest blood flow augmentation, the medium waterdrop-shaped openings are preferred because the large open areas of the large waterdrop-shaped openings will likely cause blood pooling. The results of Kamm, and the findings of Nicolaides, Olson and Best suggested the more sleeve area providing compression the less likely there is the possibly of blood to pool. Blood pooling is caused by a localized area of low pressure created by openings or such features between areas of higher pressure. 
     As derived from the evaporation and hemodynamic testing, each waterdrop-shaped opening has an area between about 0.50 in 2  (3.23 cm 2 ) and about 0.90 in 2  (5.81 cm 2 ), and preferably about 0.61 in 2  (3.94 cm 2 ). In one example, the openings  32  comprise between about 2% and about 20% of the total surface area of the respective inflatable bladder, and more preferably between about 4% and about 15% of the total surface area of the respective inflatable bladder  24   a ,  24   b ,  24   c . Each opening  32  may comprise between about 0.5% and about 1.2% of the total surface area of the respective bladder  24   a ,  24   b ,  24   c . The total percent surface occupied by the openings is calculated by summing the areas of the openings and dividing the sum by the total surface area of the uninflated bladder, where the total surface area of the uninflated bladder includes the areas of the openings. The percent surface area occupied by each opening is the area of that one opening divided by the total surface area of the uninflated bladder, where the total surface area of the uninflated bladder includes the areas of the openings. 
     It is understood that the percentage of openings  32  may depend on the type of compression sleeve. In an embodiment for a thigh-length compression sleeve, such as the illustrated sleeve, the openings more preferably comprise between about 4% and about 6% of the total surface area of the respective bladder. For example, in the illustrated embodiment, the openings  32  in the distal bladder  24   c  comprise about 4.36% of the total surface area of the respective inflatable bladder; the openings in the intermediate bladder  24   b  comprise about 5.00%; and the openings in the proximal bladder  24   c  comprise about 5.96%. Each opening  32  may comprise between about 0.5% and about 1.0% of the total surface area of the respective inflatable bladder. For example, in the illustrated embodiment, each opening  32  in the distal bladder  24   c  comprises about 0.87% of the total surface area of the respective inflatable bladder; each opening in the intermediate bladder  24   b  comprises about 0.72%; and each opening in the proximal bladder  24   c  comprises about 0.60%. In the illustrated embodiment, the total surface areas of the distal, intermediate and proximal bladders are 70.01 in 2  (451.68 cm 2 ), 81.05 in 2  (522.90 cm 2 ) and 102.42 in 2  (660.77 cm 2 ), respectively. For example, the sleeve can have at the distal bladder  24   c  5 openings; at the intermediate bladder  24   b  7 openings; and at the proximal bladder  24   a    10  openings. Moreover, all of the openings have the same area of 0.61 in 2  (3.94 cm 2 ). An opening&#39;s area may vary from opening to opening. 
     In an embodiment for a knee-length sleeve, the openings more preferably comprise between about 7% and about 10% of the total surface area of the respective inflatable bladder. In one example, openings in the distal bladder of a knee-length sleeve may comprise about 9.52% of the total surface area of the respective inflatable bladder; the openings in the intermediate bladder may comprise about 8.60%; and the openings in the proximal bladder may comprise about 7.77%. Each opening may comprise between about 0.5% and about 1.5% of the total surface area of the respective inflatable bladder. For example, each opening in the distal bladder may comprise about 1.20% of the total surface area of the respective inflatable bladder; each opening in the intermediate bladder may comprise about 0.96%; and each opening in the proximal bladder may comprise about 0.77%. In the illustrated embodiment, the total surface areas of the distal, intermediate and proximal bladders are 51.25 in 2  (330.64 cm 2 ), 63.84 in 2  (411.87 cm 2 ) and 78.48 in 2  (506.32 cm 2 ), respectively. For example, the sleeve can have at the distal bladder  8  openings; at the intermediate bladder  9  openings; and at the proximal bladder  10  openings. All of the openings have the same area of 0.61 in 2  (3.94 cm 2 ). 
     It is contemplated that the openings  32  may comprise a greater or lesser percent of the total surface area of the inflatable bladder than given above. However, there is a limit to the percent opening in an inflatable section. Experimentally total opening area above 10% is found to be uncomfortable to the patient, this relationship of opening size, the number of openings and their location is bounded by an upper and lower percent opening. In preferred embodiments of the present invention, the sleeve extends around the full circumference of the leg (or limb). However, the use of openings registered with wicking material can be included in other sleeves such as Huntleigh®, Hill-Rom® and Aircast® that have bladders that do not extend around the full circumference of the limb. 
     Opening location is important for comfort, use and blood flow. Recent internal studies at the Applicants demonstrated that blood flow for the current SCD Express models did not vary significantly when rotated about the wearer&#39;s leg. This further supports a symmetrical distribution of openings around and along the patient&#39;s limb for maintaining blood flow augmentation as was found in the testing shown in  FIG. 22 . 
