Patent Grant
10842288
The present specification generally relates to person support systems, and more specifically, to person support systems having cooling features.
Conventionally, a subject may be positioned on a support surface during a medical procedure. The support surface is generally the upper surface of a surgical table, such as a spine table or standard operating room (OR) table, and may include a number of pads to provide support to the subject. The pads provide cushioning to the subject and may facilitate positioning the subject so as to provide access to a portion of the subject's anatomy that is to be operated on. For example, in the case of a spine table, the pads of the support surface may be used to position the subject on the spine table such that the subject's spine is curved or arched, thereby separating the vertebrae.
During a surgical operation the subject may be maintained in one position on the support surface for an extended period of time. As such, certain areas of the subject's anatomy in contact with the surface may be subject to relatively high, localized pressure. For example, when a subject is in a supine position on the surface, portions of the subject's posterior skin, such as the subject's sacral area, buttocks, scapular areas, and/or heels, may be subject to relatively high, localized pressure due to the subject's own body weight. These areas of localized pressure may be different depending on the orientation of the subject on the surface. For example, when the subject is in the prone position on the surface, the areas of localized pressure may be along the anterior skin of the subject. The localized pressure of contact of the skin with the surface deforms the tissue of the subject, which may cause deformation of blood vessels. If serious enough, it may result in a reduction in blood flow, reducing the amount of oxygen in the tissue. Lack of oxygen causes ischemia, which kills the tissue. Thus, the areas of relatively high localized pressure may be prone to the development of pressure injuries, also known as pressure ulcers, due to the localized pressure.
The development of pressure injuries may be further exacerbated by heat and the presence of moisture, such as perspiration, trapped between the skin and the surface for extended periods of time. In addition to subjecting the skin to pressure, the surface provides resistance to the flow of heat and moisture away from the skin. Therefore, contact of the skin with the surface results in an increased temperature and humidity environment of the skin in contact with the surface. As temperature increases, the metabolic demands of the tissue also increases (for example, it has been reported that each degree in temperature increase may increase the metabolic demands of tissue by about 10%—see Du Bois, E. F. “The Basal Metabolism in Fever,” The Journal of the American Medical Association, (1921), 77(5), pp. 352-55). As the temperature of skin tissue increases, resulting in an increase in the oxygen demand (metabolic demand), ischemia caused by reduced blood flow due to deformation of blood vessels in the tissue is enhanced, which increases the rate of development of pressure injuries. Thus, the combination of increased temperature of the skin tissue and the localized pressure of contact with the support surface further accelerates formation of pressure injuries in the subject.
Accordingly, a need exists for alternative person support systems, such as surgical tables or the like, which mitigate the development of pressure injuries in subjects positioned on the person support systems. According to one embodiment, A person support system may include a longitudinal frame comprising at least one side rail, a deck positioned on the longitudinal frame, the deck comprising a thermally conductive material, and a cooling source thermally coupled to the deck. The cooling source may draw heat from at least a portion of a top surface of the deck and through the deck thereby cooling the at least a portion of the top surface of the deck.
According to another embodiment, a cooling system for a person support system may include a reservoir or a heat transfer conduit thermally coupleable to a deck or a support pad of the person support system, a heat exchanger, a first fluid conduit in fluid communication with a heat exchanger inlet and a reservoir outlet or an outlet of the heat transfer conduit, and a second fluid conduit in fluid communication with a heat exchanger outlet and a reservoir inlet or an inlet of the heat transfer conduit. The reservoir or heat transfer conduit, the heat exchanger, the first fluid conduit, and the second fluid conduit may form a cooling circuit such that when a cooling fluid is disposed in the cooling circuit and the heat exchanger is positioned vertically higher than the reservoir of the heat transfer conduit, the cooling fluid may absorb heat from the deck or the support pad of the person support system, flow through the first fluid conduit to the heat exchanger, release heat in the heat exchanger, and flow through the second fluid conduit back to the reservoir or the heat transfer conduit.
Additional features and advantages will be set forth in the detailed description which follows, and in part will be readily apparent to those skilled in the art from that description or recognized by practicing the embodiments described herein, including the detailed description which follows, the claims, as well as the appended drawings.
It is to be understood that both the foregoing general description and the following detailed description describe various embodiments and are intended to provide an overview or framework for understanding the nature and character of the claimed subject matter. The accompanying drawings are included to provide a further understanding of the various embodiments, and are incorporated into and constitute a part of this specification. The drawings illustrate the various embodiments described herein, and together with the description serve to explain the principles and operations of the claimed subject matter.
Referring now to the illustrative examples in the drawings, wherein like numerals represent the same or similar elements throughout:
Referring to
In embodiments, the table top assembly 104 generally includes a longitudinal frame 125, a foot frame 107, and a head frame 108. The foot frame 107 may be pivotally and removably attached to the longitudinal frame 125. Similarly, the head frame 108 may be pivotally and removably attached to the longitudinal frame 125 opposite the foot frame 107 in the +/−X direction of the coordinate axes of
The longitudinal frame 125 of the person support system 101 depicted in
While
Referring to
Mild skin cooling has been shown to reduce the susceptibility of skin to breakdown. For example, mild skin cooling may be particularly effective in reducing skin breakdown in operating rooms and other applications in which relatively immobile subjects are placed on relatively firm surfaces for extended periods. (See, Du Bois, E. F., “The basal metabolism in fever,” Journal of the American Medical Association, (1921), 77(5), pp. 352-5. See also, Kokate, J. Y., Leland, K. J., Held, A. M., et al., “Temperature-Modulated Pressure Ulcers: A Porcine Model,” Arch Phys Med Rehabil, (1995), 76, pp. 666-673. See also, Iaizzo, P., “Temperature Modulation of Pressure Ulcer Formation: Using a Swine Model,” Wounds, (Dec. 20, 2004), 16(11). See also, Lachenbruch, C., Tzen, Y., Brienza, D., Karg, T., and Lachenbruch, P. A., “The relative contributions of interface pressure, shear stress, and skin temperature on ischemic induced reactive hyperemic response,” Ostomy Wound Management, (February 2015), 61(2), pp. 16-25.) Approximately 25% to 33% of reported pressure injuries acquired in the hospital are caused by care in the operating room during surgery. Of all facility-acquired pressure injuries not caused by medical devices (i.e., catheters and the like), about 57% of the ulcers form in pelvic region and 30% form in the heels of the subject. Thus, the pelvic (i.e., sacral and/or buttocks regions of the subject) and heel areas of the subject are a primary focus for the cooling the skin of the subject. It may not be necessary to cool other areas of the subject. Higher temperatures in the remainder of the subject's body may make cooling the heels and pelvic areas more comfortable or tolerable. The cushioned surfaces (i.e., support pad 130) of person support systems 900, such as an operating table for example, are designed to manage pressure on the areas of the body contacting the person support system 900, but the cushioned surfaces typically do not decrease the temperature of the skin. Often, the cushioned surfaces insulate the skin, which actually causes the temperature of the skin to increase.
The embodiments described herein provide person support systems 101 having cooling features for cooling the deck 150 of the person support system 101. Cooling the deck 150 of the person support system 101 may cool the skin of the subject supported thereon, which may assist in mitigating the development of pressure injuries in subjects supported by the person support system 101. The cooling features described herein may cool the skin of the subject to prevent pressure injuries without changing the current support surface cushions (i.e., support pad 130) of existing person support systems 900, such as the TRUMF operating tables previously described in this disclosure. Thus, incorporation of the cooling features for cooling the deck 150 of the person support system 101 does not require modification to the support pad 130 or other surgical surface directly under the subject. The cooling features described herein cool the deck 150, and thus the support pad 130 or other support structure on the deck 150, by incorporating active cooling sources to the support members (e.g., the side rails 126, 127, deck 150, of both) of the person support system 900 and, optionally, incorporating temperature sensing and control systems to create a closed-loop solution. Using the cooling features to cool the subject's skin to a safe temperature decreases the likelihood of skin breakdown at the highest peak pressures (i.e., in regions of the skin contacting the support pad 130, deck, or other part of the person support system 900). The cooling features described herein may reduce the occurrence of pressure injuries that occur in operating rooms.
