Patent Document

This application is a continuation of Ser. No. 08/965,306 filed Nov. 6, 1997, now U.S. Pat. No. 5,964,792, which also is a continuation of Ser. No. 08/691,593 filed Aug. 2, 1996, now U.S. Pat. No. 5,733,318, which also is a continuation of Ser. No. 08/315,960 filed Sep. 30, 1994, now U.S. Pat. No. 5,545,194. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates generally to thermal blankets and, more particularly, to thermal blankets that deliver a bath of a thermally-controlled medium to a body. 
     2. Description of the Related Art 
     It often is necessary to bathe a patient in a thermally-controlled medium for the purpose of controlling the patient&#39;s body temperature. For example, it is important to keep a patient warm during surgery and to warm the patient post-operatively to reduce the risk of hypothermia. Typically, a patient&#39;s body temperature is controlled during surgery by using operating room blankets that cover the parts of a patient&#39;s body not being operated upon. Multiple blankets are overlaid, or variously shaped blankets having cut-outs or flaps are used, to cover most of the patient and still provide access to target surgical sites. After surgery, the patient is covered with a full-body blanket that covers all of the patient except for the head. Thus, as much of the patient as possible is kept covered during surgery to keep the patient warm while providing access to the operating site and after surgery a full body blanket keeps the patient warm. 
     It is known to provide an inflatable covering into which a thermally-controlled inflating medium is introduced. For warming purposes, the inflating medium can be warmed air. The thermally controlled medium also can be cooled air. When such a covering is inflated, it self-erects about a patient to produce a structure having a thermally-controlled interior environment. See, for example, U.S. Pat. Nos. 4,572,188 and 5,324,320, commonly assigned with this application and incorporated herein by this reference. 
     The prior art inflatable covering is an inflatable blanket that includes an array of apertures on its underside. The thermally-controlled medium is exhausted from the apertures into the erected structure and bathes the patient in the inflating medium. The temperature of the environment provided by the inflated blanket is determined by the temperature of the inflating medium. Thus, relatively uniform and precise control over the ambient environment of the patient can be achieved. Such thermal blankets are advantageously used to warm or cool patients before, during, and after surgery. 
     To expose an operating site during surgery or otherwise permit access to part of a patient&#39;s body while using an inflatable thermal blanket, a patient is covered with the blanket and a blanket area around the site of interest is sealed to provide a boundary against deflation. The blanket within the sealed area can be cut out, creating an open space in the blanket for access to the site of interest, while maintaining the inflatable integrity of the blanket. The blanket can then be inflated with the thermally-controlled medium to completely cover the patient except for the site of interest and thereby control the patient&#39;s temperature during surgery. After surgery, the inflatable blanket can be removed and replaced with a full-body blanket or a supplemental blanket can be draped across the exposed site. See, for example, U.S. patent application Ser. No. 07/638,748, commonly assigned with this application and incorporated herein by this reference. 
     It would be advantageous if it were not necessary to change blankets or add blankets between surgery or other medical procedures and the recovery period. This would permit a single blanket to be used for each patient, rather than multiple blankets. A single blanket would make it unnecessary to layer multiple blankets or to cut or shape blankets to provide surgical access to parts of a patient&#39;s body. The cost of maintaining an inventory of blankets and the time spent changing or modifying blankets also could be saved. 
     From the discussion above, it should be apparent that there is a need for a thermal blanket that can be used to cover a patient during surgery or other medical procedures in which it is necessary to gain access to a portion of the patient&#39;s body and that also can be used after the medical procedure is completed to fully cover the patient and provide a thermally-controlled environment. The present invention satisfies this need. 
     SUMMARY OF THE INVENTION 
     In accordance with the invention, an inflatable, self-erecting thermal blanket includes one or more portions that are gathered in a non-inflated condition and held thereby a closure such that a thermally-controlled inflating medium that is admitted into the blanket is prevented from being admitted into the gathered portion(s), thereby inflating a primary part of the blanket, which can be used to cover a patient, and leaving a void in the area covered by the blanket so as to expose an area of the patient&#39;s body for medical treatment. After the medical treatment, the closure can be released, thereby permitting the inflating medium to be admitted into the gathered portion such that the gathered portion inflates and covers the exposed area of the patient&#39;s body. The released thermal blanket then covers the entire patient and bathes the patient in the inflating medium. In his way, a single thermal blanket can be used to provide a thermally controlled environment and expose an area of a patient during treatment and also can be converted to fully cover the patient after treatment. 
