Patent Publication Number: US-2019192339-A1

Title: Thermal system with graphical user interface

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to U.S. provisional patent application Ser. No. 62/610,362 filed Dec. 26, 2017, by inventor Gregory S. Taylor and entitled THERMAL SYSTEM WITH GRAPHICAL USER INTERFACE, the complete disclosure of which is incorporated herein by reference. 
    
    
     BACKGROUND 
     The present disclosure relates to a thermal control system for controlling the temperature of circulating fluid that is delivered to one or more thermal pads positioned in contact with a patient. 
     Thermal control systems are known in the art for controlling the temperature of a patient by providing a thermal control unit that supplies temperature-controlled fluid to one or more thermal pads or catheters positioned in contact with a patient. The thermal control unit includes one or more heat exchangers for controlling the temperature of the fluid and a pump that pumps the temperature-controlled fluid to the pad(s) and/or catheter. After passing through the pad(s) and/or catheter, the fluid is returned to the thermal control unit where any necessary adjustments to the temperature of the returning fluid are made before being pumped back to the pad(s) and/or catheter. In some instances, the temperature of the fluid is controlled to a static target temperature, while in other instances the temperature of the fluid is varied as necessary in order to automatically effectuate a target patient temperature. 
     Thermal control units typically include a user interface adapted to allow the user to input information for using the thermal control unit, as well as for displaying information useful to the user of the thermal control unit. 
     SUMMARY 
     The present disclosure is directed to an improved thermal control unit that improves upon the user interface in one or more manners, including, but not limited to, displaying thermal therapy treatment information in a more concise and integrated fashion, allowing users to achieve easier and greater control over the thermal control unit, controlling the thermal therapy device with a greater degree of granularity, and providing zone-specific information to the user. Still other improved aspects of the thermal control system disclosed herein will be apparent to those skilled in the art in light of the following written description. 
     According to one embodiment of the present disclosure a thermal control unit is provided for controlling a patient&#39;s temperature that includes a fluid outlet, a fluid inlet, a pump, a heat exchanger, a fluid temperature sensor, a patient temperature sensor port, a controller, and a user interface. The fluid outlet couples to a fluid supply line and the fluid inlet couples to a fluid return line. The circulation channel fluidly couples the fluid outlet and the fluid inlet. The pump circulates the fluid through the circulation channel from the fluid inlet to the fluid outlet. The heat exchanger adds or removes heat from the fluid circulating in the circulation channel. The patient temperature sensor port is adapted receive patient temperature readings from a patient temperature sensor. The controller controls the heat exchanger in order to control the patient&#39;s temperature, and the user interface is adapted to display patient temperature readings on a graph having a time axis and a temperature axis. The user interface is also adapted to display an event icon on the graph. The event icon corresponds to an event occurring at an event time and is related to the thermal therapy. The event icon is displayed at a position on the graph along the time axis that corresponds to the event time. 
     According to other aspects of the present disclosure, the user interface includes a touch screen display and both the event icon and the graph are displayed on the touch screen display. 
     In some embodiments, the user interface is adapted to provide further information about the event when the event icon is touched by a user. The event may be one or more of the following: a medication delivered to the patient; a detection of patient shivering; a sedation of the patient; a changing of a thermal pad coupled to the fluid supply line and fluid return line; an adjustment of a thermal pad coupled to the fluid supply line and fluid return line; a change in location of the patient temperature sensor; a flushing of the patient&#39;s body adjacent the patient temperature sensor; a performance of maintenance on the thermal control unit; an error detected by the controller; an alert issued by the controller; and/or another type of event. 
     In some instances, the controller detects an occurrence of the event and automatically displays the event icon on the graph after detecting the event occurrence, while in other instances the user interface displays the event icon on the graph in response to a user manually entering information regarding the event via the user interface. 
     When manually entering event information, the user interface may be adapted to allow a user to enter the event time by touching a position along the time axis corresponding to the event time. 
     The user interface is also adapted to display a plurality of event icons on the graph, each event icon being displayed at a position along the time axis corresponding to the time of the underlying event associated with the event icon. 
     Additional information may also be displayed on the graph, such as, but not limited to, fluid temperature readings from the fluid temperature sensor, a patient target temperature, a heart rate of the patient, a respiration rate of the patient, a potassium level of the patient, a blood pressure of the patient, and/or other information. 
     In some embodiments, the user interface is adapted to allow a user to touch a first location on the graph along the temperature axis to set a maximum temperature of the fluid, and to touch a second location along the temperature axis to set a minimum temperature of the fluid. The controller controls the heat exchanger such that a temperature of the circulating fluid does not exceed the maximum and minimum temperatures. 
     The thermal control unit, in some embodiments, includes a user interface having a filter control that, when selected, filters one or more selected event icons such that the user interface does not display any filtered event icons. 
     According to another embodiment of the present disclosure, a thermal control unit for controlling a patient&#39;s temperature during thermal therapy is provided. The thermal control unit includes a fluid outlet, a fluid inlet, a pump, a heat exchanger, a fluid temperature sensor, a patient temperature sensor port, a controller, and a user interface. The fluid outlet couples to a fluid supply line and the fluid inlet couples to a fluid return line. The circulation channel fluidly couples the fluid outlet and the fluid inlet. The pump circulates the fluid through the circulation channel from the fluid inlet to the fluid outlet. The heat exchanger adds or removes heat from the fluid circulating in the circulation channel. The patient temperature sensor port is adapted receive patient temperature readings from a patient temperature sensor. The controller controls the heat exchanger in order to control the patient&#39;s temperature, and the user interface is adapted to display patient temperature readings on a graph having a time axis and a temperature axis. The user interface is further adapted to allow a user to touch a first location on the graph along the temperature axis to set a maximum permissible temperature of the fluid, and to touch a second location along the temperature axis to set a minimum permissible temperature of the fluid. The controller controls the heat exchanger such that a temperature of the circulating fluid does not exceed the maximum and minimum permissible temperatures. 
     According to other aspects, the user interface is further adapted to determine a first time on the time axis corresponding to the first location and a second time on the time axis corresponding to the second location. Thereafter, the controller controls the heat exchanger such that the temperature of the circulating fluid does not exceed the maximum permissible temperature at the first time and does not exceed the minimum temperature at the second time. 
     In some embodiments, the user interface is adapted to allow a user to draw a first line on the graph defining a plurality of maximum temperatures at a first plurality of times, and to draw a second line on the graph defining a plurality of minimum temperatures at a second plurality of times. The controller then controls the heat exchanger such that the temperature of the circulating fluid does not exceed the plurality of maximum temperatures at the first plurality of times and does not exceed the plurality of minimum temperatures at the second plurality of times. 
     The user interface is further adapted, in some embodiments, to allow a user to touch a third location on the graph along the temperature axis to set a target temperature for the patient. 
     In some embodiments, the user interface is further adapted to allow a user to draw a first line on the graph defining a plurality of patient target temperatures at a plurality of times. In response, the controller controls the heat exchanger such that the temperature of the patient is controlled to match the plurality of patient target temperatures at the plurality of times. 
     According to another embodiment of the present disclosure, a thermal control unit for controlling a patient&#39;s temperature during thermal therapy is provided. The thermal control unit includes first and second fluid inlets and first and second fluid outlets, a circulation channel, a pump, a heat exchanger, a first inlet fluid temperature sensor, a second inlet fluid temperature sensor, an outlet fluid temperature sensor, a controller, and a user interface. The first fluid outlet and first fluid inlet are adapted to supply and receive, respectively, temperature-controlled fluid for a first zone of a patient&#39;s body. The second fluid outlet and second fluid inlet are adapted to supply and receive, respectively, temperature-controlled fluid for a second zone of a patient&#39;s body. The circulation channel fluidly couples the first and second fluid inlets to the first and second fluid outlets. The pump circulates fluid through the circulation channel from the first and second fluid inlets to the first and second fluid outlets. The heat exchanger adds or removes heat from the fluid circulating in the circulation channel. The first and second inlet temperature sensors sense temperatures of the fluid returning from the first and second fluid inlets, respectively. The controller controls the heat exchanger in order to control the patient&#39;s temperature. The user interface is adapted to display a first set of information relating to the patient&#39;s first zone and a second set of information relating to the patient&#39;s second zone. 
