Extracorporeal oxygenator with integrated air removal system

Abstract

To provide extracorporeal heat exchange and oxygenation devices which can be used for on-pump open-heart surgery to facilitate surgical procedures such as coronary artery bypass surgery.SOLUTION: An oxygenator apparatus 220 comprises a gas exchange unit 228, a heat exchange unit 226, and an integrated ventilation structure disposed in front of the heat exchange unit. The integrated ventilation structure includes one or more porous hollow fibers 232.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] [CROSS-REFERENCE TO RELATED APPLICATIONS] This application claims the benefit of U.S. Provisional Application No. 62 / 572,754, filed October 16, 2017. The disclosure of the prior application is considered part of (and is incorporated by reference into) the disclosure of this application.

[0002] This application relates to devices used during surgical procedures for the treatment of cardiac disease. For example, this application relates to extracorporeal heat exchange and oxygenation devices that can be used for on-pump open heart surgery to facilitate surgical procedures such as coronary artery bypass surgery. Some of the extracorporeal heat exchange and oxygenation devices described in this application include an integrated air removal structure. [Background technology]

[0003] Hollow fiber oxygenators are utilized in extracorporeal circuits to meet the gas exchange needs of patients during cardiopulmonary bypass surgery. Blood from the patient is either gravity drained or vacuum assisted venous drainage (VAVD) is used to obtain the flow rate necessary to maintain sufficient volume in the reservoir. A pump (e.g., a peristaltic or centrifugal pump coupled to a magnetic drive) is used in the main line of the circuit to pump blood from the reservoir, through the oxygenator, and finally back to the patient.

[0004] Prior to initiation of bypass, a crystalloid priming solution is pumped through the extracorporeal circuit to remove air from the circuit components. In some cases, it may be difficult to remove significant amounts of air in the oxygenator during the priming process. Summary of the Invention

[0005] This application describes devices for use during surgical procedures for the treatment of cardiac disease. For example, this application describes an extracorporeal heat exchange and oxygenation device that can be used for on-pump open heart surgery to facilitate surgical procedures such as coronary artery bypass surgery. The extracorporeal heat exchange and oxygenation device described herein can include an integrated air removal structure.

[0006] In accordance with one aspect, the present disclosure is directed to a blood oxygenator including a blood inlet and a blood outlet. A blood flow path extends from the blood inlet to the blood outlet. The blood oxygenator also includes a gas exchange section disposed along the blood flow path, a heat exchange section disposed along the blood flow path prior to the gas exchange section, and one or more porous hollow fibers disposed along the blood flow path prior to the heat exchange section.

[0007] Such a blood oxygenator may include any one or more of the following features: An interior of the one or more porous hollow fibers may be in communication with an environmental space within or around the blood oxygenator. An interior of the one or more porous hollow fibers may be in communication with a vacuum source. The blood oxygenator may also include a flow distribution element disposed along the blood flow path prior to the one or more porous hollow fibers. In some embodiments, the one or more porous hollow fibers are wrapped around the flow distribution element. The one or more porous hollow fibers may be wrapped around the flow distribution element in a crossing helical pattern. The one or more porous hollow fibers may be disposed around the flow distribution element in a non-crossing helical pattern. The pores of the one or more porous hollow fibers allow air to enter the interior of the one or more porous hollow fibers while preventing liquid from entering the interior of the one or more porous hollow fibers.

[0008] In another aspect, the present disclosure is directed to a blood oxygenator including: (i) a housing defining a blood inlet and a blood outlet; (ii) a heat exchanger disposed within the housing and defining an interior space; (iii) a membrane oxygenator disposed within the housing and concentrically disposed around the heat exchanger; and (iv) one or more porous hollow fibers disposed in the interior space.

[0009] Such a blood oxygenator may include any one or more of the following features: The blood oxygenator may also include a flow distribution element disposed within the interior space. The one or more porous hollow fibers may be wrapped around the flow distribution element. The flow distribution element may be configured to promote a substantially uniform radial flow distribution of blood entering the heat exchanger. An interior of the one or more porous hollow fibers may be in communication with an environmental space within or around the blood oxygenator. An interior of the one or more porous hollow fibers may be in communication with a vacuum source. The one or more porous hollow fibers may be arranged in a crossing pattern. The one or more porous hollow fibers may be arranged in a non-crossing pattern.

[0010] In accordance with another aspect, the disclosure is directed to a method of constructing a blood oxygenator, the method including disposing a membrane oxygenator in a housing defining (i) a blood inlet, (ii) a blood outlet, and (iii) a blood flow path extending from the blood inlet to the blood outlet, disposing a heat exchanger along the blood flow path prior to the membrane oxygenator, and disposing one or more porous hollow fibers along the blood flow path prior to the heat exchanger.

