WO2024126706A1

WO2024126706A1 - Passive device for delivering a predefined coolant to a heat exchanger

Info

Publication number: WO2024126706A1
Application number: PCT/EP2023/085866
Authority: WO
Inventors: Rudolf Kober; Andreas KORELL; Ralf Bernd ENGELHARDT; Andreas Johann FRITSCHI
Original assignee: MAQUET CARDIOPULMONARY GmbH
Priority date: 2022-12-15
Filing date: 2023-12-14
Publication date: 2024-06-20

Abstract

An intermediate circuit device for heat transfer for an extracorporeal circulation system includes a first fluid flow path for carrying a first fluid, a second fluid flow path for carrying a second fluid, an intermediate heat exchanger including at least a portion of the first fluid flow path and at least a portion of the second fluid flow path, and a fluid conveyor associated with the first fluid flow path and the second fluid flow path. The fluid conveyor is configured to convert fluid flow in the first fluid path into mechanical energy to drive fluid flow in the second fluid flow path. The intermediate heat exchanger is configured to facilitate heat transfer between the first fluid flowing through the first fluid flow path and the second fluid flowing through the second fluid flow path.

Description

PASSIVE DEVICE FOR DELIVERING A PREDEFINED COOLANT TO A HEAT

EXCHANGER

BACKGROUND OF THE DISCLOSURE

Field of the Disclosure

[0001] The present disclosure relates to extracorporeal blood flow systems and, more particularly to an intermediate coolant circuit device thereof.

Description of Related Art

[0002] The field of extracorporeal circulation includes various techniques of providing cardiac and respiratory function to an individual whose own heart and lungs are unable to sustain life. A patient is connected to an extracorporeal circulation system including a blood pump and a membrane lung (previously known as an oxygenator) to provide blood perfusion and gas exchange. The extracorporeal circulation system may further include one or more heat exchangers to raise and/or lower the blood temperature to set or maintain a desired body temperature. Such heat exchangers typically utilize a blood circuit and a separate coolant circuit to facilitate indirect heat transfer between the blood and the coolant. The blood and coolant circuits are ideally completely isolated from one another to prohibit coolant from mixing with the patient’s blood. While the coolant itself may be biocompatible (for example, water), disinfectants added to the coolant (for example, chlorine or hydrogen peroxide) can have adverse effects on the patient if inadvertent contact with the blood occurs.

[0003] As such, the coolant within the heat exchanger must be prohibited from entering the blood circuit to prevent harm to the patient. However, contamination of the blood with the coolant can occur under various circumstances. First, structural leakage within the heat exchanger can allow coolant to enter the blood circuit. Second, disinfectant compounds within the coolant may permeate the internal structure of the heat exchanger and enter the blood circuit. Third, coolant may spill on the connecting ports of the heat exchanger during assembly/disassembly of the system, and subsequently work its way into the blood circuit.

[0004] In view of the above, there exists a need in the art to improve isolation of the blood circuit and coolant circuit of extracorporeal circulation systems in order to prevent potentially harmful compounds from entering the patient’s blood stream. SUMMARY OF THE DISCLOSURE

[0005] In view of the foregoing, the present disclosure is directed to devices, systems, and methods for warming and/or cooling a patient during an extra corporeal circulation procedure. Embodiments of the present disclosure are directed to an intermediate circuit device for heat transfer for an extracorporeal circulation system. In some embodiments, the device includes a first fluid flow path for carrying a first fluid, a second fluid flow path for carrying a second fluid, an intermediate heat exchanger including at least a portion of the first fluid flow path and at least a portion of the second fluid flow path, and a fluid conveyor associated with the first fluid flow path and the second fluid flow path. The fluid conveyor is configured to convert fluid flow in the first fluid path into mechanical energy to drive fluid flow in the second fluid flow path. The intermediate heat exchanger is configured to facilitate heat transfer between the first fluid flowing through the first fluid flow path and the second fluid flowing through the second fluid flow path.

[0006] In some embodiments, the fluid conveyor includes a turbine positioned in the first fluid flow path and configured to generate mechanical energy in response to fluid flow through the first fluid path, and a pump coupled to the turbine and driven by the mechanical energy generated by the turbine, wherein the pump is configured to drive the second fluid through the second fluid flow path.

[0007] In some embodiments, the pump is powered entirely by the turbine.

[0008] In some embodiments, the turbine is mechanically coupled to the pump.

[0009] In some embodiments, the mechanical coupling includes a gear box, a belt, or combinations thereof.

[0010] In some embodiments, the turbine is magnetically coupled to the pump.

[0011] In some embodiments, the pump includes a rotary displacement pump.

[0012] In some embodiments, the pump includes a centrifugal pump.

[0013] In some embodiments, the fluid conveyor includes a membrane pump. The membrane pump includes a membrane associated with the first fluid flow path and the second fluid flow path, the membrane configured to change state in response to fluid flow through the first fluid flow path. The change in state of the membrane drives the second fluid through the second fluid flow path.

