EP0764045A1 - Ecartement par monofilaments de membranes fibreuses et creuses et dispositifs d'oxygenation du sang comprenant ces membranes - Google Patents

Ecartement par monofilaments de membranes fibreuses et creuses et dispositifs d'oxygenation du sang comprenant ces membranes

Info

Publication number
EP0764045A1
EP0764045A1 EP95921440A EP95921440A EP0764045A1 EP 0764045 A1 EP0764045 A1 EP 0764045A1 EP 95921440 A EP95921440 A EP 95921440A EP 95921440 A EP95921440 A EP 95921440A EP 0764045 A1 EP0764045 A1 EP 0764045A1
Authority
EP
European Patent Office
Prior art keywords
hollow fiber
membrane
monofilament
blood
fiber membranes
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP95921440A
Other languages
German (de)
English (en)
Inventor
Frederick J. Reinhart
R. Sykes Carter
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Baxter International Inc
Original Assignee
Baxter International Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Baxter International Inc filed Critical Baxter International Inc
Publication of EP0764045A1 publication Critical patent/EP0764045A1/fr
Withdrawn legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
    • B01D69/08—Hollow fibre membranes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2313/00—Details relating to membrane modules or apparatus
    • B01D2313/14—Specific spacers
    • B01D2313/146—Specific spacers on the permeate side

