CROSS-REFERENCED TO RELATED APPLICATIONSThis application is a Divisional of U.S. patent application Ser. No. 09/832,711, filed Apr. 9, 2001, the entire content of which is specifically incorporated herein by reference.
1. Field of the Invention
This invention relates to novel methods, devices and apparatuses for the centrifugal separation of a liquid into its components of varying specific gravities, and is more particularly directed toward a blood separation device useful, for example, in the separation of blood components for use in various therapeutic regimens.
2. Description of the State of Art
Centrifugation utilizes the principle that particles suspended in solution will assume a particular radial position within the centrifuge rotor based upon their respective densities and will therefore separate when the centrifuge is rotated at an appropriate angular velocity for an appropriate period of time. Centrifugal liquid processing systems have found applications in a wide variety of fields. For example, centrifugation is widely used in blood separation techniques to separate blood into its component parts, that is, red blood cells, platelets, white blood cells, and plasma.
The liquid portion of the blood, referred to as plasma, is a protein-salt solution in which red and white blood cells and platelets are suspended. Plasma, which is 90 percent water, constitutes about 55 percent of the total blood volume. Plasma contains albumin (the chief protein constituent), fibrinogen (responsible, in part, for the clotting of blood), globulins (including antibodies) and other clotting proteins. Plasma serves a variety of functions, from maintaining a satisfactory blood pressure and providing volume to supplying critical proteins for blood clotting and immunity. Plasma is obtained by separating the liquid portion of blood from the cells suspended therein.
Red blood cells (erythrocytes) are perhaps the most recognizable component of whole blood. Red blood cells contain hemoglobin, a complex iron-containing protein that carries oxygen throughout the body while giving blood its red color. The percentage of blood volume composed of red blood cells is called the “hematocrit.”
White blood cells (leukocytes) are responsible for protecting the body from invasion by foreign substances such as bacteria, fungi and viruses. Several types of white blood cells exist for this purpose, such as granulocytes and macrophages, which protect against infection by surrounding and destroying invading bacteria and viruses, and lymphocytes, which aid in the immune defense.
Platelets (thrombocytes) are very small cellular components of blood that help the clotting process by sticking to the lining of blood vessels. Platelets are vital to life, because they help prevent both massive blood loss resulting from trauma and blood vessel leakage that would otherwise occur in the course of normal, day-to-day activity.
If whole blood is collected and prevented from clotting by the addition of an appropriate anticoagulant, it can be centrifuged into its component parts. Centrifugation will result in the red blood cells, which weigh the most, packing to the most outer portion of the rotating container, while plasma, being the least dense will settle in the central portion of the rotating container. Separating the plasma and red blood cells is a thin white or grayish layer called the buffy coat. The buffy coat layer consists of the white blood cells and platelets, which together make up about 1 percent of the total blood volume.
These blood components, discussed above, may be isolated and utilized in a wide range of diagnostic and therapeutic regimens. For example, red blood cells are routinely transfused into patients with chronic anemia resulting from disorders such as kidney failure, malignancies, or gastrointestinal bleeding and those with acute blood loss resulting from trauma or surgery. The plasma component is typically frozen by cryoprecipitation and then slowly thawed to produce cryoprecipitated antihemophiliac factor (AHF), which is rich in certain clotting factors, including Factor VRI, fibrinogen, von Willebrand factor and Factor XIII. Cryoprecipitated AHF is used to prevent or control bleeding in individuals with hemophilia and von Willebrand's disease. Platelets and white blood cells, which are found in the buffy layer component, can be used to treat patients with abnormal platelet function (thrombocytopenia) and patients that are unresponsive to antibiotic therapy, respectively.
Various techniques and apparatus have been developed to facilitate the collection of whole blood and the subsequent separation of therapeutic components therefrom. Centrifugal systems, also referred to as blood-processing systems, generally fall into two categories, discontinuous-flow and continuous-flow devices.
In discontinuous-flow systems, whole blood from the donor or patient flows through a conduit into the rotor or bowl where component separation takes place. These systems employ a bowl-type rotor with a relatively large (typically 200 ml or more) volume that must be filled with blood before any of the desired components can be harvested. When the bowl is full, the drawing of fresh blood is stopped, the whole blood is separated into its components by centrifugation, and the unwanted components are returned to the donor or patient through the same conduit intermittently, in batches, rather than on a continuous basis. When the return has been completed, whole blood is again drawn from the donor or patient, and a second cycle begins. This process continues until the required amount of the desired component has been collected.
Discontinuous-flow systems have the advantage that the rotors are relatively small in diameter but have the disadvantage that the extracorporeal volume (i.e., the amount of blood that is out of the donor at any given time during the process) is large. This, in turn, makes it difficult or impossible to use discontinuous systems on people whose size and weight will not permit the drawing of the amount of blood required to fill the rotor. Discontinuous-flow devices are used for the collection of platelets and/or plasma, and for the concentration and washing of red blood cells. They are used to reconstitute previously frozen red blood cells and to salvage red blood cells lost intraoperatively. Because the bowls in these systems are rigid and have a fixed volume, however, it is difficult to control the hematocrit of the final product, particularly if the amount of blood salvaged is insufficient to fill the bowl with red blood cells.
One example of a discontinuous-flow system is disclosed by McMannis, et al., in his U.S. Pat. No. 5,316,540, and is a variable volume centrifuge for separating components of a fluid medium, comprising a centrifuge that is divided into upper and lower chambers by a flexible membrane, and a flexible processing container bag positioned in the upper chamber of the centrifuge. The McMannis, et al., system varies the volume of the upper chamber by pumping a hydraulic fluid into the lower chamber, which in turn raises the membrane and squeezes the desired component out of the centrifuge. The McMannis; et al., system takes up a fairly large amount of space, and its flexible pancake-shaped rotor is awkward to handle. The McMannis, et al., system does not permit the fluid medium to flow into and out of the processing bag at the same time, nor does it permit fluid medium to be pulled out of the processing bag by suction.