Referring to
The support pad 130 may include a cover 136 which, in some embodiments, envelopes and encloses a core part 132 of the support pad 130. The cover 136 may be, for example and without limitation, a woven or non-woven fabric which, in some embodiments, includes a coating, such as a urethane coating, polyurethane coating, or the like, which seals at least the top surface 131 of the support pad 130 from moisture permeation and facilitates cleaning of the support pad 130. Alternatively, the cover 136 may be an elastomer, gel, or other protective material to protect the core part 132 of the support pad 130 from fluids and/or biological materials. For example, in embodiments, the cover 136 may be fluid impermeable, such that water and/or biological fluids do not pass through the cover 136 and contaminate the core part 132 of the support pad 130. Suitable materials for the cover 136 may include, for example, urethane, vinyl, nylon, Lycra material, other elastomeric materials, or combinations of these materials. It is contemplated that other materials may be used as a cover 136, provided that they do not degrade the radiolucency of the support pad 130. In some embodiments, the cover 136 may be removable and/or washable, enabling it to be changed and/or washed.
The core part 132 of the support pad 130 is disposed within the cover 136. The core part 132 may be formed from any type of material suitable for providing support to the subject support by the top surface 131 of the support pad 130 without producing unnecessarily high pressures on the subject. For example, the core part 132 can be a foam, gel, other material, or combinations thereof. Foam materials suitable for use as the core part 132 may include, but are not limited to, urethane foam, polyurethane foam, or the like. The core part 132 may also include a combination of different foam materials. For example, the core part 132 may include urethane foam or polyurethane foam with an additional layer of memory foam disposed over the urethane foam or the polyurethane foam. In some embodiments, the core part 132 may include a fluid-filled bladder. The fluid may be, for example, a liquid or gas. In still other embodiments, the core part 132 may include multiple layers of material. The layers may include the same materials or different materials, depending on the particular embodiment. For example, a layer of foam and a layer of gel may be employed, or two layers of foam may be employed. As with the cover 136, in various embodiments, the core part 132 may be made of radiolucent materials.
The core part 132 may be planar or contoured, depending on the specific use of the support pad 130. For example, the core part 132 may have a uniform thickness, as depicted in
Although the person support system 101 is depicted in
Still referring to
Alternatively, in other embodiments, the deck 150 may be formed from a material suitable for load bearing applications having thermally conductive elements incorporated therein. The thermally conductive elements may be particles, fibers, strips, nanotubes, or other structures. The thermally conductive elements may have a relatively high thermal conductivity (e.g., greater than about 40 W/m*K). The thermally conductive elements may include for example and without limitation, the following: metal particles or metal fibers formed from copper, alloys of copper, silver, alloys of silver, gold, alloys of gold, and the like; polymer fibers or strips, such as polymer fibers or strips formed from ultra-high molecular weight polyethylene, polypropylene, liquid crystalline polymer, polyphthalamide, polycarbonate, or the like; carbon nanotubes, fibers, filaments, particles, or the like; or combinations thereof. For example, in embodiments, the deck 150 may be in the form of a polymer plate having metal particulates or woven or non-woven metallic fibers disposed therein.
The deck 150 may be formed from carbon fiber composites when radiolucency is desired. More specifically, in various embodiments provided herein, the materials of various components of the person support systems 101 are radiolucent, or transparent to x-rays. Radiolucency, particularly in the area of the support pads 130 and the deck 150 enables x-ray and fluoroscopic imaging to be performed during surgical procedures without interference from the person support system. X-ray or fluoroscopic images may be taken with a device having a C-arm that includes portions above and below the subject on the person support system 101. The use of non-radiolucent materials can cause shadows or even obstructions in the x-ray or fluoroscopic images. Accordingly, in some embodiments, portions of the person support systems 101 described herein, such as the support pads 130, deck 150, side rails 126, 127, or the like, are formed from radiolucent materials. The deck 150 may include a bottom surface 152 and a top surface 154. The bottom surface 152 may be a bottom exterior surface of the deck 150. In some embodiments, the support pad 130 may be supported by and thermally coupled to the deck 150 through contact of the support pad 130 with the top surface 154 of the deck 150. Additionally, in some embodiments, a portion of the bottom surface 152 of the deck 150 may be supported by and thermally coupled to the side rails 126, 127.
The side rails 126, 127 may also be formed from thermally conductive materials that are suitable for use in load bearing applications such as, without limitation, metals, polymers, carbon fiber, and/or combinations thereof. For example, the side rails 126, 127 may be formed from a metal or metal alloy having a relatively high thermal conductivity (e.g., greater than about 40 W/m*K), such as, but not limited to aluminum alloys, steel, titanium alloys, copper-containing alloys, other metal or metal alloy, or combinations thereof. In some embodiments, the side rails 126, 127 may be in the form of metal channels. Alternatively, in embodiments, the side rails 126, 127 may be formed from a polymer material having a relatively high thermal conductivity (e.g., greater than about 40 W/m*K) such as, without limitation, ultra-high molecular weight polyethylene, polypropylene, liquid crystalline polymer, polyphthalamide, polycarbonate, or the like. In these embodiments, the side rails 126, 127 may be in the form of polymer channels. As yet another alternative, in some embodiments, the side rails 126, 127 may be formed of carbon fiber or carbon fiber composites having a relatively high thermal conductivity (e.g., greater than about 40 W/m*K). In these embodiments, the side rails 126, 127 may be in the form of carbon fiber channels. The side rails 126, 127 may be formed from carbon fiber composites when radiolucency is desired.
Alternatively, in other embodiments, the side rails 126, 127 may be formed from a material suitable for load bearing applications having thermally conductive elements incorporated therein. The thermally conductive elements may be particles, fibers, strips, nanotubes, or other structures. The thermally conductive elements may have a relatively high thermal conductivity (e.g., greater than about 40 W/m*K). The thermally conductive elements may include for example and without limitation, the following: metal particles or metal fibers formed from copper, alloys of copper, silver, alloys of silver, gold, alloys of gold, and the like; polymer fibers or strips, such as polymer fibers or strips formed from ultra-high molecular weight polyethylene, polypropylene, liquid crystalline polymer, polyphthalamide, polycarbonate, or the like; carbon nanotubes, fibers, filaments, particles, or the like; or combinations thereof.
Each of the side rails 126, 127 may be a U-shaped channel, square channel, rectangular channel, or other-shaped channel. In embodiments such as the embodiment depicted in
The person support system 101 includes one or a plurality of cooling features to provide focal cooling of portions of the deck 150 that support targeted areas (e.g., the scapular areas, the sacral areas, the buttocks, the heals, the head, and the like) of a subject positioned on the person support system 101. In some embodiments, focal cooling of portions of the deck 150 provide focal cooling to the regions 129 of the support pad 130 that are in contact with the targeted areas of a subject. In embodiments, the targeted area of the subject may be cooled to a temperature that is from about 3° F. (1.7° C.) to about 25° F. (13.9° C.) less than body temperature. Referring to
As shown in
The cooling sources 142 positioned along the side rails 126, 127 may be at a lower temperature than a deck top surface temperature T3, which is measured at the top surface 154 of the deck 150 at portions of the deck 150 corresponding to the regions 129 of the support pad 130 contacting the subject, such that an overall temperature gradient between the top surface 154 of the deck 150 and the cooling source 142 promotes active conduction of heat away from the top surface 154 of the deck 150, through the deck 150, through the side rails 126, 127, and to the cooling source 142. This temperature gradient in turn causes conduction of heat away from the regions 129 of the top surface 131 of the support pad or away from portions of other support structures contacting the subject.
