US20080087601A1 - Separation Apparatus and Method - Google Patents

Abstract

A separation apparatus and method are employed using a separation channel for rotation about an axis. Such channel includes radially spaced apart inner and outer side wall portions and an end wall portion. An inlet conveys fluid into the channel. A barrier is located in the channel intermediate of the inner and outer side wall portions. A first flow path communicates between upstream and downstream sides of the barrier. A collection region may be located downstream of the barrier for communication with the first flow path. An outer side wall section of the channel may be positioned radially outward of an upstream section thereof. The barrier may join the outer side wall portion along a substantial portion of an axial length of the channel. First and second exit flow paths may allow communication with the channel either upstream or downstream of the barrier or both.

Description

RELATED APPLICATIONS
• This application claims the benefit of co-pending U.S. application Ser. No. 10/279,765 filed Oct. 24, 2002, and entitled “Blood Processing Systems and Methods for Collecting Plasma Free or Essentially Free of Cellular Blood Components,” and claims the benefit of U.S. Provisional Application Ser. No. 60/533,820, filed Dec. 31, 2003, both applications which are incorporated by reference herein.
BACKGROUND
• The present invention relates in general to apparatus and methods for separating biological fluids, such as blood or blood components or other fluids, into one or more components.
• The separation of biological fluid such as whole blood and blood components into its constituent components for various applications is well known. Many commercially available separation systems are based on principles of centrifugation, which separates the fluid components according to density. Various devices and systems are known that employ centrifugal separation of blood or blood components including the CS-3000®, Amicus® and ALYX® separators marketed by Baxter Healthcare Corporation of Deerfield, Ill., the Spectra® and Trima® separators by Gambro BCT of Lakewood, Colo., the AS104 from Fresenius Homecare of Redmond, Wash., and the V-50 and other models from Haemonetics Corporation of Braintree, Mass. Various centrifuge devices are also disclosed in U.S. Pat. No. 6,325,775, Published PCT Application Nos. PCT/US02/31317; PCT/US02/31319; PCT/US03/33311 and PCT/US03/07944, and U.S. Published Patent Applications 20020094927 and 20020077241. Each of these patent and patent applications are hereby incorporated by reference herein.
• Although centrifugal blood separator devices are thus well known, efforts continue to develop devices that are smaller, lighter, more portable, versatile and/or efficient in the separation and collection of one or more different components of blood or other biological fluids.
SUMMARY OF THE INVENTION
• The present invention includes apparatus and methods for separation of a biological fluid, such as whole blood, and optional collection of at least one of the fluid components.
• In accordance with one embodiment of the present invention, a separation channel is provided for rotation about an axis. The separation channel includes radially spaced apart inner and outer side wall portions and an end wall portion. The channel has an axial length relative to the axis. An inlet is provided to convey fluid into the channel and a barrier is located in the channel intermediate of the inner and outer side wall portions. The barrier includes both upstream and downstream sides and includes a first flow path which communicates between the upstream and downstream sides. The separation channel further includes a collection region which is located downstream of the barrier and in fluid communication with the first flow path. The collection region is defined at least in part by an end wall portion which is axially spaced from the end wall portion of the channel. Additionally, first and second openings communicate with the collection region so as to allow flow of one or more fluid components, such as blood components, from the collection region.
• In another embodiment of the invention, a section of an outer side wall portion of the channel is located in the vicinity of a barrier and is positioned radially outward of the outer side wall portion that is upstream of such section.
• In a further embodiment of the separation channel, a barrier extends to an outer side wall portion and joins the outer side wall portion along a substantial portion of the axial length of the channel. A first flow path allows fluid communication between the upstream and downstream sides of the barrier.
• In yet a further embodiment of the separation channel, a barrier may extend to a radial position which is inward of the radial location of an inner side wall portion.
• An additional embodiment of the separation channel includes a first flow path which communicates between the upstream and downstream sides of a barrier and further includes first and second exit flow paths. The first exit flow path communicates with the channel upstream of the barrier while a second exit flow path communicates with the channel downstream of the barrier. The first and second flow paths join at a location radially inward of an inner wall portion of the channel.
• In addition, another separation channel may provide that a plurality of exit openings from the channel are located downstream of a barrier. In this respect, the channel is free of an exit opening upstream of the barrier inasmuch as fluid components are not allowed to exit the channel at a location which is upstream of the barrier. A first fluid flow path allows communication between the upstream and downstream sides of the barrier but does not provide an exit flow path to outside of the channel.
• In a still further embodiment of the separation channel, a barrier wall extends to a radially outer side wall portion of the channel. A first flow path communicates between the upstream and downstream sides of the barrier and is spaced from one of the opposed end wall portions of the channel. The separation channel further includes a second flow path which communicates between the upstream and downstream sides of the barrier, which second flow path is defined by a surface of the other end wall portion.
• Although described later in terms of certain preferred embodiments, it should be understood that the separation channels of the present invention are not limited to the identical structures shown. For example, a separation channel may comprise a reusable platen, bowl or rotor into which a disposable flexible, rigid or semi-rigid liner is placed so that blood flows through the liner and does not contact the reusable portion. In such case, the configuration of the channel platen, bowl or rotor defines the shape of fluid flow path and the disposable liner assumes a corresponding shape during operation. Examples of such may be seen in the CS-3000®, Amicus® and Spectra® centrifugal separation systems. Alternatively, the separation channel may be entirely disposable. For example, the channel may be formed of rigid plastic having a pre-formed shape through which the blood or other biological fluid is processed. Of course, the channel could be entirely reusable, in which case it would need to be cleaned and possibly sterilized between uses—an inconvenient and time consuming procedure. It should be understood that the separation channel and methods described and claimed are intended to have a broad interpretation that includes all of the more specific structures, such as those mentioned above, in which it may find commercial application.
• The separation channels or chambers described herein may be used for a variety of biological fluid separation and collection procedures. By way of example and not limitation, one of such separation methods comprises the steps of introducing a first fluid, such as whole blood, which comprises at least first and second components, e.g., blood components, having generally different density into a centrifugal field and allowing an interface to form between at least portions of the first and second components. The method includes removing a second fluid from one side of the interface and a third fluid from the other side of the interface, combining at least a portion of the second fluid with the first or third fluid and reintroducing the combined fluids into the centrifugal field, and removing at least one of the second or third fluid from the centrifugal field.
• When the above method is applied to whole blood (first fluid), the second fluid may substantially comprise plasma and the third fluid may substantially comprise red cells. The combined second and first or third fluid may have a hematocrit which is approximately between 20 and 40 percent. The portion of the plasma which is removed from one side of the interface may include substantial numbers of platelets.
• In accordance with another method of the present invention, the method includes introducing a first fluid, such as whole blood, which comprises first and second components having generally different density into a centrifugal field; allowing an interface to form between at least portions of the first and second fluid components; decreasing the force of the centrifugal field (such as by reducing the rotational field of separation chamber containing the fluid); and removing the first fluid component from the centrifugal field after the force of the centrifugal field is decreased.
• Some or all of the above steps of this method may be repeated to enhance efficiency. For example, the step of removing the fluid component may be repeated so as to provide several collection cycles. The above method may have particular application in the collection of platelets from whole blood wherein the first fluid component comprises plasma which includes platelets.
• A further method of the present invention provides for forming and reforming of the interface between the fluid components of different density. This method includes the steps of introducing a first fluid, such as whole blood which has at least first and second components of generally different density; allowing an interface to form between at least portions of the first and second components, such as between plasma and red cells of whole blood; sequentially and repeatedly removing fluid from the centrifugal field from one side of the interface and allowing the interface to reform.
• When the method is applied to whole blood, the fluid which is removed from the centrifugal field comprises plasma and platelets. In particular, the fluid may comprise plasma which is rich in platelet concentration. The method may be performed so that the step of removing the fluid from one side of the interface is repeated at least two times.
• The method may further include moving the interface radially inward so that the interface itself is in proximity with an aperture or opening, through which the plasma or platelets are removed. Where the step of removing is performed at least twice, it is contemplated that the interface may be returned to its initial location prior to moving it to proximity with the aperture.
• An additional method of the present invention includes a method for processing whole blood, which may serve to reduce the amount of time that the donor or other human subject or blood source is connected to the blood separation device. The method includes connecting a blood source to a separation device; introducing blood into a centrifugal field created by the device; and allowing an interface to develop between at least two blood components. The method further includes: removing a first blood component from the centrifugal field from one side of the interface; removing a second blood component from the centrifugal field from the other side of the interface; storing at least one of the first and second blood components; returning, at least in part, the other of the first and second blood components to the blood source; and withdrawing additional blood from the blood source. After the additional blood has been drawn, the blood source is disconnected, and the steps of introducing the blood into the centrifugal field and removing the first and second blood components are repeated. The first and second blood components that have been removed from the centrifugal field may be stored for later use as desired.
BRIEF DESCRIPTION OF THE DRAWINGS
• FIG. 1 is a perspective view of a fluid processing system, ideally suited for blood processing, comprising a blood processing device (shown in a closed condition for transport and storage) and a disposable liquid and blood flow set, which interacts with the blood processing device to cause separation and collection of one or more blood components (shown packaged in a tray for transport and storage before use).
• FIG. 2 is a perspective view of the blood processing device shown inFIG. 1, shown in an opened condition for operation.
• FIG. 3 is a perspective view of the blood processing device shown inFIG. 2, with the centrifugal station open to receive a blood processing chamber and the pump and valve station open to receive a fluid pressure-actuated cassette.
• FIG. 4 is a perspective view of the blood processing device shown inFIG. 3, with the tray containing the disposable liquid and blood flow set positioned for loading the flow set on the device.
• FIGS. 5 and 6 are, respectively, right and left side perspective views of the blood processing device shown inFIG. 2 after the liquid and blood flow set has been loaded onto the device for use.
• FIG. 7 is a perspective view of the blood processing chamber and attached umbilicus that forms a part of the liquid and blood flow set shown inFIGS. 5 and 6.
• FIG. 8 is a perspective view of the interior of a first embodiment of the blood processing chamber of a type shown inFIG. 7, which may perform a red blood cell separation and collection procedure or other procedures using the device shown inFIGS. 5 and 6.
• FIG. 9 is a perspective view of the interior of the centrifuge station of the device shown inFIGS. 5 and 6, with the station door opened to receive a blood processing chamber of a type shown inFIG. 7.
• FIG. 10 is a perspective view of the interior of the centrifuge station shown inFIG. 9 after a blood processing chamber of a type shown inFIG. 7 has been loaded for use.
• FIG. 11 is a diagrammatic view of the interior of the blood processing chamber of a type shown inFIG. 7, showing the separation of whole blood into a red blood cell layer, a plasma layer, and an intermediate buffy coat layer, with the position of the layers shown during normal conditions.
• FIG. 12 is a diagrammatic view of the interior of the blood processing chamber of a type shown inFIG. 7, with the buffy coat layer having moved very close to the low-G wall, creating an over spill condition that sweeps buffy coat components into the plasma being collected.
• FIG. 13 is a diagrammatic view of the interior of the blood processing chamber of a type shown inFIG. 7, with the buffy coat layer having moved very close to the high-G wall, creating an under spill condition that leads to a reduction of the hematocrit of red blood being collected.
• FIG. 14 is a top perspective view of the interior of a second embodiment of the blood processing chamber of the type shown inFIG. 7, the interior of the chamber which may perform a plasma separation and collection procedure or other procedures using the device shown inFIGS. 5 and 6.
• FIG. 15 is a bottom perspective view of the blood processing chamber shown inFIG. 14.
• FIG. 16 is an enlarged side perspective view of an interior region in the blood processing chamber shown inFIG. 14, showing a barrier having a tapered surface that directs red blood cells from the separation zone in a path separate from plasma.
• FIG. 17 is an enlarged bottom perspective view of the region shown inFIG. 16, showing the path that red blood cells take as they are directed from the separation zone by the barrier.