[0014] In some embodiments, the membrane pump further includes at least one valve in the second fluid flow path, the at least one valve configured to open and close in response to the change in state of the membrane. [0015] In some embodiments, the membrane pump further includes one or more compliance elements configured to absorb abrupt pressure changes in the first fluid flow path.

[0016] In some embodiments, the second fluid flow path is pre-filled with the second fluid.

[0017] In some embodiments, the second fluid is sterile.

[0018] In some embodiments, the second fluid is water-based.

[0019] In some embodiments, the second fluid is a coolant.

[0020] In some embodiments, the intermediate circuit device further includes a housing containing the intermediate heat exchanger.

[0021] In some embodiments, the housing contains the fluid conveyor.

[0022] In some embodiments, the first fluid flow path is fully isolated from the second fluid flow path.

[0023] In some embodiments, the second fluid flow path includes an inlet port having a sterile connector configured for connection to a patient heat exchanger, and an outlet port having a sterile connector configured for connection to the patient heat exchanger.

[0024] Other embodiments of the present disclosure are directed to an extracorporeal circulation system. The system includes a heater cooler unit, a patient heat exchanger, and an intermediate circuit device for heat transfer. The intermediate circuit device includes a first fluid flow path fluidly connected to the heater cooler unit and carrying a first fluid, a second fluid flow path fluidly connected to the patient heat exchanger and carrying a second fluid, an intermediate heat exchanger including at least a portion of the first fluid flow path and at least a portion of the second fluid flow path, and a fluid conveyor associated with the first fluid flow path and the second fluid flow path. The fluid conveyor is configured to convert fluid flow in the first fluid path into mechanical energy to drive fluid flow in the second fluid flow path. The intermediate heat exchanger is configured to facilitate heat transfer between the first fluid flowing through the first fluid flow path and the second fluid flowing through the second fluid flow path.

[0025] In some embodiments, the fluid conveyor includes a turbine positioned in the first fluid flow path and configured to generate mechanical energy in response to fluid flow through the first fluid path, and a pump coupled to the turbine and driven by the mechanical energy generated by the turbine, wherein the pump is configured to drive the second fluid through the second fluid flow path.

[0026] In some embodiments, the pump is powered entirely by the turbine.

[0027] In some embodiments, the turbine is mechanically coupled to the pump. [0028] In some embodiments, the mechanical coupling includes a gear box, a belt, or combinations thereof.

[0029] In some embodiments, the turbine is magnetically coupled to the pump.

[0030] In some embodiments, the pump includes a rotary displacement pump.

[0031] In some embodiments, the pump includes a centrifugal pump.

[0032] In some embodiments, the fluid conveyor includes a membrane pump including a membrane associated with the first fluid flow path and the second fluid flow path, the membrane configured to change state in response to fluid flow through the first fluid flow path. The change in state of the membrane drives the second fluid through the second fluid flow path.

[0033] In some embodiments, the membrane pump further includes at least two valves in the second fluid flow path, the at least two valves configured to open and close in response to the change in state of the membrane.

[0034] In some embodiments, the membrane pump further includes one or more compliance elements configured to absorb abrupt pressure changes in the first fluid flow path.

[0035] In some embodiments, the second fluid flow path is pre-filled with the second fluid.

[0036] In some embodiments, the second fluid is sterile.

[0037] In some embodiments, the second fluid is water-based.

[0038] In some embodiments, the second fluid is a coolant.

[0039] In some embodiments, the system includes a housing containing the intermediate heat exchanger.

[0040] In some embodiments, the housing contains the fluid conveyor.

[0041] In some embodiments, the first fluid flow path is fully isolated from the second fluid flow path.

[0042] In some embodiments, the second fluid flow path includes an inlet port having a sterile connector configured for connection to a patient heat exchanger, and an outlet port having a sterile connector configured for connection to the patient heat exchanger.

[0043] Further details and advantages of the various non-limiting examples described in detail herein will become clear upon reviewing the following detailed description of the various non-limiting examples in conjunction with the accompanying drawing figures. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] FIG. 1 is a schematic view of an extracorporeal blood flow system including an intermediate coolant circuit device in accordance with an embodiment of the present disclosure;

[0045] FIG. 2 is a schematic view of an extracorporeal blood flow system including an intermediate coolant circuit device in accordance with an embodiment of the present disclosure;

[0046] FIG. 3 is a schematic view of an extracorporeal blood flow system including an intermediate coolant circuit device in accordance with an embodiment of the present disclosure;

[0047] FIG. 4 is a schematic view of a magnetic coupling of the extracorporeal blood flow system of any of FIGS. 1-3, in accordance with an embodiment of the present disclosure;

[0048] FIG. 5 is a schematic view of a magnetic coupling of the extracorporeal blood flow system of any of FIGS. 1-3, in accordance with an embodiment of the present disclosure;

[0049] FIG. 6 is a schematic view of an extracorporeal blood flow system including an intermediate coolant circuit device, in a first state, in accordance with an embodiment of the present disclosure;

[0050] FIG. 7 is a schematic view of the extracorporeal blood flow system of FIG. 7, in a second state; and

[0051] FIG. 8 is a schematic view of an extracorporeal blood flow system including an intermediate coolant circuit device in accordance with an embodiment of the present disclosure.