Referring still to
The deck 150 is thermally coupled to the side rails 126, 127 through contact of the bottom surface 152 of the deck 150 with the upper surface 128 of the side rails 126, 127. The side rail upper surface temperature T2 of the upper surface 128 of the side rails 126, 127 may be less than the deck top surface temperature T3 measured at the top surface 154 of the deck 150 at portions of the deck 150 that support the subject 105. For example, T3 may be measured at the top surface 154 of the deck 150 directly vertically below (i.e., in the −Z direction of the coordinate axes of
In embodiments in which the support pad 130 is supported by and thermally coupled to the deck 150 through contact of a bottom surface 134 of the support pad 130 with the top surface 154 of the deck 150, the deck top surface temperature T3 may be less than a support pad top surface temperature T4 measured at the top surface 131 of the support pad 130 in the region 129 of the support pad 130 in contact with the subject 105. In the region 129 of the support pad 130 contacting the subject 105, the top surface 131 of the support pad 130 absorbs body heat from the subject. The temperature difference between the support pad top surface temperature T4 and the deck top surface temperature T3 creates a temperature gradient in the support pad 130 that causes conductive heat flow from the top surface 131 of the support pad 130, through the support pad 130, to the top surface 154 of the deck 150. Conduction of heat from the top surface 131 of the support pad 130, through the support pad 130, to the top surface 154 of the deck 150 reduces the support pad top surface temperature T4 in the regions 129 of the support pad 130 in contact with the subject supported by the person support system 101. Although
As shown by the arrows in
Heat conduction from the top surface 131 of the support pad 130, through the support pad 130, deck 150, and side rails 126, 127, to the cooling source 142 may reduce the heat stored in the support pad 130. The heat conduction from the top surface 131 of the support pad 130 to the cooling source 142 may reduce the support pad top surface temperature T4 to a temperature sufficient to maintain the skin temperature of the subject 105 at the point of contact of the subject 105 with the top surface 131 of the support pad 130 in a range of from 70° F. to 95° F., from 70° F. to 85° F., or about 75° F. The support pad top surface temperature T4 may be maintained in a range of from 65° F. to 85° F., from 65° F. to 75° F., or about 70° F. To maintain the support pad top surface temperature T4 at the desired temperature, the cooling source 142 may maintain the side rail internal surface temperature T1 in a range of from 35° F. to 65° F., or from 40° F. to 60° F., or about 50° F. The cooling source 142 may maintain the deck top surface temperature T3 in a range of from 45° F. to 75° F., from 50° F. to 70° F., or about 60° F. The temperatures T1, T2, T3, and T4 may vary depending upon external factors, such as the presence and type of an accessory 590 (
In embodiments in which the subject 105 is supported directly by the top surface 154 of the deck 150, the heat conduction from the top surface 154 of the deck 150 to the cooling source 142 may reduce the deck top surface temperature T3 to a temperature sufficient to maintain the skin temperature of the subject 105 at the point of contact of the subject 105 with the top surface 154 of the deck 150 in a range of from 70° F. to 95° F., from 70° F. to 85° F., or about 75° F. To maintain the deck top surface temperature T3 at the target temperature, the cooling source 142 may maintain the side rail internal surface temperature T1 in a range of from 55° F. to 85° F., from 60° F. to 75° F., from 65° F. to 70° F., or about 70° F. The temperatures T1, T2, and T3 may vary depending upon external factors, such as the presence and type of an accessory 590 (
Various embodiments of the cooling sources 142 will now be described in detail with specific reference to the figures. Referring now to
In the embodiment depicted in
While the feed fluid 204 and the output fluid 202 are described as air in the embodiment depicted in
In still other embodiments, the temperature of the feed fluid 204 may be increased to reduce convection of heat from the internal surfaces of the side rail 126 and, hence, reduce the extraction of heat from the deck 150. For example, in embodiments, the feed fluid 204 may be passed over or through a heater, such as an electrical resistance heater or the like, which increases the temperature of the feed fluid 204 and reduces the convection of heat from the internal surfaces 121 of the side rail 126.
In still other embodiments, the convection of heat from the internal surfaces 121 of the side rail 126 may be controlled by controlling the volume flow rate of output fluid 202 flowing through the interior channel 180 of the side rail 126. For example, when more heat extraction from the internal surfaces 121 of the side rail 126 is desired (i.e., when more cooling of the deck 150 is desired), the volume flow rate of output fluid 202 directed through the interior channel 180 of the side rail 126 may be increased, by, for example, increasing the rotational velocity of the blower 200. Conversely, when less heat extraction from the internal surfaces 121 of the side rail 126 is desired (i.e., when less cooling of the deck 150 is desired), the volume flow rate of the output fluid 202 directed through the interior channel 180 of the side rail 126 may be decreased, by, for example, decreasing the rotational velocity of the blower 200.
While
The heat transfer plate 210 may be physically coupled to the internal surface 121 of the side rail 126 so that heat can be transferred from the side rail 126 to the heat transfer plate 210 through conduction. In some embodiments, the heat transfer plate 210 may be physically coupled to the internal surface 121 of the side rail 126 using one or more fasteners such as screws, clips, rivets, hook-and-loop fasteners (e.g., Velcro® brand hook and loop fasteners), other fasteners, or combinations of fasteners. Alternatively, in other embodiments, the heat transfer plate 210 may be coupled to the internal surface 121 of the side rail 126 using a thermally conductive adhesive, thermally conductive grease, other thermally conductive material, or combinations thereof. In still other embodiments, the heat transfer plate 210 may be received in a bracket (not shown) coupled to the internal surface 121 of the side rail 126. In some embodiments, the heat transfer plate 210 may be formed integral with the side rail 126. The outer surfaces 214 of the fins 212 are thermally coupled to the output fluid 202 from the blower 200 through convective heat transfer.
The heat transfer plate 210 thermally couples the internal surface 121 of the side rail 126 to the output fluid 202 from the blower 200. In operation, the blower 200 draws in feed fluid 204 (e.g., air, schematically depicted by a block arrow) and outputs output fluid 202 to create a flow of fluid through the side rail 126. As the output fluid 202 flows through the side rail 126, the output fluid 202 flows between the fins 212 of the heat transfer plate. As the output fluid 202 passes between the fins 212 of the heat transfer plate, heat conducted from the top surface 154 of the deck 150, through the deck 150, through the side rail 126, and through the heat transfer plate to the outer surface 214 of the fins 212 is dissipated into the interior channel 180 of the side rail 126 by forced convection, thereby cooling at least a portion of the support pad 130.
While the feed fluid 204 has been described herein as being a gas directed through the interior channel 180 of the side rail 126, it should be understood that other embodiments are contemplated and possible. For example, in an alternative embodiment, the feed fluid 204 may be a liquid, such as water, liquid nitrogen, or a coolant, directed through the interior channel 180 of the side rail 126 with a pump rather than a blower.
Referring now to
As shown in
The thermoelectric cooler 220 may be physically coupled to the internal surface 121 of the side rail 126 with the cooling plate 222 thermally coupled to the internal surface 121 of the side rail 126 so that heat can be transferred from the side rail 126 to the cooling plate 222 of the thermoelectric cooler 220 through conduction. In some embodiments, the thermoelectric cooler 220 may be physically coupled to the internal surface 121 of the side rail 126 using one or more fasteners such as screws, clips, rivets, hook-and-loop fasteners (e.g., Velcro® brand hook and loop fasteners), other fasteners, or combinations of fasteners. Alternatively, in other embodiments, the thermoelectric cooler 220 may be coupled to the internal surface 121 of the side rail 126 using a thermally conductive adhesive, thermally conductive grease, other thermally conductive material, or combinations thereof. In still other embodiments, the thermoelectric cooler 220 may be received in a bracket (not shown) coupled to the internal surface 121 of the side rail 126.
Alternatively, the thermoelectric cooler 220 may be positioned external to the side rail 126. For example, in embodiments, the cooling plate 222 of the thermoelectric cooler 220 may be thermally coupled to an external surface 123 of the side rail 126. In some embodiments, the cooling plate 222 of the thermoelectric cooler 220 may be physically and thermally coupled directly to an external surface 123 of the side rail 126. In these embodiments, the cooling plate 222 of the thermoelectric cooler 220 may be physically coupled to the external surface 123 of the side rail 126 using fasteners, thermally conductive adhesive, thermally conductive grease, or other thermally conductive materials as discussed herein.
As shown in
In the embodiments depicted in
Further, while
Referring now to
The canister 240 may be thermally coupled to the side rail 126. In some embodiments, the canister 240 may be positioned in the side rail 126 such that an outer surface 246 of the canister 240 contacts an internal surface 121 of the side rail 126. In embodiments, the canister 240 may be physically coupled to the internal surface 121 of the side rail 126 such that heat is transferred from the side rail 126 to the canister 240 through conduction. In some embodiments, the canister 240 may be physically coupled to the internal surface 121 of the side rail 126 using one or more fasteners such as screws, clips, rivets, hook-and-loop fasteners (e.g., Velcro® brand hook and loop fasteners), other fasteners, or combinations of fasteners. Alternatively, in other embodiments, the canister 240 may be coupled to the internal surface 121 of the side rail 126 using a thermally conductive adhesive, thermally conductive grease, other thermally conductive material, or combinations thereof. In still other embodiments, the canister 240 may be received in a bracket (not shown) coupled to the internal surface 121 of the side rail 126.
While
In operation, heat conducted from the deck 150 is conducted through the deck 150 to the side rail 126, and through the side rail 126 to the outer surface 246 of the canister 240. From there, the heat is conducted through the wall 244 of the canister 240 and into the thermally absorptive material 242 contained within the canister 240. The heat is absorbed by the thermally absorptive material 242. The flow of heat from the top surface 154 of the deck, through the deck 150, side rail 126, and canister 240, to the thermally absorptive material 242 of the canister 240 results in cooling of at least a portion of the top surface 154 of the deck 150.
In embodiments, heat conduction from the top surface 154 of the deck 150 to the thermally absorptive material 242 may continue until the heat capacity of the thermally absorptive material 242 is reached and/or an equilibrium temperature is reached between the thermally absorptive material 242 and the top surface 154 of the deck 150, more specifically, between the thermally absorptive material 242 and the subject positioned on the person support system 101. When this occurs, and further cooling is desired, the canister 240 may be removed and replaced with a fresh canister of thermally absorptive material to continue the conduction of heat from the top surface 154 of the deck 150.
