Thermal pad with enhanced heat transfer characteristics
Disclosed is a medical pad for exchanging thermal energy between a targeted temperature management (TTM) fluid and a patient. The pad includes a fluid channel extending between a fluid inlet and a fluid outlet, and a bottom channel wall that is disposed between the fluid and the patient during use of the pad. The wall is formed of a material having a thermal conductivity, and the wall includes elements embedded within the wall. The elements are formed of a material having a greater thermal conductivity than the wall material so that a composite thermal conductivity of the wall that is greater than the thermal conductivity of the wall material alone. The thermal energy exchange between the fluid and the patient is defined in accordance with the composite thermal conductivity. The pad can include channel shapes and features that enhance the heat transfer convection coefficient of the fluid within the channel.
1 . A medical pad for exchanging thermal energy between a targeted temperature management (TTM) fluid and a patient, the medical pad comprising:
a fluid channel extending between a fluid inlet positioned at a perimeter edge of the medical pad and a fluid outlet centrally positioned on the medical pad, wherein the fluid channel defines a spiral shape converging radially inward from the fluid inlet toward the fluid outlet, and
a bottom channel wall disposed between the TTM fluid and the patient during use of the medical pad, the bottom channel wall having an inner surface in contact with the TTM fluid and an outer surface in contact with the patient, the inner surface and the outer surface defining a thickness of the bottom channel wall, wherein:
the bottom channel wall (i) is formed of a material having a first thermal conductivity and (ii) includes elements embedded within the bottom channel wall, the elements formed of a material having a second thermal conductivity to define a composite thermal conductivity of the bottom channel wall that is greater than the first thermal conductivity, and
thermal energy exchange between the TTM fluid and the patient is defined in accordance with the composite thermal conductivity.
2 . The medical pad according to claim 1 , wherein the elements include one or more of particles, nano-particles, composites, fibers, fluid pockets, bars extending across the thickness of the bottom channel wall, or layers extending along the bottom channel wall.
3 . The medical pad according to claim 1 , wherein:
centrifugal acceleration of a fluid flow within the fluid channel induces turbulence of the fluid flow within the fluid channel,
the induced turbulence defines a first enhancement of a convection coefficient of the TTM fluid with respect to the bottom channel wall, and
the thermal energy exchange between the TTM fluid and the patient is defined in accordance with the convection coefficient including the first enhancement.
4 . The medical pad according to claim 3 , wherein:
the fluid channel comprises at least one pair of channel walls extending along the fluid channel,
the at least one pair of channel walls face each other from opposite sides of the fluid channel,
the fluid channel further comprises a plurality of wall segments extending across at least a majority of the fluid channel,
a first subset of the plurality of wall segments extends away from one of the at least one pair of channel walls,
a second subset of the plurality of wall segments extends away from the other of the pair of channel walls, and
each wall segment of the second subset is disposed between adjacent wall segments of the first subset.
5 . The medical pad according to claim 4 , wherein:
fluid flow between the plurality of wall segments induces turbulence of the fluid flow within the fluid channel,
the induced turbulence defines a second enhancement of the convection coefficient of the TTM fluid with respect to the bottom channel wall, and
the thermal energy exchange between the TTM fluid and the patient is defined in accordance with the convection coefficient including the second enhancement.
6 . The medical pad according to claim 1 , wherein:
the fluid channel comprises a plurality of inward protruding ribs disposed along one or more walls of the fluid channel,
the plurality of inward protruding ribs are disposed at an angle with respect to the fluid channel,
the plurality of inward protruding ribs induce a swirling turbulence of a fluid flow along the fluid channel,
the swirling turbulence defines a third enhancement of a convection coefficient of the TTM fluid with respect to the bottom channel wall, and
the thermal energy exchange between the TTM fluid and the patient is defined in accordance with the convection coefficient including the third enhancement.
7 . The medical pad according to claim 1 , further comprising:
a first pad portion defining a first patient contact area; and
a separate second pad portion defining a second patient contact area,
wherein the separate second pad portion is directly coupleable with the first pad portion to define a combined patient contact area equaling a sum of the first patient contact area and the second patient contact area.
8 . The medical pad according to claim 1 , wherein a patient contact area of the medical pad includes:
a first patient contact area defined by a first pad portion; and
a second patient area defined by a second pad portion,
wherein the second pad portion is separable from the first pad portion to define a reduced patient contact area equaling the first patient contact area.
9 . A method of providing a targeted temperature management (TTM) therapy to a patient, comprising:
applying a thermal contact pad to the patient,
altering a patient contact area of the thermal contact pad to accommodate a size of the patient,
establishing a flow of TTM fluid through the thermal contact pad by directing TTM fluid flow along a fluid channel to enhance a heat transfer convection coefficient of the thermal contact pad, wherein the fluid channel defines a spiral shape converging radially inward from a fluid inlet positioned at a perimeter edge of the thermal contact pad toward a fluid outlet centrally positioned on the thermal contact pad; and
exchanging thermal energy with the patient through a bottom wall of the thermal contact pad, wherein:
the bottom wall is disposed between the TTM fluid and the patient during use of the thermal contact pad,
the bottom wall has an inner surface in contact with the TTM fluid and an outer surface in contact with the patient, and
the bottom wall comprises embedded elements configured to enhance a thermal conductivity of the bottom wall.
