Perfusion System with Heat Exchanger

Abstract

A method of controlling thermal transfer in a perfusion system heat exchanger of an extracorporeal fluid treatment device for conditioning an extracorporeal patient fluid for administration to a patient comprises a step of providing a perfusion system heat exchanger, wherein the perfusion system heat exchanger comprises a first fluid passage for a liquid heat transfer medium and a second fluid passage for the extracorporeal patient fluid to be temperature-controlled via exchange of thermal energy with the heat transfer medium, and a step of providing the heat transfer medium through the first fluid passage. The heat transfer medium comprises a component with anti-microbial properties, such as glycol. The provision of antimicrobial fluid reduces the risk of microbe contamination of the extracorporeal fluid, and hence the risk of clinical complications.

Claims

1. A perfusion system comprising: a heater-cooler device for heating and/or cooling a heater-cooler fluid; a perfusion system heat exchanger for controlling the temperature of a fluid as the fluid flows through a blood processing device; and an intermediate heat exchanger between the heater-cooler device and an intermediate passage, wherein the heater-cooler device is provided to supply heater-cooler fluid to the intermediate heat exchanger, the intermediate passage is provided for an intermediate fluid to be supplied to the perfusion system heat exchanger, wherein the intermediate heat exchanger permits heat exchange between the heater-cooler fluid and the intermediate fluid, whereby the heater-cooler fluid is fluidically isolated from the perfusion system heat exchanger, and wherein the intermediate fluid and/or the heater-cooler fluid is antimicrobial fluid.

2. The perfusion system in accordance with claim 1, wherein the intermediate heat exchanger is integral with the intermediate passage.

3. The perfusion system in accordance with claim 1, wherein the intermediate heat exchanger comprises a first heat exchange element for integration with the heater-cooler device and a second heat exchange element integral with the intermediate passage.

4. The perfusion system in accordance with claim 1, wherein the intermediate heat exchanger and/or the intermediate passage is detachable from the heater-cooler device.

5. The perfusion system in accordance with claim 2, wherein the intermediate heat exchanger and/or the intermediate passage comprises an arrangement preventing re-attachment to a heater-cooler device.

6. The perfusion system in accordance with claim 1, wherein the intermediate heat exchanger and/or the intermediate passage comprises a quick-connect mechanism for fluid connection with the heater-cooler device and/or for fluid connection with the perfusion system heat exchanger.

7. The perfusion system in accordance with claim 6, wherein the quick-connect mechanism comprises a self-sealing membrane.

8. The perfusion system in accordance with claim 1, further comprising a flow-control arrangement for controlling the flow rate of either or both of the heater-cooler fluid and the intermediate fluid.

9. The perfusion system in accordance with claim 8, wherein the flow-control arrangement comprises a roller pump, a centrifugal pump, or a centrifuge impeller arrangement for use with an external drive.

10. The perfusion system in accordance with claim 1, further comprising one or more non-return valves in the intermediate passage or in a heater-cooler conduit supplying the heater-cooler fluid.

11. The perfusion system in accordance with claim 1, further comprising a flow sensor arrangement for determining the flow rate of the heater-cooler fluid, of the intermediate fluid, and/or an extracorporeal patient fluid passing through the perfusion system heat exchanger.

12. The perfusion system in accordance with claim 1, further comprising a temperature sensor arrangement for determining the temperature of the heater-cooler fluid, of the intermediate fluid, and/or an extracorporeal patient fluid passing through the perfusion system heat exchanger.

13. The perfusion system in accordance with claim 1, wherein the intermediate heat exchanger and/or the intermediate passage comprises a fill port.

14. The perfusion system in accordance with claim 1, wherein the heater-cooler fluid is antimicrobial fluid and the intermediate fluid is water.

15. The perfusion system in accordance with claim 1, wherein the blood processing device is an oxygenator.

16. The perfusion system in accordance with claim 1, wherein the blood processing device is a cardioplegic agent delivery system.