Definitions

  • the present invention pertains generally to medical equipment and, more particularly, to improved hollow fiber semi-permeable membranes having monofilamentous spacer member(s) spirally disposed on the outer surface thereof, and extracorporeal gas exchange devices incorporating such hollow fiber semi-permeable membranes.
  • Extracorporeal blood oxygenation systems are typically utilized to a) oxygenate and b) remove carbon dioxide from the blood of patients whose cardiopulmonary function has been interrupted.
  • the most common clinical situations wherein extracorporeal blood oxygenation systems are utilized is during cardiothoracic surgical procedures wherein cardiopulmonary bypass is employed.
  • the typical extracorporeal blood oxygenation system in use today comprises a rigid housing having a multiplicity of tubular semi-permeable membranes known as "hollow fiber membranes" disposed therewithin. Pure oxygen or an oxygen- containing gas mixture is channeled through the lumens of the hollow fiber membranes, while the patient's blood is passed over the outer surfaces of the hollow fiber membranes. Contact of the patient's blood with the outer surfaces of the membranes permits oxygen to diffuse through the membranes and into the blood, with concomitant back- diffusion of carbon dioxide from the blood and into the gas.
  • the partial pressures of oxygen (P0 2 ) and carbon dioxide (PC0 2 ) are influenced by numerous factors including; a) the available surface area for gas exchange (i.e., the area wherein blood actually contacts the outer surfaces of the hollow fiber membranes; b) the relative concentrations of oxygen and carbon dioxide in the gas mixture; c) the pressure of the gas mixture within the lumens of the hollow fiber membranes; d) the flow rate of blood over the outer surfaces of the hollow fiber membranes; e) the film thickness of blood passing over the outer surfaces of the hollow fiber membranes; and f) the pressure and flow rate of blood passing over the outer surfaces of the hollow fiber membranes.
  • variable of "blood film thickness” is largely a function of the design of the device and is primarily dictated by the size of the spaces which exist between the individual hollow fibers within the device. Inconsistencies or variations in spacing between the individual membranes may result in large variations in oxygenator efficiency due to varying blood film thicknesses (i.e., too thick or too thin) and/or the presence of "dead spots" (i.e., constricted areas where blood does not flow) within the fiber network.
  • U.S. Patent No. 4,293,418 purports to describe the use of spacer yarns wrapped about the outer surfaces of individual hollow fibers to maintain a prescribed spacing between the individual hollow fibers.
  • the individual spacer yarns described in U.S. Patent No. 4,293,418 are characterized as textured yarn which is spirally wound so that substantially equal and consistent spaces are formed between the hollow fibers (Col. 2, Line 67-Col. 3, Line l).
  • 4,293,418 (Fuji, et al.) are purported to maintain specific spacing between individual hollow fibers in various types of fluid separation apparatus, the use of such textured yarns as to space individual hollow fiber membrane in a blood oxygenator device may be less than desirable due to the fact that the textured yarn may act as a filtering medium such that blood will filter through the texture of the yarn, rather than simply passing around the individual yarns. Such filtering effect of the textured yarn may result in retention of blood cells within the textured yarn and on attendant potential for thrombogenic clot formation.
  • the multifilament yarns made of many fine fibers present a greater than necessary inactive surface area which is contacted by the blood, such unnecessary surface contact presenting an increased chance of inducing an undesirable bioreactive clotting response or other bioincompatability reaction due to contact of the blood with the constituents of the yarn surfaces with which the blood comes in contact.
  • yarn may tend to flatten out or compress against the hollow fiber membranes, thereby resulting in a change of the desired spacer width resulting from the yarn with a resultant variation or change in the blood flow space (i.e., blood film thickness) between adjacent gas exchange surfaces of the individual hollow fiber membranes.
  • Another problem associated with multifiliament textured "yarns” is that such yarns tend to flatten and spread out upon compression thereof, thereby covering more of the surface of the adjacent hollow fiber membrane than is necessary to effect the desired spacing function.
  • multifilament textured "spacer yarns” are less than optimal when employed for purposes of maintaining specific lateral spacing between adjacent hollow fiber membranes.
  • Another prior art method of spacing hollow fiber membranes as described in Japanese Kokai Patent Application No. HEI3[1991]-278821 (Fuji), utilized two spacer yarns wound in spiral fashion on the outer surface of the hollow fiber membrane, such that the "spacer yarns" repeatedly cross one another in opposite directions. Such oppositely wound crossing spacer yarns may be monofilament.
  • oppositely wound crossing "spacer yarns" of HE13(1991)-278821 can not perform a consistent spacing function because they overlap one another at cross-points, such overlapping of the "spacer yarns” resulting in a doubling of the spacer yarn width at the repetitive cross-point.