• FIG. 18 is an enlarged top perspective view of the region shown inFIG. 16, showing the separate paths that red blood cells and plasma take as they are directed from the separation zone by the barrier.
• FIG. 19 is a perspective view of the interior of a third embodiment of the chamber of a type shown inFIG. 7, the interior of the chamber which may be used to perform a fluid separation and collection procedure using the device shown inFIGS. 5 and 6, with a partial view of one of the opposed end wall portions being shown spaced from the remaining portion of the chamber.
• FIG. 20 is a top view of the interior of the chamber ofFIG. 19.
• FIG. 20A is an enlarged partial top view of a collection region of the chamber ofFIG. 20.
• FIG. 21 is a bottom perspective view of the chamber ofFIG. 19.
• FIG. 22 is a perspective view of the chamber ofFIG. 19 with a portion of the chamber shown in section.
• FIG. 23 is a perspective view of the interior of a fourth embodiment of the chamber of a type shown inFIG. 7 with the top end wall portion shown removed, which chamber may be used to perform a fluid separation and collection procedure using the device shown inFIGS. 5 and 6.
• FIG. 24 is a partial top view of the chamber ofFIG. 23.
• FIG. 23A is a perspective view of a fifth embodiment of the chamber which is similar to the chamber ofFIG. 23 except that the chamber ofFIG. 23A lacks any exits paths from the channel upstream of the barrier.
• FIG. 24A is a perspective view of the fluid flow of the chamber shown inFIG. 23A, with the chamber removed, so as to show the path of the fluid inside the chamber.
• FIG. 25 is a sixth embodiment of the chamber of the type shown inFIG. 7, the interior of the chamber being configured to perform a platelet separation and collection procedure using the device shown inFIGS. 5 and 6.
• FIG. 26 is a top view of the interior of the chamber shown inFIG. 25.
• FIG. 27 is a partial perspective view of the chamber ofFIG. 25 with portions of the chamber shown in section.
• FIG. 28 is a perspective view of the interior of a seventh embodiment of the chamber of the type shown inFIG. 7, the interior of the chamber being configured to perform a fluid separation in a collection procedure using the device shown inFIGS. 5 and 6
• FIG. 29 is a partial top view of the chamber ofFIG. 28.
• FIG. 30 is a partial perspective view of the chamber ofFIG. 28 with portions of the chamber being shown in section.
• FIG. 31 is a top view of the interior of an eighth embodiment of the chamber of the type shown inFIG. 7, the interior of the chamber being configured to perform various fluid separation and collection procedures using the device shown inFIGS. 5 and 6.
• FIG. 32 is an enlarged partial left perspective view of the chamber ofFIG. 31.
• FIG. 33 is an enlarged partial top view of the encircled portion of the chamber ofFIG. 31.
• FIG. 34 is an enlarged partial top perspective view of the chamber ofFIG. 31 with portions of the chamber shown in section.
• FIG. 35 is a top view of the interior of a ninth embodiment of the chamber of the type shown inFIG. 7, which is configured to perform various fluid separation and collection procedures using the device shown inFIGS. 5 and 6.
• FIG. 36 is an enlarged partial perspective view of the chamber ofFIG. 35 with a portion of the outer side wall portion being shown removed.
• FIG. 37 is an enlarged partial top view of the chamber ofFIG. 35.
• FIG. 38 is a further enlarged top view of a portion of the chamber shown inFIG. 37.
• FIG. 39 is a perspective view of the interior of a tenth embodiment of the chamber of the type shown inFIG. 7, which is configured to perform a fluid separation and collection procedure using the device shown inFIGS. 5 and 6.
• FIG. 40 is a top view of the chamber ofFIG. 39.
• FIG. 40A is an enlarged top view of the chamber ofFIG. 39.
• FIG. 41 is a perspective view of the fluid flow within the chamber shown inFIG. 39, with the chamber removed, so as to show the path of the fluid inside the chamber.
• FIG. 42A is a partial sectional view along theline42A-42A ofFIG. 40.
• FIG. 42B is a partial sectional view along theline42B-42B ofFIG. 40.
• FIGS. 43-45 are schematic views of a fluid circuit that can be implemented in accordance with one of the fluid collection methods described herein.
• FIG. 45A is a graphical representation of the recirculation rate (in ml/min) versus the platelet concentration in a sample collected radially inward of the red blood cell and plasma interface which has been collected after a predetermined period of recirculation.
• FIG. 45B is a graphical representation of the recirculation rate (in ml/min) versus the white blood cell count a sample collected radially inward of the red blood cell and plasma interface which has been collected after a predetermined period of recirculation.
• FIG. 45C shows a graphical representation of both platelet and white blood cell concentrations observed during various times during recirculation.
• FIG. 46 is a diagrammatic view of the interior of the chamber of the type shown inFIG. 7, showing separation of whole blood in accordance with another method which includes the step of decreasing the centrifugal force to expand at least one of the separation layers.
• FIGS. 47 and 48 are schematic views of a fluid circuit that can be implemented in accordance with another method described herein.
• FIG. 49 is a chart illustrating the collection and return cycles of at least a portion of a fluid component relative to a blood source in accordance with one of the methods described herein.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
• FIG. 1 shows aliquid processing system10 that embodies the features of the invention. Thesystem10 can be used for processing various fluids. The system101sparticularly well suited for processing whole blood and other suspensions of biological cellular materials. Accordingly, the illustrated embodiment shows thesystem10 used for this purpose.
I. System Overview
• Thesystem10 includes two principal components. These are: (i) ablood processing device14—shown inFIG. 1 in a closed condition for transport and storage, and inFIGS. 2 and 3 in an opened condition for operation; and (ii) a liquid and blood flow set12, which interacts with theblood processing device14 to cause separation and collection of one or more blood components—theset12 being shown inFIGS. 1 and 4 packaged in atray48 for transport and storage before use, and inFIGS. 5 and 6 removed from thetray48 and mounted on theblood processing device14 for use. Although portions of thesystem10 will be described further, details of the system are described in one or more of the above-identified patents or patent applications which have been incorporated by reference herein.
• A. The Processing Device
• Theblood processing device14 is intended to be a durable item capable of long term use. In the illustrated and preferred embodiment, theblood processing device14 is mounted inside a portable housing orcase36. Thecase36 presents a compact footprint, suited for set up and operation upon a table top or other relatively small surface. Thecase36 is also intended to be transported easily to a collection site.
• Thecase36 includes abase38 and a hingedlid40, which closes for transport (asFIG. 1 shows) and which opens for use (as FIGS.2 to4 show). In use, thebase38 is intended to rest in a generally horizontal support surface. Thecase36 can be formed into a desired configuration, e.g., by molding. Thecase36 is preferably made from a lightweight, yet durable, plastic material.
• Acontroller16 is carried onboard thedevice14. Thecontroller16 governs the interaction between the components of thedevice14 and the components of the flow set12 to perform a blood processing and collection procedure selected by the operator. In the illustrated embodiment, thecontroller16 comprises a main processing unit (MPU), which can comprise, e.g., a Pentium® type microprocessor made by Intel Corporation, although other types of conventional microprocessors can be used. The MPU can be mounted inside thelid40 of thecase36. A power supply withpower cord184 supplies electrical power to the MPU and other components of thedevice14.
• Preferably, thecontroller16 also includes aninteractive user interface42, which allows the operator to view and comprehend information regarding the operation of thesystem10. In the illustrated embodiment, theinterface42 is implemented on an interface screen carried in thelid40, which displays information for viewing by the operator in alpha-numeric format and as graphical images.
• Further details of thecontroller16 can be found in Nayak et al, U.S. Pat. No. 6,261,065, which is incorporated herein by reference. Further details of the interface can be found in Lyle et al, U.S. Pat. No. 5,581,687, which is also incorporated herein by reference.
• AsFIG. 1 shown, thelid40 can be used to support other input/outputs to couple other external devices to thecontroller16 or other components of thedevice14. For example, anEthernet port50, or aninput52 for a bar code reader or the like (for scanning information into the controller16), or adiagnostic port54, or a port56 to be coupled to apressure cuff60 worn by a donor to enhance blood flow rates during blood processing (see, e.g.,FIGS. 43-45 and47-48), or a systemtransducer calibration port58, can all be conveniently mounted for access on the exterior of thelid40, or elsewhere on thecase36 of thedevice14.
• B. The Flow Set
• The flow set12, is intended to be sterile, single use, disposable item. Before beginning a given blood processing and collection procedure, the operator loads various components of the flow set12 in association with the device145 (asFIGS. 4 and 5 show). Thecontroller16 implements the procedure based upon preset protocols, taking into account other input form the operator. Upon completing the procedure, the operator removes the flow set12 from association with thedevice14. The portion of theset12 holding the collected blood component or components are removed from thedevice14 and retained for storage, transfusion, or further processing. The remainder of theset12 is removed from thedevice14 and discarded.
• The flow set includes ablood processing chamber18, a fluid actuated pump andvalve cassette28, and an array associatedprocessing containers64 and flow tubing coupled to thechamber18 and thecassette28. Several embodiments of thechamber18 will be identified in greater detail below.
• 1. The Blood Processing Chamber
• In the illustrated embodiment (seeFIG. 5), the flow set12 includes ablood processing chamber18 designed for use in association with a centrifuge. Theprocessing device14 includes a centrifuge station20 (seeFIGS. 2 and 3, which receives theprocessing chamber18 for use (seeFIG. 5).
• AsFIGS. 2 and 3 show, thecentrifuge station20 comprises acompartment24 formed in thebase38. Thecentrifuge station20 includes adoor22. Thedoor22 opens (asFIGS. 3 and 5 show) to allow loading of theprocessing chamber18 into thecompartment24. Thedoor22 closes (asFIGS. 2 and 6 show) to enclose theprocessing chamber18 within thecompartment24 during operation.
• Thecentrifuge station20 rotates theprocessing chamber18. When rotated, theprocessing chamber18 centrifugally separates a fluid, preferably whole blood which is received from a donor into component parts, principally, red blood cells, plasma, and intermediate layer called the buffy coat, which is populated by platelets and leukocytes. As will be described later, the configuration of thechamber18 can vary according to the intended blood separation objectives. Several embodiments of thechamber18 will be described below.
• 2. The Fluid Pressure-Actuated Cassette
• In the illustrated embodiment, theset12 also includes a fluid pressure-actuated cassette28 (seeFIG. 5). Thecassette28 provides a centralized, programmable, integrated platform for all the pumping and valving functions required for a given blood processing procedure. In the illustrated embodiment, the fluid pressure comprises positive and negative pneumatic pressure, although other types of fluid pressure can be used.
• AsFIG. 5 shows, thecassette28 is mounted for use in a pneumatic actuated pump andvalve station30, which is located in the lid of the40 of thecase36. The pump andvalve station30 includes adoor32 that is hinged to move between an opened position, exposing the pump and valve station30 (seeFIG. 3) for loading and unloading thecassette28, and a closed position, enclosing thecassette28 within the pump andvalve station30 for use (shown inFIG. 6). The pump andvalve station30 includes a manifold assembly34 (seeFIG. 4) located behind a valve face gasket when thecassette28 is when mounted on the pump andvalve station30. The pneumatic pressures direct liquid flow through thecassette28.
• 3. Blood Processing Containers and Tubing
• Referred back toFIGS. 5 and 6, the flow set16 also includes an array of tubes and containers in flow communication with thecassette28 and thechamber18. The arrangement of tubes and containers can vary according to the processing objectives. Representative blood processing procedures and the associated flow sets accommodating such procedures will be described later.
• Anumbilicus100 forms a part of the flow set16. When installed, theumbilicus100 links the rotatingprocessing chamber18 with thecassette28 without need for rotating seals. Theumbilicus100 can be made from rotational-stress-resistant plastic materials, such as Hytrel® copolyester elastomers (DuPont).
• Referring now toFIG. 7,tubes102,104, and106 extend from the proximal end of theumbilicus100. Thetube102 conveys whole blood into theprocessing chamber18 for separation. Thetubes104 and106 convey, respectively, centrifugally separated red blood cells and plasma from theprocessing chamber18. The plasma can either be rich or poor in platelets, depending upon the processing objectives.
• AsFIG. 7 shows, afixture108 gathers thetubes102,104, and106 adjacent theumbilicus100 in a compact, organized, side-by-side array outside thecentrifuge station20. Thefixture108 allows thetubes102,104 and106 to be placed and removed as a group in association with an optical sensing station46 (seeFIGS. 9 and 10), which is located adjacent to thecentrifuge station20 outside thechamber18.
• Theoptical sensing station46 optically monitors the presence or absence of targeted blood components (e.g., red blood cells and platelets) in blood conveyed by thetubes104 and106. Thesensing station46 provides outputs reflecting the presence or absence of such blood components. This output is conveyed to thecontroller16. Thecontroller16 processes the output and generates signals to control processing events based, in part, upon the optically sensed events. Further details of the operation of the controller to control processing events based upon optical sensing have been described in one or more of the above-identified patent or applications, which have been incorporated herein by reference.
• As shown (seeFIGS. 5 and 6), the flow set16 includes aphlebotomy needle128, through which a door can be coupled to thesystem10 for blood processing. InFIGS. 5 and 6, the flow set16 also includes ablood sampling assembly110. Theblood sampling assembly110 allows for the collection of one or more samples of the donor's blood at the commencement of a given blood processing procedure, through thephlebotomy needle128. A conventional manual clamp114 (e.g., a Roberts Clamp) is provided to control blood flow into thesampling assembly110.
• As also shown inFIGS. 5 and 6, the flow set16 can include an in-line injection site112. Theinjection site112 allows a technician to introduce saline or another physiologic liquid or medication into the donor, if necessary, using thephlebotomy needle128, and without requiring an additional needle stick. An additional in-linemanual clam116 is desirably included upstream of theblood sampling assembly110 and theinjection site112. The flow set16 may include an appropriate junction such as a T-site, Y-site, V-site or other connector arrangement.
