Patent Application
20140274648
The present subject matter relates to an umbilicus for use in a fluid processing system and more particularly to connection of the umbilicus to individual flow tubing.
Whole blood is routinely separated into its various components, such as red blood cells, platelets, and plasma. In continuous blood processing systems, whole blood is drawn from a donor, the particular blood component or constituent is removed and collected, and the remaining blood constituents are returned to the donor. By thus removing only particular constituents, less time is needed for the donor's body to return to normal, and donations can be made at more frequent intervals than when whole blood is collected. This increases the overall supply of blood constituents, such as plasma and platelets, made available for health care.
Whole blood is typically separated into its constituents through centrifugation. This requires that the whole blood be passed through a centrifuge after it is withdrawn from, and before it is returned to, the donor. To avoid contamination, the blood is usually contained within a sealed, sterile fluid flow system during the entire centrifugation process. Typical blood processing systems thus include a permanent, reusable centrifuge assembly or “hardware” that spins and pumps the blood, and a disposable, sealed and sterile fluid processing or fluid circuit assembly that actually makes contact with the donor's blood. The centrifuge assembly engages and spins a portion of the fluid processing assembly (often called the centrifuge or separation chamber) during a collection procedure. The blood, however, makes actual contact only with the disposable fluid processing assembly, which is used only once and then discarded.
To avoid the need for rotating seals, and to preserve the sterile and sealed integrity of the fluid processing assembly, continuous blood processing systems often utilize centrifuges that operate on the “one-omega, two-omega” operating principle. This principle is disclosed in detail in U.S. Pat. No. 4,120,449 to Brown et al., which is hereby incorporated by reference, and enables centrifuges to spin a sealed, closed system without the need for rotating seals. Blood processing systems that make use of the principle typically include a fluid processing assembly that includes a plastic bag or molded chamber that is spun in the centrifuge and that is connected to the blood donor and to a stationary portion of the centrifuge assembly through an elongated member that may be made up of one or more plastic tubes. The elongated member is commonly referred to as an “umbilicus” and is typically arranged in a question mark (or upside-down question mark) configuration with both of its end portions coaxially aligned with the axis of rotation of the centrifuge. The centrifuge chamber is rotated at “two-omega” RPM and the umbilicus is orbited around the centrifuge chamber at “one-omega” RPM. In other words, one end of the umbilicus is stationary, the other end rotates at a two-omega speed with the centrifuge chamber to which it is attached, and the intermediate portion or midsection of the umbilicus orbits about the chamber at a one-omega speed. The effect is that the end of the umbilicus, which is opposite the bag or chamber and is connected to the donor via plastic tubing, does not twist up as the bag is spun. The sealed, sterile integrity of the fluid processing assembly is thus maintained without the need for rotating seals.
U.S. Pat. No. 5,996,634 to Dennehey et al., which is hereby incorporated herein by reference, discloses one such blood processing apparatus based on the “one-omega, two-omega” operating principle. In this apparatus, a disposable fluid processing assembly having an umbilicus and a processing chamber is mountable within a centrifuge assembly. One “fixed” end of the umbilicus is held rotationally stationary substantially over the axis of centrifugation. The other “free” end of the umbilicus joins the processing chamber and is free to rotate with the processing chamber around the axis of centrifugation. The mid-portion of the umbilicus is supported by a wing plate that orbits the mid-portion of the umbilicus around the axis of centrifugation at the one-omega speed. On account of having one “fixed” end and one “free” end, the umbilicus will “twist” about its own central axis as its mid-portion orbits around the processing chamber. The action of the umbilicus naturally “untwisting” itself will cause its “free” end (and, hence, the associated processing chamber) to spin at the average prescribed two-omega speed. This arrangement eliminates the need for complex gearing or belting arrangements to create a one-omega, two-omega drive relationship that was common in prior art devices. The umbilicus itself drives the processing chamber at a two-omega speed.
A typical umbilicus comprises a unitarily formed (generally by an extrusion process) main body defining a plurality of fluid-transmitting lumen. The body is formed of a material specially selected to perform the several required functions of the umbilicus, including being flexible enough to assume the proper orientation with regard to the centrifuge assembly, rigid enough to serve as a drive mechanism for rotating the processing chamber, and having a torsional stiffness leading to the aforementioned “untwisting” at the proper two-omega speed during fluid processing. A known material used in forming the umbilicus is the thermoplastic polyester elastomeric material sold by E.I. DuPont de Nemours & Company under the trademark Hytrel®. The Hytrel® material may also be used to form enlarged end blocks that are over-molded onto the ends of the umbilicus for being clamped into different portions of the centrifuge assembly, with one (the “zero omega end block”) being held in place with respect to the centrifuge assembly and the other (the “two omega end block”) allowed to rotate freely, as described above. Polyvinyl choloride (“PVC”) tubing connecting the umbilicus to the remainder of fluid circuit assembly is bonded to the end blocks.