  • the cross-points of the spacer yarns of HE13(1991)-278821 would result in approximately two times the desired spacing because of the overlapping or crossing of the individual "spacer yarn” elements.
  • elongate tubular hollow iber membranes having one or more monofilament spacer member(s) disposed or formed on the outer surfaces thereof.
  • the monofilament spacer member(s) is/are disposed or formed in a spiral configuration.
  • two or more spiral monofilament spacer members may be ' disposed or formed on a single tubular hollow fiber membrane in accordance with the present invention, it is preferable that such spiral monofilament spacer members not overlap or cross one another at any point so as not to block or disrupt laminar blood flow over the outer surfaces of the hollow fiber membranes.
  • a separate monofilament member e.g., a monofilamentous thread or line
  • a tubular hollow fiber membrane e.g., a monofilamentous thread or line
  • the spiral monofilament spacer member may be formed as a raised spiral rib of solid or monofilamentous construction on the outer surface of the hollow fiber membrane.
  • Such raised monofilamentous rib may be formed by creating a notch or recess in an extrusion dye utilized to extrude the tubular hollow fiber membrane. Rotational force may then be applied to the extrusion dye, and/or to the extruded hollow fiber emerging therefrom, so as to cause the extruded rib to assume the desired spiral configuration to the raised rib on the outer surface of the tubular membrane.
  • hollow fiber membranes having the spiral monofilament spacer member of the above-described first or second embodiment may be operatively disposed (e.g., packed) in close-spaced parallel, side-by-side relation to one another such that the spiral monofilamentous member of each membrane is in abutment with the outer surface of an adjacent membrane.
  • the spiral monofilament spacer members disposed or formed on the outer surfaces of adjacent side- by-side positioned membranes will serve to define and maintain consistent prescribed spacing distances between the outer surfaces of such adjacent membranes.
  • the spiral monofilament spacer members disposed or formed on the outer surfaces of membranes which are positioned next to a solid bulkhead or wall of a housing will serve to maintain specific prescribed spacing between the outer surfaces of such membranes and the adjacent bulkhead or wall.
  • an extracorporeal membrane oxygenation device which incorporates the spirally wound or spirally ribbed hollow fiber membranes of the above-described first and/or second embodiment therein such that the membranes- are disposed in close-spaced generally parallel side-by-side relation to one another with the monofilamentous member or rib of each such membrane being in abutment with the outer surface of an adjacent membrane so as to define and maintain prescribed and consistent spacing therebetween.
  • a group or packet of individual hollow fiber membranes positioned in close-spaced parallel side-by-side relation to one another may be positioned within a membrane oxygenator or other extracorporeal blood processing device and a flow of blood is channeled or passes over the outer surfaces of the hollow fiber membranes such that the spiral monofilament spacer members disposed on the outer surfaces of the hollow fiber membranes will guide the path of the blood flow over the outer surfaces of the membranes.
  • the spiral monofilament spacer members will serve to cause the blood to flow in a spiral flow path.
  • the spiral monofilament spacer members will cause the blood to undergo periodic deflection or offsetting each time the blood flow comes into contact with or impinges against one of the spiral monofilament spacer members.
  • Figure 1 is a perspective view of an individual hollow fiber membrane having a monofilament spacer of the present invention spirally disposed on the outer surface thereof.
  • Figure 2 is an enlarged perspective view of two side- by-side hollow fiber membranes having monofilament spacers of the present invention disposed thereon.
  • Figure 2a is a partial elevational view of a portion of Figure 2.
  • Figure 3a is a perspective view of a heat exchanger/membrane oxygenator device having the monofilament-spaced hollow fiber membrane of the present invention incorporated therein.
  • Figure 3b is a top plan view of the membrane oxygenator device shown in Figure 3.
  • Figure 3c is an exploded view of the blood heat exchanger/membrane oxygenator device of Figure 3a.
  • Figure 3d is a cross-sectional view through line 3d-3d of Figure 3a.
  • Figure 4 is a cut-away elevational view of the heat exchanger/membrane oxygenator device of Figure 3.
  • Figure 4a is a cross-sectional view of a portion of the heat exchanger/membrane oxygenator device of Figure 4.
  • Figure 4b is an enlarged cross-sectional view of region 4b of Figure 4a.
  • Figure 5a is a perspective view of an extrusion die which may be utilized to manufacture the hollow fiber membranes of the second embodiment of the present invention having a spiral monofilamentous rib formed on the outer surface thereof.
  • Figure 5b is a perspective view of a hollow fiber membrane of the second embodiment of the present invention emerging from the extrusion die of Figure 5a.
  • Figure 6 is a schematic diagram of a continuous manufacturing method whereby a continuous hollow fiber membrane is a) passed through a pirn apparatus which wraps a monofilament spirally about the outer surface of the hollow fiber membrane and b) subsequently wound onto a core component of a blood processing apparatus, such as a membrane oxygenator device.
