Abstract:
Methods and apparatus for producing saline slush for surgical applications. Producing surgical saline slush in a slush bottle that is a rigid or semi-rigid, high integrity, sturdy container that resists punctures and leaks to better maintain a sterile barrier and does not rely on having an external object placed in the fluid to mix the slush. Slush is agitated within the slush bottle. Slush bottle features are discussed which agitate and condition slush for use in medical procedures. The slush bottle may be rotated using a pair of rollers. A slush station may have one or more compartments for the production of slush and a basin shell for maintaining slush as slush in a basin. Specialized techniques for a vertical slush bottle are discussed.

Description:
This application claims priority to and incorporates by reference co-pending U.S. application Ser. No. 12/965,670 for Devices for Producing Sterile Therapeutic Medium filed Dec. 10, 2010. The &#39;670 application claims priority to then co-pending U.S. patent application Ser. No. 12/477,635 for Method and Apparatus for Producing Slush for Surgical Use filed Jun. 3, 2009, subsequently issued as U.S. Pat. No. 7,874,167. Through the &#39;635 application, this application claims the benefit of and incorporates by reference U.S. Provisional Application No. 61/059,732 filed Jun. 6, 2008. 
    
    
     FIELD OF THE DISCLOSURE 
     This disclosure relates generally to the production of sterile therapeutic medium such as sterile surgical slush for use in surgery. 
     BACKGROUND 
     Devices for producing sterile saline slush are known in the art. Sterile saline slush is used in a variety of surgical applications to slow organ and tissue metabolic rates thereby protecting organs from irreversible tissue damage during cardiac, neurological organ transplant, vascular, urologic and other complex surgeries. It is important that the slush has as smooth, spherical a configuration as possible to ensure atraumatic slush without sharp crystal edges that could puncture or damage human flesh or organs. The slush should have a substantially uniform consistency to maintain optimal thermodynamic cooling performance. 
     In both the surgical and non-surgical methods, slush production depends on the same basic thermodynamic phenomena. As ice grows from water that contains “impurities” the water produces a crystal matrix with the “impurities” dispersed into the interstices of the matrix. The term “impurities” are used because of the way they affect the water crystal matrix, however, they are often desirable and necessary components. In the case of non-surgical slush for drinks, the “impurities” are things like sugar and flavor mixes. In the case of surgical slush the “impurity” is salt. The impurities also provide nucleation sites that allow ice crystals to initially form. During the process of freezing a stagnant container of water with impurities, a boundary layer of slush (ice crystal in a fluid mixture) can form between a solid ice layer and a liquid water layer. 
     If during the freezing process the fluid mixture is mechanically agitated, small crystal formations are generated at the nucleation sites but size growth of the crystal matrix is inhibited because mechanical agitation prevents larger crystal growth. When these small crystals are suspended in the bulk fluid they form a slurry or slush. Mechanical agitation also helps keep the bulk fluid temperature more consistent and helps reduced large crystal growth that would otherwise occur at the fluid boundary (i.e. surface or container walls) where heat is typically being transferred out of the fluid. 
     In some prior art devices fluid is contained in a basin lined with a drape. Mechanical agitation of the fluid is provided by continually flexing the drape by lifting the drape from below with a pin or arm. The top of the basin is open to ambient air and the fluid is cooled via the metal walls and bottom that supports the drape. With this arrangement, flexing of the drape is essential to prevent large crystal formation in the fluid that is contact with the drape where heat is being transferred away from the fluid. The drape flexing also needs to be sufficient to keep the bulk mixture consistent and to keep the crystal suspended in the slush mixture. However, the need for aggressive mixing needs to be balanced with the need to maintain the integrity of the drape boundary because the drape also serves as a sterile barrier. 
     The integrity of the sterile field is very important during surgery. Any breach that might indicate that the sterile field has become contaminated is taken very seriously. A breach that is undiscovered for a period of time is especially troublesome as it is difficult to assess when the breach was created and whether it caused the patient to be exposed to contaminants while vulnerable during surgery. Thus it is no wonder that there may be grave concerns about the ongoing potential for breaches in the sterile field maintained by sterile drapes. 
     Other methods of creating slush had other shortcomings. One such method called for placing bags of sterile saline in freezers to freeze the sterile saline solution and then smashing the bag with a mallet to create slush. Such a method has a number of shortcomings including the risk of forming jagged ice crystals. 
     Another method called for the use of a frozen metal basin and chilled alcohol. This method involved pouring sterile saline inside the basin and scraping the side of the basin until sufficient slush is collected. The method produces slush, but is time consuming and resource intensive. Such a process does not scale well to provide a device that creates and maintains a significant amount sterile surgical slush. 
     SUMMARY OF THE DISCLOSURE 
     The present disclosure includes information about methods and apparatus for producing saline slush for surgical applications. Ideally, the slush produced is atraumatic slush that has been created through a process that reduces the sharp edges and produces smaller spheroid shaped pieces of slush rather than large frozen crystals. 
     One aspect of this disclosure teaches producing surgical saline slush in a rigid or semi-rigid, high integrity, sturdy container that resists punctures and leaks to better maintain a sterile barrier and does not rely on having on external object placed in the fluid to mix the slush. One type of sturdy container would be a container that could be sterilized and re-sterilized for several sterilization/use cycles. A container that is adapted for many sterilization/use cycles may be made of a durable material such as a metal. Another type of sturdy container is a pre-sterilized single use container. Such a single use container may be made of a suitable polymer to hold down costs. 
     Slush is agitated within the slush bottle. Slush bottle features are discussed which agitate and condition slush for use in medical procedures. The slush bottle may be rotated using a pair of rollers. A slush station may have one or more compartments for the production of slush and a basin shell for maintaining slush as slush in a basin. Specialized techniques for a vertical slush bottle are discussed. This summary is meant to provide an introduction to the concepts that are disclosed within the specification without being an exhaustive list of the many teachings and variations upon those teachings that are provided in the extended discussion within this disclosure. Thus, the contents of this summary should not be used to limit the scope of the claims that arise from this application. 