• The device further includes one ormore weigh stations62 and other forms of support for containers. The arrangement of these components on the de-vice14 can, or course, vary depending on the processing objectives. By way of example and not limitation,FIGS. 5 and 6show collection containers158,160,162 and172 for in-process (or whole blood), plasma, red blood cells, and leuko-reduced red, cells respectively. InFIGS. 5 and 6 other reservoirs orcontainers150,164 and168 may contain various other fluids for use during the procedure such as, and not limited to anticoagulant, saline and a preservative or storage solution. As blood or liquids are received into and/or dispensed from the containers during processing, theweight stations62 provide output reflecting weight changes over time. This output is conveyed to thecontroller16. Thecontroller16 processes the incremental weight changes to derive fluid processing volumes. The controller generates signals to control processing events based, in part, upon the derived processing volumes.
• C. The Centrifuge Station
• The centrifuge station20 (seeFIG. 9) includes acentrifuge assembly68. Thecentrifuge assembly68 is constructed to receive and support the moldedprocessing chamber18 andumbilicus100 for use.
• As illustrated inFIG. 9, thecentrifuge assembly68 includes a frame oryoke70 having bottom, top, andside walls72,74,76. Theyoke70 spins on a bearing element78 (FIG. 9) attached to thebottom wall72. Anelectric drive motor80 is coupled to thebottom wall72 of theyoke70, to rotate theyoke70 about anaxis82. In the illustrated embodiment, theaxis82 is essentially horizontal (seeFIG. 3), although other angular orientations can be used. Themotor80 is capable of rotating theyoke70 in either clockwise or counterclockwise directions, depending upon commands issued by thecontroller16.
• A carrier orrotor plate84 spins within theyoke70 about itsown bearing element86, which is attached to thetop wall74 of theyoke70. Therotor plate84 spins about an axis that is generally aligned with the axis ofrotation82 of theyoke70.
• AsFIG. 7 shows, the top of theprocessing chamber18 includes anannular lip220, to which thelid component202 is secured. AsFIG. 10 show, therotor plate84 includes a latchingassembly88 that removably grips thelip220, the secure theprocessing chamber18 on therotor plate84 for rotation. Details of the latchingassembly88 can be found in one or more of the above-identified patents or patent applications which have been incorporated herein by reference.
• AsFIG. 10 shows, asheath144 on the near end of theumbilicus100 fits into a preformed, recessedpocket90 in thecentrifuge station20. Thepocket90 holds the near end of theumbilicus100 in a non-rotating stationary position aligned with the mutually alignedrotational axes82 of theyoke70 androtor plate84. Thetubes102,104, and106 are placed and removed as a group in association with thesensing station46, which is also located within thepocket90, asFIG. 10 shows.
• Umbilicus drive orsupport members92 and94 andchannels96 and98 (seeFIGS. 9 and 10) receive portions of theumbilicus100. The relative rotation of theyoke70 at a one omega rotational speed and therotor plate84 at a two omega rotational speed, keeps theumbilicus100 untwisted, avoiding the need for rotating seals. Further details of this arrangement are disclosed in Brown et al. U.S. Pat. No. 4,120,449, which is incorporated herein by reference and in one or more of the above-identified patents or patent applications which have been incorporated by reference herein.
• D. Interface Control by Optical Sensing
• In any of the above-described blood processing procedures, the centrifugal forces present within theprocessing chamber18 separate whole blood into a region of packed red blood cells and a region of plasma (as diagrammatically shown inFIG. 11). The centrifugal forces cause the region of packed red blood cells to congregate along the outside of radially outer or high-G wall of the chamber, while the region of plasma is transported to the radially inner or low-G wall of the chamber.
• An intermediate region forms an interface between the red blood cell region and the plasma region. Intermediate density cellular blood species like platelets and leukocytes populate the interface, arranged according to density, with the platelets closer to the plasma layer than the leukocytes. The interface is also called the “buffy coat,” because of its cloud color, compared to the straw color of the plasma region and the red color of the red blood cell region.
• It may be desirable to monitor the location of the buffy coat, either to keep the buffy coat materials out the plasma or out of the red blood cells, depending on the procedure, or to collect the cellular contents of the buffy coat. For that purpose, the system includes theoptical sensing station46, which houses two optical sensing assemblies is, also diagrammatically shown inFIGS. 11, 12 and13.
• Thefirst sensing assembly146 in thestation46 optically monitors the passage of blood components through theplasma collection tube106. Thesecond sensing assembly148 in thestation46 optically monitors the passage of blood components through the red bloodcell collection tube104.
• Thetubes104 and106 are made from plastic (e.g. polyvinylchloride) material that is transparent to the optical energy used for sensing, at least in the region where thetubes104 and106 are to be placed into association with thesensing station46. Thefixture108 holds thetubes104 and106 in viewing alignment with isrespective sensing assembly148 and146. Thefixture108 also holds thetube102, which conveys whole blood into thecentrifuge station20, even though no associated sensor is provided. Thefixture108 serves to gather and hold alltubes102,104, and106 that are coupled to theumbilicus100 in a compact and easily handled bundle.
• Thefirst sensing assembly146 is capable of detecting the presence of optically targeted cellular species or components in theplasma collection tube106. The components that are optically targeted for detection vary depending upon the procedure.
• The presence of platelets in the plasma, as detected by thefirst sensing assembly146, indicates that the interface is close enough to the low-G wall of the processing chamber to allow all or some of these components to be swept into the plasma collection line (seeFIG. 12). This condition will also be called an “over spill.”
• Thesecond sensing assembly148 is capable of detecting the hematocrit of the red blood cells in the red bloodcell collection tube104. The decrease of red blood hematocrit below a set minimum level during processing indicates that the interface is close enough to the high-G wall of the processing chamber to allow all or some of the components in the interface and perhaps plasma on the other side of the interface to enter the red blood cell collection tube104 (seeFIG. 13). This condition will also be called an “under spill.”
II. Embodiments of the Blood Processing Chamber
• Several embodiments of the chamber are described herein. These chambers may be used with the flow set12 in association with thedevice14 andcontroller16 to conduct various collection procedures.
A. First Embodiment of the Blood Processing Chamber
• FIG. 8 shows an embodiment of thecentrifugal processing chamber198, which can be used in association with thesystem10 shown inFIG. 1 to perform a double unit red blood cell collection procedure as well as other procedures. Theprocessing chamber198 is fabricated in two separately molded pieces; namely, thebase201 and thelid202. Thehub204 is surrounded radially by inside and outsideannular walls206 and208 that define a circumferentialblood separation channel210. A molded annular wall214 (seeFIG. 7) closes the bottom of thechannel210. Thelid202 is secured to the top of thechamber200, e.g., by use of a cylindrical sonic welding horn.
• The insideannular wall206 is open between one pair of stiffening walls which form an openinterior region222 in thehub204. Blood and fluids are introduced from theumbilicus100 into and out of theseparation channel210 through thisregion222. A moldedinterior wall224 formed inside theregion222 extends entirely across thechannel210, joining the outsideannular wall208. Thewall224 forms a terminus in theseparation channel210, which interrupts flow circumferentially along thechannel210 during separation.
• Additional molded interior walls divide theregion222 into threepassages226,228, and230. Thepassages226,228, and230 extend from thehub204 and communicate with thechannel210 on opposite sides of theterminus wall224. Blood and other fluids are directed from thehub204 into and out of thechannel210 through thesepassages226,228, and230.
• As theprocessing chamber198 shown inFIG. 8 is rotated (arrow R inFIG. 8), theumbilicus100 conveys whole blood into thechannel210 throughpassage226. The whole blood flows in thechannel210 in the same direction as rotation (which is counterclockwise inFIG. 8). Alternatively, thechamber198 can be rotated in a direction opposite to the circumferential flow of the whole blood, i.e., clockwise, although a whole blood flow in the same direction as rotation is believed to be desirable for blood separation efficiencies.
• The whole blood separates as a result of centrifugal forces in the manner shown inFIG. 11. Red blood cells are driven toward the radially outer high-G wall208, while lighter plasma constituent is displace toward the radially under low-G wall206.
• AsFIG. 8 shows, adam244 projects into thechannel210 toward the high-G wall208. The dam orbarrier244 prevents passage of plasma, while allowing passage of red blood cells into achannel246 recessed in the high-G wall208. Thechannel246 directs the red blood cells into theumbilicus100 through theradial passage230. The plasma constituent is conveyed from thechannel210 through theradial passage228 intoumbilicus100.
• Because the red bloodcell exit channel246 extends outside the high-g wall208, being spaced further from the rotational axis than the high-g wall, the red bloodcell exit channel246 allows the positioning of the interface between the red blood cells and the buffy coat very close to the high-g wall208 during blood processing, without spilling the buffy coat into the red blood cell collection passage230 (creating an spill under condition). The recessedexit channel246 thereby permits red blood cells yields to be maximized (in a red blood cell collection procedure) or an essentially platelet-free plasma to be collected (in a plasma collection procedure).
B. Second Embodiment of the Blood Processing Chamber
• FIG. 14 shows an embodiment of thecentrifugal processing chamber200, which can be used in association with thesystem10 shownFIG. 1 such as to perform a plasma collection procedure, yielding plasma that is free or essentially free of platelets, red blood cells, and leukocytes. Thechamber200 shown inFIG. 14 can also be used to perform a combined plasma/red blood cell collection procedure, which collects plasma and concentrated red cells separately, as well as other procedures such as platelet collection, which collects a concentrated platelet and plasma mixture.
• As previously described with respect to embodiment of a chamber shown inFIG. 8 (with like parts being assigned like reference numerals), theprocessing chamber200 is desirably fabricated as separately moldedbase component201 and alid component202, although other configurations may be employed for this and the other processing chamber embodiments as discussed above in the summary of the invention, without departing from the broader aspects of the present invention. The moldedhub204 is surrounded radially by inside and outsideside wall portions206 and208 that define a generally circumferentialblood separation channel210. A molded wall214 (seeFIG. 15) forms an end wall portion of thechannel210. Thelid component202 forms another end wall portion of thechannel210 and may also be comprised of an insert242. While both opposed end wall portions are shown to be generally flat (i.e., normal to the rotational axis) and theside wall portions206 and208 are shown as generally cylindrical, it should be appreciated that the boundaries can be tapered, rounded, V-shape, and the like. When assembled, thelid component202 is secured to the top of thechamber200, e.g., by use of a cylindrical sonic welding horn.
• In thechamber200 shown inFIG. 14, the innerside wall portion206 is open between one pair of stiffening walls. The opposing stiffening walls from an openinterior region222 in thehub204, which communicates with thechannel210. Blood and fluids are introduced from theumbilicus100 into and out of theseparation channel210 through thisregion222.
• In the embodiment shown inFIG. 14, a moldedinterior wall224 is formed inside theregion222 that extends entirely across thechannel210, joining the outerside wall portion208. Thewall224 forms terminus in theseparation channel210, which interrupts flow circumferentially along thechannel210 during separation.
• Additional molded interior walls divide theregion222 into threepassages226,228 and230. Thepassages226,228 and230 extend from thehub204 and communicate with thechannel210 opposite sides of theterminus wall224. Blood and other fluids are directed from thehub204 into and out of thechannel210 through thesepassages226,228 and230.
• As theprocessing chamber200 is rotated (arrow R inFIG. 14), an umbilicus100 (not shown) conveys whole blood to thepassage226 which leads tochannel210. The whole blood flows in thechannel210 in the same direction as rotation (which is counterclockwise inFIG. 14). Alternatively, thechamber200 can be rotated in a direction opposite to the circumferential flow of whole blood, i.e., clockwise, although whole blood flow is the same direction as rotation is believed desirable for optimal blood separation.
• The whole blood separates within thechamber200 as a result of centrifugal forces in the manner showing inFIG. 11. Red blood cells are driven toward the outer side wall portion or high-G wall208, while lighter plasma constituent is displaced toward the low-G wall206. The buffy coat layer resides between the inner and outerside wall portions206 and208.
• Circumferentially spaced adjacent theterminus wall224 nearly 360-degrees from the wholeblood inlet passage226 are theplasma collection passage228 and the red bloodcell collection passage230. In an upstream flow direction from thesecollection passages228 and230, abarrier232 projects into thechannel210 from the high-G wall208. Thebarrier232 forms a constriction in theseparation channel210 along the inner side wall portion or low-G wall206. In the circumferential flow direction of the blood, the constriction leads to theplasma collection passage228.
• AsFIGS. 16 and 17 show, aleading edge234 of thebarrier232 is tapered toward an annular boundary of the channel210 (which, in the illustrated embodiment, is the annular wall214) in the direction toward theterminus wall224. Thetapered edge234 of thebarrier232 leads to anopening236, which faces the annular boundary of theseparation channel210. Theopening236 faces but is spaced axially away from the annular boundary closely adjacent to the high-G wall208. Theopening236 communicates with the red bloodcell collection passage230.
• Aledge238 extends an axial distance within theopening236 radially from the low-G wall206. Theledge238 constricts the radial dimension of theopening236 along the radially outer or high-G wall208. Due to theledge238, only red blood cells and other higher density components adjacent to the high-G wall208 communicate with theopening236. Theledge238 keeps plasma, which is not adjacent the high-G wall208, away from communication with theopening236. Due to the radial restrictedopening236 along the high-G wall208, the plasma has nowhere to flow except toward theplasma collection passage228. The plasma exiting theseparation channel210 is thereby free or essentially free of the higher density materials, which exit theseparation channel210 through the restricted high-G opening236.