  • a blood processing apparatus such as a membrane oxygenator device.
  • Figure 6a is an enlarged perspective view of segment
  • each preferred hollow fiber membrane 10 of the present invention comprises a tubular semi-permeable membrane having an outer surface 14 and a hollow lumen 16 which extends longitudinally through the membrane 10.
  • One or more monofilamentous spacer members are disposed upon or formed upon the outer surface 14 of the membrane 10.
  • Each membrane 10 has a semipermeable tubular wall of substantially consistent thickness T.
  • Each monofilamentous spacer member 12 on the membrane 10 has a cross-sectional dimension (e.g., diameter) spacer width SW.
  • Abutment of each spacer 12 against an adjacent surface will serve to hold the outer surface 14 of the membrane 10 upon which the spacer 12 is disposed a distance of one spacer width SW from the outer surface 14 of an adjacent membrane and/or any adjacent surface of the device against which the spacer 12 is abutted.
  • the hollow fiber membranes 10 of the present invention will preferably be formed of semi-permeable materials suitable for blood-gas exchange including cellulose esters such as cellulose diacitate and cellulose triacetate, cellulose derivatives such as cellulose ether, polyamide, polyester, methacrylic or acrylic polymers such as polymethyl methacrylate, polyurethane, organic silicone polymer, polyacrylonitrile and copolymer thereof, polysulfones, and polyolefins such as polyethylene and polypropylene.
  • the hollow fiber membranes 10 are extruded to a preferred wall thickness T in the range of 40-60 microns and have a preferred inner luminal diameter ID in the range of 270-290 microns and a preferred outer diameter OD in the range of 350-410 microns.
  • the spiral spacer member 12 of the present invention preferably has an effective spacer width SW (e.g., the diameter if the spacer is of round cross- sectional configuration) of 38-63 microns.
  • the longitudinal distance within which the spacer member 12 makes one full spiral revolution about the outer surface 14 of the membrane 10 is referred to herein as the "pitch interval" P.
  • the spiral monofilament spacer member(s) 12 In blood membrane oxygenator applications wherein the wall thicknesses T of the hollow fiber membranes 10 are in the preferred range of 40-60 microns, it will typically be preferable for the spiral monofilament spacer member(s) 12 to have pitch intervals P in the range of 2.6-3.7 millimeters.
  • each spacer member 12 makes contact with the outer surface 14 of an adjacent hollow fiber membrane 10 will be sufficiently close together to result in a consistently sized gap or space between the adjacent outer surfaces 14 equal to the spacer width SW or diameter of the spacer member(s) 12.
  • the prescribed pitch interval P may be varied depending on the relative pliability, flexibility or wall thickness T of the hollow fiber membrane 10.
  • the hollow fiber membranes 10 are relatively flexible or pliable, it may be desirable to utilize a short pitch interval P so as to minimize the distance between the points at which each spacer member 12 contacts the outer surface 14 of an adjacent hollow fiber membrane 10.
  • longer pitch intervals P may be employed so as to maximize the distance between the points at which each spacer member 12 contacts the outer surface 14 of an adjacent hollow fiber membrane 10.
  • hollow fiber membranes 10 of the present invention may be wrapped, laid, wound, or otherwise deployed into any shape of channel or receiving structure, and will conform to the shape of the particular channel or receiving structure while maintaining constant surface-to- surface spacing between the outer surfaces of individual hollow fiber membranes 10. Additionally, the hollow fiber membranes 10 of the present invention will also maintain constant desired spacing between the outer surfaces of the hollow fiber membranes 10 and any adjacent structural members, bulkheads or walls of the particular housing, groove or channel into which the hollow fiber membranes 10 have been placed.
  • the monofilament-spaced hollow fiber membranes 10 of the present invention may be incorporated into many different types and sizes of blood oxygenators.
  • One particular blood oxygenator device wherein the hollow fiber membranes 10 of the present invention may be incorporated is that described in United States Patent No. 5,120,501 and sold commercially as the UnivoxTM Membrane Oxygenation System, Baxter Healthcare Corporation, Bentley Laboratories Division, Irvine, California 92714.
  • the membrane oxygenator device of United States Patent No. 5,120,501 is shown in Figures 3, 4, and 5 of this patent application for purposes of describing how the hollow fiber membranes 10 of the present invention may be incorporated into that particular membrane oxygenator device. Additionally, the entire disclosure of United States Patent No. 5,120,501 is expressly incorporated herein by reference.
  • the heat exchanger/membrane oxygenator device 40 shown is connectable to an extracorporeal blood circuit for purposes of a) controlling the blood temperature and b) maintaining the P0 2 and PC0 2 of the blood within prescribed ranges.
  • the heat exchanger/membrane oxygenator device 40 comprises an outer housing or shell 42 within which there is mounted a heat exchange body or bellows 44 and a heat exchange jacket 46.
  • the bellows 44 comprises a generally cylindrical body or core having a series of annular ribs or pleats 48 formed circumferentially about the outer surface thereof.