     Other systems, methods, features, and advantages of the disclosed teachings will be or will become apparent to one with skill in the art upon examination of the following figures and detailed description. It is intended that all such additional systems, methods, features and advantages be included within the scope of and be protected by the claims that are ultimately associated with this disclosure through the use of one or more non-provisional or non-United States patent applications that claim this disclosure as a priority document. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
       The disclosure can be better understood with reference to the following figures. The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the disclosure. Moreover, in the figures, like reference numerals designate corresponding parts throughout the different views. 
         FIG. 1 : Perspective view of a slush bottle and cap. 
         FIG. 2 : Top view of a slush bottle showing the interior. 
         FIG. 3 : View of slush production device with covers. 
         FIG. 4 : Front perspective view of device without covers. 
         FIG. 5 : Back perspective view of device without covers. 
         FIG. 6 : Side view of the slush bottle of  FIGS. 1-4 . 
         FIG. 7 : Side view of the slush bottle 90 degrees offset from  FIG. 6 . 
         FIG. 8 ; Side view of the slush bottle 90 degrees offset from  FIGS. 7  and 180 degrees offset from  FIG. 6 . 
         FIG. 9 : Side view of slush bottle 90 degrees offset from  FIG. 8 . 
         FIG. 10 : A bottom view of slush bottle shown in  FIGS. 1-10 . 
         FIG. 11  shows a flexible container of sterile saline in a slush bottle. 
         FIG. 12  shows a perspective view of slush bottle  300  with removable top  350 . 
         FIG. 13  is a side view of slush bottle  300  showing one of the two grip indents  304 , ribs  308 , and male threads  312 . 
         FIG. 14  is another side view of the slush bottle  300  showing the pair of grip indents  304 . 
         FIG. 15  shows a top view of slush bottle  300 . 
         FIG. 16  is a bottom view of slush bottle  300  showing the radial feature  316 . 
         FIG. 17  is a side view of removable top  350  with optional center paddle  360 . 
         FIG. 18  is a perspective view of removable top  350  with optional center paddle  360 . 
         FIG. 19  illustrates a slush bottle  390  that has a series of dimples  394 . 
         FIG. 20  shows only a few components from a device for the production of surgical slush to emphasize the use of a pair of rollers  404 . 
         FIG. 21  shows a high level description of the control system. 
         FIG. 22  shows a perspective view of the left side, front, and top of a slush station  500 . 
         FIG. 23  shows a front view of slush station  500  with the compartment lid for compartment  504  removed. 
         FIG. 24  is a left side view of the slush station  500  with a number of components made invisible to allow a view of interior components. 
         FIG. 25  was made by rotating  FIG. 24  slightly and made a number of additional components invisible. 
         FIG. 26  is a top front right perspective view of slush station  500  with a number of components rendered invisible to allow visualization of the relative position of other components of interest. 
         FIG. 27  shows the right side of the slush station  500  with the same components rendered invisible. 
         FIG. 28  shows the rear of the slush station  500  with the same components rendered invisible. 
         FIG. 29  is a top, right, front perspective view that shows slush station  500  with compartment  504  closed and compartment  508  open. 
         FIG. 30  is a cross section of a rotation device  700 . 
         FIG. 31  is an enlarged view of a portion of  FIG. 31  showing components of interest for the rotation of the bottle shaft  754 . 
         FIG. 32  is a view of rotational device  700  which has rotated relative to the position in  FIG. 30 . 
         FIG. 33  is a top perspective view of slush bottle  800  with center feature  804 . 
         FIG. 34  is a side view of a cross section of slush bottle  800 . 
         FIG. 35  is a top perspective view of slush bottle  830  with thread  834 . 
         FIG. 36  is a side view of slush bottle  830 . 
         FIG. 37  is a side view of a cross section of slush bottle  830 . 
         FIG. 38  is a top view of slush bottle  830 . 
         FIG. 39  is a bottom view of slush bottle  830 . 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  illustrates a slush bottle  100  with a removable cap  102 . The slush bottle  100  has a large mouth opening. The large mouth opening could be implemented with threads (not shown) for mating with corresponding threads (not shown) in the removable cap  102 . Other reversible fastening techniques known to those of skill in the art could be used. Thus, bayonet fittings, snap tops, and other fastening methods, with or without the use of a gasket could be used. Implementations that use a slush bottle oriented away from horizontal and use less liquid so that the liquid does not reach the lid may have less stringent requirements for the lid. 
     The aspect ratio and the shape of the slush bottle may come in a variety of forms. No particular expectation should be inferred from the use of the word “bottle” in lieu of a more amorphic term like container. As long as the item has an inside that can be used to receive saline and allow the removal of surgical slush, then the shape may be viable (perhaps far from optimal) as a “bottle”. 
     During operation, the slush bottle  100  is initially filled with a liquid saline solution and has the removable cap  102  tightly secured. In this context, “filled” means filled to an intended fill line rather than totally filled as having the slush bottle only partially filled is useful in promoting the tumbling action described in more detail below. 
     The slush bottle  100  and cap  102  can be made of any of a number of conventional polymers having the appropriate mechanical properties and the ability to withstand the desired sterilization regime. An example of a suitable polymer material is polypropylene. (A reusable slush bottle may have a lid that is made of the same metal as the slush bottle or at least having a similar coefficient of thermal expansion.) The saline solution that is used is conventional sterile saline solution of the type used in surgical procedures whether heated to approximately body temperature or used at some other temperature. 
     An alternative that may be used with this slush bottle or with others having an appropriate shape (see various alternative slush bottles disclosed below) is to use a sterile plastic liner for the slush bottle or lid or both. The use of a sterile plastic liner would allow a metal or other durable bottle or lid to be used with an inexpensive sterile plastic liner. The liner would need to be sufficiently durable for the task and would need to avoid having large amounts of excess liner protruding out of the bottle/lid assembly to avoid entanglement. 
