The present disclosure relates to extracorporeal circulation. More specifically, the present disclosure relates to extracorporeal blood conditioning devices and methods for conditioning blood in extracorporeal circulation.
Generally, hollow fiber blood oxygenators that are used to exchange oxygen (O2) and carbon dioxide (CO2) in extracorporeal circulation during cardiac surgery have one of two forms. Either the oxygenator has a cylindrical housing with a crisscross hollow fiber mat spirally wound around a cylindrical central core, or the oxygenator has a polygonal housing with stacked (piled) hollow fiber mat layers. Blood flows outside the hollow fiber lumens and oxygenating gases flow inside the hollow fiber lumens.
In cylindrically wound oxygenators, blood flow across the hollow fibers may be radial, longitudinal, circumferential, or a combination of two or more of these. Often, this leads to a blood flow path that is relatively long and non-laminar to guarantee high gas exchange efficiency with reduced surface area and limited device priming volume, which are important parameters for optimal patient perfusion. If the blood path is too long, the resulting pre-oxygenator to post-oxygenator pressure gradient may be elevated, causing excessive mechanical stress and possible damage to blood cells. Also, at times, the pressure gradient may become so high that it is not possible to reach a desired extracorporeal blood flow rate, especially if the heart lung machine (HLM) pump, used to force blood through the extracorporeal circuit, is of the centrifugal (non-occlusive) type. Such situations may lead the perfusionist, i.e., the HLM specialist, to change out the oxygenator during operation, which is a traumatic event putting the patient at risk, as circulation needs to be momentarily interrupted. Moreover, from a manufacturing point of view, a wound oxygenator is potted with potting material (resin) at both extremities to hermetically seal and separate the blood from the gases. This potting is often done in two or more steps, which adds complexity and cost to manufacturing the oxygenator.
In stacked hollow fiber mat layer oxygenators, blood flows outside the hollow fibers in a direction that is transverse to the stacked hollow fiber mat layers. Typically, this leads to shorter blood flow paths than in the cylindrically wound oxygenator and the resulting pre-oxygenator to post-oxygenator blood pressure gradient is lower such that mechanical damage to blood cells is reduced. However, an inconvenience derives from the housing shape which is generally polygonal, requiring the potting to be polygonal and characterized by dead angles where blood can stagnate and start to clot. This may cause progressive loss of gas exchange efficiency and, sometimes, force the perfusionist to change out the oxygenator during operation, which is, as already explained, a traumatic event as circulation needs to be momentarily interrupted. Moreover, polygonal fiber potting is often performed in more than two steps, which adds complexity and cost to manufacturing the oxygenator.
For the above reasons, manufacturers continue to improve the oxygenator devices.
As recited in examples, Example 1 is a device for conditioning blood including a heat exchanger module including a heat exchanger fiber layer including heat exchanger fibers to receive a heat exchanger fluid and exchange heat with the blood, a gaseous micro-emboli removal module including a micro-porous fiber layer including micro-porous fibers to receive atmospheric or sub-atmospheric pressures such that at least some gaseous micro-emboli are drawn from the blood through the micro-porous fibers, a gas exchanger module including a gas exchanger fiber layer including gas exchanger fibers to receive a gas mixture and exchange gas with the blood, and a potting material body that embeds the heat exchanger fibers, the micro-porous fibers, and the gas exchanger fibers and defines a blood compartment that extends through the heat exchanger module, the gaseous micro-emboli removal module, and the gas exchanger module.
Example 2 is the device of Example 1, including a heat exchanger housing sealed to the potting material body and having an inlet and an outlet, wherein the heat exchanger housing provides a first chamber in fluid communication with the inlet and inner lumens of the heat exchanger fibers on one side of the heat exchanger fibers and a second chamber in fluid communication with the outlet and the inner lumens of the heat exchanger fibers on the opposite side of the heat exchanger fibers.
Example 3 is the device of Example 1, including a gaseous micro-emboli removal module housing sealed to the potting material body and having a fluid inlet in fluid communication with at least inner lumens of the micro-porous fibers on one side of the micro-porous fibers.
Example 4 is the device of Example 1, including a gas exchanger housing sealed to the potting material body and having a gas inlet and a gas outlet, wherein the gas exchanger housing provides a first chamber in fluid communication with the gas inlet and inner lumens of the gas exchanger fibers on one side of the gas exchanger fibers and a second chamber in fluid communication with the gas outlet and the inner lumens of the gas exchanger fibers on the opposite side of the gas exchanger fibers.