• Theledge238 joins anaxial surface240, which is generally aligned with the low-G wall206. Theaxial surface240 extends axially along the axis of rotation to the red bloodcell collection passage230. By virtue of thebarrier232, theledge238, and other interior walls, the red bloodcell collection passage230 is isolated from the plasma collection passage228 (asFIG. 18 shows).
• AsFIG. 18 also best shows, plasma residing along the low-G wall206 is circumferentially directed by thebarrier232 andledge238 to theplasma collection passage228 and into theumbilicus100. The higher density fluid, contain red blood cells and may also contain the buffy coat components (platelets and leukocytes) depending on the procedure employed. Such higher density fluid resides closer to the high-G wall208 and is directed axially along the taperededge234 of thebarrier232 toward an annular boundary and the restricted high-G opening236. From the high-G opening236, the red blood cells and buffy coat components comprising the higher density fluid are directed over theradial ledge238 toward the low-G wall206, and axially into the red bloodcell collection passage230 and into theumbilicus100.
C. Third Embodiment of the Blood Processing Chamber
• InFIGS. 19-22, the processing chamber is generally indicated at300. Thechamber300 may be used in association with thesystem10 shown inFIG. 1 to perform various collection procedures for various biological fluids, including, but not exclusively, for blood. Thechamber300 may be used to perform a platelet or platelet rich plasma (PRP) collection procedure—which collects a concentrated platelet and plasma mixture—, a combined red blood cell and plasma collection procedure—which collects plasma and concentrated red cells separately—, and a combined red blood cell and platelet collection procedure—which procedure collects concentrated red blood cells and concentrated platelets separately—, as well as other procedures.
• Thechamber300 includes a separately moldedbase component301 having ahub304 that is disposed along an axis A of the chamber. Thebase301 of thechamber300 includes radially spaced inner (low-g) and outer (high-g)side wall portions306 and308, respectively. The side walls are consistently referred to in this description as the radially inner (or low-g) wall and the radially outer (or high-g) wall. The inner and outerside wall portions306 and308 and opposedend wall portions302 and314 generally define a circumferential (which is not limited to circular)blood separation channel310. A firstend wall portion314 forms one axial boundary or bottom to thechannel310 and a second end wall portion or lid302 (partially shown inFIG. 19) generally forms the other axial boundary or top of thechannel310.
• Although the inner andouter wall portions306 and308 are shown as substantially circumferential, i.e., as generally vertical walls having a generally uniform radius relative to a common axis A, other orientations, shapes, axes and radii are also possible. Also, while the top and bottom end wall portions are shown to be generally planar, it is also possible that these end wall portions could have other shapes such as curved, arcuate and the like. The shape and orientation of the channel also may depend on whether the channel is formed of flexible, semi-rigid, or rigid structures. It should also be appreciated that the designation of the end wall portions as “top” or “bottom” are not meant to limit these structures. Such terms are meant to be arbitrary and are merely used to distinguish one end wall from the other end wall in the relationship shown in the drawings in order to facilitate understanding of these structures.
• As shown inFIGS. 20 and 20A, the upstream end of thechannel310 includes a pair of opposing interiorradial walls322 and324. The interiorradial wall324 joins the outerside wall portion308 and generally separates thechannel310 between its upstream and downstream ends. Theinterior walls322 and324 extend radially outward from thehub304 to define aninlet passageway326 for a fluid, preferably whole blood, to enter thechamber300. Theinlet passageway326 is generally defined at or near the top of thechamber300, as shown inFIG. 22, and preferably is formed in part by a surface of the topend wall portion302. Theinlet326 includes anopening325 which is preferably disposed at a radial location which is adjacent the outer or high-gside wall portion308 and whichopening325 is defined by a surface thereof. A step or edge323 of the interiorradial wall322 is disposed radially intermediate the inner and outerside wall portions306 and308 and also preferably defines a surface of theopening325 through which fluid is directed into thechannel310.
• At the downstream end of thechannel310, first, second and thirdexit flow paths328,330 and332 may define outlet paths for one or more fluid components from thechannel310. A dam orbarrier336 is also located at the downstream end of thechannel310 and will be described in further detail below.
• InFIG. 20A, the firstexit flow path328 is defined between thebarrier328 and an interiorradial wall335 which extends radially outward from thehub304. Radially inward of thebarrier328, from ajunction352, the first flow path is defined between two interiorradial walls334 and335. The firstexit flow path328 includes anopening327 through which fluid enters from thechannel310.Such opening327 is preferably located upstream of thebarrier336 at a radial location which is approximate to the radial location of the innerside wall portion306.
• When thechannel310 is operating under normal conditions—i.e., not under spill or over spill conditions—fluid in thefirst flow path328 preferably flows either radially inward of the junction352 (and outside of the chamber300) or, alternatively, travels radial outward at thejunction352 into the secondexit flow path330. By “normal conditions”, it is meant that the blood components in thechannel310 are separated into plasma, buffy coat and red blood cells and are preferably disposed in the relative radial locations, as shown inFIG. 11. Normal conditions may also include where the blood components in thechannel310 are separated into platelet rich plasma and red blood cells and the interface between the plasma and red blood cells is disposed radially intermediate the inner (low-g) and outer (high-g) wall, similar to the radial location of the interface shown inFIG. 11.
• InFIG. 20A, the secondexit flow path330 is defined generally downstream of the firstexit flow path328 and, between thebarrier336 and the interiorradial wall334. The secondexit flow path330 may allow fluid communication downstream of thebarrier336 between the first and thirdexit flow paths328 and332. The secondexit flow path330 includes afirst opening329 which is preferably adjacent thejunction352 to fluidly communicate with thefirst exit flow328 path although other locations are also possible. Asecond opening331 of the secondexit flow path330 is preferably radially outward of thefirst opening329.
• Under normal conditions, the direction of the fluid flow (e.g. plasma flow) in the secondexit flow path330 is generally such that fluid flows radial inward of thejunction352 towards theopening331. The extent of the radial path traversed by the plasma in the secondexit flow path330 will depend on the radial location of the interface between the plasma and red blood cells. Preferably, plasma flows into the secondexit flow path330 from the firstexit flow path328 to fill the secondexit flow path330 radially inward of the interface but does not flow radially outward of the interface. Under normal conditions, the plasma from the firstexit flow path328 will predominantly flow out of thechamber300 with some plasma flowing into the secondexit flow path330 to fill the area radially inward of the interface.
• Although the preferred flow pattern of the first and secondexit flow paths328 and330 is discussed above, it is also possible that the fluid within the first and second exit flow paths may follow a different flow pattern. This flow pattern may depend on the position of the interface associated with one or more fluid components and the rate at which one or more fluid components are collected from thechannel310 as well as other factors. By way of example, and not limitation, if the interface between the plasma and red blood cells is moved radially inward to force an over spill condition, then the fluid in the secondexit flow path330 may flow radially outward through theopening329 at thejunction352.
• InFIG. 20A, the thirdexit flow path332 is defined between the interiorradial walls334 and324 and includes anopening333.Such opening333 is preferably located downstream of thebarrier336 and downstream of the first and secondexit flow paths328 and330. Fluid may enter theopening333 into the thirdexit flow path332 for removal from thechannel310.
• As shown inFIGS. 20, 20A and22, thebarrier336 includes anupstream side338 and adownstream side340 each of which are generally perpendicular to the outerside wall portion308. Thebarrier336 extends radially across thechannel310 generally between the radial locations which correspond to the inner and outerside wall portion306 and308. InFIG. 20A, the barrier preferably is disposed radially inward of the inner (low-g)side wall portion306 and tapers along anangled wall342 to thejunction352. Thebarrier340 also includes a taper or curve near to or adjacent the outerside wall portion308. Although the barrier is shown having a shape which tapers near the inner and outerside wall portions306 and308, this shape is shown by way of example and not limitation and it is realized that other shapes are also possible.
• As shown inFIG. 22, theupstream side338 of thebarrier336 extends axially from theend wall portion302 at the top of thechannel310 along a substantial portion of the axial length of thechannel310. At theupstream side338, the axial location of thebarrier336 terminates at a location which is preferably spaced from theend wall portion314. At such axial location, afirst flow path344 allows communication between the upstream anddownstream sides338 and340 of thebarrier336. Thefirst flow path344 is preferably located at an intermediate axial location between the opposedend wall portions302 and314. InFIG. 22, thefirst flow path344 is shown closer to theend portion314 and, more particularly, is shown at an axial location which is approximately located at the bottom half or third of thechamber300. InFIG. 22, fluid entering through theinlet326 and traveling to thefirst flow path344 must traverse a substantial axial extent of thechannel310. Other intermediate axial locations of thefirst flow path344 are also possible, such as intermediate locations along thebarrier336. It is also possible that thefirst flow path344 may be located at an axial location which is near to or adjacent the bottomend wall portion314 of thechannel310.
• InFIGS. 20 and 20A, thefirst flow path344 is defined along its outer radial surface by one or more of first and second radiallyoutward sections309 and311 of the outerside wall portion308. Thefirst section309 tapers radially outwardly from a radial location of a more upstream section of the outerside wall portion308. Thefirst section309 is generally located upstream of thebarrier336 and joins asecond section311 downstream of thebarrier336. Suchsecond section311 is also radially outward as compared to the radial location of the outerside wall portion308 at a more upstream location of thechannel310—i.e. upstream of thesection309. Thesecond section311 is preferably disposed at the same radial location as thefirst section311. An opposed inner radial surface of thefirst flow path344 is preferably disposed at a radial location which is approximate to the radial location of the more upstream section of the outerside wall portion308.
• InFIGS. 20 and 20A, a collection region, generally defined at346, is disposed downstream of the barrier336 (shown in broken lines). A top surface of thecollection region346 is defined by theend wall portion302 at the top of thechannel310. Thecollection region346 also includes an intermediate end wall portion348 (FIG. 22) which defines at least a portion of the bottom surface of thecollection region346. The intermediateend wall portion348 is axially spaced from theend wall portions302 and314 at the top and bottom of thechannel310. Although the intermediateend wall portion348 is shown generally parallel to theend wall portion314 of thechannel310, other orientations are also possible.
• InFIG. 20A, thecollection region346 is also defined, in part, by thedownstream side340 of thebarrier336 and theinterior wall324 of thechannel310. Also, inFIG. 20A, thecollection region346 is generally disposed between the radial locations corresponding to the inner and outerside wall portions306 and308 and preferably is defined between the radial locations of the innerside wall portion306 and thesection311 of the outerside wall portion308.
• As best seen inFIG. 22, thecollection region346 includes an axially directed opening347 formed in the intermediateend wall portion348. Fluid travels axially upwards from thefirst flow path344 along thedownstream side340 of thebarrier336 to enter the bottom of thecollection region346 through theopening347. As previously described, theopenings331 and333 (as best seen inFIG. 20A) may also allow fluid communication of one or more fluid components into or out of thecollection region346. InFIG. 20A, thecollection region346 includes a radiallyoutward edge350 of the interiorradial wall334 which is positioned between theopenings331 and333 to the second and thirdexit flow paths330 and332.Such edge350 is disposed at an intermediate radial location between the innerside wall portions306 and the radiallyoutward section311 of the outer (high-g)wall portion308. The radial location of theedge350 is preferably positioned closer to the radial location of thesection311.Such edge350 is preferably positioned so that during normal conditions the higher density fluid such as red blood cells may exit the thirdexit flow path332 and so that the lower density fluid does not exit therethrough.
• During use, a fluid, such as whole blood, enters theinlet326 and flows into thechannel310. As the fluid first enters thechannel310, the fluid is generally located at the top of thechannel310. The axial extent of fluid flow at theopening325 of theinlet passageway326 may be initially confined at its lower axial extent at the inlet by a bottom floor354 (as seen inFIG. 22). The axial location of thefloor354 may be disposed at an axial location which is approximate to that of the intermediateend wall portion348 of thecollection region346 although other axial locations are also possible. After the fluid enters thechannel310, the channel is preferably no longer constrained at its lower axial extent, although it is still constrained at its upper axial extent by the opposedend wall portion302.
• In thechannel310, the fluid may essentially follow a spiral pattern (shown in broken lines inFIG. 22) as it travels downstream so that the fluid generally increases in its axial extent although other patterns are also possible. Upstream of thebarrier336, the axial extent of the fluid is preferably disposed from the topend wall portion302 at the top of thechannel310 to at least the approximate axial location of thefirst flow path344 or lower. By utilizing as much volume within the channel, it is believed that more efficient separation of the fluid components is obtained.
• As the blood flows downstream, centrifugal force allows the components of the blood to separate radially according to density within thechannel310. Further details of this separation are set forth in Brown, “The Physics of Continuous Flow Centrifugal Sell Separation,” Artificial Organ, 13(1):4-20 (1989).
