Patent Description:
Various blood processing systems now make it possible to collect particular blood constituents, rather than whole blood, from donors or patients or other blood sources. Typically, in such systems, whole blood is drawn from a source, the particular blood component or constituent is removed and collected, and the remaining blood constituents are returned to the source. By thus removing only particular constituents, potentially less time is needed for the source's body to return to normal (in the case of a living source), and donations can be made at more frequent intervals than when whole blood is collected. This increases the overall supply of blood constituents, such as plasma and platelets, made available for health care. <CIT> describes such a processing system, wherein a predetermined volume of whole blood is processed so as to reduce the risk of bacterial contam ination.

Whole blood is typically separated into its constituents through centrifugation. This requires that the whole blood be passed through a centrifuge after it is withdrawn from, and before it is returned to, the source. To avoid contamination and possible infection of the source, the blood is preferably contained within a sealed, sterile fluid flow system during the entire centrifugation process. Typical blood processing systems thus include a permanent, reusable centrifuge assembly containing the hardware (drive system, pumps, valve actuators, programmable controller, and the like) that spins and pumps the blood, and a disposable, sealed and sterile fluid processing assembly that is mounted in cooperation on the hardware. The centrifuge assembly engages and spins a disposable centrifuge chamber of the fluid processing assembly during a collection procedure. The blood, however, makes actual contact only with the fluid processing assembly, which assembly is used only once and then discarded.

As the whole blood is spun by the centrifuge, the heavier (greater specific gravity) components, such as red blood cells, move radially outwardly away from the center of rotation toward the outer or "high-G" wall of the separation chamber. The lighter (lower specific gravity) components, such as plasma, migrate toward the inner or "low-G" wall of the separation chamber. Various ones of these components can be selectively removed from the whole blood by forming appropriately located channeling seals and outlet ports in the separation chamber.

An exemplary method of centrifugally separating and collecting mononuclear cells ("MNCs") is described in <CIT>. In such a procedure, whole blood in a centrifuge is separated into platelet-poor plasma, an interface or MNC-containing layer, and packed red blood cells. The platelet-poor plasma is collected for later use, while the packed red blood cells are returned to the blood source and the MNC-containing layer remains in the centrifuge. When a target amount of platelet-poor plasma has been collected, an MNC accumulation phase begins. During this phase, the position of the interface within the centrifuge is moved closer to the low-G wall, such that platelet-rich plasma and packed red blood cells are removed from the centrifuge while the MNC-containing layer continues to build up in the centrifuge. Portions of the platelet-rich plasma and the packed red blood cells are returned to the blood source, with the remainder of the platelet-rich plasma and packed red blood cells being recirculated through the centrifuge to maintain a proper hematocrit.

When a certain amount of blood has been processed, the return and recirculation of the packed red cells is ended and a red blood cell collection phase begins. During this phase, recirculation and return of the platelet-rich plasma continues, while the packed red blood cells are conveyed from the centrifuge to a red blood cell collection container for later use.

When a target amount of packed red blood cells has been collected, an MNC harvest phase begins. To harvest the MNCs in the MNC-containing layer, the packed red blood cells are temporarily prevented from exiting the centrifuge. At least a portion of the collected red blood cells is conveyed into the centrifuge, which forces the MNC-containing layer to exit the centrifuge via the same outlet as the platelet-rich plasma. The platelet-rich plasma exiting the centrifuge ahead of the MNC-containing layer is directed into the platelet-poor plasma container, with the MNC-containing layer subsequently being directed into an MNC collection container.

Following the MNC harvest phase, a plasma flush phase begins. During this phase, plasma from the platelet-poor plasma container is used to flush any MNC-containing layer positioned between the separation chamber and the MNC collection container back into the separation chamber. The MNC-containing layer flushed back into the separation chamber may be subsequently collected by repeating the various phases, until a target amount of MNC product has been collected. Following collection, the MNC product may be treated to further processing, such as extracorporeal photopheresis.

For any of a number of reasons, the MNC-collection procedure may be terminated mid-process. If a sufficient amount of packed red blood cells has not been collected at the time of termination, the MNC-containing layer cannot be fully harvested using conventional techniques. Accordingly, it would be advantageous to provide alternative approaches to MNC collection to allow for more complete collection of the MNC-containing layer in the event of mid-process termination.

There are several aspects of the present subject matter which may be embodied separately or together in the devices and systems described and claimed below. These aspects may be employed alone or in combination with other aspects of the subject matter described herein, and the description of these aspects together is not intended to preclude the use of these aspects separately or the claiming of such aspects separately or in different combinations as set forth in the claims appended hereto.

In one aspect, a method is provided for collecting mononuclear cells. The method includes, separating red blood cells from blood in a separation chamber and conveying at least a portion of the separated red blood cells from the separation chamber to a red blood cell collection container. A mononuclear cell-containing layer is separated from blood in the separation chamber while red blood cells are removed from the separation chamber. At least a portion of the removed red blood cells is recirculated through the separation chamber, while allowing a volume of the mononuclear cell-containing layer to increase in the separation chamber. At least a portion of the contents of the red blood cell collection container is conveyed to the separation chamber to convey at least a portion of the mononuclear cell-containing layer out of the separation chamber for collection, with the separated red blood cells being conveyed to the red blood cell collection container prior to recirculating the removed red blood cells through the separation chamber.

In another aspect, a fluid processing system includes a centrifuge configured to receive a separation chamber of a fluid processing assembly. The fluid processing system also includes a plurality of pumps configured to convey fluids through the fluid processing assembly. A controller of the fluid processing system is programmed to actuate the centrifuge to separate red blood cells from blood in the separation chamber and actuate at least one of the plurality of pumps to convey at least a portion of the separated red blood cells from the separation chamber to a red blood cell collection container of the fluid processing assembly. The controller is further programmed to actuate the centrifuge to separate a mononuclear cell-containing layer from blood in the separation chamber while actuating at least one of the plurality of pumps to remove red blood cells from the separation chamber, actuating at least one of the plurality of pumps to recirculate at least a portion of the removed red blood cells through the separation chamber, and allowing a volume of the mononuclear cell-containing layer to increase in the separation chamber. The controller is also programmed to actuate at least one of the plurality of pumps to convey at least a portion of the contents of the red blood cell collection container to the separation chamber to convey at least a portion of the mononuclear cell-containing layer out of the separation chamber for collection, with the controller being programmed such that the separated red blood cells are conveyed to the red blood cell collection container prior to recirculating the removed red blood cells through the separation chamber.

In yet another aspect, a method is provided for collecting mononuclear cells. The method includes conveying blood to a red blood cell collection container; separating a mononuclear cell-containing layer from blood in a separation chamber while removing red blood cells from the separation chamber. At least a portion of the removed red blood cells is recirculated through the separation chamber, while allowing a volume of the mononuclear cell-containing layer to increase in the separation chamber. At least a portion of the contents of the red blood cell collection container is conveyed to the separation chamber to convey at least a portion of the mononuclear cell-containing layer out of the separation chamber for collection, with blood being conveyed to the red blood cell collection container prior to recirculating the removed red blood cells through the separation chamber.