     Two fins  104  (some might call them ribs) are formed into the side wall of the slush bottle  100  and protrude into the interior of the slush bottle  100 . 
       FIG. 2  shows a top view of the slush bottle  100  with interior fins  104 . The slush bottle  100  shown in  FIGS. 1 and 2  has two fins  104 ; however, one fin or more than 2 fins are also possible. While the two fins shown in  FIGS. 1 and 2  are identical, the do not have to be. The fins may optionally have one or more gaps in the fin. When using fins with at least one gap, not all fins need to have gaps and not all fins need to have the same arrangement or spacing of the gaps. As the slush bottles rotate, the gaps in the fins will cause movement of the slush through the gaps relative to the slush that is lifted by the fin and tumbled. This will add another aspect to the stirring of the slush. Likewise the fins  104  do not need to be evenly spaced around the perimeter of the slush bottle  100 . For example, the two fins  104  shown in  FIG. 2  could be spaced a hundred degrees apart rather than being 180 degrees apart. Bottles with shapes other than cylindrical (i.e. oval, square, rectangular, etc.) are also possible. 
     While the fins shown in  FIGS. 1 and 2  extend inward from the side wall, a slush bottle may optionally have one or more bottom protrusions that extend upward from the bottom of the slush bottle (toward the lid). To the extent that the protrusion is at least partially non-symmetric with the center axis of the bottom of the slush bottle, the protrusion will add another dimension to the mixing of the slush, will potentially add another surface for the falling slush to strike and may provide a way to enhance the cooling of water to form slush to the extent that cooled air is present in the protrusion extending into the slush bottle. 
     While not strictly required, it is felt that a fin that is hollow and open to the air external to the slush bottle will help cool air enter the fin and augment the cooling. A secondary benefit of the fin and a design consideration for the fins is the hollow fin may provide a finger hold for a user that is picking up a frosty slush bottle from the slush making device. The hollow fin may help the user have a reliable grip on the slush bottle while lifting, removing the cap, and pouring the slush. 
     The slush bottle geometry with at least one interior fin allows slush to be directly produced in the enclosed slush bottle interior when the slush bottle is placed in a cold enough environment and the slush bottle is agitated. Agitation could come from rotating the long axis of the slush bottle while the axis is at or near horizontal. The range of acceptable tilt angles from horizontal upward would be a function of a number of factors. Unless the bottom has one or more protrusions, it may be beneficial for the saline water to be loaded into the slush bottle so that at least some air can reach the bottom of the slush bottle so that there is some level of tumbling all the way to the bottom. The deviation from horizontal that would work would be a function of the aspect ratio of the slush bottle and the relative height of the fill line of a slush bottle relative to the height of a slush bottle when placed in a vertical position. 
     One of skill in the art will appreciate that if the slush bottle lid provided a water tight seal and the slush bottle could be retained in the slush creating device while the slush bottle is rotated that the slush bottle lid could be lower than the slush bottle bottom thus below horizontal. 
     In the configuration shown in  FIG. 1 , the fins  104  introduce mechanical agitation to the solution by carrying fluid and/or slush up the sidewall during rotation. Once the fin rotates above the horizontal plane, the fluid and/or slush the fin was carrying runs or falls back into the bulk mixture. (Note that if the fill level is above the horizontal plane the run-off for liquids may be delayed until the fin is above the waterline but slush will move relative to other slush in many instances when the fin gets above horizontal.) This agitation keeps the solution mixed and tends to promote an even temperature distribution. This agitation also breaks up larger crystal matrices to promote the creation and maintenance of a fine slush mixture (as opposed to coarse). Falling material works to breaks off crystals that form along the slush bottle interior. 
     The amount of agitation provided to the slush may be reduced if the slush bottle  100  is positioned in a vertical orientation in the slush bottle carriage (or even 180 degrees rotation from vertical). Thus in most instances the slush bottle carriage should be oriented so that the slush bottle is neither substantially vertical nor substantially upside down. 
     Having a slush bottle opening that is large relative to the cross section of the slush bottle is desirable. The large mouth opening of the slush bottle makes it easy to pour the slush out of the container. A small opening (relative to the cross section of the slush bottle) might encourage the fine, loosely packed slush to become compacted as the slush passes through a reduced cross sectional area as the slush cannot easily move from a larger cross sectional area to a smaller cross sectional area without being compacted. If the slush gets compacted, the slush tends to behave more like a solid and is therefore even harder to make the slush exit through a small opening. 
       FIG. 3  illustrates an example embodiment of a device  200  that can rotate and cool a slush bottle  100  with a cap  102  in the manner described above so as to turn the enclosed fluid saline solution into a slush mixture. While it is important that the interior of the slush bottle and the water/slush mixture remain sterile, it is not important that the outside of the slush bottle remain sterile during the chilling process. Thus, it is not important to design or maintain the device  200  so that the interior of the device remain sterile. 
     In this embodiment, the device  200  is designed to hold two slush bottles  100  that are slid into the device  200  through rotating outer rings  110 . The rotating outer rings  110  can rotate relative to the stationary outer support frame  106 . The device  200  is enclosed with a top cover  108  (also known as a housing). 
     While the device  200  can receive and chill two slush bottles  100 , devices (not shown) may be adapted receive only one slush bottle, or conversely may be adapted to receive and chill more than two slush bottles. In most instances, a device with an open cavity that allows chilled air to flow around multiple slush bottles will need to have an empty slush bottle inserted into each slush bottle hole or some sort of cover in order to reduce the loss of cold air out of an opening that does not have an inserted slush bottle. 
     An alternative would be to have separate cooling for separate compartments so that if a multi-bottle device had only one slush bottle inserted for cooling, only the compartment around that slush bottle would be cooled and the cooling going to that compartment would not travel by convection into one or more adjacent compartments that do not have a slush bottle to cool. 
