Patent Publication Number: US-9420895-B2

Title: Patient support

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. provisional application U.S. provisional application Ser. No. 61/697,010 (P405) filed Sep. 5, 2012, entitled PATIENT SUPPORT, which is incorporated by reference herein in its entirety. 
     This application is related to U.S. provisional application Ser. No. 61/837,067 (P405A) filed Jun. 19, 2013, entitled PATIENT SUPPORT COVER Ser. No. 61/507,371, filed Jul. 13, 2011, entitled PATIENT/INVALID HANDLING SUPPORT; copending U.S. application Ser. No. 13/548,591, filed Jul. 13, 2012, entitled PATIENT/INVALID HANDLING SUPPORT; U.S. copending application Ser. No. 13/022,326, filed Feb. 7, 2011, entitled PATIENT/INVALID HANDLING SUPPORT; U.S. copending application Ser. No. 13/022,372, filed Feb. 7, 2011, entitled PATIENT/INVALID HANDLING SUPPORT; U.S. copending application Ser. No. 13/022,382, filed Feb. 7, 2011, entitled PATIENT/INVALID HANDLING SUPPORT; U.S. copending application Ser. No. 13/022,454, filed Feb. 7, 2011, entitled PATIENT/INVALID HANDLING SUPPORT; U.S. copending application Ser. No. 12/640,770, filed Dec. 17, 2009, entitled PATIENT SUPPORT; and U.S. copending application Ser. No. 12/640,643, filed Dec. 17, 2009, entitled PATIENT SUPPORT. 
    
    
     TECHNICAL FIELD AND BACKGROUND OF THE INVENTION 
     The present invention generally relates to a patient support, and more particularly to a patient mattress for a hospital bed. 
     SUMMARY OF THE INVENTION 
     The present invention provides a mattress for supporting a patient with one or more cushioning layers that provide immersion and pressure distribution to a patient supported on the mattress. 
     In one form of the invention, a patient support includes a plurality of cushioning layers arranged such that their supporting surfaces when unloaded are generally arranged in a plane. Each cushioning layer is interlocked with each adjacent cushioning layer wherein each cushioning layer provides lateral and longitudinal support to each of its adjacent cushion layers. 
     In one aspect, the cushioning layers include a bladder layer. 
     In another aspect, the cushioning layers include a gel layer. 
     According to yet another aspect, at least one of the cushioning layers includes transverse openings allowing air to pass through the at least one cushioning layer to direct air flow through the at least one cushioning layer. 
     In any of the above supports, the patient support may include a plurality of inflatable bladders and a gel layer adjacent the inflatable bladders. For example, the gel layer may interlock with adjacent bladders of the inflatable bladders. 
     In another aspect, each of the bladders has a hexagonal cross-section. In addition or alternately, the gel layer may include a plurality of hexagonal gel footings. For example, each of the gel footings may be disconnected from its adjacent gel footings. Optionally, each of the gel footings may be internally reinforced by a plurality of hexagonal gel wall structures. 
     According to yet another aspect, the cushioning layers are supported on a foam crib. 
     In addition, the support optionally includes turning bladders positioned below the foam crib, with the foam crib including at least two hinged panels to allow turning of a patient supported on the patient support. 
     In another aspect, the support includes a cover and is configured to flow air through the support beneath the cover to manage moisture that may build up under the cover, which is formed from a material that prevents liquid intrusion but allows gas and moisture to flow through the cover. 
     For example, the foam crib may include a plurality of channels extending there through for directing air through the foam crib and into at least one of the cushioning layers. Additionally, the foam crib may support or house one or more blowers to direct air though the channels. 
     In another aspect, the support cover includes a mesh panel that permits air to be drawn into the cover by the blower units. 
     Accordingly, the present invention provides a support surface that provides a patient with pressure distribution and optionally improved moisture management. 