[0011] Such methods may include any one or more of the following features: The one or more porous hollow fibers may be positioned such that an interior of the one or more porous hollow fibers communicates with an environmental space within or around the blood oxygenator. The method may also include configuring the oxygenator for connecting the one or more porous hollow fibers to a vacuum source. The method may also include positioning a flow distribution element along the blood flow path prior to the one or more porous hollow fibers. The one or more porous hollow fibers may be wrapped around the flow distribution element. The one or more porous hollow fibers may be wrapped around the flow distribution element in an intersecting helical pattern. At least some of the intersecting porous hollow fibers may be fluidly connected to one another by contact between each other. The one or more porous hollow fibers may be positioned around the flow distribution element in a non-intersecting helical pattern. The pores of the one or more porous hollow fibers allow air to enter the interior of the one or more porous hollow fibers while preventing liquid from entering the interior of the one or more porous hollow fibers.

[0012] Certain embodiments of the subject matter described herein may be implemented to achieve one or more of the following advantages: In some embodiments, using the devices and methods provided herein, a patient may undergo open heart surgery with less potential adverse effects. For example, using some embodiments described herein, a patient may be less exposed to the possibility of receiving an air embolism from the extracorporeal circuit. Thus, the risk of oxygen deprivation (e.g., stroke and other types of tissue ischemia) may be reduced. Additionally, in some instances, the clinician may be able to reduce the amount of time spent priming the circuit to ensure sufficient removal of air within the extracorporeal circuit. Thus, a relatively low-cost surgical procedure may be possible and the risk of clinician error may be reduced. Furthermore, using some embodiments described herein, a simplified extracorporeal circuit may be used compared to conventional extracorporeal circuits that use additional air removal devices. Furthermore, the air removal structures described herein facilitate the use of low-cost oxygen delivery devices. Such low-cost devices may result in less dilution of the patient's blood compared to conventional extracorporeal circuits. Less hemodilution reduces the chances that the patient's hematocrit will fall below a critical value, and thus the patient may require less blood transfusions.

[0013] Unless otherwise defined, technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art. Although methods and materials similar or equivalent to those described herein can be used to practice the invention, suitable methods and materials are described herein. All literature, patent applications, patents and other references mentioned herein are incorporated by reference in their entirety. In case of conflict, the present specification, including definitions, will control. In addition, the materials, methods, and examples are merely illustrative and are not intended to be limiting.

[0014] The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description herein. Other features, objects, and advantages will be apparent from the description and drawings, and from the claims. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 is a schematic diagram of a patient undergoing open heart surgery while being assisted with an extracorporeal circuit, according to certain embodiments described herein. [Diagram 2] FIG. 2 is a schematic diagram of an extracorporeal oxygenator (and integrated heat exchanger) according to certain embodiments described herein. [Diagram 3] FIG. 3 is a schematic diagram illustrating the priming process of the extracorporeal oxygenator of FIG. [Figure 4] FIG. 4 is a schematic diagram of an extracorporeal oxygenator (and integrated heat exchanger) including an integrated air removal structure according to some embodiments described herein. [Diagram 5] FIG. 5 is a schematic diagram illustrating the priming process of the extracorporeal oxygenator of FIG. [Figure 6] FIG. 6 is an exploded cross-sectional perspective view of the extracorporeal oxygenator (and integrated heat exchanger). [Figure 7] FIG. 7 is an exploded cross-sectional perspective view of an extracorporeal oxygenator (and integrated heat exchanger) including an integrated air removal structure according to some embodiments described herein. [Figure 8] FIG. 8 is a photograph of the end of an extracorporeal oxygenator (and integrated heat exchanger) including an integrated air removal structure according to some embodiments described herein. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Like numbers refer to corresponding parts throughout.

[0017] This application describes devices used during surgical procedures for the treatment of cardiac disease. For example, this application describes extracorporeal heat exchange and oxygenation devices that can be used for on-pump open heart surgery to facilitate surgical procedures such as coronary artery bypass surgery. Some of the extracorporeal heat exchange and oxygenation devices described herein may include an integrated air removal structure.

[0018] 1, a patient 10 may be treated using an exemplary extracorporeal blood flow circuit 100. In this illustrative example, the patient 10 is undergoing cardiac bypass surgery using the extracorporeal blood flow circuit 100. The circuit 100 is connected to the patient 10 at the patient's heart 12. Blood from the patient 10 is drawn from the patient 10 at the patient's heart 12, the blood circulates through the circuit 100, and then the blood is returned to the patient's heart 12.