Referring now to
Referring to
The thermally conductive cross-members 250 may be physically coupled to the bottom surface 152 of the deck 150, external surfaces 123 of the first side rail 126 and second side rail 127, or both so that heat can be transferred from the deck 150 to the thermally conductive cross-members 250 and from the thermally conductive cross-members 250 to the side rails 126, 127 through conduction. In some embodiments, the thermally conductive cross-members 250 may be physically coupled to the bottom surface 152 of the deck 150, external surfaces 123 of the first side rail 126 and second side rail 127, or both using one or more fasteners such as screws, clips, rivets, hook-and-loop fasteners (e.g., Velcro® brand hook and loop fasteners), other fasteners, or combinations of fasteners. Alternatively, in other embodiments, the thermally conductive cross-members 250 may be coupled to the bottom surface 152 of the deck 150, external surfaces 123 of the first side rail 126 and second side rail 127, or both using a thermally conductive adhesive, a thermally conductive grease, other thermally conductive materials, or combinations thereof. In still other embodiments, the thermally conductive cross-members 250 may be received in one or more brackets (not shown) coupled to the bottom surface 152 of the deck 150, external surfaces 123 of the first side rail 126 and second side rail 127, or both.
The thermally conductive cross-members 250 may be made from a thermally conductive material, such as copper or copper alloys for example, such that the thermally conductive cross-members 250 conduct heat from the bottom surface 152 of the deck 150 outward (i.e., in the +/−Y direction of the coordinate axes of
Referring to
Referring to
Referring to
Referring to
While the feed fluid 304 and the output fluid 302 are described as air in the embodiment depicted in
In still other embodiments, the temperature of the feed fluid 304 may be increased to reduce convection of heat from the bottom surface 152 of the deck 150 and, hence, reduce the extraction of heat from the deck 150. For example, in embodiments, the feed fluid 304 may be passed over or through a heater, such as an electrical resistance heater or the like, which increases the temperature of the feed fluid 304 and reduces the convection of heat from the bottom surface 152 of the deck 150.
In still other embodiments, the convection of heat from the bottom surface 152 of the deck 150 may be controlled by controlling the volume flow rate of output fluid 302 flowing across the bottom surface 152 of the deck 150. For example, when more heat extraction from the bottom surface 152 of the deck 150 is desired (i.e., when more cooling of the deck 150 is desired), the volume flow rate of output fluid 302 directed along the bottom surface 152 of the deck 150 may be increased, by, for example, increasing the rotational velocity of the blower 300. Conversely, when less heat extraction from the bottom surface 152 of the deck 150 is desired (i.e., when less cooling of the deck 150 is desired), the volume flow rate of output fluid 302 directed along the bottom surface 152 of the deck 150 may be decreased by, for example, decreasing the rotational velocity of the blower 300.
While
The heat transfer plate 310 may be physically coupled to the bottom surface 152 of the deck 150, such as to the bottom exterior surface 153 of the deck 150, so that heat can be transferred from the bottom surface 152 of the deck 150 to the heat transfer plate 310 through conduction. In some embodiments, the heat transfer plate 310 may be physically coupled to the bottom surface 152 of the deck 150 using one or more fasteners such as screws, clips, rivets, hook-and-loop fasteners (e.g., Velcro® brand hook and loop fasteners), other fasteners, or combinations of fasteners. In other embodiments, the heat transfer plate 310 may be coupled to the bottom surface 152 of the deck 150 using a thermally conductive adhesive, thermally conductive grease, other thermally conductive material, or combinations thereof. In still other embodiments, the heat transfer plate 310 may be received in a bracket (not shown) coupled to the bottom surface 152 of the deck 150. In some embodiments, the heat transfer plate 310 may be formed integral with the bottom surface 152 of the deck 150. The outer surfaces 314 of the fins 312 are thermally coupled to the output fluid 302 from the blower 300 through convective heat transfer.
In some embodiments, the heat transfer plate 310 thermally couples the bottom surface 152 of the deck 150 to ambient air under the deck 150. In these embodiments, heat is transferred from the fins 312 of the heat transfer plate 310 to the ambient air through convection, radiation, or both convection and radiation. Alternatively, as illustrated in
Referring now to
The thermoelectric cooler 320 may be physically coupled to the bottom surface 152 of the deck 150, such as the bottom exterior surface 153 of the deck 150, with the cooling plate 322 thermally coupled to the bottom surface 152 of the deck 150 so that heat can be transferred from the bottom surface 152 of the deck 150 to the cooling plate 322 of the thermoelectric cooler 320 through conduction. In some embodiments, the thermoelectric cooler 320 may be physically coupled to the bottom surface 152 of the deck 150 using one or more fasteners such as screws, clips, rivets, hook-and-loop fasteners (e.g., Velcro® brand hook and loop fasteners), other fasteners, or combinations of fasteners. Alternatively, in other embodiments, the thermoelectric cooler 320 may be coupled to the bottom surface 152 of the deck 150 using a thermally conductive adhesive, thermally conductive grease, other thermally conductive material, or combinations thereof. In still other embodiments, the thermoelectric cooler 320 may be received in a bracket (not shown) coupled to the bottom surface 152 of the deck 150.
In operation, heat conducted from the top surface 154 of the deck 150 is conducted generally downward (i.e., the −Z direction of the axis of
In the embodiments depicted in
Referring now to
In operation of the enclosure 330, a cooling fluid 338 is introduced to the cooling fluid inlet 332. The cooling fluid 338 may be a cooling gas such as air for example. It should be understood that other fluids are contemplated for use as the cooling fluid 338. For example, in some embodiments the cooling fluid 338 may be an inert gas, such as nitrogen. Alternatively, the cooling fluid 338 may be a combination of gases, such as combinations of nitrogen, carbon dioxide, and/or other gases. In embodiments, the temperature of the cooling fluid 338 may be reduced by conditioning the cooling fluid 338 to increase convection of heat from the outer surfaces 314 of the fins 312 of the heat transfer plate 310, hence, increase the extraction of heat from the deck 150. In such embodiments, the temperature of the cooling fluid 338 may be conditioned by passing the cooling fluid 338 over or through dry ice such that the cooling fluid is a mixture of, for example, atmospheric air and CO2 or nitrogen and CO2. As another example, the cooling fluid 338 may be conditioned by injecting liquid nitrogen into the cooling fluid 338 such that the cooling fluid 338 is a mixture of, for example, atmospheric air and N2 vapor or nitrogen and N2 vapor. As still another example, the cooling fluid 338 may be passed through a heat exchanger (not shown) in which a phase change of a working fluid flowing through a cooling element draws heat out of the cooling fluid 338 flowing past the cooling element to reduce the temperature of the cooling fluid. In embodiments, the cooling fluid 338 may be a liquid capable of absorbing heat transfer from the fins 312 of the heat transfer plate 310 through convection. Examples of cooling fluids 338 include, but are not limited to, water, alcohols (e.g., methanol, ethanol, propanol, isopropanol, etc.), glycols (e.g., ethylene glycol, propylene glycol, etc.), other cooling fluids, and combinations of these. In some embodiments, the cooling fluid 338 is water. Alternatively, in other embodiments, the cooling fluid 338 comprises one or more alcohols. In still other embodiments, the cooling fluid 338 is a glycol.
The cooling fluid 338 passes through the chamber 336 where the cooling fluid 338 contacts the outer surfaces 314 of the fins 312 of the heat transfer plate 310. As the cooling fluid 338 contacts and flows past the outer surface 314 of the fins 312, heat transfers from the outer surfaces 314 of the fins to the cooling fluid 338 through convection. The cooling fluid 338 passes out of enclosure 330 from the cooling fluid outlet 334. The cooling fluid 338 may be discharged to the ambient environment, such as by discharging cooling air or other cooling gas to the ambient air or directing cooling water to a drain. Alternatively, the cooling fluid 338 may be returned to a heat exchanger (not shown) where the heat is transferred out of the cooling fluid 338.
Although
Referring now to
The thermally absorptive material 342 contained in the canister 340 may include, without limitation, phase change materials, oils having relatively high heat capacities, dry ice, water ice, liquid nitrogen, or the like. Suitable phase change materials include, without limitation, alkanes having a melting temperature greater than or equal to about 5° C. and less than or equal to about 35° C. Examples of suitable alkanes include, without limitation, tetradecane, pentadecane, hexadecane, heptadecane, octadecane, and nonadecane. Suitable high heat capacity oils include, without limitation, mineral oils, silicon oils, fluorocarbon oils, and the like.