     Before the embodiments of the invention are explained in more detail below, it is to be understood that the invention is not limited to the details of operation or to the details of construction and the arrangement of the components set forth in the following description or illustrated in the drawings. The invention may be implemented in various other embodiments and is capable of being practiced or being carried out in alternative ways not expressly disclosed herein. Also, it is to be understood that the phraseology and terminology used herein are for the purpose of description and should not be regarded as limiting. The use of “including” and “comprising” and variations thereof is meant to encompass the items listed thereafter and equivalents thereof as well as additional items and equivalents thereof. Further, enumeration may be used in the description of various embodiments. Unless otherwise expressly stated, the use of enumeration should not be construed as limiting the invention to any specific order or number of components. Nor should the use of enumeration be construed as excluding from the scope of the invention any additional steps or components that might be combined with or into the enumerated steps or components. 
    
    
     
       DESCRIPTION OF THE FIGURES 
         FIG. 1  is a perspective view a patient support shown mounted to a patient support apparatus, for example, a hospital bed; 
         FIG. 2  is a perspective view of the patient support of  FIG. 1 ; 
         FIG. 2A  is an exploded fragmentary view of the patient support illustrating the various cushioning layers and components that may be incorporated into the patient support; 
         FIG. 3  is a similar view to  FIG. 2  with the cover removed to show the internal cushioning layers; 
         FIG. 3A  is a plan view of the patient support illustrating the different areas or zones of the patient support; 
         FIG. 4  is a perspective view of the bladder layer of the patient support; 
         FIG. 4A  is a perspective view of the bladder layer with a partial cut-away illustrating the construction of at least some of the bladders; 
         FIG. 4B  is an enlarged top perspective view of a portion of the bladder layer of the patient support; 
         FIG. 5  is a perspective view of the foam crib that supports the bladder layer; 
         FIG. 6  is a bottom perspective view the foam crib of  FIG. 5  illustrating the foam crib with a hinged panel; 
         FIG. 7  is a perspective view of the base of the patient support; 
         FIG. 8  is a perspective view of a pair of turning bladders; 
         FIG. 9  is a perspective view of the gel layer of the patient support; 
         FIG. 9A  is an enlarged plan view of a gel footing of the gel layer of  FIG. 9 ; and 
         FIG. 10  is a similar view to  FIG. 3  illustrating a patient supported on the surface and illustrating the immersion of the patient&#39;s body into the surface. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to  FIG. 1 , the numeral  10  generally designates a patient support of the present invention. While described as a “patient” support, it should be understood that “patient” is to be construed broadly to include not only people undergoing medical treatment but also invalids and other persons, such as long term care persons, who may or may not be undergoing medical treatment. Further, while patient support  10  is illustrated as a mattress, it will be understood that patient support  10  may take on other forms, such as pads, cushions, including cushions for a wheelchair or a stationary chair pads. As will be more fully described below, patient support  10  provides support to a patient&#39;s body and, further, may be adapted to provide therapy or treatment to the patient, for example, rotation therapy, percussion therapy, or vibration therapy or the like. Additionally, the support surface of the patient support may be configured to provide a control system that automatically determines a suitable immersion level for each individual patient that is positioned on the support, thereby creating an individualized immersion level that is tailored to that specific individual. For further details of a suitable immersion control system reference is made to copending application U.S. Ser. No. 61/696,819, filed Sep. 5, 2012, entitled INFLATABLE MATTRESS AND CONTROL METHODS, which is incorporated by reference herein in its entirety. 
     Referring again to  FIG. 1 , patient support  10  is supported on a patient support apparatus  12  that, in this particular embodiment, is a hospital bed. However, patient support apparatus  12  may take on other forms besides a hospital beds, such as, but not limited to, long term care, cots, stretchers, operating tables, gurneys, and the like. Further, patient support apparatus  12  may be a conventional support apparatus that is commercially available and that merely provides a supporting function for patient support  10 . 