In another aspect, a fluid processing system includes a centrifuge configured to receive a separation chamber of a fluid processing assembly, along with a plurality of pumps configured to convey fluids through the fluid processing assembly. A controller of the fluid processing system is programmed to actuate at least one of the plurality of pumps to convey blood to a red blood cell collection container of the fluid processing assembly. The controller is further programmed to actuate the centrifuge to separate a mononuclear cell-containing layer from blood in the separation chamber while actuating at least one of the plurality of pumps to remove red blood cells from the separation chamber, actuating at least one of the plurality of pumps to recirculate at least a portion of the removed red blood cells through the separation chamber, and allowing a volume of the mononuclear cell-containing layer to increase in the separation chamber. The controller is also programmed to actuate at least one of the plurality of pumps to convey at least a portion of the contents of the red blood cell collection container to the separation chamber to convey at least a portion of the mononuclear cell-containing layer out of the separation chamber for collection, with the controller being programmed such that blood is conveyed to the red blood cell collection container prior to recirculating the removed red blood cells through the separation chamber.

In yet another aspect, a method is provided for collecting mononuclear cells. The method includes conveying blood through a cassette and a drip chamber of a fluid processing assembly to a separation chamber of the fluid processing assembly. A mononuclear cell-containing layer is separated from the blood in the separation chamber, with other blood components being removed from the separation chamber while a volume of the mononuclear cell-containing layer increases in the separation chamber. Blood from the cassette and/or the drip chamber is conveyed to a red blood cell collection container of the fluid processing assembly, with at least a portion of the contents of the red blood cell collection container being conveyed to the separation chamber to convey at least a portion of the mononuclear cell-containing layer out of the separation chamber for collection.

In another aspect, a fluid processing system includes a centrifuge configured to receive a separation chamber of a fluid processing assembly, along with a plurality of pumps configured to convey fluids through the fluid processing assembly. A controller of the fluid processing assembly is programmed to actuate at least one of the plurality of pumps to convey blood through a cassette and a drip chamber of the fluid processing assembly to the separation chamber. The controller is further programmed to actuate the centrifuge to separate a mononuclear cell-containing layer from blood in the separation chamber, while actuating at least one of the plurality of pumps to remove other blood components from the separation chamber and allowing a volume of the mononuclear cell-containing layer to increase in the separation chamber. The controller is also programmed to actuate at least one of the plurality of pumps to convey blood from the cassette and/or the drip chamber to a red blood cell collection container of the fluid processing assembly, and actuate at least one of the plurality of pumps to convey at least a portion of the contents of the red blood cell collection container to the separation chamber to convey at least a portion of the mononuclear cell-containing layer out of the separation chamber for collection.

In yet another aspect, a method is provided for collecting mononuclear cells. The method includes conveying blood through a first cassette of a fluid processing assembly to a separation chamber of the fluid processing assembly. A mononuclear cell-containing layer and red blood cells are separated from the blood in the separation chamber, with at least a portion of the red blood cells being conveyed out of the separation chamber and through a second cassette of the fluid processing assembly while a volume of the mononuclear cell-containing layer increases in the separation chamber. Saline is conveyed through the first cassette and/or the second cassette to convey blood and/or red blood cells from the first cassette and/or the second cassette to a red blood cell collection container of the fluid processing assembly, with at least a portion of the contents of the red blood cell collection container being conveyed to the separation chamber to convey at least a portion of the mononuclear cell-containing layer out of the separation chamber for collection.

In another aspect, a fluid processing system includes a centrifuge configured to receive a separation chamber of a fluid processing assembly, along with a plurality of pumps configured to convey fluids through the fluid processing assembly. A controller of the fluid processing system is programmed to actuate at least one of the plurality of pumps to convey blood through a first cassette of a fluid processing assembly to the separation chamber. The controller is further programmed to actuate the centrifuge to separate a mononuclear cell-containing layer and red blood cells from blood in the separation chamber while actuating at least one of the plurality of pumps to convey at least a portion of the red blood cells out of the separation chamber and through a second cassette of the fluid processing assembly, allowing a volume of the mononuclear cell-containing layer to increase in the separation chamber. The controller is also programmed to actuate at least one of the plurality of pumps to convey saline through the first cassette and/or the second cassette to convey blood and/or red blood cells from the first cassette and/or the second cassette to a red blood cell collection container of the fluid processing assembly, with at least one of the plurality of pumps being actuated to convey at least a portion of the contents of the red blood cell collection container to the separation chamber, which conveys at least a portion of the mononuclear cell-containing layer out of the separation chamber for collection.

In yet another aspect, a fluid processing assembly is provided, with the fluid processing assembly being configured for use in combination with a fluid processing system. The fluid processing assembly includes a separation chamber configured to separate a fluid into two or more fluid components, with the separation chamber having an inlet flow path and an outlet flow path. A draw line is provided in fluid communication with the inlet flow path and configured for direct connection to a source to draw a fluid from the source into the fluid processing assembly, while a return line is provided in fluid communication with the outlet flow path and configured for direct connection to the source to convey a replacement fluid and/or at least a portion of a separated fluid component to the source. The draw line includes a first connector, while the return line includes a second connector configured to be connected to the first connector, with connection of the first and second connectors removing one of the draw and return lines from direct connection to the source while placing the other one of the draw and return lines into condition for drawing fluid from the source into the fluid processing assembly and conveying a replacement fluid and/or at least a portion of a separated fluid component to the source.

In another aspect, a method is provided for processing a fluid. The method includes directly connecting a draw line and a return line of a fluid processing assembly to a source, drawing fluid from the source into the fluid processing assembly via the draw line, and processing at least a portion of the fluid within the fluid processing assembly. The processing of the fluid is paused, followed by the draw line and the return line being directly connected so as to remove one of the draw and return lines from direct connection to the source. Thereafter, processing of the fluid is unpaused.

In yet another aspect, a method is provided for processing a fluid. The method includes providing a fluid processing assembly having a draw line and a return line each configured to be directly connected to a source. The draw line and the return line are directly connected so as to prevent one of the draw and return lines from being directly connected to the source. The other one of the draw and return lines is directly connected to the source, followed by fluid being drawn from the source, with at least a portion of the fluid being processed within the fluid processing assembly.

Therefore, specific designs and features disclosed herein are not to be interpreted as limiting the subject matter as defined in the accompanying claims.

<FIG> and <FIG> show a centrifugal fluid processing system <NUM> with a system controller including an interface controller <NUM> (<FIG>) that may be used in practicing the MNC collection principles of the present disclosure. The system is currently marketed as the AMICUS® separator by Fenwal, Inc. of Lake Zurich, Illinois, which is an affiliate of Fresenius Kabi AG of Bad Homburg, Germany, as described in greater detail in <CIT>. The system <NUM> can be used for processing various fluids, but is particularly well suited for processing whole blood, blood components, or other suspensions of biological cellular materials. While MNC collection principles will be described herein with reference to one particular system <NUM>, it should be understood that these principles may be employed with other fluid processing systems without departing from the scope of the present disclosure.

The fluid processing system <NUM> includes a centrifuge <NUM> used to centrifugally separate fluid components. The system <NUM> may be programmed to separate blood into a variety of components (e.g., platelet-rich plasma and red cells), with various MNC collection procedures, in which the system <NUM> separates and collects MNCs (e.g., lymphocytes and monocytes) from whole blood, being described herein.

The illustrated centrifuge <NUM> is of the type shown in <CIT>. The centrifuge comprises a bowl <NUM> and a spool <NUM>. The bowl <NUM> and spool <NUM> are pivoted on a yoke <NUM> between an operating position (<FIG>) and a loading/unloading position (<FIG>).