The canister 340 may be thermally coupled to the deck 150. In some embodiments, the canister 340 may be positioned against the bottom surface 152 of the deck 150, such as to the bottom exterior surface 153 of the deck 150, such that an outer surface 346 of the canister 340 contacts the bottom surface 152 of the deck 150. The canister 340 may be physically coupled to the bottom surface 152 of the deck 150 so that heat can be transferred from the bottom surface 152 of the deck 150 to the canister 340 through conduction. In some embodiments, the canister 340 may be physically coupled to the deck 150 using one or more fasteners such as screws, clips, rivets, hook-and-loop fasteners (e.g., Velcro® brand hook and loop fasteners), other fasteners, or combinations of fasteners. Alternatively, in other embodiments, the canister 340 may be coupled to the bottom surface 152 of the deck 150 using a thermally conductive adhesive, thermally conductive grease, other thermally conductive material, or combinations thereof. In still other embodiments, the deck 150 may include brackets 348 coupled to the bottom surface 152 of the deck 150. The brackets 348 may be sized to receive the canister 340 and maintain the canister 340 in contact with and/or thermally coupled to the bottom surface 152 of the deck 150.
In operation, heat from the top surface 154 of the deck 150 is conducted generally vertically downward (i.e., the −Z direction of the coordinate axes of
In embodiments, heat conduction from the deck 150 to the thermally absorptive material 342 may continue until the heat capacity of the thermally absorptive material 342 is reached and/or an equilibrium temperature is reached between the thermally absorptive material 342 and the top surface 154 of the deck 150, more specifically, a subject supported by the person support system 101. When this occurs, and further cooling is desired, the canister 340 may be removed and replaced with a fresh canister of thermally absorptive material to continue the conduction of heat from the top surface 154 of the deck 150.
Referring now to
Referring now to
The control unit 500 may be, by way of example and not limitation, a computing device that includes a microcontroller 501 communicatively coupled to a display device 504. The microcontroller 501 may include a processor 508 that is communicatively coupled to a non-transitory memory 510 storing computer-readable and executable instructions, which, when executed by the processor, facilitate cooling of the deck 150 of the person support system 101. That is, in embodiments, when the computer-readable and executable instructions are executed by the processor 508, the control unit 500 regulates the temperature of at least a portion of the top surface 154 (
In embodiments, the control unit 500 may include a temperature sensor 502 communicatively coupled to the microcontroller 501. The temperature sensor 502 outputs a signal (i.e., a temperature signal) indicative of the temperature of an object on which it is positioned. In embodiments, the temperature sensor 502 may be communicatively coupled to the microcontroller 501 with wires or, alternatively, wirelessly, such as when the temperature sensor 502 includes an RF transmitter (or transceiver) for transmitting the temperature signal from the temperature sensor 502 and the microcontroller 501 includes an RF receiver (or transceiver) for receiving the temperature signal from the temperature sensor 502.
In embodiments, the temperature sensor 502 may be positioned on the top surface 154 of the deck 150 at a position directly vertically below (i.e., in the −Z direction of the coordinate axes in the figures) a targeted area (e.g., the head, sacral area, the scapular areas, buttocks, heels or the like) of a subject supported by the person support system 101. The temperature sensor 502 may be positioned to detect either the temperature of the skin of the subject or the deck top surface temperature T3 (
Still referring to
In embodiments, the RFID reader 512 may be communicatively coupled to the microcontroller 501 with wires or, alternatively, wirelessly, such as when the RFID reader 512 includes an RF transmitter (or transceiver) for transmitting the accessory identification signal and the microcontroller 501 includes an RF receiver (or transceiver) for receiving the accessory identification signal from the RFID reader 512.
In embodiments, the control unit 500 may further include an input device 506 communicatively coupled to the microcontroller 501. The input device 506 may be used to input data, operating parameters, and the like into the control unit 500. In embodiments, the input device 506 may be a conventional input device such as a keyboard, mouse, track pad, stylus or the like. In embodiments, the input device 506 may be communicatively coupled to the microcontroller 501 with wires or, alternatively, wirelessly, such as when the input device 506 includes an RF transmitter (or transceiver) for transmitting an input signal and the microcontroller 501 includes an RF receiver (or transceiver) for receiving the input signal from the input device. In embodiments, the input device 506 may be used to, for example, input target cooling temperatures into the control unit 500, input subject data into the control unit 500, control the operation of one or more cooling sources 142 operatively connected to the control unit 500, and the like.
Still referring to
In some embodiments, the microcontroller 501 of the control unit 500 may be communicatively coupled to a cooling source 142, such as the blower 200 (
For example, in embodiments, computer readable and executable instructions stored in the non-transitory memory cause the control unit to receive a temperature signal from the temperature sensor 502 indicative of a measured temperature of the skin of a subject at a specific area or, alternatively, the support pad top surface temperature T4 (
For example and without limitation, when the cooling source 142 is a blower 200 as depicted in
Similarly, when the cooling source 142 is a blower 300 as depicted in
Conversely, when the microcontroller 501 of the control unit 500 determines that the temperature of the subject (i.e., the temperature of a specific portion of the skin of a subject, the deck top surface temperature T3 (
Alternatively, when the cooling source 142 is the thermoelectric cooler 220 as depicted in
Conversely, when the microcontroller 501 of the control unit 500 determines that the temperature of the subject (i.e., the temperature of a specific portion of the skin of a subject, the deck top surface temperature T3 (
In some embodiments, temperature measured with the temperature sensor 502 may be used to determine if a subject is appropriately positioned on the person support system 101 to facilitate effective cooling of a specific area of the subject. For example, in one embodiment, the actual temperature measured with the temperature sensor being relatively high when the temperature sensor 502 is applied directly to the skin of the subject may indicate that the subject is not properly positioned on the person support system 101 relative to the positions of the cooling sources 142 (i.e., proper cooling is not taking place). Alternatively, the actual temperature measured with the temperature sensor 502 being at or above normal body temperature may indicate that insufficient cooling is occurring and that the cooling source 142 should be adjusted (when present) or the thermally absorptive materials 242, 342 (i.e., PCMs or the like) exchanged or replaced (i.e., the cooling capacity of the materials is diminished or insufficient).
In embodiments where the side rails 126, 127 and/or the deck 150 are thermally coupled to a passive cooling source such as the canister 240, 340 containing thermally absorptive material 242, 342 as depicted in
For example, the control unit 500 may take into account variables that may adversely impact cooling, such as the presence of accessories 590 (e.g., linens, garments, pillows, bolsters, incontinence pad, and the like) in use with the person support system 101 and/or subject which may have an insulating effect. Specifically, any accessories 590 which may be positioned between the skin of the subject and the surface of the support pad(s) may have an insulating effect which diminishes cooling. In this embodiment, the control unit 500 may take into account any accessories 590 being used in conjunction with the person support system 101 and/or the subject positioned on the person support system 101 together with a desired target temperature input in the control unit by a user and adjust either the target temperature and/or the recommended thermally absorptive materials to account for the insulating effects of any accessories 590 that are present.
For example, in embodiments where the side rails 126, 127 and/or the deck 150 are thermally coupled to a cooling source 142 such as a canister 240, 340 containing thermally absorptive material 242, 342 as depicted in
For example and without limitation, when the accessory 590 is an incontinence pad, the incontinence pad may provide thermal insulation to the skin of the subject thereby requiring additional cooling to reach the desired target temperature at the surface of the skin. Accordingly, a greater amount of heat withdrawal capacity may be necessary to reach the desired target temperature than if the incontinence pad were not present. In this example, the control unit utilizes the identity of the accessory 590 in conjunction with the target temperature to determine a recommended thermally absorptive material and/or a recommended time schedule for replacing the thermally absorptive material in order to achieve the desired target temperature.
As another example, in embodiments where the side rails 126, 127 and/or the deck 150 are thermally coupled to a cooling source 142, such as a blower 200, 300 (
For example and without limitation, when the target temperature is 75° F. and the accessory 590 is an incontinence pad, the incontinence pad may provide thermal insulation to the skin of the subject thereby requiring additional cooling to reach the desired target temperature at the surface of the skin. Accordingly, a greater amount of heat withdrawal capacity may be necessary to reach the desired target temperature at the surface of the skin than if the incontinence pad were not present. In this example, the control unit 500 utilizes the identity of the accessory 590 in conjunction with the desired target temperature to determine an adjusted target temperature at the surface of the accessory 590 (i.e., at the top surface 131 of the support pad 130) such that the desired target temperature is reached at the surface of the skin. The control unit 500 then operates the cooling source 142, in conjunction with the temperature signal from the temperature sensor 502, to achieve and maintain the adjusted target temperature at the surface of the accessory 590 (i.e., at the top surface 131 of the support pad 130) and, in turn, the desired target temperature at the surface of the subject's skin by controlled heat extraction from the top surface 154 of the deck 150, through the deck 150 and/or side rails 126, 127 to the cooling source 142.