• FIG. 11 shows one example of the relative radial locations of the blood components upstream of thebarrier336 during normal conditions of thechannel310. Plasma is primarily disposed towards the inner or low-gside wall portion306, and the red blood cells are primarily disposed towards the outer or high-gside wall portion308. Platelets and leukocytes, also known as the “buffy coat”, are primarily disposed at an interface between the plasma and red blood cells and are located at intermediate radial location. For a platelet collection procedure, further processing steps are preferably performed, as described in further detail below, to suspend at least a portion of the platelets in the plasma so as to form platelet rich plasma on one side of the interface between platelet rich plasma and red blood cells.
• Upstream of thebarrier336, at least one fluid component may be collected through the firstexit flow path328. Such component may include platelet poor plasma PPP or platelet rich plasma PRP. Such component also may flow into the secondexit flow path330 at thejunction352. Another fluid component, preferably, red blood cells, may flow into thefirst flow path344 for removal through the thirdexit flow path332. If the platelets are primarily located in the buffy coat, at least a substantial portion of the buffy coat is sequestered at theupstream side338 of thebarrier336. In this regard, thebarrier336 may allow accumulation of platelets upstream of thebarrier336 at a certain point during the procedure, for example, where platelet poor plasma PPP is being removed from thechannel310. Such procedures will be discussed in further detail below. Thus, the portion of the interface between the plasma and red blood cells downstream of thebarrier336 preferably contains substantially less or virtually no platelets as compared to the interface located between these components upstream of thebarrier336.
• Downstream of thebarrier336, the interface is allowed to form between the red blood cells and plasma which may also be either platelet rich or platelet poor plasma. Under normal conditions, the interface between the plasma and red blood cells is located at an intermediate radial location—i.e. between the inner andouter wall portions306 and308—. Such interface is preferably located radially inward of thefirst flow path344 so that primarily red blood cells flow through thefirst flow path344 during normal conditions. More preferably, the interface between the red blood cells and plasma is disposed at a radial location which is approximate to theedge350. Such radial location allows the red blood cells to be collected from one side of the interface into the thirdexit flow path332 but allows substantially little or no flow of plasma from the other side of the interface into the thirdexit flow path332. Plasma and red blood cells primarily flow through the first and thirdexit flow paths328 and332, respectively. Thesecond flow path330 preferably contains plasma or platelet rich plasma radially inward of the interface and red blood cells radially outward of the interface. Some flow of plasma or red blood cells may occur in the secondexit flow path330, depending on the radial location of the interface, but such flow preferably does not change such location of the interface.
• Other flow patterns are possible and may depend on other radial positions of the interface. For example, during an over spill condition, —i.e., where red blood cells flow out of the channel through the firstexit flow path328 with the plasma or platelets—, the interface moves radially inward and the secondexit flow path330 may allow red blood cells to flow from thecollection region346 out of thechannel310. During an under spill condition, —i.e., where plasma or platelets flow out of the channel through the thirdexit flow path332 with red blood cells—the interface moves radially outward and the secondexit flow path330 may allow some plasma or platelets from the firstexit flow path328 to flow into the thirdexit flow path332.
D. Fourth Embodiment of the Blood Processing Chamber
• FIGS. 23 and 24 illustrate a chamber generally indicated at360 which is identical to thechamber300 ofFIGS. 19-22 (with all identical parts being identified with identical numbers and shall not be described further) except for certain modifications which will be described further below. As compared to the embodiment ofFIGS. 19-22,FIGS. 23-24 show that theopening325 of theinlet326 is disposed at a radial location which is approximate to the outerside wall portion308. The blood thus is allowed to enter thechannel310 at a location which is tangential to the outer (high-g)wall portion308. Such location may aid in the separation of the blood component and/or may avoid back flow of blood components if the flow rate through theinlet326 is slowed or stopped.
• Theinlet326 is defined by a radially outward portion309C of the outerside wall portion308. Theedge323 of theinterior wall322 is radially spaced from the portion309C and is disposed at a radial location which is approximate to the radial location of the outerside wall portion308 at a more downstream section of thewall portion308. Fluid flowing through theinlet326 follows a path along theinterior wall322 to a location which is radially outward of theedge323 and then enters thechannel310 through theopening325.
E. Fifth Embodiment of the Blood Processing Chamber
• FIGS. 23A and 24A show achamber360A, or the fluid flow within such chamber, which chamber is similar to thechamber360 ofFIGS. 23 and 24, and, as such, identical numerals will be used to describe identical parts, followed by the letter ‘A’ and will not be described further.
• As compared to the embodiment ofFIGS. 23 and 24, thefirst flow path344A ofFIGS. 23A and 24A is disposed at an axial location which is adjacent theend wall portion314A at the bottom of thechamber360A. Thefirst flow path344A may be defined by a surface of theend wall portion314A. In this regard, fluid flowing into thefirst flow path344A must increase in its axial extent essentially to the bottom of thechannel310A. At the downstream side of thebarrier336A, the fluid travels from the bottom of thechannel310A in an axial direction towards the top of the channel to enter thecollection region346A through theopening347A. As shown inFIG. 24A, the fluid occupies a substantial portion of the volume of thechannel310A between the firstend wall portion314A at the bottom of thechannel310A and the second end wall portion (not shown) at the top of the channel.
• Also as compared to the embodiment ofFIGS. 23 and 24, thechannel310A ofFIGS. 23A and 24A lacks an opening to anexit flow path328A at a location which is upstream of the barrier. InFIGS. 23A and 24A, anopening327A into the firstexit flow path328A is located in thechannel310A at a location which is either at or slightly downstream of theupstream side338A of thebarrier336A. As previously described, plasma, either rich or poor in platelets, enters theopening327A and may flow radially inward of thejunction352 to exit thechannel310A or, alternatively, flow into the secondexit flow path330A. Afirst flow path344A allows fluid communication between the upstream anddownstream sides338A and340A of thebarrier336A but does not form an exit flow path to the outside of thechannel310A. Red blood cells flowing through thefirst flow path344A preferably exit thechannel310A through a thirdexit flow path332A downstream of thebarrier336A.
F. Sixth Embodiment of the Blood Processing Chamber
• FIGS. 25-27 illustrate a further embodiment of a chamber, which is generally indicated at370 having radially spaced apart inner (low-g) and outer (high-g)side wall portions372 and374, respectively, and a first and second end walls (only a firstend wall portion376 being shown). Thewall portions372,374 and376 together define achannel378.
• Aninlet379 is defined between opposing interiorradial walls377 and381. One of theinterior walls377 joins the outer (high-g) wall portion and separates the upstream and downstream ends of thechannel378. Similar to the embodiment ofFIG. 19-22, the interior walls define theinlet passageway379 of thechamber370 which allow fluid to enter the upstream end of thechannel378 at a location which is adjacent the outer or high-gside wall portion374. A dam orbarrier380 is formed at a downstream end of thechannel378 and has upstream anddownstream sides382 and384 and extends from the outerside wall portion374 radially inward to a location which is spaced from the innerside wall portion372. Thebarrier380 will be described in further detail below.
• InFIGS. 26-27, a first flow path386 (FIG. 26) communicates between the upstream and thedownstream sides382 and384 of thebarrier380. InFIG. 27, thefirst flow path386 is located at an intermediate axial position spaced above thebottom end wall376 and spaced below the top end wall (not shown). Similar to the embodiments ofFIGS. 18-24,sections373 and375 (FIG. 26) of the outerside wall portion374 just upstream and downstream of thebarrier382 extend radially outward from a more upstream section of the outerside wall portion374. An outer radial surface of thefirst flow path386 is preferably formed in part by one or more of these radiallyoutward sections373 and375 of the outer side wall portion374 (whichsections373 and375 are shown removed inFIG. 27). An opposed inner radial surface of thefirst flow path386 is preferably formed at a radial location which is approximate to that of the outer or high-G wall portion374.
• A second flow path, generally indicated at388, also communicates between the upstream anddownstream sides382 and384 of thebarrier380. As shown inFIG. 27, anopening400 of thesecond flow path388 preferably allows fluid to flow into the second flow path from a more upstream location of thechannel378. Thesecond flow path388 is preferably defined by a surface of the second end wall portion (not shown) which is generally placed over the top of the chamber shown in FIGS.25-27. An intermediateend wall portion398 defines the lower axial surface of thesecond flow path388 and will be described in further detail below. As shown inFIGS. 26 and 27, thesecond flow path388 includes both non-radial andradial portions387 and381, respectively. Thenon-radial portion387 is preferably defined by the space between the innerside wall portion372 and a radially inward surface of thebarrier380. Theradial portion389 is defined by thedownstream side384 of thebarrier380 and an interiorradial wall extension404. The interiorradial wall extension404 terminates at anouter edge405 which is located at an intermediate radial location between the inner and outerside wall portions372 and374.
• Thechamber370 further includes first and secondexit flow paths390 and392, respectively, which are defined by opposing surfaces of interior radial walls. The firstexit flow path390 is located upstream of thebarrier380. The secondexit flow path392 is located downstream of thebarrier380. Both first and secondexit flow paths390 and392 extend radially inward from thechannel378. The firstexit flow path390 extends radially inward from anopening391 which is preferably located at the innerside wall portion372. The secondexit flow path392 extends radially inward from anopening396.Such opening396 communicates with acollection region394, which region is located downstream of thebarrier380 and extends to the interiorradial wall377. Preferably, the firstexit flow path390 is disposed at approximately a 45 degree angle from the secondexit flow path392, although other angles and orientations are also possible.
• InFIGS. 26 and 27, thecollection region394 is defined at least in part, at its lower boundary by theend wall portion398 which is spaced above the firstend wall portion376 of thechannel378. The top of thecollection region394 is preferably defined by the end wall portion (not shown) at the top of thechannel378. Thecollection region394 is also generally defined between thesection375 of the outerside wall portion374 and the innerside wall portion372. Fluid may enter thecollection region394 through thefirst flow path386 and may also enter through thesecond flow path388, depending on the location of the interface between the plasma and red blood cells. The fluid from thecollection region394 may exit through theoutlet396 into thesecond exit path392 for removal from thechannel378.
• FIG. 26 shows the relative positions of plasma P and red blood cells RBC during normal conditions where the interface is located radially intermediate the inner (low-g) and outer (high-g)wall portions372 and374. Plasma or platelet rich plasma is preferably collected through theopening391 in firstexit flow path390 upstream of thebarrier380. Further downstream, a portion of the plasma is also permitted to flow into theopening400 and through at least a portion of thesecond flow path388. The extent of such plasma flow into thesecond flow path388 will depend on the location of the interface between the plasma and red blood cells. For example, the interface between the plasma and red blood cells is preferably located at or near theedge405 of the interiorradial wall extension404 during normal conditions. During such conditions, plasma flowing into thesecond flow path388 will preferably remain radially inward of theedge405 until further processing steps are performed to move the interface and allow collection thereof. Red blood cells RBC are permitted to flow through thefirst flow path386 into thecollection region394, and exit thechannel378 through theoutlet396 of the secondexit flow path392.
G. Seventh Embodiment of the Blood Processing Chamber
• FIGS. 28-30 illustrate a further embodiment of the blood processing chamber, generally indicated at410. Similar to previous embodiments, thechamber410 has radially spaced apart inner and outerside wall portions412 and414, respectively, and anend wall portion416 at the bottom of thechamber410 opposite an end wall portion (not shown) at the top of thechamber410. Together the inner and outerside wall portions412 and414 and the end wall portions define achannel418.
• InFIG. 29, radially directedinterior walls420 and422 define aninlet424 which communicates with thechannel418. Theinterior wall422 extends fully to the outerside wall portion414 to separate the upstream and downstream ends of thechannel418. Similar to the embodiments ofFIGS. 23-24, anopening425 of theinlet passageway424 is disposed at a radial location which is tangential to the radial location of the outerside wall portion414. Preferably, theinterior wall420 terminates at anedge443 which is radially spaced from a radiallyoutward wall section413 of the outerside wall portion414 so as to direct fluid into thechannel418.Such edge443 may be located at a radial location approximate to that of the outer (or high-G)wall portion414.
• InFIG. 29, abarrier426 is generally located at the downstream end of thechannel418 and includes upstream anddownstream sides428 and430, respectively, and radially inner andouter edges432 and434, respectively. InFIGS. 29 and 30, thebarrier426 joins the inner and outerside wall portions412 and414 along a substantial axial extent of the channel. As shown inFIG. 30, thebarrier426 preferably joins the inner and outerside wall portions412 and414 along an axial extent from an intermediateend wall portion460 to theend wall portion416 at the bottom of thechannel418.
• Above the intermediateend wall portion460, the inner and outer radial edges of thebarrier426 are not joined so as to allow flow around thebarrier426. As shown inFIG. 30, the radiallyinner edge432 is spaced from the innerside wall portion412 along an axial extent from the top of thechannel418 to the intermediateend wall portion460. Theinner edge432, in part, defines anexit opening448 from thechannel418 through a firstexit flow path446. The outerradial edge434 of thebarrier426 is spaced from a pocket orsection415 of the outerside wall portion414.Such section415 is positioned radially outward of the outerside wall portion414 which is upstream of such section. Afirst flow path440 is defined betweensuch edge434 andsuch section415 and extends from the top end wall portion (not shown) to the intermediateend wall portion460. The radial location of the outerradial edge434 of thebarrier426 is preferably approximate to the radial location of the outerside wall portion414 at such upstream location. Below the intermediateend wall portion460, the inner andouter edges432 and434 of thebarrier426 extend fully between theside wall portions412 and414 and/or thesection415 without any spacing therebetween, as best seen inFIG. 30. Therefore, as shown inFIG. 30, thebarrier426 joins the inner and outerside wall portions412 and414 along a substantial portion of the length of thechannel418.