Example 5 is the device of Example 1, including a first spacer and a second spacer embedded in the potting material body, wherein the first spacer is situated between the heat exchanger module and the gaseous micro-emboli removal module and the second spacer is situated between the gaseous micro-emboli removal module and the gas exchanger module.
Example 6 is the device of Example 1, wherein at least one of: the heat exchanger module includes stacked heat exchanger hollow fiber mat layers, wherein the heat exchanger hollow fiber mat layers are alternatively orthogonally angled from one another, the gaseous micro-emboli removal module includes stacked micro-porous hollow fiber mat layers, wherein the micro-porous hollow fiber mat layers are alternatively orthogonally angled from one another, and the gas exchanger module includes stacked gas exchanger hollow fiber mat layers, wherein the gas exchanger hollow fiber mat layers are alternatively orthogonally angled from one another.
Example 7 is the device of Example 1, wherein the blood compartment is a cylindrical blood compartment and the blood flows longitudinally from one end of the cylindrical blood compartment to the other end of the cylindrical blood compartment.
Example 8 is the device of Example 1, including a blood inlet cap having a blood inlet port and a blood outlet cap having a blood outlet port, such that the blood flows in the blood inlet port and through the blood compartment to the blood outlet port.
Example 9 is the device of Example 1, including an arterial blood filter embedded in the potting material body and situated adjacent the gas exchanger module.
Example 10 is a device for conditioning blood including a blood inlet cap including a blood inlet, a blood outlet cap including a blood outlet, a gas exchanger module situated between the blood inlet cap and the blood outlet cap, a potting material body on each side of the gas exchanger module, a gas exchanger housing sealed to the potting material body and having a gas inlet and a gas outlet, and longitudinal separators that separate the gas exchanger housing into a first chamber in fluid communication with the gas inlet and inner lumens of the gas exchanger hollow fibers on one side of the gas exchanger hollow fibers and a second chamber in fluid communication with the gas outlet and the inner lumens of the gas exchanger hollow fibers on the opposite side of the gas exchanger hollow fibers. The gas exchanger module including stacked gas exchanger hollow fiber mat layers including gas exchanger hollow fibers configured to receive a gas mixture and exchange gas with the blood, where the gas exchanger hollow fiber mat layers are alternatively orthogonally angled from one another. The potting material body defining a blood compartment through the gas exchanger module, such that the blood flows outside the gas exchanger hollow fibers.
Example 11 is the device of Example 10, including at least one of a heat exchanger module including stacked heat exchanger hollow fiber mat layers including heat exchanger hollow fibers configured to receive a heat exchanger fluid to exchange heat with the blood, and a gaseous micro-emboli removal module including stacked micro-porous hollow fiber mat layers including micro-porous hollow fibers configured to receive atmospheric or sub-atmospheric pressures such that at least some gaseous micro-emboli are drawn from the blood through the micro-porous hollow fibers.
Example 12 is the device of Example 11, including at least one of a heat exchanger housing sealed to the potting material body and having an inlet and an outlet, wherein the heat exchanger housing provides a first chamber in fluid communication with the inlet and inner lumens of the heat exchanger hollow fibers on one side of the heat exchanger hollow fibers and a second chamber in fluid communication with the outlet and the inner lumens of the heat exchanger hollow fibers on the opposite side of the heat exchanger hollow fibers, and a gaseous micro-emboli removal module housing sealed to the potting material body and having a fluid inlet in fluid communication with at least inner lumens of the micro-porous hollow fibers on one side of the micro-porous hollow fibers.
Example 13 is the device of Example 10, including an arterial blood filter embedded in the potting material body and situated adjacent the gas exchanger module.
Example 14 is a method of manufacturing a device for conditioning blood. The method includes stacking gas exchanger hollow fiber mat layers in a potting mold, stacking micro-porous hollow fiber mat layers over the gas exchanger hollow fiber mat layers in the potting mold, stacking heat exchanger hollow fiber mat layers over the micro-porous hollow fiber mat layers in the potting mold, spinning the potting mold around a longitudinal axis of the potting mold, and introducing liquid potting material into the potting mold as the potting mold spins to embed the gas exchanger hollow fiber mat layers, the micro-porous hollow fiber mat layers and the heat exchanger hollow fiber mat layers in the potting material and create a blood compartment that extends through the gas exchanger hollow fiber mat layers, the micro-porous hollow fiber mat layers and the heat exchanger hollow fiber mat layers.