[0019] The exemplary extracorporeal blood flow circuit 100 includes at least a venous tubing 110, a blood reservoir 120, a pump 130, an oxygenator 140, an arterial filter 150, and an arterial tubing 160. The venous tubing 110 is in physical contact with the heart 12 and is in fluid communication with the venous side of the circulatory system of the patient 10. The venous tubing 110 is also in fluid communication with an inlet of the reservoir 120. An outlet from the reservoir 120 is connected by tubing to an inlet of the pump 130. An outlet of the pump 130 is connected by tubing to an inlet of the oxygenator 140. An outlet of the oxygenator 140 is connected by tubing to an inlet of the arterial filter 150. An outlet of the arterial filter 150 (optional) is connected to an arterial tubing 160. The arterial tubing 160 is in physical contact with the heart 12 and is in fluid communication with the arterial side of the circulatory system of the patient 10.

[0020] Briefly, the extracorporeal blood flow circuit 100 operates by drawing venous blood from the patient 10 via venous tubing 110. The blood from venous tubing 110 is stored in a reservoir 120. At least some amount of blood is intended to be maintained in the reservoir 120 at all times during a medical procedure. The blood in the reservoir 120 is drawn from the reservoir 120 by a pump 130. Pressure created by the pump 130 forces the blood through an oxygenator 140. In the oxygenator 140, the venous blood is enriched with oxygen. Additionally, the temperature of the blood may be selectively increased or decreased using a heat exchanger incorporated in the oxygenator 140. The oxygen-enriched arterial blood leaves the oxygenator 140, travels through an arterial filter 150, and is infused into the patient's heart 12 by an arterial tubing 160.

[0021] Those skilled in the art will recognize that prior to use, the extracorporeal blood flow circuit 100 initially contains air which must be removed before the circuit 100 can be connected to the patient 10. To remove any air within the circuit 100, a priming fluid is introduced into the circuit 100. This process is referred to as priming the circuit 100.

[0022] An example of an oxygenator 200 with an integrated heat exchanger (or simply "oxygenator 200") is shown generally in Figure 2. Oxygenator 200 includes a housing 202. Housing 202 defines an inlet 203i and an outlet 203o. A blood flow path extends from inlet 203i to outlet 203o.

[0023] The heat exchanger 206 is disposed along the blood flow path. When blood (or priming fluid) enters the housing 202 through the inlet 203i, the blood typically flows radially toward the heat exchanger 206 and continuously flows radially into the heat exchanger 206. Temperature-controlled water also passes through the heat exchanger 206 from the inlet 207i to the outlet 207o (or in the reverse direction). While the heat exchanger 206 allows for heat exchange between the temperature-controlled water and the blood, the walls of the heat exchanger 206 physically separate the temperature-controlled water from the blood (to prevent mixing), in a manner typical of heat exchangers. The heat exchanger 206 can be constructed of metal or polymeric materials. In some embodiments, the heat exchanger 206 is constructed of multiple thin tubes. An interior space 204 is defined by the heat exchanger 206. The incoming blood flows through the interior space 204 before reaching the heat exchanger 206.

[0024] In some embodiments, a flow distribution element 205 is disposed in the interior space 204. The flow distribution element 205 is configured to promote a substantially uniform radial flow distribution of blood as it enters the interior space 204 and transitions to enter the heat exchanger 206.

[0025] An oxygen supply 208 (also referred to as a "gas exchanger") is disposed inside the housing 202 after the heat exchanger 206 along the blood flow path. In some embodiments, the oxygen supply 208 is disposed concentrically around the heat exchanger 206 such that blood flowing radially through the heat exchanger 206 can flow radially through the oxygen supply 208 in succession. Gas is also passed through the oxygen supply 208 from an inlet 209i to an outlet 209o. The oxygen supply 208 can be comprised of hollow fibers (membranes) that allow gas transfer between the gas and blood (e.g., oxygen and carbon dioxide exchange) while preventing mixing of the gas and blood.

[0026] In some embodiments, the ends of the individual tubular elements of the heat exchanger 206 and / or oxygen supply 208 are physically bonded together using a filler 210. The filler 210 may be urethane in some examples. After the filler 210 (in a flowable state) is applied to the ends of the individual tubular elements of the heat exchanger 206 and / or oxygen supply 208, the filler 210 is allowed to solidify. In a solid state, the filler 210 is trimmed (wrapping the ends of the individual tubular elements of the heat exchanger 206 and / or oxygen supply 208) so that openings to the interior of the individual tubular elements of the heat exchanger 206 and / or oxygen supply 208 are exposed. The openings allow temperature-controlled water to flow inside the tubular elements of the heat exchanger 206 and allow gas to flow inside the tubular elements of the oxygen supply 208.