     The device  200  in  FIG. 3  is shown as a stand-alone device. One of ordinary skill in the art can appreciate that this functionality may be built into a device with other functionality such as a device intended to maintain sterile fluid at an elevated temperature for use in medical procedures. See for example commonly assigned U.S. Pat. No. 7,128,275 for Liquid Warming Device with Basin or Patent Application Publication No. 2006/0289016 for Open Access Sleeve for Heated Fluid Units. 
       FIG. 4  shows the device  200  with the top cover  108  removed and with one of the slush bottles  100  withdrawn from the device  200 . One end of each of four connector rods  112  is attached to the back side of the rotating outer ring  110 . The other end of each of the four connector rods  112  is connected to the rotating bottom ring  114 . The rotating outer ring  110 , the connector rods  112 , and the rotating bottom ring  114  all rotate together and are supported by a bottom bearing  116  on one side and a front bearing  118  (shown later in  FIG. 5 ). The bottom bearing  116  is mounted in the back support plate  120  and the front bearing  118  is mounted in the outer support frame  106 . 
       FIG. 5  is a view of the device  200  from the back. The front bearing  118  described above can be seen mounted in the outer support frame  106  and holding the rotating outer ring  110 . A drive pulley  122  is attached to both rotating bottom rings  114  and to the drive motor  124 . The drive motor  124  is mounted to the back support plate  120 . A drive belt  126  is looped around the three drive pulleys  122 . Visible in this figure are some of the notches that provide access to the fasteners used to retain the individual connector rods. These details are routine to those of skill in the art and need no further discussion. 
     When the drive motor  124  is turned on it causes both rotating bottom rings  114  to rotate via the drive belt  126  and drive pulley  122 . This in-turn cause the slush bottles  100  to rotate because they are supported by the rotating bottom ring  114 , the connector rods  112 , and the rotating outer ring  110  which are being driven by the drive motor  124 . The slush bottles may be rotated at a relatively slow speed so as to facilitate the dropping of material to agitate and to minimize any centrifuge effect that would impede such agitation. Typical rotation speeds would be in the range of 10 to 30 slush bottle rotations per minute, however, a broader or shifted range of speeds may be adequate in some situations. 
     One of ordinary skill in the art will appreciate the minor modifications necessary to the device  200  to receive and rotate slush bottles with a cross section that is something other than round. One of ordinary skill in the art will recognize that other choices and arrangement of components could be made in order to effect the rotation of the slush bottles. For example the driver motor  124  could be located outside of the enclosed space. 
     The individual components of the cooling system  1004  ( FIG. 5 ) along with the interior covers and insulation are not shown in the figures because they would obscure the drive and support components. The cooling system&#39;s purpose is to provide chilled air to surround the slush bottles and to chill the air below the freezing point of the saline water within the slush bottles. The cooling system may include one or more devices such as fans to circulate the cooled air to promote the rapid cooling of the saline in the one or more bottles. Those of skill in the art will appreciate that a range of cooling systems could be used including but not limited to a standard compressor type system or a solid state Peltier cooling system. 
     The cooling system regulates the temperature around the slush bottles to within a specified range to allow slush to be produced and maintained. The control system  1008  may simply seek to maintain the air within the device at a particular target temperature that is at or slightly below the freezing point for sterile saline solution of a particular salinity. A more sophisticated system would have an initial target temperature that is well below the freezing point to expedite the initial production of slush but then have a separate maintenance temperature intended for use when the slush is ready. This maintenance temperature could be at or slightly below the freezing point (to compensate for thermal losses and energy input to the system). As the slush will continue to freeze slowly at this freezing point, it may be useful to build in a capacity for the target temperature to drift above and below the freezing point (as with a normal two temperature control scheme that results in a saw tooth temperature profile). 
     In some instances, increasing the level of agitation, perhaps by increasing the speed of slush bottle rotation may provide a wider range of temperatures that may be used to maintain the slush as slush. 
     The device  200  may optionally have a stop button to stop the rotation of the slush bottles. This stop button may make it easier to remove a slush bottle from the slush making device. 
     Additional Views of the Slush Bottle. 
       FIGS. 6-9  show the slush bottle  100  from  FIGS. 1 and 2  from four view separated by 90 degrees. 
       FIG. 6  shows a side view of the slush bottle  100  with the interior of one fin  104  visible. The portion  150  of the slush bottle that receives the cap (seen in  FIG. 1 ) is visible. 
       FIG. 7  shows a side view of the slush bottle  100  90 degrees offset from  FIG. 6 . Visible in this figure is a representation of a bottle seam  154 . The actual bottle seam may not appear as shown in  FIG. 7  and may not be readily apparent to an untrained eye. 
       FIG. 8  shows a side view of the slush bottle  100  90 degrees offset from  FIG. 7 .  FIG. 8  is identical to  FIG. 6  because this particular implementation of the slush bottle has two identical fins offset by 180 degrees. 
       FIG. 9  shows a side view of slush bottle  100  90 degrees offset from  FIG. 8 . 
       FIG. 10  shows a bottom view of slush bottle  100  including beveled rim  158  and the bottom of the representation of the bottle seam  154 . 
     Alternatives, Variations, and Extensions. 
     Cabinet Doors. 
     The slush production device  200  shown in  FIGS. 4-6  has the end of the slush bottle  100  and the slush bottle cap  102  protruding beyond openings in the device top cover  108  (also known as a housing). The slush bottle  100  and slush bottle cap  102  are thus part of the effective border that holds the chilled air within the device  200 . One of ordinary skill in the art will appreciate that the device could be modified to have a larger enclosed volume that is accessed through cabinet doors or other ready access options known in the art. Thus, the cabinet doors would form the barrier between the chilled air used for cooling and the ambient air in the hospital. Note that if the slush bottle was contained within a housing with closed cabinet doors, one could conceivably maintain a sterile state within the housing and operate the slush making device using a slush bottle without a top. Obviously the slush bottle orientation and fill level would need to be adjusted that that saline would not splash out the top during slush operation. This variation is unlikely to be widely adopted. 
     Non-Centerline Center of Rotation. 