     According to other aspects, the first set of information includes information derived from the first inlet fluid temperature sensor and the second set of information includes information derived from the second inlet fluid temperature sensor. 
     The user interface may also be adapted to display an image of a human body and locations of the first and second zones on the human body image. When the user interface includes a touch screen, the user interface is adapted to display the first set of information when a user touches the first zone of the human body image on the touch screen and to display the second set of information when the user touches the second zone of the human body image on the touch screen. 
     In some embodiments, the first set of information includes an indication of a first amount of heat transfer to or from the patient&#39;s first zone, and the second set of information includes an indication of a second amount of heat transfer to or from the patient&#39;s second zone. 
     The thermal control unit may further comprise a first patient temperature sensor port adapted to receive patient temperature readings from a first patient temperature sensor positioned in the first zone and a second patient temperature sensor port adapted to receive patient temperature readings from a second patient temperature sensor positioned in the second zone. The first set of information includes information derived from the first patient temperature sensor and the second set of information includes information derived from the second patient temperature sensor. 
     In some embodiments, the user interface is adapted to display first patient temperature readings from the first patient temperature sensor on a first graph having a first time axis and a first temperature axis, and to display second patient temperature readings from the second patient temperature sensor on a second graph having a second time axis and a second temperature axis. 
     When a touch screen is included, the user interface may be adapted to allow a user to control a first thermal therapy parameter associated with the first zone by touching on the first zone of the human body image, and to allow a user to control a second thermal therapy parameter associated with the second zone by touching on the second zone of the human body image. In some embodiments, the first thermal therapy parameter is a limit on a temperature of the fluid delivered to the first zone of the patient&#39;s body and the second thermal therapy parameter is a limit on a temperature of the fluid delivered to the second zone of the patient&#39;s body. Other parameters may also be controlled via the touch screen. 
     Before the various embodiments disclosed herein are explained in detail, it is to be understood that the claims are not to be limited to the details of operation or to the details of construction, nor to the arrangement of the components set forth in the following description or illustrated in the drawings. The embodiments described herein are 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 claims to any specific order or number of components. Nor should the use of enumeration be construed as excluding from the scope of the claims any additional steps or components that might be combined with or into the enumerated steps or components. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a thermal control system according to one aspect of the present disclosure shown applied to a patient on a patient support apparatus; 
         FIG. 2  is a perspective view of a thermal control unit of the thermal control system of  FIG. 1 ; 
         FIG. 3  is a block diagram of a first embodiment of the thermal control system of  FIG. 1 ; 
         FIG. 4  is an illustrative graph displayable on a user interface of the thermal control unit showing a patient&#39;s actual temperature, the patient&#39;s target temperature, and a plurality of events; 
         FIG. 5  is another illustrative graph displayable on the user interface of the thermal control unit showing a patient&#39;s actual temperature, the patient&#39;s target temperature, and a plurality of events; 
         FIG. 6  is the graph of  FIG. 5  displayed after a user has activated a filter function for certain patient events; 
         FIG. 7  is another illustrative graph displayable on the user interface of the thermal control unit showing a patient&#39;s progress during a thermal therapy session, as well as a user-selectable control box; 
         FIG. 8  is another illustrative graph displayable on the user interface of the thermal control unit showing maximum and minimum permissible fluid temperatures selectable by a user; 
         FIG. 9  is a block diagram of an alternative embodiment of a thermal control system according to another aspect of the present disclosure; and 
         FIG. 10  is an illustrative graphic displayable on the user interface of the thermal control unit of  FIG. 10  showing a human body image with multiple zones, including a set of information pertaining to each of the zones. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     A thermal control system  20  according to one embodiment of the present disclosure is shown in  FIG. 1 . Thermal control system  20  is adapted to control the temperature of a patient  28 , which may involve raising, lowering, and/or maintaining the patient&#39;s temperature. Thermal control system  20  includes a thermal control unit  22  coupled to one or more thermal therapy devices  24 . The thermal therapy devices  24  are illustrated in  FIG. 1  to be thermal pads, but it will be understood that thermal therapy devices  24  may take on other forms, such as, but not limited to, blankets, vests, patches, caps, catheters, or other structures that receive temperature-controlled fluid. For purposes of the following written description, thermal therapy devices  24  will be referred to as thermal pads  24 , but it will be understood by those skilled in the art that this terminology is used merely for convenience and that the phrase “thermal pad” is intended to cover all of the different variations of thermal therapy devices  24  mentioned above (e.g. blankets, vests, patches, caps, catheters, etc.) and variations thereof. 
     Thermal control unit  22  is coupled to thermal pads  24  via a plurality of hoses  26 . Thermal control unit  22  delivers temperature-controlled fluid (such as, but not limited to, water or a water mixture) to the thermal pads  24  via the fluid supply hoses  26   a.  After the temperature-controlled fluid has passed through thermal pads  24 , thermal control unit  22  receives the temperature-controlled fluid back from thermal pads  24  via the return hoses  26   b.    
     In the embodiment of thermal control system  20  shown in  FIG. 1 , three thermal pads  24  are used in the treatment of patient  28 . A first thermal pad  24  is wrapped around a patient&#39;s torso, while second and third thermal pads  24  are wrapped, respectively, around the patient&#39;s right and left legs. Other configurations can be used and different numbers of thermal pads  24  may be used with thermal control unit  22 , depending upon the number of inlet and outlet ports that are included with thermal control unit  22 . By controlling the temperature of the fluid delivered to thermal pads  24  via supply hoses  26   a,  the temperature of the patient  28  can be controlled via the close contact of the pads  24  with the patient  28  and the resultant heat transfer therebetween. 
     As shown more clearly in  FIG. 2 , thermal control unit  22  includes a main body  30  to which a removable reservoir  32  may be coupled and uncoupled. Removable reservoir  32  is configured to hold the fluid that is to be circulated through thermal control unit  22  and the one or more thermal pads  24 . By being removable from thermal control unit  22 , reservoir  32  can be easily carried to a sink or faucet for filling and/or dumping of the water or other fluid. This allows users of thermal control system  20  to more easily fill thermal control unit  22  prior to its use, as well as to drain thermal control unit  22  after use. 
     As shown in  FIG. 3 , thermal control unit  22  includes a pump  34  for circulating fluid through a circulation channel  36 . Pump  34 , when activated, circulates the fluid through circulation channel  36  in the direction of arrows  38  (clockwise in  FIG. 3 ). Starting at pump  34  the circulating fluid first passes through a heat exchanger  40  that adjusts, as necessary, the temperature of the circulating fluid. Heat exchanger  40  may take on a variety of different forms. In some embodiments, heat exchanger  40  is a thermoelectric heater and cooler. In the embodiment shown in  FIG. 3 , heat exchanger  40  includes a chiller  42  and a heater  44 . Further, in the embodiment shown in  FIG. 3 , chiller  42  is a conventional vapor-compression refrigeration unit having a compressor  46 , a condenser  48 , an evaporator  50 , an expansion valve (not shown), and a fan  52  for removing heat from the compressor  46 . Other types of chillers and/or heaters may be used. 
     After passing through heat exchanger  40 , the circulating fluid is delivered to an outlet manifold  54  having an outlet temperature sensor  56  and a plurality of outlet ports  58 . Temperature sensor  56  is adapted to detect a temperature of the fluid inside of outlet manifold  54  and report it to a controller  60 . Outlet ports  58  are coupled to supply hoses  26   a.  Supply hoses  26   a  are coupled, in turn, to thermal pads  24  and deliver temperature-controlled fluid to the thermal pads  24 . The temperature-controlled fluid, after passing through the thermal pads  24 , is returned to thermal control unit  22  via return hoses  26   b.  Return hoses  26   b  couple to a plurality of inlet ports  62 . Inlet ports  62  are fluidly coupled to an inlet manifold  78  inside of thermal control unit  22 . 