DETAILED DESCRIPTION

[0052] For purposes of the description hereinafter, the terms “upper”, “lower”, “right”, “left”, “vertical”, “horizontal”, “top”, “bottom”, “lateral”, “longitudinal”, and derivatives thereof shall relate to the disclosure as it is oriented in the drawing figures. Spatial or directional terms, such as “left”, “right”, “inner”, “outer”, “above”, “below”, and the like, are not to be considered as limiting as the disclosed embodiments can assume various alternative orientations.

[0053] As used herein, the singular form of “a”, “an”, and “the” include plural referents unless the context clearly dictates otherwise.

[0054] All numbers used in the specification and claims are to be understood as being modified in all instances by the term “about”. The terms “approximately”, “about”, and “substantially” mean a range of plus or minus ten percent of the stated value. [0055] As used herein, the term “at least one of’ is synonymous with “one or more of’. For example, the phrase “at least one of A, B, and C” means any one of A, B, and C, or any combination of any two or more of A, B, and C. For example, “at least one of A, B, and C” includes one or more of A alone; or one or more of B alone; or one or more of C alone; or one or more of A and one or more of B; or one or more of A and one or more of C; or one or more of B and one or more of C; or one or more of all of A, B, and C. Similarly, as used herein, the term “at least two of’ is synonymous with “two or more of’. For example, the phrase “at least two of D, E, and F” means any combination of any two or more of D, E, and F. For example, “at least two of D, E, and F” includes one or more of D and one or more of E; or one or more of D and one or more of F; or one or more of E and one or more of F; or one or more of all of D, E, and F.

[0056] It is also to be understood that the specific devices and processes illustrated in the attached drawings, and described in the following specification, are simply exemplary examples of the disclosure. Hence, specific dimensions and other physical characteristics related to the examples disclosed herein are not to be considered as limiting.

[0057] The terms “first”, “second”, and the like are not intended to refer to any particular order or chronology, but refer to different conditions, properties, or elements.

[0058] The term “at least” is synonymous with “greater than or equal to”. The term “not greater than” is synonymous with “less than or equal to”.

[0059] It is to be understood that the disclosure may assume alternative variations and step sequences, except where expressly specified to the contrary. It is also to be understood that the specific devices and processes illustrated in the attached drawings, and described in the following specification, are simply exemplary aspects of the disclosure. Hence, specific dimensions and other physical characteristics related to the examples disclosed herein are not to be considered as limiting.

[0060] Referring to FIGS. 1-3, an passively driven intermediate circuit device for heat transfer (hereinafter “intermediate circuit device 100”) in accordance with embodiments of the present disclosure is shown. The intermediate circuit device 100 is configured to be mounted between a heater cooler unit (HCU) 200 and a patient heat exchanger 300 (which maybe an integral component of an oxygenator or membrane lung). The intermediate circuit device 100 includes a housing 102 containing two coolant flow paths 110, 120. The first coolant flow path 110 extends from an inlet port 112 to an outlet port 114. The inlet port 112 of the housing 102 is configured for connection to an outlet port 206 of the HCU 200, and the outlet port 114 of the housing 102 is configured for connection to an inlet port 204 of the HCU 200. As such, the second coolant flow path 120 is fluidly connectable to the HCU 200.

[0061] The HCU 200 includes a pump 210 that circulates HCU coolant through an internal fluid circuit (not shown) from the inlet port 204 to the outlet port 206. With the inlet port 112 of the housing 102 connected to the outlet port 206 of the HCU 200, the pump 210 of the HCU 200 pumps HCU coolant out of the HCU 200 and into the first coolant flow path 110 of the intermediate circuit device 100. Similarly, the coolant returns to the HCU 200 via the connection between the outlet port 114 of the housing 102 and the inlet port 204 of the HCU 200. The pump 210 of the HCU 200 is sufficiently powerful to circulate the HCU coolant through the first coolant flow path 110, so the intermediate circuit device 100 need not include an externally powered pump.

[0062] The second coolant flow path 120 extends from an inlet port 122 to an outlet port 124. The inlet port 122 of the housing 102 is configured for connection to an outlet port 306 of the heat exchanger 300, and the outlet port 124 of the housing 102 is configured for connection to an inlet port 304 of the heat exchanger 300. As such, the second coolant flow path 120 is fluidly connectable to the heat exchanger 300.

[0063] The intermediate circuit device 100 includes an intermediate heat exchanger 130 configured to transfer heat between the coolants flowing through the first coolant flow path 110 and the second coolant flow path 120. The heat transfer occurs indirectly - i.e. without mixing of the coolants in each flow path 110, 120 - so that any contaminants present in the coolant of the first coolant flow path 110 are not transferred to the coolant of the second coolant flow path 120. The intermediate heat exchanger 130 may include, for example, at least a portion 132 of the first coolant path 110 and at least a portion 134 of the second coolant path 120. The portions 132, 134 of the coolant flow paths 110, 120 forming the intermediate heat exchanger 130 may be arranged relative to one another in any manner suitable to transfer heat. For example, the portion 134 of the second coolant flow path 120 may include a plurality of flow channels 136 extending through the portion 132 of the first coolant flow path 110 such that the heat from the coolant in the first coolant flow path 110 is transferred through the plurality of flow channels 136 to warm (or cool) the coolant in the second coolant flow path 120.