While such a known umbilicus has proven suitable, it can be relatively expensive to manufacture, and the need remains for a relatively low-cost improved umbilicus.
There are several aspects of the present subject matter which may be embodied separately or together in the devices and systems described and claimed below. These aspects may be employed alone or in combination with other aspects of the subject matter described herein, and the description of these aspects together is not intended to preclude the use of these aspects separately or the claiming of such aspects separately or in different combinations as set forth in the claims appended hereto.
In one aspect, an umbilicus for use in an umbilicus-driven fluid processing system comprises an elongated umbilicus body including first and second ends, and defines at least one fluid-transmitting lumen extending between the first and second ends, a first end fitting defining an interior cavity and including an elongated bore communicating with the cavity, the first end of the umbilicus body extending into the bore and being fixedly attached to the fitting. The interior cavity of the first end fitting includes a flared portion, and an adapter including a tapered portion is received within the interior cavity of the first end fitting with the tapered portion received within the flared portion and has at least one port extension extending into the fluid transmitting lumen of the umbilicus body. The adapter includes a lumen extending through the port extension and communicating between the at least one umbilicus lumen and a tubing port defined in the adapter, and the adapter and end fitting including interfering surfaces to enhance torque resistance therebetween.
In accordance with another aspect, a method is provided for manufacturing an umbilicus for use in an umbilicus-driven fluid processing system. The method includes providing an elongated umbilicus body having first and second ends and defining at least one fluid-transmitting lumen extending therebetween, providing a first end fitting defining an interior cavity having a flared portion and a bore communicating with the inner cavity, inserting the first end of the umbilicus body within the bore and fixedly attaching the umbilicus to the first end fitting, and inserting an adapter including a tapered portion into the cavity with the tapered portion received within the flared portion of the interior cavity. The adapter has at least one port extension extending into the fluid transmitting lumen of the umbilicus body, and the adapter includes a lumen extending through the port extension and communicating between the at least one umbilicus lumen and a tubing port defined in the adapter. The adapter and end fitting include interfering surfaces to enhance torque resistance therebetween, and the method further includes connecting a separate tube to the tubing port of the adapter.
In accordance with yet another aspect, a pre-assembled disposable centrifugal processing fluid circuit is provided, including a centrifugal processing chamber for rotating within the centrifuge and an umbilicus communicating at a first end with the centrifuge chamber and being configured at a second end for securing to a non-rotating portion of a centrifuge. The umbilicus body includes at least one fluid-transmitting lumen extending between the first and second ends, a first end fitting defining an interior cavity and including an elongated bore communicating with the cavity, the first end of the umbilicus body extending into the bore and being fixedly attached to the fitting. The interior cavity of the first end fitting includes a flared portion, and an adapter including a tapered portion is received within the interior cavity of the first end fitting with the tapered portion received within the flared portion and has at least one port extension extending into the fluid transmitting lumen of the umbilicus body. The adapter includes a lumen extending through the port extension and communicating between the at least one umbilicus lumen and a tubing port defined in the adapter. The adapter and end fitting including interfering surfaces to enhance torque resistance therebetween.
The embodiments disclosed herein are for the purpose of providing the required description of the present subject matter. They are only exemplary, and may be embodied in various forms and in various combinations. Therefore, specific details disclosed herein are not to be interpreted as limiting the subject matter as defined in the accompanying claims.
The durable fluid processing system 10 is used in combination with a disposable processing set or fluid circuit 14, an example of which is shown in
The disposable set 14 includes a processing chamber 16 (
As illustrated, the centrifuge assembly 12 includes a wheeled cabinet 26 that can be easily rolled from place to place. A user-actuable processing controller 30 is provided which enables the operator to control various aspects of the blood processing procedure. A centrifuge rotor assembly 32 is provided behind a fold open door 34 that can be pulled open at the front of the cabinet 26 (
In use, the fold open door 34 is opened and the processing chamber 16 of the disposable set 14 is mounted in the centrifuge rotor assembly 32 (
Looking more closely at the centrifuge rotor assembly 32 (
Referring further to
The other end of the umbilicus 24 is defined by another anchor portion or end fitting 64 (referred to herein as the “zero-omega end fitting”) that is removably received in an upper umbilicus mount 66 positioned over the centrifuge chamber assembly 42 substantially in alignment with the axis of centrifugation 44. An over-center clamp 68 at the end of the upper umbilicus mount 66 clamps onto the zero-omega end fitting 64 to hold the adjacent section of the umbilicus 24 rotationally stationary and in collinear alignment with the axis of centrifugation 44.