In continuous-flow systems, whole blood from the donor or patient also flows through one conduit into the spinning rotor where the components are separated. The component of interest is collected and the unwanted components are returned to the donor through a second conduit on a continuous basis as more whole blood is being drawn. Because the rate of drawing and the rate of return are substantially the same, the extracorporeal volume, or the amount of blood that is out of the donor or patient at any given time in the procedure, is relatively small. These systems typically employ a belt-type rotor, which has a relatively large diameter but a relatively small (typically 100 mL or less) processing volume. Although continuous-flow systems have the advantage that the amount of blood that must be outside the donor or patient can be relatively small, they have the disadvantage that the diameter of the rotor is large. These systems are, as a consequence, large. Furthermore, they are complicated to set up and use. These devices are used almost exclusively for the collection of platelets.
Continuous-flow systems are comprised of rotatable and stationary parts that are in fluid communication. Consequently, continuous-flow systems utilize either rotary seals or a J-loop. A variety of types of rotary centrifuge seals have been developed. Some examples of rotary centrifuge seals which have proven to be successful are described in U.S. Pat. Nos. 3,409,203 and 3,565,330, issued to Latham. In these patents, rotary seals are disclosed which are formed from a stationary rigid low friction member in contact with a moving rigid member to create a dynamic seal, and an elastomeric member which provides a resilient static seal as well as a modest closing force between the surfaces of the dynamic seal.
Another rotary seal suitable for use in blood-processing centrifuges is described in U.S. Pat. No. 3,801,142 issued to Jones, et al. In this rotary seal, a pair of seal elements having confronting annular fluid-tight sealing surfaces of non-corrodible material are provided. These are maintained in a rotatable but fluid-tight relationship by axial compression of a length of elastic tubing forming one of the fluid connections to these seal elements.
Related types of systems, which incorporate rotatable, disposable annular separation chambers, coupled via rotary seals to stationary tubing members are disclosed in U.S. Pat. Nos. 4,387,848; 4,094,461; 4,007,871; and 4,010,894.
One drawback present in the above-described continuous-flow systems has been their use of a rotating seal or coupling element between that portion of the system carried by the centrifuge rotor and that portion of the system which remains stationary. While such rotating seals have provided generally satisfactory performance, they have been expensive to manufacture and have unnecessarily added to the cost of the flow systems. Furthermore, such rotating seals introduce an additional component into the system which if defective can cause contamination of the blood being processed.
One flow system heretofore contemplated to overcome the problem of the rotating seal utilizes a rotating carriage on which a single housing is rotatably mounted. An umbilical cable extending to the housing from a stationary point imparts planetary motion to the housing and thus prevents the cable from twisting. To promote the desired ends of sterile processing and avoid the disadvantages of a discontinuous-flow system within a single sealed system, a family of dual member centrifuges can be used to effect cell separation. One example of this type of centrifuge is disclosed in U.S. Pat. No. RE. 29,738 to Adams entitled “Apparatus for Providing Energy Communication Between a Moving and a Stationary Terminal.” As is now well known, due to the characteristics of such dual member centrifuges, it is possible to rotate a container containing a fluid, such as a unit of donated blood and to withdraw a separated fluid component, such as plasma, into a stationary container, outside of the centrifuge without using rotating seals. Such container systems utilize a J-loop and can be formed as closed, sterile transfer sets.
The Adams patent discloses a centrifuge having an outer rotatable member and an inner rotatable member. The inner member is positioned within and rotatably supported by the outer member. The outer member rotates at one rotational velocity, usually called “one omega,” and the inner rotatable member rotates at twice the rotational velocity of the outer housing or “two omega.” There is thus a one-omega difference in rotational speed of the two members. For purposes of this document, the term “dual member centrifuge” shall refer to centrifuges of the Adams type.
The dual member centrifuge of the Adams patent is particularly advantageous in that, as noted above, no seals are needed between the container of fluid being rotated and the non-moving component collection containers. The system of the Adams patent provides a way to process blood into components in a single, sealed, sterile system wherein whole blood from a donor can be infused into the centrifuge while the two members of the centrifuge are being rotated.
An alternate to the apparatus of the Adams patent is illustrated in U.S. Pat. No. 4,056,224 to Lolachi entitled “Flow System for Centrifugal Liquid Processing Apparatus.” The system of the Lolachi patent includes a dual member centrifuge of the Adams type. The outer member of the Lolachi centrifuge is rotated by a single electric motor which is coupled to the internal rotatable housing by belts and shafts.
U.S. Pat. No. 4,108,353 to Brown entitled “Centrifugal Apparatus With Oppositely Positioned Rotational Support Means” discloses a centrifuge structure of the Adams type which includes two separate electrical motors. One electric motor is coupled by a belt to the outer member and rotates the outer member at a desired nominal rotational velocity. The second motor is carried within the rotating exterior member and rotates the inner member at the desired higher velocity, twice that of the exterior member.
U.S. Pat. No. 4,109,855 to Brown, et al., entitled “Drive System For Centrifugal Processing Apparatus” discloses yet another drive system. The system of the Brown, et al., patent has an outer shaft, affixed to the outer member for rotating the outer member at a selected velocity. An inner shaft, coaxial with the outer shaft, is coupled to the inner member. The inner shaft rotates the inner member at twice the rotational velocity as the outer member. A similar system is disclosed in U.S. Pat. No. 4,109,854 to Brown entitled “Centrifugal Apparatus With Outer Enclosure.”