17. The perfusion system in accordance with claim 1, wherein the antimicrobial fluid is biocidal.

18. The perfusion system in accordance with claim 17, wherein the antimicrobial fluid comprises glycol.

19. The perfusion system in accordance with claim 18, wherein the glycol comprises propylene glycol or ethylene glycol.

20. The perfusion system in accordance with claim 1, wherein the perfusion system heat exchanger is part of a system capable of operating at sub-atmospheric pressure.

21. The perfusion system in accordance with claim 4, wherein the intermediate heat exchanger and/or the intermediate passage is disposable.

Description

DESCRIPTION OF THE FIGURES

[0146] Exemplary embodiments of the invention will now be described with reference to the Figures, in which:

[0147] FIG. 1 shows a schematic arrangement of components of a prior art heater-cooler arrangement;

[0148] FIG. 2 shows a schematic arrangement of components of a heater-cooler apparatus in accordance with an exemplary embodiment of the present invention;

[0149] FIG. 3 shows a schematic arrangement of components of a heater-cooler apparatus in accordance with another exemplary embodiment of the present invention;

[0150] FIG. 4 shows a schematic arrangement of a heat transfer device in accordance with an exemplary embodiment of the present invention;

[0151] FIG. 5 shows a schematic arrangement of a heat transfer device in accordance with another exemplary embodiment of the present invention;

[0152] FIGS. 6 and 7 show a partially transparent isometric view and a section view, respectively, of a heat transfer device in accordance with another exemplary embodiment of the present invention;

[0153] FIG. 8 shows an isometric view of components of a heater-cooler apparatus in accordance with an exemplary embodiment of the present invention;

[0154] FIG. 9 shows steps of an exemplary sequence of method steps of a control method for controlling the temperature using a heater-cooler system in accordance with embodiments of the present invention; and

[0155] FIG. 10 shows steps of an exemplary sequence of method steps of a method of controlling thermal transfer in a perfusion system heat exchanger in accordance with embodiments of the present invention.

DESCRIPTION

[0156] FIG. 1 shows, schematically, a prior art heater-cooler system for use with a perfusion system. The heater-cooler system comprises a heater-cooler device 10 with a heater 12 and a cooler 14. The heater 12 and the cooler 14 are used to set the temperature of a heater-cooler fluid 11. The heater-cooler fluid 11 is, via a supply port 18, circulated to a perfusion system heat exchanger, and returned to the heater-cooler device via a return port 16.

[0157] The perfusion system heat exchanger is illustrated as an integral component of an oxygenator 20. The oxygenator 20 comprises a blood line 22 which flows blood via an oxygenation membrane 28 for exposure to an oxygenation gas from an oxygen supply line 24. Before oxygenation in the oxygenator, the blood is in a condition 22A. After oxygenation, the blood leaves the oxygenator in a condition 22B. Condition 22B may be a condition in which the blood is oxygenated for administration to a patient. Oxygenation gas in the oxygen supply line 24 is supplied in a condition 24A and exits the oxygenator as exhaust gas in a condition 24B.

[0158] The oxygenator 20 comprises an integral, or associated, heat exchanger 26 positioned along the blood line 22, upstream of the oxygenation membrane 28. The heater-cooler fluid 11 is circulated from the supply port 18 into the heat exchanger 26 via an inlet 32 to set the temperature of the blood in line 22. The heater-cooler fluid 11 leaves the heat exchanger 26 via an outlet 34 and is circulated back to the heater-cooler device 10 via the return port 16.

[0159] The FIG. 1 system allows the temperature of the blood in the condition 22B to be controlled by flowing the heater-cooler fluid 11 from the heater-cooler device 10 through the heat exchanger 26, whereby the heater-cooler fluid 11 comes into contact with the heat exchanger 26.

[0160] FIGS. 2 and 3 each show an exemplary embodiment of the invention. In FIGS. 2 and 3, the same numerals are used for components that correspond to those described in FIG. 1.