     Thermal control unit  22  also includes a bypass line  64  fluidly coupled to outlet manifold  54  and inlet manifold  78  ( FIG. 3 ). Bypass line  64  allows fluid to circulate through circulation channel  36  even in the absence of any thermal pads  24  or hoses  26   a  being coupled to any of outlet ports  58 . In the illustrated embodiment, bypass line  64  includes an optional filter  66  that is adapted to filter the circulating fluid. If included, filter  66  may be a particle filter adapted to filter out particles within the circulating fluid that exceed a size threshold, or filter  66  may be a biological filter adapted to purify or sanitize the circulating fluid, or it may be a combination of both. In some embodiments, filter  66  is constructed and/or positioned within thermal control unit  22  in any of the manners disclosed in commonly assigned U.S. patent application Ser. No. 62/404,676 filed Oct. 11, 2016, by inventors Marko Kostic et al. and entitled THERMAL CONTROL SYSTEM, the complete disclosure of which is incorporated herein by reference. 
     The flow of fluid through bypass line  64  is controllable by way of a bypass valve  68  positioned at the intersection of bypass line  64  and outlet manifold  54  ( FIG. 3 ). When open, bypass valve  68  allows fluid to flow through circulation channel  36  to outlet manifold  54 , and from outlet manifold  54  to the connected thermal pads  24 . When closed, bypass valve  68  stops fluid from flowing to outlet manifold  54  (and thermal pads  24 ) and instead diverts the fluid flow along bypass line  64 . In some embodiments, bypass valve  68  may be controllable such that selective portions of the fluid are directed to outlet manifold  54  and along bypass line  64 . In some embodiments, bypass valve  68  is controlled in any of the manners discussed in commonly assigned U.S. patent application Ser. No. 62/610,319, filed Dec. 26, 2017, by inventors Gregory Taylor et al. and entitled THERMAL SYSTEM WITH OVERSHOOT REDUCTION, the complete disclosure of which is incorporated herein by reference. 
     The incoming fluid flowing into inlet manifold  78  from inlet ports  62  and/or bypass line  64  travels back toward pump  34  and into an air remover  70 . Air remover  70  includes any structure in which the flow of fluid slows down sufficiently to allow air bubbles contained within the circulating fluid to float upwardly and escape to the ambient surroundings. In some embodiments, air remover  70  is constructed in accordance with any of the configurations disclosed in commonly assigned U.S. patent application Ser. No. 15/646,847 filed Jul. 11, 2017, by inventor Gregory S. Taylor and entitled THERMAL CONTROL SYSTEM, the complete disclosure of which is hereby incorporated herein by reference. After passing through air remover  70 , the circulating fluid flows past a valve  72  positioned beneath fluid reservoir  32 . Fluid reservoir  32  supplies fluid to thermal control unit  22  and circulation channel  36  via valve  72 , which may be a conventional check valve, or other type of valve, that automatically opens when reservoir  32  is coupled to thermal control unit  22  and that automatically closes when reservoir  32  is decoupled from thermal control unit  22  (see  FIG. 2 ). After passing by valve  72 , the circulating fluid travels to pump  34  and the circuit is repeated. 
     Controller  60  of thermal control unit  22  is contained within main body  30  of thermal control unit  22  and is in electrical communication with pump  34 , heat exchanger  40 , outlet temperature sensor  56 , bypass valve  68 , a patient temperature module  74 , and a user interface  76 . Controller  60  includes any and all electrical circuitry and components necessary to carry out the functions and algorithms described herein, as would be known to one of ordinary skill in the art. Generally speaking, controller  60  may include one or more microcontrollers, microprocessors, and/or other programmable electronics that are programmed to carry out the functions described herein. It will be understood that controller  60  may also include other electronic components that are programmed to carry out the functions described herein, or that support the microcontrollers, microprocessors, and/or other electronics. The other electronic components include, but are not limited to, one or more field programmable gate arrays, systems on a chip, volatile or nonvolatile memory, discrete circuitry, integrated circuits, application specific integrated circuits (ASICs) and/or other hardware, software, or firmware, as would be known to one of ordinary skill in the art. Such components can be physically configured in any suitable manner, such as by mounting them to one or more circuit boards, or arranging them in other manners, whether combined into a single unit or distributed across multiple units. Such components may be physically distributed in different positions in thermal control unit  22 , or they may reside in a common location within thermal control unit  22 . When physically distributed, the components may communicate using any suitable serial or parallel communication protocol, such as, but not limited to, CAN, LIN, Firewire, I-squared-C, RS-232, RS-465, universal serial bus (USB), etc. 
     User interface  76 , which may be implemented as a control panel or in other manners, allows a user to operate thermal control unit  22 . User interface  76  communicates with controller  60  and includes a display  80  and a plurality of dedicated controls  82 . Display  80  may be implemented as a touch screen, or, in some embodiments, as a non-touch-sensitive display. Dedicated controls  82  may be implemented as buttons, switches, dials, or other dedicated structures. In any of the embodiments, one or more of the functions carried out by a dedicated control  82  may be replaced or supplemented with a touch screen control that is activated when touched by a user. Alternatively, in any of the embodiments, one or more of the controls that are carried out via a touch screen can be replaced or supplemented with a dedicated control  82  that carries out the same function when activated by a user. 
     Through either dedicated controls  82  and/or a touch screen display (e.g. display  80 ), user interface  76  enables a user to turn thermal control unit  22  on and off, select a mode of operation, select a target temperature for the fluid delivered to thermal pads  24 , select a patient target temperature, and control other aspects of thermal control unit  22 . In some embodiments, user interface  76  may include a pause/event control, a medication control, and/or an automatic temperature adjustment control that operate in accordance with the pause event control  66   b,  medication control  66   c,  and automatic temperature adjustment control  66   d  disclosed in commonly assigned U.S. patent application Ser. No. 62/577,772 filed on Oct. 27, 2017, by inventors Gregory Taylor et al. and entitled THERMAL SYSTEM WITH MEDICATION INTERACTION, the complete disclosure of which is incorporated herein by reference. Such controls may be activated as touch screen controls or dedicated controls  82 . 
     In those embodiments where user interface  76  allows a user to select from different modes for controlling the patient&#39;s temperature, the different modes include, but are not limited to, a manual mode and an automatic mode, both of which may be used for cooling and heating the patient. In the manual mode, a user selects a target temperature for the fluid that circulates within thermal control unit  22  and that is delivered to thermal pads  24 . Thermal control unit  22  then makes adjustments to heat exchanger  40  in order to ensure that the temperature of the fluid exiting supply hoses  26   a  is at the user-selected temperature. 
     Another one of the modes is an automatic mode. When the user selects the automatic mode, the user selects a target patient temperature, rather than a target fluid temperature. After selecting the target patient temperature, controller  60  makes automatic adjustments to the temperature of the fluid in order to bring the patient&#39;s temperature to the desired patient target temperature. In this mode, the temperature of the circulating fluid may vary as necessary in order to bring about the target patient temperature. 
     In order to carry out the automatic mode, thermal control unit  22  utilizes patient temperature module  74 . Patient temperature module  74  includes one or more patient temperature sensor ports  84  ( FIGS. 2 &amp; 3 ) that are adapted to receive one or more conventional patient temperature sensors or probes  86 . The patient temperature sensors  86  may be any suitable patient temperature sensor that is able to sense the temperature of the patient at the location of the sensor. In one embodiment, the patient temperature sensors are conventional Y.S.I. 400 probes marketed by YSI Incorporated of Yellow Springs, Ohio, or probes that are YSI 400 compliant. In other embodiments, different types of sensors may be used with thermal control unit  22 . Regardless of the specific type of patient temperature sensor used in thermal control system  20 , each temperature sensor  86  is connected to a patient temperature sensor port  84  positioned on thermal control unit  22 . Patient temperature sensor ports  84  are in electrical communication with controller  60  and provide current temperature readings of the patient&#39;s temperature. 