     With respect to each bladder  24   a ,  24   b ,  24   c , the openings  32  are arranged in a distal row  36  and a proximal row  38  ( FIG. 4 ). Both rows  36 ,  38  extend across the respective bladder  24   a ,  24   b ,  24   c  along the width W of the sleeve  10 . As depicted in the drawings, the openings  32  in each proximal row  38  are inverted medium waterdrop-shaped openings in that the openings taper distally, while the openings in each distal row  36  are right-side-up in that the openings taper proximally. The openings  32  in each distal row  36  are offset along the width W of the sleeve from the openings in the respective proximal row  38 . Offsetting the openings  32  distributes the openings evenly across the surface area of the bladders  24   a ,  24   b ,  24   c , thereby increasing the breathability of the bladders and the overall breathability of the sleeve  10  without compromising the structural integrity of the bladders or their ability to apply compressive force (i.e., prophylaxis treatment) to the leg or body part. Moreover, offsetting the openings in the respective distal and proximal rows  36 ,  38 , also makes the bladders  34   a ,  34   b ,  34   c  more stretchable in the widthwise direction of the sleeve  10 . The above configuration allowed for one of the highest number of openings as found in Table II. In another embodiment described below the addition of peripheral openings  39  improved the effective or useable % Open area of a Sleeve as explained below. 
     Other ways of allowing fluid wicked by the inner layer  12  to evaporate, besides the openings  32  through the bladders are within the scope of the invention. For example, referring to  FIG. 14 , another embodiment of the sleeve is generally indicated at  10   a . The sleeve is similar to other embodiments in the present invention, and therefore corresponding parts have corresponding reference numerals. The difference between this sleeve  10   a  and the previous sleeve  10  is that in addition to the bladder openings  32 , peripheral openings  39  are formed through portions of the intermediate layers  14 ,  16  which do not define the bladders  24   a ,  24   b ,  24   c  (i.e., outside the peripheries of the bladder seam lines  22   a ,  22   b ,  22   c ). More specifically, the peripheral openings  39  are generally formed through portions of the inter mediate layers  14 ,  16  corresponding to side flaps  41   a ,  41   b , or  41   c  of the sleeve  10 . The peripheral openings  39  are generally waterdrop-shaped but are larger than the bladder openings  32 . Side flap  41   a  has three peripheral openings  39 , side flap  41   b  has two openings and side flap  41   c  has 1 opening. Like the bladder openings  32 , the peripheral openings  39  allow moisture wicked by the inner layer  12  to evaporate to the atmosphere. The peripheral openings  39  most commonly overlap or entirely overlie the sleeve  10  when the sleeve is wrapped circumferentially around the wearer&#39;s leg and secured to itself. In that situation, the portions of the inner layer  12  in registration with the peripheral openings  39  are not in direct contact with the wearer&#39;s leg. Moisture wicked by portion of the inner layer  12  in contact with the wearer&#39;s leg will move to the portions of the inner layer  12  in registration with the peripheral openings  39  because the openings allow evaporation of the wicked moisture (i.e., drying). Accordingly, the peripheral openings  39  provide more area for moisture to be evaporated from the inner layer  12 , which reduces the number and size of openings in the bladder area. 
     Referring to  FIG. 15 , in yet another example, the size and shape of the intermediate layers  14 ,  16  are such that the peripheries of the layers do not completely cover or overlie the inner layer  12 , whereby the inner layer  12  is exposed to the atmosphere. In the illustrated embodiment, the flaps  41   a ,  41   b ,  41   c  project laterally outward from lateral edges of the intermediate layers  14 ,  16 . Through this construction, large areas of the inner layer  12  foaming the flaps  41   a ,  41   b ,  41   c  are not covered by the intermediate layers  14 ,  16  and wicked fluid is allowed to evaporate through these areas. This embodiment functions in a similar manner as the embodiment illustrated in  FIG. 14 , in that it allows more moisture wicked by the inner layer  12  to be evaporated to the atmosphere. Other ways of allowing moisture wicked by the inner layer  12  to evaporate into the atmosphere are within the scope of the invention. The peripheral openings  39  allow for fewer openings at the inflatable section thereby improving blood flow to its theoretical maximum while maintaining the cooling affect for the patient. 
     With the addition of the peripheral openings  39  in the intermediate layers  14 ,  16  ( FIG. 14 ) and/or the portions of the inner layer  12  not overlaid by the intermediate layers ( FIG. 15 ), “a total open percentage” of the inner layer may be calculated, correlating to the total surface area of the inner layer not overlaid or covered by the intermediate layers  14 ,  16 . The total open percentage of the inner layer  12  is calculated by summing the surface areas of all portions of the inner layer that are not overlaid or covered by the intermediate layers  14 ,  16  and dividing this sum by the surface area of the inner layer. The surface area of the inner layer  14  is determined by the periphery dimensions of the inner layer, irrespective of any holes or openings in the layer. It is noted that the “total open percentage” of the inner layer  12  of the previous embodiment illustrated in  FIGS. 1-7  is equal to the total surface area occupied by the bladder openings  32  of all the bladders  24   a ,  24   b ,  24   c  divided by the total surface area of the bladders because the remainder of the intermediate layers  14 ,  16  completely overlies or covers the inner layer. However, in the present embodiments ( FIGS. 14 and 15 ), the total open percentage of the inner layer  12  is calculated by summing the surface areas occupied by the openings  32  in the bladders  24   a ,  24   b ,  24   c  (correlating to the total surface area of the inner layers in registration with the openings and therefore “open”) together with surface areas of any other portions of the inner layer that is not overlain or covered by the intermediate layers. In  FIG. 14 , the total open percentage of the inner layer  14  is equal to the sum of the areas of bladder openings  32  and the areas of the peripheral openings  39  divided by the surface area of the inner layer. 