[0161] In FIG. 2, a heater-cooler apparatus 1 comprises a heater-cooler device 10 comprising a heater 12 and a cooler 14 which are used to set the temperature of a heater-cooler fluid 11 circulated via a supply port 18 and to be returned via a return port 16. An oxygenator 20 is provided to generate oxygenated blood 22B from oxygen-reduced blood 22A in a blood line 22 by exposure, via an oxygenation membrane 28, to oxygenation gas supplied via an oxygen supply line 24 in a condition 24A and to leave the oxygenator 20 as exhaust gas 24B.

[0162] In order to control the temperature of the blood in condition 22B to be suitable for subsequent administration to a patient, the oxygenator 20 comprises a heat exchanger 26 constituting a perfusion system heat exchanger comprising an inlet 32 for receiving a heat transfer fluid and an outlet 34 to allow heat transfer fluid to circulate away.

[0163] The system of FIG. 2 comprises an intermediate passage 30 in which an intermediate fluid 31 can be circulated. The intermediate passage 30 runs through a heat exchanger 40, which constitutes an intermediate heat exchanger of the intermediate passage. The heat exchanger 40 comprises a heater-cooler passage 46 with an entry port 36 and an exit port 38. The entry port 36 is provided for fluid connection with the supply port 18 from the heater-cooler device 10. The exit port 38 is provided for fluid connection with the return port 16 of the heater-cooler device 10.

[0164] The heater-cooler passage 46 and the intermediate passage 30 permit heat transfer between the intermediate fluid 31 and the heater-cooler fluid 11, while fluidically isolating the heater-cooler fluid 11 from the intermediate fluid 31. Thus, the heater-cooler fluid 31 may be constituted by a substance that may otherwise be harmful to the coils of the heat exchanger 26. The heat exchanger 40 may be part of a disposable system and any detrimental effect of the heater-cooler fluid 31 on the heat exchanger 40 is more tolerable than on the heat exchanger 26.

[0165] The intermediate fluid 31 is circulated through the heat exchanger 26 via the inlet 32 and the outlet 34, to control the temperature of the blood in the blood line 22.

[0166] The intermediate passage 30 comprises a pump 44 to control the flow rate of the intermediate fluid 31. The pump 44 constitutes a flow-control arrangement. The pump 44 may be controlled by a controller (not shown) and may be part of a closed-loop control system comprising a flow-sensor arrangement to maintain a set flow rate.

[0167] In addition, the intermediate passage comprises a fill port 42 to permit intermediate fluid 31 to be added and/or removed. The fill port 42 may be constituted by a suction/vent arrangement.

[0168] In FIG. 2, the fill port 42 and the pump 44 are indicated on the upper limb, downstream of the outlet 34. Either or both may be located on the lower limb, upstream of the inlet 32.

[0169] The connections of the entry port 36 and the exit port 38 may comprise quick-connect mechanisms, to facilitate installation and removal of the intermediate circuit 30. For instance, a quick-connect mechanism may comprise self-sealing membranes. The entry port 36 may be configured for attachment to the supply port 18, and the exit port 38 may be configured for attachment to the return port 16.

[0170] FIG. 3 shows an alternative embodiment in the form of a heater-cooler apparatus 2 in which the heat exchanger 40 comprises two attachable plates constituting a quick-connect mechanism. The heater-cooler device 10 is provided with a first heat exchanger plate 40a. The intermediate passage 30 comprises a second heat exchanger plate 40b. The first and second heat exchanger plates 40a and 40b can be coupled, and as shown in FIG. 3 are coupled, to make up the heat exchanger 40. The heat transfer is improved by a paste 40c applied between the plates. The use of the paste 40c is optional. Other mechanisms to improve the heat transfer between the first and second heat exchanger plates 40a and 40b may be used.