• As shown inFIG. 29, thebarrier426 also includes a radially inward ortail portion436. Thetail portion436 extends radially inward of the innerside wall portion412 and terminates at ajunction438. Thetail portion436 and interiorradial walls442,444, and422 define a plurality ofexit paths446,450 and454 as shown. InFIG. 29, first and secondexit flow paths446 and450 fluidly communicate with each other at thejunction438. Preferably, none of the openings to theexit paths446,450 and454 shown inFIGS. 28-30 are located at a position which is upstream of thebarrier426.
• Theopening448 to the firstexit flow path446 as previously described, is defined between theinner edge432 of thebarrier426 and the innerside wall portion412.Such opening448 is defined in part by thebarrier426 and thus, is not located upstream of the barrier. A secondexit flow path450 is located further downstream of the firstexit flow path446 and also lacks any openings upstream of thebarrier426.Openings451 and453 of the secondexit flow path450 generally allow communication between the first and thirdexit flow paths446 and454 andsuch openings451 and453 are located downstream of thebarrier426. As previously discussed, plasma may flow from the firstexit flow path446 into the secondexit flow path450 depending on the radial location of the interface. A thirdexit flow path454 is located downstream of the first andsecond flow paths450 and452 and includesopening456 which preferably allows removal of red blood cells from thechannel418. Thefirst flow path440 allows communication between the upstream and downstream sides of thebarrier426 but also does not allow fluid to exit thechannel418 upstream of thebarrier426. Thus, thechannel418 lacks any opening to remove fluid from the channel upstream of thebarrier418.
• Thechannel418 further includes a collection region458 (shown in broken lines inFIGS. 29 and 30) downstream of thebarrier426. Thecollection region458 is generally defined between the top of thechannel418 and the intermediateend wall portion460. Thecollection region458 also is generally defined between radial locations corresponding to theinner wall portion412 and thesection415 of theouter wall portion414. As is contemplated by the various embodiments discussed herein, the size and location of thecollection region458 may vary depending on the particular chamber design. Similar to embodiments discussed above, thefirst flow path440 and the second and thirdexit flow paths450 and454—throughopenings453 and456—allow communication with thecollection region458.
• Plasma or platelet rich plasma is collected radially inward of the interface between plasma and red blood cells. Such plasma is preferably is permitted to flow through theopening448 into the firstexit flow path446 and out of thechannel418. Radially outward of the interface, red blood cells are permitted to flow through thefirst flow path440 into thecollection region458 and exit through the thirdexit flow path454. The secondexit flow path450 may contain either plasma or red blood cells, or both, depending on the location of the interface between the plasma and red blood cells. During normal conditions, the interface is preferably maintained between the radial locations of theouter edge443 and theinner edge432 of thebarrier426. For such condition, the secondexit flow path450 may primarily allow flow of plasma above such location of the interface although other flow patterns are possible.
H. Eighth Embodiment of the Blood Processing Chamber
• FIGS. 31-34 illustrate a yet further embodiment of the blood processing chamber, generally indicated at410A. Thechamber410A is similar to thechamber410 discussed inFIGS. 28-30 and as such, similar parts will be shown with the same number followed by the designation of letter ‘A’. As compared to the embodiment ofFIGS. 28-30, thechamber410A ofFIGS. 31-34 includes abarrier426A, which barrier is not formed with a tail portion, as inFIGS. 28-30. Instead, a separate intermediateradially extending wall436A is spaced downstream of thebarrier426A and forms a portion of one or more exit flow paths.
• As with the embodiment ofFIGS. 28-30, thechamber410A ofFIGS. 31-34 includes radially spaced inner and outerside wall portions412A and414A and opposed end wall portions, a firstend wall portion426A being shown inFIG. 34. Thesewall portions412A,414A and416A together define achannel418A. Opposedinterior walls420A and422A define aninlet424A.
• Similar to the embodiment ofFIGS. 28-30, an opening orpassageway448A inFIGS. 33 and 34 is defined between theinner edge432A of thebarrier426A and the innerside wall portion412A. As compared to the embodiment ofFIGS. 28-30,such opening448A inFIGS. 31-34 communicates with a firstexit flow path446A but does not form the opening to the firstexit flow path446A. Instead, the firstexit flow path446A is disposed downstream of thebarrier426A and extends radially inward from anopening449A which is formed in the innerside wall portion412A at a location which is downstream of thebarrier426A. A portion of the firstexit flow path446A is defined between the intermediateradially extending wall436A and an interiorradial wall444A.
• At a radially inward location shown inFIG. 32, theintermediate wall436A terminates at ajunction438A. Radially inward of thejunction438A, the firstexit flow path446A is defined between theinterior walls442A and444A. At thejunction438A, fluid from the firstexit flow path446A may flow radially outward into the secondexit flow path450A or radially inwardly through the first exit flow path for removal from thechannel418A.
• InFIGS. 32-34, the secondexit flow path450A is defined downstream of thebarrier426A between an interiorradial wall442A and the intermediateradially extending wall436A, and includes openings451A (FIG. 32) and453A (FIG. 34). As previously described, the secondexit flow path450A generally allows fluid communication between, the first and thirdexit flow paths446A and454A although the actual flow will depend on the radial location of the interface. The thirdexit flow path454A is defined downstream of thebarrier426A between the interiorradial walls442A and422A and includes anopening456A. Thus, as shown inFIGS. 32-34, each of theexit flow paths446A,450A and454A and its corresponding openings are located in the channel downstream of thebarrier426A.
• InFIGS. 32-34, acollection region458A is generally defined downstream of thebarrier426A between an intermediateend wall portion460A and the top end wall (not shown) of thechannel418A, and is further generally defined between the innerside wall portion412A and a radiallyouter portion415A of the outerside wall portion414A. Afirst flow path440A communicates between the upstream and thedownstream sides428A and430A of thebarrier426A and is in fluid communication with thecollection region456A. Downstream of thebarrier426A, one or more of theopenings449A,453A and456A may communicate with thecollection region458A depending on the radial location of the interface.
• As best seen inFIGS. 33 and 34rthe intermediateradially extending wall436A terminates at a radiallyoutward edge439A. The radiallyoutward edge439A is located in thecollection region458A at a radial location which is radially intermediate the inner and outerside walls portions412A and414A. A radiallyoutward edge443A of the adjacentinterior wall442A also extends into thecollection region458A and is located an intermediate radial location, which location is preferably radially outward of the radial location of theother edge439A. During normal conditions, the interface is preferably located between the radial locations of theedges439A and443A. Plasma or platelet rich plasma radially above the interface preferably is allowed to flow into the firstexit flow path446A—and may flow in either a radially inward or radially outward direction at thejunction438A. Red blood cells radially outward the interface are preferably allowed to flow into the thirdexit flow path454A and exit thechannel418A.
I. Ninth Embodiment of the Blood Processing Chamber
• Turning toFIGS. 35-38, an additional embodiment of the chamber, generally indicated at410B, is shown. Thechamber410B is similar to theprevious chambers410 and410A as described inFIGS. 31-34 and as such, corresponding alpha numeric references which include the letter ‘B’ will be used to describe thechamber410B. As compared to the embodiments ofFIGS. 31-34, the outerside wall portion414B of thechamber410B ofFIGS. 35-38 does not include a radially outward section or pocket.
• As previously described, afirst flow path440B and apassageway448A allow communication between the upstream and downstream sides of thebarrier426B. Afirst flow path440B is defined in an axial direction between an outerradial edge434B of abarrier426B and the outerside wall portion414B and extends in a radial direction from the top end wall (not shown) of thechannel418B to an intermediateend wall portion460B. An opening orpassageway448B is defined in a radial direction between the innerside wall portion412B and the innerradial edge432B of thebarrier426B and is defined in an axial direction between the top of the channel to the intermediateend wall portion460B. Below the intermediateend wall portion460B, thebarrier426B extends fully across the radial extent of thechannel418B to join the inner and outerside wall portions412B and414B all the way to the bottom of the channel.
• As shown inFIGS. 36 and 37, acollection region458B communicates with twoexit flow paths446B and454B throughcorresponding openings449B and456B to preferably allow removal of plasma and red blood cells, respectively, from thechannel418B. Thecollection region458B further includes an intermediate radially extendingwall portion436B spaced downstream of thebarrier426B and spaced upstream of theexit flow paths446B and454B. As compared to the embodiment ofFIGS. 31-34, the intermediate radially extendingwall portion436B inFIGS. 35-38 does not extend radially inward of the innerside wall portion412B. As best seen inFIG. 36, theintermediate wall portion436B has inner andouter edges438B and439B, respectively, which edges are preferably spaced from the corresponding inner and outerside wall portions412B and414B. InFIGS. 37 and 38 the radially extendingwall portion436B preferably is located closer to the innerside wall portion412B which may allow for priming portions of thechamber410B although other locations of the radially extendingwall portion436B are possible depending on the flow requirements of the procedure.
• InFIG. 37, the interface between the plasma and red blood cells is preferably located approximately between theedges439B and443B during normal conditions—i.e. not under spill or over spill conditions. Plasma radially inward of the interface is preferably allowed to flow from thecollection region458B into theopening449B and theexit flow path446B for removal of plasma from thechannel418B. Red blood cells radially outward of the interface are preferably allowed to flow into the opening456B and through theexit flow path454B for removal of red blood cells from thechannel418B.
J. Tenth Embodiment of the Blood Processing Chamber
• FIGS. 39-42B illustrate another embodiment of a blood separation chamber, generally indicated at500, withFIG. 41 illustrating the path traveled the blood within thechamber500. As with previous embodiments already discussed,chamber500 includes inner and outerside wall portions502 and504 respectively and opposed end wall portions (oneend wall portion506 being shown inFIG. 39) which together define achannel508. The outerside wall portion504 includes a radially outward section505 (FIGS. 39 and 40A) which is positioned radially outward of the outerside wall portion504 of a more upstream location.
• Two radially directed interiorradial walls510 and512 define an inlet, generally at514, which extends outward from ahub501. As best shown inFIG. 42A, theinlet514 includesseveral portion546,548,550 and552 which are generally disposed in different directions. Afirst portion546 extends radially outward of thehub501 between the interiorradial walls510 and512 and is defined in part by the top end wall portion (not shown). Asecond portion548 is axially directed from one end of thefirst portion546 and is defined between the top end wall portion and an intermediate axial location of thechamber500. Athird portion550 is radially directed from one end of thesecond portion548 and is axially offset from thefirst portion546 of theinlet514. Another end of thethird portion550 is defined at a radially outward location which is approximate to the outerside wall portion504. Afourth portion552 is disposed generally orthogonal to thethird portion550 and is directed towards an upstream end of thechannel508 so as to allow fluid to enter thechannel508. InFIG. 41, the fluid path defined by thefourth portion552 is generally parallel to the fluid path defined by thechannel508. As shown inFIG. 41, fluid enters thechannel508 at a location which is axially spaced from the top end wall portion at the top of thechannel508.
• As with previous embodiments, thechannel508 inFIG. 39 includes a barrier, generally indicated at516, having upstream anddownstream sides518 and520. Thebarrier516 extends generally perpendicular to the outerside wall portion504. InFIGS. 40A and 42B, anouter edge522 of thebarrier516 is spaced from the radiallyoutward section505 above an intermediateend wall portion536 and thus defines a first flow path524 (as best seen inFIGS. 40A and 41). Above the intermediateend wall portion536, thefirst flow path524 permits flow around the outerradial edge522 of thebarrier516. Theedge522 has a radial location approximate to that of theouter wall portion504. Thefirst flow path524 is preferably defined axially between the top end wall portion (not shown) of thechannel508 and theintermediate end wall536, which intermediate end wall is spaced from the bottomend wall portion506 of the channel. Below theintermediate end wall536, the outerradial edge522 joins the outerside wall portion504 orsection505 thereof so that flow around thebarrier516 is generally not permitted.
• InFIGS. 40, 40A and42B, thebarrier516 preferably extends radially inward to a radial location which is radially inward of the innerside wall portion502. Thebarrier516 forms a partition between first and secondexit flow paths526 and528. As shown inFIGS. 40 and 40A, the firstexit flow path526 is defined between theupstream side518 of thebarrier516 and an interiorradial wall530. An opening oroutlet532 to such path is disposed at the innerside wall portion502 to allow flow out of the channel upstream of thebarrier516. The secondexit flow path528 is disposed downstream of thebarrier516 and includes anopening534. The secondexit flow path528 is defined between thebarrier516 and the interiorradial wall512. A radiallyoutward edge513 of the interiorradial wall512 is disposed at a radial location which is intermediate the inner and outerside wall portions502 and504.Such edge513 is preferably radially inward of theouter edge522 of thebarrier516.
• As best seen inFIG. 40A, acollection region538 is disposed downstream of the barrier. The collection region preferably is defined in an axial direction between the top end wall portion (not shown) and the intermediate end wall portion536 (see alsoFIG. 42B) which is spaced from the bottomend wall portion506. Thecollection region538 is in fluid communication with thefirst flow path524. InFIG. 40A, thecollection region538 is preferably defined in its radial extent between the innerside wall portion502 and the radiallyoutward section505 of the outerside wall portion504. Theopening534 communicates with thecollection region538 to allow flow of one or more fluid components, preferably red blood cells, to exit through theexit flow path528 and for removal from thechannel508.