     In one aspect of the invention, the gathered portion of the thermal blanket is created by rolling or folding an extension of the blanket onto itself and is maintained in the gathered condition adjacent the primary portion of he blanket by a closure comprising an elongated strip of tape that bridges both the gathered portion and the primary portion. The strip is provided with a release element that permits the gathered portion of the strip to be separated from the primary portion of the strip. When a patient is to be filly covered, the release element releases the gathered portion, which is then inflated by the inflating medium and covers a previously exposed area of the patient. 
     The closure and the release element can be provided by a variety of structures. For example, in one aspect of the invention, the closure comprises a strip that includes two longitudinal edges, one of which is attached to the gathered portion and the other of which is attached to the primary portion of the thermal blanket. The strip can include a central perforation that can be split open such that the gathered portion edge of the strip can be separated from the primary portion edge of the strip, releasing the gathered portion of the thermal blanket and permitting it to be unfurled and inflated. Alternatively, the release element can comprise a tear string embedded in a strip that bridges the gathered portion and primary portion. When the patient is to be fully covered, the tear string can be pulled out of the strip to separate the two edges of the strip and release the gathered portion. In another aspect of the invention, the release element can comprise a releasable hook and loop system having a hook strip attached to either the gathered portion or the primary portion and a loop strip attached to the other portion. The hook strip can be easily separated from the loop strip. A variety of other closures and release elements will occur to those skilled in the art. 
     Other features and advantages of the present invention should be apparent from the following description of the preferred embodiments, which illustrate, by way of example, the principles of the invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a view of an inflatable thermal blanket constructed in accordance with the present invention to initially cover a patient&#39;s lower body, having a gathered portion of the blanket in a non-inflated condition to permit access to the patient&#39;s upper body during medical treatment. 
     FIG. 2 is a view of the blanket illustrated in FIG. 1 after the gathered portion has been released and the patient fully covered. 
     FIG.  3  and FIG. 4 are views illustrating construction details of the blanket illustrated in FIGS. 1 and 2. 
     FIG. 5 is an exploded view of the blanket illustrated in FIG. 1 showing the closure before attachment to the blanket. 
     FIG.  6  and FIG. 7 are views of an inflatable thermal blanket constructed in accordance with the present invention to provide access to a patient&#39;s lower body during medical treatment. 
     FIG.  8  and FIG. 9 are views of another inflatable thermal blanket constructed in accordance with the present invention to provide access to a patient&#39;s lower body during medical treatment. 
     FIG. 10, FIG. 11, and FIG. 12 are views of a third inflatable thermal blanket constructed in accordance with the present invention to provide access to a patient&#39;s lower body during medical treatment. 
     FIG.  13  and FIG. 14 are views of an inflatable thermal blanket constructed in accordance with the present invention to provide access to a patient&#39;s upper body during medical treatment. 
     FIG.  15  and FIG. 16 are views of an inflatable thermal blanket constructed in accordance with the present invention having alternative closures to those illustrated in FIGS.  1 - 14 . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1 shows an inflatable thermal blanket  10  constructed in accordance with the present invention. As shown, the blanket provides access to the upper body of a patient  12  during medical treatment and includes a lower end  14  that is placed near the feet of the patient and an upper end rolled onto itself to form a gathered portion  16  and a primary portion  17 . Thus, the torso of the patient  12  is not covered by the blanket in the gathered condition. An inlet port  18  of the blanket is connected by a hose  19  to a heater/blower assembly  20  that produces a thermally controlled inflating medium, such as heat and air. When the blanket  10  is inflated with the heater/blower assembly, the blanket erects itself into a structure having a quilted upper surface  22 . Medical treatment can then be provided to the exposed torso of the patient while the remainder of the patient&#39;s body is kept warm by the blanket. A closure  24  maintains the gathered portion  16  in a non-inflated condition. After the medical treatment has been completed, the closure is opened so as to release the gathered portion, permitting the inflating medium to enter the gathered portion, inflating it so that it assumes the configuration illustrated in FIG.  2 . In this way, the same blanket can be used to keep an area of the patient&#39;s body warm during medical treatment and then can be converted into a full body covering after completion of treatment. 
