Surgery – Blood drawn and replaced or treated and returned to body – Constituent removed from blood and remainder returned to body
Reexamination Certificate
2001-03-09
2004-05-04
Sykes, Angela D. (Department: 3762)
Surgery
Blood drawn and replaced or treated and returned to body
Constituent removed from blood and remainder returned to body
C604S006010, C604S006110, C210S782000
Reexamination Certificate
active
06730055
ABSTRACT:
FIELD OF THE INVENTION
The present invention generally relates to the field of extracorporeal blood processing and, more particularly, to methods and apparatus which may be incorporated into an apheresis system useful for blood component collection, or for therapeutic purposes.
BACKGROUND OF THE INVENTION
One type of extracorporeal blood processing is an apheresis procedure in which blood is removed from a donor or patient (hereafter, donor/patient), directed to a blood component separation device (e.g., centrifuge), and separated into various blood component types (e.g., red blood cells, white blood cells, platelets, plasma) for collection and/or therapeutic purposes. One or more of these blood component types are collected (e.g., for therapeutic transfusion purposes), while the remainder are preferably returned to the donor or donor/patient.
A number of factors may affect the commercial viability of an apheresis system. One factor relates to the operator of the system, specifically the time and/or expertise required of an individual to prepare and operate the apheresis system. For instance, reducing the time required by the operator to load and unload the disposables, as well as the complexity of these actions, can increase productivity and/or reduce the potential for operator error. Moreover, reducing the dependency of the system on the operator may lead to reductions in operator errors and/or to reductions in the credentials desired/required for the operators of these systems.
Donor-related factors may also impact the commercial viability of an apheresis system and include donor convenience and donor comfort. For instance, donors typically have a limited amount of time which may be committed to visiting a blood component collection facility for a donation. Consequently, once at the collection facility the amount of the donor's time which is actually spent collecting blood components is another factor which should be considered. This also relates to donor comfort in that many view the actual collection procedure as being somewhat discomforting in that at least one and sometimes two access needles are disposed in the donor throughout the procedure.
Performance-related factors continue to affect the commercial viability of an apheresis system. Performance may be judged in terms of the “collection efficiency” of the apheresis system, which may in turn reduce the amount of donation time and thus increase donor convenience. The “collection efficiency” of a system may of course be gauged in a variety of ways, such as by the amount of a particular blood component type which is collected in relation to the quantity of this blood component type which passes through the apheresis system. Performance may also be evaluated based upon the effect which the apheresis procedure has on the various blood component types. For instance, it is desirable to minimize the adverse effects on the blood component types as a result of the apheresis procedure (e.g., reduce platelet activation).
SUMMARY OF THE INVENTION
The present invention generally relates to extracorporeal blood processing. Since each of the various aspects of the present invention may be incorporated into an apheresis system (e.g., whether for blood component collection in which “healthy” cells and/or plasma are removed from the blood or for therapeutic purposes in which “unhealthy” cells and/or plasma are removed from the blood), the present invention will be described in relation to this particular application. However, at least certain of the aspects of the present invention may be suited for other extracorporeal blood processing applications and such are also within the scope of the present invention.
A typical apheresis system which may embody one or more aspects of the present invention would generally include a blood component separation device; for example, a membrane-based separation device and/or, a rotatable centrifuge element, such as a rotor, which provides the forces required to separate blood into its various blood component types (e.g., red blood cells, white blood cells, platelets, and/or plasma). In one preferred embodiment, the separation device includes a channel which receives a blood processing vessel. Typically, a healthy human donor or a donor/patient suffering from some type of illness (collectively referred to here as a donor/patient) is fluidly interconnected with the blood processing vessel by an extracorporeal tubing circuit, and preferably the blood processing vessel and extracorporeal tubing circuit collectively define a closed, sterile system. When the fluid interconnection is established, blood may be extracted from the donor/patient and directed to the blood component separation device such that at least one type of blood component may be separated and removed from the blood, either for collection or for therapy.
When the blood processing vessel is loaded into the channel, the blood processing vessel and most of the tubing lines must be primed. In this regard, an aspect of the present invention relates to priming these elements, preferably with blood. A channel associated with a channel housing, which is rotatably interconnected with a centrifuge rotor, preferably includes a first cell separation stage. The channel extends generally curvilinearly about a rotational axis of the channel housing in a first direction. The channel preferably includes, progressing in the first direction, the first cell separation stage, a red blood cell dam, a platelet and/or a plasma collection area, and an interface control region for controlling a radial position of at least one interface between red blood cells (RBCs) and an adjacent blood component type(s) (e.g., plasma and/or a buffy coat of white blood cells (WBCs), lymphocytes, and platelets). Blood introduced into the channel is separated into layers of red blood cells (and/or a buffy coat generally including white blood cells and platelets), and plasma in the first cell separation stage. Preferably, throughout an RBC/plasma apheresis procedure (e.g., a non-platelet procedure) and including the priming of the blood processing vessel, only separated plasma flows beyond the red blood cell dam where the plasma may be removed from the channel in the plasma collection area. This is provided by an interface control mechanism which is disposed in the interface control region of the channel and which maintains the position of the interface between separated red blood cells and the plasma such that this condition is maintained. Note, the buffy coat (platelets and WBCs) is also preferably kept behind the RBC dam in the RBC/plasma collection procedures. In this embodiment, the buffy coat is generally collected with the RBCs and may be either later filtered out (e.g., the WBCs by leukoreduction filtration) or left in the RBC product (the platelets).
Although the term “blood prime” may be subject to a variety of characterizations, in each case described herein, blood is the first fluid introduced into the blood processing vessel. One characterization of the blood prime is that separated plasma is provided to the interface control region before any separated red blood cells would ever flow beyond the red blood cell dam into the plasma collection area. Preferably, no RBCs ever flow over the RBC dam. Another characterization is that blood and/or blood component types occupy the entire fluid-containing volume of the blood processing vessel before any separated red blood cells would flow beyond the red blood cell dam into the plasma collection area.
A further aspect of the present invention relates to blood priming an apheresis system which includes a channel housing having a blood processing channel associated therewith, a blood processing vessel disposed in the channel and which has a blood inlet port and a red blood cell (RBC) outlet port which also acts as an interface control port. The RBC/interface control port is used to control the radial position of at least one interface between separated red blood cells and a blood component type(s), here preferably plasma, dispo
Bainbridge Marlene
Butzke Scott D.
Gordon Timothy M.
Keller Muriel
McAteer Michael J.
Deak Leslie
Gambro Inc.
Merkling John R.
Scull Peter B.
Sykes Angela D.
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