  • the series of annular ribs 48 define a corresponding series of annular, generally parallel, blood receiving grooves or channels 50 between adjacent ribs 48.
  • the heat exchange jacket 46 comprises a generally cylindrical wall 54 having a plurality of annular flanges or ribs 56 extending about the outer surface thereof so as to form a continues fluid flow path through which heat exchange fluid may be passed about the outer surface of the cylindrical wall 54 and into contact with the surrounding inner surface of bellows 44.
  • the circulation of heat exchange fluid through the flow path 58 between the cylindrical wall 54 and the surrounding bellows 44 will operate to either heat or cool the bellows 44 thereby concomitantly heating or cooling the blood passing through the blood passage channels 50 on the outer surface of bellows 44.
  • a single elongate hollow fiber membrane 10 is repeatedly wound about the outer surface of the bellows 44 such that multiple convolutions of the hollow fiber membrane 10 become disposed within each channel 50 on the outer surface of bellows 44, with each such convolution being in generally parallel side-by-side position to an adjacent convolution.
  • a vertical cut is subsequently made through the long hollow fiber membrane such that each convolution becomes an individual hollow fiber membrane 10 wound about the outer surface of bellows 44 such that a separate individual group or packet 84 of hollow fiber membranes 10 arranged in substantially parallel side-by-side relation to one another, resides within each channel 50.
  • Each individual group 84 of hollow fiber membranes 10 preferably consists of approximately 240-260 individual hollow fiber membranes 10 laid or wound into each channel 50.
  • the monofilament spacer member 12 e.g., separate monofilament member or raised rib
  • the monofilament spacer member 12 disposed or formed thereon will abut against the adjacent rob or pleat 48, thereby maintaining consistent prescribed spacing between the outer surfaces of those hollow fiber membranes 10 and the adjacent surfaces of the bellows 44.
  • a space occupying member such as a spiral plastic spring may be placed in the bottom region of each channel 50 to prevent the hollow fiber membranes 10 from packing all the way down into the bottom portion of the channel 50.
  • the presence of the space occupying members (e.g., plastic spring) in the bottom portion of each channel 50 will form a blood passage gap 86 in the innermost region of each channel 50.
  • blood may be initially shunted or channeled into the blood flow gap 86 at the base of each channel 50 and subsequently permitted to percolate or pass outwardly over the outer surfaces of the individual hollow fiber membranes 10 grouped in each such channel 50.
  • the direction of the initial outward blood flow is generally perpendicular to the longitudinal axes of the hollow fiber membranes 10 disposed in each channel 50.
  • the blood will come into contact with the monofilament spacer members 12 disposed or formed on the outer surfaces of the individual hollow fiber membranes 10.
  • Each such contact or impingement against a spiral spacer member causes the flowing blood to undergo lateral deflection or shifting in the direction of the longitudinal axis of the hollow fiber 10.
  • a single spiral monofilamentous spacer member 12 disposed on the outer surface of each hollow fiber membrane 10 will serve the additional function of creating a desired spiral or laterally shifted flow path of the blood as it passes over the outer surfaces 14 of the hollow fiber membranes 10.
  • This aspect of the present invention is specifically illustrated by the arrows on Figure 2a.
  • This flow directing or flow channeling function of the single monofilamentous spacer members 12 could not be achieved by multiple spacer members wrapped in opposite criss-crossing directions as described in Japanese Kokai Patent Application No.
  • the initial shunting or channeling of the blood into each gap 86 allows the blood to initially come in contact with the adjacent outer surface 48 of the bellows 44 so as to immediately effect warming or cooling of the blood in accordance with the temperature of the heat exchange medium being circulated on the inner surface of the bellows 44.
  • the blood being circulated through the device 40 will be at a controlled temperature before it begins to percolate or flow outwardly from the gap 86, over the gas exchanging outer surfaces of the individual hollow fiber membranes 10.
  • the opposite ends of the hollow fiber membranes 10 of each packet 84 are anchored within a solid potting material which forms a solid block 78 on the back of a blood inlet manifold 60.
  • the back surface 79 of the potting material 78 is flush cut such that the open ends of the hollow fiber lumens 16 form openings at surface 79 to permit gas to flow into and out of such lumens 16 of membranes 10. Passage of the desired gas or gas mixture through the lumens 16 of the individual hollow fiber membranes 10 is facilitated by a gas passage manifold 70 positioned on one side of the shell 42 of the device 40, immediately outboard of the blood inlet manifold 60.
  • Gas passage manifold 70 comprises a rigid shell or casing having a generally hollow interior with a solid bulkhead 72 extending vertically through the mid-region thereof.
  • the bulkhead 72 divides the inner chamber of the gas passage manifold 70 into a gas inlet chamber 74 and a gas outlet chamber 76.