[0027] After the blood flows through the oxygen supply 208 (and optional filtration media in some embodiments), it continues to flow radially outward until it hits a wall of the housing 202. The blood then exits through the outlet 203o. A removal port 211 may also be included. The removal port 211 may be used, for example, to allow air to exit the housing 202 while liquid (e.g., priming fluid or blood) is entering the housing 202. The removal port 211 may then be closed.

[0028] 3 illustrates the priming process of oxygenator 200. Prime fluid is pumped into housing 202 through inlet 203i. The prime fluid enters interior space 204 where it may impinge on flow distribution element 205. The prime fluid then flows in a generally radial direction into heat exchanger 206. From heat exchanger 206, the prime fluid flows in a generally radial direction into oxygen supply 208. After passing through oxygen supply 208, the prime fluid fills the remainder of the space within housing 202 before exiting oxygenator 200 through outlet 203o.

[0029] As the priming fluid flows in the manner described above, air within the housing 202 is displaced with the priming fluid. At least some of the displaced air is permitted to exit the housing via the removal port 211. Once priming fluid begins to emerge from the removal port 211, the removal port 211 can be closed. At that point, the clinician can correctly infer that most of the air previously within the housing 202 has been removed. However, small air bubbles or cavities may still be present within the housing 202.

[0030] In some cases, small air bubbles 212 may tend to remain, at least initially, near the inlet of the heat exchanger 206. If the priming fluid is allowed to continue to flow, after a period of time, most or all of the small air bubbles 212 may eventually flow out of the housing 202. However, in some cases, some of the small air bubbles 212 may remain, or the clinician may not want to prime long enough for all of the small air bubbles 212 to flow out of the housing 202.

[0031] An example of an oxygenator 220 with an integrated heat exchanger (or simply "oxygenator 220") is shown generally in Figure 4. Oxygenator 220 includes a housing 222. Housing 222 defines an inlet 223i and an outlet 223o. A blood flow path extends from inlet 223i to outlet 223o.

[0032] The heat exchanger 226 is disposed along the blood flow path. When blood (or priming fluid) enters the housing 222 through the inlet 223i, the blood typically flows radially toward the heat exchanger 226 and continuously flows radially into the heat exchanger 226. Temperature-controlled water also passes through the heat exchanger 226 from the inlet 227i to the outlet 227o. While the heat exchanger 226 allows for heat exchange between the temperature-controlled water and the blood, the walls of the heat exchanger 226 physically separate the temperature-controlled water from the blood (to prevent mixing), in a manner typical of heat exchangers. The heat exchanger 226 can be constructed of metal and / or polymeric materials. In some embodiments, the heat exchanger 226 is constructed of a plurality of thin tubes. An interior space 224 is defined by the heat exchanger 226. The incoming blood flows through the interior space 224 before reaching the heat exchanger 226.

[0033] In some embodiments, such as the illustrated embodiment, a flow distribution element 225 is disposed in the interior space 224. The flow distribution element 225 is configured to promote a substantially uniform radial flow distribution of blood as it enters the interior space 224 and transitions to enter the heat exchanger 226.

[0034] An oxygen supply 228 (also referred to as a "gas exchanger") is disposed within the housing 222 along the blood flow path after the heat exchanger 226. In some embodiments, the oxygen supply 228 is disposed concentrically around the heat exchanger 226 such that blood flowing radially through the heat exchanger 226 can flow radially through the oxygen supply 228 in succession. Gas is also passed through the oxygen supply 228 from an inlet 229i to an outlet 229o. The oxygen supply 228 can be comprised of hollow fibers (membranes) that allow gas transfer between the gas and blood (e.g., oxygen and carbon dioxide exchange) while preventing mixing of the gas and blood.

[0035] The ends of the individual tubular elements of the heat exchanger 226 and / or oxygen supply 228 may be physically joined with filler 230, as described above with reference to oxygenator 200. Removal ports 231 may also be included. In some embodiments, an optional arterial filtration material is also included within the oxygenator 220.

[0036] The oxygenator 220 further includes one or more porous hollow fibers 232. In the illustrated embodiment, the one or more porous hollow fibers 232 are disposed within the interior space 224 along the blood flow path prior to the heat exchanger 226. In some embodiments, the one or more porous hollow fibers 232 are disposed within the heat exchanger 226. That is, in some embodiments, the one or more porous hollow fibers 232 are interspersed within the physical material (e.g., tubes, etc.) of the heat exchanger 226. In certain embodiments, the one or more porous hollow fibers 232 are disposed within the interior space 224 along the blood flow path prior to the heat exchanger 226 and are also disposed within the heat exchanger 226.