Example 15 is the method of Example 14, wherein introducing liquid potting material into the potting mold as the potting mold spins creates a cylindrical blood compartment defined by an inner diameter of the potting material.
Example 16 is the method of Example 15, including removing the potting mold, and cutting the potting material away to expose ends of heat exchanger hollow fibers in the heat exchanger hollow fiber mat layers, ends of micro-porous hollow fibers in the micro-porous hollow fiber mat layers and ends of gas exchanger hollow fibers in the gas exchanger hollow fiber mat layer.
Example 17 is the method of Example 16, including sealing a heat exchanger housing to the potting material and sealing a gaseous micro-emboli removal module housing to the potting material and sealing a gas exchanger housing to the potting material.
Example 18 is the method of Example 14, including placing a blood outlet cap support in the potting mold followed by placing an arterial blood filter screen layer in the potting mold and then stacking the gas exchanger hollow fiber mat layers into the potting mold prior to the spinning and the introducing steps.
Example 19 is the method of Example 14, including situating one or more of a first spacer between the gas exchanger hollow fiber mat layers and the micro-porous hollow fiber mat layers, a second spacer between the micro-porous hollow fiber mat layers and the heat exchanger hollow fiber mat layers, and a blood inlet cap support on the heat exchanger hollow fiber mat layers, prior to spinning the potting mold around the longitudinal axis of the potting mold and introducing the liquid potting material into the potting mold.
Example 20 is the method of Example 14, including one or more of: knitting a discontinuous weft of a single layer of gas exchanger hollow fibers and cutting the discontinuous weft where the single layer of gas exchanger hollow fibers is missing to provide a gas exchanger hollow fiber mat layer that is stacked into the potting mold; knitting a discontinuous weft of a single layer of micro-porous hollow fibers and cutting the discontinuous weft where the single layer of micro-porous hollow fibers is missing to provide a micro-porous hollow fiber mat layer that is stacked into the potting mold; and knitting a discontinuous weft of a single layer of heat exchanger hollow fibers and cutting the discontinuous weft where the single layer of heat exchanger hollow fibers is missing to provide a heat exchanger hollow fiber mat layer that is stacked into the potting mold.
While multiple embodiments are disclosed, still other embodiments of the present disclosure will become apparent to those skilled in the art from the following detailed description, which shows and describes illustrative embodiments of the disclosure. Accordingly, the drawings and detailed description are to be regarded as illustrative in nature and not restrictive.
While the disclosure is amenable to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and are described in detail below. The intention, however, is not to limit the disclosure to the embodiments described. On the contrary, the disclosure is intended to cover all modifications, equivalents, and alternatives falling within the scope of the disclosure as defined by the appended claims.
In other embodiments, the device 22 includes different functional components or modules. In some embodiments, the device 22 includes only an oxygenator 22c configured to exchange O2 and CO2 with the blood. In some embodiments, the device 22 includes only a heat exchanger 22a configured to exchange heat with the blood and an oxygenator 22c configured to exchange O2 and CO2 with the blood. In some embodiments, the device 22 includes only a GME removal module 22b configured to remove gaseous micro-emboli from the blood and an oxygenator 22c configured to exchange O2 and CO2 with the blood. In some embodiments, the system 20 includes other components, such as other heat exchangers, GME removers, and gas exchangers. In some embodiments, these components or modules are structurally integrated into the device 22. In other embodiments, these components or modules are exchangeable, such that various modules may be easily added or removed from the device 22.
The system 20 includes the device 22, a processing unit 24, and a blood reservoir 26. In embodiments, the processing unit 24 may be a heart lung machine (HLM) or part of an HLM, as used in cardiopulmonary bypass surgery. Also, embodiments of the subject matter described herein may be implemented within the context of any number of different processing units, blood reservoirs, heat exchangers, GME removers, and oxygenators.
The processing unit 24 includes components, such as pumps, one or more controller assemblies including computing devices, one or more peripheral display devices, and one or more user interfaces, for providing the functions of the system 20. The functions of the system 20 include receiving blood from a patient 28, providing the blood to the blood reservoir 26, and supplying the blood from the blood reservoir 26 to the blood conditioning device 22. After being conditioned in the device 22, the blood can be returned to the patient 28.
The processing unit 24 is operatively coupled to the patient 28 and to the extracorporeal blood circulation system. Blood is taken from the patient 28 by means of a venous blood tubing line 30 and received by the blood reservoir 26. Besides this, blood may be aspirated into the reservoir 26 by means of one or more suckers from the operating field and be otherwise received into the blood reservoir 26 from the patient 28. In embodiments, the blood reservoir 26 includes a filter for filtering the blood received from the patient 28 and the operating field, prior to passing the blood to the device 22.