     The slush production device  200  shown in  FIGS. 4-6  has a center of rotation for rotating the slush bottle  100  that runs through the axial centerline of the slush bottle  100 . This configuration may be preferred in some embodiments as it would tend to provide a smooth uniform agitation. Other embodiments may use a center of rotation that runs through something other than the top/bottom centerline of the slush bottle. An advantage of this choice may include a more complex agitation pattern. 
     Multi-Angled Bottle Walls. 
     One of skill in the art will recognize that a slush bottle made with severe wall joint angle changes may provide much of the agitation provided by the slush bottles with fins shown above. For example, a slush bottle with the cross section of a triangle or a five or six sided star might provide adequate agitation, particularly if the slush bottle was oriented closer to horizontal to promote slush from falling from the ridges formed by the points of the star or other appropriate shape. 
     Saline within a Flexible Bag. 
     An alternative implementation would be to place saline in a flexible container of any shape. It is probably easiest to envision a clear bag like a partially filled IV bag. Ideally the bag should not be so filled with saline as to be taut. The saline bag  190  may be placed in a slush bottle  100  as shown in  FIG. 11  and tumbled as the slush bottle rotates in the slush bottle carriage. The bag would need to be sufficiently robust, including any seams and broad pour spouts to handle the tumbling within the slush bottle which may be aligned close to horizontal. 
     One of ordinary skill in the art will recognize that in a saline bag implementation, the slush bottle need not be removable but may be integrated within the slush producing device much like the horizontal drum of a clothes dryer. 
     Alternative Slush Bottles and Removable Tops 
       FIG. 12  shows a perspective view of slush bottle  300  with removable top  350 . 
     Visible in  FIG. 12  is a pair of grip indents  304  to facilitate picking up the slush bottle  300 . The grip indents  304  may be spaced to allow a user to push squeeze the pair of grip indents  304  between the thumb and fingers of the user. The grip indents  304  may include ribs  308 . The grip indents  304  and ribs  308  serve as features in the side walls of the slush bottle  300  that serve to agitate slush while the slush bottle  300  is being rotated at any orientation and will serve to lift and drop slush if the slush bottle  300  is rotated at any orientation other than along the top/bottom axis of the slush bottle  300 . 
     A set of male threads  312  may be used to mate with corresponding threads on a removable top. Thread choice is based on providing a water tight seal but yet releasing without tools even if there is ice near the threads. 
       FIG. 12  shows a raised ridge  354  of the removable top  350 . This raised ridge  354  may be used by the user to hold the removable top  350  and to apply torque to the removable top such as would be used to thread or unthread an engagement between the removable top  350  and the slush bottle  300 . 
       FIG. 12  also shows optional center paddle  360  described in more detail below. 
       FIG. 13  is a side view of slush bottle  300  showing one of the two grip indents  304 , ribs  308 , and male threads  312 . 
       FIG. 14  is another side view of the slush bottle  300  showing the pair of grip indents  304 . 
       FIG. 15  shows a top view of slush bottle  300 . Visible in this view are grip indents  304  which extend inward and optional radial feature  316  which extends up into the slush bottle interior and provides another set of features to agitate and lift slush. In this example there are five arms to the radial feature  316  but different numbers of arms could be used. The pattern of arms does not have to be symmetric. The radial feature is an example of an agitation/lift feature on the bottom of the slush bottle  300 . The agitation/lift feature need not be a radial design. A series or parallel ribs could be used for the agitation/lift feature. As described below, there is an advantage in having an indentation at the axial centerline of the slush bottle  300  but this could be incorporated in a wide array of possible sets of agitation/lift features for the bottom of the slush bottle. 
       FIG. 16  is a bottom view of slush bottle  300  showing the radial feature  316 . 
       FIG. 17  is a side view of removable top  350  with optional center paddle  360 . While the center paddle may be configured in a number of ways, the version shown in  FIG. 17  has an outer frame with two frame sides  364  joined by a frame bottom  380 . An interior stirrer bar  368  is in the interior of the center paddle  360 . There are gaps  372  between the interior stirrer bar  368  and the two frame sides  364 . While only a single interior stirrer bar  368  is shown here, more than one can be used, especially for a particularly wide center paddle  360 . Conversely, the interior stirrer bar  368  could be omitted leaving just one gap  372  between the two frame sides  364 . The depth of the center paddle is chosen to allow clearance between the distal end of the paddle and the bottom of the slush bottle. 
     While other cross sections could be used, the cross sections for the components shown in  FIG. 17  are diamond shaped for frame sides  364  with the long dimension of the diamonds perpendicular to the long dimension of the frame bottom  380 . The cross section of the interior stirrer bar  368  is a diamond with the long dimension of the diamond parallel to the long dimension of the frame bottom  380 . An apex line  376  of the interior stirrer bar  368  is visible in  FIG. 17 . The cross section of the frame bottom  380  is triangular as best seen in the perspective view found in  FIG. 18 . 
     It is a design goal for the center paddle to agitate slush that might otherwise be immobile along the centerline of rotation. Thus a stirrer bar  368  is particularly useful along the centerline of rotation. The frame sides  364  work to break up loosely packed balls of congregated frozen slush that would otherwise tend to grow from a nucleation site. Thus, a knife-like shape to the frame sides is useful. 
     The center paddle  360  may be created as a separate piece and snapped into a corresponding connector in the interior of the raised ridge  354 . Alternatively, the center paddle  360  and the removable top  350  may be molded as one piece. 
     Addition of Minor Wall Features 
       FIG. 19  illustrates a slush bottle  390  that is much like slush bottle  300  but has the addition of a series of dimples  394 . A range of different dimple shapes and dimple array patterns could be used but the dimple should be convex as viewed from the interior of the slush bottle so that the dimple provides additional agitation to prevent localized areas of stagnant fluid. Since all cooling occurs through the bottle walls, if there are any stagnant or low circulation regions along the walls, those areas will freeze first. The minor wall feature geometries will likely be small dimples as shown here, ribs, or analogous structures; basically anything that can cause a disruption to the boundary layer of fluid next to the wall. A concave dimple (as viewed from the interior of the slush bottle  390 ) would be prone to having ice form and collect in the cavity of the dimple. 