     FIG.  3  and FIG. 4 illustrate some of the construction details of the thermal blanket  10 . A lower sheet  49  of the blanket is formed by bonding a layer  50  of flexible material to a layer  52  of heat-sealable plastic. In the preferred embodiment, the layers  50  and  52  respectively comprise a layer of non-woven polyester pre-laminated with a layer of heat sealable plastic such as a polypropylene extrusion. An upper layer  53  of the thermal blanket consists of a layer of extruded polypropylene film bonded to the plastic underside layer  52  by a heat-sealing process to form interrupted seams, one of which is indicated by the arrow  54 , and inflatable tubes, one of which is indicated by the arrow  55 . As can be seen in FIG. 4, the seam  54  forms a passageway  56  between two adjacent tubes  55  and  57 . 
     The thermal blanket  10  bathes a patient in the thermally controlled inflating medium by means of a plurality of apertures  62  illustrated in FIG.  4 . The apertures extend through the blanket underside, which includes the layers  50  and  52 . The apertures  62  are provided in a pattern determined to produce a uniform flow of the inflating medium from the underside of the blanket. For example, the apertures are provided in a density that varies inversely with the distance of the aperture to the center tube having the inlet port  18 . Thus, the ambient temperature beneath the inflated blanket is substantially uniform from edge to edge. 
     FIG. 5 illustrates the manner of attaching the closure  24  to the blanket in the gathered position. As illustrated in FIG. 5, the closure comprises an elongated strip having a first edge  26  that is attached to the primary portion  17  of the thermal blanket and a second edge  28  attached to the gathered portion  16  of the blanket. In FIG. 5, the closure  24  is shown in phantom, and therefore a strip of adhesive backing  30  applied along the underside of the first edge is indicated by shading, as is another strip of adhesive backing  32  applied along the underside of the second edge. Thus, the elongated strip of the closure  24  bridges the primary portion  17  and the gathered portion  16 , thereby holding the gathered portion  16  in the rolled, non-inflated condition. In this way, when the inflating medium is admitted into the thermal blanket to inflate the primary portion  17  through the inlet  18 , the gathered portion does not inflate. 
     FIG. 5 also shows that a central tear strip  34  is defined between the first edge  26  and second edge  28  of the closure  24  by two parallel perforations  36 ,  38  that extend along the length of the closure strip. It should be apparent that one end  40  of the tear strip can be grasped and pulled, tearing the perforations apart, thereby releasing the first edge from the second edge, permitting the gathered portion to be unfurled, and permitting the inflating medium to be admitted into the gathered portion to inflate the blanket and assume the condition illustrated in FIG.  2 . 
     The FIG. 5 embodiment shows that the closure  24  also can include an attachment flap  70  that extends outwardly from the second edge  28  of the closure. A free edge  72  of the attachment flap is provided with a strip of adhesive  74  on its underside along its length. The adhesive is used to attach the flap to the patient&#39;s body, thereby holding the gathered portion  16  in a fixed relative location. Holding the gathered portion fixed assists the attending medical personnel in maintaining the thermal blanket  10  in a desired location while medical treatment is provided. The attachment flap  70  preferably also includes a perforation  76  that can be torn, thereby releasing the closure  24  (and also the gathered portion  16 ) from the attachment flap. Thus, the attachment flap can be released independently of, or along with, the elongated strip of the closure  24 . 