The device 22 is fluidly coupled to the blood reservoir 26 to receive the blood from the blood reservoir 26. A roller, or centrifugal blood pump 32 that is controlled by processing unit 24 may be interposed between the blood reservoir 26 and the blood conditioning device 22. The pump 32 is fluidly coupled to the blood reservoir by blood tubing line 34 and fluidly coupled to the device 22 by blood tubing line 36. The pump 32 is used for pumping blood from the outlet port of the blood reservoir 26 through the blood tubing line 34 and to the inlet port of the device 22 through the blood tubing line 36.
The device 22 is coupled to a heater/cooler 38 that provides a fluid, such as water, at a controlled temperature to the heat exchanger 22a through inlet fluid tubing line 40 for heating/cooling the blood. The heater/cooler 38 receives returning fluid from the blood conditioning device 22 through the outlet fluid tubing line 42. In embodiments, the heater/cooler 38 is controlled by the processing unit 24.
The device 22 is further fluidly coupled to vacuum source 44 by fluid tubing line 46 for applying a vacuum through the fluid tubing line 46 to the GME removal module 22b. Alternatively, atmospheric pressure may be provided to the GME removal module 22b, such as by keeping the fluid tubing line 46 open to the atmosphere. In embodiments, the fluid tubing line 46 provides from atmospheric pressure to a vacuum of −400 mmHG to the GME removal module 22b for removing GME from the blood. In embodiments, the vacuum source 44 is controlled by the processing unit 24.
The device 22 is further fluidly coupled to a gas mixture module or gas blender 48 by inlet fluid tubing line 50. The gas blender 48 provides oxygenation gases to the oxygenator 22c through inlet fluid tubing line 50 to oxygenate the processed blood. The gas outlet 52 of the device 22 is kept fully open to the atmosphere, such that given the pressure losses in the oxygenator gas, oxygenation takes place, as usually happens with all existing oxygenators, with the oxygenation gases at pressure values slightly over or close to atmospheric pressure values. In embodiments, the gas blender 48 is controlled by the processing unit 24.
The device 22 receives the blood from the reservoir 26 through the blood tubing line 36 and processes the blood by exchanging heat with the blood in the heat exchanger 22a, removing GME from the blood in the GME removal module 22b, and oxygenating the blood in the oxygenator 22c. The device 22 returns the processed blood to the patient 28 through blood tubing line 54. In embodiments, the device 22 is operatively coupled to the processing unit 24, which controls the return of the temperature-controlled, degassed, and oxygenated blood to the patient 28 through the blood tubing line 54, such as an arterial line.
Generally, the device 100 includes a blood inlet cap 102, a heat exchanger module 104, a GME removal module 106, a gas exchanger or oxygenator module 108, and a blood outlet cap 110. Each of the modules, including the heat exchanger module 104, the GME removal module 106, and the gas exchanger module 108, includes a pile of stacked single hollow fiber mat layers that are alternatively stacked at 90° angles. That is, each of the hollow fiber mat layers includes a layer of hollow fibers that are parallel to one another and define the hollow fiber direction for that layer. These layers are alternatively stacked with 90° angle hollow fiber directions. Also, the characteristics of the hollow fiber mat layers in one module may be and often are different from the characteristics of the hollow fiber mat layers in the other modules.
The three modules are potted with a potting material (resin) in a single step to form a single potting material body 112 that defines a single, unified, cylindrical blood compartment 114 through the three modules. End portions of the hollow fibers of the hollow fiber mat layers are embedded in the potting material body 112 and the internal surface of the potting material body 112 circumscribes and defines the blood compartment 114. The blood compartment 114 provides a blood flow path through the three modules, where the blood flows on the outside of the hollow fibers of the hollow fiber mat layers of the three modules. This results in the device 100 having a cylindrical internal shape for the blood to flow through from the blood inlet cap 102 to the blood outlet cap 110.
Further, during manufacturing the ends of the hollow fibers of the hollow fiber mat layers of the three modules are embedded in the potting material that eventually becomes the potting material body 112. This leads to the potting material having an outside squared cross-section that is cut away on the external surfaces to expose the inner lumens of the hollow fibers of the hollow fiber mat layers and provide access to the inner lumens of the hollow fibers from outside the potting material body 112. Each of the three modules is further fitted with an external housing that includes one or more connectors to provide appropriate fluids/gases to the device.