• InFIG. 40A, thecollection region538 further includes aradial passageway540 located to the right of the interiorradial wall512. Thepassageway540 is defined between the interiorradial wall512 and anextension portion542 which portion extends radially inward from the outerside wall portion504. Thepassageway540 extends to the innerside wall portion502 where it communicates through anon-radial passageway544 with the portion of thechannel508 located to the right inFIG. 40A. Theextension portion542 terminates at a radial location which is intermediate the inner and outerside wall portions502 and504 and, preferably, terminates at a radial location which is radially inward of theedge513. Theextension portion542 thus locates thenon-radial passageway544 at a location adjacent the innerside wall portion502. Preferably, both radial andnon-radial passageways540 and544 are axially defined between the top end wall portion (not shown) and the intermediateend wall portion536.
• As shown inFIG. 40A, thepassageways540 and544 generally allow communication between the upstream and downstream ends of thechannel508. In this regard, thepassageway544 preferably allows plasma to flow into thecollection region538 from the portion of thechannel508 to the right of thepassageway544. As shown inFIG. 41, plasma flows to the left of theextension portion542, Plasma preferably flows into thecollection region538 when the interface is located at an approximate radial location between theedges513 and522. As previously described,FIG. 42A shows theinlet514 and itsportions546,548,550 and552 which are disposed so as to circumvent a path around thepassageways540 and544 into thechannel508. The positioning of theinlet portion552 at the innerside wall portion502 may help to avoid the flow of whole blood or other fluids into thecollection region538 before the components have the opportunity to undergo sufficient separation.
• InFIG. 40A, plasma preferably exits thechannel508 through theopening532 of the firstexit flow path526 to the left of thebarrier516 inFIG. 40A. Plasma is also allowed to flow through thepassageway544 into thecollection region538 to the right of thebarrier516 inFIG. 40A so as to maintain a volume of plasma above the radial location of the interface. Red blood cells preferably exit through secondexit flow path528. During normal conditions, the interface in thecollection region538 is preferably located between theouter edge522 of thebarrier516 and theedge513 formed on theinterior wall512. Plasma is supplied through thepassageway544 to fill at least a portion of the volume of thecollection region538 radially inward of the interface. The radial location ofsuch edge513 preferably does not allow plasma to flow into the secondexit flow path528.
III. Use of the System to Perform a Concentrated Platelet Collection Procedure
• Any of the above described embodiments may be utilized to perform various biological fluid collection procedures such as a plasma collection procedure, a double-red cell collection procedure, and a platelet collection procedure as well as other collection procedures. Such procedure may be conducted with the blood flow set12 together with thedevice14 andcontroller16 previously described. The blood separation chamber inFIGS. 43-48 will generally be referred to byreference number18 which may include the structure of any of the previously described embodiments.
• Although several platelet collection procedures will be described below, it is understood that the above described embodiments may be used for other collection procedures and may employ more than one collection procedure. By way of example and not limitation, typical plasma and double-red collection procedures have been described in at least one of the above-identified patents or applications which have been incorporated by reference herein. In addition, any of the embodiments described herein may be employed to collect more than one blood component in quantities permitted by the relevant country. Although collection of platelet rich concentrate will be discussed in detail below, it is contemplated that any of these methods in its broadest interpretation may include other biological fluid components as well as other blood components.
• A. Recirculating For Platelet Collection
• FIGS. 43-45 schematically show a method for platelet collection. InFIG. 43, a fluid component, preferably whole blood, is pumped into thechamber18. The blood may flows into thechamber18 either from a blood source, preferably a donor, or may flow from the in-process container158 where the blood from the blood source is temporarily stored for subsequent processing by thechamber18. The whole blood WB is allowed to flow, such as by pumping of an in-process pump IPP, through aninlet flow line102 into thechamber18.
• Within thechamber18, separation of the fluid components occurs based on density as inFIG. 11. As mentioned above, further detail of this separation is set forth in Brown, “The Physics of Continuous Flow Centrifugal Sell Separation,” Artificial Organ, 13(1)4-20 (1989). A higher density component such as red blood cells RBC is forced towards the outer or high-side wall portion and a lower density component such as platelet poor plasma is forced towards an inner or low-g side wall portion. InFIG. 11, the interface between the red blood cells and the plasma contains a buffy coat layer which includes at least a portion of platelets and white blood cells, although the components of the interface will vary based on the particular procedure employed.
• After sufficient time has passed to allow the interface to form, fluid may be collected separately from either side of the interface—or both sides thereof—through therespective outlet tube104 or106 depending on the requirements of the procedure. For example, some platelet poor plasma PPP may be collected radially inward of the interface through theoutlet tube106 and into theplasma collection container160. Some red blood cells RBC may be collected radially outward of the interface through theoutlet tube104 and flow into the red bloodcell collection container162. The afore-described barriers in the above chambers preferably allow accumulation of platelets which are contained in the buffy coat during such plasma or red cell collection, but platelet collection is not yet initiated.
• Prior to collecting the platelets, it is preferred that an under spill condition is imposed upon the fluid components. The under spill condition is shown inFIG. 13. Theoptical sensor148 detects that a portion of the plasma is exiting thetube104 which usually has red blood cells exiting therethrough. The under spill condition is empirically determined based on the optical transmissivity of light through the components in theoutlet tube104. The optical sensor data is converted to a hematocrit. A decrease in hematocrit of theoutlet tube104 detects an under spill condition. Forcing an under spill condition allows the interface to be forced radially outward (FIG. 13) as compared to the radial location of the interface during normal collection operation (FIG. 11). The under spill condition allows removal of red blood cells into the red bloodcell collection container162 until the resulting fluid in the chamber has a hematocrit of approximately in the range of 20 to 40 percent.
• Once a desired hematocrit level is achieved, the fluid in thechamber18 is preferably kept within the desired hematocrit range. For example, the flow of plasma may be stopped to prevent flow toplasma collection container160 and the flow of red blood cells from thechamber18 may also be stopped. Such flow may be stopped by operation of thevalve station30 and/or stopping one or more pumps such as the plasma pump PP. The in-process pump IPP may continue to operate although it is preferably operated at a lower flow rate.
• The method further includes the recombination of the separated fluid components within thechamber18. Recombination is preferably performed by rotation of the chamber in both clockwise and counterclockwise directions. Preferably, thechamber18 is rotated alternately in clockwise and counterclockwise directions one or more times. The step of recombining preferably results in a uniform blood mixture which includes plasma, red blood cells, platelets and white blood cells having an approximate chamber hematocrit as previously described. The step of recombining preferably lasts approximately one to three minutes, although this time period may vary. The rotation of the chamber in either direction is preferably at a rate preferably greatly reduced than the rate of rotation during initial separation of the components and may be, for example, in the range of approximately 300 to 600 RPM, although other rates of rotation are possible. It is noted that the angular velocities used herein conventionally are two omega although one omega may also be used as well as some combination thereof.
• After a sufficient recombination period, the rotor is then restarted to rotate the chamber in a uniform direction so that the flow within the chamber is generally directed from theinlet tube102 to theoutlet tubes104 and106. Although the specific speed of the rotor may vary, such speed may be 2500 RPM. The interface between the plasma and red blood cells is allowed to reform. Preferably, collection of the plasma and red blood cells from thechamber18 is not initiated until the interface is allowed sufficient time to reform.
• After the interface has reformed, the plasma and in-process pumps are operated to draw off plasma from the radially inward side of the interface through theoutlet tube106 and red blood cells are drawn from the radially outward side of the interface throughflow line104. As shown inFIG. 44, both components are diverted back through theinlet tube102 for recirculation through thechamber18. During recirculation, no plasma or red blood cells are collected into theircontainers160 and162. The platelet concentration in the plasma generally increases during recirculation with platelets from the interface becoming suspended in the plasma. Recirculation of both components continues until theoptical sensor146 detects platelet rich plasma which has a desired concentration of platelets and which is visually low in red blood cells. As discussed above, the hematocrit of the recirculated mixture is approximately between 20-40 percent. Recirculation may also be modified so as to recirculate only one of the components, either plasma or red blood cells, as desired.
• During recirculation, the preferred pump flow rate ratio of the in-process pump IPP and plasma pump PP is 60/40, although other pump rates may be used depending on the particular conditions of the system. Recirculation may also allow an increasing concentration of white blood cells to settle to the interface between the platelet rich plasma and the red blood cells. Such pump ratio has also been found to have a direct influence on the number of white blood cells WBC that contaminate the platelet rich plasma PRP and the overall platelet concentration collection efficiency. By way of example and not limitation,FIGS. 45A and 45B show a collected fluid having a higher concentration of platelets (FIG. 45A) and a lower concentration of white blood cells WBC (FIG. 45B). InFIGS. 45A and 45B, such fluid was collected from a chamber having approximately 120 cm²surface area, which was operated at a one omega speed of approximately 1250 RPM with a chamber hematocrit of approximately 25%. Other collection efficiencies may be developed for different chamber surface areas, centrifugal speeds and chamber hematocrits.
• Recirculation of the platelet rich plasma PRP may continue for several minutes, preferably approximately two to four minutes although this range may very depending upon the particular procedure. After a sufficient recirculation period, the platelet rich plasma PRP is collected through theoutlet tube106 into the plateletconcentrate PC container161 as shown inFIG. 45. Also, inFIG. 45, platelet poor plasma PPP replaces the fluid volume lost within thechamber18 due to collection of the platelet rich plasma PRP. Although the collection of platelet rich plasma PRP has been described above, this method may also employ collection of platelet poor plasma and/or red blood cells.
• Various modifications to the above-described method are possible. One modification includes operating the in-process pump IPP between at least two different pumping rates to effect recombination of the blood components. For example, fluid may be pumped into thechamber18 by the in-process pump IPP at a first flow rate while being rotated in a clockwise or counterclockwise direction, and then the rotation in either direction is repeated at a second flow rate. The centrifugal force may be decreased, such as by decreasing the rotor speed, where more than one flow rate is used.
• Another modification to includes operating the plasma pump PP during recombination. Plasma is collected through theoutlet tube106 and flows into the in-process container158. Simultaneously, the flow at theinlet tube102 is reversed using the in-process pump IPP so that fluid from thechamber18 also flows into the in-process container158 through theinlet tube102. The fluid in the in-process container158 is then allowed to flow back into thechamber18 through theinlet tube102. Therefore, the fluid components are mixed together outside of thechamber18 and then re-enter the chamber.
• It is further possible to modify the pump ratio between the in-process IPP and plasma pumps PP during the collection phase to different ratios at different times during the procedure. Another further modification to the method discussed above includes using a platelet additive solution to replace volume within thechamber18 after the platelet rich plasma PRP has been collected.
• In addition, the length of time of recirculation into and out of thechamber18 may be modified. For example, lengthening the recirculation period may allow more white blood cells to be forced radially outward to the interface so that the collected platelet rich plasma PRP has a lower white blood cell count. By way of example and not limitation,FIG. 45C shows platelet and white blood cell counts during recirculation of platelet rich plasma PRP. InFIG. 45C, the first sample occurred 15 seconds after the plasma pump was restarted for recirculation with samples taken approximately every minute thereafter.Sample #5 occurred 15 seconds after beginning collection of platelet rich plasma PRP into theplatelet concentrate container161. The white blood cells concentration drops during recirculation, approximately halving with every sample during the first few minutes. As a result, the lengthening of the recirculation period allows more white blood cells to sediment out of the platelet rich plasma and thus produces a leuko-reduced platelet concentrate which has substantially less white blood cells than at the start of recirculation. Other modifications are also possible.
• B. Decreasing the Centrifugal Force for Platelet Collection
• Another method of platelet collection includes decreasing the centrifugal force in order to separate and collect a desired fluid from the chamber. Such fluid is preferably platelet rich plasma PRP which provides a combination of platelets and plasma having a high platelet concentration.
• Similar to the previously described method ofFIGS. 43-45, this method includes introducing a fluid, preferably whole blood, into any one of the previously described chambers. Centrifugal force is preferably applied by the rotation of the chamber about its axis which causes the separation shown inFIG. 11. Platelets and white blood cells generally settle into the interface or buffy coat layer between the plasma and the red blood cells. Within the interface, at least some separation may occur between the platelets and white blood cells based on density. In this regard, a thin layer of platelets may lie adjacent the plasma. By way of example and not limitation, a rotational speed in the range of approximately 4,500 to 5,000 RPM preferably results a platelet layer within the interface, of approximately 1 to 3 mm thick, although other speeds are also possible.