[0064] The intermediate circuit device 100 includes a fluid conveyor associated with the first coolant flow path 110 and the second coolant flow path 120. The fluid conveyor is configured to convert fluid flow in the first coolant flow path 110 into mechanical energy to drive fluid flow in the second coolant flow path 120. In some embodiments, as illustrated in FIGS. 1-3, the fluid conveyor includes a turbine 150 associated with the first coolant flow path 110 such that fluid flow through the first coolant flow path 110 rotates the turbine 150. The turbine 150 may be located at any position along the first coolant flow path 110, such as downstream of the intermediate heat exchanger 130 as shown in the accompanying drawings. In these embodiments, the fluid conveyor further includes a pump 160 associated with the second coolant flow path 120. The turbine 150 is coupled tothe pump 160, which is configured to circulate coolant through the second coolant flow path 120. The pump 160 may be completely powered by the turbine 150 so that no external power source is required to drive the pump 160. The turbine 150 and/or the pump 160 may be contained within the housing 102. A coupling 170 between the turbine 150 and the pump 160 may be mechanical, magnetic, hydraulic, or another suitable configuration.

[0065] For example, the coupling 170 may include a first gear connected to an output shaft the turbine 150 and a second gear connected to an input shaft of the pump 160. A ratio of the pitch diameter of the first gear to the pitch diameter of the second gear may be 1 : 1 or, in some embodiments, less than 1 : 1 to increase the torque applied to the pump 160, or, in some embodiments, greater than 1 : 1 to increase the rotational speed of the pump 160. The coupling 170 may include additional gears and/or a gearbox to further manipulate the gear ratio between the turbine 150 and the pump 160. In some embodiments, the coupling 170 may include a pair of pulleys respectively connected to an output shaft of the turbine 150 and to the input shaft of the pump 160. A drive belt (e.g. a V-belt or timing belt) may rotationally connect the pulleys of the turbine 150 and the pump 160. A ratio of the pitch diameters of the pulleys may be 1 : 1 or, in some embodiments, less than 1 : 1 to increase the torque applied to the pump 160, or, in some embodiments, greater than 1 : 1 to increase the rotational speed of the pump 160

[0066] In some embodiments, as shown in FIGS. 4 and 5, the coupling 170 may include a magnetic coupling rotationally connecting the output shaft of the turbine 150 to the input shaft of the pump 160 via a magnetic field. The coupling 170 may include a first magnetic rotor 171 rotataionally linked to a second magnetic rotor 172. The first magnetic rotor 171 may, for example, be associated with the turbine 150, while the second magnetic rotor 172 is associated with the pump 160. Rotation of the first magnetic rotor 171 via the turbine 150 drives the second magnetic rotor 172, thereby rotating the pump 160. The first magnetic rotor 171 and the second magnetic rotor 172 may be arranged axially as shown in FIG. 4, radially as shown in FIG. 5, or a combination thereof. In the case of the coupling 170 being magnetic, the turbine 150 and the pump 160 can be structurally isolated from one another (e.g. by arranging the turbine 150 and the pump 160 on opposite sides of a structural member 174) to further isolate the coolant flow path 110, 120 from one another. The magnetic field of the coupling 170 can penetrate the structural member 174 separating the turbine 150 and the pump 160.

[0067] The pump 210 of the HCU 200 induces sufficient energy (i.e. motive force) into the HCU coolant of the first coolant flow path 110 to rotate the turbine 150. In turn, the turbine 150 generates sufficient energy to rotate the pump 160 and thereby circulate the coolant in the second coolant flow path 120. As such, the intermediate circuit device 100 may be entirely passively driven such that no external power supply is required to operate the intermediate circuit device 100. This reduces set up time and allows the intermediate circuit device 100 to be utilized with essentially any commercially available HCU 200 and heat exchanger 300 combination.

[0068] In some embodiments, the fluid conveyor may be a hydraulic displacement pump in which continuous water flow from the HCU 200 drives a two-compartment membrane pump. FIGS. 6 and 7 illustrate such an embodiment. The pump 160 includes a membrane 180 movable between a first state (i.e. a “null” state) shown in FIG. 6 and a second state shown in FIG. 7. The membrane 180 changes between the first and second state in response to a pressure differential between fluid on either side of the membrane 180. In particular, fluid from first coolant flow path 110 occupies a first chamber 182 on one side of the membrane 180, and fluid from the second coolant flow path 120 occupies a second chamber 184 on the other side of the membrane 180. Valves 186, 188 are located at the outlet and inlet, respectively, of the HCU 200, and operate in association with the membrane 180 to control fluid flow through the first coolant flow path 110. As shown in FIGS. 6 and 7, according to one non-limiting aspect or embodiment of the present disclosure, the membrane 180 may include a curved portion that rests in the first chamber 182 when in a first state or “zero position”. It is also contemplated there are alternative methods for achieving a membrane 180 with a “zero position” other than using a curved portion. In particular, a spring (not illustrated) may be attached to the membrane 180 that pulls themembrane 180 during the first state into the “zero position”. It is noted that using an active component instead of the spring (e.g. a motor driven rod attached to the membrane 180) has serious disadvantages due to the need for an additional energy source for the active component, which is typically not desired, and whicih leads to issues with sealing the passage of the rod through the wall of the chamber 182, thereby increasing manufacturing costs.