[0037] In some embodiments, the one or more porous hollow fibers 232 are formed from polypropylene fibers. In certain embodiments, the diameter of the one or more porous hollow fibers 232 may be about 170 μm, or about 300 μm, or any other suitable size. The one or more porous hollow fibers 232 have pores sized to allow air to enter the inside of the one or more porous hollow fibers 232 while preventing liquid from entering the inside of the one or more porous hollow fibers 232. Thus, the one or more porous hollow fibers 232 facilitate removing air from the interior space 224. The hydrostatic pressure and dynamic pressure (from the momentum of the flow) of the priming fluid (or blood) can provide the driving force for the air to enter the one or more porous hollow fibers 232, respectively.

[0038] The one or more porous hollow fibers 232 have a free end 232e that is an open end. In the illustrated embodiment, the free end 232e is located in the environmental space within or around the blood oxygenator 220. Thus, the interior of the one or more porous hollow fibers is fluidly connected to the environmental space within or around the blood oxygenator 220. That is, air entering the one or more porous hollow fibers 232 can exit the environmental space within or around the blood oxygenator 220 from the free end 232e. In some embodiments, the free end 232e is positioned to ventilate the same space as the oxygenator 228. That is, air entering the one or more porous hollow fibers 232 can exit the same space as the oxygenator 228 from the free end 232e and can exit the oxygenator 220 from the gas outlet 229o.

[0039] In some embodiments, the free ends 232e are connected to a vacuum source (not shown) such that use of a vacuum source results in a greater pressure differential (driving force) that can facilitate removal of air in a better manner (as compared to simply venting one or more of the porous hollow fibers 232 to the surrounding atmosphere).

[0040] In some embodiments, one or more of the porous hollow fibers 232 may be physically bonded (at least partially) to other portions of the oxygenator 220 using the filler 230. In the illustrated embodiment, unlike the heat exchanger 226 and the oxygenator 228, the ends of the one or more of the porous hollow fibers 232 are not exposed by shearing off the filler 230 (because the free ends 232e are already exposed to the surrounding atmosphere). Alternatively, or in addition, in some embodiments, the ends of one or more portions (or all) are exposed as a result of shearing off or otherwise removing some of the filler 230.

[0041] 5 illustrates the priming process of oxygenator 220. Priming fluid is pumped into housing 222 through inlet 223i. The priming fluid enters interior space 224 where it may impinge on flow distribution element 225. The priming fluid then flows in a generally radial direction into heat exchanger 226. From heat exchanger 226, the priming fluid flows in a generally radial direction into oxygen supply 228. After passing through oxygen supply 228, the priming fluid fills the remainder of the space within housing 222 before exiting oxygenator 220 through outlet 223o.

[0042] As the priming fluid flows in the manner described above, air within the housing 222 is displaced with the priming fluid. At least some of the displaced air is permitted to exit the housing via the removal port 231. Once priming fluid begins to emerge from the removal port 231, the removal port 231 can be closed. At that point, the clinician can correctly infer that most of the air previously within the housing 222 has been removed. However, small air bubbles or cavities may still be present within the housing 222.

[0043] In the illustrated embodiment, the oxygenator 220 includes one or more porous hollow fibers 232. Thus, if small air bubbles or cavities are still present within the housing 222, the air will tend to enter the one or more porous hollow fibers 232. After entering the one or more porous hollow fibers 232, the air can exit the one or more porous hollow fibers 232 via the free ends 232e into the environmental space within or around the blood oxygenator 220. In this manner, the one or more porous hollow fibers 232 facilitate the removal of air within the oxygenator 220 during the priming process. Additionally, if air is present in or entrained with the circulating blood during a medical procedure using the oxygenator 220, the one or more porous hollow fibers 232 serve to remove such air.

[0044] An example of an oxygenator 240 (including an integral heat exchanger) is shown in an exploded cross-sectional perspective view in Figure 6. The oxygenator 240 includes a blood inlet 242 extending from an end wall 243 and a blood outlet 244 extending from a peripheral housing 245. As blood flows between the blood inlet 242 and the blood outlet 244, the blood passes through a heat exchanger 248 and an oxygenator fiber bundle 250. In some embodiments, one or more filter members may be included in the blood flow path within the oxygenator module 240. The heat exchanger 248 defines an interior space 241.

[0045] In some embodiments, an optional flow distribution element 249 may be included in the oxygenator module 240. The flow distribution element 249 can promote a desired flow distribution of the blood (e.g., in some embodiments, a substantially uniform radial flow distribution) as the blood passes from the interior space 241 to the heat exchanger 248.

