Patent Publication Number: US-2022233347-A1

Title: Transparent Pad

Description:
PRIORITY 
     This application claims the benefit of priority to U.S. Provisional Application No. 63/141,358, filed Jan. 25, 2021, which is incorporated by reference in its entirety into this application. 
    
    
     BACKGROUND 
     The effect of temperature on the human body has been well documented and the use of targeted temperature management (TTM) systems for selectively cooling and/or heating bodily tissue is known. Elevated temperatures, or hyperthermia, may be harmful to the brain under normal conditions, and even more importantly, during periods of physical stress, such as illness or surgery. Conversely, lower body temperatures, or mild hypothermia, may offer some degree of neuroprotection. Moderate to severe hypothermia tends to be more detrimental to the body, particularly the cardiovascular system. 
     Targeted temperature management can be viewed in two different aspects. The first aspect of temperature management includes treating abnormal body temperatures, i.e., cooling the body under conditions of hyperthermia or warming the body under conditions of hypothermia. The second aspect of thermoregulation is an evolving treatment that employs techniques that physically control a patient&#39;s temperature to provide a physiological benefit, such as cooling a stroke patient to gain some degree of neuroprotection. By way of example, TTM systems may be utilized in early stroke therapy to reduce neurological damage incurred by stroke and head trauma patients. Additional applications include selective patient heating/cooling during surgical procedures such as cardiopulmonary bypass operations. 
     TTM systems circulate a fluid (e.g., water) through one or more thermal contact pads coupled to a patient to affect surface-to-surface thermal energy exchange with the patient. In general, TTM systems include a TTM fluid control module coupled to at least one contact pad via a fluid deliver line. One such TTM system is disclosed in U.S. Pat. No. 6,645,232, titled “Patient Temperature Control System with Fluid Pressure Maintenance” filed Oct. 11, 2001 and one such thermal contact pad and related system is disclosed in U.S. Pat. No. 6,197,045 titled “Cooling/heating Pad and System” filed Jan. 4, 1999, both of which are incorporated herein by reference in their entireties. As noted in the &#39;045 patent, the ability to establish and maintain thermally intimate pad-to-patient contact is of importance to fully realizing medical efficacies with TTM systems. 
     In some instances, the application of a medical device such as a pad, for example, may cause some irritation of the patient&#39;s skin. In some instances, irritation may be caused by abrasion of the skin by the pad, particularly along a perimeter of the pad. In other instances, irritation of the skin may be caused by reduced breathability of the skin. In some instances, it may be advantageous for the clinician to visually observe the skin beneath the pad to assess the state of irritation so that corrective action may be taken to resolve the irritation. In a case of TTM therapy, it may be advantageous for the clinician to assess the state irrational without disrupting the TTM therapy. In summary, TTM systems and methods that minimize skin irritation and/or provide for easy assessment of skin irritation may reduce complications of performing the TTM therapy and reduce discomfort of the patient during TTM therapy. Disclosed herein are embodiments of devices and methods for resolving skin irritation while performing TTM therapy. 
     SUMMARY OF THE INVENTION 
     Briefly summarized, disclosed herein is a medical pad for exchanging thermal energy between a targeted temperature management (TTM) fluid and a patient. The pad includes a top side and a bottom side. The pad further includes a fluid containing layer disposed between the top side and the bottom side, wherein the fluid containing layer is configured for containing the TTM fluid. The fluid containing layer includes a fluid inlet and a fluid outlet and the TTM fluid is circulatable within the fluid containing layer from the fluid inlet to the fluid outlet. The pad further includes an insulation layer disposed the top side, and a thermal conduction layer disposed on the bottom side. In use, the pad is disposed in contact with a skin of a patient, and a perimeter of the pad is configured to inhibit irritation of the skin of the patient along the perimeter. 
     The pad may further include a chamfered edge extending along the perimeter of the pad, and in some embodiments, chamfered edge is a top edge of the pad. The pad may also include a rounded edge extending along the perimeter of the pad. The rounded edge may include a tube extending along the perimeter, a wall of the tube extends from the top side to the bottom side of the pad. 
     In some embodiments, the thermal conduction layer includes a skin contact surface configured to provide for breathability of the skin and the skin contact surface may be textured. 
     In some embodiments, the pad is configured to provide for visibility of the skin through the pad. At least a portion of the pad may be translucent. Each of the fluid containing layer and the thermal conduction layer may include a translucent portion, and the translucent portions may be coincident with each other. Each of the translucent portions may also be transparent. 
     The insulation layer may include at least one of an opening or translucent portion which may be disposed coincident with the translucent portions of the fluid containing layer and the thermal conduction layer. 
     The translucent portion of the insulation layer may include one or more air pockets, and in some embodiments, the translucent portion of the insulation layer is transparent. 
     In some embodiments, the pad includes a filter coupled to the fluid containing layer so that TTM fluid circulating through the fluid containing layer passes through the filter and the filter may include a porous wall disposed parallel to a continuous flow path through the filter. 