[0069] As shown in FIG. 6, the valve 186 is closed in the first state to prevent flow from the pump 210 of the HCU 200 into the first chamber 182. In the first state of FIG. 6, the pressure in the second chamber 184 exceeds pressure in the first chamber 182. In one non-limitnig aspect or embodiment of the present disclosure, the membrane 180 is configured to adopt a curved shape when in the first state or “zero position”. The curved shape of the membrane 180 in this “zero position” is free of pressure, but has a curved portion that extends towards and/or into the first chamber 182. In one example, the main force which brings the membrane 180 into the “zero-position” is the inherent (“normal”) curved shape of the membrane 180 itself.

[0070] Referring to FIG. 7, when the valve 186 opens and the valve 188 closes, the pump 210 is able to pressurize the first chamber 182. When the pressure in the first chamber 182 exceeds the pressure in the second chamber 184, the curved portion of the membrane 180 inverts and pushes into the second chamber 184. Inversion of the membrane 184 forces the curved portion of the membrane 180 into the second chamber 184 to reduce the volume of the second chamber 184, thus forcing the fluid in the second chamber 184 out of the second chamber 184 and into the second coolant flow path 120. Check valves 190, 192 at the inlet and outlet, respectively, of the second chamber 184 force the fluid exiting the second chamber 184 to flow in a constant direction through the second coolant flow path 120. This process of the membrane 180 changing state repeats as long as the pump 210 of the HCU 200 is actuated, casuing the fluid in the second coolant flow path 120 to cycle through the intermediate heat exchanger 130 and transfer heat to/from the HCU coolant in the first coolant flow path 110.

[0071] As explained above, opening and closing of the valves 186, 188 must be timed with the changing state of the membrane 180 to control flow through the coolant flow paths 110, 120. To facilitate this timing, the valves 186, 188 may be electronically atuated by a controller which detects the state of the membrane 180 and actuates the valves 186, 188 in the sequence described above based on the state of the membrane 180. In other embodiments, the membrane 180 may be mechanically coupled (e.g. via various linkages) to the valves 186, 188 such that the valves 186, 188 are passively actuated as the membrane 180 changes state. The system may further include one or more compliance elements in the first flow path 110 configured to absorb abrupt pressure changes in the first flow path 100 caused by the opening and closing of the vavles 186, 188.

[0072] The intermediate circuit device 100 may be retrofitted into existing extracorporeal circulation systems using the existing ports 204, 206, 304, 306 of the HCU 200 and the heat exchanger 300. In such systems, the heat exchanger 300 may be originally configured to connect directly (or via tubing) to the HCU 200 by connecting the inlet port 304 of the heat exchanger 300 to the outlet port 206 of the HCU 200, and connecting the outlet port 306 of the heat exchanger 300 to the inlet port 204 of the HCU 200. The intermediate circuit device 100 may be retrofitted to such a system by instead connecting the inlet port 204 of the HCU 200 to the outlet port 114 of the intermediate circuit device 100, connecting the outlet port 206 of the HCU 200 to the inlet port 112 of the intermediate circuit device 100, connecting the inlet port 304 of the heat exchanger 300 to the outlet port 124 of the intermediate circuit device 100, and connecting the outlet port 306 of the heat exchanger 300 to the inlet port 122 of the intermediate circuit device 100. In some embodiments, the ports 112, 114, 122, 124 of the intermediate circuit device 100 may include standardized fittings (e.g. quick connectors) configured for connection to the corresponding ports 204, 206, 304, 306 of the HCU 200 and the heat exchanger 300.

[0073] As such, the intermediate circuit device 100 may be connected directly to the HCU 200 and the heat exchanger 300 without the need for an adaptor(s) or other interfacing component. Moreover, the ports 112, 114, 122, 124 of the intermediate circuit device 100 may be configured for connection to the corresponding ports 204, 206, 304, 306 of the HCU 200 and the heat exchanger 300 without the need for special tools, decreasing setup time and complexity. In some embodiments, the intermediate circuit device 100 may be connected to the ports 204, 206, 304, 306 of the HCU 200 and the heat exchanger 300 via tubing to allow remote mounting of the intermediate circuit device 100 where space is limited or remote mounting is otherwise desired.