[0171] The heat exchanger 40 comprised of the first and second heat exchanger plates 40a and 40b of the FIG. 3 arrangement provides a similar fluid-isolation arrangement as that in FIG. 2: a heater-cooler passage 46 runs through the first heat exchanger plate 40a from an entry port 36 to an exit port 38. The entry port 36 is coupled with the supply port 18 of the heater-cooler device 10, and the exit port 38 is coupled with the return port 16. The coupling may be permanent, such that the first heat exchanger plate 40a is integral with the heater-cooler device 10. The intermediate passage 30 passes through the second heat exchanger plate 40b. When assembled, the intermediate fluid 31 is in thermal contact with the heater-cooler fluid 11 while being fluidically isolated.

[0172] The intermediate passage 30 may, together with the heat exchanger 40 (as shown in the FIG. 2 embodiment), or together with the second heat exchanger plate 40b (as shown in the FIG. 3 embodiment), be comprised in a disposable heat exchanger. This reduces the need for post-treatment sterilisation of the intermediate passage 30.

[0173] The description of an oxygenator 20 is exemplary for a treatment device. The heater-cooler fluid 11 may be provided to the heat exchanger of any other extracorporeal line, such as, e.g., of a cardioplegia line, or of a stand-alone heat exchanger.

[0174] The provision of a pump 44 is exemplary. Other means of controlling the flow of the intermediate fluid 31 relative to the flow rate of the heater-cooler fluid 11 may be used. The pump 44 may be constituted by a centrifugal pump that is integral with the intermediate passage 30. The pump 44 may be constituted by a centrifugal pump impeller arrangement that is integrated into the disposable system, intended to be driven by an external driver of the heater-cooler system. The integrated impeller and the external driver may be configured for magnetic coupling. Other pump types may be used, and in that case, the intermediate passage 30 may comprise tubing or characteristics that render it suitable for use with a pump type. For instance, the pump 44 may be constituted by a roller pump. The roller pump may be part of a heater-cooler control system but not part of a disposable system. To be suitable for a roller pump, the intermediate passage 30 may comprise a tubing section of sufficient length and flexibility for use with a roller pump.

[0175] The heater-cooler apparatus 1 and 2 are illustrated using a single intermediate passage 30 to supply a heat exchanger 26. The heater-cooler device 10 may be configured to simultaneously supply heater-cooler fluid for more than one heat exchanger. For instance, the heater-cooler fluid may be simultaneously supplied for an oxygenation line, a cardioplegia line, and/or a patient temperature control mat. In that case, several intermediate passages may be provided to permit simultaneous heat coupling of the intermediate passages with the heater-cooler device. For instance, two intermediate passages may be provided, one for an oxygenation line heat exchanger, and one to for a cardioplegia line heat exchanger. The heater-cooler device may be configured with a common return line from multiple intermediate passages.

[0176] FIGS. 4 and 5 illustrate heat transfer devices 301 and 302, respectively, which may each be used as disposable (or “consumable”) components. The heat transfer device 301 of FIG. 4 corresponds to that used in the FIG. 2 heat transfer device 1. The heat transfer device 302 of FIG. 5 corresponds to that used in the FIG. 3 heat transfer device 2.

[0177] For ease of reference, the same numerals are used in FIGS. 4 and 5 as they are used in the preceding Figures for corresponding components. The heat transfer device 301 comprises tubing 41 constituting a first conduit leading through an integrated heat exchanger 40 constituting a heat exchange element. At one end, the tubing 41 comprises a heat exchanger inlet connection 33; at the other end the tubing 41 comprises a heat exchanger outlet connection 35. The heat exchanger connections constitute connections for attachment to a heat exchanger inlet and outlet, respectively, such as the inlet 32 and outlet 34 indicated in FIG. 2. When installed, the tubing 41 provides an intermediate passage 30 through the heat exchanger 40 and a perfusion system heat exchanger. The heat exchanger 40 further comprises a heater-cooler passage 46 constituting a second conduit with an entry port 36 and an exit port 38 for connection to a heater-cooler device.