     For example, patient support apparatus  12  may include one or more controls that are integrated therein and which are used in controlling one or more functions of patient support  10 , as will be discussed in greater detail below. For example, electrical connectors may be provided for establishing an electrical link between a user interface that is positioned on, or integrated into, the barrier of patient support apparatus  12 . The user interface may take on a variety of different forms, such as, but not limited to, a touch screen, a Liquid Crystal Display (LCD), a plurality of buttons, switches, knobs, or the like, or any combination of these components, which allows a user to control the operation of patient support  10 . The connection between the interface and patient support  10  may take on different forms, including a direct electrical cable that runs from the footboard to patient support  10 , for example by way of electrical connectors that electrically couple the user interface to circuitry supported on or in the frame of the bed, and/or by wireless communication, such as disclosed in commonly assigned, U.S. patent application Ser. No. 13/802,855, filed Mar. 14, 2013, by applicants Michael Hayes et al. and entitled COMMUNICATION SYSTEMS FOR PATIENT SUPPORT APPARATUSES, the complete disclosure of which is hereby incorporated herein by reference. For more exemplary details of a suitable hospital bed reference is made to the beds described in U.S. Pat. Nos. 8,006,332; 7,690,059; 7,805,784; 7,962,981; and 7,861,334, all commonly owned by Stryker Corporation of Kalamazoo, Mich., which are herein incorporated by reference in their entireties. 
     Referring to  FIG. 2 , patient support  10  includes a cover  14 , which provides a plurality of optional features. For example, cover  14  may be formed from a flexible knit material, such as a flexible knit nylon or a nylon-like fabric, which provides a high breathability rate to facilitate moisture management. Additionally, cover  14  may be formed with the knit fibers on the patient facing side of the cover and with an inner surface formed by a stretchy elastomeric membrane that is stretchable so as not to reduce, if not eliminate, any interference with the patient immersion into support  10 , as will be more fully described below. Furthermore, as will be more full described below, because cover  14  optionally encloses one or more blowers or fans for circulating air through the support, as part of a low air loss system, cover  14  may incorporate an open mesh panel to allow air to be drawn into the cover  14 . 
     In another aspect, cover  14  may include one or more indicia on its surface. For example, cover  14  may include indicia to define the preferred location for a patient on patient support  10 . The indicia may include a demarcation  16 , such as a line, that defines the overall general area in which the patient should be positioned in the supine position and additional demarcations  18 ,  20 ,  22 , and  24 , also for example lines, that define the foot area, the thigh and seat areas, the back areas, and the head area of the patient support. In this manner, when a patient is located in the general area and also generally aligned with the sub-areas, the patient will be properly aligned with the support cushioning layers and turning bladders that are configured to provide the appropriate cushioning and functionality to that region of the patient&#39;s body. 
     In addition to the demarcation lines that identify the different areas/sections of the support, other indicia may be applied for example, graphical instructions, representations of the underlying cushioning layers (e.g. the gel or bladders), as well as the location of optional percussion/vibration and/or turning bladders to again facilitate the proper positioning of the patient. 
     The various demarcations, which for example indicate the different areas of support, i.e. thigh and back support areas, foot support areas, and head support areas, may be applied to the underlying sheet that forms the cover using a heat transfer process. For example, ink that is applied to a carrier sheet may be transferred onto the fabric that forms the cover using heat. In this manner, the ink does not simply coat the fabric, as is the case with silk screening, and instead merges with the fabric (and optionally underlying elastomeric membrane) which provides the sheet with generally constant properties. This tends to reduce the wear and provide increased longevity to the demarcations. 
     To provide appropriate cushioning and immersion for the patient, patient support  10  includes a bladder layer  26  with a plurality of bladders  26   a ,  26   b , which provide support to the patient&#39;s thighs, seat, back, and head, and a gel layer  28 , which provides support to the patient&#39;s heels. Bladder layer  26  may be formed from a sheet of gelatinous elastomeric material, which is configured, such as by molding, including injection molding, blow molding, thermoforming, or cast molding, to include a plurality of sacs or cavities, which form upper wall  26   c  and side walls  26   d  of each bladder  26   a ,  26   b , which is then joined with a bottom sheet  26   e  to form the closed chambers of the bladders (see  FIG. 4A ). The two sheets are joined together around their respective perimeters and around each of the sacs to form an array of discrete bladders. At least some regions of the sheets may be left un-joined (for example see in  FIG. 4A ) to form fluid passageways between some or all of the adjacent bladders so that a network of passageways can be formed in the bladder layer to allow air flow between at least some of the bladders, which reduces the amount of tubing that is require to inflate the bladders and to maintain the pressure in the bladders at the desired pressure value. As noted below, some bladders may be grouped together in that they are in communication with each other through the above-noted air passageways, or through tubing, so that the bladders form zones. 