[0074] The HCU coolant used in the first coolant flow path 110 may be any fluid recommended for use in the HCU 200. For example, the HCU coolant in the first coolant flow path 110 may include an antimicrobial recommended for use in commercially available embodiments of the HCU 200, such as the Maquet HU 35 and/or the Maquet HCU 40. Other examples of coolants suitable for use in the HCU 200 are described in U.S. Patent Application Publication No. 2017/0267907, the disclosure of which is hereby incorporated by reference in its entirety.

[0075] The coolant in the second coolant flow path 120 may be a bio-inert/biocompatible fluid. In some embodiments, the coolant in the second coolant flow path 120 is water-based (such as sterile water). In some embodiments, the coolant in the second coolant flow path 120 is different from the fluid in the first coolant flow path 110. The coolant in the first coolant flow path 110 may include significantly more aggressive antimicrobial, as there is no risk of blood contamination.

[0076] The second coolant flow path 120 may be prefilled with the appropriate coolant so that the intermediate circuit device 100 may be used immediately upon connection to the HCU 200 and the heat exchanger 300. In some embodiments, the second coolant flow path 120 may include or may be arranged in line with a bubble trap 400 for purging air from the second coolant flow path 120.

[0077] During operation of the extracorporeal circulation system, the patient’s blood is isolated within the heat exchanger 300, while the HCU coolant in the first coolant flow path 110 is isolated within the intermediate circuit device 100 and the HCU 200. Thus, the blood is never in a position to be contaminated by the HCU coolant. Rather, the HCU coolant in the first coolant flow path 110 transfers heat to and/or from the coolant in the second coolant flow path 120 within the intermediate heat exchanger 130 of the intermediate circuit device 100. The coolant in the second coolant flow path 120 then transfers heat to and/or from the blood in the heat exchanger 300. Thus, heat transfer from the HCU coolant to the blood occurs indirectly with the coolant in the second coolant flow path 120 acting as an intermediary heat transfer medium. In the event that the coolant in the second coolant flow path 120 becomes contaminated by the HCU coolant in the first coolant flow path (for example, due to leakage, etc. of the HCU coolant), the blood is still isolated from the coolant in the second coolant flow path 120 by the internal structure of the heat exchanger 300. However, such contamination is unlikely due to the tight-fitting walls within the intermediate heat exchanger 130. In particular, the walls of the intermediate heat exchanger 130 may be made of metal, since biocompatibility is not required within the intermediate heat exchanger 130. Importantly, the construction of the intermediate heat exchanger 130 is such that the first coolant flow path 110 is fully isolated from the second coolant flow path 120, and no fluid transfer can occur between the first and second coolant flow paths 110, 120. This is in contrast to the heat exchanger 300, which may not achieve perfect fluid isolation.

[0078] In some embodiments, the intermediate circuit device 100 may be configured for connection to the heat exchanger 300 under non-sterile conditions. Such a connection is referred to herein as “germ free”. In some embodiments, the intermediate circuit device 100 may be configured for connection to the heat exchanger 300 under sterile conditions. For example, the intermediate circuit device 100 may be supplied pre-connected to the heat exchanger 300 and prefilled with coolant in the second coolant flow path 120. Such a connection is referred to herein as “sterile”. A sterile connection may also include sterile connectors (e.g. Kleenpak™ or AseptiQuik® connectors) at the inlet and outlet ports 112, 114, 122, 124.

[0079] In some embodiments, the intermediate circuit device 100 may be configured as a disposable component intended for a predetermined number of usages. For example, the intermediate circuit device 100 may be intended for use during a single extracorporeal circulation procedure. As the intermediate circuit device 100 is discarded after a single use (or after a predetermined number of uses), the potential for contamination of the blood by the coolant in the second coolant flow path 120 is minimized. In some embodiments, the coolant in the second coolant flow path 120 does not include disinfectants or other compounds that could be harmful if inadvertently introduced into the blood. If the coolant in the second coolant flow path 120 is discarded after each use (or a relatively small number of uses), the potential for the coolant developing contaminants that could be transmitted to the blood is significantly reduced. Thus, the need for disinfectants that could be harmful if leaked into the blood is reduced or eliminated.

[0080] Furthermore, if the intermediate circuit device 100 is discarded after a single use (or after a predetermined number of uses), the internal structure of the intermediate circuit device 100 (for example, the intermediate heat exchanger 130) is less likely to develop structural defects from sustained use that could allow internal leakage between the coolant flow paths 110, 120. Thus, the likelihood of blood becoming contaminated by the coolant in the second coolant flow path 120 is reduced by the disposal of the intermediate circuit device 100 after the predetermined number of uses has occurred.

[0081] The entire intermediate circuit device 100 including the housing 102; the ports 112, 114, 122, 124; the coolant flow paths 110, 120; the turbine 150; and the pump 160 may be disposed of as a unit to provide the maximum protection against contamination of the blood. The housing 102 may be formed as a unitary component or from a plurality of permanently joined components so that the device 100 cannot be deconstructed without destroying the device 100. This enforces disposal of the device 100 as a complete unit and prevents operators from attempting to reuse individual parts of the device 100. To facilitate disposal of the intermediate circuit device 100, the components thereof may be constructed from readily available, inexpensive, and easily disposable/recyclable materials where possible. For example, the housing 102, the coolant flow paths 110, 120, the turbine 150 and the pump 160 may be made from plastic (e.g. polycarbonate (PC), polyethlyen (PE), polyamid (PA), polypropylene (PP), polysulfone, POM, polyurethane (PU) and polyethylene terephthalate (PET)). The components of the intermediate circuit device 100, particularly those which contact the coolants, must also be made from sterile materials that do not introduce contaminants into the coolant that could ultimately transfer to the blood.