The continuous-flow systems described above are large and expensive units that are not intended to be portable. Further, they are also an order of magnitude more expensive than a standard, multi-container blood collection set. There exists the need, therefore, for a centrifugal system for processing blood and other biological fluids that is compact and easy to use and that does not have the disadvantages of prior-art continuous-flow systems.
Whole blood that is to be separated into its components is commonly collected into a flexible plastic donor bag, and the blood is centrifuged to separate it into its components through a batch process. This is done by spinning the blood bag for a period of about 10 minutes in a large refrigerated centrifuge. The main blood constituents, i.e., red blood cells, platelets and white cells, and plasma, having sedimented and formed distinct layers, are then expressed sequentially by a manual extractor in multiple satellite bags attached to the primary bag.
More recently, automated extractors have been introduced in order to facilitate the manipulation. Nevertheless, the whole process remains laborious and requires the separation to occur within a certain time frame to guarantee the quality of the blood components. This complicates the logistics, especially considering that most blood donations are performed in decentralized locations where no batch processing capabilities exist.
This method has been practiced since the widespread use of the disposable plastic bags for collecting blood in the 1970's and has not evolved significantly since then. Some attempts have been made to apply haemapheresis technology in whole blood donation. This technique consists of drawing and extracting on-line one or more blood components while a donation is performed, and returning the remaining constituents to the donor. However, the complexity and costs of haemapheresis systems preclude their use by transfusion centers for routine whole blood collection.
There have been various proposals for portable, disposable, centrifugal apparatus, usually with collapsible bags, for example as in U.S. Pat. No. 3,737,096, or 4,303,193 to Latham, Jr., or with a rigid walled bowl as in U.S. Pat. No. 4,889,524 to Fell, et al. These devices all have a minimum fixed holding volume which requires a minimum volume usually of about 250 ml to be processed before any components can be collected.
U.S. Pat. No. 5,316,540 to McMannis, et al., discloses a centrifugal processing apparatus, wherein the processing chamber is a flexible processing bag which can be deformed to fill it with biological fluid or empty it by means of a membrane which forms part of the drive unit. The bag comprises a single inlet/outlet tubing for the introduction and removal of fluids to the bag, and consequently cannot be used in a continual, on-line process. Moreover, the processing bag has a the disadvantage of having 650 milliliter capacity, which makes the McMannis, et al., device difficult to use as a blood processing device.
As discussed above, centrifuges are often used to separate blood into its components for use in a variety of therapeutic regimens. One such application is the preparation of a bioadhesive sealant. Bioadhesive sealants, also referred to as fibrin glues, are a relatively new technological advance which attempt to duplicate the biological process of the final stage of blood coagulation. Clinical reports document the utility of fibrin glue in a variety of surgical fields, such as, cardiovascular, thoracic, transplantation, head and neck, oral, gastrointestinal, orthopedic, neurosurgical, and plastic surgery. At the time of surgery, the two primary components comprising the fibrin glue, fibrinogen and thrombin, are mixed together to form a clot. The clot is applied to the appropriate site, where it adheres to the necessary tissues, bone, or nerve within seconds, but is then slowly reabsorbed by the body in approximately −10 days by fibrinolysis. Important features of fibrin glue is its ability to: (1) achieve haemostasis at vascular anastomoses particularly in areas which are difficult to approach with sutures or where suture placement presents excessive risk; (2) control bleeding from needle holes or arterial tears which cannot be controlled by suturing alone; and (3) obtain haemostasis in heparinized patients or those with coagulopathy. See, Borst, H. G., et al.,J. Thorac. Cardiovasc. Surg.,84:548-553 (1982); Walterbusch, G. J., et al,Thorac. Cardiovasc. Surg.,30:234-23 5 (1982); and Wolner, F. J., et al.,Thorac. Cardiovasc. Surg.,30:236-237 (1982).
Despite the effectiveness and successful use of fibrin glue by medical practitioners in Europe, neither fibrin glue nor its essential components fibrinogen and thrombin are widely used in the United States. In large part, this stems from the 1978 U.S. Food and Drug Administration ban on the sale of commercially prepared fibrinogen concentrate made from pooled donors because of the risk of transmission of viral infection, in particular the hepatitis-causing viruses such as HBV and HCV (also known as non-A and non-B hepatitis virus). In addition, the more recent appearance of other lipid-enveloped viruses such as HIV, associated with AIDS, cytomegalovirus (CMV), as well as Epstein-Barr virus and the herpes simplex viruses in fibrinogen preparations makes it unlikely that there will be a change in this policy in the foreseeable future. For similar reasons, human thrombin is also not currently authorized for human use in the United States. Bovine thrombin, which is licensed for human use in the United States, is obtained from bovine sources which do not appear to carry significant risks for HIV and hepatitis, although other bovine pathogens, such as bovine spongiform and encephalitis, may be present.
There have been a variety of methods developed for preparing fibrin glue. For example, Rose, et al. in U.S. Pat. No. 4,627,879 discloses a method of preparing a cryoprecipitated suspension containing fibrinogen and Factor XIII useful as a precursor in the preparation of a fibrin glue which involves (a) freezing fresh frozen plasma from a single donor such as a human or other animal, e.g. a cow, sheep or pig, which has been screened for blood transmitted diseases, e.g. one or more of syphilis, hepatitis or acquired immune deficiency syndrome, at about 80° C. for at least about 6 hours, preferably for at least about 12 hours; (b) raising the temperature of the frozen plasma, e.g. to between about 0° C. and room temperature, so as to form a supernatant and a cryoprecipitated suspension containing fibrinogen and Factor XIII; and (c) recovering the cryoprecipitated suspension. The fibrin glue is then prepared by applying a defined volume of the cyroprecipitate suspension described above and applying a composition containing a sufficient amount of thrombin, e.g. human, bovine, ovine or porcine thrombin, to the site so as to cause the fibrinogen in the suspension to be converted to the fibrin glue which then solidifies in the form of a gel.