  • the first (inlet) ends of the hollow fiber membranes 10 are disposed in a vertical column along the left side of the potting material block 78 so as to be in alignment and fluidic contact with gas inlet chamber 74 of gas manifold 70.
  • the second ends of the hollow fiber membranes 10 are disposed in a vertical column on the right side of the potting material block 78 so as to be positioned in alignment and fluidic contact with gas outlet chamber 76 of the gas manifold 70.
  • a gas or gas mixture i.e., pure oxygen, oxygen/air mixture, oxygen/nitrogen mixture
  • a gas or gas mixture i.e., pure oxygen, oxygen/air mixture, oxygen/nitrogen mixture
  • the gas or gas mixture will pass outwardly through the second ends of the lumens 16 of the hollow fiber membranes 10 and into the gas outlet chamber 76 of gas passage manifold 70. Thereafter, the gas or gas mixture may be exhausted through a gas outlet connector 82.
  • a blood inlet manifold 60 is formed or mounted on one side of the shell 42 and a blood outlet manifold 62 is formed or mounted on the opposite side of shell 42.
  • a blood inlet connector 64 is positioned on blood inlet manifold 60 to facilitate passage of blood into the inlet manifold 60
  • a blood outlet connector 66 is positioned on blood outlet manifold 62 to facilitate passage of blood out of blood outlet manifold 62.
  • a blood inlet flow path within blood inlet manifold 60 is configured to divide the flow of incoming .blood into separate streams passing out of slots 67 formed in the inner face of the blood inlet manifold 60.
  • Slots 67 of blood inlet manifold 60 are positioned in correspondence and fluidic connection with the substantially hollow blood circulation gaps 86 formed on the innermost region of each groove or channel 50 such that blood passing out of slots 67 will initially flow into the circulation gaps 86, and will subsequently pass outwardly through the channels 50, flowing over the outer surface of the hollow fiber membranes 10 disposed within each channel 50, thereby passing a film of blood over the outer surfaces 14 of the membranes 10.
  • Such contact of the blood with the outer surfaces 14 of the hollow fiber membranes 10 allows the blood to receive oxygen, and to give off carbon dioxide, through the semipermeable walls of the membranes 10.
  • the resultant PC02 and P02 of the blood may be controlled by adjusting the gaseous content (i.e., Fi0 2 and FiC0 2 ) and pressure of the gas mixture being passed through the lumens 16 of the individual hollow fiber membranes 10. iii. Operation Of A Preferred Membrane Oxygenator Device Incorporating The Hollow Fiber Membranes
  • the blood inlet connector 64 of the device 40 is connected to a vein of the patient such that venous blood from the patient will enter the blood inlet manifold 60 through inlet connector 64.
  • the blood outlet flow connector 66 is connected to the arterial vasculature of the patient via tubing such that oxygenated blood flowing out of blood outflow connector 66 will be returned to the arterial circulation of the patient.
  • Appropriate pumping means such as peristaltic blood pumps or other blood pumping apparatus are utilized to facilitate the above- described flow of blood to and from the patient.
  • Source(s) of the prescribed oxygen-containing gas mixture (e.g., either pure oxygen or blends of oxygen with other suitable gases such as nitrogen) is connected to gas inlet connector 80 by way of tubing.
  • the prescribed oxygen-containing gas mixture enters gas inlet chamber 74 and passes through the lumen 16 of the individual hollow fiber membranes 10 disposed within the blood receiving grooves 50 of the device 40. After passing through the lumens 16 of the individual hollow fiber membranes 10, the used gas subsequently passes into gas outlet chamber 76 and is exhausted through gas outlet connector 82.
  • Apparatus for monitoring the concentration of oxygen or other gases may be connected to the flow path adjacent either the gas inlet connector 80 or the gas outlet connector 82 so as to provide for ongoing monitoring of the relative concentrations of oxygen or other gases passing into or out of the device 40.
  • pressure sensing means may be positioned at one or more points along the gas- mixture pathway to permit monitoring of the pressure of the gas-mixture within the device 40.
  • a device for providing a recirculating flow of temperature-controlled heat exchange liquid e.g., saline or water
  • a heat exchanger inlet connector 88 and a heat exchanger outlet connector 90 so as to provide a recirculating flow of temperature-controlled heat exchange medium through heat exchanger jacket flow path 58 and into contact with the inner surface of the surrounding bellows 44.
  • the temperature of the blood exiting the device 40 through blood outlet connector 66 may be monitored and the temperature of the heat exchange medium circulated through flow path 58 may be thermostatically or otherwise adjusted so as to maintain or control the temperature of the blood exiting the blood outflow connector 66 within a prescribed temperature range.
  • the efficiency and consistency with which the partial pressures of 0 2 and C0 2 within the blood may be controlled is dependent upon the maintenance of consistent prescribed spacer widths SW between the outer surfaces 14 of the individual hollow fiber membranes 10 such that the film thickness and surface area contacted by the blood flowing through the device 40 may be optimized and maintained in a consistent fashion.