When in the loading/unloading position, the spool <NUM> can be opened by movement at least partially out of the bowl <NUM>, as <FIG> shows. In this position, the operator wraps a flexible separation chamber <NUM> (see <FIG>) about the spool <NUM>. Closure of the spool <NUM> and bowl <NUM> encloses the chamber <NUM> for processing. When closed, the spool <NUM> and bowl <NUM> are pivoted into the operating position of <FIG> for rotation about an axis.

The separation chamber <NUM> can be variously constructed. <FIG> shows a representative embodiment, while <FIG> shows the separation chamber <NUM> in the context of a disposable fluid processing assembly that is used in combination with the system <NUM> to define a fluid flow path for blood, separated blood components, and other fluids (e.g., anticoagulant). <FIG> illustrates a fluid processing assembly having a "double-needle" configuration in which separate draw and return lines are provided for direct connection to a source for drawing blood into the fluid processing assembly (via the draw line) and returning a separated blood component or some other fluid (e.g., a replacement fluid) to the source (via the return line). The MNC collection techniques described herein may also be practiced using a fluid processing assembly having a "single needle" configuration (as in <FIG> and <FIG>) in which a single access line is directly connected to a source for alternately drawing blood into the fluid processing assembly and returning a separated blood component or some other fluid to the source.

The chamber <NUM> shown in <FIG> allows for either single- or multi-stage processing. When used for multi-stage processing, a first stage <NUM> separates whole blood into first and second components. Depending on the nature of the separation procedure, one of the components may be transferred into a second stage <NUM> for further separation. When used for single-stage processing, only the first stage <NUM> is used for separating blood into its constituents, while the second stage <NUM> may be filled with saline or the like to balance the chamber <NUM>.

As <FIG> best show, there are three ports <NUM>, <NUM>, and <NUM> associated with the first stage <NUM>. Depending on the particular blood processing procedure, the ports may have different functionality but, in an MNC collection procedure, the port identified at <NUM> is used for conveying fluids into the first stage <NUM>. During such an MNC collection procedure, the other two ports <NUM> and <NUM> serve as outlet ports for separated blood components exiting the first stage <NUM>. More particularly, the first outlet port <NUM> conveys a low density blood component from the first stage <NUM>, while the second outlet port <NUM> conveys a high density blood component from the first stage <NUM>.

In a method of carrying out single-stage processing, at least a portion of one or more of the separated components is returned to the fluid source (which may be a living patient or donor or a non-living source, such as a fluid container), while at least a portion of at least one of the other separated components is removed from the first stage <NUM> and stored. For example, a conventional MNC collection procedure (as described in greater detail in <CIT>) begins with a plasma collection phase. During this initial phase, whole blood in the first stage <NUM> is separated into a plasma constituent (i.e., a low density component, which may include platelets), an interface or buffy coat or MNC-containing layer (i.e., an intermediate density component, which includes MNCs and may also include smaller red blood cells), and packed red blood cells (i.e., a high density component). The plasma constituent and packed red blood cells are removed from the first stage <NUM> (via the first and second outlet ports <NUM> and <NUM>, respectively), while the MNC-containing layer builds up in the first stage <NUM>. The plasma constituent is collected, while the packed red blood cells are returned to the blood source.

When a target amount of plasma has been collected, an MNC accumulation phase begins. During this phase, the position of the interface within the first stage <NUM> is moved closer to the spool <NUM>, such that platelet-rich plasma and packed red blood cells are removed from the first stage <NUM> (via the first and second outlet ports <NUM> and <NUM>) while the MNC-containing layer continues to build up in the first stage <NUM>. Portions of the platelet-rich plasma and the packed red blood cells are returned to the blood source, with the remainder of the platelet-rich plasma and packed red blood cells being recirculated through the first stage <NUM> to maintain a proper hematocrit.

When a target or preselected amount of blood has been processed, the system <NUM> transitions to a red blood cell collection phase. During this phase, blood separation continues as in the MNC accumulation phase, with recirculation and return of the platelet-rich plasma continuing, while the separated red blood cells are conveyed from the first stage <NUM> and collected for later use rather than being recirculated or returned to the source.

When a target amount of red blood cells have been collected, the system <NUM> transitions to an MNC harvest phase. To harvest the MNCs in the MNC-containing layer, the second outlet port <NUM> is closed to temporarily prevent packed red blood cells from exiting the first stage <NUM>. At least a portion of the collected red blood cells is conveyed into the first stage <NUM> via the inlet port <NUM>, which forces the MNC-containing layer to exit the first stage <NUM> via the first outlet port <NUM> for collection in an MNC collection container as an MNC product.

Following the MNC harvest phase, a plasma flush phase begins. During this phase, collected plasma is used to flush any MNC-containing layer positioned between the separation chamber <NUM> and the MNC collection container back into the first stage <NUM>. A portion of the collected plasma may be conveyed into the MNC collection container as a storage or suspension medium for the MNC product.

If additional MNC product is to be collected, the various phases may be repeated. Following collection, the MNC product may be treated to further processing, such as extracorporeal photopheresis.

In a different separation procedure, in which multi-stage processing is required, one of the separated blood components will be transferred from the first stage <NUM> to the second stage <NUM> via a port <NUM> associated with the second stage <NUM>. The component transferred to the second stage <NUM> is further fractionated into sub-components, with one of the sub-components being removed from the second stage <NUM> via an outlet port <NUM> and the other sub-component remaining in the second stage <NUM>.

As best shown in <FIG>, a tubing umbilicus <NUM> is attached to the ports <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>. The umbilicus <NUM> interconnects the first and second stages <NUM> and <NUM> with each other and with pumps and other stationary components located outside the rotating components of the centrifuge <NUM> (not shown). As <FIG> shows, a non-rotating (zero omega) holder <NUM> holds the upper portion of the umbilicus <NUM> in a non-rotating position above the spool <NUM> and bowl <NUM>. A holder <NUM> on the yoke <NUM> rotates the mid-portion of the umbilicus <NUM> at a first (one omega) speed about the suspended spool <NUM> and bowl <NUM>. Another holder <NUM> (<FIG> and <FIG>) rotates the lower end of the umbilicus <NUM> at a second speed twice the one omega speed (the two omega speed), at which speed the spool <NUM> and bowl <NUM> also rotate. This known relative rotation of the umbilicus <NUM> keeps it untwisted, in this way avoiding the need for rotating seals.

As <FIG> shows, a first interior seal <NUM> is located between the low density outlet port <NUM> and the inlet port <NUM>. A second interior seal <NUM> is located between the inlet port <NUM> and the high density outlet port <NUM>. The interior seals <NUM> and <NUM> form a fluid passage <NUM> (an inlet for whole blood or the like) and a low density collection region <NUM> in the first stage <NUM>. The second seal <NUM> also forms a fluid passage <NUM> (a high density blood component outlet in an MNC collection procedure) in the first stage <NUM>.

In an MNC collection procedure, the fluid passage <NUM> channels blood directly into the circumferential flow path immediately next to the low density collection region <NUM>. As shown in <FIG>, the blood separates into an optically dense layer <NUM> containing cellular components, which forms as cellular components move under the influence of centrifugal force toward the high-G (outer) wall <NUM>. The optically dense layer <NUM> will include red blood cells (and, hence, will be referred to herein as the "RBC layer") but, depending on the speed at which the centrifuge <NUM> is spun, other cellular components (e.g., larger white blood cells and platelets) may also be present in the RBC layer <NUM>.