In embodiments where the target temperature is adjusted to account for the presence of insulating accessories 590 and/or the type of thermally absorptive materials 242, 342 are selected to account for the presence of insulating accessories 590, the comfort of the patient may be improved by preventing over-cooling. Moreover, the workflow of a user (i.e., a caregiver) may be improved by minimizing the amount of cooling delivered to achieve a specific temperature, thereby decreasing the frequency of user intervention to monitor temperature and/or replace exhausted thermally absorptive materials. Further, by tailoring the operation of the cooling source to deliver only the minimal amount of cooling needed to obtain the desired target temperature may reduce the amount of energy expended on cooling.
Still referring to
Referring to
Referring to
Based on the foregoing, it should be understood that the non-transitory memory 510 includes computer readable and executable instructions which, when executed by the processor 508, cause the microcontroller 501 to receive input signals from the temperature sensor 502, RFID reader 512, input device 506, and/or display device 504 and output signals to at least the display device 504 based on the input signals received. In some embodiments, the microcontroller 501 also outputs control signals to a cooling source 142 such as a blower 200, 300 or a thermoelectric cooler 220, 320 to regulate cooling of a support pad 130.
In embodiments described herein, the focal cooling of at least a portion of the top surface 154 of the deck 150 is achieved by conducting heat from the top surface 154 of the deck 150 and dissipating that heat with a heat sink, either by conduction, convection, radiation, or combinations thereof. The heat conducted away from the deck 150 is, effectively, waste heat. In some embodiments of the person support systems 101 described herein, the heat conducted away from the deck 150 may be recycled and repurposed. For example, the heat conducted away from the deck 150 may be recycled to warm the subject positioned on the person support system 101.
Referring to
Referring now to
In embodiments, the warming fluid 610 directed through the flexible conduit 604 and the frame conduit 622 may be, for example, a gas such as, without limitation, air or nitrogen. Alternatively, the warming fluid 610 directed through the flexible conduit 604 and the frame conduit 622 may be, for example, a liquid such as, without limitation, water, mineral oil, or the like.
In operation, the thermoelectric cooler 220 conducts heat from the deck 150 as described hereinabove with respect to
While a closed loop embodiment of the warming blanket has been described, it should be understood that an open loop embodiment is contemplated and possible. Referring again to
In operation, the thermoelectric cooler 220 conducts heat from the top surface 154 of the deck 150 as described hereinabove with respect to
Still referring to
In operation, the thermoelectric cooler 220 conducts heat from the top surface 154 of the deck 150 as described hereinabove with respect to
Still referring to
In operation, the thermoelectric cooler 220 conducts heat from the top surface 154 of the deck 150 as described hereinabove with respect to
Referring to
While specific reference has been made herein to use of the cooling features 140 in conjunction with person support systems 101 such as surgical tables and/or spine tables, it should be understood that use of the cooling features 140 with other types of person support systems 101 are contemplated and possible. For example, some embodiments of the cooling features 140, such as the embodiments depicted in
While various embodiments of cooling features have been shown and described herein in conjunction with person support systems, it should be understood that other applications are contemplated and possible. For example, the cooling features described herein may be used in conjunction with other medical equipment including, without limitation, wheelchairs, stretchers, procedural stretchers, gurneys, cots, hospital beds, and the like or any other medical equipment which utilizes a deck or other support surface on which a subject may be positioned for extended periods of time.
Various embodiments described herein include cooling features in the form of cooling sources thermally coupled to the deck and/or the side rail of a person support system. The cooling features may reduce a temperature of the tissue in contact with the person support system, which may further reduce the likelihood of the subject developing pressure injuries. In various embodiments, the deck, support pad, and/or side rails are made of radiolucent materials to enable the deck, support pad, and/or side rails to be used without interfering with imaging techniques utilized in conjunction with the person support systems on which the support pads are positioned.
Referring now to
The person support system 900 further includes a cooling system 920 to provide focal cooling to an area of a top surface 906 of the support pad 905 that is in contact with a subject supported by the support pad 905. For example, the cooling system 920 may provide focal cooling to an area of the top surface 906 of the support pad 905 in contact with the sacral or buttocks areas of the subject. Contact of the subject with the top surface 906 of the support pad 905 causes heat to accumulate in the support pad 905. The focal cooling provided by the cooling system 920 removes heat accumulated in the support pad 905 and reduces a temperature of the top surface 906 of the support pad 905. Reducing the temperature of the top surface 906 may reduce the skin temperature of the subject, which may reduce the formation of pressure injuries in areas of the subject supported by the support pad 905. In some embodiments, the cooling system 920 may transfer the heat from the support pad 905 to the back side of the person support system 900 where the heat may be dissipated without requiring external power.
As shown in
In embodiments, the reservoir 922 may be positioned in the support pad 905 of the person support system 900. Referring to
Referring back to
The heat exchanger 924 includes a heat exchanger inlet 934 in fluid communication with the first fluid conduit 926 and a heat exchanger outlet 936 in fluid communication with the second fluid conduit 928. The heat exchanger 924 removes heat from the cooling fluid entering the heat exchanger 924. The heat removed by the heat exchanger 924 is then transferred to the ambient air or other heat sink through radiation and/or convection. In some embodiments, the heat exchanger 924 may include a plurality of cooling fins 940. The cooling fins 940 provide increased surface area for transferring heat from the cooling fluid to the ambient air through radiation and/or natural convection. The cooling fins 940 may be made from a thermally conductive material, such as copper or copper alloys for example, such that the cooling fins 940 conduct heat from the cooling fluid to the outer surfaces of the cooling fins 940, where the heat may be transferred to the ambient air or other heat sink through radiation and/or convection. The cooling fins 940 may include other thermally conductive materials, such as the thermally conductive metals, polymers, and/or carbon fibers.
In some embodiments, the heat exchanger 924 may remove heat from the cooling fluid by conduction and then may transfer the heat to the ambient air or other heat sink through natural convection. Alternatively, in other embodiments, the heat exchanger 924 may additionally include a cooling source 942 for removing heat from the cooling fluid and absorbing and/or dissipating the heat to a heat sink, such as the ambient air. The cooling source 942 may include a thermoelectric cooler, a blower or fan, a thermally absorptive material, other cooling source, or combinations of cooling sources 942 as previously describe herein.
As previously discussed, the first fluid conduit 926 extends from the reservoir outlet 932 to the heat exchanger inlet 934, and the second fluid conduit 928 extends from the heat exchanger outlet 936 to the reservoir inlet 930. In some embodiments, the first fluid conduit 926 and/or the second fluid conduit 928 may be disposed within the frame 902 of the person support system 900. In some embodiments, the first fluid conduit 926 and the second fluid conduit 928 may be rigid fluid conduits. In some embodiments, the first fluid conduit 926 and/or the second fluid conduit 928 may be a metal conduit, such as a copper or steel conduit for example. In some embodiments, the first fluid conduit 926 and/or the second fluid conduit 928 may have a mesh disposed within the copper conduit. The mesh may provide additional surface area within the first or second conduits 926, 928 to promote phase change of the cooling fluid. Alternatively, the first fluid conduit 926 and/or the second fluid conduit 928 may be flexible conduits. In some embodiments, the first fluid conduit 926 and/or the second fluid conduit 928 may be made from a woven metal, flexible polymer, rubber, other flexible material, or combinations of these.
In embodiments, the cooling fluid may be a fluid capable of absorbing heat from the support pad 905. Examples of cooling fluids include, but are not limited to, water, alcohols (e.g., methanol, ethanol, propanol, isopropanol, etc.), glycols (e.g., ethylene glycol, propylene glycol, etc.), other cooling fluids, and combinations of these. In some embodiments, the cooling fluid is water. In some embodiments, the cooling fluid comprises one or more alcohols. In still other embodiments, the cooling fluid is a glycol. In some embodiments, the cooling fluid may be a fluid that undergoes a phase change from liquid to gas at a temperature of from 50° F. to 95° F., or from 50° F. to 80° F.