Thus, device 100 includes stacked hollow fiber mat layers such that the blood flows outside the hollow fibers from the blood inlet cap 102 to the blood outlet cap 110 in a direction that is transverse to the stacked hollow fiber mat layers. This results in a shorter blood flow path than in a cylindrically wound blood conditioner and the resulting pressure gradient is lower, which reduces or prevents mechanical damage to blood cells. Also, the blood compartment 114 is cylindrical such that the blood flow path does not include dead angles where blood can stagnate and start to clot. In addition, the potting material (resin) is applied to all three modules in one step to provide a single, unified, blood compartment 114, which reduces the complexity and cost of manufacturing the device 100.
As illustrated in
The blood enters the device 100 through the blood inlet port 118 as shown by arrow 170a and flows in a circular motion around the blood inlet cap 102 and into the cylindrical blood compartment 114. In embodiments, as illustrated, the blood flows through the blood inlet port 118 of the blood inlet cap 102 and then through the heat exchanger module 104, the GME removal module 106, and the gas exchanger module 108 before exiting the device 100 through the blood outlet port 122 of the blood outlet cap 110 as shown by arrow 170b.
The first module in the cascade of three modules to be crossed by the blood is the heat exchanger module 104. The heat exchanger module 104 includes heat exchanger hollow fibers in stacked heat exchanger hollow fiber mat layers 124. The heat exchanger hollow fibers at 124 are configured to receive a heat exchanger fluid, such as water, for exchanging heat with the blood.
The heat exchanger module 104 includes a heat exchanger housing 126 that is external to the potting material body 112 and that includes a fluid inlet port 128 and a fluid outlet port 130. The heat exchanger housing 126 is sealed to the potting material body 112 to prevent heat exchanger fluid from leaking out and divided into two inner chambers, an inlet fluid chamber 132 and an outlet fluid chamber 134. The heat exchanger housing 126 is divided into the two inner chambers, by two diametrically opposed longitudinal spacers 136 and 138 (shown in
Also, in embodiments, the device 100 includes blood inlet cap supports 140 embedded in the potting material body 112 and extending above the heat exchanger hollow fiber mat layers 124. The blood inlet cap 102 is attached to and supported by the blood inlet cap supports 140. In embodiments, the device 100 includes an inlet cap spacer 142 situated on the heat exchanger hollow fiber mat layers 124 and embedded in the potting material body 112. In embodiments, the device 100 includes the blood inlet cap supports 140 attached to or on the inlet cap spacer 142.
In addition, in embodiments, the device 100 includes a module spacer 144 between the heat exchanger module 104 and the GME removal module 106. The module spacer 144 is embedded into the potting material body 112. In embodiments, the module spacer 144 is made of plastic.
The second module in the cascade of three modules to be crossed by the blood is the GME removal module 106. The GME removal module 106 includes micro-porous hollow fibers in stacked micro-porous hollow fiber mat layers 146. The GME micro-porous hollow fibers at 146 are different from the heat exchanger hollow fibers at 124, in that the micro-porous hollow fibers at 146 are permeable to gas and impermeable to liquids, while the heat exchanger hollow fibers at 124 are permeable only to energy or heat. Also, the heat exchanger hollow fiber mats 124 and the micro-porous hollow fiber mats 146 may differ in fiber linear density, dimensions, and number of warp yarns.
In the GME removal module 106, atmospheric pressure or sub-atmospheric pressure (a vacuum) is applied to the inner lumens of the micro-porous hollow fibers at 146 to pull GME from the blood through the walls of the micro-porous hollow fibers at 146. This removes the GME form the blood, where the GME needs to be removed from the blood before returning the blood to the patient in order to avoid embolization.
The GME removal module 106 includes a GME removal module housing 148 that includes a fluid outlet 150 in fluid communication with at least one side of the micro-porous hollow fibers at 146. The GME removal module housing 148 is sealed to the potting material body 112 and provides atmospheric or sub-atmospheric pressures received at the fluid outlet 150 to the micro-porous hollow fibers at 146. In embodiments, the fluid outlet 150 is in fluid communication with an inner chamber 149 that is in fluid communication with all sides of the micro-porous hollow fibers at 146.
The third module in the cascade of three modules to be crossed by the blood is the gas exchanger or oxygenator module 108. In embodiments, the device 100 includes a module spacer 152 situated between the GME removal module 106 and the gas exchanger module 108.