The movement of the component(s) of the RBC layer <NUM> displaces less dense blood components radially toward the low-G (inner) wall <NUM>, forming a second, less optically dense layer <NUM>. The less optically dense layer <NUM> includes plasma (and, hence, will be referred to herein as the "plasma layer or plasma constituent") but, depending on the speed at which the centrifuge <NUM> is rotated and the length of time that the blood is resident in the centrifuge, other components (e.g., smaller platelets) may also be present in the plasma layer <NUM>.

The transition between the RBC layer <NUM> and the plasma layer <NUM> is generally referred to as the interface or buffy coat or MNC-containing layer <NUM>, as described above and shown in <FIG>. Platelets and white blood cells (including MNCs) typically occupy this transition region.

The location of the interface <NUM> within the chamber <NUM> can dynamically shift during blood processing, as <FIG> show. If the location of the interface <NUM> is too high (that is, if it is too close to the low-G wall <NUM> and the removal port <NUM>, as <FIG> shows), red blood cells can spill over and into the low density collection region <NUM>, adversely affecting the quality of the plasma constituent <NUM>. On the other hand, if the location of the interface <NUM> is too low (that is, if it resides too far away from the low-G wall <NUM>, as <FIG> shows), the collection efficiency of the system <NUM> may be impaired.

As <FIG> shows, a ramp <NUM> extends from the high-G wall <NUM> of the bowl <NUM> at an angle across the low density collection region <NUM>. The angle, measured with respect to the axis of the first outlet port <NUM> is about <NUM>° in one embodiment. <FIG> shows the orientation of the ramp <NUM> when viewed from the low-G wall <NUM> of the spool <NUM>. <FIG> shows, in phantom lines, the orientation of the ramp <NUM> when viewed from the high-G wall <NUM> of the bowl <NUM>.

Further details of the angled relationship of the ramp <NUM> and the first outlet port <NUM> can be found in <CIT>.

The ramp <NUM> forms a tapered wedge that restricts the flow of fluid toward the first outlet port <NUM>. The top edge of the ramp <NUM> extends to form a constricted passage <NUM> along the low-G wall <NUM>. The plasma layer <NUM> must flow through the constricted passage <NUM> to reach the first outlet port <NUM>.

As <FIG> shows, the ramp <NUM> makes the interface <NUM> between the RBC layer <NUM> and the plasma layer <NUM> more discernible for detection, displaying the RBC layer <NUM>, plasma layer <NUM>, and interface <NUM> for viewing through the high-G wall <NUM> of the chamber <NUM>.

Further details of the separation chamber <NUM> and its operation may be found in <CIT>.

The interface controller <NUM> (<FIG>) includes a viewing head or interface optical sensor assembly <NUM> carried on the yoke <NUM> (see <FIG> and <FIG>) and an outlet optical sensor assembly <NUM> which is associated with tubing connected to the first outlet port <NUM>. Alternatively, rather than being carried on the yoke <NUM>, the interface optical sensor assembly <NUM> may be mounted to a radial location of the centrifuge bucket or enclosure, as described in <CIT> and <CIT>. The interface optical sensor assembly <NUM> is oriented to optically view the transition in optical density between the RBC layer <NUM> and the plasma layer <NUM> on the ramp <NUM>. The outlet optical sensor assembly <NUM> monitors the optical density of fluid exiting the first stage <NUM> via the first outlet port <NUM>.

The interface controller <NUM> is functional to determine the location of the interface <NUM> on the ramp <NUM> and, if the interface <NUM> is located at an improper location (e.g., in the locations of <FIG>), to correct the location of the interface <NUM>.

Referring to <FIG>, the interface optical sensor assembly <NUM>, carried by the yoke <NUM> or mounted to a stationary radial location of the centrifuge bucket or enclosure, includes a light source <NUM>, which emits light that is absorbed by red blood cells. In the illustrated embodiment, the light source <NUM> includes a circular array of red light emitting diodes <NUM>, but other wavelengths absorbed by red blood cells, like green or infrared, could also be used.

In the illustrated embodiment, seven light emitting diodes <NUM> comprise the light source <NUM>. More diodes <NUM> may be used, or fewer diodes <NUM> can be used, depending upon the optical characteristics desired. Further, non-LED lights may also be employed without departing from the scope of the present disclosure.

The interface optical sensor assembly <NUM> also includes a light detector <NUM> (<FIG>), which is mounted adjacent to the light source <NUM>. In one embodiment, the light detector <NUM> comprises a PIN diode detector, which is located generally in the geometric center of the circular array of light emitting diodes <NUM>. Other types of light detectors may also be employed.

If mounted to the yoke <NUM>, the yoke <NUM> and the interface optical sensor assembly <NUM> rotate at a one omega speed, as the spool <NUM> and bowl <NUM> rotate at an average speed of two omega. If mounted to a stationary portion of the centrifuge bucket or enclosure, the interface optical sensor assembly <NUM> remains stationary while the yoke <NUM> rotates at a one omega speed and the spool <NUM> and bowl <NUM> rotate at an average speed of two omega. The light source <NUM> directs light onto the rotating bowl <NUM>. In the illustrated embodiment, the bowl <NUM> is transparent to the light emitted by the source <NUM> only in the region <NUM> where the bowl <NUM> overlies the interface ramp <NUM> (<FIG>). In the illustrated embodiment, the region <NUM> comprises a window cut out in the bowl <NUM>. The remainder of the bowl <NUM> that lies in the path of the interface optical sensor assembly <NUM> comprises an opaque or light absorbing material.

The interface ramp <NUM> is made of a light transmissive material. The light from the source <NUM> will thereby pass through the transparent region <NUM> of the bowl <NUM> and the ramp <NUM> every time the rotating bowl <NUM> and interface optical sensor assembly <NUM> align. The spool <NUM> may also carry a light reflective material <NUM> (<FIG>) behind the interface ramp <NUM> to enhance its reflective properties. The spool <NUM> reflects incoming light received from the source <NUM> out through the transparent region <NUM> of the bowl <NUM>, where it is sensed by the detector <NUM>. In the illustrated embodiment, light passing outward from the source <NUM> and inward toward the detector <NUM> passes through a focusing lens <NUM> (shown in <FIG>), which forms a part of the viewing head <NUM>.

Such an arrangement optically differentiates the reflective properties of the interface ramp <NUM> from the remainder of the bowl <NUM>. This objective can be achieved in other ways. For example, the light source <NUM> could be gated on and off with the arrival and passage of the ramp <NUM> relative to its line of sight. As another example, the bowl <NUM> outside the transparent region <NUM> could carry a material that reflects light, but at a different intensity than the reflective material <NUM> behind the interface ramp <NUM>.

As the transparent interface region <NUM> of the bowl <NUM> comes into alignment with the interface optical sensor assembly <NUM>, the detector <NUM> will first sense light reflected through the plasma layer <NUM> on the ramp <NUM>. Eventually, the RBC layer <NUM> adjacent the interface <NUM> on the ramp <NUM> will enter the optical path of the interface optical sensor assembly <NUM>. The RBC layer <NUM> absorbs light from the source <NUM> and thereby reduces the previously sensed intensity of the reflected light. The length of time that the higher intensity of reflected light is sensed by the detector <NUM> represents the amount of light from the source <NUM> that is not absorbed by the RBC layer <NUM> adjacent to the interface <NUM>. With this information, a processing element or module <NUM> (<FIG>) can determine the location of the interface <NUM> on the ramp <NUM> relative to the constricted passage <NUM>. A more detailed discussion of the algorithms by which the interface controller <NUM> receives and processes signals to determine the location of the interface <NUM> on the ramp <NUM> may be found in <CIT>.