     In  FIG. 15 , the total open percentage of the inner layer  14  is equal to the sum of the areas of bladder openings  32  and the surface areas of the other portions of the inner layer not covered by the intermediate layers  14 ,  16  divided by the surface area of the inner layer. In one example, the total open percentage of the inner layer  12  may be greater than about 10%, more specifically, between about 10% and about 20%, without patient discomfort when the openings are located at the sleeve itself. In another example, the total open percentage of the inner layer may be greater than 20%. Patient discomfort can result when the sleeve folds on itself or just does not stay snug or secure around a patient&#39;s limb. Therefore flaps are needed to hold the wrap onto the patient&#39;s body part. Prior art flaps would cover openings at the sleeve. By placing openings at the flaps as shown as peripheral openings  39 , the openings  39  are positioned to overlay the openings  32  and the total open percentage of the wicking material is maintained. Also, changing the opening  32  distribution not to coincide with the flaps is within the scope of this invention. Prior art devices such as U.S. Pat. No. 6,592,534 to Rutt show flaps  20  that wrap over the body of the foot cuff with no openings therethrough. Even Roth (U.S. Pat. No. 7,044,924) which has openings at the flaps for handles does not describe aligning the flap openings with the openings at seams of its sleeve. At  FIG. 2A  of Roth, the handles  222  are off the sleeve and over the loop material at the sleeve outer layer. 
     Referring to  FIGS. 18 and 19 , yet another embodiment of a compression sleeve is generally indicated at  100 . The flaps described provide an adjustable means to secure the wrap around the patient&#39;s limb. The flaps described are typically found in the prior art, such as U.S. Pat. No. 6,592,534 to Rutt, to be made of uniform, impermeable sheet with hook or loop material corresponding to loop or hook material at the outer cover. The difference is the flaps of the illustrated embodiment have an opening or cut out section from the flaps  102   a ,  102   b ,  102   c , which generally corresponds to the opening at the outer cover or bladder area of the sleeve. Thus, the open flap allows wicked moisture to evaporate to the atmosphere, as it is in registration with wicking material at the patent&#39;s skin. This will reduce the number of openings otherwise need to meet the evaporation rates needed to provide a cooler sleeve during use. 
     This embodiment is similar to the sleeve  10  illustrated in  FIGS. 1-7 , and therefore, like components are indicated by corresponding reference numerals. The difference between the present sleeve  100  and the sleeve  10  is that the present sleeve has bifurcated or split proximal and intermediate flaps  102   a ,  102   b , each being indicated generally in  FIGS. 18 and 19 . The amount of split or bifurcated distance “D” depends on the location and distribution of the openings  32 , so the opening distance “D” overlies the maximum number of openings  32 . Each of the proximal and intermediate flaps forms a pair of fingers  104   a ,  104   b  and  106   a ,  106   b , respectively, on which a fastening component  108 , such as a hook component, is secured. A peripheral opening  110  is formed through the intermediate layers  14 ,  16  at a distal, non-bifurcated flap  102   c  for purposes described above with respect to the embodiment illustrated in  FIG. 14 . The bifurcated flaps  102   a ,  102   b  make the sleeve  100  more adjustable when securing it circumferentially around a patient&#39;s leg to allow for different leg proportions among patients and to provide more comfort for the patient. It is understood that the flaps may be divided into more than two fingers and that different ones or all of the flaps may be bifurcated. 
     Referring to  FIGS. 16 and 17 , in another embodiment of the sleeve, generally indicated at  10   c , the inner layer  12 , the intermediate layers  14 ,  16  and the outer cover  18  are secured together along a single seam line  43 , which runs along the peripheries of the outer cover and the layers. In this embodiment, it has been found that the seam line  43  allows fluid wicked by the inner layer  12  to travel through the intermediate layers  14 ,  16  to the outer cover  18  and evaporate into the atmosphere. The outer cover  18 , the intermediate layers  14 ,  16  and the inner layer  12  are secured to one another in a single welding step, such as by a radiofrequency welder, after the layers have been stacked on one another. During this step, the intermediate layers  14 ,  16  are heated and softened along the seam line  43 . The softening of the intermediate layers  14 ,  16  is one way the fibers  43   a  ( FIG. 17 ) of the inner layer  12  extend entirely through the seam line to the exterior of the compression sleeve  10 . The fibers  43   a  are distributed uniformly throughout inner layer  12 . Thus, the inner layer  12  is able to wick fluid through the seam line  43  for evaporating into the atmosphere. The wicking layer  12  can be placed between layers  14 ,  16  at a spot weld. A seam line may be positioned along or around the compression device not just at the peripheral of a bladder. 
     Referring to  FIGS. 1 and 2 , the outer cover  18  of the compression sleeve  10  is constructed of a single sheet of material. The outer cover  18  is breathable and has a multiplicity of openings  40  or perforations so that it has a mesh construction to provide even more breathability. A suitable material for the outer cover  18  may be a polyester mesh. The rate of evaporation from the openings is improved by treating the fibers of the mesh material with a hydrophilic material. The mesh material will absorb the wicked fluid more readily. Wicking fibers of this type are indicated generally at  21  in  FIG. 7 . These hydrophilic fibers lower the surface tension of the mesh material to allow bodily fluids to more easily absorb into the fibers and spread therethrough for a more efficient evaporation of the wicked fluid. Absorbing fluid more readily will allow the fluid to move to the open areas more quickly for evaporation. The capillary effect is made more efficient as the absorbed fluid at the openings is moved more quickly through the mesh outer cover  18 . 