The module spacer 152 includes, on the GME removal module 106 side, a filter screen 116 whose function is to retain gaseous micro-emboli in the GME removal module 106 to facilitate their removal. The module spacer 152 and the filter screen 116 are embedded into the potting material body 112. In embodiments, the module spacer 152 and/or the filter screen 116 are made of plastic.
The gas exchanger module 108 includes gas exchanger hollow fibers in stacked gas exchanger hollow fiber mat layers 154. The gas exchanger hollow fibers at 154 are configured to receive a gas mixture and exchange gas with the blood. The gas exchanger hollow fibers at 154 are different from the heat exchanger hollow fibers at 124, in that the gas exchanger hollow fibers at 154 are permeable to gas and impermeable to liquids, while the heat exchanger hollow fibers at 124 are permeable only to energy or heat. Also, the heat exchanger hollow fiber mat layers 124, the micro-porous hollow fiber mat layers 146, and the gas exchanger hollow fiber mat layers 154 may each differ in fiber linear density, dimensions, and number of warp yarns.
The gas exchanger module 108 includes a gas exchanger housing 156 that includes opposed gas exchanger fluid connectors, a gas inlet port 158 and a gas outlet port 160. The gas exchanger housing 156 is sealed to the potting material body 112 to prevent the gas mixture from leaking out. The gas exchanger housing 156 is divided into two inner chambers, an inlet gas chamber 162 and an outlet gas chamber 164, by the two diametrically opposed longitudinal spacers 136A and 138A (shown in
In embodiments, the device 100 includes one or more blood outlet cap supports 166 embedded in the potting material body 112. Also, in embodiments, the device 100 includes an arterial blood filter 168 situated under the gas exchanger module 108 and between the gas exchanger module 108 and the blood outlet cap 110. The arterial blood filter 168 is obtained with one or more screen layers of suitable size, such as 20 to 40 microns, and embedded in the potting material body 112. In operation, the blood flows through the gas exchanger module 108 and the arterial blood filter 168 into the blood outlet cap 110 and out of the device 100 through the blood outlet port 122.
In other embodiments, the device 100 may include only one or two of: the heat exchanger module 104; the GME removal module 106; and the gas exchanger module 108. These different embodiments may be used in different applications. In some embodiments, such as extracorporeal membrane oxygenation (ECMO) or extracorporeal life support (ECLS), the heat exchanger module 106 may not be needed. In some embodiments, such as for cardiac surgery, the device 100 can include at least the heat exchanger module 104 and the oxygenator module 108. In some embodiments, the GME removal module 106 is included for extra safety by eliminating or reducing the GME in the blood.
The flow of heat exchanger fluid, such as water, and gas exchanger fluid, such as oxygen, through the hollow fiber mat layers is shown by arrows in
The hollow fiber mat layer 200 is obtained by knitting a mat or weave that has a discontinued weft and cutting the weave into pieces at spaces 202 where the weft is missing. The hollow fiber mat layer 200 includes hollow fibers 204 as the weft and yarn 206 as the warp. A single layer of hollow fibers 204 is knitted into a rectangle having the height H of the hollow fibers 204 and the width W. The weft is discontinued, such that the spaces 202 having width 2S are left between the hollow fiber mat layer 200 and other mat layers that may be knit on each side of the hollow fiber mat layer 200. The yarn 206 is cut at 208 in the middle of the spaces 202 (1S from the hollow fiber mat layer 200) on each side of the hollow fiber mat layer 200 to remove the hollow fiber mat layer 200. In embodiments, an adhesive layer 210 having a width WA is attached to the top and to the bottom of the hollow fibers 204. In embodiments, hollow fiber mat layers may be knit with different materials, have different fiber dimensions, have different linear density, and have a different number of warp yarns for each of the modules.
In embodiments, the components of the device 100 are piled into the potting mold 220 in the following order. First, the blood outlet cap supports 166 (shown in
With all of these components loaded into the potting mold 220, potting is done in one step by spinning the potting mold 220 around the vertical axis Z at a certain speed and introducing the liquid potting material (resin) into the potting mold 220. The liquid potting material spreads to the outside of the potting mold 220 due to centrifugal forces and embeds the components of the device 100 in the potting material. At the end of the potting phase, the central portion of the potting material pack, which is the cylindrical blood compartment 114, is an open space occupied by the stacked horizontal hollow fiber mat layers of the modules and circumscribed by the inner surface 222 of the potting material body 112. The outer surface of the potting material has the same shape of the potting mold 220, that can be removed after resin curing, resulting in a potted body of the device 100. In embodiments, the potting mold 220 includes silicon rubber.