     Controller  60 , in some embodiments, controls the temperature of the circulating fluid using closed-loop feedback from temperature sensor  56 . That is, controller  60  determines (or receives) a target temperature of the fluid, compares it to the measured temperature from sensor  56 , and issues a command to heat exchanger  40  that seeks to decrease the difference between the desired fluid temperature and the measured fluid temperature. In some embodiments, the difference between the fluid target temperature and the measured fluid temperature is used as an error value that is input into a conventional Proportional, Integral, Derivative (PID) control loop. That is, controller  60  multiplies the fluid temperature error by a proportional constant, determines the derivative of the fluid temperature error over time and multiplies it by a derivative constant, and determines the integral of the fluid temperature error over time and multiplies it by an integral constant. The results of each product are summed together and converted to a heating/cooling command that is fed to heat exchanger  40  and tells heat exchanger  40  whether to heat and/or cool the circulating fluid and how much heating/cooling power to use. 
     When thermal control unit  22  is operating in the automatic mode, controller  60  may use a second closed-loop control loop that determines the difference between a patient target temperature  88  and a measured patient temperature  90  ( FIG. 4 ). The patient target temperature  88  is input by a user of thermal control unit  22  using user interface  76 . Measured patient temperature  90  comes from a patient temperature sensor  86  coupled to one of patient temperature sensor ports  84  ( FIG. 3 ). Controller  60  determines the difference between the patient target temperature  88  and the measured patient temperature  90  and, in some embodiments, uses the resulting patient temperature error value as an input into a conventional PID control loop. As part of the PID loop, controller  60  multiplies the patient temperature error by a proportional constant, multiplies a derivative of the patient temperature error over time by a derivative constant, and multiplies an integral of the patient temperature error over time by an integral constant. The three products are summed together and converted to a target fluid temperature value. The target fluid temperature value is then fed to the first control loop discussed above, which uses it to compute a fluid temperature error. 
     It will be understood by those skilled in the art that other types of control loops may be used. For example, controller  60  may utilize one or more PI loops, PD loops, and/or other types of control equations. In some embodiments, the coefficients used with the control loops may be varied by controller  60  depending upon the patient&#39;s temperature reaction to the thermal therapy, among other factors. One example of such dynamic control loop coefficients is disclosed in commonly assigned U.S. patent application Ser. No. 62/577,772 filed on Oct. 27, 2017, by inventors Gregory Taylor et al. and entitled THERMAL SYSTEM WITH MEDICATION INTERACTION, the complete disclosure of which is incorporated herein by reference. 
     Regardless of the specific control loop utilized, controller  60  implements the loop(s) multiple times a second in at least one embodiment, although it will be understood that this rate may be varied widely. After controller  60  has output a heat/cool command to heat exchanger  40 , controller  60  takes another patient temperature reading (from sensor  86 ) and/or another fluid temperature reading (from sensor  56 ) and re-performs the loop(s). The specific loop(s) used, as noted previously, depends upon whether thermal control unit  22  is operating in the manual mode or automatic mode. 
     It will also be understood by those skilled in the art that the output of any control loop used by thermal control unit  22  may be limited such that the temperature of the fluid delivered to thermal pads  24  never strays outside of a predefined maximum and a predefined minimum. Examples of such a predefined maximum temperature  134  and predefined minimum temperature  136  are shown in  FIGS. 5 and 6 . Minimum temperature  136  is designed as a safety temperature may be set to about four degrees Celsius, although other temperatures may be selected. The predefined maximum temperature  134  is also implemented as a safety measure and may be set to about forty degrees Celsius, although other values may be selected. 
     In the embodiment shown in  FIG. 3 , thermal control unit  22  also includes a reservoir valve  96  that is adapted to selectively move fluid reservoir  32  into and out of line with circulation channel  36 . Reservoir valve  96  is positioned in circulation channel  36  between air remover  70  and valve  72 , although it will be understood that reservoir valve  96  may be moved to different locations within circulation channel  36 . Reservoir valve  96  is coupled to circulation channel  36  as well as a reservoir channel  98 . When reservoir valve  96  is open, fluid from air remover  70  flows along circulation channel  36  to pump  34  without passing through reservoir  32  and without any fluid flowing along reservoir channel  98 . When reservoir valve  96  is closed, fluid coming from air remover  70  flows along reservoir channel  98 , which feeds the fluid into reservoir  32 . Fluid inside of reservoir  32  then flows back into circulation channel  36  via valve  72 . Once back in circulation channel  36 , the fluid flows to pump  34  and is pumped to the rest of circulation channel  36  and thermal pads  24  and/or bypass line  64 . In some embodiments, reservoir valve  96  is either fully open or fully closed, while in other embodiments, reservoir valve  96  may be partially open or partially closed. In either case, reservoir valve  96  is under the control of controller  60 . 
     Thermal control unit  22  also includes a reservoir temperature sensor  100 . Reservoir temperature sensor  100  reports its temperature readings to controller  60 . When reservoir valve  96  is open, the fluid inside of reservoir  32  stays inside of reservoir  32  (after the initial drainage of the amount of fluid needed to fill circulation channel  36  and thermal pads  24 ). This residual fluid is substantially not affected by the temperature changes made to the fluid within circulation channel  36  as long as reservoir valve  96  remains open. This is because the residual fluid that remains inside of reservoir  32  after circulation channel  36  and thermal pads  24  have been filled does not pass through heat exchanger  40  and remains substantially thermally isolated from the circulating fluid. Two results flow from this: first, heat exchanger  40  does not need to expend energy on changing the temperature of the residual fluid in reservoir  32 , and second, the temperature of the circulating fluid in circulation channel  36  will deviate from the temperature of the residual fluid as the circulating fluid circulates through heat exchanger  40 . 
     Controller  60  utilizes a temperature control algorithm to control reservoir valve  96  that, in some embodiments, is the same as the temperature control algorithm  160  disclosed in commonly assigned U.S. patent application Ser. No. 62/577,772 filed on Oct. 27, 2017, by inventors Gregory Taylor et al. and entitled THERMAL SYSTEM WITH MEDICATION INTERACTION, the complete disclosure of which is incorporated herein by reference. In other embodiments, controller  60  utilizes a different control algorithm. In still other embodiments, thermal control unit  22  is modified to omit reservoir valve  96 , reservoir channel  98 , and reservoir temperature sensor  100 . Thermal control unit  22  may also be modified such that reservoir  32  is always in the path of circulation channel  36 . Still other modifications are possible. 
       FIG. 4  illustrates one example of a thermal therapy graph  102  that may be displayed by controller  60  on display  80  of user interface  76 . Graph  102  is displayable at any time during a thermal therapy session implemented using thermal control unit  22 , as well as any time after such a thermal therapy session is complete. That is, controller  60  records the data shown in graph  102  and makes it available for display on display  80  not only during a thermal therapy session, but also after a thermal therapy session. 
     Thermal therapy graph  102  includes an X-axis  104  that corresponds to time and a Y-axis  106  that corresponds to temperature. Thermal therapy graph  102  shows a history of a patient&#39;s actual temperature readings  90  compared to a patient target temperature  88 . Thermal therapy graph  102  also includes a plurality of event icons  108  that are positioned at locations along the X-axis  104  corresponding to the times at which the events associated with event icons  108  occurred. For example, event icon  108   a corresponds to a patient shivering event. The location of icon  108   a  along X-axis  104  represents the time at which the shivering occurred. In some embodiments, thermal control unit  22  is adapted to automatically detect the patient shivering and to place event icon  108   a  on graph  102  without any user intervention. At least one method by which thermal control unit  22  can automatically detect patient shivering is disclosed in commonly assigned U.S. patent application Ser. No. 62/425,813 filed Nov. 23, 2016, by inventors Gregory Taylor et al. and entitled THERMAL SYSTEM, the complete disclosure of which is incorporated herein by reference. Other methods of shivering detection may also be used. 
     In addition to, or in lieu of, the automatic detection of shivering, thermal control unit  22  may be adapted to allow a user to manually enter data indicating that a patient experienced shivering, including a time when the shivering occurred. In this manner, a user may either directly insert an icon  108  onto graph  102  or may input data into thermal control unit  22  via user interface  76  that specifies that a shivering event took place and the time of the event. In response, controller  60  records the data internally within a memory inside of thermal control unit  22  and displays shivering event icon  108   a  on graph  102  whenever graph  102  is displayed on display  80 . 