     Referring to  FIGS. 1 ,  5  and  6 , the outer cover  18  is secured to the second intermediate layer  16  along seam line  42 , which runs only adjacent to the outer periphery of the second intermediate layer so that the bladders  24   a ,  24   b ,  24   c  are free from attachment to the cover. The second intermediate layer  16  may be secured to the inner layer  12  by RF welding or adhesive or in other suitable ways. 
     Referring to  FIGS. 1 and 7 , the entirety of an outer surface of the outer cover  18  also acts as a fastening component of a fastening system for securing the sleeve  10  to the limb of the wearer. In a particular embodiment, the outer cover  18  of mesh ( FIG. 7 ), for example, has an outer surface comprising loops  44  ( FIG. 7 ), that acts as a loop component of a hook-and-loop fastening system. A mesh construction, as shown in  FIG. 7 , has interconnected or weaved fibers  21  of material forming the outer cover  18 . The loops  44  may be formed as part of the material of the outer cover  18  or otherwise disposed on the surface of the outer cover. A suitable material with such construction is a polyester mesh loop 2103 sold by Quanzhou Fulian Warp Knitting Industrial Co., Ltd. of Quanzhou City, China. Hook components  46  ( FIG. 3 ) are attached to an inner surface of the inner layer  12  at the proximal, intermediate and distal flaps  41   a ,  41   b ,  41   c , respectively. The loops  44  of the outer cover  18  allow the hook components  46  ( FIG. 3 ) to be secured anywhere along the outer surface of the outer cover when the sleeve  10  is wrapped circumferentially around the limb of the wearer. This allows for sleeve  10  to be of a substantially one-size-fits-all configuration with respect to the circumferences of different wearers&#39; limbs. Moreover, the outer cover  18  having the loops  44  allows the practitioner to quickly and confidently secure the sleeve  10  to the wearer&#39;s limb without needing to align the fastening components. 
     It is contemplated that the outer cover  18  may be capable of wicking fluid in addition to being breathable. For example, the outer cover  18  may be constructed of the same material as the inner layer  12  (e.g., Cool dry). In this way, the moisture wicked by the inner layer  12  may be wicked by the outer cover  18  through the openings  32  in the bladders  24   a ,  24   b ,  24   c . The moisture will then spread out evenly across the outer cover  18  and is able to evaporate more readily than if the outer cover was not formed of a wicking material because a greater surface area of the outer cover, as opposed to the inner layer  12 , is exposed to air. Alternatively, the cover can have a wicking material laced in or on top of outer layer. 
     Referring to  FIG. 13 , yet another embodiment of the sleeve is generally indicated at  80 . The difference between this sleeve and the first embodiment  10  is that the inner layer  12  and the outer cover  18  are secured to each other at seam lines  82  through the openings  32  in the bladders  24   a ,  24   b , and  24   c  to maintain the inner layer and outer cover in direct contact. In this embodiment, both the inner layer  12  and the outer cover  18  are constructed of suitable wicking material, such as CoolDry or CoolMax®. By being in constant contact, the outer cover  18  continuously wicks moisture from the inner layer  12  through the openings  32  in the bladders  24   a ,  24   b ,  24   c . As explained above, in this way a larger surface area having wicked moisture is exposed to air and the wicked moisture can evaporate more quickly. 
     The compression sleeve  10  as a whole is more comfortable to wear because of the synergistic relationship of the layers  12 ,  14 ,  16 ,  18 . For example, the inner layer  12  is capable of wicking moisture from the limb and allowing the moisture to evaporate out of the sleeve  10 . As stated above, wicking involves transporting moisture away from the limb and moving moisture from locations where it is abundant and transporting it to areas where it is less abundant. Material decreases its wicking rate when the moisture is equally distributed in the wicking material and the wicking material is saturated. However, the breathability of the sleeve  10  allows for the wicked moisture to evaporate. The waterdrop-shaped openings  32  in the bladders  24   a ,  24   b ,  24   c  and the breathable outer cover  18  allow moisture in the inner layer  12  that is adjacent to the openings to evaporate therethrough. Accordingly, as the moisture evaporates, it is transported to the drier portions of the inner layer  12 , and the inner layer is able to wick more moisture. Testing described below supports the findings of breathable outer cover improves the cooling affect to the patient. If one places the openings  32  at the corner points of a generally square pattern, then the middle of the square is theoretically the farthest distance trapped moisture must be wicked in terms of distance to an opening. The closer the openings are together the more rapidly the wicked moisture is evaporated because the distance to an opening is shortened. The further apart the openings, the greater the distance the wicked moisture must travel and the less comfort the device provides to the patient, in terms of cooling. The testing described below helped determine the optimum spacing and size to provide cooling without compromising blood flow as shown in  FIG. 22 . 
     Summarized in Table III are the evaporation test results of an embodiment constructed according to the principles of the present invention having the waterdrop-shaped opening as compared with competitor sleeves A and C. 
     