The diameter D (shown in
After removing the potting mold 220, the potted body 230 is ready for being cut to form the outside of the potting material body 112. In this phase of the construction, access to the inner lumens of the hollow fibers is obtained by removing the potting material (resin) that covers the ends of the hollow fibers. As illustrated, a thin slice E of the potting material is removed from each outer side of the potted body 230, where E must be large enough for exposing the ends of the hollow fibers on all sides of the potted body 230. This results in the cross-section of the cut potted body 230 being inscribed in a square having a side C=W+2T=H−2E, where T is the potting material minimum thickness.
The same or a similar construction is repeated for the heat exchanger module 104 and the GME removal module 106, where the GME removal module housing 148 has only one fluid outlet 150 and one corresponding inner chamber 149. In embodiments, the opposed longitudinal spacers 136A and 138A are made of rubber.
In assembly of the device 100, the heat exchanger housing 126, GME removal module housing 148, and gas exchanger housing 156 are attached to the cut potted body 230, which is now the potting material body 112. The blood inlet cap 102 is attached to the blood inlet cap supports 140 and sealed adjacent the inlet cap spacer 142, which is situated on the heat exchanger hollow fiber mat layers 124 and embedded in the potting material body 112. The blood inlet cap 102 is shaped to impart a spiral flow direction to the entering blood, see
The blood outlet cap 110 is attached to the blood outlet cap supports 166 that are embedded in the potting material body 112. The blood outlet cap 110 is sealed adjacent the arterial blood filter 168 situated under the gas exchanger module 108 and between the gas exchanger module 108 and the blood outlet cap 110.
In embodiments, laser welding can be used to seal one or more of the blood inlet cap 102, the blood outlet cap 110, the heat exchanger housing 126, the GME removal module housing 148, and the gas exchanger housing 156 to the underlying potting material body 112 to form the device 100.
The device 300 includes a blood inlet cap 302, a blood inlet cap spacer 304, a cut potted body 306, an arterial blood filter 308, a gas exchanger housing 310, and a blood outlet cap 312. The blood enters the blood inlet cap 302 and flows through the blood inlet cap spacer 304, the cut potted body 306, and the arterial blood filter 308, before exiting through the blood outlet cap 312.
The blood inlet cap 302 includes a blood inlet port 314 through which blood enters the device 300 and a purging line port 316 through which air can be purged from the device 300. In embodiments, as illustrated in
In embodiments as illustrated in
The cut potted body 306 includes gas exchanger hollow fiber mat layers 320 situated in a cylindrical blood compartment 322. The cut potted body 306 is like the cut potted body 230 in that it has been constructed using the construction techniques used to construct the cut potted body 230. The sides of the cut potted body 306 include exposed inner lumens of the gas exchanger hollow fibers at 324 in the gas exchanger hollow fiber mat layers 320.
The gas exchanger housing 310 includes opposed gas exchanger fluid connectors, a gas inlet port 326 and a gas outlet port 328. The gas exchanger housing 310 is sealed to the cut potted body 306 to prevent gas from leaking out. The gas exchanger housing 310 is divided into an inlet gas chamber and an outlet gas chamber by diametrically opposed longitudinal spacers 330 and 332 that are inserted in diametrically opposed corners of the gas exchanger housing 310. These longitudinal spacers 330 and 332 are like the longitudinal spacers 136A and 138A (shown in
The inlet gas chamber puts the gas inlet port 326 in fluid communication with one side of the inner lumens of the gas exchanger hollow fibers at 324. The outlet gas chamber puts the gas outlet port 328 in fluid communication with the opposite side of the inner lumens of the gas exchanger hollow fibers. In this way, gas flows from the gas inlet port 326 through the inner lumens of the gas exchanger hollow fibers and exits the device 300 through the gas outlet port 328.
In embodiments as illustrated in
The arterial blood filter 308 includes blood outlet cap supports 334 that are attached to a corresponding ring 336 on the blood outlet cap 312. The ring 336 on the blood outlet cap 312 is sealed, such as by adhesives or laser welding, to the blood outlet cap supports 334 to prevent leakage of the blood. The gas exchanger housing 310 is further attached and sealed to the blood inlet cap 302 and to the blood outlet cap 312.