     Referring to  FIG. 2 , bladder layer  26  and gel layer  28  are supported so that their top or patient facing surfaces are adjacent each other and positioned generally in the same plane and at the same height (when not loaded with a patient) to form a generally continuous layer of cushioning. Though as noted below, at the interface between the gel layer and the bladders layer, the gel layer may be slightly angled downwardly to provide a more comfortable transition between the adjacent cushion layers. 
     In the illustrated embodiment, bladders  26   a ,  26   b  are arranged in zones, which optionally may be independently controlled with the inflation/deflation of each zone independent of the other zone or zones. For example, the zones may include a head zone at the head end  10   a  of support  10 , a back zone at the back section  10   c  of support  10 , seat and thigh zones at the seat and thigh sections  10   d , and a heel zone at the foot end  10   b  of patient support  10 . Further, each zone may be divided, for example into a left sub-zone and a right sub-zone so that when a patient is being turned, the pressure on the bladders on one side may be adjusted (e.g. increased or decreased) to accommodate the motion of the patient. For example, in the illustrated embodiment, the seat zone includes a right seat zone and a left seat zone to facilitate turning the patient. In the illustrated embodiment, the back zone and the head zone are grouped together and, further, positioned so that they will generally be aligned together when the patient is positioned on support  10   
     Referring to  FIGS. 3 and 4 , bladders  26   a  are arranged in rows and columns (rows are transverse to the long axis of the patient support, with columns extending generally parallel to the long axis of the patient support), with each bladder  26   a  in each row offset longitudinally from the adjacent bladder  26   a  to form an alternating pattern in each row so that the bladders are nested with the bladders of the adjacent rows. Further, the lateral center line of each bladder  26   a  extends between its respective adjacent bladders. In the illustrated embodiment, bladders  26   a  each have a hexagonal cross-section so that each bladder edge is offset from the corresponding edge of the adjacent bladder. For further details of the bladder arrangement, materials, and construction, reference is made to copending U.S. patent application Ser. No. 13/022,326, filed Feb. 7, 2011, entitled PATIENT/INVALID HANDLING SUPPORT; Ser. No. 13/022,372, filed Feb. 7, 2011, entitled PATIENT/INVALID HANDLING SUPPORT; Ser. No. 13/022,382, filed Feb. 7, 2011, entitled PATIENT/INVALID HANDLING SUPPORT; Ser. No. 13/022,454, filed Feb. 7, 2011, entitled PATIENT/INVALID HANDLING SUPPORT; Ser. No. 13/548,591, filed Jul. 13, 2012, entitled PATIENT/INVALID HANDLING SUPPORT, all of which are incorporated by reference herein in their entireties. 
     Referring again to  FIGS. 3 and 4 , head section bladders  26   b  have a generally block-shaped configuration with the side of bladders  26   b  facing bladders  26   a  having recesses that correspond to the shape of bladders  26   a  to provide a smooth transition between the head end and back section bladders. Bladders  26   b  may also incorporate a cover  26   f  to tie both left side head end bladder and right side head end bladder together to provide uniform support to the patient&#39;s head except when the patient is being turned, as described below. 
     Gel layer  28  is formed from a gelastic material. Suitable gelastic materials include a SEB, SEBS, SEP, SEPS, SEEP, SEEPS polymer combined with a mineral oil, such as disclosed in U.S. Pat. Nos. 3,485,787; 3,676,387; 3,827,999; 4,259,540; 4,351,913; 4,369,284; 4,618,213; 5,262,468; 5,508,334; 5,239,723; 5,475,890; 5,334,646; 5,336,708; 4,432,607; 4,492,428; 4,497,538; 4,509,821; 4,709,982; 4,716,183; 4,798,853; 4,942,270; 5,149,736; 5,331,036; 5,881,409; 5,994,450; 5,749,111; 6,026,527; 6,197,099; 6,865,759; 7,060,213; 6,413,458; 7,730,566; and 7,964,664, which are all incorporated herein by reference in their entireties. 