[0082] The HCU 200 and/or the components with a usage life significantly longer than the intermediate circuit device 100. As such, the HCU 200 may be used repeatedly in contrast to the intermediate circuit device 100, which is used only a predetermined number of time (e.g. once). The heat exchanger 300 is configured to for a single use like the intermediate circuit device 100.

[0083] In some embodiments, the coolant in the second coolant flow path 120 may include compounds which are able to permeate a membrane of the heat exchanger 300 that separates the coolant from the blood. Thus, in addition to transferring heat, the coolant in the second coolant flow path 120 may be used to transfer compounds to and/or from the blood within the heat exchanger 300. Heat exchanger membranes may be made of the polyurethane (PU) or polyethylene terephthalate (PET), so compounds intended be transferred to and or from the blood may be able to permeate these materials. Examples of such compounds include electrolytes, drugs, and more generally any substance having molecules small enough to pass through the heat exchanger membranes.

[0084] In some embodiments, a flow rate and temperature of the coolant in the second coolant flow path 120 can be derived from known flow rate and temperature characteristics of the HCU coolant in the first coolant flow path 110. For example, the flow rate of the coolant in the second coolant flow path 120 can be derived from the equation F2 =/(Fl), where F2 is flow rate of the coolant in the second coolant flow path 120, Fl is the flow rate of the HCU coolant in the first coolant flow path 110, and /is a function known for steady-state flow of coolant. Similarly, the temperature of the coolant in the second coolant flow path 120 can be derived from the equation T2 = g(Tl), where T2 is temperature of the coolant in the second coolant flow path 120, T1 is the temperature of the HCU coolant in the first coolant flow path 110, and g is a function known for steady-state temperature of coolant. / and g may be transfer functions, so that F2 and T2 can be readily known from Fl and Tl.

[0085] The ability to derive temperature and flow rate of the coolant in the second coolant flow path 120 allows the operator to accurately predict the heating/cooling effect of the coolant in the second coolant flow path 120 without the need for additional sensors and software.

[0086] Referring now to FIG. 8, another embodiment of the intermediate circuit device 100 is illustrated in which there is no general housing equivalent to the housing 102 of the embodiments of FIGS. 1-3. In some embodiments, a mounting bracket 104 may be provided to rigidly locate the turbine 150, the pump 160, and the intermediate heat exchanger 130 relative to one another. The remaining components shown in FIG. 8 are substantially identical to like comopnoents of the embodiments of FIGS. 1-3.

[0087] In some embodiments, the intermediate circuit device 100 may be a disposable device for use on a single patient during a single procedure. In other embodiments, the intermediate circuit device 100 may be a sterilizable component that can be reused over multiple procedures and/or patients when properly sterilized. While the foregoing description has generally described the device 100 in the application of cooling, the system and device 100 could equally be used for warming/heating as the heat transfer within the intermediate heat exchanger 130 is a passive function of the temperature differential between the HCU coolant in the first coolant flow path 110 and the fluid in the second coolant flow path 120.

[0088] While various examples of the present disclosure were provided in the foregoing description, those skilled in the art may make modifications and alterations to these examples without departing from the scope and spirit of the disclosure. For example, it is to be understood that features of various embodiments described herein may be adapted to other embodiments described herein. Accordingly, the foregoing description is intended to be illustrative rather than restrictive. The disclosure described hereinabove is defined by the appended claims, and all changes to the disclosure that fall within the meaning and the range of equivalency of the claims are to be embraced within their scope.

Claims

WE CLAIM:

1. An intermediate circuit device for heat transfer for an extracorporeal circulation system, the device comprising: a first fluid flow path for carrying a first fluid; a second fluid flow path for carrying a second fluid; an intermediate heat exchanger including at least a portion of the first fluid flow path and at least a portion of the second fluid flow path; and a fluid conveyor associated with the first fluid flow path and the second fluid flow path, wherein the fluid conveyor is configured to convert fluid flow in the first fluid path into mechanical energy to drive fluid flow in the second fluid flow path, and wherein the intermediate heat exchanger is configured to facilitate heat transfer between the first fluid flowing through the first fluid flow path and the second fluid flowing through the second fluid flow path.

2. The intermediate circuit device of claim 1, wherein the fluid conveyor comprises: a turbine positioned in the first fluid flow path and configured to generate mechanical energy in response to fluid flow through the first fluid path; and a pump coupled to the turbine and driven by the mechanical energy generated by the turbine, wherein the pump is configured to drive the second fluid through the second fluid flow path.