     User interface  76  of thermal control unit  22  is also adapted to display other types of event icons on thermal therapy graph  102 . Event icon  108   b,  for example, corresponds to a sedation event. That is, at the time of event icon  108   b  along the X-axis shown in  FIG. 4 , the patient was administered a sedative. Data indicating a sedation event has occurred is input by a user into thermal control unit  22  and controller  60 , in response thereto, saves the data and displays event icon  108   b  on graph  102 . 
     As another example, event icon  108   c  indicates a patient transfer event. The patient transfer event refers to an event where the patient was transferred to thermal control unit  22  from another thermal control unit, which may be another thermal control unit of the same type as thermal control unit  22 , or it may be a thermal control unit of a different type (e.g. a portable thermal control unit, a thermal control unit with a different thermal capacity or other characteristics, etc.). The patient transfer event corresponding to patient transfer event icon  108   c  is detected either manually or automatically. When done so automatically, data indicating the transfer event may be received from the previous thermal control unit or it may be detected by means on board thermal control unit  22 . When received from another thermal control unit, the data indicative of the transfer event (as well as the data shown in  FIG. 4  that precedes the transfer event) may be communicated in any of the manners disclosed in commonly assigned U.S. patent application Ser. No. 15/616,574 filed Jun. 7, 2017, by inventors Gregory Taylor et al. and entitled THERMAL CONTROL SYSTEM, the complete disclosure of which is incorporated herein by reference. Other manners of receiving the data may, of course, be used. When the patient transfer event data is detected manually, a user of thermal control system  20  enters data into thermal control unit  22  via user interface  76  indicating the transfer event. 
       FIG. 4  also illustrates a plurality of additional event icons  108   d,    108   e,    108   f,  and  108   g.  It will be understood by those skilled in the art that the particular number of event icons  108  and their placement on thermal therapy graph  102  will vary from patient to patient according to the specific thermal therapy applied to that particular patient. It will also be understood that other events besides shivering, sedation, and patient transfer may be indicated on graph  102 . One such additional event is the administration of a paralytic to the patient. Another event is the administration of yet another type of drug. Still other events include, but are not limited to, the following: adjustment, relocation, cleaning, and/or replacement of one or more thermal pads  24  on the patient; adjustment, relocation, cleaning, and/or replacement of a temperature sensor  86 ; changing of a setting on thermal control unit  22  (e.g. a rate of heating or cooling, a range of acceptable fluid temperature, etc.); performance of a maintenance task associated with the thermal control unit; detection of an error and/or a patient alert event (e.g. a low potassium level, an elevated blood pressure, a low blood pressure, a low oxygen level, etc.); and/or flushing a patient&#39;s body adjacent a temperature sensor. 
     In some embodiments of thermal control unit  22 , controller  60  is also programmed to allow a user to input customized event data. The data, including a time associated with the data, is input using user interface  76 t. Controller  60  then displays an event icon  108  on graph  102  at a time location corresponding to the input time data. The customized event icon  108  may include a name or identifier associated with it that is dictated by the user, or it may include a different type of identifier, or no identifier at all. 
     As can be seen in  FIG. 4 , each event icon  108  is shaped and/or sized differently according to the type of event it corresponds to. Thus, the shivering event icons  108   a,    108   d,  and  108   f  are square shaped; the sedation event icons  108   b,    108   e,  and  108   g  are circle shaped; and the patient transfer event  108   c  is triangle shaped. Although not illustrated, each type of event icon  108  may also be differently colored according to its type. If other types of event icons  108  are displayed on a graph  102  for a particular patient&#39;s thermal therapy session, those event icons  108  may be shaped and/or colored in still other manners according to their type. 
     Additional data beyond an event type and time may also be input into thermal control unit  22  and/or generated internally by thermal control unit  22  for one or more of the event icons  108 . In some embodiments, the additional data is viewable by a user after touching or pressing on display  80  (when implemented as a touch screen) in the area of the icon  108 . For any of the event icons  108  related to the administration of a drug, such additional data includes one or more of the following: a more precise time of administration, an identification of the particular drug administered, the amount of the drug given, an identification of who administered the drug, a method of administration, and/or other information. For a shivering event, touching a corresponding event icon  108  causes controller  60  to display on display  80  further information about the shivering event, such as, but not limited to, the length of time of the shivering, an indication of the degree of shivering (e.g. a Bedside Shivering Assessment Scale (BSAS) number), a graph of the shivering vibrations as detected, for example, by an accelerometer or other sensor positioned on or near the patient, and/or other information about the shivering. For a patient transfer event, touching a corresponding event icon  108  causes controller  60  to display on display  80  further information about the transfer event, such as, but not limited to, the location of the transfer, an identification of the previously used equipment, and an identification of any previous settings used prior to the transfer. For customized events, touching a corresponding event icon causes controller  60  to display additional information that is available regarding the event associated with the customized event icon  108 . The user can select which of the additional information is to be viewed and input configuration data into thermal control unit  22  so that controller  60  only displays the selected additional information. 
       FIGS. 5-6  illustrate another example of a thermal therapy graph  102 ′. Thermal therapy graph  102 ′ represents an illustrative set of patient temperature readings  90 , patient target temperatures  88 , and fluid temperatures  110  that might be generated during a thermal therapy session using thermal control system  20 . Fluid temperatures  110  are generated from outlet temperature sensor  56 . The patient temperature readings  90 , patient target temperatures  88 , and fluid temperatures  110  in  FIGS. 5 and 6  are the same. The difference between the two figures is the addition of a plurality of event icons  108  in graph  102 ′ of  FIG. 5  and the removal of those event icons  108  in graph  102 ′ of  FIG. 6 . This difference illustrates a display filtering feature that is incorporated into some embodiments of thermal control unit  22 . 
     More specifically,  FIG. 6  illustrates a display control window  112  that is displayed on display  80  along with graph  102 ′. Display control window  112  identifies a plurality of display parameters  114 . The display parameters  114  illustrated in  FIG. 6  include patient temperature, water (fluid) temperature, shivering, sedation administration, and a patient&#39;s low potassium level. Other display parameters may, of course, be added to control window  112 . Next to each display parameter  114  is a check box  116  that, when selected by a user, causes controller  60  to display on thermal therapy graph  102 ′ the corresponding display parameter. When the check box  116  is not selected by a user, then the corresponding display parameter  114  is not shown by controller  60  on thermal therapy graph  102 ′. Display control window  112  and check boxes  116  therefore act together to provide a filtering function for the information displayable on display  80 . 
     Thus, in the example of  FIG. 6 , it can be seen that the display parameters  114  corresponding to patient temperature and fluid temperature are checked, while the display parameters  114  corresponding to shivering, sedation, and low potassium are not checked. As a result of this selection, controller  60  displays graph  102 ′ with the patient temperature readings  90  and fluid temperature readings  110  shown thereon, but does not include on graph  102 ′ any event icons  108  corresponding to shivering, sedation, and/or low potassium levels. In the example shown in  FIG. 5 , in contrast, the user has selected all of the display parameters  114  and controller  60  therefore displays, in addition to the patient temperatures  90  and fluid temperature  110 , event icons  108  corresponding to patient shivering, sedation, and low potassium levels. 
     Although not shown in  FIG. 5 , display control window  112  may also be displayed in that view. Indeed, in some embodiments, an icon on graph  102 ′ (not shown) may be included that, when toggled, causes display control window  112  to alternatively be displayed and not displayed on display  80 . Alternatively, or additionally, another control of user interface  76 , such as, but not limited to, a dedicated control  82 , may control the selective displaying of control window  112 . The selection and deselection of check boxes  116  of control window  112  allows a user to selectively declutter the information contained on graph  102 ′ and/or customize the information of interest to a particular clinician. 