A second technique for preparing fibrin glue is disclosed by Marx in his U.S. Pat. No. 5,607,694. Essentially, a cryoprecipitate as discussed previously serves as the source of the fibrinogen component and then Marx adds thrombin and liposomes. A third method discussed by Berruyer, M., et al., (J. Thorac. Cardiovasc. Surg.,105(5):892-897 (1992)) discloses a fibrin glue prepared by mixing bovine thrombin not only with human coagulant proteins, such as fibrinogen, fibronectin, Factor XII, and plasminogen, but also with bovine aprotinin and calcium chloride.
The above patents by Rose, et al. and Marx, and the technical paper by Berruyer, et al. each disclose methods for preparing fibrin sealants; however, each of these methods suffer disadvantages associated with the use of bovine thrombin as the activating agent. A serious and life threatening consequence associated with the use of fibrin glues comprising bovine thrombin is that patients have been reported to have a bleeding diathesis after receiving topical bovine thrombin. This complication occurs when patients develop antibodies to the bovine factor V in the relatively impure bovine thrombin preparations. These antibodies cross-react with human factor V, thereby causing a factor V deficiency that can be sufficiently severe to induce bleeding and even death. See, Rapaport, S. I., et al.,Am. J. Clin. Pathol.,97:84-91 (1992); Bermuyer, M., et al.J. Thorac. Cardiovasc. Surg.,105:892-897 (1993); Zehnder, J., et al.Blood,76(10):2011-2016 (1990); Muntean, W., et al.Acta Paediatr.,83:84-7 (1994); Christine, R. J., et al.Surgery,127:708-710 (1997).
A further disadvantage associated with the methods disclosed by Marx and Rose, et al. is that the cryoprecipitate preparations require a large amount of time and monetary commitment to prepare. Furthermore, great care must be taken to assure the absence of any viral contaminants.
A further disadvantage associated with the methods previously disclosed is that while human thrombin is contemplated for use as an activator, human thrombin is not available for clinical use and there is no evidence that patients will not have an antigenic response to human thrombin. By analogy, recombinant human factor VIII has been shown to produce antigenic responses in hemophiliacs. See, Biasi, R. de.,Thrombosis and Haemostasis,71(5):544-547 (1994). Consequently, until more clinical studies are performed on the effect of human recombinant thrombin one cannot merely assume that the use of recombinant human thrombin would obviate the antigenic problems associated with bovine thrombin. A second difficulty with thrombin is that it is autocatalytic, that is, it tends to self-destruct, making handling and prolonged storage a problem.
Finally, as discussed above, fibrin glue is comprised primarily of fibrinogen and thrombin thus lacking an appreciable quantity of platelets. Platelets contain growth factors and healing factors which are assumed to be more prevalent in a platelet concentrate. Moreover, platelets aid in acceleration of the clotting process.
There is still a need, therefore, for a centrifugal system for processing blood and other biological fluids, that is compact and easy to use and that does not have the disadvantages of prior-art continuous-flow systems and furthermore there exists a need for a convenient and practical method for preparing a platelet gel composition wherein the resulting platelet gel poses a zero risk of disease transmission and a zero risk of causing an adverse physiological reaction.
There is also a widespread need for a system that, during blood collection, will automatically separate the different components of whole blood that are differentiable in density and size, with a simple, low cost, disposable unit.
There is further a need for a centrifugal cell processing system wherein multiple batches of cells can be simultaneously and efficiently processed without the use of rotational coupling elements.
There is yet a further need for a platelet concentrate that aids in increasing the rate of fibrin clot formation, thereby facilitating haemostasis.
Preferably the apparatus will be essentially self-contained. Preferably, the equipment needed to practice the method will be relatively inexpensive and the blood contacting set will be disposable each time the whole blood has been separated.
Accordingly, one aspect of this invention provides a method and apparatus for the separation of components suspended or dissolved in a fluid medium by centrifugation. More specifically, one object of this invention is to provide a method for the separation and isolation of one or more whole blood components, such as platelet rich plasma, white blood cells and platelet poor plasma, from anticoagulated whole blood by centrifugation, wherein the components are isolated while the centrifuge is rotating.
Another aspect of this invention is to utilize the isolated cell components in a therapeutic regimen.
Another aspect of this invention provides an apparatus for the separation of whole blood components, wherein the apparatus contains a centrifuge bag that provides for simultaneous addition of whole blood from a source container and the withdrawal of a specific blood component during centrifugation.
Another aspect of this invention provides disposable, single-use centrifuge bags for holding whole blood during the separation of components of the whole blood by centrifugation, wherein the bag is adapted for use in a portable, point-of-use centrifuge.
Another aspect of this invention provides a portable centrifuge containing a disposable centrifuge bag that maximizes the amount of a predetermined blood fraction that can be harvested from an aliquot of blood that is of greater volume than the capacity of the disposable centrifuge bag.
More specifically, one embodiment of this invention comprises a flexible, disposable centrifuge bag adapted to be rotated about an axis, comprising:
a) one or more tubes, and
b) upper and lower flexible sheets, each sheet having a doughnut-shaped configuration, an inner perimeter defining a central core and an outer perimeter, wherein the upper and lower sheets are superimposed and completely sealed together at their outer perimeters, and wherein the tubes are sandwiched between the upper and lower sheets and extend from the central core toward the outer perimeter, such that when the upper and lower sheets are sealed at the inner perimeter the tubes are sealed between the upper and lower sheets at the inner perimeter and are in fluid communication with the environment inside and outside the centrifuge bag. The one or more tubes are fluidly connected to an umbilical cable comprising one or more lumen equal to the number of tubes of the centrifuge bag.