The reservoir 922, heat exchanger 924, first fluid conduit 926, and second fluid conduit 928 form a cooling circuit 944. In operation, heat from the subject transfers to the support pad 905 through contact of the support pad 905 with the subject supported by the person support system 900. Heat from the support pad 905 is then transferred to the cooling fluid in the reservoir 922 through conduction and/or convection. With the heat exchanger 924 elevated vertically relative to the reservoir 922, the heated cooling fluid exhibits a natural buoyancy, which causes the heated cooling fluid to travel in a generally vertically upward direction (i.e., +Z direction of the coordinate axes of
The cooling system 920 described herein provides focal cooling to a portion of the person support system 900 for preventing pressure injuries in a subject supported by the person support system 900. The cooling system 920 is passive such that it may not interfere with current subject transport procedures for transporting the subject using the person support system 900. In some embodiments, the cooling system 920 may not require power or access to other support systems or utilities, which may not be available on certain person support systems 900 such as stretchers, cots, or other support systems. In embodiments, the cooling system 920 may be lightweight such that the cooling system 920 does not significantly affect the weight of the stretcher, and thus impact the mobility of the person support system 900.
In some embodiments, the cooling system 920 may further include a pump (not shown) for moving the cooling fluid through the cooling circuit 944. Additionally, in some embodiments, the person support system 900 may include a control unit, such as the control unit 500 previously discussed in relation to
Referring to
In operation, cooled cooling fluid from the heat exchanger 924 passes through the second fluid conduit 928 to the inlet 952 of the heat transfer conduit 950, the cooled cooling fluid then travels through the heat transfer conduit 950. Heat from the support pad 905 transfers through the heat transfer conduit 950 to the cooling fluid to produce a heated cooling fluid. The heated cooling fluid has a greater temperature than the cooled cooling fluid entering the heat transfer conduit 950. The heated cooling fluid exits the heat transfer conduit 950 from the outlet 954 of the heat transfer conduit 950.
The heated cooling fluid exhibits a natural buoyancy, which causes the heated cooling fluid to travel in the generally vertically upward direction (i.e., +Z direction of the coordinate axes of
Referring now to
The thermally conductive elements 960 are thermally coupled to the support pad 905 in areas of the support pad 905 contacting an area of the subject, such as the buttocks or sacral area of the subject, such that heat from the support pad 905 is transferred to the thermally conductive elements 960. In some embodiments, the thermally conductive elements 960 may be thermally coupled to the top surface 906 of the support pad 905. Alternatively, the thermally conductive elements 960 may be thermally coupled to an upper portion, middle portion, or lower portion of the support pad 905. The thermally conductive elements 960 extend from the support pad 905 to the heat exchanger 924. In some embodiments, the thermally conductive elements 960 may be disposed within the frame 902 of the person support system 900. Alternatively, the thermally conductive elements 960 may be disposed along an underside of the support pad 905.
The heat exchanger 924 provides cooling to an end of the thermally conductive elements 960 opposite the support pad 905. By cooling the end of the thermally conductive elements 960, the heat exchanger 924 reduces the temperature of the end of the thermally conductive elements 960. This reduced temperature is less than a temperature of support pad 905. The difference in temperature between the end of the thermally conductive elements 960 coupled to the heat exchanger 924 and the ends coupled to the support pad 905 creates a temperature gradient in the thermally conductive elements 960. The temperature gradient in the thermally conductive elements 960 cause heat to be conducted from the support pad 905 along the thermally conductive elements 960 to the heat exchanger 924. The heat exchanger 924 may include cooling fins 940. In embodiments, the heat exchanger 924 may include any of the cooling sources previously discussed herein, including, but not limited to, a blower and/or fan, thermoelectric cooler, thermally absorptive material, other cooling source, or combinations thereof.
The thermally conductive elements 960 conduct heat from the support pad 905 to the heat exchanger 924, where the heat is then absorbed or dissipated into the ambient air or other heat sink. In operation, heat from the subject supported by the support pad 905 is transferred to the support pad 905 through contact of the subject with the support pad 905. Heat from the support pad 905 is then transferred to the thermally conductive elements 960 thermally coupled to the support pad 905. The thermally conductive elements 960 conduct the heat from the support pad 905 to the heat exchanger 924 driven by the temperature gradient between the support pad 905 and the heat exchanger 924. The heat exchanger 924 then absorbs the heat and/or dissipates the heat to the ambient air and/or other heat sink.
Referring now to
The thermally conductive elements 960 may be thermally coupled to the thermally absorptive material 972 in the pad 970 to remove heat absorbed by the thermally absorptive material 972. The thermally conductive elements 960 may be thermally coupled to the thermally absorptive material 972 through one or more couplers, such as the couplers disclosed in co-pending U.S. patent application Ser. No. 15/348,080, filed Nov. 10, 2016, incorporated by reference herein in its entirety.
In operation, heat from the subject supported by the pad 970 is transferred through the pad cover 974 of the pad 970 to the thermally absorptive material 972. The thermally absorptive material 972 absorbs the heat from the subject. Some of the heat absorbed by the thermally absorptive material 972 is then transferred to the thermally conductive elements 960. The thermally conductive elements 960 conduct the heat from the thermally absorptive material 972 to the heat exchanger 924, where the heat is absorbed and/or dissipated to the ambient air or another heat sink. Removal of heat from the thermally absorptive material 972 may prolong the effectiveness of the thermally absorptive material 972 by removing some of the heat absorbed by the thermally absorptive material 972, thereby restoring the capacity of the thermally absorptive material 972 to absorb more heat from the subject.
The cooling systems 920 described relative to
The harness 980 may be used to couple the heat exchanger 924 to the person support system 900. The reservoir 922, heat transfer conduit 950, thermally conductive elements 960, pad 970, or combinations of these may be positioned to provide cooling to the person support system 900. In some embodiments, the reservoir 922, heat transfer conduit 950, thermally conductive elements 960, or pad 970 may be positioned on top of (i.e., in the +Z direction of the coordinate axes in the figures) the support pad 905 or other support surface (e.g., mattress, seat, or other surface) to provide cooling directly to the subject supported by the person support system 900. In these embodiments, the reservoir 922, heat transfer conduit 950, thermally conductive elements 960, or pad 970 may be positioned between the support pad 905 or other support surface and the subject supported thereon. Alternatively, in other embodiments, the reservoir 922, heat transfer conduit 950, thermally conductive elements 960, or pad 970 may be positioned underneath the support pad 905 or other support surface (i.e., below the support pad 905 or other support surface in the −Z direction of the coordinate axes of the figures) such that heat is conducted from the subject, through the support pad or other support surface, to the reservoir 922, heat transfer conduit 950, thermally conductive elements 960, or pad 970. The reservoir 922, heat transfer conduit 950, thermally conductive elements 960, or pad 970 may also be insertable into a recess in the support pad 905 or other support surface as shown in
A first aspect of the present disclosure may be directed to a person support system comprising a longitudinal frame comprising at least one side rail and a deck positioned on the longitudinal frame, the deck comprising a thermally conductive material. The person support system may further comprise a cooling source thermally coupled to the deck, wherein the cooling source draws heat from at least a portion of a top surface of the deck and through the deck thereby cooling the at least a portion of the top surface of the deck.
A second aspect of the present disclosure may include the first aspect, wherein the cooling source is physically and thermally coupled to the at least one side rail, the deck is thermally coupled to the at least one side rail, and the cooling source draws heat from the at least a portion of the upper surface of the deck, through the deck, and through the at least one side rail thereby cooling the at least a portion of the top surface of the deck.
A third aspect of the present disclosure may include either the first or the second aspects, further comprising at least one thermally conductive cross-member thermally coupled to a lower surface of the deck and to a surface of the at least one side rail, wherein the cooling source draws heat from the at least a portion of the top surface of the deck, through the deck, through the at least one thermally conductive cross-member, and through the at least one side rail thereby cooling the at least a portion of the top surface of the deck.
A fourth aspect of the present disclosure may include the first aspect, wherein the cooling source is thermally and physically coupled directly to a bottom surface of the deck, wherein the cooling source draws heat from the at least a portion of the top surface of the deck and through the deck thereby cooling the at least a portion of the top surface of the deck.
A fifth aspect of the present disclosure may include the fourth aspect, wherein the cooling source is thermally coupled to the bottom surface of the deck by a thermally conductive grease or a thermally conductive adhesive.
A sixth aspect of the present disclosure may include either of the fourth or fifth aspects, further comprising a bracket coupled to the bottom surface of the deck, the bracket shaped to maintain the cooling source thermally coupled to the bottom surface of the deck.
A seventh aspect of the present disclosure may include any of the first through sixth aspects, wherein the cooling source comprises a fan oriented to direct an output fluid through the at least one side rail or across a bottom surface of the deck.
An eighth aspect of the present disclosure may include the seventh aspect, wherein the cooling source comprises a heat transfer plate thermally coupled to an internal surface of the at least one side rail or the bottom surface of the deck, the heat transfer plate having a plurality of fins extending therefrom, wherein the fan is oriented to direct the output fluid across the plurality of fins of the heat transfer plate.