     Alternative Way of Rotating the Slush Bottle 
       FIG. 20  shows only a few components from a device for the production of surgical slush. The other components have been rendered invisible to isolate the components relevant to this teaching. 
     The disclosure set forth above shows how to rotate a slush bottle by placing the slush bottle into a slush bottle carriage and then rotating the slush bottle carriage and thus the slush bottle. An alternative is to place the slush bottle between two rollers and then rotate one or more of the rollers to cause the slush bottle to rotate. 
       FIG. 20  shows slush bottle  300  with removable top  350 . A pair of rollers  404  (shown here as transparent to allow the bottle to be seen) and a centerline probe  412  holds the slush bottle  300  with removable top  350  in position as the pair of rollers  404  is inclined with respect to horizontal. 
     The angle of the centerline of the slush bottle relative to horizontal may be 20 or 30 degrees which balances the desire to have gravity maintain contact of the bottle bottom with the centerline probe  412  while avoiding problems in having the rollers  404  roll the slush bottle  300  which becomes more difficult as the deviation from horizontal becomes more severe. 
     A tilted slush bottle will tend to keep slush at the centerline to provide a temperature indication of the slush to the centerline probe better than a horizontal orientation as a tilted orientation will shift slush toward the centerline when the slush bottle is less than half filled with saline and slush. 
     The use of a threaded engagement between the slush bottle  300  and the removable top  350  allows for a water tight seal of the slush bottle  300 . 
     Centerline probe  412  monitors the temperature of the exterior of the slush bottle  300  for use with a control system for the device for making slush. Placing the probe at the centerline of rotation of the slush bottle  300  allows for consistent monitoring of one place on the slush bottle  300  rather than a ring of locations. The temperature probe used with the centerline probe  412  is apt to be a metal like stainless steel and thus not likely to wear from contact with the plastic bottle. Spinning the bottom exterior of the slush bottle  300  against the temperature probe helps maintain intimate contact by avoiding ice buildup between the bottom of the slush bottle and the centerline probe  412 . Those of skill in the art can choose a temperature monitoring device such as a thermocouple, thermistor, RTD (Resistance Temperature Detection), or other appropriate device. 
     A set of four bushings  408  is shown to indicate that in this embodiment the rollers  404  pass through the walls in the chilled area. The drive mechanism for rotating one or both of the pairs of rollers  404  can be any suitable drive mechanism. The drive mechanism may be connected to the end  416  of one or both rollers  404 . Driving both rollers  404  may be more reliable as there may be a build-up of frost on the bottle exterior which may cause slippage and using the slush bottle  300  to cause the non-driven roller to rotate adds resistance that the one driven roller must overcome. A simple motor driven belt turning pulleys on the end of each of the two rollers  404  for a given slush bottle  300  is one solution. Those of skill in the art can implement many different arrangements for driving the rollers  404 . 
     While the rollers  404  may be driven in one direction at a fixed speed other non-uniform patterns may be advantageous. One option is to repeatedly follow a cycle of A) driving the rollers  404  clockwise for a period of time; B) ceasing driving the rollers  404 ; C) driving the rollers  404  counter-clockwise for a period of time; and D) ceasing driving counter-clockwise. Another option is to always drive the rollers  404  in the same direction but periodically alter the speed of rotation. 
       FIG. 21  shows a high level description of the control system. Control system  1008  controls the overall cooling of the device interior via cooling system  1004 . Control system  1008  works with the cooling unit  1004  to cool a sink chamber of chilled air adjacent to the compartment  420  to a temperature well below what is needed for use in compartment  420 . The control system uses sink chamber temperature sensor  494 . This chamber may be augmented with a metal block or analogous item to add thermal mass so that the reservoir of chilled air is more than sufficient to continue to act as a heat sink even as the refrigeration equipment (not shown here) goes through a normal defrost cycle and stops providing cooling temporarily. Thus, the temperature for the chamber air may be targeted to negative 25 degrees Fahrenheit though the temperature used for sustained chilling of the slush bottle  300  may be in the range of negative 8 degrees Fahrenheit. 
     Control system  1008  is in communication with centerline probe  412  and optionally one or more compartment temperature sensors  498  for compartment  420  (shown here with compartment lid removed). Control system  1008  controls drive system  1012  which may drive both rather than just one roller  404 . Above the right roller  404  is a series of one or more drive fans  424  which drive cold air into compartment  420 . Air exits the compartment via vents  436  (see  FIG. 23 ) to the left of the left roller. 
     Continuing with  FIG. 21 , a number of circulation fans  428  suspended above the floor of the compartment  420  by fan bracket  432  are controlled by the control system  1008 . When door open indicator  490  indicates that the lid covering the compartment  420  has been lifted, the control system  1008  may turn off the drive fan  424  to avoid sending more cold air to an open compartment and turn off circulation fans  428  so that the cold air in the compartment  420  settles downward to be largely retained by the compartments vertical walls. 
     The control system  1008  may monitor the compartment  420  air temperature and the bottle surface temperature to get an indication of the liquid/slush temperature. As the reading from the centerline probe  412  will be impacted by both the temperature of the slush bottle bottom and the temperature of the compartment air, the estimated temperature of the slush bottle interior is a function of the temperature readings at  412  and  498 . The control system can respond to a relatively high temperature estimate for the slush bottle interior to aggressively drop the air temperature in the compartment  420  around the slush bottle  300  to accelerate cooling to near the temperature for freezing the saline and then allow the temperature to rise to closer to the freezing temperature. Thus, the compartment may be aggressively chilled then allowed to rise to approximately negative 8 degrees Fahrenheit. 
