Abstract:
An organ support apparatus includes: an enclosure having a floor, opposed side walls, opposed end walls, and a lid; a first support pad disposed on the floor of the enclosure, the first support pad comprising a plurality of inflatable and flexible chambers; and an inflation apparatus coupled to the chambers and operable to individually inflate or deflate each chamber.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    This invention relates generally to organ support and bypass processes, and more particularly to methods and apparatus for physically supporting an organ during such processes. 
         [0002]    Numerous medical procedures require circulation of a fluid through an internal organ, optionally with treatment of the fluid by processes such as filtering, oxygenation, and the like. For example, when an organ is harvested from a donor for transplantation, a neutral saline solution is used to flush out the donor&#39;s blood from the blood vessels of the organ. 
         [0003]    It is also known that some devices use a similar process to circulate an aqueous organ preservation fluid, such as “Belzer&#39;s solution”, through organs which have been harvested for transplantation. This action sustains the organ while it is outside the body by attempting to preserve functioning, and increases the limited “shelf life” of transplant organs compared to conventional chilled storage. 
         [0004]    More advanced concepts provide methods and apparatus for supporting an organ (in vivo or in vitro) in a manner which closely mimics biological processes by providing carefully controlled fluid pressure and chemical profiles. One such concept is described in published U.S. patent application 2010/0028979 entitled “Methods And Apparatus For Organ Support”. 
         [0005]    All of these processes and devices require that an internal organ be physically supported outside the body, typically in a rigid or resilient static container. Thus supported, gravity forces on the organ tend to press it against whatever support is used underneath it, resulting in localized pressure on its lower and lateral surfaces. This can result in localized pressure ischemia, cellular damage and/or loss of organ function and vitality. 
       BRIEF SUMMARY OF THE INVENTION 
       [0006]    These and other shortcomings of the prior art are addressed by the present invention, which provides an articulating organ support. 
         [0007]    According to one aspect of the invention, an organ support apparatus includes: an enclosure having a floor, opposed side walls, opposed end walls, and a lid; a first support pad disposed on the floor of the enclosure, the first support pad comprising a plurality of inflatable and flexible chambers; and an inflation apparatus coupled to the chambers and operable to individually inflate or deflate each chamber. 
         [0008]    According to another aspect of the invention, a method for supporting an organ, includes: providing an enclosure adapted to contain an organ; placing the organ on a first support pad disposed on a floor of the enclosure, the first support pad comprising a plurality of inflatable and flexible chambers; and selectively inflating and deflating the chambers to provide a time-varying contact pressure profile with the organ. 
         [0009]    According to yet another aspect of the invention, a method for supporting an organ includes: providing an enclosure adapted to contain an organ, the enclosure having a floor opposite a lid; placing a first support pad against the floor, the first support pad comprising a plurality of inflatable and flexible chambers; placing a second support pad against the lid, the second support pad comprising a plurality of inflatable chambers; placing the organ between the first and second support pads; inflating the chambers to clamp the organ in position between the support pads; and selectively tilting or rotating the enclosure to provide a time-varying contact pressure profile between the first and second support pads and the organ. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    The invention may be best understood by reference to the following description taken in conjunction with the accompanying drawing figures in which: 
           [0011]      FIG. 1  is a schematic view of a organ support apparatus constructed according to an aspect of the present invention, coupled to a perfusion system; 
           [0012]      FIG. 2  is top view of the organ support apparatus of  FIG. 1 ; 
           [0013]      FIG. 3  is a partially-sectioned side view of the organ support of  FIG. 2 ; 
           [0014]      FIG. 4  is a partially-sectioned end view of the organ support of  FIG. 2 ; 
           [0015]      FIG. 5  is a top view of a support pad of the organ support apparatus; 
           [0016]      FIG. 6  is a side view of the support pad of  FIG. 5 ; 
           [0017]      FIG. 7  is a front end view of the support pad of  FIG. 5 ; 
           [0018]      FIG. 8  is a rear end view of the support pad of  FIG. 5 ; 
           [0019]      FIG. 9  is a schematic diagram of a support pad coupled to an inflation apparatus; 
           [0020]      FIG. 10  is a side view of an organ support apparatus including a rotation apparatus; 
           [0021]      FIG. 11  is a side view of the organ support apparatus of  FIG. 10  in an inverted position; 
           [0022]      FIG. 12  is a schematic end view of a support pad in a first configuration; and 
           [0023]      FIG. 13  is a schematic end view of a support pad in a second configuration. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0024]    Referring to the drawings wherein identical reference numerals denote the same elements throughout the various views,  FIG. 1  depicts diagrammatically a perfusion system  10  suitable for circulating a fluid through an organ, in conjunction with an organ support apparatus  12  which is constructed in accordance with the present invention. As used herein the term “perfusion system” broadly refers to any apparatus which functions to circulate fluid through an organ and could range from a simple saline flushing device to a highly sophisticated organ support apparatus such as the one described in U.S. published patent application 2010/0028979 entitled “Methods And Apparatus For Organ Support”. The perfusion system  10  comprises a fluid circuit defined by plastic tubing or another suitable type of conduit, connected to an organ, depicted generally at “K”, by an inlet line  14  and an outlet line  16 . 