       FIG. 7  illustrates another example of a thermal therapy graph  102 ″. Thermal therapy graph  102 ″ includes a number of additional features that may be displayed on graphs  102  and/or  102 ′. These features include a control window  118 , a current value window  120 , and a current location indicator  122 . Control window  118  includes one or more controls for entering information into thermal control unit  22  and/or for controlling the manner in which information is displayed on display  80 . These controls include a medication control  124  and a patient target temperature  126 . Control window  118  also includes a settings control  128 . 
     Medication control  124  is pressed by a user when the user wishes to input information into thermal control unit  22  about a medication administered to the patient undergoing thermal therapy. In some embodiments, when medication control  124  is pressed, a window appears in which data regarding the medication can be input, such as the type of medication, the amount, the time, etc. After the data is input, controller  60  displays a medication icon  108  on thermal therapy graph  102 ″ in the location corresponding to the time the medication was administered (assuming the check box  116  corresponding to that medication has not been unchecked). 
     Patient target temperature control  126  is pressed by a user when the user wishes to enter and/or change the patient target temperature  88  for the patient. In some embodiments, when patient target temperature control  126  is pressed, a window appears in which the target temperature and corresponding times for the target temperature can be input. In other embodiments, a user is able to set the patient target temperature by drawing with his or her finger (or stylus, or other touch-screen writing device) a line or set of lines, a curve or a set of curves, or one or more other shapes on graph  102 ″ that define the patient target temperature  88  for the time periods corresponding to the drawn line(s), curve(s) and/or other shape(s). Thus, the line segments in  FIG. 7  corresponding to the patient target temperature  88  can be input into thermal control unit  22  by a user drawing the shape shown therein after pressing on target temperature control  126 . 
     Current value window  120  of  FIG. 7  displays one or more current values regarding the thermal therapy session being applied to a patient using thermal control system  20 . In the example shown in  FIG. 7 , these current values include the current patient temperature (as measured by patient temperature sensor  86 ) and the current patient target temperature  88 , as input by a user via user interface  76 . These are merely two examples of the type of information displayable in current value window  120 . Additional examples include, but are not limited to, any one or more of the following: the current fluid temperature, current patient data (e.g. potassium levels, blood pressure, heart rate, respiration rate, oxygen levels, etc.), a current power level of heat exchanger  40 , a current flow rate of the circulating fluid, and other data regarding the operation of thermal control unit  22 . 
     Thermal therapy graph  102 ″ also includes current location indicator  122  ( FIG. 7 ). Current location indicator  122  indicates where along time axis  104  the current thermal therapy session has progressed to. Current location indicator  122  may be shaped and/or colored in any manner that provides an easy visual indication to a user of where the thermal therapy is in relation to the time axis  104  and the patient target temperature  88 . 
     Settings control  128 , when pressed or otherwise activated by a user, brings up a window (not shown) that allows a user to control various settings regarding the display of information on display  80 , including, but not limited to, settings regarding the thermal therapy graph  102 ″. In some embodiments, settings control  128  is selected in order to bring up display control window  112  ( FIG. 6 ). In some embodiments, settings control  128  is also selected in order to change the size, color, contrast, and/or other settings regarding the data displayed on display  80  and/or graph  102 ″. 
       FIG. 8  illustrates another example of a thermal therapy graph  102 ′″. Thermal therapy graph  102 ′″ illustrates a fluid temperature control feature that may be included with thermal control unit  22  and that may be incorporated into any of the thermal therapy graphs  102 ,  102 ′, and/or  102 ″. Thermal therapy graph  102 ″ includes a maximum permissible fluid temperature setting  130  and a minimum permissible fluid temperature setting  132 . Maximum permissible fluid temperature setting  130  refers the maximum permissible temperature of the circulating fluid delivered to thermal pads  24 . Minimum permissible fluid temperature setting  132  refers to the minimum permissible temperature of the circulating fluid delivered to thermal pads  24 . 
     Thermal control unit  22  includes, as noted previously, a default maximum permissible fluid temperature setting  134  and a default minimum permissible fluid temperature setting  136  ( FIGS. 5, 6 , &amp;  8 ). User interface  76 , however, is configured to allow a user to change these default maximum and/or minimum temperature settings  134  and  136 . Further, user interface  76  is configured to allow a user to specify the time period during which these default maximum and/or minimum temperatures settings  134  and/or  136  are to be changed. As can be seen in the example of  FIG. 8 , the user has set maximum permissible fluid temperature  130  and minimum permissible fluid temperature  132  for the time period between T 1  and T 2.  In the times outside of the time period between T 1  and T 2,  the maximum and minimum permissible fluid temperatures are set by the default values  134  and  136 . 
     Although  FIG. 8  illustrates maximum and minimum permissible fluid temperatures  130  and  132  as horizontal lines, it will be understood that either or both of these lines can be sloped, angled, or configured however desired by a user. In some embodiments, user interface  76  is configured to allow a user to set temperatures  130  and  132  by simply drawing one or more lines on thermal therapy graph  102 ′″, and/or filling in one or more areas of graph  102 ′″. In those areas where no such line is drawn or no such area is filled in (if any), the default maximum and minimum temperatures  134  and  136  are followed by controller  60 . Still further, in some embodiments, controller  60  is configured such that a user can configure the maximum and/or minimum fluid temperatures  130  and/or  132  not as absolute values, but instead as maximum and minimum temperatures relative to the patient&#39;s current temperature. In some embodiments, controller  60  allows a user to configure such relative maximum and minimum temperatures by drawing one or more lines on graph  102 ′″. In other embodiments, a window is displayed on display  80  allowing a user to enter the desired maximum and/or minimum temperatures relative to the patient&#39;s temperature. 
     When user interface  76  of thermal control unit  22  includes a touch screen display  80 , controller  60  is adapted, in at least some embodiments, to allow a user to zoom in on, and zoom out from, any of the data shown in graphs  102 . Such zooming in and zooming out is carried out in some embodiments in the same way a conventional smart phone operates. For example, the pinching of a users fingers closer together on the touch screen causes controller  60  to zoom out; and the expanding of a users fingers farther apart on the touch screen  80  causes controller  60  to zoom in. Alternatively, or additionally, double tapping on the touch screen display will cause controller  60  to enlarge (zoom in on) the information currently being displayed. Further, in some embodiments, the information displayed is shown in one or more windows that may be resized, moved, and/or opened and closed via the user&#39;s fingers interacting with the touch screen display  80 . 
       FIG. 9  illustrates an alternative embodiment of a thermal control unit  22 ′. Those elements of thermal control unit  22 ′ that are the same as thermal control unit  22  are labeled with the same reference number and, unless explicitly mentioned otherwise below, operate in the same manner as described with respect to thermal control unit  22 . Those elements of thermal control unit  22 ′ that are new are provided with a new reference number, and those elements of thermal control unit  22 ′ that are similar but modified from thermal control unit  22  are provided with the same reference number followed by a prime (′) symbol. 
     Thermal control unit  22 ′ of  FIG. 9  differs from thermal control unit  22  in that thermal control unit  22 ′ is adapted to independently control the temperature of the fluid that is delivered to each of the three outlet ports  58 . That is, heat exchanger  40 ′ includes three fluid outlets  140   a,    140   b,  and  140   c,  which are supplied with temperature-controlled fluid by heat exchanger  40 ′, and the temperature of the fluid in each outlet  140   a,    140   b,  and/or  140   c  may be different from the temperature in one or both of the other outlets  140 . Each outlet  140   a,    140   b,  and  140   c,  after passing through a triple bypass valve  68 ′, is coupled to one of the fluid outlet ports  58  of thermal control unit  22 ′. 
     Heat exchanger  40 ′ is able to deliver fluid with independently controlled temperatures by using a set of inlet valves  142  and a set of outlet valves  144 . Inlet valves  142  divide the incoming fluid into one or more of three possible paths through heat exchanger  40 ′. These three paths include a heating path  146 , a cooling path  148 , and a neutral path  150 . Heating path  146  passes through a heater  44 ′; cooling path  148  passes through a chiller  42 ′, and neutral path  150  does not pass through either a heater or a chiller. Each path  146 ,  148 , and  150  feeds into outlet valves  144  which, like inlet valves  142 , are under the control of controller  60 . Controller  60  controls the outlet valves  144  such that the heated fluid from path  146 , the cooled fluid from path  148 , and the unchanged fluid from path  150  are mixed in the proper proportions to deliver fluid to each of the outlets  140  at each of the desired temperatures. 