Yet another embodiment of the present invention comprises a rigid molded container adapted to be rotated about an axis, comprising a rigid, annular body having an axial core that is closed at the top end and opened at the bottom end. The rigid molded container further comprises an interior collection chamber for receiving and holding a fluid medium to be centrifuged, the chamber having an outer perimeter, an inner perimeter, and a generally off-centered “figure eight” shaped cross-sectional area. The rigid molded container further comprises a first channel which extends radially from the core and is in fluid communication with a point near the outer perimeter of the chamber, and a second channel which extends radially from the core and is in fluid communication with an area near the narrow portion or “neck” of the figure eight-shaped chamber. The first and second channels thus provide fluid communication with the environment inside and outside the interior collection chamber. The first and second channels are fluidly connected to a dual lumen tubing having an inlet lumen and an outlet lumen.
Yet another embodiment of the present invention is an apparatus and method for separating components contained in a fluid medium. More particularly, the present invention utilizes the principles of centrifugation to allow for the separation of whole blood into fractions such as platelet rich plasma and platelet poor plasma. In one aspect of the present invention, the above-described separation of the components is provided by utilizing a rotatable centrifuge motor comprising a base having a central column and a disposable centrifuge bag having a central core and which is positionable within the centrifuge motor and rotatable therewith. The disposable centrifuge bag, which holds the whole blood during centrifugation, further comprises an inlet tube for introducing the whole blood to the centrifuge bag, and an outlet tube for removing the desired blood fraction from the centrifuge bag. The inlet and outlet tubes are in fluid communication with a dual lumen tubing. The centrifuge bag is removably fixed within the centrifuge rotor by inserting the raised column through the bag center core and securing with the cover. During the rotation of the centrifuge, components of the whole blood will assume a radial, horizontal position within the centrifuge bag based upon a density of such components, and thus the fluid medium components will be separated from other components having different densities.
Once a desired degree of separation of whole blood has been achieved, the present invention provides for the specific removal of the desired fraction within one or more of the regions from the centrifuge bag through the outlet tube during continued rotation of the centrifuge, thereby allowing for on-line removal of the desired fraction. Additional aliquots may be added to the centrifuge bag via the inlet tube simultaneously or after the desired component has been harvested. In one embodiment, the centrifuge bag is a flexible, transparent, generally flat doughnut-shaped bag. In another embodiment, the centrifuge bag is a rigid, transparent container having an interior chamber for receiving and holding the fluid medium during centrifugation, the interior chamber having a generally off-centered figure eight cross-sectional configuration.
Another aspect of the present invention comprises a disposable centrifuge bag having an inlet tube and an outlet tube, wherein the outlet tube is fluidly connected with a bent fitting.
Another aspect of the present invention comprises a centrifuge rotor for holding a centrifuge bag, the rotor comprising a base and a cover, the base further having a first grooved, raised center column and the cover having a second grooved, raised center column. The centrifuge bag is a flexible, doughnut-shaped bag comprising inlet and outlet tubes in fluid communication with the environment inside and outside the centrifuge bag, wherein the tubes are seated in the base and cover column grooves to hold the centrifuge bag in a fixed position relative to the base and cover, such that the bag does not spin independently of the base and cover but rather spins concurrently and at the same rate of rotation as the base and cover.
Another aspect of the present invention comprises a centrifuge rotor for holding a centrifuge bag, the rotor comprising a base and a cover for securing a centrifuge bag therebetween, the centrifuge cover further comprising one or more concentric indicator circles that are spaced from the center of the cover or the base to aid the operator in visualizing the distal ends of these tubes.
Another aspect of the present invention for the separation of components of a fluid medium (e.g., whole blood) utilizes a centrifuge rotor comprising an interior chamber having a complex configuration, wherein the chamber holds a flexible, doughnut-shaped centrifuge bag for retaining the fluid medium during centrifugation. The centrifuge rotor is defined by a base having a lower chamber, and a cover having an upper chamber. When the cover is superimposed on the base, the upper and lower chambers define the annular interior chamber of the rotor. The interior rotor chamber has a generally off-centered figure eight-shaped cross-sectional configuration specifically designed to maximize the collection of the desired component (e.g., platelet rich plasma) by centrifugation of a fluid medium (e.g., anticoagulated whole blood). The centrifuge bag is formed from a substantially flexible material, such that the profile of the centrifuge bag during centrifugation is thus determined at least in part by the volume of the fluid medium contained therein. When the centrifuge bag is filled to maximum capacity, it assumes the configuration of the interior of the rotor chamber.
Another aspect of this invention comprises a method for on-line harvesting of a predetermined component of a fluid medium. One embodiment of the present invention utilizes a centrifuge and a disposable centrifuge bag for containing the fluid medium during separation and which is positionable within the centrifuge, the centrifuge bag further comprising at least one inlet tube and at least one outlet tube. The centrifuge includes a centrifuge rotor having a base portion, a cover, and an outer rim. The base portion and the cover define the interior of the centrifuge rotor, which is separated into upper and lower chambers. The disposable centrifuge bag is positionable horizontally within the lower chamber and may be appropriately secured to the centrifuge base by the cover. The centrifuge bag is fluidly connected via a dual lumen tubing to a source (e.g., to a container comprising anticoagulated autologous whole blood); and collection container (e.g., for receiving platelet rich plasma or some other component that will then be further processed). The dual lumen tubing comprises an inlet lumen fluidly connected to the inlet tube of the centrifuge bag and an outlet lumen fluidly connected to the outlet tube of the centrifuge bag. The centrifuge bag is substantially annular relative to the rotational axis of the centrifuge. When the centrifuge bag is positioned within the centrifuge rotor and appropriately secured thereto to allow for simultaneous rotation, the fluid medium may be provided to the centrifuge bag via the inlet lumen of the tubing during rotation of the centrifuge. The components of the bag assume radial, horizontal positions base based on their densities. When a desired degree of separation has been achieved, the desired fraction may be removed from the centrifuge bag via the outlet lumen during continued rotation of the centrifuge. The position of the fraction to be harvested may be shifted into the area of the outlet tube as needed, either by withdrawing components that are positioned near the outer perimeter through the inlet tube, or by adding additional aliquots of the fluid medium to the bag. In one embodiment of this method, the bag is a flexible, transparent doughnut-shaped bag. In another embodiment of this method, the bag is a rigid, transparent bag comprising an interior chamber having an off-entered, figure eight cross-sectional configuration.