     Also disclosed herein is a method of providing a targeted temperature management (TTM) therapy to a patient. The method includes providing a TTM system including a TTM module configured to provide a TTM fluid, a thermal pad configured to receive the TTM fluid from the TTM module to facilitate thermal energy transfer between the TTM fluid and a patient, and a fluid delivery line (FDL) extending between the TTM module and the thermal pad, the FDL configured to provide TTM fluid flow between the TTM module and the thermal pad. 
     The thermal pad includes a top side, bottom side, and a fluid containing layer disposed between the top side and the bottom side. The fluid containing layer is configured for containing the TTM fluid and includes a fluid inlet and a fluid outlet, where the TTM fluid is circulatable within the fluid containing layer from the fluid inlet to the fluid outlet. The thermal pad further includes an insulation layer disposed the top side and a thermal conduction layer disposed on the bottom side. 
     The method further includes applying the thermal pad to the patient, delivering the TTM fluid from the TTM module to the thermal pad, and visually observing the skin through a translucent portion of the thermal pad. The method may further include passing TTM fluid through a filter coupled to the fluid containing layer. In some embodiments, the thermal pad further includes a chamfered edge extending along a perimeter of the thermal pad. In other embodiments, the thermal pad further includes a rounded edge extending along a perimeter of the thermal pad. The thermal conduction layer may include a textured bottom surface to facilitate breathability of the skin beneath the thermal pad. In some embodiments, at least a portion of the thermal pad is translucent and the method further includes visually observing the skin through the translucent portion. 
     Also disclosed herein is a medical pad for exchanging thermal energy between a targeted temperature management (TTM) fluid and a patient. The pad includes a top side and a bottom side. The pad further includes a fluid containing layer disposed between the top side and the bottom side, wherein the fluid containing layer is configured for containing the TTM fluid. The fluid containing layer includes a fluid inlet and a fluid outlet and the TTM fluid is circulatable within the fluid containing layer from the fluid inlet to the fluid outlet. The pad further includes an insulation layer disposed the top side, and a thermal conduction layer disposed on the bottom side. In use, the pad is disposed in contact with a skin of a patient, and the pad is configured to provide for visibility of the skin through the pad. 
     At least a portion of the pad may be translucent. Each of the fluid containing layer and the thermal conduction layer may include a translucent portion, and the translucent portions may be coincident with each other. Each of the translucent portions may also be transparent. 
     The insulation layer may include at least one of an opening or translucent portion which may be disposed coincident with the translucent portions of the fluid containing layer and the thermal conduction layer. 
     The translucent portion of the insulation layer may include one or more air pockets, and in some embodiments, the translucent portion of the insulation layer is transparent. 
     The pad may further include a chamfered edge extending along the perimeter of the pad, and in some embodiments, chamfered edge is a top edge of the pad. The pad may also include a rounded edge extending along the perimeter of the pad. The rounded edge may include a tube extending along the perimeter, a wall of the tube extends from the top side to the bottom side of the pad. 
     In some embodiments, the thermal conduction layer includes a skin contact surface configured to provide for breathability of the skin and the skin contact surface may be textured. 
     In some embodiments, the pad includes a filter coupled to the fluid containing layer so that TTM fluid circulating through the fluid containing layer passes through the filter and the filter may include a porous wall disposed parallel to a continuous flow path through the filter. 
     These and other features of the concepts provided herein will become more apparent to those of skill in the art in view of the accompanying drawings and the following description, which describe particular embodiments of such concepts in greater detail. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       A more particular description of the present disclosure will be rendered by reference to specific embodiments thereof that are illustrated in the appended drawings. It is appreciated that these drawings depict only typical embodiments of the invention and are therefore not to be considered limiting of its scope. Example embodiments of the invention will be described and explained with additional specificity and detail through the use of the accompanying drawings in which: 
         FIG. 1  illustrates a targeted temperature management (TTM) system for cooling or warming a patient, in accordance with some embodiments. 
         FIG. 2  illustrates a hydraulic schematic of the TTM system of  FIG. 1 , in accordance with some embodiments. 
         FIG. 3  illustrates a block diagram depicting various elements of a console of the TTM module of  FIG. 1 , in accordance with some embodiments. 
         FIG. 4A  is a top view of the thermal contact pad of  FIG. 1 , in accordance with some embodiments. 
         FIG. 4B  is a cross-sectional side view of the thermal contact pad of  FIG. 4A  cut along sectioning lines  4 B- 4 B, in accordance with some embodiments. 
         FIG. 4C  is a detail cross-sectional side view of a portion of the thermal contact pad of  FIG. 4A  cut along sectioning lines  4 C- 4 C illustrating an optional chamfered edge, in accordance with some embodiments. 
         FIG. 4D  is a detail cross-sectional side view of a portion of the thermal contact pad of  FIG. 4A  cut along sectioning lines  4 C- 4 C illustrating an optional rounded edge, in accordance with some embodiments. 
         FIG. 4E  is a bottom perspective view of thermal contact pad of  FIG. 4A  illustrating a textured bottom surface, in accordance with some embodiments. 