     Controller  60  controls the inlet and outlet valves  142  and  144  based on the incoming fluid temperature, which is sensed by temperature sensor  152 . Controller  60  uses the output from temperature sensor  152 , along with the target temperature for each fluid outlet  140   a,    140   b,  and  140   c  to determine how much fluid to direct along each of the paths  146 ,  148 , and  150  and how to mix the fluid from each path, via outlet valves  144 , such that the fluid delivered to each outlet  140   a,  b, and c matches the target temperature for that outlet. 
     By delivering fluid with independently controlled temperatures to each of the outlet ports  58 , thermal control unit  22 ′ is able to provide different levels of heating and/or cooling to the individual thermal pads  24  applied to a patient  28 . In this manner, for example, fluid of a first temperature might be delivered to the thermal pad  24  in contact with the patient&#39;s torso, while fluid of a second temperature might be delivered to the thermal pads  24  in contact with the patient&#39;s thighs. Alternatively, fluid of different temperatures might be delivered to all three thermal pads  24 . Still other combinations of temperatures for the thermal pads  24  are also possible. 
     Thermal control unit  22 ′ also differs from thermal control unit  22  in that it includes a plurality of flow control valves or restrictors  154 . Each restrictor  154  is positioned in the fluid path of one of the three outlet ports  58 . Restrictors  154  are under the control of controller  60  and allow controller  60  to control the amount of fluid that is output from outlet ports  58 . Restrictors  154  therefore allow controller  60  to not only independently control the temperature of the fluid delivered to each thermal pad  24 , but also to independently control the amount of fluid delivered to each thermal pad  24 . 
     In the illustrated embodiment of  FIG. 9 , thermal control unit  22 ′ also includes an outlet temperature sensor  156  for each of the outlet ports  58 . These may be included in order to allow controller  60  to use positive feedback for the temperature control of each fluid outlet  140   a - c.  These may also be included in order for controller  60  to calculate the Q value (or heat quantity) that is delivered to each thermal pad  24 , or absorbed by each thermal pad  24 , as will be discussed in greater detail below. 
     Thermal control unit  22 ′ also differs from thermal control unit  22  in that it includes individual inlet temperature sensors  158  and individual flow meters  160  positioned inside, or in line with, inlet manifold  78 . Each inlet temperature sensor  158  measure the temperature of the fluid returning from a corresponding thermal pad  24  and reports the temperature to controller  60 . Each flow meter  160  measures the flow rate of the fluid returning from a corresponding thermal pad  24  and reports to the measured flow rate to controller  60 . Controller  60  uses the individual temperatures and flow rates for purposes discussed in more detail below, such as the calculation of Q values for each thermal pad  24  and for feedback purposes (e.g. flow meters  160  may be used as closed loop feedback for controlling restrictors  154 ). 
     Thermal control unit  22 ′ includes a user interface  76  that is adapted to display information regarding one or more thermal therapy sessions, as well as to control any aspect of thermal control unit  22 ′. In some embodiments, user interface  76  is adapted to display any of the graphs  102 , as wells as to include any of the display functionality, discussed previously with respect to thermal control unit  22 . Further, because thermal control unit  22 ′ is adapted to individually control thermal therapy pads  24 , controller  60  of thermal control unit  22 ′ is adapted to display individual graphs  102  for each of the thermal pads  24 . Alternatively, or additionally, controller  60  may be adapted to display a single graph  102  that shows the measured fluid temperatures for each of the thermal pads  24 , or the target fluid temperatures for each of the thermal pads  24 , or a combination (e.g. average) of the fluid temperatures for the multiple thermal pads  24 . The display of the multiple fluid temperature readings can be selectively enabled and disabled via a display filtering function, such as via a display control window  112  adapted to list display parameters  114  and check boxes  116  corresponding to the various fluid temperatures. 
     In at least one embodiment, user interface  76  of thermal control unit  22 ′ is adapted to display an image  162  of a human body, such as the image  162  shown in  FIG. 10 . Image  162  is representative of a patient  28  undergoing thermal treatment using thermal control unit  22 ′. Image  162  includes a torso zone  164 , a right thigh zone  166 , a left thigh zone  168 , and a neck zone  170 . Torso zone  164  corresponds to a thermal pad  24  wrapped around a patient&#39;s torso, and right and left thigh zones  166  and  168  correspond to thermal pads  24  wrapped around the patient&#39;s right and left legs, respectively. Neck zone  170 , which may be omitted, corresponds to an esophageal heat transfer device that, in some embodiments, receives temperature-controlled fluid from thermal control unit  22 ′. 
     For each of the zones  164 - 170  shown on image  162 , controller  60  displays a set of information corresponding to that particular zone. In the example of  FIG. 10 , controller  60  displays with torso zone  164  a peripheral temperature  172 , a core temperature  174 , and a fluid temperature  176 . Peripheral temperature  172  corresponds to a temperature reading taken in the torso region of the patient that is skin based, or otherwise representative of the temperature of the periphery of the patient&#39;s torso. In some embodiments, one or more temperature sensors are incorporated into the thermal pad  24  that is wrapped around the patient&#39;s torso and the temperature sensors are positioned in contact with the patient&#39;s skin, but thermally insulated from the fluid being circulated through the thermal pads. 
     Although other designs may be used, some suitable examples thermal pads incorporating temperature sensors that may be used for detecting peripheral temperature  172  are found in commonly assigned U.S. patent application Ser. No. 62/425,813 filed Nov. 23, 2016, by inventors Gregory Taylor et al. and entitled THERMAL SYSTEM, as well as commonly assigned U.S. patent application Ser. No. 15/675,066 filed Aug. 11, 2017, by inventor James K. Galer and entitled THERMAL SYSTEM, the complete disclosures of both of which are hereby incorporated by reference in their entirety herein. Regardless of whether the peripheral temperature sensor(s) are incorporated into a thermal pad  24  or not, the outputs from the temperature sensor(s) are fed to controller  60 . In some embodiments, the sensor outputs are fed to controller  60  via cables coupled from the temperature sensors to patient temperature input ports  84 . It will be understood that thermal control unit  22 ′ can include more patient temperature input ports  84  than the three shown in  FIG. 10 . 
     Core temperature  174  of  FIG. 10  refers to the core temperature of the patient as measured by patient temperature sensor  86 . Patient temperature sensor  86  may be a conventional temperature sensor that is positioned in the patient&#39;s esophagus, rectum, or other location where temperature readings are indicative of the core temperature of the patient. Fluid temperature  176  of  FIG. 10  refers to the temperature of the fluid delivered to the thermal pad  24  and may be measured by a temperature sensor positioned in the pad, by temperature sensors  156 , and/or by a combination of one or more of these and/or other temperature sensors (e.g. a combination of outlet temperature sensors  156  and inlet temperature sensors  158 ). 
     In the example shown in  FIG. 10 , which corresponds to a touch screen implementation of display  80 , controller  60  displays additional information about torso zone  164  when a user of thermal control unit  22 ′ touches the torso portion of image  162 . Some of this additional information is shown in  FIG. 10 , although it will be understood that additional and/or alternative information may be displayed besides the particular information shown in  FIG. 10 . In the example of  FIG. 10 , controller  60  displays additional information about the fluid temperature and fluid flow in torso zone  164  in response to a user touching the torso portion of image  162 . The additional information includes a current reading column  178 , a current setting column  180 , and a change column  182 . Current reading column  178  displays the current readings for each row of parameters displayed on display  80 . Thus, in the example, shown in  FIG. 10 , controller  60  displays the current fluid temperature reading (five degrees Celsius) for torso zone  164  and the current flow rate (1.2 liters per minute) for torso zone  164 . The flow reading may originate from the flow meter  160  that is in fluid communication with the torso thermal pad  24 , or from another flow sensor. 