When the location of the interface <NUM> on the ramp <NUM> has been determined, the processing element <NUM> outputs that information to an interface command element or module <NUM> (<FIG>). The command element <NUM> includes a comparator, which compares the interface location output with a desired interface location to generate an error signal. The error signal may take a number of forms but, in one embodiment, is expressed in terms of a targeted red blood cell percentage value (i.e., the percentage of the ramp <NUM> which should be occupied by the RBC layer <NUM>).

When the control value is expressed in terms of a targeted red blood cell percentage value, a positive error signal indicates that the RBC layer <NUM> on the ramp <NUM> is too small (as <FIG> shows). The interface command element <NUM> generates a signal to adjust an operational parameter accordingly, such as by increasing the rate at which plasma is removed through the first outlet port <NUM> under action of a pump <NUM> (<FIG>). The interface <NUM> moves toward the constricted passage <NUM> to the desired control position (as <FIG> shows), where the error signal is zero.

A negative error signal indicates that the RBC layer <NUM> on the ramp <NUM> is too large (as <FIG> shows). The interface command element <NUM> generates a signal to adjust an operational parameter accordingly, such as by decreasing the rate at which plasma is removed through the first outlet port <NUM>. The interface <NUM> moves away from the constricted passage <NUM> to the desired control position (<FIG>), where the error signal is again zero.

The interface controller <NUM> further includes an outlet optical sensor assembly <NUM> (<FIG>), which is configured to monitor the optical density of plasma outside of the separation chamber <NUM>. The outlet optical sensor assembly <NUM> may be positioned anywhere in the fluid circuit outside of the blood separation chamber <NUM> where separated plasma is present but, in the illustrated embodiment is associated with tubing <NUM> connected to the first outlet port <NUM> so as to monitor plasma exiting the first stage <NUM> (or any other fluid exiting the first stage <NUM> via the first outlet port <NUM>). The outlet optical sensor assembly <NUM> compares the optical density of separated plasma to a baseline fluid (e.g., saline) exiting the first outlet port <NUM>. If the optical density of the plasma is significantly different from saline (i.e., if the plasma has a reduced clarity), then it may be indicative of conditions of lipemia, hemolysis, or hyperbilirubinemia. The outlet optical sensor assembly <NUM> may also detect a change in the nature of the fluid exiting the first outlet port <NUM>, such as when the fluid transitions from plasma to the MNC-containing layer during the MNC harvest phase of an MNC collection procedure.

The outlet optical sensor assembly <NUM> includes an optical monitor <NUM> (see <FIG>), which senses the optical density of fluid exiting the first outlet port <NUM> or (in the case of a multi-stage separation procedure) entering the second stage inlet port <NUM>. In one embodiment, the optical monitor <NUM> is a conventional hemoglobin detector of the type used on the Autopheresis-C® blood processing device sold by Fenwal, Inc. The optical monitor <NUM> comprises a red light-emitting diode <NUM>, which emits light into the outlet tubing <NUM> connected to the first outlet port <NUM> on the outside of the blood separation chamber <NUM>. The optical monitor <NUM> further includes a PIN diode detector <NUM> on the opposite side of the tubing <NUM>.

Different or additional light sources could also be used without departing from the scope of the present disclosure. For example, it may be advantageous to include separate red and green light-emitting diodes to distinguish between lipemic and hemolytic conditions in the whole blood and/or plasma layer <NUM>. If, when considering plasma in the tubing <NUM>, the overall transmissivity of the plasma is below a certain level (indicating that the plasma is relatively turbid and may be either lipemic or hemolytic), the red and green transmissions are separately considered. If the red and green transmissions decrease by a similar percentage (from the level of transmission through saline), then it is indicative of lipemia (because green and red light are absorbed to a similar extent by lipids). However, if the green transmission decreases to a much greater degree than the red transmission, it is indicative of hemolytic plasma (because green light is more readily absorbed by hemoglobin than red light).

The outlet optical sensor assembly <NUM> also includes a processing element <NUM>, which receives signals from the monitor <NUM> to compute the optical transmission of the liquid conveyed through the tubing <NUM> by operation of a pump <NUM> of the fluid processing system <NUM>. A more detailed discussion of a set of exemplary algorithms by which the optical densities of the tubing <NUM> itself, saline present in the tubing <NUM>, and other fluid in the outlet tubing <NUM> may be determined can be found in <CIT>.

According to one approach, the conventional MNC collection procedure is replaced with a modified procedure. In general, such modified procedures increase the volume of red blood cells in the fluid processing assembly earlier in the procedure than in the conventional approach, which is advantageous if the procedure is terminated early because it ensures that a sufficient volume of red blood cells will be available for MNC collection.

Such modified procedures may require a greater volume of extracorporeal blood and/or a higher hematocrit than is required in a conventional procedure. Therefore, prior to beginning an MNC collection procedure, the system controller may ascertain whether the blood source can tolerate an alternative MNC collection procedure of the type described herein. If it is determined that an alternative MNC collection procedure is practicable (i.e., if the blood source has at least a minimum total blood volume and/or a minimum hematocrit), then the conventional MNC collection procedure may be replaced by one of the alternative MNC collection procedures described herein. Notably, the alternative MNC collection procedures described herein may be practiced using the same fluid processing system <NUM> and fluid processing assembly that are used for the conventional MNC collection procedure. Accordingly, an operator or technician does not need to know which MNC collection procedure will be executed when mounting a fluid processing assembly to the fluid processing system <NUM>.

According to one alternative MNC collection procedure, the conventional MNC collection procedure is modified by executing the red blood cell collection phase before the MNC accumulation phase. Thus, the modified MNC collection procedure begins with a plasma collection phase, as in the conventional MNC collection procedure. During this initial phase, whole blood in the first stage <NUM> of the separation chamber <NUM> is separated into platelet-poor plasma, the MNC-containing layer, and red blood cells. The platelet-poor plasma and red blood cells are removed from the first stage <NUM> (via the first and second outlet ports <NUM> and <NUM>, respectively), while the MNC-containing layer builds up in the first stage <NUM>. The platelet-poor plasma is collected, while the red blood cells are returned to the blood source.

When a target amount of plasma has been collected, the system <NUM> transitions to a red blood cell collection phase, rather than an MNC accumulation phase (which is the second phase in a conventional MNC collection procedure). During this phase, the position of the interface within the first stage <NUM> is moved closer to the low-G wall <NUM>, such that platelet-rich plasma and packed red blood cells are removed from the first stage <NUM> (via the first and second outlet ports <NUM> and <NUM>, respectively) while the MNC-containing layer continues to build up in the first stage <NUM>. At least a portion of the platelet-rich plasma is recirculated through the separation chamber <NUM>, while another portion of the platelet-rich plasma may be returned to the blood source. The separated red blood cells are conveyed from the first stage <NUM> and collected for later use.