• After initial separation, the centrifugal force is decreased. Such decrease in force is preferably performed by decreasing the rotational speed of the chamber. The decrease in centrifugal force is preferably sufficient to cause expansion of the platelet layer which resides in the interface, thereby also causing expansion of the interface, as shown inFIG. 46. By way of example and not limitation, a rotation speed of preferably approximately 2,500 RPM provides a platelet layer which is approximately 4 to 6 mm thick.
• Upon thickening of the interface, it is desired to collect as many platelets as possible from the interface or buffy coat, as platelet rich plasma PRP. By way of example and not limitation, collection may be performed by moving the expanded interface radially inward toward the inner side wall portion or low-G wall to create an over spill condition, similar to that shown inFIG. 12. In this respect, theoptical sensor146 optically monitors the presence of platelets in theoutlet tube106. At such point, when a sufficient concentration of platelets are detected within theoutlet tube106, the fluid flow from thechamber18 is allowed to flow into the plateletcollection PC container161. Prior to such point, the fluid flow from thechamber18 may flow into theplasma collection container160.
• Modifications to this method are also possible and such modifications are not limited by the specific structures shown and described herein. In addition, this method may be combined with any of the other methods described herein. Removal of platelets may be performed two or more times during the collection procedure. It is also possible to perform other collection procedures in combination with this method such as separate collection of platelet poor plasma and/or red blood cells.
• C. Repeatedly Forming the Interface for Platelet Collection
• This method provides for collection of a fluid from one side of the interface and then allows the interface to reform preferably to perform another collection of such fluid. Similar to previous methods discussed above, this method preferably introduces whole blood into the chamber and separates the blood into components based on density, as shown inFIG. 11. The interface or buffy coat layer is located at an intermediate radial location between the plasma and red blood cells and contains platelets.
• Collection of the platelets within the interface is performed by forcing an over spill condition whereby the interface is forced radially upward to the inner side wall portion or low-G wall, as shown inFIG. 12. As previously described, platelets are optically monitored in theoutlet tube106 by theoptical sensor146 and platelet rich plasma PRP is diverted to theplatelet collection container161 when theoptical sensor146 detects the presence of a sufficient concentration of platelets within the plasma.
• After a predetermined collection time period, collection is stopped and the interface is allowed to return to its previous intermediate radial location, as shown inFIG. 11. At such location, the interface is allowed time to reform so that platelets which may have moved or diverged from the interface may settle back into the interface. After sufficient time has been allowed for reforming the interface, another over spill over condition is employed so as to allow the interface to move radially inward and to allow more platelet rich plasma PRP to be collected through theoutlet tube106.
• In one modification, the step of removing platelet rich plasma may be repeated at least two times and the interface may be allowed to reform between each successive removal event. In a further modification, this method may be combined with any of the other methods discussed herein. By way of example and not limitation this method may be combined with decreasing the centrifugal force as described above. This method may also be combined with separate platelet poor plasma and/or red blood cell collection.
IV. Use of the System to Perform a Combined RBC/Plasma Collection Procedure
• Any of the previously described chambers may be further utilized to perform a combined red blood cell and plasma collection procedure—which collects red blood cells and plasma separately—instead or in addition to the collection of platelet concentrate collection procedures described above. As such, the system and its components may be modified, as necessary, to perform the steps of this procedure, as described in more detail below.
• A. First Draw Cycle
• As shown inFIG. 47, a blood source BS is fluidly connected so as to allow the blood to be processed by the blood separation device10 (FIG. 1) and its flow set12 (FIGS. 4-6). Fluid entry of the blood into the flow set is schematically shown inFIG. 47. The blood source BS may be a donor or other human subject, as shown, or another blood source connected to the device. Such donor may be connected to the blood separation device, for example by insertion of thephlebotomy needle128 into an arm of the donor. Whole blood may flow into the flow line126 (see alsoFIGS. 5 and 6) where it may be mixed anticoagulant through arespective flow line152 from ananticoagulant reservoir150, as generally shown inFIG. 47.
• After the blood source BS is connected to the device, whole blood WB preferably travels through the appropriate flow tubes as directed by the system to fill thechamber18. Thechamber18 presumably has been prepared for blood processing through one or more pre-collection procedures such as purging the chamber of air and priming the chamber with saline and/or other procedures as appropriate. The whole blood enters thechamber18 throughinlet flow line102 until thechamber18 is full. Whole blood is also drawn from the blood source BS and is temporarily stored in the in-process container158 for subsequent processing by thechamber18. The volume of whole blood which is drawn from the blood source BS is measured such as by the weigh scales62 (FIGS. 3-6) of the system. Collection of whole blood from the blood source BS continues either until a certain predetermined volume of whole blood is reached or to allow a partial or full return cycle, as discussed below. By way of example and not limitation, the procedure may collect approximately 2 units or 800 ml of whole blood during a combined red cell and plasma collection procedure. Other whole blood collection volumes are possible and will depend on the targeted volume and type of components which are being collected.
• Similar to previous methods discussed above, the whole blood within thechamber18 is processed to allow separation into its components based on density, as shown inFIG. 11. After sufficient processing time, a fluid is removed from each side of the interface. Plasma P is removed from one side of the interface. Red blood cells are removed from the other side of the interface. InFIG. 47, plasma P exits thechamber18 through theoutlet tube106 and red blood cell concentrate RBC exits theoutlet tube104.
• The first and second fluid components, preferably plasma and red blood cells, are removed from the chamber into theirrespective collection containers160 and162. The volume of each fluid component collected within thecontainers160 and162 is also measured throughout the collection cycle. Processing and collection of the components from thechamber18 preferably continues until the volume within at least one of thefluid collection containers160 and162 reaches a predetermined minimum threshold, but before a targeted total volume of at least one fluid component is collected. When one of the volumes of thecontainers160 and162 reaches the predetermined minimum threshold, the device is configured to allow a full or partial return of at least one of the blood components.
• B. Return Cycle
• InFIG. 48, a portion of at least one of the fluid components, preferably red blood cells RBC, is returned to the donor. During the return cycle, whole blood from the in-process container158 flows into thechamber18 and also is processed. Separation and collection of the components in thechamber18 preferably continues although at least one of the components may be returned to the blood source, if desired. InFIG. 48, red blood cells RBC exiting thechamber18 are returned to the donor. All or a portion of the red blood cells which are collected up to this point in the procedure may be returned to the donor, and the amount returned may depend on the specific procedure employed.
• FIG. 49 shows a more detailed account of a combined red blood cell and plasma procedure where all the red blood cells are return to the donor at a “Last Return” and all the plasma is stored within the system. While the volume of plasma within theplasma collection container160 may be retained within the system, it is also possible that a portion of the plasma may be returned to the donor, depending on the requirements of the procedure.
• After the desired volume of at least one of the fluid components has been returned to the blood source, the return cycle terminates. Additional return cycles are preferably not commenced, as these would increase the time during which the blood source must be connected to the separation device.
• C. Second Draw Cycle
• After the return cycle, additional whole blood is withdrawn from the blood source and processed, as previously described and shown inFIG. 47. The amount of whole blood which is withdrawn from the blood source BS during the second draw cycle is based on a predicted value. Such value preferably depends on the volumes of plasma and red blood cells which are collected during the first collection cycle and the hematocrit of the red blood cells leaving thechamber18. The volumetric data of plasma in thecontainer160 and the volume of red blood cells in thecontainer162 are preferably monitored throughout the first draw cycle, such as by the weighing sensors, and are also measured at the end of the first draw cycle, prior to any return of such components to the blood source BS. The hematocrit of thechamber18 is determined optically through the sensor148 (FIG. 11) in theoutlet tube104. The system uses the volumetric and hemacrit values to empirically calculate how much whole blood must be withdrawn from the blood source BS to achieve a targeted final volume of at least one of or both fluid components. In its calculation, the system also takes into account whether the volume of plasma or red blood cells which have already been collected will be retained or returned to the blood source BS.
• In the example ofFIG. 49, the volume of plasma retained after the first collection cycle is approximately 160 ml. The volume of red blood cells retained is 0 ml or approximately zero. The targeted volume of plasma and red blood cells are approximately 400 ml and 240 ml, respectively. The additional whole blood to be drawn from the donor to achieve these targeted volumes is determined by the system as approximately 480 ml. Therefore, this is the volume of whole blood which must be drawn during the second collection cycle. Other volumes will be apparent with different volumetric and hemacrit values.
• D. Processing Cycle After Disconnection
• The blood source BS or donor may be disconnected from the device after the predicted volume of whole blood has been withdrawn. Processing of the whole blood is repeated as described above inFIG. 47 for the First Draw Cycle except with the blood source BS being disconnected from the device. Processing of the whole blood continues after disconnection of the donor, thus reducing the actual time that the donor needs to be connected to the device. The total amount of time elapsed during which the blood source BS is connected to the device is thus less than the total amount of time during which the whole blood undergoes collection and processing by the device.
• By way of example and not limitation,FIG. 49 shows collection procedure for approximately 800 ml of whole blood which has a total processing time of approximately 21 minutes. This procedure collects approximately 400 ml of plasma and approximately 240 ml (or 1 unit) of red blood cells—with the remaining red blood cells having been returned to the donor during the return cycle. The total time that the donor is connected to the device is less than the total processing time, —i.e., less than 21 minutes—since the donor may be disconnected after the last return. InFIG. 49, the total time that the donor is connected to the device may be approximately 14 minutes. Other total processing times and donor connection times are possible and may depend on the procedure objectives.
• Preferably, at least two components such as plasma and red blood cells are removed and stored in theirrespective collection containers160 and162, either until the total targeted volume of at least one blood component is reached or until all the blood has been processed. Further processing or separation may be employed in accordance with any of the above described methods or other collection procedures. For example, any one or more of the above methods may be employed to collect platelet concentrate. Platelet poor plasma may be used to resuspend platelets from the interface in accordance with any of the previously described methods. Alternatively, a platelet additive solution or PAS may be used for collecting platelet concentrate methods. Thus, this method may also be combined with any of the above-described to collect at least two blood components, plasma and red blood cells, as well as platelet concentrate. The amount of collection will vary depending on collection limitations set by the particular country.
• As can be seen from the above description, the present invention has several different aspects and features, which are not limited to the specific chamber shown in the attached drawings or to the specific procedures discussed. Variations of these features may be embodied in other structures for carrying out other procedures for blood separation, processing or collection.

Claims (7)

1-100. (canceled)

101. A separation channel for rotation about an axis to separate a biological fluid including:

radially spaced apart inner and outer side wall portions and an end wall portion, the channel having an axial length,

an inlet to convey fluid into the channel;

a barrier located in the channel intermediate the side wall portions and having upstream and downstream sides and an axial end within the channel, the barrier extending to the outer wall portion and joining the outer wall portion along a substantial portion of the axial length of the channel; and

a first flow path communicating between the upstream and downstream sides of the barrier around the axial end of the barrier.

102. The separation channel ofclaim 101 further comprising a second end wall portion being opposed to the first named end wall portion, and at least a portion of the first flow path being located at an intermediate location between the first and second end wall portions.

103. The separation channel ofclaim 101 wherein at least a portion of the first flow path is defined by an axially disposed surface of the barrier, which surface forces at least one blood component in an axial direction of the channel.

104. The separation channel ofclaim 101 further comprising a second end wall portion being opposed to the first named end wall portion, and wherein the first flow path is defined by a surface of the second end wall portion.

105. The separation channel ofclaim 101 wherein the barrier extends to a radial position inward of the inner wall portion.

106. The separation channel ofclaim 101 wherein a surface of the first flow path includes the outer wall portion.

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