[0046] The oxygenator 240 also includes a first water flow port 246a and a second water flow port 246b. The water flow ports 246a and 246b allow for the inflow and outflow of water for cooling or heating the blood via a heat exchanger 248. The oxygenator 240 also includes a gas inlet (not shown) and a gas outlet 252. The gas inlet and gas outlet 252 allow for the inflow and outflow of oxygen-enriched gas for oxygenating the blood via an oxygenator fiber bundle 250. The oxygenator 240 includes two end caps 247a and 247b that help structurally hold the parts of the oxygenator module 240 together and define annular manifolds for the water and oxygen-enriched gas. The oxygenator 240 also includes other parts such as a removal port 254, and various other parts known to those skilled in the art.

[0047] In the illustrated embodiment, the oxygenator 240 also includes an optional flow distribution element 260 (which may also be referred to as a "heat exchanger body") disposed within the interior space 241. The flow distribution element 260 may then promote blood to flow into the interior space 241 in a substantially uniform radial flow pattern. The flow distribution element 260 has a frusto-conical shape. In some embodiments, the flow distribution element 260 includes one or more ribs 262. The ribs 262 may be formed and oriented on an outer surface of the flow distribution element 260 to allow blood to flow into the interior space 241 to substantially fill the interior space 241 before flowing in a substantially uniform radial flow pattern.

[0048] 7, in some embodiments, oxygenator 240 also includes one or more porous hollow fibers 270. The one or more porous hollow fibers 270 may be disposed within oxygenator 240 in relation to other portions of oxygenator 240, as described above with reference to oxygenator 220.

[0049] In the illustrated embodiment, the one or more porous hollow fibers 270 are wrapped around the flow distribution element 260. In particular, in the illustrated embodiment, the one or more porous hollow fibers 270 are wrapped around the flow distribution element 260 in a crossing pattern. Such a crossing pattern may be a helical pattern. In some embodiments, the winding density of the one or more porous hollow fibers 270 is higher at the ends of the flow distribution element 260 compared to the winding density of the one or more porous hollow fibers 270 inwardly from the ends. Any suitable winding pattern (e.g., pitch, angle, number of turns, spacing between turns, etc.) may be used. Any number of fibers (individual hollow fibers) may be used. For example, but not limited to, in some examples, 1 fiber, 2 fibers, 4 fibers, 8 fibers, 16 fibers, 32 fibers (or any other number of fibers) may be used (and wrapped in a desired pattern).

[0050] When a crossing pattern is used (e.g., as illustrated, but not limited to, in FIG. 7), in some cases cross-like communication between the fibers of the one or more porous hollow fibers 270 may be advantageously formed. That is, the intersections of the microporous fibers may form gas communication bridges that allow gas (e.g., air) to move radially (between adjacent fibers) as well as longitudinally. This communication may be very useful for venting the one or more porous hollow fibers 270 from the blood flow path to the atmosphere. Instead of all the fibers that need to be vented from the oxygenator 240, a smaller number of the one or more porous hollow fibers 270 may be used to vent trapped air. This attribute may aid in ease of manufacture in some cases.

[0051] In some embodiments, the one or more porous hollow fibers 270 may be arranged in a non-intersecting pattern within the oxygenator 240. In some such embodiments, the longitudinal axis of the one or more porous hollow fibers 270 may be parallel to a central longitudinal axis of the oxygenator 240. In some such embodiments, the longitudinal axis of the one or more porous hollow fibers 270 may be oriented at a non-zero angle (e.g., between about 0 and 10 degrees, between about 5 and 15 degrees, or between about 10 and 20 degrees, or between about 15 and 25 degrees, or between about 20 and 30 degrees, etc.) relative to the central longitudinal axis of the oxygenator 240. In some embodiments, the one or more porous hollow fibers 270 may be a mat of hollow fibers. One or more layers of such a mat of hollow fibers may be used.

[0052] In some embodiments, one or more of the porous hollow fibers 270 may be used for gas transfer purposes, such as, but not limited to, oxygenating blood and / or removing carbon dioxide from the blood.

[0053] 8 is a photograph of the end of an extracorporeal oxygenator 300 (and integrated heat exchanger) including an integrated air removal structure according to some embodiments described herein. The end cap of the oxygenator 300 is not included in the photograph to allow better visualization of the following components of the oxygenator 300.