     A thermal blanket in accordance with the present invention can be provided in a variety of configurations in addition to that illustrated in FIGS. 1 and 2. For example, FIG.  6  and FIG. 7 illustrate a thermal blanket  100  that provides access to the lower extremities of the patient  12  while covering the torso of the patient during treatment. In FIG.  6  and the remaining drawings, the heater/blower assembly  20  and connected hose  19  are not shown for clarity of illustration, but it should be understood that these elements are included in any actual usage of the thermal blanket. FIG. 6 illustrates the blanket  100  in the gathered condition and FIG. 7 illustrates the blanket in the fully deployed condition. Again, a gathered portion  116  and a primary portion  117  are provided by rolling one end of the thermal blanket onto itself while in a non-inflated condition and maintaining it in the non-inflated condition with a closure  124 . As before, an attachment flap  170  can be provided, if desired, with an adhesive strip backing  174  for attaching the gathered portion to the body of the patient. When deployed, the unfurled gathered portion ends in a lower edge  180  at the feet of the patient  12 . The primary edge  126  of the released closure remains attached to the surface  122  of the blanket, as illustrated in FIG.  7 . 
     FIGS. 8 and 9 illustrate an alternative embodiment of a blanket  200  for providing access to the lower extremities of the patient. FIG. 8 shows that the blanket can be draped over a patient so that the longest dimension of the blanket extends across the body of the patient from arm to arm. Two gathered portions  210 ,  212  define a central area  214  of the blanket, which covers the torso of the patient and bridges a blanket lower end  216  and a blanket upper end  218 . The lower end and upper end are each provided with an inlet port  18  but communicate internally so that both ends are simultaneously inflated even if only one port is connected to an inflating medium. An optional head drape  220  can be provided to maintain the temperature of the patient&#39;s head. The blanket  200  also includes, in its upper end  218 , a removeable section  219  defined by a U-shaped perforation  221 . The removeable section  219  can be removed by tearing along the perforation  221  to leave a U-shaped indentation in the upper end edge  223 . The indentation is indicated at  224  in FIG.  9 . FIG. 9 shows the blanket  200  after medical care has been provided and the gathered portions have been released. As can be seen in FIG. 9, after the gathered portions are released, the blanket  200  is preferably rotated so that the longest dimension of the blanket is oriented over the length of the patient&#39;s body with the patient&#39;s head received in the U-shaped indentation  224 . Thus, complete coverage of the patient is obtained. 
     FIGS. 10-12 illustrate an embodiment  300  of the thermal blanket in which access is provided to the lower extremities of the patient  12  in general, and to the legs of the patient in particular. FIG. 10 shows that the thermal blanket has an overall shape that includes a primary portion having a relatively large, generally rectangular upper body portion  310  placed over the upper body of the patient  12  and a relatively narrow, elongated central lower body extension  312  having a width substantially less than the width of the upper body portion. In the preferred embodiment of FIGS. 10-12, the lower body extension  312  comprises a single inflatable tube of the type illustrated in FIGS. 3 and 4 that is used to cover at least one elongated member of the patient, such as a leg. Whereas the upper body portion comprises a plurality of inflatable tubes that are arranged transversely of the upper end of the lower body extension and are used to cover the chest area of the patient. The elongated central extension  312  and the transverse upperbody tubes  310  communicate internally so that a single inlet port  18  permits them to be simultaneously inflated. 
     FIG. 10 also shows that the lower end of the elongated lower body extension  312  is flanked by two gathered portions  314 ,  316 . Each gathered portion includes an attachment flap  322  with an adhesive backing along its underside, as described previously for the other embodiments. Other attachment flaps can be provided at other blanket portions as desired, such as the attachment flaps  324  for securing edges of the upper body portion  310  to the patient  12 . A head drape  326  also can be provided. FIG. 11 shows a first one  314  of the gathered portions in its deployed condition, while FIG. 12 shows the thermal blanket with both gathered portions in their respective deployed conditions, wherein full coverage of the patient is provided. 