     As one example, the gelatinous elastomeric material may be formulated with a weight ratio of oil to polymer of approximately 3.1 to 1. The polymer may be Kraton 1830 available from Kraton Polymers, which has a place of business in Houston, Tex., or it may be another suitable polymer. The oil may be mineral oil, or another suitable oil. One or more stabilizers may also be added. Additional ingredients—such as, but not limited to—dye may also be added. In another example, the gelatinous elastomeric material may be formulated with a weight ratio of oil to copolymers of approximately 2.6 to 1. The copolymers may be Septon 4055 and 4044 which are available from Kuraray America, Inc., which has a place of business in Houston, Tex., or it may be other copolymers. If Septon 4055 and 4044 are used, the weight ratio may be approximately 2.3 to 1 of Septon 4055 to Septon 4044. The oil may be mineral oil and one or more stabilizers may also be used. Additional ingredients—such as, but not limited to—dye may also be added. In addition to these two examples, as well as those disclosed in the aforementioned patents, still other formulations may be used. 
     In the illustrated embodiment, gel layer  28  includes a plurality of gelastic footings  29  that are disconnected from each other so that each footing can compress independently from its adjacent surrounding footing. The term footing is used in the sense that the overall gel structure (defined by outer perimeter wall  30 ) is wider than it is tall. Referring to  FIG. 9A , each footing  29  is formed by an outer perimeter wall  30 , having a generally hexagonal shape, which is then supported internally by six internal hexagonal-shaped walls  32 , which are arranged in a circular pattern to form a central hexagonal-shaped wall  36 . Central hexagonal-shaped wall  36  is formed by the respective inner walls of the six internal hexagonal-shaped walls  32 , which in turn share walls with the outer perimeter wall  30  and form six diamond shaped walls  34  therebetween. In other words, the central hexagonal-shaped wall  36  is not a separate wall and instead is defined by the inwardly facing walls of each internal hexagonal-shaped wall  32 . Similarly, the outer wall of each internal hexagonal-shaped wall  32  is provided or formed by a portion of the outer perimeter wall  30 . 
     For example, the height of each wall may be in a range of about 1″ to 4″, or in a range of about 2″ to 3″, and the thickness of each wall may be in a range of about 1/32″ to ⅜″ or in a range of about 1/16″ to/¼″. The width of each footing may be in a range of about 3″ to 6″ or in a range of about 4″ to 5″, with each internal hexagonal-shaped wall in a range of about 1″ to 2″ or in a range of about ¾ to 1½″. To facilitate injection molding, the walls are slightly tapered, for example, to create a draft angle. For example, the draft angle may fall in a range of about 1 degrees to 10 degrees or in a range of about 3 degrees to 8 degrees 
     In this manner, each gel footing  30  provides a nested set of interconnected gel walls that tend to buckle under the weight of a patient and continue to provide cushioning support to the patient&#39;s heels over the full range of collapse of each group of the internal walls. By spreading the load across multiple walls that are interconnected but arranged in isolated groups, each grouping will allow greater immersion and provide better redistribution of stress or pressure across the patient&#39;s heel then when all the walls are tied together. 
     In addition, each gel wall of each gel footing may be joined at their lowermost edges by a base sheet of gel, which is relatively thin, like a skin, which is used in the molding process to help distribute the gel material across the full width of the gel layer. 
     Further, the gel forming gel layer  28  may be selected to very soft, but with the interconnection of the adjacent inner walls still provide adequate support and cushioning to the patient&#39;s heel. For examples of other gel configurations that may be used, including gel columns (where the gel structures have a greater height than their width), reference is again made to U.S. Pat. Nos. 3,485,787; 3,676,387; 3,827,999; 4,259,540; 4,351,913; 4,369,284; 4,618,213; 5,262,468; 5,508,334; 5,239,723; 5,475,890; 5,334,646; 5,336,708; 4,432,607; 4,492,428; 4,497,538; 4,509,821; 4,709,982; 4,716,183; 4,798,853; 4,942,270; 5,149, 736; 5,331,036; 5,881,409; 5,994,450; 5,749,111; 6,026,527; 6,197,099; 6,843,873; 6,865,759; 7,060,213; 6,413,458; 7,730,566; 7,823,233; 7,827,636; 7,823,234; and 7,964,664, which are all incorporated herein by reference in their entireties. 