     Slush Station 
       FIG. 22  shows a perspective view of the left side, front, and top of a slush station  500 . This slush station has two slush making compartments  504  and  508 . Each slush making compartment has a compartment lid  512 . Preferably, the lid is at least partially translucent so a user can see whether the compartment has a slush bottle  300 . The compartment lid for slush compartment  504  is omitted here so that lid hinge  520  and other components can be seen without distraction from the edges of the compartment lid. 
     Use of a compartment lid  512  so that the slush bottle  300  is totally enclosed reduces the amount of condensation to be handled by the cooling system and reduces the ingress of heat from ambient air. 
     On top of the slush station  500  is a basin shell  516  that may receive a slush basin for holding surgical slush being used by the operating room personnel. (The top cover  524  of the slush station is shown as transparent to help show detail.) A drape may be placed to surround the metal basin shell  516  to isolate the upper part of the slush station from the sterile field. The lower part of the slush station would not be part of the sterile field although the interior of the slush bottle  300  would be maintained as sterile. Alternatively, a drape that is fitted to the shape of the basin shell  516  may be placed over the slush station  500  including the basin shell  516 . As the basin shell  516  acts as a heat sink for a corresponding inserted basin (not shown), a conforming fit for the drape, basin shell  516 , and basin is desirable. 
       FIG. 23  shows a front view of slush station  500  with the compartment lid for compartment  504  removed. Visible in this view are compartment lid  512 , compartments  504  and  508 , circulations fans  428 , drive fans  424 , and air vents  436 . 
       FIG. 24  is a left side view of the slush station  500  with a number of components made invisible to allow a view of interior components. Wiring connections and various components to capture and channel condensation, and other miscellaneous conventional items not needed to convey the teachings of this disclosure are not shown. These views to show internal components provide an example of how the major components might be placed in the housing. 
     From this view, one can see basin shell  516 , sink chamber top  528 , fan  552 , evaporator  532 , hinge  520 , raised ridge  354  of removable top  350 , compartment lid  512  for the compartment  504 , roller  404  (drive mechanism not shown), drive fans  424 , circulation fans  428 , bottle insulator shield  556 , condenser  536 , refrigerant filter  560 , compressor pressure switch  544 , compressor start capacitor  564 , compressor control junction box  568 , compressor  572 , accumulator  624 , and condensate collection pan  576  (made invisible in other views). Basin chamber fan  580  is actually located in the foreground relative to basin shell  516  and there is a corresponding basin chamber vent  592  (not visible here) on the opposite side of basin shell  516 . While there are a number of insulated areas, in order to understand the air circulation it is useful to include front insulation  584  and rear insulation  588 . 
       FIG. 25  was made by rotating  FIG. 24  slightly and made a number of additional components invisible.  FIG. 25  is useful to show the four major air chambers and their air flow patterns. The first chamber is the sink chamber  604 . This chamber is chilled by the refrigeration system to provide a significant ability to act as a heat sink for other chambers even when the refrigeration equipment is not currently cooling the sink chamber  604  as the equipment is going through a defrost cycle. The sink chamber  604  may have metal or some other material added to the sink chamber  604  to increase the thermal mass of the sink chamber  604 . The sink chamber  604  is chilled possibly to the range of negative 25 degrees Fahrenheit by blowing air up through fan  552  and down through the evaporator  532  which is not a box as shown here but is a heat exchanger. 
     The basin chamber  608  is above the sink chamber  604  and receives cold air from the sink chamber  604  via the basin chamber fan  580  which is controlled by the control system to drive the temperature of the basin chamber  608  to a desired set point to allow the thermally conductive basin shell  516  to draw heat from a slush mixture in a basin to offset the heat ingress to the slush from the ambient air of the surgical room. Driving air into the basin chamber  608  causes airflow through vent  592  as represented by the arrow. The control system may be set to maintain a temperature of about zero degrees Fahrenheit in basin chamber  608  but this number may be set to a different temperature depending on the ambient air temperature of the surgery room, and the heat transfer characteristics of the slush station  500 . 
     Slush making compartment  504  receives chilled air from sink chamber  604  by operation of drive fans  424 . The drive fans  424  are controlled by the control system to achieve a desired temperature of the air in the slush making compartment  504 . Warmer air is returned through air vents  436  to the sink chamber  604 . 
     Slush making compartment  508  is separately controlled but operates in an analogous way to slush making compartment  504 . 
     Continuing with  FIG. 25 , equipment cavity  612  contains the compressor  572  and other equipment. This equipment gives off heat and thus equipment cavity  612  is separated from the adjacent sink chamber  604  and the slush making compartments  504  and  508 . 
       FIG. 26  is a top front right perspective view of slush station  500  with a number of components rendered invisible to allow visualization of the relative position of other components of interest. As the slush bottle for compartment  504  has been made invisible except for removable top  350  (shown here in an embodiment without a center paddle). Vents  436 , lid hinges  520 , and rollers  404  are visible. Starting from the top of the slush station  500 , the visible components are the basin shell  516 , top insulation  620 , sink chamber top  528 , basin chamber vent  592 , evaporator air guide  548 , evaporator  532  (shown as a box rather than with all the details of a heat exchanger), condenser  536 , receiver  540 , and compressor pressure switch  544 . The basin shell  516  is made of metal or some other material that has high thermal conductivity to serve as a heat sink to draw off heat from a correspondingly sized basin (possibly made of a polymer) that is placed into the basin shell  516 . As noted above, slush added to the inserted basin would be maintained as slush as the chilled basin shell  516  would counteract the heat ingress to the slush from the ambient air. 
       FIG. 27  shows the right side of the slush station  500  with the same components rendered invisible. From this view, one can see basin shell  516 , sink chamber top  528 , fan  552 , evaporator  532 , hinges  520  for the two compartment lids (one up and one down but both invisible), raised ridge  354  of removable top  350 , roller  404  (drive mechanism not shown), drive fans  424 , circulation fans  428 , bottle insulator shield  556 , condenser  536 , refrigerant filter  560 , receiver  540 , compressor pressure switch  544 , compressor start capacitor  564 , and compressor control junction box  568 . Also visible are rear insulation  588 , top insulation  620 , and basin chamber fan  580 . 