10 . The method according to claim 9 , wherein altering the patient contact area comprises coupling a second thermal contact pad to the thermal contact pad to increase the patient contact area.
11 . The method according to claim 9 , wherein altering the patient contact area comprises removing a separable portion of the thermal contact pad from the thermal contact pad to decrease the patient contact area to an area defined by a remaining portion of the thermal contact pad.
12 . The method according to claim 9 , wherein:
the fluid channel comprises at least one pair of channel walls extending along the fluid channel,
the channel walls face each other from opposite sides of the fluid channel,
the fluid channel further comprises a plurality of wall segments extending across at least a majority of the fluid channel,
a first subset of the plurality of wall segments extends away from one of the at least one pair of channel walls,
a second subset of the plurality of wall segments extends away from the other a second of the at least one pair of channel walls, and
each wall segment of the second subset is disposed between adjacent wall segments of the first subset.
13 . A medical pad for exchanging thermal energy between a targeted temperature management (TTM) fluid and a patient, the medical pad comprising:
a fluid channel extending between a fluid inlet and a fluid outlet, wherein:
the fluid channel defines a double spiral shape comprising:
a first channel portion converging radially inward from the fluid inlet disposed at a perimeter edge of the medical pad toward a central location;
a second channel portion expanding radially outward from the central location toward an outlet disposed at the perimeter edge of the medical pad; and
a fluid connection at the central location between the first channel portion and the second channel portion, and
the second channel portion is disposed between adjacent wraps of the first channel portion; and
a bottom channel wall disposed between the TTM fluid and the patient during use of the medical pad, the bottom channel wall having an inner surface in contact with the TTM fluid and an outer surface in contact with the patient, the inner surface and the outer surface defining a thickness of the bottom channel wall, wherein:
the bottom channel wall (i) is formed of a material having a first thermal conductivity and (ii) includes elements embedded within the bottom channel wall, the elements formed of a material having a second thermal conductivity to define a composite thermal conductivity of the bottom channel wall that is greater than the first thermal conductivity, and
thermal energy exchange between the TTM fluid and the patient is defined in accordance with the composite thermal conductivity.
14 . The medical pad according to claim 13 , wherein a fluid flow in the first channel portion and the second channel portion is in opposite directions.
15 . The medical pad according to claim 13 , wherein:
centrifugal acceleration of a fluid flow within the fluid channel induces turbulence of the fluid flow within the fluid channel,
the induced turbulence defines a first enhancement of a convection coefficient of the TTM fluid with respect to the bottom channel wall, and
the thermal energy exchange between the TTM fluid and the patient is defined in accordance with the convection coefficient including the first enhancement.
16 . The medical pad according to claim 13 , wherein:
the fluid channel comprises at least one pair of channel walls extending along the fluid channel,
the channel walls face each other from opposite sides of the fluid channel,
the fluid channel further comprises a plurality of wall segments extending across at least a majority of the fluid channel,
a first subset of the plurality of wall segments extends away from one of the at least one pair of channel walls,
a second subset of the plurality of wall segments extends away from the other a second of the at least one pair of channel walls, and
each wall segment of the second subset is disposed between adjacent wall segments of the first subset.
17 . The medical pad according to claim 16 , wherein:
fluid flow between the plurality of wall segments induces turbulence of the fluid flow within the fluid channel,
the induced turbulence defines a second enhancement of a convection coefficient of the TTM fluid with respect to the bottom channel wall, and
the thermal energy exchange between the TTM fluid and the patient is defined in accordance with the convection coefficient including the second enhancement.
18 . The medical pad according to claim 13 , wherein:
the fluid channel comprises a plurality of inward protruding ribs disposed along one or more walls of the fluid channel,
the plurality of inward protruding ribs are disposed at an angle with respect to the fluid channel,
the plurality of inward protruding ribs induce a swirling turbulence of a fluid flow along the fluid channel,
the swirling turbulence defines a third enhancement of a convection coefficient of the TTM fluid with respect to the bottom channel wall, and
the thermal energy exchange between the TTM fluid and the patient is defined in accordance with the convection coefficient including the third enhancement.
19 . The medical pad according to claim 13 , further comprising:
a first pad portion defining a first patient contact area; and
a separate second pad portion defining a second patient contact area,
wherein the second separate pad portion is directly coupleable with the first pad portion to define a combined patient contact area equaling a sum of the first patient contact area and the second patient contact area.
20 . The medical pad according to claim 13 , wherein a patient contact area of the medical pad includes:
a first patient contact area defined by a first pad portion; and
a second patient area defined by a second pad portion,
wherein the second pad portion is separable from the first pad portion to define a reduced patient contact area equaling the first patient contact area.