When a target amount of red blood cells has been collected, the system <NUM> transitions to an MNC accumulation phase. During this phase, blood separation continues as in the red blood cell collection phase, with blood in the separation chamber <NUM> being separated into a plasma constituent, MNC-containing layer, and packed red blood cells. Portions of the plasma constituent and the packed red blood cells are returned to the blood source, with the remainder of the platelet-rich plasma and packed red blood cells being recirculated through the first stage <NUM> to maintain a proper hematocrit.

When a target or preselected amount of blood has been processed, the system <NUM> transitions to an MNC harvest phase. To harvest the MNCs in the MNC-containing layer, the second outlet port <NUM> is closed to temporarily prevent packed red blood cells from exiting the first stage <NUM>. At least a portion of the collected red blood cells is conveyed into the first stage <NUM> via the inlet port <NUM>, which forces the MNC-containing layer to exit the first stage <NUM> via the first outlet port <NUM> for collection in an MNC collection container as an MNC product.

According to another alternative MNC collection procedure, the conventional MNC collection procedure is modified by adding a blood collection phase. The blood collection phase may either be a new first phase or may represent a modification to the plasma collection phase that begins a conventional MNC collection procedure.

If the MNC collection procedure is to begin with a blood collection phase, blood is drawn into the fluid processing assembly and directed to the red blood collection container rather than to the separation chamber <NUM>. The amount of blood collected in the red blood cell collection container may be based on the amount of red blood cells required to convey MNCs from the separation chamber <NUM> to the MNC collection container later in the procedure. For example, the amount of blood collected may be selected to include all of the required red blood cells, or a lesser amount may instead be collected.

Following the blood collection phase, the system <NUM> transitions to a plasma collection phase. During this phase, blood begins to flow into the first stage <NUM> of the separation chamber <NUM>, rather than flowing into the red blood cell collection container. The blood in the first stage <NUM> is separated into platelet-poor plasma, the MNC-containing layer, and red blood cells. The platelet-poor plasma and red blood cells are removed from the first stage <NUM> (via the first and second outlet ports <NUM> and <NUM>, respectively), while the MNC-containing layer builds up in the first stage <NUM>. The platelet-poor plasma is collected, while the red blood cells are returned to the blood source.

Alternatively, rather than beginning with a dedicated blood collection phase, the MNC collection procedure may instead begin with a modified plasma collection phase. During such a modified plasma collection phase, a first portion of blood is conveyed into the red blood cell collection container while a second portion of the blood is simultaneously conveyed into the first stage <NUM> of the separation chamber <NUM>. The blood in the first stage <NUM> is separated, with platelet-poor plasma being conveyed out of the separation chamber <NUM> for collection and red blood cells being returned to the blood source, as in the plasma collection phase of the conventional MNC collection procedure. The percentages of blood being conveyed to the red blood cell collection and to the separation chamber <NUM> may be selected such that a suitable amount of blood is collected at the same time that a target amount of plasma has been collected. Alternatively, if blood collection is or would be completed prior to plasma collection or if plasma collection is or would be completed prior to blood collection, the percentages may be varied during this phase to complete both objectives (e.g., directing more or all drawn blood into the red blood cell collection container to complete blood collection or directing more or all drawn blood into the separation chamber <NUM> to complete plasma collection).

Once target amounts of blood and plasma have been collected, an MNC accumulation phase begins. During this phase, the position of the interface within the first stage <NUM> is moved closer to the low-G wall <NUM>, such that platelet-rich plasma and packed red blood cells are removed from the first stage <NUM> (via the first and second outlet ports <NUM> and <NUM>, respectively) while the MNC-containing layer continues to build up in the first stage <NUM>. Portions of the platelet-rich plasma and the packed red blood cells are returned to the blood source, with the remainder of the platelet-rich plasma and packed red blood cells being recirculated through the first stage <NUM> to maintain a proper hematocrit.

When a target or preselected amount of blood has been processed, the system <NUM> transitions to a red blood cell collection phase. During this phase, blood separation continues as in the MNC accumulation phase, with recirculation and return of the platelet-rich plasma continuing, while the separated red blood cells are conveyed from the first stage <NUM> and collected for later use rather than being recirculated or returned to the source. Rather than blood being drawn into the separation chamber <NUM> exclusively from the blood source, at least a portion of the blood entering the separation chamber <NUM> during this phase comes from the red blood cell collection container. If enough blood has been collected, then all of the blood conveyed into the separation chamber <NUM> may come from the red blood cell collection container. Alternatively, if a lesser amount of blood has been collected, then all of the blood from the red blood cell collection container may be conveyed into the separation chamber <NUM>, with an amount of blood from the blood source also being conveyed into the separation chamber <NUM>.

As described above, a modified MNC collection procedure may be advantageous to minimize the impact of mid-procedure termination. However, if the blood source cannot tolerate a modified MNC collection procedure of the type described herein, then a conventional MNC collection procedure must be carried out. In this case, the controller of the system <NUM> may be programmed with techniques that allow for at least partial MNC collection in the event that the procedure is terminated before the red blood cell collection phase is completed. Such techniques may involve salvaging red blood cells or red blood cell-containing from within the fluid processing assembly to collect all or a portion of the red blood cells required to harvest the MNCs. Alternatively, under certain circumstances, the fluid processing assembly may be converted to a different configuration for continued processing and MNC collection.

<FIG> shows a fluid processing assembly <NUM> that may be used in carrying out the MNC collection procedures and techniques described herein. The illustrated fluid processing assembly <NUM> has a "two needle" configuration, which includes a pair of fluid source access devices <NUM> and <NUM> (e.g., phlebotomy needles) configured for direct connection to a fluid source. The fluid source access devices <NUM> and <NUM> are connected by tubing <NUM> and <NUM> (referred to herein as a draw line and a return line, respectively) to a first or left cassette 112a. One of the fluid source access devices <NUM> is used to draw fluid (e.g., blood in an MNC collection procedure) from the fluid source into the fluid processing assembly <NUM> and is connected to the left cassette 112a through a y-connector <NUM>. The other leg of the y-connector <NUM> is connected to tubing <NUM> which leads to a second or middle cassette 112b. The tubing <NUM> is connected, through the middle cassette 112b, to additional tubing <NUM>, which includes a container access device <NUM> (e.g., a sharpened cannula or spike connector) for accessing the interior of a container, which may be an anticoagulant container in the case of a blood treatment operation. During a blood treatment operation (e.g., an MNC collection procedure), anticoagulant from the anticoagulant container is added to the blood from the fluid source at the y-connector <NUM> prior to entering the left cassette 112a.

The other fluid source access device <NUM> is used to deliver or return the original drawn fluid, a component of that fluid, and/or some other fluid to the fluid source and is also connected to the left cassette 112a through a y-connector <NUM>. The other leg of the y-connector <NUM> is connected to tubing <NUM> in fluid communication at its other end with a container access device <NUM>. Although not illustrated, the container access device <NUM> may be associated with a container having an amount of fluid (e.g., saline) to be used to prime the fluid processing assembly <NUM> and/or delivered to the fluid source via the fluid source access device <NUM>.