       
         
           
               
             
               
                 TABLE III 
               
             
            
               
                   
               
               
                 Evaporation Rates by Sleeve 
               
            
           
           
               
               
               
               
               
            
               
                   
                 Present 
                 Prior 
                   
                   
               
               
                   
                 Invention 
                 Art SCD 
                   
                   
               
               
                   
                 Waterdrop- 
                 Express 
                   
                   
               
               
                   
                 shape 
                 9529 
                 Sleeve A 
                 Sleeve C 
               
               
                   
               
            
           
           
               
               
               
               
               
            
               
                 Entire Sleeve Area 
                 280 
                 264 
                 210 
                 198 
               
               
                 (in 2 ) 
                   
                   
                   
                   
               
               
                 Available Bladder 
                 173 
                 178 
                 55 
                 58 
               
               
                 Area(in 2 ) 
                   
                   
                   
                   
               
               
                 % of Bladder Area 
                 61.8% 
                 67.4% 
                 26.2% 
                 29.3% 
               
               
                 % of Open Area 
                 5.9% 
                 0.0% 
                 0.0% 
                 0.0% 
               
               
                 through Bladder of 
                   
                   
                   
                   
               
               
                 Entire Sleeve 
                   
                   
                   
                   
               
               
                 Average Evaporation 
                 0.03268 
                 0.00598 
                 0.0424 
                 0.03488 
               
               
                 Rate (g/min) 
                   
                   
                   
                   
               
               
                 Average Evaporation 
                 0.00012 
                 0.00002 
                 0.00020 
                 0.00018 
               
               
                 Rate per in 2  of Entire 
                   
                   
                   
                   
               
               
                 Sleeve (g/min/in 2 ) 
                   
                   
                   
                   
               
               
                 Average Evaporation 
                 0.02019 
                 0.00403 
                 0.01110 
                 0.01022 
               
               
                 Rate Vs. Bladder 
                   
                   
                   
                   
               
               
                 Coverage (g/min) 
               
               
                   
               
            
           
         
       
     
     For purposes of this application, the following test (referred to herein as the “static evaporation test”) is used to determine the rate of evaporation of moisture wicked by the wicking layer through sleeve (e.g., through the openings, at the seam lines and/or the other portions of the bladder layers not overlying the wicking layer). The results are summarized in Table III. A polycarbonate plate is placed on a digital scale. The polycarbonate plate has a peripheral shape matching the peripheral shape of the sleeve to be tested, so that the sleeve may be superposed on the plate. The digital scale has a 2000 grain capacity with a 0.01 gram resolution. After the plate is placed on the scale, the scale is zeroed. Next, a mixture of room temperature tap water and food coloring (e.g., red food coloring) is sprayed onto the polycarbonate plate using a spray bottle. About 18 to 20 grams of the mixture is sprayed generally uniformly across the surface area of the plate. The sleeve to be tested is then placed on the plate so that the sleeve is generally flat on the plate and generally superposed thereon. The mass reading on the scale is recorded, along with the room temperature and the relative humidity. Every 30 minutes for at least 5 hours, the mass reading on the scale, the room temperature and the relative humidity are recorded. After completion of the test, with the sleeve still on the plate, a photograph of the underside of plate is taken to capture the distribution of any remaining fluid on the plate and the sleeve. Finally, using the recorded data, the evaporation rate and percentage of fluid evaporated by mass (e.g., mg/minute) for each sleeve is calculated. 
     Using the above-described static evaporation test, a sleeve of the type illustrated in  FIG. 20  was tested. The same testing procedure can be applied to the other embodiments, such as the full length sleeve of  FIG. 1 . It was shown that moisture wicked by the inner layer of the sleeve was able to evaporate through each opening of the sleeve at a rate of between about 0.5 mg/minute and about 2.0 mg/minute and more specifically, between about 1.1 mg/minute and about 1.5 mg/minute. The overall rate of evaporation through all of the openings was between about 20 mg/minute and about 50 mg/minute and more specifically, between about 30 mg/minute and about 40 mg/minute. As explained above, in general the static evaporation test showed that increasing the percentage of the openings with respect to individual bladders increased the evaporation rate of the sleeve. The increase in evaporation rate did not increase proportionally above 30% total open percentage of the inner layer  12 . It is also contemplated that using an inner layer that is capable of wicking fluid at a faster rate may also increase the evaporation rate of the sleeve. Other ways of increasing the evaporation rate of the sleeve are within the scope of the present invention. 
     The overall breathability of the sleeve  10  also aids in keeping the sleeve comfortable for the wearer. Because the inner layer  12 , the bladders  24   a ,  24   b ,  24   c  and the outer cover  18  are breathable, the limb has access to air and heat is allowed to dissipate out of sleeve. The waterdrop-shaped openings  32 , through their number and location along and around the sleeve, allow a significant amount of air to reach the limb and a significant amount of heat and moisture therein to be removed from the sleeve. This has the effect of keeping the limb cool and comfortable for the wearer. 
     The calculation of evaporation results, as found in Table III above is determined by the following equations:
 
% of liquid evaporated, LEi =(( Wsn−Wso )−( Wsn− 1 −Wso ))/( Wsn−Wso ),
 
     Where LEi is the incremental % of liquid evaporated at a given data point; 
     Where Wsn is the weight of the sample at the desired data point; 
     Where Wsn−1 is the weight of the sample at the previous data point; 
     Where Wso is the original dry weight.
 
% of liquid evaporated, LEc =[(( Wsn−Wso )−( Wsn− 1− Wso ))/( Wsn−Wso )]+Σ nLEi,  
 
     Where ERc is the cumulative % of liquid evaporated; 
     Where Wsn is the weight of the sample at the desired data point; 
     Where Wsn−1 is the weight of the sample at the previous data point; 
     Where Wso is the original dry weight; 
     Where ΣnLEi is the summation of the previous incremental % of liquid evaporated.
 