     Current setting column  180  ( FIG. 10 ) displays the current settings for each row of parameters displayed on display  80 . In the example of  FIG. 10 , the current setting for the fluid temperature is “Max Cooling.” This means that thermal control unit  22 ′ is using the coldest available fluid (within permissible limits  130 - 136 , as applicable) to cool the patient. In many embodiments, thermal control unit  22 ′ is configured to allow a user to set different levels of cooling that are less than “Max Cooling.” Such different levels of cooling use fluid temperatures that differ from the patient&#39;s temperature by a smaller magnitude. For example, a “Min Cooling” setting might cause controller  60  to only supply fluid to a thermal pad  24  that had a temperature that was no more than, say, five degrees cooler than the patient&#39;s current temperature. Intermediate cooling settings may also be specified. Still further, in some embodiments, the user may specify an actual temperature for the circulating fluid, or a specific Q rate of heat removal or addition. 
     For the fluid flow, the current setting in the current setting column  180  of  FIG. 10  is indicated as 100%. This indicates that the restrictor  154  in fluid communication with the patients&#39; torso thermal pad  24  is completely open and a full amount of fluid is being delivered to that thermal pad  24 . If less than a full amount of fluid is desirably delivered to the torso thermal pad, a user can change the setting to any value less than 100%. 
     Change column  182  allows a user to change the current setting to a different setting. In the example shown in  FIG. 10 , controller  60  has provided a suggested change for the current setting. For example, controller  60  has suggested changing the “Max Cooling” setting to a “10° C. limit” setting and the 100% flow rate setting to a 66% flow rate setting. It will be understood that there are other values that a user can choose for changing these settings. In some embodiments, a user touches display  80  in the area of the suggested setting change to implement the suggested change. A confirmation window may appear in order to allow the user to confirm the desired setting. If the user wishes to change the setting in a manner other than the one suggested, the user can, in at least some embodiments, touch the area of the current setting and a setting change window (not shown) is displayed on display  80 . The setting change window includes a list of settings to choose from and/or it includes one or more fields for a user to enter the desired new setting. 
     One of the additional items of information that may be displayed on display  80  for a particular zone is a Q value. The Q value refers to the amount of heat being added to, or removed from, the patient via the corresponding thermal pad. This value is calculated, in at least some embodiments, by determining the difference in temperature between the fluid delivered to the corresponding thermal pad  24  and the fluid returned from the corresponding thermal pad, and then multiplying this temperature difference by the flow rate (in mass per unit of time) and the specific heat capacity of the particular type of fluid (such as, but not limited to, water) being used with thermal control unit  22 ′. The result is the amount of heat energy being delivered per unit of time via that particular thermal pad  24  (when being used to warm the patient) or the amount of heat energy being absorbed per unit of time via that particular thermal pad  24  (when being used to cool the patient). In some embodiments, the total quantity of heat delivered or absorbed during the thermal therapy session may also or alternatively be displayed for each zone. 
     Controller  60  is configured to display any of the aforementioned information for each of the thermal pads  24  in each of the zones  164 ,  166 ,  168 , and  170 . In the illustrated embodiment, a user simply touches on the area of image  162  corresponding to the particular zone of interest and controller  60  automatically displays the information corresponding to that particular zone. For example, if a user wishes to determine more information about the right thigh zone  166 , the user can touch on the right thigh of the human image  162  and controller  60  displays information pertaining to the right thigh zone. In some embodiments, controller  60  is configured to provide the user with the option of viewing one or more graphs, such as any of the graphs  102  discussed above, for each of the zones  164 - 170 . Alternatively, or additionally, controller  60  may be configured to display graphs  102  that combine information from each of the zones into a single graph  102 . The combination may be accomplished through averaging, by superimposing data from each zone onto the graph, or by other methods. Still other data may be combined, such as a combined Q value for all of the zones, a combined flow rate, a combined fluid temperature (e.g. an average fluid temperature), etc. 
     In some embodiments, controller  60  is not configured to display any information regarding neck zone  170  because thermal control system  20  may be implemented without providing any temperature-controlled fluid to the patient&#39;s neck region. (Controller  60  may also be configured to omit any of the other zones  164 ,  166 , and  168  if a corresponding thermal pad is not used). When thermal control unit  22 ′ is used to provide temperature-controlled fluid to a patient&#39;s neck region, thermal control unit  22 ′ may be fluidly coupled to an esophageal heat transfer device  184  ( FIG. 9 ). One such suitable esophageal heat transfer device  184  is the ensoETM available from Attune Medical of Chicago, Ill. The ensoETM is inserted into a patient&#39;s esophagus and comes into contact with the esophageal mucosa, allowing blood passing through the patient&#39;s blood vessels to be cooled or warmed by the temperature-controlled fluid circulating through the ensoETM. Still other types of esophageal thermal transfer devices may be used. Regardless of the specific type, thermal control unit  22 ′ displays the temperature of the fluid delivered to the esophageal thermal transfer device and/or other information about the device. 
     Although not illustrated in  FIG. 9 , thermal control unit  22 ′ may be modified to include an additional fluid outlet port  58  and an additional fluid inlet port  62  to provide fluid to, and receive fluid back from, the esophageal heat transfer device  184 . Alternatively, one of hoses  26   a  may be coupled to a divider that divides its fluid flow so as to deliver fluid to both a thermal pad  24  and an esophageal heat transfer device  184  (or to two thermal pads  24 , thereby allowing esophageal heat transfer device  184  to have its own dedicated hose  26   a  coupled to one of the three outlet ports  58 ). In such an embodiment, one or more of hoses  26   b  are joined together to receive returning fluid from both a thermal pad  24  and esophageal heat transfer device  184  (or from two thermal pads  24 , thereby allowing the esophageal heat transfer device  184  to have its own dedicated return hose  26   b  coupled to one of the three inlet ports  62 ). 
     It will also be understood that any of the thermal control units disclosed herein may be modified to additionally operate in conjunction with one or more auxiliary sensors used to sense one or more non-temperature patient parameters. When so modified, any of the thermal control units disclosed herein may utilize the auxiliary sensors in any of the manners, and using any of the structures and/or algorithms, disclosed in commonly assigned U.S. patent application Ser. No. 62/610,327 filed Dec. 26, 2017, by inventors Gregory S. Taylor et al. and entitled THERMAL SYSTEM WITH PATIENT SENSOR(S), the complete disclosure of which is incorporated herein by reference. 
     Any of the thermal control units disclosed herein may also or alternatively be modified to incorporate any of the temperature overshoot reduction methods, structures, and/or algorithms disclosed in commonly assigned U.S. patent application Ser. No. 62/610,319 filed Dec. 26, 2017, by inventors Gregory Taylor et al. and entitled THERMAL SYSTEM WITH OVERSHOOT REDUCTION, the complete disclosure of which is incorporated herein by reference. Additionally or alternatively, any of the thermal control units disclosed herein may use any of the data and algorithms disclosed in U.S. patent application Ser. No. 62/610,334 filed Dec. 26, 2017, by inventors Christopher Hopper et al. and entitled THERMAL CONTROL SYSTEM when determining when a patient&#39;s core temperature will reach its temperature, and/or when to transition from heating the circulating fluid to cooling the circulating fluid, and vice versa, in order to reduce overshoot. The &#39;334 application is hereby incorporated herein by reference in its entirety. 
     Various other alterations and changes beyond those already mentioned herein can be made to the above-described embodiments. This disclosure is presented for illustrative purposes and should not be interpreted as an exhaustive description of all embodiments or to limit the scope of the claims to the specific elements illustrated or described in connection with these embodiments. For example, and without limitation, any individual element(s) of the described embodiments may be replaced by alternative elements that provide substantially similar functionality or otherwise provide adequate operation. This includes, for example, presently known alternative elements, such as those that might be currently known to one skilled in the art, and alternative elements that may be developed in the future, such as those that one skilled in the art might, upon development, recognize as an alternative. Any reference to claim elements in the singular, for example, using the articles “a,” “an,” “the” or “said,” is not to be construed as limiting the element to the singular.