The left cassette 112a is also connected to tubing <NUM> in fluid communication with the separation chamber <NUM>, which separates the fluid into its constituent parts and returns the fluid components to the fluid processing assembly <NUM>, as described above. One of the fluid components (which may be separated red blood cells in an MNC collection procedure) is conveyed to the middle cassette 112b from the separation chamber <NUM> via tubing <NUM>, while another separated component (which may be a plasma constituent in an MNC collection procedure) is conveyed to a third or right cassette 112c of the fluid processing assembly <NUM> from the separation chamber <NUM> via tubing <NUM>. The first separated component (e.g., red blood cells) may be pumped to the left cassette 112a via tubing <NUM>, where it is returned to the fluid source, or may instead exit the middle cassette 112b via tubing <NUM> to a collection container <NUM> (referred to as a red blood cell collection container, in the context of a blood separation procedure) for storage or later use or may be recirculated from the middle cassette 112b through the separation chamber <NUM>, as described above. The second separated component (e.g., the plasma constituent) may be pumped back to the left cassette 112a via tubing <NUM> for return to the fluid source and/or it may be pumped into a collection container <NUM> (referred to as a plasma collection container, in the context of a blood separation procedure) via different tubing <NUM> or recirculated from the right cassette 112c through the separation chamber <NUM>, as described above. The destination of the various fluids passing through the cassettes depends upon the actuation of the various valves of the cassettes, as described in greater detail in <CIT>.

Each illustrated cassette <NUM> includes an injection-molded body that is compartmentalized by an interior wall to present or form a topside (which faces away from the fluid processing system <NUM>, during use) and an underside (which faces toward the fluid processing system <NUM>, during use). A flexible diaphragm overlies and peripherally seals the underside of each cassette <NUM>, while a generally rigid upper panel overlies the topside of each cassette <NUM> and is sealed peripherally and to raised, channel-defining walls in the cassette <NUM>.

The top- and undersides of the cassettes <NUM> contain preformed cavities. On the underside of the cassettes <NUM>, the cavities form an array of valve stations and an array of pressure sensing stations. On the topside of the cassettes <NUM>, the cavities form an array of channels or paths for conveying fluids. The valve stations communicate with the flow paths through the interior wall to interconnect them in a predetermined manner. The sensing stations also communicate with the flow paths through the interior wall to sense pressures in selected regions. The number and arrangement of the flow paths, the valve stations, and the sensing stations can vary without departing from the scope of the present disclosure.

In the illustrated embodiment, ten pre-molded tube connectors extend out along opposite side edges of each cassette <NUM>. The tube connectors are arranged five on one side edge and five on the other side edge. The other side edges of the cassettes <NUM>, as illustrated, are free of tube connectors. The tube connectors are associated with external tubing to associate the cassettes <NUM> with the remainder of the fluid processing assembly (e.g., to a plasma collection container <NUM>, an MNC collection container <NUM>, or a red blood cell collection container <NUM>) or to define tubing loops <NUM> that interact with pumps <NUM> of the fluid processing system <NUM> to flow fluid through the flow processing assembly <NUM>, as described in greater detail in <CIT>.

The tube connectors communicate with various interior flow paths, which constitute the flow paths of the cassettes <NUM> through which a fluid enters or exits the cassette <NUM>. The remaining interior flow paths of the cassette <NUM> constitute branch paths that link the flow paths associated with the tube connectors to each other through the valve stations and sensing stations. The particular configuration of one suitable cassette is described in greater detail in <CIT>.

The fluid processing assembly <NUM> may also include a number of other components, including clamps or valves and a drip chamber <NUM> that fluid passes through before entering the separation chamber <NUM>. The draw and return lines <NUM> and <NUM> are illustrated with pairs of connectors for converting the fluid processing assembly <NUM> from the "double needle" configuration of <FIG> to one of the "single needle" configurations of <FIG> and <FIG>, as will be described in greater detail herein.

Depending on the current phase when an MNC collection procedure is terminated, blood drawn into the fluid processing assembly <NUM> may be positioned between the draw line <NUM> and the separation chamber <NUM>. In particular, the blood may be positioned within the left cassette 112a, the drip chamber <NUM>, and in associated tubing. In this case, the controller of the fluid processing system <NUM> may actuate various pumps and valves to direct the blood in the left cassette 112a and/or the drip chamber <NUM> to the red blood cell collection container <NUM> instead of to its original destination (i.e., the separation chamber <NUM>). The controller may then advance the procedure to the next appropriate phase, with the blood in the red blood cell collection container <NUM> (and, optionally, separated red blood cells previously conveyed into the red blood cell collection container <NUM>) being conveyed into the separation chamber <NUM>.

If the procedure is terminated during an earlier phase (namely, before the red blood cell collection phase), the salvaged blood from the red blood cell collection container <NUM> may be separated to accumulate additional MNCs in the separation chamber <NUM>, with red blood cells separated from the blood being collected for later harvesting MNCs. If the procedure is terminated later (i.e., during the red blood cell collection phase), then red blood cells separated from the salvaged blood (along with any separated red blood cells already present in the red blood cell collection container <NUM>) may be used to collect MNCs as part of a modified MNC harvest phase.

According to a variation of the preceding recovery protocol, the controller of the fluid processing system <NUM> may instead actuate various pumps and valves to convey blood in the fluid processing assembly <NUM> (e.g., in the left cassette 112a or in the drip chamber <NUM>) directly into the separation chamber <NUM> immediately following mid-procedure termination, rather than first directing it to the red blood cell collection container <NUM>. The controller may additionally or alternatively (depending on the current phase when the MNC collection procedure is terminated) actuate various pumps and valves to convey separated red blood cells in the left and/or middle cassettes 112a and 112b into the separation chamber <NUM>. As necessary, the controller may actuate various pumps and valves to draw saline into the fluid processing assembly <NUM> from a saline container (not illustrated) to convey the blood and/or separated red blood cells to the separation chamber <NUM>.

When the blood and/or red blood cells have been conveyed into the separation chamber <NUM>, the controller may then advance the procedure to the next appropriate phase. If the procedure is terminated during an earlier phase (namely, before the red blood cell collection phase), any salvaged blood may be separated to accumulate additional MNCs in the separation chamber <NUM>, with red blood cells separated from the blood being collected for later harvesting MNCs. If the procedure is terminated later (i.e., during the red blood cell collection phase), then any salvaged red blood cells and/or red blood cells separated from the salvaged blood (along with any separated red blood cells already present in the red blood cell collection container <NUM>) may be used to collect MNCs as part of a modified MNC harvest phase.

This and the preceding recovery protocol may both be programmed into a controller, with the controller selecting one of the protocols depending on any of a variety of factors, such as the nature of the disruption leading to process termination and the current phase at the time of termination.

One possible disruption to an MNC collection procedure (or any other procedure employing a fluid processing system <NUM> and fluid processing assembly <NUM> of the type described herein) renders one of the draw and return lines <NUM> and <NUM> inoperative (e.g., due to a blockage), while the other line remains viable. In this case, following termination, the incapacitated line may be directly connected to the viable line, with the procedure then continuing (in some capacity) with the fluid processing assembly <NUM> in a "single needle" configuration instead of a "double needle" configuration. <FIG> and <FIG> illustrate two possible "single needle" configurations into which the fluid processing assembly <NUM> may be converted from its initial "double needle" configuration of <FIG>.

In the configuration of <FIG>, the return line <NUM> has been rendered inoperative, so it is directly connected to the draw line <NUM> for continued processing. The draw line <NUM> and return line <NUM> are provided with mating connectors <NUM> and <NUM> that are directly connected to convert the fluid processing assembly <NUM> from a "double needle" configuration to a "single needle" configuration in which the draw line <NUM> is responsible for both fluid draw and return. In the illustrated embodiment, the connector <NUM> of the draw line <NUM> is a configured as a female luer, while the connector <NUM> on the return line <NUM> is configured as a male luer, but the exact configuration of the mating connectors <NUM> and <NUM> may vary without departing from the scope of the present disclosure.