         [0025]    The perfusion system  10  includes some means for circulating fluid, such as a pump, along with appropriate fluid treatment equipment, such as one or more filters, heat exchangers, oxygenators, de-aerators, or chemical injectors. All of this equipment is depicted schematically at number  18 . An electronic controller  20  may be used to control the operation of the perfusion system  10 . The illustrated example is explained in the context of providing support for a kidney K which is contained in the organ support apparatus  12  and connected to a fluid collection container  22  which receives a fluid flow from the kidney K. However, it will be understood that the principles of the present invention are broadly applicable to support of many types of organs. The fluid collection container  22  may not be needed for other organs. 
         [0026]    The basic components of the organ support apparatus  12  are an enclosure  24 , a lower support pad  26 , an optional upper support pad  28 , and an inflation apparatus  30 . 
         [0027]    Optionally, an imaging device  31  (such as a camera operating in the visual, UV, or IR frequency ranges) may be used to observe the condition of the organ K through the enclosure  24 . One example of a suitable imaging device is a confocal microscope such as the VIVASCOPE device available from Lucid, Inc., Rochester, N.Y. 14623 USA. Positioning apparatus (not shown) capable of multi-axis positioning may be provided to point the imaging device  31  at a particular target area of the organ K. 
         [0028]      FIGS. 2-4  illustrate the organ support apparatus  12  in more detail. The organ enclosure  24  provides physical protection to the organ K and isolates it from the external environment. Preferably the material of the enclosure  24  is transparent to visible light and/or other select portions of the radio frequency (“RF”) spectrum to facilitate imaging of the organ K. For example, it may be constructed from a material such as sterilizable transparent medical-grade polymer. As illustrated it is in the form of a rectangular box with a floor  32 , side walls  34 , front and rear walls  36  and  38 , and a removable lid  40 . The lid  40  may be secured with latches  42 . The front wall  36  is provided with pass-through openings for making connections between the artery “A” and vein “V” of the kidney K (for example) and the inlet and outlet lines  14  and  16  respectively of the perfusion system  10 . There is also a pass-through opening for making a connection to the ureter U, to allow urine to drain to the fluid collection container  22  (see  FIG. 1 ). 
         [0029]    The lower support pad  26  rests on the floor  32  and the organ K rests on top of the lower support pad  26 . The lower support pad  26  shown in more detail in  FIGS. 5-8 . It is constructed from a top sheet  44  and a bottom sheet  46  which are selectively bonded together along their mutual peripheral edges  48  and along dividing seams  50 . The remaining unbonded portions define individual inflatable and flexible chambers  52 A through  52 E. The sheets  44  and  46  may be made from any flexible, fluid-tight material, such as polymers, treated fabrics, or rubber. Preferably the material is transparent to visible light and/or other select portions of the radio frequency (“RF”) spectrum to facilitate imaging of the organ K. The sheets  44  and  46  may be bonded together by any method which provides a leak-tight connection, such as by thermal or ultrasonic bonding, adhesives, or crimping. 
         [0030]    In the illustrated example, there are five side-by-side, elongated, generally rectangular chambers  52 A through  52 E. As will be explained further below, the shape, number, and configuration of the chambers  52 A through  52 E is not critical and could be varied in a number of ways to suit a particular application. For example, various patterns of elongate shapes, grid patterns, and/or arcs or circles could be used to define the chambers. A fluid connection is provided to each of the individual chambers  52 A- 52 E. As shown, individual tube fittings  54  are employed. 
         [0031]    If used, the upper support pad  28  would be identical in construction to the lower support pad  26 . The upper support pad  28  would be placed between the organ K and the lid  40 . 
         [0032]    An inflation apparatus (shown schematically at  30  in  FIG. 1 ) is provided for selectively inflating and deflating each chamber  52 A- 52 E.  FIG. 9  shows an example of the inflation apparatus  30  in a basic form comprising a controller  56  coupled to an air pump  58  which is in turn coupled to the individual chambers  52 A- 52 E of the lower support pad  26  through tubes  60 . Water or another liquid could be used instead of air. The pump  56  may be a pressure pump only, or it may be a combination pressure/vacuum pump to provide for improved deflation. The controller  56  may be a general-purpose microcomputer of a known type, such as a PC-based computer, or it may be a custom processor, or may incorporate one or more programmable logic controllers (PLC). Depending on the type of perfusion system  10 , the pump  58  may be controlled through software programming integrated into the perfusion system controller  20  (see  FIG. 1 ). As shown in  FIG. 9 , the pump  58  is connected to the chambers  52 A- 52 E through a multi-port remotely-controlled valve  62  whose position is commanded by the controller  56 . Alternatively, an independent pump could be provided for each chamber  52 A- 52 E. If an upper support pad  28  is used, a separate inflation apparatus  30  (see  FIG. 1 ) may be provided for it, or the valve  62  could be modified to accommodate additional chambers of the upper support pad  28 . 