[0178] The heat transfer device 301 comprises, along a length of the tubing 41, a fill port 42 and an integral pump 44. Instead of the pump 44, the tubing 41 may comprise a pump component for use with an external driver or a section of suitable characteristics for use with an external pump. For instance, the tubing 41 may comprise a section of sufficient length and flexibility for use with an external roller pump, or a centrifugal pump impeller arrangement for use with an external driver.

[0179] When installed to a heater-cooler device, temperature-controlled heater-cooler fluid may run via passage 46 to exchange heat with the intermediate fluid in the intermediate passage 30, as explained above, while fluidically isolating the heater-cooler fluid from the intermediate fluid and from the perfusion system heat exchanger.

[0180] The heat transfer device 302 shown in FIG. 5 comprises a heat exchanger plate 40b constituting a heat exchange element. The heat exchanger plate 40b is configured for coupling with a first heat exchanger plate 40a, which is configured for attachment to a heater-cooler device, in the manner described with reference to FIG. 3. The two plates 40a and 40b together provide heat transfer functionality from the heater-cooler fluid to an intermediate fluid while fluidically isolating the two fluids.

[0181] FIGS. 6 and 7 show a partially transparent isometric view and a section, respectively, of a heat transfer device 303 akin to the heat transfer device 301 shown in FIG. 4. The same reference numerals are used for equivalent elements in FIGS. 4, 6 and 7. The heat transfer device 303 comprises an entry port 36 and an exit port 38 for a heater-cooler fluid to be provided from a heater-cooler device to the intermediate heat exchanger 40 of the heat transfer device 303.

[0182] The heat transfer device 303 comprises an intermediate passage 30 leading from a heat exchanger inlet connection 33 to and heat exchanger outlet connection 35. The heat transfer device 303 comprises an impeller arrangement 45 of a centrifuge impeller, constituting a pump 44. The impeller arrangement 45 comprises a magnet 47 and an impeller 48 to be driven by an external drive mechanism, such as an electric motor (the external drive is not shown in FIGS. 6 and 7). When coupled with the external drive mechanism, the impeller arrangement 45 pumps the intermediate fluid from the inlet connection 33 to the outlet connection 35.

[0183] By virtue of quick-connect mechanisms, the entry port 36 and the exit port 38 can be detached from a heater-cooler device, and the inlet connection 33 and the outlet connection 35 can be detached from a perfusion system heat exchanger, such that the heat transfer device 303 is detachable from a heat exchange apparatus. The detached heat transfer device 303 can be disposed, avoiding the need for its sterilisation.

[0184] In embodiments, the heat transfer device 303 is intended for re-use and can be sterilised. In that case, the sterilisation can be performed independently of the operation of the heater-cooler device, e.g., off-site, without requiring sterilisation of the entire heater-cooler device.

[0185] As shown in FIG. 7, the entry port 36 comprises a ball sealing valve 361 constituting a non-return valve. Likewise, the exit port 38 comprises a ball sealing valve 381 constituting a non-return valve. The non-return valves help to contain heater-cooler fluid after disconnection of the heat transfer device 303. This reduces the risk of spillage of heater-cooler fluid, particularly when the heat transfer device 303 is detached quickly from the heater-cooler device. Likewise, the non-return valves may be provided in the inlet connection 33 or in the outlet connection 35, to help to contain non-sterile intermediate fluid.