This invention further provides a centrifugal liquid processing system that may be automated.
This invention further provides a centrifuge having an internal lead drive mechanism allowing for a compact size.
This invention further provides a method and device for the production and isolation of thrombin for all medical uses.
This invention further provides a method for preparing a completely autologous platelet gel.
This invention further provides an autologous platelet gel wherein the risks associated with the use of bovine and recombinant human thrombin are eliminated.
This invention further provides an autologous platelet gel for any application.
This invention further provides cellular components to be used in medical applications.
Additional advantages and novel features of this invention shall be set forth in part in the description and examples that follow, and in part will become apparent to those skilled in the art upon examination of the following or may be learned by the practice of the invention. The apects and the advantages of the invention may be further realized and attained by means of the instrumentalities and in combinations particularly pointed out in the appended claims.
The accompanying drawings, which are incorporated in and form a part of the specifications, illustrate embodiments of the present invention, and together with the description serve to explain the principles of the invention.
FIG. 1 is a perspective view illustrating one embodiment of the continuous-flow centrifugal processing system of the present invention illustrating a centrifuge and side-mounted motor positioned within a protective housing or enclosure of the invention.
FIG. 2 is an exploded side view of the centrifuge and the side-mounted motor of the centrifugal processing system ofFIG. 1 illustrating the individual components of the centrifuge.
FIG. 3 is a partial perspective view of the lower case assembly of the drive shaft assembly ofFIG. 2.
FIG. 4 is an exploded side view of the lower case assembly ofFIG. 3.
FIG. 5 is an exploded perspective view of the components of the lower case assembly ofFIG. 3.
FIG. 6 is a top view of the lower bearing assembly which is positioned within the lower case assembly ofFIG. 3.
FIG. 7 is a perspective view of the lower bearing assembly ofFIG. 6.
FIG. 8 is an exploded side view of the lower bearing assembly ofFIGS. 6 and 7.
FIG. 9 is a perspective view of the receiving tube guide of the centrifuge ofFIG. 2.
FIG. 10 is an exploded, perspective view of a gear of the mid-shaft gear assembly ofFIG. 2.
FIG. 11 is a perspective view of the gear ofFIG. 10 as it appears assembled.
FIG. 12 is an exploded, perspective view of the top bearing assembly of the centrifuge ofFIG. 2.
FIG. 13 is a perspective view of the top case shell of the top bearing assembly ofFIG. 12.
FIG. 14 is a perspective view of the centrifuge of the present invention shown inFIG. 1, having a quarter section cut away along lines14-14 ofFIG. 1.
FIG. 15 is a perspective view of one embodiment of a centrifuge rotor base.
FIG. 16 is a perspective view of one embodiment of a centrifuge rotor cover.
FIG. 17 is a side cross-sectional view of one embodiment of a rotor of this invention taken alongview lines17 ofFIG. 14 for holding a disposable centrifuge bag, showing a dual lumen tubing connected to the bag.
FIG. 18 is a side cross-sectional view of one embodiment of a rotor of this invention taken alongview lines18 ofFIG. 1 for holding a disposable centrifuge bag, showing the grooved columns of the base and cover.
FIG. 19 is an enlarged perspective view similar toFIG. 1 illustrating an alternate embodiment of a centrifuge driven by a side-mounted motor (with only the external drive belt shown).
FIG. 20 is a cutaway side view of the centrifuge ofFIG. 19 illustrating the internal pulley drive system utilized to achieve a desired drive ratio and illustrating the rotor base configured for receiving a centrifuge bag.
FIG. 21 is a cutaway side view similar toFIG. 20 with the rotor base removed to better illustrate the top pulley and the location of both idler pulleys relative to the installed internal drive belt.
FIG. 22 is a sectional view of the centrifuge ofFIG. 20 further illustrating the internal pulley drive system an showing the routing of the centrifuge tube (or umbilical cable).
FIG. 23 is a top view of a further alternate centrifuge similar to the centrifuge ofFIG. 19 but including internal, separate bearing members (illustrated as four cam followers) that allows the inclusion of guide shaft to be cut through portions of the centrifuge for positioning of the centrifuge tube (or umbilical cable).
FIG. 24 is a perspective view similar toFIG. 19 illustrating the centrifuge embodiment ofFIG. 23 further illustrating the guide slot and showing that the centrifuge can be driven by an external drive belt.
FIG. 25 is a top view of a flexible, disposable centrifuge bag of this invention.
FIG. 26 is a perspective view of a flexible, disposable centrifuge bag of this invention.
FIGS. 27,28,29, and30 are illustrations of bent fittings of this invention having “T” shaped, “curved T” shaped, “L” shaped, and “J” shaped configurations, respectively.
FIG. 31 is an illustration of an inlet and/or outlet tube of this invention.
FIG. 32 is a top view of a disposable centrifuge bag of this invention after the centrifugation of whole blood, showing the separated blood components.