     As best seen in  FIG. 3 , bladder layer  26  and gel layer  28  are supported by a foam crib  40 . Crib  40  optionally includes a first portion  40   a  that extends under bladder layer  26  from the head end to the thigh region of the patient and a second portion  40   b  that extends under the gel layer from below the thigh region to foot end  10   b  of patient support  10 . Crib  40  tends to keep the softer cushion layers of the bladders and gel in place while also providing a firmer rail along both sides of support  10 . 
     Foam crib portion  40   a  includes a base wall  42  and a pair of upwardly extending sidewalls  44 , which as noted form a foam rail along opposed sides of bladder layer  26  to facilitate entry to and exit from the bed, and to cradle the patient when they are in the supine position. Referring to  FIGS. 5 and 6 , base wall  42  of crib  40  includes a plurality of channels that form a tree-like configuration with a central channel  46  and a plurality of laterally extending branch channels  48 , which are in fluid communication with central channel  46 . Central channels  46  in fluid communication with inlet or feeder channels  46   a  formed at the base of central channel  46 . And, each inlet channel  46   a  includes a recess  46   b  for receiving a blower unit  50 , whose output is directed toward the central channel  46  through inlet or feeder channel  46   a  and whose intake extends through the lower edge of base wall  42  so that when blower units  50  are covered by bladder layer  26 , the blower units can draw in air from the space adjacent the lower end of foam crib  40 , as will be more fully described below. These channels also facilitate the bending of foam crib, described below. 
     Blower units  50 , when operated, blow air into channels  46   a  and  46 , which in turn distribute the air into branch channels  48  to generate air flow into the bladder layer  26  from beneath. To allow the air to flow through bladder layer  26 , the base sheet  26   e  of bladder layer  26  includes a plurality of openings  26   g  ( FIG. 4B ) so that air can flow up through the bladder layer  26  and between the bladders  26   a  as indicated by the arrows in  FIG. 3 . To better focus the flow of air, base layer  42  may incorporate a sheet of non-woven material  54  ( FIGS. 2A and 6 ) adhered to its surface, which extends over inlet channels  46   a , central channel  46 , and portion of branch channels  48  to leave the distal end of each branch channel open so that they can direct air into the bladder layer  26  at discrete space locations. 
     Referring again to  FIG. 5 , each sidewall  44  of crib  40  has an upper wedge-shaped portion  60  adjacent at least the shoulder area of a patient supported on patient support  10 . Wedge-shaped portions  60  form angled surfaces facing the patient, at the patient&#39;s shoulder region, which extend above the upper surface of bladder layer  26  when inflated and unloaded, and extend above bladder layer  26  at an even greater height when a patient is placed on bladder layer  26 . Therefore, wedge-shaped portions  60  provide lateral support to a patient at their shoulders, but are sufficiently resilient to collapse down to the underlying base of sidewall  44  when a patient exits the bed. 
     Inwardly facing sides of sidewalls  44  optionally include a plurality of recesses  62  that at least generally follow the contour of each adjacent bladder  26   a  to thereby provide lateral support to each adjacent bladder both in the lateral and longitudinal direction. As a result, bladders  26   a  are held in place and, to a certain extent, somewhat interlocked with each other given their own interlocking arrangement. Similarly, as seen in  FIG. 3 , the inwardly facing edge of gel layer  28  may include a plurality of recesses to receive the bladders adjacent the gel layer so that the foot end bladders are similarly laterally and longitudinally supported by the adjacent gel layer. 
     As best seen in  FIG. 6 , foam crib portion  40   b  similarly has a base wall  64  with a pair of upwardly extending sidewalls  66  that similarly include recesses that generally match the shape of the respective gel footings and recesses formed between each gel footing. In a similar manner to the bladders, sidewalls  66  therefore provide lateral and longitudinal support to each of the adjacent gel footings that run along the edge of the gel layer  28 . In this manner, each layer is interlocked with its adjacent layer so that all three materials (foam, air-filled bladder, and gel) form a cushioning system. 