3. The intermediate circuit device of claim 2, wherein the pump is powered entirely by the turbine.

4. The intermediate circuit device of claim 2, wherein the turbine is mechanically coupled to the pump.

5. The intermediate circuit device of claim 4, wherein the mechanical coupling comprises a gear box, a belt, or combinations thereof.

6. The intermediate circuit device of claim 2, wherein the turbine is magnetically coupled to the pump.

7. The intermediate circuit device of claim 2, wherein the pump comprises a rotary displacement pump.

8. The intermediate circuit device of claim 2, wherein the pump comprises a centrifugal pump.

9. The intermediate circuit device of claim 1, wherein the fluid conveyor comprises a membrane pump, the membrane pump comprising: a membrane associated with the first fluid flow path and the second fluid flow path, the membrane configured to change state in response to fluid flow through the first fluid flow path, wherein the change in state of the membrane drives the second fluid through the second fluid flow path.

10. The intermediate circuit device of claim 9, wherein the membrane pump further comprises: at least two valves in the second fluid flow path, the at least two valves configured to open and close in response to the change in state of the membrane.

11. The intermediate circuit device of claim 9, wherein the membrane pump further comprises one or more compliance elements configured to absorb abrupt pressure changes in the first fluid flow path.

12. The intermediate circuit device of claim 1, wherein the second fluid flow path is pre-filled with the second fluid.

13. The intermediate circuit device of claim 12, wherein the second fluid is sterile.

14. The intermediate circuit device of claim 12, wherein the second fluid is water-based.

15. The intermediate circuit device of claim 12, wherein the second fluid is a coolant.

16. The intermediate circuit device of claim 1, further comprising a housing containing the intermediate heat exchanger.

17. The intermediate circuit device of claim 16, wherein the housing contains the fluid conveyor.

18. The intermediate circuit device of claim 1, wherein the first fluid flow path is fully isolated from the second fluid flow path.

19. The intermediate circuit device of claim 1, wherein the second fluid flow path comprises: an inlet port having a sterile connector configured for connection to a patient heat exchanger, and an outlet port having a sterile connector configured for connection to the patient heat exchanger.

20. An extracorporeal circulation system, comprising: a heater cooler unit; a patient heat exchanger; and an intermediate circuit device for heat transfer, comprising: a first fluid flow path fluidly connected to the heater cooler unit and carrying a first fluid; a second fluid flow path fluidly connected to the patient heat exchanger and carrying a second fluid; an intermediate heat exchanger including at least a portion of the first fluid flow path and at least a portion of the second fluid flow path; and a fluid conveyor associated with the first fluid flow path and the second fluid flow path, wherein the fluid conveyor is configured to convert fluid flow in the first fluid path into mechanical energy to drive fluid flow in the second fluid flow path, and wherein the intermediate heat exchanger is configured to facilitate heat transfer between the first fluid flowing through the first fluid flow path and the second fluid flowing through the second fluid flow path.

21. The system of claim 20, wherein the fluid conveyor comprises: a turbine positioned in the first fluid flow path and configured to generate mechanical energy in response to fluid flow through the first fluid path; and a pump coupled to the turbine and driven by the mechanical energy generated by the turbine, wherein the pump is configured to drive the second fluid through the second fluid flow path.

22. The system of claim 21, wherein the pump is powered entirely by the turbine.

23. The system of claim 21, wherein the turbine is mechanically coupled to the pump.

24. The system of claim 23, wherein the mechanical coupling comprises a gear box, a belt, or combinations thereof.

25. The system of claim 21, wherein the turbine is magnetically coupled to the pump.

26. The system of claim 21, wherein the pump comprises a rotary displacement pump.

27. The system of claim 21, wherein the pump comprises a centrifugal pump.

28. The system of claim 20, wherein the fluid conveyor comprises a membrane pump, the membrane pump comprising: a membrane associated with the first fluid flow path and the second fluid flow path, the membrane configured to change state in response to fluid flow through the first fluid flow path, wherein the change in state of the membrane drives the second fluid through the second fluid flow path.

29. The system of claim 28, wherein the membrane pump further comprises: at least one valve in the second fluid flow path, the at least one valve configured to open and close in response to the change in state of the membrane.

30. The system of claim 28, wherein the membrane pump further comprises one or more compliance elements configured to absorb abrupt pressure changes in the first fluid flow path.

31. The system of claim 20, wherein the second fluid flow path is pre-filled with the second fluid.

32. The system of claim 31, wherein the second fluid is sterile.

33. The system of claim 31, wherein the second fluid is water-based.

34. The system of claim 31, wherein the second fluid is a coolant.

35. The system of claim 20, further comprising a housing containing the intermediate heat exchanger.

36. The system of claim 35, wherein the housing contains the fluid conveyor.

37. The system of claim 20, wherein the first fluid flow path is fully isolated from the second fluid flow path.

38. The system of claim 20, wherein the second fluid flow path comprises: an inlet port having a sterile connector configured for connection to a patient heat exchanger, and an outlet port having a sterile connector configured for connection to the patient heat exchanger.