A ninth aspect of the present disclosure may include any of the first through sixth aspects, wherein the cooling source comprises a thermoelectric cooler having a cooling plate thermally coupled to a surface of the deck or a surface of the at least one side rail.
A tenth aspect of the present disclosure may include the ninth aspect, wherein a heating plate of the thermoelectric cooler comprises a plurality of cooling fins extending therefrom.
An eleventh aspect of the present disclosure may include either of the ninth or tenth aspects, wherein the cooling source comprises a fan positioned to direct an output fluid across a heating plate of the thermoelectric cooler.
A twelfth aspect of the present disclosure may include the ninth aspect, wherein a heating plate of the thermoelectric cooler comprises a plurality of cooling fins extending therefrom and the cooling source comprises a fan positioned to direct an output fluid across the heating plate of the thermoelectric cooler.
A thirteenth aspect of the present disclosure may include the first or fourth aspects, wherein the cooling source comprises a heat transfer plate thermally coupled to the bottom surface of the deck, the heat transfer plate having a plurality of fins, and an enclosure having a cooling fluid input and a cooling fluid output, the enclosure coupled to the bottom surface of the deck or the heat transfer plate to form a chamber. When a cooling fluid is passed through the chamber from the cooling fluid inlet of the enclosure to the cooling fluid outlet, the cooling fluid contacts the fins of the heat transfer plate thereby transferring heat from the fins to the cooling fluid.
A fourteenth aspect of the present disclosure may include the first or the fourth aspects, wherein the cooling source comprises a thermoelectric cooler having a cooling plate thermally coupled to the bottom surface of the deck and a heating plate, and an enclosure having a cooling fluid input and a cooling fluid output, the enclosure coupled to the bottom surface of the deck or the thermoelectric cooler to form a chamber. When a cooling fluid is passed through the chamber from the cooling fluid inlet of the enclosure to the cooling fluid outlet, the cooling fluid contacts the heating plate of the thermoelectric cooler thereby transferring heat from the heating plate to the cooling fluid.
A fifteenth aspect of the present disclosure may include any of the first through sixth aspects, wherein the cooling source comprises a thermally absorptive material thermally coupled to a bottom surface of the deck or an internal surface of the at least one side rail.
A sixteenth aspect of the present disclosure may include the fifteenth aspect, wherein the thermally absorptive material is contained within a canister thermally coupled to the bottom surface of the deck or an internal surface of the at least one side rail.
A seventeenth aspect of the present disclosure may include the fifteenth or sixteenth aspects, wherein the thermally absorptive material is a phase change material.
An eighteenth aspect of the present disclosure may include any of the first through seventeenth aspects, wherein the person support system is one of an surgical table, a spine table, a hospital bed, a procedural stretcher, a stretcher, a gurney, a cot or a wheelchair.
A nineteenth aspect of the present disclosure may include any of the first through eighteenth aspects, further comprising a control unit communicatively coupled to a temperature sensor, the control unit comprising a processor and a non-transitory memory storing computer readable and executable instructions which, when executed by the processor, cause the control unit to: receive a temperature signal from the temperature sensor indicative of a measured temperature of skin of a subject, the top surface of the deck, or a top surface of a support pad supported by the deck; compare the measured temperature to a target temperature; and adjust an operating parameter of the cooling source when the measured temperature is not equal to the target temperature, thereby increasing or decreasing cooling of the deck until the measured temperature is equal to the target temperature.
A twentieth aspect of the present disclosure may include any of the first through eighteenth aspects, further comprising a control unit communicatively coupled to an input device and a temperature sensor, the control unit comprising a processor and a non-transitory memory storing computer readable and executable instructions which, when executed by the processor, cause the control unit to: receive an input indicative of a target temperature; receive an input indicative of an identity of an accessory; determine an adjusted target temperature based on the target temperature and the identity of the accessory; receive a temperature signal from the temperature sensor indicative of a measured temperature of skin of a subject, of the top surface of the deck, or of a surface of a support pad supported by the deck; and adjust an operating parameter of the cooling source thereby increasing or decreasing cooling of the deck until the measured temperature is equal to the adjusted target temperature.
A twenty-first aspect of the present disclosure may include the twentieth aspect, further comprising an RFID reader communicatively coupled to the control unit, wherein the computer readable and executable instructions, when executed by the processor, further cause the control unit to receive an accessory identification signal from the RFID reader indicative of the identity of the accessory, wherein the accessory identification signal is the input indicative of the identity of the accessory.
A twenty-second aspect of the present disclosure may include the first through sixth aspects, wherein the cooling source comprises thermally absorptive material and the person support system further comprises a control unit communicatively coupled to an input device, the control unit comprising a processor and a non-transitory memory storing computer readable and executable instructions which, when executed by the processor, cause the control unit to: receive an input indicative of a target temperature; receive an input indicative of an identity of an accessory; and determine a recommended thermally absorptive material based on the target temperature and the identity of the accessory.
A twenty-third aspect of the present disclosure may include the twenty-second aspect, further comprising an RFID reader communicatively coupled to the control unit, wherein the computer readable and executable instructions, when executed by the processor, further cause the control unit to receive an accessory identification signal from the RFID reader indicative of the identity of the accessory, wherein the accessory identification signal is the input indicative of the identity of the accessory.
A twenty-fourth aspect of the present disclosure may include either of the twenty-second or twenty-third aspects, wherein the computer readable and executable instructions, when executed by the processor, further cause the control unit to determine a recommended time schedule for replacing the thermally absorptive material to achieve the target temperature.
A twenty-fifth aspect of the present disclosure may be directed to a cooling system for a person support system, the cooling system comprising a reservoir or a heat transfer conduit thermally coupleable to a deck or a support pad of the person support system, a heat exchanger, a first fluid conduit in fluid communication with a heat exchanger inlet and a reservoir outlet or an outlet of the heat transfer conduit, and a second fluid conduit in fluid communication with a heat exchanger outlet and a reservoir inlet or an inlet of the heat transfer conduit. The reservoir or heat transfer conduit, the heat exchanger, the first fluid conduit, and the second fluid conduit form a cooling circuit such that when a cooling fluid is disposed in the cooling circuit and the heat exchanger is positioned vertically higher than the reservoir of the heat transfer conduit, the cooling fluid absorbs heat from the deck or the support pad of the person support system, flows through the first fluid conduit to the heat exchanger, releases heat in the heat exchanger, and flows through the second fluid conduit back to the reservoir or the heat transfer conduit.
A twenty-sixth aspect of the present disclosure may include the twenty-fifth aspect, further comprising a cooling fluid disposed in the cooling circuit. A twenty-seventh aspect of the present disclosure may include the twenty-sixth aspect, wherein the cooling fluid comprises one or more of water, alcohol, or glycol. A twenty-eighth aspect of the present disclosure may include either of the twenty-sixth or twenty-seventh aspects, wherein flow of the cooling fluid through the cooling circuit proceeds through buoyancy forces. A twenty-ninth aspect of the present disclosure may include any of the twenty-fifth through twenty-eighth aspects, further comprising a pump fluidly coupled to the cooling circuit, wherein the pump circulates a cooling fluid through the cooling circuit. A thirtieth aspect of the present disclosure may include any of the twenty-fifth through twenty ninth aspects, wherein the heat exchanger comprises a cooling source. A thirty-first aspect of the present disclosure may include the thirtieth aspect, wherein the cooling source includes one or more of a blower, a heat transfer plate, a thermoelectric cooler, or a thermally absorptive material.
A thirty-second aspect of the present disclosure may include the twenty-fifth through thirty-first aspects, wherein the cooling system is removable from the person support system. A thirty-third aspect of the present disclosure may include the twenty-fifth through thirty-second aspects, wherein the heat exchanger includes a harness for removeably coupling the heat exchanger to a portion of the person support system.
A thirty-fourth aspect of the present disclosure may include the twenty-fifth through thirty-third aspects, wherein the cooling system comprises the reservoir. A thirty-fifth aspect of the present disclosure may include the twenty-fifth through thirty-fourth aspects, wherein the cooling system comprises the heat transfer conduit.
It will be apparent to those skilled in the art that various modifications and variations can be made to the embodiments described herein without departing from the spirit and scope of the claimed subject matter. Thus it is intended that the specification cover the modifications and variations of the various embodiments described herein provided such modification and variations come within the scope of the appended claims and their equivalents.
This application claims the benefit of U.S. Provisional Application Ser. No. 62/452,697 filed Jan. 31, 2017, which is incorporated by reference herein in its entirety.
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