         FIG. 5A  is a top perspective view of an embodiment of the insulation layer of  FIG. 4B , in accordance with some embodiments. 
         FIG. 5B  is a top perspective view of another embodiment of the insulation layer of  FIG. 4B , in accordance with some embodiments. 
         FIG. 6A  is an exploded perspective view of a TTM fluid filter, in accordance with some embodiments. 
         FIG. 6B  is a cross-sectional side view of the filter of  FIG. 6A , in accordance with some embodiments. 
         FIG. 6C  is a side cross-sectional view of the thermal contact pad of  FIG. 1  incorporating the filter of  FIG. 6A , in accordance with some embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     Before some particular embodiments are disclosed in greater detail, it should be understood that the particular embodiments disclosed herein do not limit the scope of the concepts provided herein. It should also be understood that a particular embodiment disclosed herein can have features that can be readily separated from the particular embodiment and optionally combined with or substituted for features of any of a number of other embodiments disclosed herein. 
     Regarding terms used herein, it should also be understood the terms are for the purpose of describing some particular embodiments, and the terms do not limit the scope of the concepts provided herein. Ordinal numbers (e.g., first, second, third, etc.) are generally used to distinguish or identify different features or steps in a group of features or steps, and do not supply a serial or numerical limitation. For example, “first,” “second,” and “third” features or steps need not necessarily appear in that order, and the particular embodiments including such features or steps need not necessarily be limited to the three features or steps. Labels such as “left,” “right,” “top,” “bottom,” “front,” “back,” and the like are used for convenience and are not intended to imply, for example, any particular fixed location, orientation, or direction. Instead, such labels are used to reflect, for example, relative location, orientation, or directions. Singular forms of “a,” “an,” and “the” include plural references unless the context clearly dictates otherwise. The words “including,” “has,” and “having,” as used herein, including the claims, shall have the same meaning as the word “comprising.” Furthermore, the terms “or” and “and/or” as used herein are to be interpreted as inclusive or meaning any one or any combination. As an example, “A, B or C” or “A, B and/or C” mean “any of the following: A; B; C; A and B; A and C; B and C; A, B and C.” An exception to this definition will occur only when a combination of elements, components, functions, steps or acts are in some way inherently mutually exclusive. 
     The phrases “connected to” and “coupled to” refer to any form of interaction between two or more entities, including mechanical, electrical, magnetic, electromagnetic, fluid, signal, communicative (including wireless), and thermal interaction. Two components may be connected or coupled to each other even though they are not in direct contact with each other. For example, two components may be coupled to each other through an intermediate component. 
     Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art. 
       FIG. 1  illustrates a targeted temperature management (TTM) system  100  connected to a patient  50  for administering targeted temperature management therapy to the patient  50  which may include a cooling and/or warming of the patient  50 , in accordance with some embodiments. The TTM system  100  includes a TTM module  110  including a graphical user interface (GUI)  115  enclosed within a module housing  111 . The TTM system  100  includes a fluid deliver line (FDL)  130  extending from the TTM module  110  to a thermal contact pad  120  to provide for flow of TTM fluid  112  between the TTM module  110  and the pad  120 . The FDL includes two conduits to facilitate delivery flow of TTM fluid  112  from the TTM module  110  to the pad  120  and return flow TTM fluid  112  from the pad  120  to the TTM module  110 . In some embodiments, the two conduits may be attached to each other along a portion of a length of the FDL. 
     The TTM system  100  may include 1, 2, 3, 4 or more pads  120  and the TTM system  100  may include 1, 2, 3, 4 or more fluid delivery lines  130 . In use, the TTM module  110  prepares the TTM fluid  112  for delivery to the pad  120  by heating or cooling the TTM fluid  112  to a defined temperature in accordance with a prescribed TTM therapy. The TTM module  110  circulates the TTM fluid  112  along a TTM fluid flow path including within the pad  120 . The pad  120  is applied to the skin  51  of the patient to facilitate thermal energy exchange between the pad  120  and the patient  50 . During the TTM therapy, the TTM module  110  may continually control the temperature of the TTM fluid  112  toward a target TTM temperature. 
     The FDL  130  includes at least a fluid delivery conduit  131  and a fluid return conduit  132 . In use, the TTM fluid  112  may flow from the TTM module  110  through the fluid delivery conduit  131  to the pad  120 . The TTM fluid  112  may then flow from thermal pad  120  through the fluid return conduit  132  to the TTM module  110 . In some embodiments, the fluid delivery conduit  131  and the fluid return conduit  132  may be attached together along a portion of a length of the FDL  130 . The fluid delivery conduit  131  and the fluid return conduit  132  may be separated from each other at each end of the FDL  130 . 
     The TTM system  100  may include a connector system  150  to couple the FDL  130  to the pad  120 . In some embodiments, the connector system  150  may couple a single fluid conduit of the FDL to the pad  120 . Hence, the connection between the FDL  130  and the pad  120  may include more than one connector system  150  to couple more than one fluid conduit to the pad  120 . The connector system  150  is further described below in  FIGS. 4A and 4B . 