         [0033]    Optionally, the capabilities of the support apparatus  12  may be further extended by providing apparatus for pivoting or rotating the enclosure  24 .  FIG. 10  illustrates an enclosure  24  with shafts  64  and  66  extending from the front and rear walls  36  and  38 , respectively, and mounted in pivot bearings  68  which are in turn held by stands  70 . An electric motor  72  (for example a stepper motor), or other suitable type of rotary device, is coupled to one of the shafts  64  or  66 . Rotation of the shaft of the motor  72  pivots the enclosure  24  about the shafts  64  and  66 . This function may be used to tilt the organ K (not seen in  FIGS. 10 and 11 ) to specific angles or to periodically invert it during a perfusion procedure (the inverted position is shown in  FIG. 11 ). If desired, a multi-axis gimbal of a known type may be employed to mount the enclosure  24  so that it may be rotated about more than one axis. 
         [0034]    The operation of the organ support apparatus  12  will be described with reference to  FIGS. 12 and 13 . An organ K is placed on the lower support pad  26  within the enclosure  24 . The organ K is connected to the perfusion system  10  which is placed in operation circulating fluid through the organ K. While the organ K is resting on the lower support pad  26 , the chambers  52 A- 52 E are selectively inflated and deflated so as to provide a varying contact pressure profile with the organ K. For example,  FIG. 12  shows chambers  52 A,  52 C, and  52 E as being fully inflated while chambers  52 B and  52 D are deflated. In this configuration the organ K is supported along three spaced-apart lines, and points of relatively higher pressure are present at the locations marked with arrows “P 1 ”. At a subsequent time, chambers  52 B and  52 D may be fully inflated while chambers  52 A,  52 C, and  52 E are deflated. This configuration is shown in  FIG. 13 . The organ K would thus be supported along two spaced-apart lines and points of relatively higher contact pressure are present at the locations marked with arrows “P 2 ”. The locations P 1  are relieved of pressure, allowing free flow of circulation and absence of mechanical stress. This cycle of alternating inflation and deflation may be repeated as often as necessary so that no one portion of the organ K is subjected to damaging pressure for too long, which could result in localized pressure ischemia. For example, the pressure in any one location may be relieved about 2 or 3 times per minute. 
         [0035]    If the rotation apparatus described above are used, then the enclosure  24  with the organ K may be periodically tilted and/or inverted so that contact pressures on the organ K are shared between its opposite surfaces. For example, the organ K may be tilted and/or inverted with a frequency of about once per minute to about once every 30 minutes. The frequency is subject to the vascular resistance and condition of the organ K or tissue. The tilt and/or inversion may be in addition to or as an alternative to the selective inflation and deflation of the chambers  52 A- 52 E. The imaging device  31 , such as a scanning high resolution infrared camera may be employed to take a series of images an build therefrom a mosaic image of the organ K for localized and global comparison. For example, the organ K may be imaged in small blocks, e.g. 20 mm×20 mm (0.8 in.×0.8 in.). In the image, ischemic areas will exhibit relatively higher or lower temperatures than the surrounding tissue. 
         [0036]    In response to the detection of such areas, the controller  56  may be programmed to tilt and/or invert the organ enclosure  24 , and/or to selectively inflate or deflate the chambers  52 A- 52 E. To facilitate the imaging and control process, the temperature of the fluid circulating through the organ K may be altered (e.g. using the perfusion system  10 ) slightly up and down from a physiologically suitable temperature for organ characterization and preservation. For example, the fluid temperature change may be plus or minus about 2 degrees C. (plus or minus about 3.6 degrees F.) Any ischemic areas will respond to the fluid temperature change at a substantially slower rate than the surrounding tissue, resulting in hot or cold spots which can be detected by the imaging device  31 . 
         [0037]    The upper support pad  28  may be used to supplement the lower support pad  26 . For example, if the enclosure  24  is inverted, then the organ K would rest on the upper support pad  28  and the alternate chamber inflation cycle described above would be carried out using the upper support pad  28 . The upper support pad  28  may also be used simultaneously with the lower support pad  26  to provide a gentle clamping action to the organ K in order to support it during tilting and/or inversion, or during movement or transport of the enclosure  24 . 
         [0038]    The foregoing has described an organ support apparatus and methods for its operation. While specific embodiments of the present invention have been described, it will be apparent to those skilled in the art that various modifications thereto can be made without departing from the spirit and scope of the invention. Accordingly, the foregoing description of the preferred embodiment of the invention and the best mode for practicing the invention are provided for the purpose of illustration only and not for the purpose of limitation.