Evaporation Rate, ER =( Wsn− 1− Ws )/Δ t,  
 
     Where Wsn−1 is the weight of the sample at the previous data point; 
     Where Ws is the current weight of the sample; 
     Where Δt is the change in time between Wsn−1 and Ws. 
     To improve patient mobility, the sleeve was designed to have an elastic inner layer  12  and outer cover  18 . An elastic sleeve improves comfort which increases patient compliance. Refer to  FIGS. 1-7  for the discussion on elasticity below. An elastic device will conform to a patient&#39;s limb to ensure continuous wicking. A compliant or substantially conforming fit will help ensure the contact of the bladder against a patient&#39;s skin during use. The bladder applies the pressure to move the blood. The elastic outer layer helps reduce number of straps to hold the sleeve in place because the elastic outer layer  18  returns its original shape exerting a slight force against the patient&#39;s limb. This force helps hold the sleeve in place and also allows the practitioner not to over tighten a strap. Some prior art devices use an elastic stocking, such as the T.E.D.® stocking, beneath the compression sleeve. The compression sleeve of at least some embodiments avoids the two step process of first placing the compression stocking on the patient, then placing the sleeve over the stocking. Also sleeves of preferred embodiments of the present invention simplify the job of the nurses because there is no need to order a stocking and sleeve. 
     The Applicant devised an elasticity test for determining the amount of stretch around the limb and along the limb. A patient needs to be mobile during treatment. Prior art sleeves can be awkward, stiff and heavy so the user would remove the device, if they needed to move about. The need is to improve elasticity without distorting the openings  32  too much such as becoming elongated or causing an opening to overlie, which reduces its size for evaporation. 
     For example, the inner layer  12  is preferably elastically stretchable along the width W of the sleeve  10  so that the inner layer is able to conform circumferentially to the shape of the wearer&#39;s limb. Conforming circumferentially allows the inner layer  12  to remain in close, intimate and continuous contact with the wearer&#39;s limb to ensure that the inner layer is continuously wicking moisture from the limb. The inner layer  12  may also be stretchable the length L. Preferably, the inner layer  12  is elastically stretchable along both the width W and the length L of the sleeve and is more elastically stretchable along the length of the sleeve  10  than along the width. Summarizing the preferred approach, using the test described below, the inner layer  12  may have an average elasticity in the widthwise direction of the sleeve of between about 13 lbs/in (23 N/cm) and about 14 lbs/in (25 N/cm), and in one embodiment has an elasticity of about 13.3 lbs/in (23.3 N/cm). The inner layer  12  may have an average elasticity in the lengthwise direction of the sleeve of between about 0.5 lbs/in (0.9 N/cm) and about 0.7 lbs/in (1.2 N/cm), and in one embodiment has an elasticity of about 0.63 lbs/in (1.10 N/cm). The small openings  20  in the inner layer  12  also allow for the inner layer stretch more. 
     The outer cover  18  is also elastically stretchable along the length L of the sleeve  10  or stretchable along both lengthwise and widthwise (circumferentially). Preferably, the outer cover  18  is more elastic longitudinally than widthwise. Although elastically stretchable, the outer cover  18  acts to restrain the amount of expansion of the bladders  24   a ,  24   b ,  24   c . The outer cover  18  helps to conform the bladder to the limb for helping to evenly apply pressure for moving blood. For example, using the elasticity test described below, the outer cover  18  may have an average elasticity in the widthwise direction of between about 13 lbs/in (23 N/cm) and about 15 lbs/in (26 N/cm), and in one embodiment has an elasticity of about 13.6 lbs/in (23.8 N/cm). The outer cover  18  may have an average elasticity in the longitudinally direction of between about 19 lbs/in (33 N/cm) and about 22 lbs/in (39 N/cm), and in one embodiment an elasticity of about 19.8 lbs/in (34.7 N/cm). 
     The compression sleeve  10  as a whole is stretchable longitudinally by way of the longitudinally stretchable inner layer  12 , intermediate layers  14 ,  16  and outer cover  18 . Further, the sleeve  10  is slightly stretchable widthwise by way of the abilities of the inner layer  12 , intermediate layers  14 ,  16  and the cover  18  to stretch widthwise. The waterdrop-shaped openings  32  and the fact that the openings are offset widthwise also aid in the widthwise stretching. 
     It is common for patients that have undergone surgery to incur swelling of the limbs. The widthwise stretching of the sleeve  10  is more comfortable for patients that experience swelling because the sleeve will stretch, i.e., increase in size circumferentially, as the limb swells. Moreover, elasticity of the sleeve  10  allows the wearer to have more mobility of his or her limb and gives the practitioner a greater degree of freedom when wrapping the sleeve around a wearer&#39;s leg. For example, using the elasticity test described below, the thigh-length sleeve  10 , comprising the inner layer  12 , the intermediate layers  14 ,  16  and the outer cover  18  as described above, may have an average elasticity in the widthwise direction of between about 22 lbs/in (39 N/cm) and about 27 lbs/in (47 N/cm), and in one embodiment an elasticity of about 24.3 lbs/in (42.6 N/cm). The compression sleeve  10  may have an average elasticity in the lengthwise direction of between about 17 lbs/in (30 N/cm) and about 22 lbs/in (39 N/cm), and in one embodiment an elasticity of about 19.4 lbs/in (34.0 N/cm). 
     In another example, using the elasticity test described below, a knee-length sleeve, comprising an inner layer, intermediate layers and outer cover of the same material as the thigh-length sleeve described above, may have an average elasticity in the widthwise direction of between about 22 lbs/in (39 N/cm) and about 27 lbs/in (47 N/cm), and an average elasticity in the lengthwise direction of between about 33 lbs/in (58 N/cm) and about 40 lbs/in (70 N/cm). 