     More particularly, FIG. 10 shows both of the gathered portions  314 ,  316  in their non-inflated condition and shows that they are coupled to the central extension  312  of the blanket  300  along the length of the central extension, on opposite sides. Each gathered portion  314 ,  316  has a closure  315 ,  317 , respectively, that maintains the gathered portions in their non-inflated condition. FIG. 11 shows the blanket  300  after the closure  315  of the first gathered portion  314  has been opened, or removed, thereby permitting the inflating medium to enter the first gathered portion and inflate the first gathered portion so that it deploys transversely of the central extension  312 . In FIG. 11, the closure  317  of the remaining second gathered portion  316  has not been removed and therefore that gathered portion remains in the non-inflated condition. FIG. 12 shows the blanket  300  after the closure  317  of the second gathered portion  316  also has been opened and after the second gathered portion has been inflated and deployed transversely of the central extension. 
     FIGS. 13 and 14 illustrate a blanket  400  similar to that shown in FIGS. 10-12, except that the blanket  400  leaves the arms of the patient  12  exposed and covers the lower extremities of the patient. Thus, the lower end  412  of the blanket covers the patient&#39;s lower extremities and the upper end  414  includes the gathered portions. Again, the primary portion of the blanket includes a relatively large portion  416  and a central extension  418  that is flanked by two gathered portions  420 ,  422 . The gathered portions, typically are deployed after medical care has been provided (FIG. 14) and it is desired to obtain full coverage of the patient. Lateral drapes  424  can be provided for supplemental coverage, if desired. 
     The closure  24  of a thermal blanket constructed in accordance with the present invention can assume a variety of structures in addition to the pull strip described above. In FIG. 15, the closure comprises a tear string  510  that is embedded in the elongated strip  524  of the closure. Once again, the elongated closure strip includes a first edge  526  attached to the primary portion  14  of the blanket  10  and a second edge  528  attached to the gathered portion  16 . The tear string includes an enlarged release tab  512  that can be grasped and pulled, tearing the string out from the elongated strip and thereby separating the edge of the elongated strip attached to the primary portion of the blanket from the edge of the elongated strip attached to the gathered portion. As before, an optional attachment flap  70  can be provided, having a free end  72  with an adhesive backing  74  applied to the underside and having a central perforation  76  for easy removal. 
     FIG. 16 shows a closure  24  comprising a hook and loop fastening system  610 , such as commonly sold, for example, under the trademark “VELCRO.” The hook and loop fastening system includes a hook strip  612  having loops or coils  613  of a plastic material and a loop strip  614  having a loose, or fuzzy, pile of material. The hook strip can be engaged with the loop strip and then released by forcibly pulling them apart. Although relatively modest forces will not separate the two strips, more deliberate pulling actions can be used to easily separate the hook strip from the loop strip. When engaged, the hook and loop fastening system provides a unitary strip that can be attached to the thermal blanket so as to maintain the gathered portion in the non-inflated condition. 
     In FIG. 16, the looped plastic material is attached to the underside of a first edge  616  of the hook strap, which then is attached to the gathered portion  16  along a second edge  618 . Preferably, the attachment is by an adhesive backing. The loop strip  614  is attached to the primary portion  14  of the thermal blanket. It should be noted that the hook strip and loop strip can be mounted on the opposite blanket portions. To hold the gathered portion  16  in the non-inflated condition, the bottom of the first edge  616  is pressed into engagement with the loop strip  614 . When it is desired to unfurl the gathered portion, the hook and loop fastening system is simply separated by pulling on the two respective strips in opposite directions. This releases the hook strip from the loop strip and permits the gathered portion to be unfurled, admitting the inflating medium into the gathered portion. As before, an attachment flap  70  can be included with the closure  610 . 
     Thus, all of the embodiments described above provide an inflatable thermal blanket that can be used to permit access to a site of interest while controlling a patient&#39;s body temperature during surgery and then can be converted to a full-body covering that completely covers the patient. 
     The present invention has been described above in terms of presently preferred embodiments so that an understanding of the present invention can be conveyed. There are, however, many configurations for inflatable thermal blankets not specifically described herein but with which the present invention is applicable. For example, the closure can be provided by a light tackiness adhesive backing. The present invention should therefore not be seen as limited to the particular embodiments described herein, but rather, it should be understood that the present invention has wide applicability with respect to inflatable thermal blankets generally. All modifications, variations, or equivalent arrangements that are within the scope of the attached claims should therefore be considered to be within the scope of the invention.

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