       FIG. 2  illustrates a hydraulic schematic of the TTM system  100 . The FDL  130  and the pad  120  are disposed external to the housing  111  of the TTM module  110 . The TTM module includes various fluid sensors and fluid control devices to prepare and circulate the TTM fluid  112 . The fluid subsystems of the TTM module may include a temperature control subsystem  210  and a circulation subsystem  230 . 
     The temperature control subsystem  210  may include a chiller pump  211  to pump (recirculate) TTM fluid  112  through a chiller circuit  212  that includes a chiller  213  and a chiller tank  214 . A temperature sensor  215  within the chiller tank  214  is configured to measure a temperature of the TTM fluid  112  within the chiller tank  214 . The chiller  213  may be controlled by a temperature control logic (see  FIG. 3 ) as further described below to establish a desired temperature of the TTM fluid  112  within chiller tank  214 . In some instances, the temperature of the TTM fluid  112  within the chiller tank  214  may be less than the target temperature for the TTM therapy. 
     The temperature control subsystem  210  may further include a mixing pump  221  to pump TTM fluid  112  through a mixing circuit  222  that includes the chiller tank  214 , a circulation tank  224 , and a dam  228  disposed between the chiller tank  214  and circulation tank  224 . The TTM fluid  112 , when pumped by the mixing pump  221 , enters the chiller tank  214  and mixes with the TTM fluid  112  within the chiller tank  214 . The mixed TTM fluid  112  within the chiller tank  214  flows over the dam  228  and into the circulation tank  224 . In other words, the mixing circuit  222  mixes the TTM fluid  112  within chiller tank  214  with the TTM fluid  112  within circulation tank  224  to cool the TTM fluid  112  within the circulation tank  224 . A temperature sensor  225  within the circulation tank  224  measures the temperature of the TTM fluid  112  within the circulation tank  224 . The temperature control logic may control the mixing pump  221  in accordance with temperature data from the temperature sensor  225  within the circulation tank  224 . 
     The circulation tank  224  includes a heater  227  to increase to the temperature of the TTM fluid  112  within the circulation tank  224 , and the heater  227  may be controlled by the temperature control logic. In summary, the temperature control logic when executed by the processor (see  FIG. 3 ) may  1 ) receive temperature data from the temperature sensor  215  within the chiller tank and the temperature sensor  225  within the circulation tank  224  and  2 ) control the operation of the chiller  213 , the chiller pump  211 , the heater  227 , and mixing pump  222  to establish and maintain the temperature of the TTM fluid  112  within the circulation tank  224  at the target temperature for the TTM therapy. 
     The circulation subsystem  230  includes a circulation pump  213  to pull TTM fluid  112  from the circulation tank  224  and through a circulating circuit  232  that includes the fluid delivery line  130  and the pad  120  located upstream of the circulation pump  213 . The circulating circuit  232  also includes a pressure sensor  237  to represent a pressure of the TTM fluid  112  within the pad  120 . The circulating circuit  232  includes a temperature sensor  235  within the circulation tank  224  to represent the temperature of the TTM fluid  112  entering the pad  120  and a temperature sensor  236  to represent the temperature of the TTM fluid exiting the pad  120 . A flow meter  238  is disposed downstream of the circulation pump  213  to measure the flow rate of TTM fluid  112  through the circulating circuit  232  before the TTM fluid  112  re-enters that the circulation tank  224 . 
     In use, the circulation tank  224 , which may be vented to atmosphere, is located below (i.e., at a lower elevation than) the pad  120  so that a pressure within the pad  120  is less than atmospheric pressure (i.e., negative) when TTM fluid flow through the circulating circuit  232  is stopped. The pad  120  is also placed upstream of the circulation pump  231  to further establish a negative pressure within the pad  120  when the circulation pump  213  is operating. The fluid flow control logic (see  FIG. 3 ) may control the operation of the circulation pump  213  to establish and maintain a desired negative pressure within the pad  120 . A supply tank  240  provides TTM fluid  112  to the circulation tank  224  via a port  241  to maintain a defined volume of TTM fluid  112  within the circulation tank  224 . 
       FIG. 3  illustrates a block diagram depicting various elements of the TTM module  110  of  FIG. 1 , in accordance with some embodiments. The TTM module  110  includes a console  300  including a processor  310  and memory  340  including non-transitory, computer-readable medium. Logic modules stored in the memory  340  include patient therapy logic  341 , fluid temperature control logic  342 , and fluid flow control logic  343 . The logic modules when executed by the processor  310  define the operations and functionality of the TTM Module  110 . 
     Illustrated in the block diagram of  FIG. 3  are fluid sensors  320  as described above in relation to  FIG. 2 . Each of the fluid sensors  320  are coupled to the console  300  so that data from the fluid sensors  320  may be utilized in the performance of TTM module operations. Fluid control devices  330  are also illustrated in  FIG. 3  as coupled to the console  300 . As such, logic modules may control the operation of the fluid control devices  330  as further described below. 