In the configuration of <FIG>, the draw line <NUM> has been rendered inoperative, so it is directly connected to the return line <NUM> for continued processing. The draw line <NUM> and return line <NUM> are provided with mating connectors <NUM> and <NUM> that are directly connected to convert the fluid processing assembly <NUM> from a "double needle" configuration to a "single needle" configuration in which the return line <NUM> is responsible for both fluid draw and return. In the illustrated embodiment, the connector <NUM> of the draw line <NUM> is a configured as a male luer, while the connector <NUM> on the return line <NUM> is configured as a female luer, but the exact configuration of the mating connectors <NUM> and <NUM> may vary without departing from the scope of the present disclosure.

In general, a "single needle" procedure may include the same phases as a corresponding "double needle" procedure, but may require additional phases or sub-phases to account for the single access point to the fluid source. While a "double needle" configuration allows for simultaneous fluid draw and return, a "single needle" configuration requires alternating fluid draw and return via the single access line. Thus, when executing an MNC collection procedure using a fluid processing assembly <NUM> in a "single needle" configuration, the same phases of the above-described "double needle" configuration are carried out, but blood draw will be periodically suspended to allow for separated fluid components and/or other fluid (e.g., saline or another replacement fluid) to be conveyed to the blood source. The fluid processing assembly <NUM> may be provided with a return container <NUM> that is unused in the "double needle" configuration, but which provides a temporary reservoir for separated fluid components during blood draw of a "single needle" procedure, with the contents of the return container <NUM> subsequently being conveyed to the blood source during a return phase or sub-phase.

The processing following conversion from a "double needle" configuration to a "single needle" configuration may vary depending on a number of factors, including: the current procedure state or phase at the time of termination, the amount of fluid processed at the time of termination, the amount of fluid currently present in the fluid processing assembly <NUM> at the time of termination, and current fluid balance. The controller of the fluid processing system <NUM> may monitor at least one of these factors (and/or some other appropriate factor) and use that information to determine how to proceed once processing is unpaused. Depending on the circumstances, the controller may determine that it is appropriate to continue the procedure state or phase that was being executed at the time of termination. If the controller instead determines that it would be inappropriate to continue with the procedure state or phase that was being executed at the time of termination, then it may instead initiate a different procedure state or phase, which may be the phase or procedure state immediately following the phase or procedure state that was being executed at the time of termination, a variation of such succeeding phase or procedure state, or some other phase or procedure state.

For example, according to one approach, the fluid processing assembly <NUM> is disconnected from the fluid source upon mid-processing termination of an MNC collection procedure and converted from a "double needle" configuration into a "single needle" configuration, with the single access line (i.e., either the draw line <NUM> in the configuration of <FIG> or the return line <NUM> in the configuration of <FIG>) being connected to a saline container. When a system operator or technician confirms that the fluid processing assembly <NUM> has been successfully converted to a "single needle" configuration, the controller may unpause processing by initiating a phase or procedure state in which saline is drawn into the fluid processing assembly <NUM> via the access line and used to convey blood and/or separated red blood cells in the fluid processing assembly <NUM> (e.g., in the draw and/or return lines <NUM> and <NUM>, in the left cassette 112a, and/or in the middle cassette 112b) to the separation chamber <NUM>. The blood conveyed into the separation chamber <NUM> may be used to accumulate an additional amount of MNCs within the separation chamber <NUM>, while the red blood cells separated from the salvaged blood, along with the salvaged red blood cells conveyed into the separation chamber <NUM>, may be directed out of the separation chamber <NUM> to the red blood cell collection container <NUM> for later use in harvesting MNCs.

It should be understood that the preceding is only one exemplary approach to continuing a terminated MNC collection procedure, and that other approaches may also be employed without departing from the scope of the present disclosure. <FIG> and <FIG> show one exemplary manner (not according to the invention) in which the system controller may be programmed with possible options for proceeding with a terminated procedure (which may include permanent termination of the procedure), depending on the current phase or procedure state being executed at the time of termination. As shown in <FIG> and <FIG>, converting the fluid processing assembly <NUM> from a "double needle" configuration to a "single needle" configuration is only one possible approach to mid-processing termination, but may be advantageous for a relatively early termination, as it allows for completion (or at least substantial completion) of the intended procedure, whereas other approaches may result in a truncated version of the intended procedure.

For example, if processing is terminated during a "collection" procedure state, the controller has four options for proceeding. The first option is to continue the "collection" procedure state with the fluid processing assembly <NUM> in a "single needle" configuration instead of its initial "double needle" configuration. Once the operator or technician has converted the fluid processing assembly <NUM>, the "collection" procedure state resumes in a "single needle" variation of the terminated "double needle" procedure state, with the procedure ultimately being completed with the fluid processing assembly <NUM> in a "single needle" configuration. If the controller determines that conversion is not an option (or if the operator or technician instructs the controller to not proceed with conversion), then the controller may either terminate the procedure without reinfusion (which ends the procedure), terminate the "collection" procedure state and perform reinfusion (which eliminates "transfer" and "photoactivation" procedure states), or terminate the partially completed "collection" procedure state and proceed with the succeeding "transfer" procedure state. As described above, the particular approach selected or recommended by the system controller may depend on one or more factors that are monitored by the controller during processing.

Similarly, if processing is terminated during a "transfer" procedure state, the controller has four options for proceeding. The first option is to continue the "transfer" procedure state with the fluid processing assembly <NUM> in a "single needle" configuration instead of its initial "double needle" configuration. Once the operator or technician has converted the fluid processing assembly <NUM>, the "transfer" procedure state resumes in a "single needle" variation of the terminated "double needle" procedure state (including the option of performing additional "collection" phases), with the procedure ultimately being completed with the fluid processing assembly <NUM> in a "single needle" configuration. If the controller determines that conversion is not an option (or if the operator or technician instructs the controller to not proceed with conversion), then the controller may either terminate the procedure without reinfusion (which ends the procedure), terminate the "transfer" procedure state and perform reinfusion (which eliminates a "photoactivation" procedure state), or continue the "transfer" procedure state without the option of performing additional "collection" phases.

Claim 1:
A fluid processing assembly (<NUM>) configured for use in combination with a fluid processing system (<NUM>), comprising:
a separation chamber (<NUM>) configured to separate a fluid into two or more fluid components and including an inlet flow path and an outlet flow path;
a draw line (<NUM>) in fluid communication with the inlet flow path and configured for direct connection to a source to draw a fluid from the source into the fluid processing assembly (<NUM>); and
a return line (<NUM>) in fluid communication with the outlet flow path and configured for direct connection to the source to convey a replacement fluid and/or at least a portion of a separated fluid component to the source, wherein
the draw line (<NUM>) includes a first connector (<NUM>),
the return line (<NUM>) includes a second connector (<NUM>) configured to be connected to the first connector (<NUM>), and
connecting the first and second connectors (<NUM>, <NUM>) removes one of the draw and return lines (<NUM>, <NUM>) from direct connection to the source while placing the other one of the draw and return lines (<NUM>, <NUM>) into condition for drawing fluid from the source into the fluid processing assembly (<NUM>) and conveying a replacement fluid and/or at least a portion of a separated fluid component to the source.