FIGS. 33-39 are schematic illustrations of one method of this invention for separating whole blood components using a disposable centrifuge bag of this invention.
FIG. 40 is a top view of an alternate embodiment of a disposable centrifuge bag of the present invention having inner and outer chambers.
FIG. 41 is a top view of the disposable centrifuge bag shown inFIG. 34 illustrating movement of the red blood cell layer from the outer perimeter toward the inner perimeter.
FIG. 42 is a bottom view of an alternate embodiment of a disposable centrifuge bag of the present invention having inner and outer chambers in fluid communication with outlet and inlet ports.
FIG. 43 is a side cross-sectional view of a rigid disposable centrifuge bag of this invention.
FIG. 44 is a schematic illustration of separated blood components contained in a centrifuge bag having an elliptical cross-sectional view of the centrifuge bag shown inFIG. 43.
FIG. 45 is a side cross-sectional view of a rigid disposable centrifuge bag of this invention.
FIG. 46 is a schematic illustration of the surface areas and various dimensions of the figure eight configuration as shown inFIG. 45.
FIG. 47 is a schematic illustration of separated blood components contained in a centrifuge bag having a figure eight side cross-sectional configuration.
FIG. 48 is a side cross-sectional view of an alternative embodiment of an assembled centrifuge rotor of this invention comprising the rotor cover ofFIG. 49 and the rotor base ofFIG. 50.
FIG. 49 is a side cross-sectional view of an alternative embodiment of a rotor cover of this invention.
FIG. 50 is a side cross-sectional view of an alternative embodiment of a rotor base of this invention.
FIG. 51 is a perspective view of the rotor base ofFIG. 50.
FIG. 52 is a perspective view of the rotor cover ofFIG. 49.
FIG. 53 is a block diagram illustrating the components of a centrifugal processing system of the present invention.
FIG. 54 is a graph illustrating the timing and relationship of transmission of control signals and receipt of feedback signals during operation of one embodiment of the automated centrifugal processing system ofFIG. 53.
FIG. 55 is a side view of an alternative embodiment of the automated centrifugal processing system ofFIG. 53 showing a centrifuge having a rotor wherein the reservoir extends over the outer diameter of the centrifuge portion that facilitates use of an externally positioned sensor assembly.
FIG. 56 is a side view of a further alternative embodiment of the external sensor assembly feature of the centrifugal processing system of the invention without an extended rotor and illustrating the positioning of a reflector within the centrifuge.
FIG. 57 is a side view of yet another embodiment of the external sensor assembly feature of the centrifugal processing system of the invention illustrating a single radiant energy source and detector device.
FIG. 58 is a block diagram of a an automated centrifugal processing system, similar to the embodiment ofFIG. 47, including components forming a temperature control system for controlling temperatures of separated and processed products.
FIG. 59 is a perspective view of components of the temperature control system ofFIG. 58.
FIG. 60 is schematic and sectional view of the dispenser of the present invention.
FIG. 61 is a flow diagram representing the method for isolating platelet rich plasma and platelet poor plasma for use in preparing a platelet gel of the present invention.
FIG. 62 is a flow diagram representing the final portion of the method for preparing a platelet gel of the present invention using platelet rich plasma as a stating material.
FIG. 63 is a flow diagram representing the final portion of the method for preparing a platelet gel of the present invention using platelet poor plasma as a starting material.
FIG. 64 is a graphic representation of the effect that the serum-to-plasma ratio has on clotting times.
FIG. 65 graphically represents the effect of calcium addition on the clotting times of platelet rich plasma and platelet poor plasma.
FIG. 66 is a graphic representation of the relationship between clotting time and actual gel time using blood drawn from a donor.
FIG. 67 is a graphic representation of the relationship between clotting time and actual gel time using blood drawn from a donor.
FIG. 68 graphically represents the effect of calcium addition on clotting times and gel times using blood drawn from a donor.
FIG. 69 graphically represents the effect of calcium addition on clotting times and gel times using blood drawn from a donor.
Thecentrifugal processing system10 of the present invention is best shown inFIG. 1 having astationary base12, acentrifuge20 rotatably mounted to thestationary base12 for rotation about a predetermined axis A, arotor202 for receiving a disposable bag (not shown) designed for continuous-flow. As illustrated, thecentrifugal processing system10 includes aprotective enclosure11 comprising the main table plate orstationary base12,side walls13, and aremovable lid15 made of clear or opaque plastic or other suitable materials to provide structural support for components of thecentrifugal processing system10, to provide safety by enclosing moving parts, and to provide a portablecentrifugal processing system10. Thecentrifugal processing system10 further includes aclamp22 mounted over an opening (not shown) in thelid15.Clamp22 secures at a point at or proximately to axis A without pinching off the flow of fluid that travels throughumbilical cable228. A side mountedmotor24 is provided and connected to thecentrifuge20 by way of adrive belt26 for rotating the drive shaft assembly28 (seeFIG. 2) and the interconnected and drivenrotor assembly200 in the same rotational direction with a speed ratio selected to control binding ofumbilical cable228 during operation of the system, such as a speed ratio of 2:1 (i.e., therotor assembly200 rotates twice for each rotation of the drive shaft assembly28). The present invention is further directed toward adispensing device902, best shown inFIG. 60 for the withdrawal and manipulation of specific blood components for various therapeutic regimens, such as but not limited to the production of platelet rich plasma, platelet poor plasma, and white blood cells which may be used for the production of autologous thrombin and autologous platelet gels.
Referring now toFIG. 2, the continuous-flow centrifugal processing-system10 comprises acentrifuge20 to which arotor202 is removably or non-removably attached. The design ofcentrifuge20 and its self-contained mid-shaft gear assembly108 (comprised ofgears110,110′,131, and74) is a key component of the invention thereby allowing for the compact size of the entirecentrifugal processing system10 and providing for a desired speed ratio between thedrive shaft assembly28 and therotor assembly200.