[0054] The oxygenator 300 includes an oxygen supply 310, a heat exchanger 320, a flow distribution element 330, and one or more porous hollow fibers 340. In the illustrated embodiment, a notch 332 is included in the end of the flow distribution element 330. In some embodiments, the notch 332 is formed (e.g., machined) after the filling process, such that an open end of the one or more porous hollow fibers 340 is formed to allow air to vent from the one or more porous hollow fibers 340 to the atmosphere.

[0055] Although the present specification contains specific implementation details, these should not be construed as limitations on the scope of any invention or scope of claims, but rather as descriptions of features that may be specific to certain embodiments of a particular invention. Certain features described in the context of separate embodiments herein may also be combined and implemented in a single embodiment. Conversely, various features described in the context of a single embodiment may also be implemented in multiple embodiments separately or in suitable subcombinations. Furthermore, although features may be described and initially claimed herein as working in a certain combination, in some cases one or more features may be excised from the claimed combination. Also, the claimed combinations may be directed to subcombinations or variations of the subcombinations.

[0056] Similarly, although operations are illustrated in the figures in a particular order, this should not be understood as requiring that such operations be performed in the particular order or sequential order as illustrated, or that all of the illustrated operations be performed, to achieve desired results. In certain circumstances, multitasking and parallel processing may be advantageous. Furthermore, the separation of various system modules and components in the embodiments described herein should not be understood as requiring such separation in all embodiments, and it should be understood that the program components and systems described may generally be integrated in a single product or packaged into multiple products.

[0057] Although several embodiments of the subject matter have been described, other embodiments are within the scope of the following claims. For example, the actions recited in the claims may be performed in a different order and still achieve desirable results. By way of example, the processes depicted in the accompanying figures do not necessarily require the particular order shown, or sequential order, to achieve desirable results. In certain implementations, multitasking and parallel processing may be advantageous. The following is a summary of the claims as originally filed: [1] A blood oxygenation device comprising: a blood inlet and a blood outlet, and a blood flow path extending from the blood inlet to the blood outlet; A gas exchange section disposed along the blood flow path; a heat exchange unit disposed along the blood flow path prior to the gas exchange unit; one or more porous hollow fibers positioned along the blood flow path prior to the heat exchange portion. [2] The blood oxygenator of [1], wherein the interior of the one or more porous hollow fibers is in communication with an environmental space within or around the blood oxygenator. [3] The blood oxygenator of [1], wherein the interior of the one or more porous hollow fibers is in communication with a vacuum source. 4. The blood oxygenator of claim 1, further comprising a flow distribution element positioned along the blood flow path prior to the one or more porous hollow fibers. [5] The blood oxygenator of [4], wherein the one or more porous hollow fibers are wrapped around the flow distribution element. [6] The blood oxygenator of [5], wherein the one or more porous hollow fibers are wound around the flow distribution element in an intersecting helical pattern. [7] The blood oxygenator of [4], wherein the one or more porous hollow fibers are arranged around the flow distribution element in a non-intersecting pattern. [8] The blood oxygenation device described in [1], wherein the pores of the one or more porous hollow fibers allow air to enter the inside of the one or more porous hollow fibers while preventing liquid from entering the inside of the one or more porous hollow fibers. [9] A blood oxygenation device comprising: a housing defining a blood inlet and a blood outlet; a heat exchanger disposed within the housing and defining an interior space; A membrane oxygenator unit is disposed within the housing and concentrically disposed around the heat exchanger; and one or more porous hollow fibers disposed within said interior space.

[10] The blood oxygenation device of [9], further comprising a flow distribution element disposed within the interior space.

[11] The blood oxygenator of

[10] , wherein the one or more porous hollow fibers are wrapped around the flow distribution element.

[12] The blood oxygenator of

[11] , wherein the flow distribution element is configured to promote a substantially uniform radial flow distribution of blood entering the heat exchanger.

[13] The blood oxygenator of [9], wherein an interior of the one or more porous hollow fibers is in communication with an environmental space within or around the blood oxygenator.

[14] The blood oxygenator of [9], wherein the interior of the one or more porous hollow fibers is in communication with a vacuum source.

[15] The blood oxygenator of [9], wherein the one or more porous hollow fibers are arranged in a cross pattern.

[16] The blood oxygenator of [9], wherein the one or more porous hollow fibers are arranged in a non-intersecting pattern.

[17] A method of constructing a blood oxygenator, comprising the steps of: disposing a membrane oxygenator within a housing defining (i) a blood inlet, (ii) a blood outlet, and (iii) a blood flow path extending from said blood inlet to said blood outlet; disposing a heat exchanger along the blood flow path prior to the membrane oxygenator; and disposing one or more porous hollow fibers along the blood flow path prior to the heat exchanger.