     The following test (herein referred to as the “elasticity test”) is used to measure the elasticity of the layers  12 ,  14 ,  16  and  18  and the sleeve  10 , both widthwise and lengthwise. First, structure clamps are secured to the structure (e.g., one of the layers  12 ,  14 ,  16 , and  18  or the sleeve  10 ) to be tested. When testing the lengthwise elasticity, the structure clamps are secured to top and bottom edges of the structure. When testing the widthwise elasticity, the structure clamps are secured to opposite side edges of the structure. The sleeve sample with the structure clamps secured thereto is placed in a universal tensile testing machine (such as a universal testing machine manufactured by Instron® of Grove City, Pa.) by securing the structure clamps to opposing machine clamps of the machine. The machine should include a microprocessor having a tensile force measurement program used to control the machine and record measurements of force and displacement. Once the structure is secured in the machine, the opposing machine clamps are moved apart to a position that eliminates or minimizes the slack in the structure. This position is the initial position for all subsequent tests. The tensile force measurement program is then executed. The displacement of the sleeve sample as the machine clamps are moved apart should be uniform linear elongation and should not damage the structure. This displacement is set and maintained for each test repetition. The test is repeated 7 times for each layer  12 ,  14 ,  16  and  18  and the sleeve  10 . Elasticity is calculated as force (lbs) divided by the displacement (in). An average elasticity of the 8 tests is calculated by summing the elasticity calculations for the 8 tests and dividing the sum by 8. 
     The sleeve in some embodiments is made more comfortable for the wearer by the fact that the inner layer  12  and the outer cover  18  are secured to the respective intermediate layers  14 ,  16  only adjacent to the outer peripheries of the inner layer and cover whereby the bladders  24   a ,  24   b ,  24   c  are not secure directly to the inner layer and cover. This construction allows for the bladders  24   a ,  24   b , and  24   c  to move independently of the inner layer  12 , and vice versa. Co-assigned U.S. patent application Ser. No. 11/299,568 disclosing an embodiment directed to reducing chafing of a person&#39;s skin during use is incorporated herein by reference. 
     Thus, when the sleeve  10  is wrapped circumferentially around the wearer&#39;s limb, the inner layer  12  substantially conforms to the contour or shape of the limb and will remain substantially stationary against the wearer&#39;s limb as the bladders  24   a ,  24   b ,  24   c  inflate and deflate and/or shift positions. The movement of the bladders  24   a ,  24   b ,  24   c  both as they inflate and deflate and shift positions relative to the limb may cause chaffing and other discomfort for the patient if the surface of the bladders continuously rubbed against the limb. However, by being secured only at the outer peripheries of the intermediate layers  14 ,  16 , the inner layer  12  creates a buffer between the bladders  24   a ,  24   b ,  24   c  and the limb that prevents chaffing and other friction against the skin of the limb. The bladders  24   a ,  24   b ,  24   c  may move without causing corresponding movement of the inner layer  12  against the skin. 
     Referring now to  FIGS. 8 and 9 , another embodiment of the sleeve is generally indicated at  50 . This embodiment  50  is similar to the first embodiment  10 , and therefore, corresponding parts will be indicated by corresponding reference numbers. The difference between the present embodiment  50  and the first embodiment  10  discussed above is that each of the intermediate layers  14 ,  16  comprises three separate sheets  52   a ,  54   a ,  56   a  and  52   b ,  54   b ,  56   b , respectively. Corresponding intermediate sheets  52   a ,  52   b  and  54   a ,  54   b  and  56   a ,  56   b , are secured together to form the three separate bladders  24   a ,  24   b ,  24   c  ( FIG. 9 ). The remainder of the sleeve  50  is constructed similar to the first embodiment, including the intermediate sheets  52   a ,  54   a ,  56   a  and  52   b ,  54   b ,  56   b  being secured only adjacent to the respective peripheries of the outer cover  18  and the inner layer  12  so that the central portions of the bladders  24   a ,  24   b ,  24   c  are free from securement to the inner layer and outer cover. It is also contemplated that adjacent bladders  24   a ,  24   b ,  24   c  may be connected to each other by elastically stretchable material other than the inner layer  12 . 
     In addition to the advantages given above with respect to the first embodiment  10  of the compression sleeve, the present embodiment  50  also allows for better fit to a given individual&#39;s leg because the ability of the sleeve to stretch longitudinally is dependent only on the stretchabilities of the inner layer  12  and cover  18 . In one embodiment, the inner layer  12  and the outer cover  18  are more stretchable than the intermediate layers  14 ,  16 , and in particular, more stretchable longitudinally than the inner layer and the outer cover. Thus, the sleeve  50  may stretch between the proximal and intermediate bladders  24   a ,  24   b  without shifting the locations of the bladders on the leg (i.e., the bladders remain in place). In one example, at least one of the inner layer  12  and outer cover  18  is not resilient so that the sleeve  50  retains its stretched form after stretching. In another example, at least one of the inner layer  12  and outer cover  18  is resilient so that the sleeve  50  returns to its original form after a stretching force is released. The ability of the sleeve  50  to elastically stretch allows for the practitioner to readily adjust the positions of the bladders with respect to the wearer&#39;s limb. It is also contemplated that another stretchable component or material, other than the inner layer and the outer cover, may connect adjacent bladders. 