       FIG. 28  shows the rear of the slush station  500  with the same components rendered invisible. From this view, one can see basin shell  516 , sink chamber top  528 , evaporator air guide  548 , three fans  552  (not to scale), drive fans  424 , air vents  436 , bottle insulator shield  556 , condenser  536 , receiver  540 , compressor start capacitor  564 , compressor control junction box  568 , and compressor  572 . Also visible in  FIG. 28  are top insulation  620  and basin chamber fan  580 . 
       FIG. 29  is a top, right, front perspective view that shows slush station  500  with compartment  504  closed and compartment  508  open.  FIG. 29  includes optional casters  630 . 
     Vertical Orientation of the Slush Bottle 
     The disclosure set forth above notes that it is useful to orient the slush bottle in some orientation other than vertical or upside down in order to promote the lifting of slush to allow the falling of the slush to condition the slush to form atraumatic slush. The teachings of the present disclosure may be extended to include devices for the production of sterile slush if one or more of the following are adapted. 
     Complex Rotational Motion 
     Mixing could be performed by spinning the slush bottle about its axis while also orbiting the slush bottle about an axis that is not aligned with the bottle axis. This complex movement would cause slush to be pressed against a portion of the wall for a moment and then fall. Even the slush that was below the water level of the slush/saline slurry would impact the side walls to condition the slush to form atraumatic slush without large crystalline structures. One suitable device for this complex rotational motion is shown in  FIG. 30 . 
       FIG. 30  is shown in cross section to allow the differences between bushings and sleeves to be highlighted. 
     Rotation device  700  has two rotating shafts: bottle shaft  754  and orbital shaft  728 . The bottle shaft  754  is driven to rotate slush bottle  300  around the slush bottle&#39;s longitudinal axis as indicated by arrow  758 . A second rotation  740  occurs around orbital shaft  728 . The second rotation causes bottle shaft  754  to rotate around orbital shaft  728 . 
     Orbital motor  704  mounted on plate  708  drives motor shaft  712 . Motor shaft  712  drives pulley  716  which in turn drives pulley  724  by belt  720 . Pulley  724  drives orbital shaft  728  which passes through plate  708  via bushing  732 . Rotating orbital shaft  728  rotates upper plate  736 . Ignoring for now the potential for bottle shaft  754  to rotate, the rotation of orbital shaft  728  rotates bottle shaft  754  and bottle platform  790  including retention poles  794  which hold the slush bottle  300 . Compare  FIG. 30  to  FIG. 32  which shows bottle shaft  754  between orbital shaft  728  and orbital motor  704 . 
       FIG. 31  shows a segment of  FIG. 30  enlarged to allow labeling of components of interest for the rotation of the bottle shaft  754 . Bottle motor  750  drives motor shaft  758  which drives pulley  762 . Pulley  762  drives pulley  770  via belt  766 . Pulley  770  drives pulley  774  via sleeve  778 . Pulley  774  drives pulley  782  via belt  786 . Pulley  782  rotates bottle platform  790  around shaft  754  which passes through upper plate  736  via bushing  798 . 
     The spinning device of  FIGS. 30-32  can implement a range of complex motion for a slush bottle  300 . This motion could be further complicated by moving the centerline of the slush bottle  300  away from the centerline of bottle shaft  754 . Another alternative would be to adjust the spinning of the slush bottle  300  relative to the spinning around orbital shaft  728  to establish a vortex within the slurry in the slush bottle  300 . 
       FIGS. 33 and 34  show a slush bottle  800  that may be used in a vertical orientation. The slush bottle  800  has center feature  804  with a set of ribs  808 . Rotating the slush bottle  800  back and forth with a rotation of about 45 to 90 degrees will tend to push slush radially outward from the lower ends of the ribs  808 . The radial outward movement of slush along the bottom  812  the slush bottle  800  will tend to push slush up the outer walls  816  as shown by the arrows in the cross section view of  FIG. 34 . As slush is moved up the outer walls  816  it will move back to the center. This agitated slurry of migrating slush will tend to retard the growth of loose aggregation of slush into slush balls and the formation of larger crystals of ice. 
     A slush bottle could be implemented with a large thread structure on a central core. This slush bottle could be rotated in a clockwise direction and the screw structure would tend to move slush up the central region of the slush bottle and down the side walls to agitate and circulate the slush. Periodically the slush bottle could be moved in a counterclockwise motion to cause the screw like effect from the central core to be reversed and thus move the slush in the opposite direction at the central core and at the side walls. The central core could extend from the slush bottle bottom, the removable top, or both. The proportion of the movement in the clockwise direction to counter-clockwise could be equal but it would not have to be. 
       FIGS. 35-39  show views of slush bottle  830 . Slush bottle  830  has a thread  834  along the outer wall of the slush bottle  830 . Rotating slush bottle  830  in one direction, even when the slush bottle  830  is in a vertical orientation will move slush toward the removable top (not shown). As slush moves up the walls toward the removable top, slush already near the top will be drawn down the centerline of the slush bottle  830  toward the bottom  838  of the slush bottle  830 . Reversing the direction of rotation would reverse that pattern. Rotating an open slush bottle  830  could be used to dispense a finite amount of slush as the rotating bottle acts to advance the slush out to the removable top. 
     For a number of the examples given above, the movement of the slush bottle could be augmented by simultaneously or intermittently moving the slush bottle in the vertical direction to help with vertical movement of the slush relative to the bottle walls. 
     One of skill in the art will recognize that some of the alternative implementations set forth above are not universally mutually exclusive and that in some cases additional implementations can be created that employ aspects of two or more of the variations described above. Likewise, the present disclosure is not limited to the specific examples or particular embodiments provided to promote understanding of the various teachings of the present disclosure. Moreover, the scope of the claims which follow covers the range of variations, modifications, and substitutes for the components described herein as would be known to those of skill in the art.