[18] The method of

[17] , wherein the one or more porous hollow fibers are arranged such that an interior of the one or more porous hollow fibers is in communication with an environmental space within or around the blood oxygenator.

[19] The method of

[17] , further comprising positioning a flow distribution element along the blood flow path prior to the one or more porous hollow fibers, the one or more porous hollow fibers being wrapped around the flow distribution element.

[20] The method of

[17] , wherein the pores of the one or more porous hollow fibers allow air to enter the inside of the one or more porous hollow fibers while preventing liquid from entering the inside of the one or more porous hollow fibers.

Claims

1. 1. A blood oxygenation device comprising: a blood inlet, a blood outlet, and a blood flow path extending from the blood inlet to the blood outlet; A gas exchange section disposed along the blood flow path; a heat exchange unit disposed along the blood flow path prior to the gas exchange unit, the gas exchange unit being disposed concentrically around the heat exchange unit; one or more porous hollow fibers disposed along the blood flow path prior to the heat exchange portion; a flow distribution element disposed along the blood flow path prior to the one or more porous hollow fibers; the pores of the one or more porous hollow fibers allow air to enter the interior of the one or more porous hollow fibers while preventing liquid from entering the interior of the one or more porous hollow fibers; the flow distribution element comprises an outer surface having a frustoconical shape extending from a first end to a second end of the flow distribution element, and one or more ribs on the outer surface; the one or more porous hollow fibers extend around the flow distribution element in a crisscross pattern with spaces between the porous hollow fibers. Blood oxygenator.

2. 10. The blood oxygenator of claim 1, wherein an interior of said one or more porous hollow fibers communicates with an exterior environmental space within or around said blood oxygenator.

3. 10. The blood oxygenator of claim 1, wherein an interior of said one or more porous hollow fibers is in communication with a vacuum source.

4. 10. The blood oxygenator of claim 1, wherein the one or more porous hollow fibers are wrapped around the flow distribution element in a helical pattern.

5. 1. A blood oxygenation device comprising: a housing defining a blood inlet and a blood outlet; a blood flow path extending from the blood inlet to the blood outlet; a heat exchanger disposed within the housing and defining an interior space; a flow distribution element disposed within the interior space; A membrane oxygenator unit is disposed within the housing and concentrically disposed around the heat exchanger; and one or more porous hollow fibers disposed in the interior space along the blood flow path prior to the heat exchanger; the one or more porous hollow fibers extend around the flow distribution element in a crossing pattern with spaces between the porous hollow fibers; the flow distribution element defines a notch at an end of the flow distribution element; an open end of the one or more porous hollow fibers aligned with the notch to allow air to escape from the one or more porous hollow fibers; Blood oxygenator.

6. The blood oxygenator of claim 5 , wherein the flow distribution element is configured to promote a substantially uniform radial flow distribution of blood entering the heat exchanger.

7. 6. The blood oxygenator of claim 5, wherein an interior of the one or more porous hollow fibers communicates with an exterior environmental space within or around the blood oxygenator.

8. 6. The blood oxygenator of claim 5, wherein an interior of said one or more porous hollow fibers is in communication with a vacuum source.

9. 6. The blood oxygenator of claim 5, wherein the one or more porous hollow fibers are arranged in a helical pattern.

10. 1. A method of configuring a blood oxygenator, the method comprising: disposing a membrane oxygenator within a housing defining (i) a blood inlet, (ii) a blood outlet, and (iii) a blood flow path extending from said blood inlet to said blood outlet; disposing a heat exchanger along the blood flow path prior to the membrane oxygenator, the membrane oxygenator being concentrically disposed about the heat exchanger; positioning a flow distribution element along the blood flow path prior to the heat exchanger; wrapping one or more porous hollow fibers around the flow distribution element in a cross pattern with spaces between the porous hollow fibers; the pores of the one or more porous hollow fibers allow air to enter the interior of the one or more porous hollow fibers while preventing liquid from entering the interior of the one or more porous hollow fibers. method.

11. 11. The method of claim 10, wherein the one or more porous hollow fibers are arranged such that an interior of the one or more porous hollow fibers is in communication with an exterior environmental space within or around the blood oxygenator.

12. 2. The blood oxygenator of claim 1, wherein the one or more porous hollow fibers are wrapped more densely at the ends of the flow distribution element than at the interior of the flow distribution element.

13. 6. The blood oxygenator of claim 5, wherein the one or more porous hollow fibers are wrapped more densely at the ends of the flow distribution element than at the interior of the flow distribution element.

14. The method of claim 10 , wherein the one or more porous hollow fibers have a higher winding density at the ends of the flow distribution element than at the interior of the flow distribution element.

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