As further illustrated in
To maintain balance as the yoke assembly 46 turns, an additional support or wing plate 74 extends from the yoke cross member 52 diametrically opposite the wing plate 72. A counterweight 76 sufficient to balance the mass of the bearing support 70 and umbilicus 24 is preferably carried on the lower end of the additional wing plate 74.
To reduce the risk of damage to the umbilicus 24 during fluid processing, an umbilicus bearing assembly 78 may surround it and be received within the bearing support 70, in a manner well known to those skilled in the art. Exemplary umbilicus bearing assemblies are described in U.S. Pat. Nos. 5,989,177 and 8,277,369 to West et al., which are hereby incorporated herein by reference.
In the illustrated embodiment, the umbilicus 24 includes an umbilicus body 80 extending between first and second ends 84 and 82, with an intermediate section or midsection 86 located therebetween.
The end fitting 60 is preferably of molded plastic construction, and may be made of any suitable material. For example, it may be made of a thermoplastic polyester elastomeric material, such as Hytrel brand material from DuPont, or may be made of polyvinyl chloride (PVC). As see in
As seen in
The end of the umbilicus body is preferably fixedly attached to the end fitting 60. Although that may be achieved in different ways, in the present disclosure the umbilicus is preferably bonded to the cylindrical extension 92. As one example, the umbilicus may be solvent bonded to the bore 100 in the extension 92 using a suitable solvent for the particular materials used in umbilicus and end fitting 60. For the materials disclosed herein, a solvent such as cyclohexane may be used. The large surface area between the bore 100 and the end of the umbilicus body 80 provides a particularly strong attachment between the umbilicus body and the end fitting that has substantial torsional strength to resist the torsional forces experienced by the umbilicus during centrifuge rotation. In accordance with the present disclosure, however, this strength between the umbilicus and end fitting is further enhanced by the configuration and attachment of the adapter 86 to the end fitting 60.
The adapter 86 is configured for insertion into the interior cavity 94 of the end fitting 60. It is also preferably of molded plastic construction and may be of any suitable material. One example of a suitable material is polyvinyl chloride. The adapter 86 has an upper portion 104 and a lower portion 106, each having a shape complementary to the upper and lower portions 96 and 98, respectively, of the cavity 94. As illustrated, the upper portion 104 is generally cylindrical and the lower portion 106 is generally tapered or flared. The adapter includes an axially extending port extension 108 for each lumen of the umbilicus and, as illustrated, has five port extensions. A separate fluid flow lumen 110 extends through each port extension and into a separate tubing port 112 for attachment to a separate individual flow tube such as PVC tubes 114 shown in
As best seen in
To further enhance torsional strength of the assembly, the adapter 86 and interior cavity 94 preferably have interfering surfaces that resist relative rotational movement between them. While these surfaces may take any suitable shape, preferably the cavity or the adapter has one or more raised axially extending spline and the other has axially extending slots for receiving the spline. As can been seen in
With the above described structure, individual tubes such as individual PVC tubes 114 that extend to the centrifuge processing chamber may be readily connected to the umbilicus by insertion and attachment into the tube ports 112 of the adapter 86. More specifically, as noted above, a preferred material for the adapter 86 is PVC, which can be readily solvent bonded to PVC tubing. It will thus be evident that the present subject matter provides a connection assembly with high pull strength, large torsional resistance and ease of assembly for connecting one or more individual tubes to a centrifuge umbilicus, and has particular application and benefit in making connection between multiple individual tubes and a multi-lumen umbilicus.
The foregoing assembly steps may be practiced in a different order and/or additional assembly steps may be practiced and/or additional or different components may be incorporated into the umbilicus 24 during the assembly process without departing from the scope of the present disclosure.
It will be understood that the embodiments described above are illustrative of some of the applications of the principles of the present subject matter. Numerous modifications may be made by those skilled in the art without departing from the spirit and scope of the claimed subject matter, including those combinations of features that are individually disclosed or claimed herein. For these reasons, the scope hereof is not limited to the above description but is as set forth in the following claims.