     Further, foam base wall  66  of foam crib section  40   b  includes a plurality of recesses to receive the lower ends of each bladder at the foot end of bladder layer  26  and, further, provide downwardly tapered upper surfaces adjacent each recess so that the gel footings at the thigh end of gel layer  28  are sloped downwardly to provide a smooth transition between the adjacent gel layer and bladder layer. This transition is optionally aligned generally between the knee and thigh of the patient supported on patient support  10 . 
     As best seen in  FIG. 2A , patient support  10  optionally includes a pair of turning bladders  70   a  and  70   b . Turning bladders  70   a ,  70   b  are positioned beneath crib  40 . Referring to  FIG. 5 , bladders  70   a  and  70   b  are aligned under sectioned portions  42   a  and  42   b  of base wall  42  of crib  40 , which are detached from the remainder of the crib along three sides to form hinged panels, which are hinged at the center of crib  40  so that they can lift up when one of the turning bladders is inflated. To prevent the hinged panel from falling into the crib, each panel optionally includes an L-shaped rim that generally aligns with a corresponding L-shaped sill in the balance of the crib that extends around the detached panels. 
     To deliver air to bladders  26   a  and  26   b  and to turning bladders  70   a  and  70   b , support  10  includes a pneumatic system. In this illustrated embodiment, the pneumatic system includes a pneumatic harness  80 , which includes a plurality of tubing sections  84  that are supported and secured to a fabric carrier that secures the various tubing sections and associated connectors  86  in their desired configuration and locations. In this manner, when harness  80  is placed over crib  40 , the tubing and its associated connectors can be easily aligned with the appropriate inlets for inflating the respective bladders. Together, the tubing and fabric carrier form a flexible manifold that can be easily located in a position with an inlet end (where the tubing exits the carrier) positioned and aligned for coupling to the pump or pumps that supply the air to the respective bladders. The pump or pumps that supply air to the tubing are optionally located in a box at the foot end of the support, more fully described below. 
     As noted above, the various tubing that supplies the bladders with air are coupled to a pump or pumps, which in the illustrated embodiment are located in a pump box  90  shown in  FIG. 7 . Pump box  90  is preferably located at the foot end  10   b  of the patient support  10  and further beneath the crib portion  40   b  under gel layer  28 . Pump box  90  for example may be formed from a polymeric material and has a centrally located recess typically located under the heels of a patient to provide increased immersion depth for the heels of the patient when the patient is lying on patient support  10 . In addition to storing or holding the pump or pumps, pump box  90  may also include a CPR manifold, which when opened allows the air from the bladders to be dumped so that the patient is then supported directly on the crib beneath the bladders, which provides a firmer surface to allow CPR to be administered to the patient. In addition to a pump or pumps, box  90  may also house various controls and circuitry for controlling the pump or pumps and for other devices that may be incorporated into patient support. 
     As noted above, bladders  26   a ,  26   b  are inflated, or deflated, in groups or zones as described above under the control of box  90  and its associated pumps and control circuitry. The fluid connections between the bladders and box  90  are established by the tubing  84  that run between box  90  and the various bladders and which connect to inlets on the bladders by connectors  86 . As noted above, tubing  84  is attached to housed in a fabric carrier which together form the flexible manifold  80 . 
     Similarly, manifold  80  may support the tubing for turning bladders  70   a ,  70   b , which extend generally longitudinally in a direction from the head end  10   a  to foot end  10   b , and as noted are positioned underneath foam crib  40  and are used to help turn a patient positioned on top of patient support  10 . To that end, turn bladders and are each separately and independently inflatable and deflatable, which is also controlled by box  90  and its associated circuitry. 