     The patient therapy logic  341  may receive input from the clinician via the GUI  115  to establish operating parameters in accordance with a prescribed TTM therapy. Operating parameters may include a target temperature for the TTM fluid  112  and/or a thermal energy exchange rate which may include a time-based target temperature profile. In some embodiments, the fluid temperature control logic  342  may define other fluid temperatures of the TTM fluid  112  within the TTM module  110 , such a target temperature for the TTM fluid  112  within the chiller tank  214 , for example. 
     The fluid temperature control logic  342  may perform operations to establish and maintain a temperature of the TTM fluid  112  delivered to the pad  120  in accordance with the predefined target temperature. One temperature control operation may include chilling the TTM fluid  112  within the chiller tank  214 . The fluid temperature control logic  342  may utilize temperature data from the chiller tank temperature sensor  215  to control the operation of the chiller  213  to establish and maintain a temperature of the TTM fluid  112  within the chiller tank  214 . 
     Another temperature control operation may include cooling the TTM fluid  112  within the circulation tank  224 . The fluid temperature control logic  342  may utilize temperature data from the circulation tank temperature sensor  225  to control the operation of the mixing pump  221  to decrease the temperature of the TTM fluid  112  within the circulation tank  224  by mixing TTM fluid  112  from the chiller tank  214  with TTM fluid  112  within circulation tank  224 . 
     Still another temperature control operation may include warming the TTM fluid  112  within the circulation tank  224 . The fluid temperature control logic  342  may utilize temperature data from the circulation tank temperature sensor  225  to control the operation of the heater  227  to increase the temperature of the TTM fluid  112  within the circulation tank  224 . 
     The fluid flow control logic  343  may control the operation of the circulation pump  231 . As a thermal energy exchange rate is at least partially defined by the flow rate of the TTM fluid  112  through the pad  120 , the fluid flow control logic  343  may, in some embodiments, control the operation of the circulation pump  231  in accordance with a defined thermal energy exchange rate for the TTM therapy. 
     The console  300  may include or be couple do wireless communication module  350  to facilitate wireless communication with external devices. A power source  360  provides electrical power to the console  300 . 
       FIG. 4A  shows a top view of the pad  120  in accordance with some embodiments. The pad  120  includes a top surface  401 , bottom surface  402 , and an outside edge  403  extending along a circumference of the pad  120 . In the illustrated embodiment, the pad  120  includes two connector systems  150  coupled to the FDL  130 . As illustrated, the connector systems  150  may provide for a rotatable connection between the FDL  130  and the pad  120 . The rotatable connection may provide for the FDL  130 , or more specifically each of the fluid delivery conduit  131  and the fluid return conduit  132 , to rotate through an angle  455  ranging up to about 90 degrees, 180 degrees, or 360 degrees. 
       FIG. 4B  shows a cross-sectional side view of the pad  120  in contact with the skin  51 , in accordance with some embodiments. As shown, the connector system  150  may include an elbow  460  to change the direction of FDL  130  extending away from the connector system  150 . As shown, the direction of FDL  130  is shifted from a direction perpendicular to the pad  120  to a direction that is substantially parallel to the pad  120 . The elbow  450  also establishes an orientation of a distal portion  461  of the FDL  130  to be substantially parallel to the pad  120  and/or the fluid containing layer  420 . The fluid containing layer  420  may include one or more internal fluid conduits  426  fluidly coupled to the FDL  130  and the TTM fluid  112  may flow through the internal fluid conduits  426 . 
     The pad  120  includes multiple layers to provide for multiple functions of the pad  120 . A fluid containing layer  420  is shown fluidly coupled to the fluid delivery conduit  131  of the FDL  130  to facilitate circulation of the TTM fluid  112  within the fluid containing layer  420 . The fluid containing layer  420 , having TTM fluid  112  circulating therein, defines a heat sink or a heat source for the patient  50  in accordance with a temperature of the TTM fluid  112 . The fluid containing layer  420 , or a portion thereof, may be formed of translucent materials so that the fluid containing layer  420 , or the portion thereof, is translucent from the top side  421  to the bottom side  422 . In other embodiments, the fluid containing layer  420 , or a portion thereof, may be formed of transparent materials so that the fluid containing layer  420 , or the portion thereof, is transparent from the top side  421  to the bottom side  422 . 
     The pad  120  includes a thermal conduction layer  430  disposed between the fluid containing layer  420  and the patient&#39;s skin  51 . The thermal conduction layer  430  is configured to facilitate thermal energy exchange between the fluid containing layer  420  and the patient  50 . The thermal conduction layer  430  may be attached to the fluid containing layer  420  along a bottom surface  421  of the fluid containing layer  420 . The thermal conduction layer  430  may be conformable to provide for intimate thermal contact with the patient  50 . In other words, thermal conduction layer  430  may conform to a contour of the patient  50  to facilitate thermal energy exchange between the thermal conduction layer  430  and the patient  50 . 