  • the disposition of the spiral monofilamentous spacer members 12 about the outer surfaces 14 of the individual hollow fiber membranes 10 within each membrane packet 84 serves to hold the individual hollow fiber membranes 10 within each packet 84 a desired prescribed spacer width SW from one another, thereby making certain that the film thickness and amount of blood circulating into contact with the outer surfaces 14 of the hollow fiber membranes 10 is consistent and predictable, with minimal unit-to-unit variation.
  • the spiral or helical disposition or formation of the spacer members 12 on the outer surfaces 14 of the hollow fiber membranes 10 serves to direct the blood flow in a non- turbulent laminar flow path about the outer surfaces 14 of the individual hollow fiber membranes 10 without unnecessary damming, disruption or turbulence of the blood as may result in thrombogenic consequences.
  • the individual spacer members 12 are formed of non-wetting monofilamentous material, such spacer members 12 do not wet with blood and do not result in hang-up or holding of blood within the device 40, as may occur with multifilament, woven or yarn-type wettable spacer members.
  • the monofilamentous spacer member 12 may be spirally wrapped around the outer surface 14 of an elongate tubular hollow fiber membrane 10.
  • Such spiral wrapping of a separate monofilamentous spacer member 12 about the outer surface 14 of a tubular hollow fiber membrane 10 may be accomplished manually or by automated machinery.
  • One example of an automated fiber-wrapping machine which may be utilized to spirally wrap monofilamentous fibers around an elongate hollow fiber membrane is a power driven hollow cored pirn having a quantity of the monofilamentous fiber wrapped therearound.
  • the hollow fiber membrane is fed longitudinally through the center of the spinning pirn and the monofilamentous fiber is spun off of the pirn and onto the outer surface of the advancing hollow fiber membranes, such that the monofilamentous fiber become spirally wrapped about the outer surface of the hollow fiber membrane.
  • the monofilamentous spacer member 12 comprises a spiral rib formed on the outer surface 14 of a tubular hollow fiber membrane 10
  • such rib may be extruded as part of the body of the hollow fiber membrane 10 as shown in Figures 5a and 5b.
  • An extrusion die 100 usable to form a monofilamentous ribbed hollow fiber membrane lOd comprises a round inner core member 102 disposed within the hollow inner bore of a cylindrical outer member 104.
  • a recess 106 or recesses is/are formed in the luminal surface of the cylindrical outer core 104 such that the workpiece extruded by the die 100 will be in the form of a generally round hollow tube lOd having a single raised rib 12d formed on the outer surface thereof.
  • a rotational force may be applied to the outer die member 104 and/or the emerging workpiece so as to cause the rib 12d to become spiralled about the outer surface of the tubular hollow fiber membrane lOd.
  • the rate at which the outer die member 104 and/or workpiece are rotated, relative to the rate at which the extruded workpiece emerges from the die 100, will determine the tightness or pitch interval of the spiral rib 12d.
  • Figure 6 shows a schematic diagram of a continuous manufacturing process whereby a separate, hollow monofilamentous spacer member may be initially wrapped about the outer surface of an advancing hollow fiber membrane and whereby the spirally wrapped hollow fiber membrane may be subsequently wrapped or mounted onto the outer surface of a core member, such as the core of a membrane oxygenator device, in a continuous fashion.
  • a core member such as the core of a membrane oxygenator device
  • a length of monofilamentous spacer material 108 (i.e., monofilament line or thread) is initially wrapped about the outer surface of the pirn 106.
  • the monofilamentous spacer member 108 is unwound from the outer surface of the pirn 106 and correspondingly wrapped about the outer surface of the advancing hollow fiber membrane 100.
  • the spiral pitch interval P at which the monofilamentous spacer member 108 is wrapped about the outer surface of the advancing hollow fiber membrane 100 may be controlled and/or adjusted by controlling or varying the feed rate of the hollow fiber membrane 100.
  • the spirally wrapped hollow fiber membrane is subsequently advanced over rollers 110, 112 and wrapped about the outer surface of a core member 114, such as the inner core of a blood membrane oxygenator device, an example of which is the central bellows 44 of the heat exchanger/membrane oxygenator device 40 shown in Figures 3a-3d and 4-4c of this patent application.
  • a core member 114 such as the inner core of a blood membrane oxygenator device, an example of which is the central bellows 44 of the heat exchanger/membrane oxygenator device 40 shown in Figures 3a-3d and 4-4c of this patent application.
  • the spiral wrapping of the monofilamentous spacer member 108 about the outer surface of the hollow fiber membrane 100 and the subsequent deployment or wrapping of the spirally wrapped hollow fiber membrane 10 about the outer surface of the device core member 114 is accomplished in a continuous process, without the need for intervening handling or manipulation of the hollow fiber membrane 100.
  • two or three parallel spacer members or ribs 12 may be disposed on the outer surface 14 of a single hollow fiber membrane 10 without causing impairment of the desired flow characteristics described herein and/or the desired consistent spacing between the individual hollow fiber membranes 10 and their adjacent surfaces.