     For example, as discussed in reference to copending application U.S. Ser. No. 61/696,819, filed Sep. 5, 2012, entitled INFLATABLE MATTRESS AND CONTROL METHODS, patient support  10  may incorporate sensors, such as depth sensor plates  92 , for sensing the immersion of a patient into the surface. Based on the sensed immersion, the controller, which also may be located in box  90  or elsewhere, including for example in recesses  94  formed in foam crib  40  ( FIG. 5 ), may be used to optimize the immersion of a patient into the surface based on the individual needs of a patient. In order to assist depth sensor plates  92 , support  10  incorporates a conductive fabric  102 , which together function as capacitive sensors whose output changes as a patient moves closer or farther away from them. More specifically, conductive fabric  102  functions in a manner similar to the top plate of a parallel plate capacitor, while depth sensor plates  92  form the bottom plates of the parallel plate capacitor. Thus, as the vertical distance between conductive fabric  102  and any of the depth sensor plates  92  changes, the capacitance between the fabric  102  and the plate(s)  92  will change. This change is detected by a detector circuit that is electrically coupled between fabric  102  and each of the depth sensor plates  92 . That is, one or more wires (not shown) are electrically coupled to fabric  102  and the detector circuits, while one or more other wires (not shown) are connected between each plate  92  and the detector circuit. Conductive fabric  102  may be any commercially available fabric that is electrically conductive, or it may be an electrically conductive foil, or any other material that is electrically conductive, and that is flexible enough to not significantly alter the flexibility of patient support  10  in that region. 
     Fabric  102  is positioned on top of bladder layer  26  but over a fire sock or barrier  100 , which wraps around bladder layer  26  and is made of any suitable material that resists the spread of fire. Such materials may vary. In one embodiment, fire barrier  100  may be made of, or include, Kevlar® (poly-paraphenylene terephthalamide), or other brands of para-aramid synthetic fibers. Other materials may alternatively be used. Cover  14 , which includes an upper cover portion  14   a  and a lower cover portion  14   b , therefore encloses fabric  102 , sock  100 , bladder layer  26 , gel layer  28 , crib  40 , turning bladders  70   a ,  70   b , and plates  92 , as well as pump box  90  and the pneumatic manifold. For example, upper cover portion  14   a  and a lower cover portion  14   b  may be secured together by a zipper, which allows access to the various components inside support  10 . 
     As noted above, when one of the turning bladders is inflated, the corresponding hinged panel of foam crib will raise up. At the same time, the air in the bladders above the rising panel may either be maintained or increased, while the pressure on the bladders on the opposite side may be reduced or even deflated. 
     In addition to turning a patient, sections of patient support  10  may be folded to accommodate the Fowler being raised or the leg section of being lowered. For example, support  10  may be supported on a bed with an articulating deck, with a head section, a back section, a seat section and a leg section, with one or more sections being pivotable to raise the Fowler or leg sections as noted. To accommodate the articulating deck, foam crib may include a corresponding gatch for each point of articulation (see  FIG. 3 ). Further, cover  14  may include a V-shaped section (no shown) which extends into its underside and into one of the gatches to similarly accommodate the bending of support when one of the deck sections is pivoted. For example, the open mesh that was noted above may be located in the V-shaped section to allow air to be drawn into the cover when blower units are running to circulate air through the cover. Though it should be understood that the mesh panel may also be located elsewhere, including on a bottom side of cover  14 . 
     When assembled, therefore, patient support  10  not only includes a cushioning layer that provides a pressure redistribution system to enhance the support of a patient lying upon support  10  but also optionally provides a moisture management system, as well as an immersion control system. As noted above, additional functionalities may be provided in a form of configuring some of the bladders as percussion and/or vibration bladders, such as described in the referenced copending applications It should be understood that patient support  10  may be modified to include one or more bladders in the foot zone in lieu of the gel layer and, therefore, the air pressure inside of these bladders could be monitored and controlled by the same system that controls the feet section bladders, thigh and seat section bladders, and head section bladders. 
     Accordingly, the present invention provides a patient support that provides a mattress with inflatable support bladders that offer improved immersion of the patient into the surface of the mattress and, therefore, improved pressure distribution to the patient. With the independent discrete bladder arrangement, it has been found that a more balance contact (see  FIG. 10 ) can achieve in both the x and y-axes. Further, given the unitary nature of the support bladders, the need for tubing can be significantly reduced, and for some functions eliminated. 
     While several forms of the invention have been shown and described, other changes and modifications will be appreciated by those skilled in the relevant art. Therefore, it will be understood that the embodiments shown in the drawings and described above are merely for illustrative purposes, and are not intended to limit the scope of the invention which is defined by the claims which follow as interpreted under the principles of patent law including the doctrine of equivalents.