     The thermal conduction layer  430 , or a portion thereof, may be formed of translucent materials so that the thermal conduction layer  430 , or the portion thereof, is translucent from the bottom side  422  of the fluid containing layer  420  to the bottom side  402  of the pad  120 . In other embodiments, the thermal conduction layer  430 , or a portion thereof, may be formed of transparent materials so that the thermal conduction layer  430 , or the portion thereof, is transparent from the bottom side  422  of the fluid containing layer  420  to the bottom side  402  of the pad  120 . 
     The pad  120  includes an insulation layer  410  disposed on the top side of the fluid containing layer  420 . The insulation layer  410  is configured to inhibit thermal energy transfer between the fluid containing layer  420  and the environment. The insulation layer  410  may be attached to the fluid containing layer  420  along a top surface  422  of the fluid containing layer  420 . In some embodiments, the insulation layer  410  may include one or more openings  411  extending through the insulation layer  410  to provide for coupling of the FDL  130  with the fluid containing layer  420 . 
     The insulation layer  410 , or a portion thereof, may be formed of translucent materials so that the insulation layer  410 , or the portion thereof, is translucent from the top side  401  of the pad  120  to the top side  421  of the fluid containing layer  420 . In other embodiments, the insulation layer  410 , or a portion thereof, may be formed of transparent materials so that the insulation layer  410 , or the portion thereof, is transparent from the top side  401  of the pad  120  to the top side  421  of the fluid containing layer  420 . 
       FIG. 4C  is a cross-sectional side view of an embodiment of the pad  120  cut along sectioning lines  4 C- 4 C. In the illustrated embodiment, the pad  120  includes a top chamfer  405  and a bottom chamfer  406  extending along a perimeter of the pad  120 . The top chamfer  405  and the bottom chamfer  406  may add flexibility to the pad  120  along the perimeter to reduce pressure contact points and/or abrasion contact points of the pad  120  on the skin  51 . As such, the top chamfer  406  and/or the bottom chamfer  405  may inhibit skin irritation of the patient  50  along the perimeter of the pad  120 . The top chamfer  406  and/or the bottom chamfer  405  may also allow the clinician to visually observe the skin  51  along the perimeter beneath the pad  120 . In some embodiments, the top chamfer  405  and a bottom chamfer  406  may extend around the entire circumference of the pad  120 . In other embodiments, the top chamfer  405  and a bottom chamfer  406  may extend along one or more perimeter sections of the circumference. In some embodiments, either one of the top chamfer  405  or the bottom chamfer  406  may be omitted. 
       FIG. 4D  is a cross-sectional side view of another embodiment of the pad  120  cut along sectioning lines  4 C- 4 C. In this illustrated embodiment, the pad  120  includes a rounded perimeter edge  407  of the pad  120 . The rounded perimeter edge  407  may include a tube  408  having a wall  409  that is cut lengthwise along a length of the tube  408 . The tube  408  may be attached to the pad  120  such that the wall  409  extends around the outside edge  403  of the pad  120  from the top side  401  to the bottom side  402  of the pad  120 . The rounded edge  407  may reduce pressure contact points and/or abrasion contact points of the pad  120  on the skin  51 . As such, the rounded perimeter edge  407  may inhibit skin irritation of the patient  50  along the rounded perimeter edge  407 . In some embodiments, rounded perimeter edge  407  may extend around the entire circumference of the pad  120 . In other embodiments, the rounded perimeter edge  407  may extend along one or more perimeter sections of the circumference. 
       FIG. 4E  is a perspective bottom view of the pad  120  showing a textured bottom surface  432  of the thermal conduction layer  430 . The textured bottom surface  432  may be configured to provide for breathability of the skin  51  when the pad  120  is applied to the skin  51 . The textured bottom surface  432  may facilitate breathability of the skin  51  while maintaining thermal energy exchange between fluid containing layer  420  and the patient  50 . The bottom surface  432  may include multiple protrusions and/or depressions that provide for airflow between the skin  51  and the thermal conduction layer  630 . The protrusions may include any structure extending away from the surface, such as ribs or bumps, for example. The depressions may include any structure that is depressed from surface such as troughs or dimples, for example. In some embodiments, the textured bottom surface  432  may include a layer component (e.g., a fabric mesh) to provide for breathability of the skin  51 . 
       FIG. 5A  is a top perspective view of an insulation layer  510  that may be included with the pad  120 . The insulation layer  510  can, in certain respects, resemble components of the insulation layer  410 . It will be appreciated that all the illustrated embodiments may have analogous features. Relevant disclosure set forth above regarding similarly identified features thus may not be repeated hereafter. However, such features may clearly be the same, or substantially the same, as features depicted in other embodiments and/or described with respect to such embodiments. 