[0186] FIG. 8 shows some of the components of a heater-cooler apparatus 3 comprising a heater-cooler device 10. The heater-cooler apparatus 3 corresponds conceptually to the heater-cooler apparatus 1 described above but may be coupled with two heat transfer devices 303a and 303b, each corresponding to the description of heat transfer device 303 above. Heater-cooler fluid of the heater-cooler device 10 is circulated through an intermediate heat exchanger of each of the heat transfer devices 303a and 303b to permit thermal exchange with an intermediate fluid to be pumped to a perfusion system heat exchanger (not shown in FIG. 8). The heat transfer device 303a may be used to provide an intermediate heat exchanger for an oxygenation line. The heat transfer device 303b may be used to provide an intermediate heat exchanger for a cardioplegia line. Each heat transfer device 303 can be removed and replaced individually. As the heater-cooler fluid is fluidically isolated from the intermediate passage of each heat transfer device 303, the need to disinfect the entire heater-cooler device 10 is reduced, and practically eliminated, if a fluid with antiseptic properties is used as heater-cooler fluid.

[0187] The diagram in FIG. 9 shows an exemplary sequence of method steps of a control method 50 for controlling the temperature of a treatment device using a heater-cooler apparatus. The method comprises a step 52 of providing a heater-cooler device of a heater-cooler apparatus for controlling the temperature of an extracorporeal fluid passing through the treatment device. In step 54, an intermediate heat exchanger with an intermediate passage is provided between the heater-cooler device and the treatment device. The intermediate passage fluidically isolates the heater-cooler transfer fluid from the treatment device. In step 56, a heater-cooler fluid is provided in the heater-cooler device. The heater-cooler fluid may be an antiseptic fluid. Further, an intermediate fluid is provided in the intermediate passage. The intermediate fluid may be a different fluid than the heater-cooler fluid. For instance, the intermediate fluid may be a fluid chosen for its properties reducing wear of the coils in the heat exchanger of the treatment device. The intermediate fluid may be water.

[0188] In step 58, the heater-cooler fluid is circulated through the intermediate heat exchanger to permit thermal exchange with the intermediate fluid. The heat exchange mechanism may comprise a disposable heat exchanger as part of a disposable intermediate passage. The heat exchange mechanism may comprise a disposable heat exchanger component as part of a disposable intermediate passage. In step 60, the intermediate fluid is used to control the temperature of the treatment device.

[0189] In optional step 62, the temperature or the flow rate, or both the temperature and the flow rate, of one or more of the heater-cooler fluid, the intermediate fluid, and/or the treatment fluid are measured. The temperature and/or flow rate can be used to better control the heat transfer, and thus the temperature of the treatment fluid leaving the treatment device. In optional step 64, the flow rate of the heater-cooler fluid, of the intermediate fluid, or the flow rates of both the heater-cooler fluid and the intermediate fluid are controlled to better modulate the heat transfer at the treatment device. The control may comprise a closed-loop control mechanism with a set point temperature or heat transfer gradient.

[0190] FIG. 10 shows a diagram setting out an exemplary sequence of method steps of a method 70 of controlling thermal transfer in a perfusion system heat exchanger. The method comprises a step 72 of providing a perfusion system heat exchanger. The perfusion system heat exchanger is part of an extracorporeal fluid treatment device for conditioning an extracorporeal patient fluid for administration to a patient. The perfusion system heat exchanger comprises a first fluid passage for a liquid heat transfer medium and a second fluid passage for the extracorporeal patient fluid to be temperature-controlled via exchange of thermal energy with the heat transfer medium.

[0191] In step 74, a heat transfer medium is provided through the first fluid passage of the perfusion system heat exchanger. The heat transfer medium comprises antimicrobial fluid. In an optional step 76, the perfusion system heat exchanger may be provided as part of an oxygenator, and/or as part of a cardioplegia delivery system. Likewise (not shown in FIG. 10), the perfusion system heat exchanger may be provided as a ‘stand-alone’ unit, to control the temperature of an extracorporeal fluid in a fluid line. In an optional step 78, glycol is provided as heat transfer medium. In step 80, the heat transfer medium is used to control the thermal transfer in the perfusion system heat exchanger, ie by flowing the heat transfer medium through the first fluid passage and by flowing the extracorporeal patient fluid to be temperature-controlled through the second fluid passage.

[0192] The expressions heat transfer fluid and thermal transfer fluid may be considered synonymous for the purposes of the present specification.