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Abstract

L'invention se rapporte à des membranes semi-perméables, fibreuses creuses et améliorées qui possèdent des éléments d'écartement monofilamenteux, disposés en spirale ou formés sur la surface externe de ces membranes, ainsi que des dispositifs extracorporels de traitement du sang comprenant ces membranes fibreuses creuses améliorées. L'invention se rapporte également à des procédés de fabrication des membranes fibreuses et creuses ainsi qu'à un procédé continu de fabrication d'un appareil de traitement du sang comprenant les membranes fibreuses et creuses.
EP95921440A 1994-06-10 1995-05-25 Ecartement par monofilaments de membranes fibreuses et creuses et dispositifs d'oxygenation du sang comprenant ces membranes Withdrawn EP0764045A1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
US25802994A 1994-06-10 1994-06-10
US258029 1994-06-10
PCT/US1995/006691 WO1995034373A1 (fr) 1994-06-10 1995-05-25 Ecartement par monofilaments de membranes fibreuses et creuses et dispositifs d'oxygenation du sang comprenant ces membranes

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EP0764045A1 true EP0764045A1 (fr) 1997-03-26

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EP95921440A Withdrawn EP0764045A1 (fr) 1994-06-10 1995-05-25 Ecartement par monofilaments de membranes fibreuses et creuses et dispositifs d'oxygenation du sang comprenant ces membranes

Country Status (4)

Country Link
EP (1) EP0764045A1 (fr)
JP (1) JPH10504228A (fr)
CA (1) CA2191438A1 (fr)
WO (1) WO1995034373A1 (fr)

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KR100711132B1 (ko) * 1999-10-27 2007-04-27 톰슨 라이센싱 광 스캐닝 디바이스

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JP2001334131A (ja) * 2000-05-25 2001-12-04 Nok Corp 中空糸膜及び中空糸膜の加工方法及び中空糸膜モジュール及び中空糸膜モジュールの使用方法及び中空糸膜モジュールの製造方法
KR100910844B1 (ko) * 2002-07-19 2009-08-06 주식회사 파라 모노-필라멘트를 포함하는 보강용 지지체를 가지는기체분리 및 수처리용 외압식 중공사막, 그 제조방법 및제조장치
DE102005028718A1 (de) 2005-06-20 2006-12-28 Carl Freudenberg Kg Hohlfaseranordnung
KR101330175B1 (ko) * 2011-12-08 2013-11-15 한국정수공업 주식회사 중공섬유 분리막 모듈
US9034083B2 (en) * 2012-04-10 2015-05-19 Vivonics, Inc. Array of hollow fibers and a system and method of manufacturing same
WO2019092105A1 (fr) 2017-11-09 2019-05-16 Frank Wiese Conditionnement de faisceau de membranes présentant des éléments d'écartement
EP3482817A1 (fr) 2017-11-09 2019-05-15 Frank Wiese Habillage de faisceaux de membranes pourvu d'éléments d'écartement
WO2021061955A1 (fr) * 2019-09-26 2021-04-01 Cardiacassist, Inc. Membrane de fibres d'oxygénateur à propriétés de surface modifiées
AU2020375272A1 (en) * 2019-10-30 2022-04-14 Toray Industries, Inc. Fluid-separation carbon membrane module
US20240024549A1 (en) * 2020-11-27 2024-01-25 Uniwersytet Slaski Blood oxygenator with an organic membrane
WO2022113020A1 (fr) * 2020-11-27 2022-06-02 Slaski Uniwersytet Medyczny Oxygénateur de sang avec membrane organique
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Also Published As

Publication number Publication date
WO1995034373A1 (fr) 1995-12-21
CA2191438A1 (fr) 1995-12-21
JPH10504228A (ja) 1998-04-28

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