     The insulation layer  510  includes a translucent portion  512 . The translucent portion  512  may be formed of translucent materials and may include multiple air pockets  513  (e.g., enclosed in translucent plastic) that establish thermal insulative properties of the insulation layer  510  while maintaining translucence. In some embodiments, the translucent portion  512  may include the entire insulation layer  510 . In other embodiments, the insulation layer  510  may include multiple translucent portions  512 . The translucent portion  512  may, in combination with the translucence of the fluid containing layer  420  and the thermal conduction layer  430 , provide for visibility of the skin  51  through the pad  120 . In other embodiments, the translucent portion  512  may be transparent (e.g., the multiple air pockets  513  enclosed within transparent plastic) so that in combination with the transparency of the fluid containing layer  420  and the thermal conduction layer  430 , the pad  120  may provide for transparent visibility of the skin  51  through the pad  120 . 
       FIG. 5B  is a top perspective view of an insulation layer  515  that may be included with the pad  120 . The insulation layer  515  includes one or more openings  516  extending through the insulation layer  515 . The openings  516  may be configured to provide for visibility through the insulation layer  515 . The one or more openings  516  may, in combination with the translucence of the fluid containing layer  420  and the thermal conduction layer  430 , provide for visibility of the skin  51  through the pad  120 . 
     By way of summary, in some embodiments, at least a portion of each layer of the pad  120  may be configured for visibility therethrough. In such embodiments, the pad  120  may be formed so that the individual visibility portions of the layers are aligned coincidently with each other. As such, at least a portion of the pad  120  may be configured for translucent and/or transparent visibility therethrough. 
       FIGS. 6A and 6B  show a filter  600  that may be included with the TTM system  100 . The filter  600  may be disposed in line with a TTM fluid flow path of the TTM system  100  so that the circulating TTM fluid  112  flows through the filter  600 . The filter  600  may be configured to remove (i.e., filter out) material/particles having a size of 0.2 microns or larger from the TTM fluid  112  without causing a flow restriction of the TTM fluid  112 . 
     The filter  600  includes a longitudinal shape having a flow path  601  extending from a first end  602  to a second end  603 . The filter  600  includes a diffuser  610  adjacent the first end  602 , a nozzle adjacent  620  the second end  603 , and a body  630  extending between the diffuser  610  and the nozzle  620 . Along the diffuser  610 , a cross-sectional flow area of the filter  600  expands from an inlet flow area  611  to a body flow area  631  and along the nozzle  620 , the cross-sectional flow area of the filter  600  contracts from the body flow area  631  to an outlet flow area  621 . In some embodiments, the inlet flow area  611  and the outlet flow area  621  may be substantially equal. 
     In some embodiments, the body flow area  631  may be constant along the body  630 . In other embodiments, the body flow area  631  may vary along a length of the body  630  such that the body flow area  631  is greater or less along middle portion of the body  630  than at the ends of the body  630 . In some embodiments, the body flow area  631  may be circular. 
     The filter  600  includes an inner tube  640  disposed within the body  630  extending along the length of body  630 . The inner tube  640  may be coupled to the diffuser  610  at a first inner tube end  641  so that TTM fluid  112  entering the filter  600  at the first end  602  also enters the inner tube  640  at the first inner tube end  641 . The inner tube  640  may be coupled to the nozzle  620  at a second inner tube end  642  so that TTM fluid  112  exiting the filter  600  at the second end  603  also exits the inner tube  640  at the second inner tube end  642 . 
     The inner tube  640  includes an inner tube flow area  645  extending the length of the inner tube  640 . The inner tube flow area  645  may be greater than the inlet flow area  611  and/or the outlet flow area  621 . The inner tube flow area  645  may be constant along the length of the inner tube  640 . In some embodiments, the inner tube flow area  645  may vary along the length of the inner tube  640 . In some embodiments, the inner tube  640  may include a circular cross section. The inner tube  640  and the body  630  may be configured so that the body flow area  631  includes a combination of the inner tube flow area  645  and an annular flow area  636 . 
     The inner tube  640  includes a porous a circumferential wall  647 . The porous wall  647  may be configured so that TTM fluid  112  may flow through the porous wall  647 , i.e., through the pores  648  of the porous wall  647 . Consequently, TTM fluid  112  may flow through the porous wall  647  from the inner tube flow area  645  to the annular flow area  636  and from the annular flow area  636  into the inner tube flow area  645 . 
     In use, the longitudinal velocity of the TTM fluid  112  may change along the length of the filter  600 . As the volumetric TTM fluid  112  flow through the filter is constant, the longitudinal velocity of the TTM fluid  112  may be at least partially defined by the flow areas of the filter  600  as described below. The TTM fluid  112  may enter the filter  600  at a first longitudinal velocity  651  and decrease along the diffuser so that the TTM fluid  112  enters the inner tube at a second velocity  652  less than the first longitudinal velocity  651 . At this point, a portion of the TTM fluid  112  may flow through the porous wall  647  from the inner tube flow area  645  into the annular flow area  636  to divide the fluid flow into a third velocity  653  within the inner tube flow area  645  and a fourth velocity  654  within the annular flow area  636 . The fourth velocity  654  may be less than the third velocity  653 . A portion of the TTM fluid  112  may then flow back into the inner tube flow area  645  from the annular flow area  636  to define a fifth velocity  655  along the inner tube flow area  645  which may be about equal to the second velocity  652 . The TTM fluid  112  may then proceed along the nozzle  620  to define a sixth velocity  656  exiting the filter  600 . In some embodiments, the first velocity  651  and the sixth velocity  656  may be about equal. 