In operation, a gas mixture is provided to the gas inlet port 326 to flow through the inner lumens of the gas exchanger hollow fiber mat layers 320 and out the gas outlet port 328. The blood enters the device 300 through the blood inlet port 314 and flows in a circular motion around the blood inlet cap 302 and through the blood inlet cap spacer 304 and into the cylindrical blood compartment 322 of the potted body 306. Next, the blood flows through the hollow fiber mat layers 320 and then through the arterial blood filter 308 and into the blood outlet cap 312. The blood exits the device 300 through the blood outlet port 338 of the blood outlet cap 312.
In operation, a gas mixture is provided to the gas inlet port 326 for flowing though the gas exchanger hollow fiber mats 320 and the blood is provided at the blood inlet port 314 to flow through the device 300 before exiting through the blood outlet port 338 of the blood outlet cap 312.
In operation, a gas mixture is provided to the gas inlet port 414 for flowing though the gas exchanger hollow fiber mats and the blood is provided at the blood inlet port 404 to flow through the device 400 before exiting through the blood outlet port 410 of the blood outlet cap 408.
At 500, the method includes stacking gas exchanger hollow fiber mat layers into a potting mold. In embodiments, the method further includes one or more of placing a blood outlet cap support in the potting mold and placing an arterial blood filter in the potting mold and then stacking the gas exchanger hollow fiber mat layers into the potting mold.
At 502, the method includes stacking micro-porous hollow fiber mat layers over the gas exchanger hollow fiber mat layers in the potting mold. In embodiments, the method includes situating a first spacer between the gas exchanger hollow fiber mat layers and the micro-porous hollow fiber mat layers.
At 504 the method includes stacking heat exchanger hollow fiber mat layers over the micro-porous hollow fiber mat layers in the potting mold. In embodiments, the method includes situating a second spacer between the micro-porous hollow fiber mat layers and the heat exchanger hollow fiber mat layers and/or a blood inlet cap support on the heat exchanger hollow fiber mat layers, prior to spinning the potting mold around the longitudinal axis of the potting mold and introducing liquid potting material into the potting mold.
At 506, the method includes spinning the potting mold around a longitudinal axis of the potting mold, and at 508, the method includes introducing liquid potting material into the potting mold as the potting mold spins to embed the gas exchanger hollow fiber mat layers and the micro-porous hollow fiber mat layers and the heat exchanger hollow fiber mat layers in the potting material and create a blood compartment that extends through the gas exchanger hollow fiber mat layers and the micro-porous hollow fiber mat layers and the heat exchanger hollow fiber mat layers. Where, in embodiments, introducing the liquid potting material into the potting mold as the potting mold spins creates a cylindrical blood compartment defined by an inner diameter of the potting material.
At 510, after potting material curing, the method includes removing the potting mold and cutting the potting material away to expose inner lumen ends of heat exchanger hollow fibers in the heat exchanger hollow fiber mat layers and inner lumen ends of micro-porous hollow fibers in the micro-porous hollow fiber mat layers and inner lumen ends of gas exchanger hollow fibers in the gas exchanger hollow fiber mat layer.
At 512, the method includes sealing one or more of a heat exchanger housing to the potting material, a gaseous micro-emboli module housing to the potting material, and a gas exchanger housing to the potting material. Also, in embodiments, the method further includes attaching a blood inlet cap and attaching a blood outlet cap.
In embodiments, the method can further include creating one or more of knitting a discontinuous weft of a single layer of gas exchanger hollow fibers and cutting the discontinuous weft where the single layer of gas exchanger hollow fibers is missing to provide a gas exchanger hollow fiber mat layer that is stacked into the potting mold; knitting a discontinuous weft of a single layer of micro-porous hollow fibers and cutting the discontinuous weft where the single layer of micro-porous hollow fibers is missing to provide a micro-porous hollow fiber mat layer that is stacked into the potting mold; and knitting a discontinuous weft of a single layer of heat exchanger hollow fibers and cutting the discontinuous weft where the single layer of heat exchanger hollow fibers is missing to provide a heat exchanger hollow fiber mat layer that is stacked into the potting mold.
Various modifications and additions can be made to the exemplary embodiments discussed without departing from the scope of the present disclosure. For example, while the embodiments described above refer to particular features, the scope of this disclosure also includes embodiments having different combinations of features and embodiments that do not include all of the described features. Accordingly, the scope of the present disclosure is intended to embrace all such alternatives, modifications, and variations as fall within the scope of the claims, together with all equivalents thereof.
This application is a continuation of International Application No. PCT/IB2020/052855, filed Mar. 26, 2020, the disclosure of which is incorporated herein by reference.
Number | Date | Country | |
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Parent | PCT/IB2020/052855 | Mar 2020 | US |
Child | 17903347 | US |