     Referring to  FIGS. 10-12 , yet another embodiment of a compression sleeve is generally indicated at  60 . Sleeve  60  is similar to the first embodiment, and therefore, like parts are indicated by corresponding reference numerals. The difference between this sleeve  60  and the first embodiment  10  is that inflatable bladders, generally indicated at S 1 , S 2 , S 3  ( FIG. 11 ), are generally S-shaped and do not include openings formed therethrough. 
     Each S-shaped bladder S 1 , S 2 , S 3  is formed by securing the two intermediate layers  14 ,  16  together along an S-shape seam line  64 . The S-shaped bladders S 1 , S 2 , S 3  each include spaced apart proximal, intermediate and distal (or “first, second, and third”) sections  66 ,  68 ,  70 , respectively, along the length L of the sleeve  60 . The general shapes of the bladders S 1 , S 2 , S 3  are indicated by a centerline in  FIG. 10 . Holes  72  are formed through the intermediate layers  14 ,  16  between the proximal and intermediate portions  66 ,  68 , respectively, of the bladders S 1 , S 2 , S 3  and the intermediate portion and distal portion  70  of the bladders. Referring to  FIG. 12 , instead of numerous openings  72 , continuous slits  74  may extend along the width of the sleeve  60  substantially the entirety of the length of the space between disposed between the proximal and intermediate portions  66 ,  68  and intermediate portion and distal portion  70  of each bladder S 1 , S 2 , S 3 . The openings/slits  72 ,  74  may be other shapes and sizes. Additional opening(s) may also be formed through the intermediate layers  14 ,  16  between the individual bladders S 1 , S 2 , S 3  to make the sleeve  60  more breathable. For example, in the illustrated embodiment, an opening  75  is located between the bladders S 2  and S 3 . Moreover, it is understood that the S-shaped bladders may include the openings (e.g., like openings  32 ) through the bladders S 1 , S 2 , S 3  as shown in the first embodiment without departing from the scope of the invention. Alternatively, as with the sleeve  50  embodied in  FIGS. 8 and 9 , the bladders S 1 , S 2 , S 3  may be formed separately from separate intermediate sheets and may be spaced apart longitudinally along the sleeve  60 . The remainder of the sleeve  60  may be constructed in the same manner as described above with respect to the first and second embodiments. 
     The present sleeve  60  allows for large openings  72 ,  74 ,  75  to be formed through the intermediate layers  14 ,  16 , thereby making the sleeve more breathable and allowing for more moisture to dissipate through the sleeve, without forming openings through the bladders S 1 , S 2 , S 3 . Openings  72 ,  74  in the sleeve  60  are spaced at smaller intervals along the length L of the sleeve without forming holes through the bladders S 1 , S 2 , S 3  than if the bladders were not S-shaped. 
     In another embodiment shown in  FIG. 14 , the distal and intermediate bladders  24   c ,  24   b , respectively, share a portion of their seam lines  22   c ,  22   b , respectively. This portion of seam lines  22   c ,  22   b  is generally wavy so that portions of the intermediate bladder  24   b  are distal of adjacent portions of the distal bladder  24   c , and correspondingly, portions of the distal bladder are proximal of adjacent portions of the intermediate bladder. 
     As is known in the art, the bladders  24   a ,  24   b ,  24   c  are pressurized to different pressures. For example, the distal bladder  24   c  is pressurized to a higher pressure than the intermediate bladder  24   b . The wavy portion of the seam lines  22   c ,  22   b  creates a transition section defined by the wavy portion having a pressure that is between the high pressure of the distal bladder  24   c  and the lower pressure of the intermediate bladder  24   b . The wavy transition section, in effect, avoids a region of essentially zero pressure and helps prevent pooling of blood between the adjacent bladders  24   b ,  24   c . Industry studies performed by Nicolaides, Olson and Best all describe the importance of preventing the pooling of blood that can lead to venous stasis—a condition having a high occurrence of leading to a pulmonary embolism. 
     Referring now to  FIG. 20 , another embodiment of a compression sleeve is generally indicated at  200 . This sleeve is a knee-length sleeve. The sleeve  200  is similar to the sleeve illustrated in  FIGS. 1-7 , and like parts are indicated by corresponding reference numerals plus  200 . The sleeve  200  includes a wicking, breathable inner layer  212 , intermediate layers  214 ,  216  defining three bladders  224   a ,  224   b ,  224   c , and a breathable outer cover  218 . Openings  232  are formed in each of the bladders  224   a ,  224   b ,  224   c  to allow moisture (e.g., moisture) wicked by the inner layer  212  to evaporate through the intermediate layers  214 ,  216  and the outer cover  218 . The difference between the present sleeve  200  and the sleeve  10  illustrated in  FIGS. 1-7  is that the present sleeve is sized and shaped to be received around the lower portion of the leg below the knee. Thus, the sleeve  200  does not have bridge members or a knee opening. Instead, the three bladders  224   a ,  224   b ,  224   c  are conjoined. It is understood that the sleeve  200  may have other configurations and/or characteristics, such as those described above in reference to other embodiments, without departing from the scope of the present invention. 
     When introducing elements of the present invention or the preferred embodiments(s) thereof, the articles “a”, “an”, “the” and “said” are intended to mean that there are one or more of the elements. The terms “comprising”, “including” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements. 
     In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained. 
     As various changes could be made in the above constructions, products, and methods without departing from the scope of the invention, it is intended that all matter contained in the above description and shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.