     The filter  600  may be configured to remove harmful bacteria and viruses from the TTM fluid  112  using sedimentation principles. In use, the filter  600  may be oriented horizontally so that the direction of fluid flow through the filter  600  is perpendicular to a gravitational force  665 . In some instances, bacteria, viruses, and other particles within the TTM fluid  112  may have a greater density than the TTM fluid  112  and as such may be urged by the gravitational force  665  (i.e., sink) in a direction perpendicular to the fluid flow direction. In some instances, particles within the inner tube flow area  645  may sink toward and through the porous wall  647  into the annular flow area  636 . Particles within the annular flow area  636  may then sink toward an inside surface  631  of the body  630  and become trapped adjacent the inside surface  631 . The geometry of the filter  600  may be configured to allow 0.2-micron bacteria/virus particles to fall out of the flow of TTM fluid  112  and become trapped along the inside surface  631 . 
     In some embodiments, the filter  600  may be configured so that flow of TTM fluid  112  from the inner tube flow area  645  into the annual flow area  636  may drag particles through the porous wall  647 . In some embodiments, the inlet flow area  611 , the inner tube flow area  645 , and the annual flow area  636  may be sized so that the third velocity  1053  is less than about 50 percent, 25 percent, or 10 percent of the first velocity  651  or less. In some embodiments, the body  630  and the inner tube  640  may be configured so that the fourth velocity  654  is less than the third velocity  653 . In some embodiments, the fourth velocity  654  may less than about 50 percent, 25 percent, or 10 percent of the third velocity  653  or less. 
     In some embodiments, the filter  600  may be configured so that the flow within the inner tube flow area  645  is laminar flow, i.e., so that the velocity of the fluid flow adjacent to or in close proximity to an inside surface  641  of the porous wall  647  is less than the velocity at a location spaced away from the inside surface  641 . In such an embodiment, the particles may more readily sink toward and through the porous wall  647 . 
     In some embodiments, the filter  600  may be configured so that the fluid flow within the annual flow area  636  is laminar flow, i.e., so that the velocity of the fluid flow adjacent to or in close proximity to inside surface  631  of the body  630  is less than the velocity at a location spaced away from the inside surface  631 . In such an embodiment, the particles may more readily sink toward and be trapped along the inside surface  631 . 
     The filter  600  may include three components including the inner tube  640  an inner body shell  638 , and an outer body shell  639 . Each of the three components may be formed via the plastic injection molding process. Assembly of the filter  600  may include capturing the inner tube  640  within the inner body shell  638  and the outer body shell  639  and sliding the inner body shell  638  into the outer body shell  639  wherein the fit between the inner body shell  638  and the outer body shell  639  is an interference fit. 
     In some embodiments, the filter  600  may be disposed within the pad  120 .  FIG. 6C  shows a detail cross-sectional view of the pad  120  including the filter  600  disposed within the fluid containing layer  420 . The filter  600  is coupled in line with the internal fluid conduit  426  within the fluid containing layer  420  so that TTM fluid  12  circulating within the pad  120  passes through the filter  600 . The filter  600  may be sized so that the inlet flow area  611  and the outlet flow area  621  are similar to a cross-sectional flow area of the internal flow path  660  within the fluid containing layer  420 . 
     In some embodiments, a thickness of the fluid containing layer  420  may increase adjacent the filter  600  to accommodate a body diameter  664  of the filter  600 . To further accommodate the body diameter  664 , the insulation layer  410  and/or the thermal conduction layer  430  may include internal depressions  662 ,  663 , respectively. 
     In some embodiments, one or more filters  600  may be disposed in line with the flow of TTM fluid  112  at other locations of the TTM system  100 . In some embodiments, one or more filters  600  may be disposed within the TTM module  110 . In some embodiments, one or more filters  600  may be disposed in line with the FDL  130 . In some embodiments, the filter  600  may be disposed in line with a fluid conduit of the pad external to the fluid containing layer  420  such as a conduit extending between the pad connector  652  and the pad  120 . 
     Without further elaboration, it is believed that one skilled in the art can use the preceding description to utilize the invention to its fullest extent. The claims and embodiments disclosed herein are to be construed as merely illustrative and exemplary, and not a limitation of the scope of the present disclosure in any way. It will be apparent to those having ordinary skill in the art, with the aid of the present disclosure, that changes may be made to the details of the above-described embodiments without departing from the underlying principles of the disclosure herein. In other words, various modifications and improvements of the embodiments specifically disclosed in the description above are within the scope of the appended claims. Moreover, the order of the steps or actions of the methods disclosed herein may be changed by those skilled in the art without departing from the scope of the present disclosure. In other words, unless a specific order of steps or actions is required for proper operation of the embodiment, the order or use of specific steps or actions may be modified. The scope of the invention is therefore defined by the following claims and their equivalents.