Thecentrifuge20 is assembled, as best seen inFIG. 2, by inserting thelower bearing assembly66 intolower case shell32 thus resulting inlower case assembly30.Cable guide102 and gears110 and110′ are then positioned withinlower case assembly30, as will be discussed in more detail below, so that gears111 and110′ are moveably of engaged withlower bearing assembly66.Upper bearing assembly130 is then inserted withintop case shell126 thus resulting in bearingassembly124 which is then mated to lower case assembly,30, such that gears110 and110′ are also moveably engaged withupper bearing assembly130, and held in place byfasteners29.Lower bearing assembly66 is journaled to stationary base ormain table plate12 byscrews14, thus allowingcentrifuge20 to rotate along an axis A, perpendicular to main table plate12 (as shown inFIG. 1).
Referring now toFIGS. 3,4, and5, thelower case assembly30 is preferably, but not necessarily, machined or molded from a metal material and includes alower case shell32,timing belt ring46,timing belt flange50, and bearing62 (e.g., ball bearings and the like).Lower case shell32 includes an elongatedmain body40 with a smallerdiameter neck portion36 extending from one end of themain body40 for receivingtiming belt ring46 andtiming belt flange50. The larger diametermain body40 terminates into theneck portion36 thereby forming anexternal shoulder38 having a bearingsurface42 fortiming belt ring46. Timingbelt ring46 andtiming belt flange50, as best seen inFIG. 5, have inner diameters that are slightly larger than the outer diameter ofneck portion36 allowing both to fit overneck portion36.Shoulder38 further contains at least one and preferably four internally thread holes44 that align with hole guides48 and52 intiming belt ring46 andtiming belt flange50, respectively (shown inFIG. 5). Consequently, when assembled, screws54 are received by hole guides52 and48 and are threaded into thread holes44 thus securingtiming belt46 andtiming belt flange50 ontoneck portion36.Lower case shell32 also has an axial or sleeve bore56 extending there through, and aninternal shoulder58, theupper surface60 of which is in approximately the same horizontal plane asexternal shoulder38. Bearing62 (shown inFIG. 4) is press fit concentrically into sleeve bore56 so that it sits flush withupper surface60.Internal shoulder58 also has a lowerweight bearing surface64 which seats on theupper surface68 oflower bearing assembly66, shown inFIGS. 6-8.
Lower bearing assembly66 comprises alower gear insert70,ball bearings84,gear74 and spring pins76 and76′. As will become clear, thegear74 may be of any suitable gear design for transferring an input rotation rate to a mating or contacting gear, such as thegears110,110′ of themid-shaft gear assembly108, with a size and tooth number selected to provide a desired gear train or speed ratio when combined with contacting gears. For example, thegear74 may be configured as a straight or spiral bevel gear, a helical gear, a worm gear, a hypoid gear, and the like out of any suitable material. In a preferred embodiment, thegear74 is a spiral gear to provide a smooth tooth action at the operational speeds of thecentrifugal processing system10. Theupper surface68 oflower gear insert70 comprises an axially positionedsleeve72, which receives and holdsgear74.gear74 is preferably retained withinsleeve72 by the use of at least one and preferably two spring pins76 and76′ which are positioned withinspring pinholes73 and73′ extending horizontally throughlower gear insert70 intosleeve72. Thus, whengear74 havingspring pin receptacles77 and77′ is inserted intosleeve72 the spring pins76 and76′ enter the correspondingreceptacles77 and77′ thus holding thegear74 in place. Of course, other assembly techniques may be used to position and retaingear74 within thelower gear assembly66 and such techniques are considered within the breadth of this disclosure. For example,gear74 may be held insleeve72 by a number of other methods, such as, but not limited to being press fit or frictionally fit, or alternativelygear74 andlower gear insert70 may be molded from a unitary body.
Thebase78 oflower gear insert70 has a slightly larger diameter thanupper body80 oflower gear insert70 as a result of a slight flare. This slight flare producesshoulder82 upon whichball bearing84 is seated. Once assembledlower bearing assembly66 is received by sleeve bore56 extending throughneck portion36 oflower case shell32. A retainingring86 is then inserted into the annular space produced by the difference of the outer diameter of thelower bearing assembly66 and the inner diameter of sleeve bore56 aboveball bearings84. A second retaining ring87 (shown inFIG. 2) is also inserted into the annular space produced by the difference between the outer diameter of thelower bearing assembly66 and the inner diameter of sleeve bore56 belowball bearing84, thereby securinglower gear insert70 withinlower case shell32. Consequently,ball bearings62 and84 are secured by retainingrings86 and87, respectively resulting inlower case shell32 being journaled for rotation aboutlower bearing assembly66 but fixed against longitudinal and transverse movement thereon. Therefore, when assembledlower bearing assembly66 is mounted tostationary base12, by securingscrews14 into threadedholes79 located in thebase78.Lower case shell32 is thus able to freely rotate about stationarylower bearing assembly66 when thedrive belt26 is engaged.
Referring now toFIG. 5, extending from the opposite end ofneck portion36 onlower case shell32 are a number of protrusions orfingers88,90,92, and94. Positioned betweenprotrusions88 and90, and betweenprotrusions92 and94 are recessedslots96 and98, respectively, for receiving tube guide102 (FIG. 9). The function oftube guide102 will be discussed in further detail below, but in short it guidesumbilical cable228 connected tocentrifuge bag226 through themid-shaft gear assembly108 and out of thecentrifuge20.
Positioned betweenprotrusions90 and92, and betweenprotrusions88 and94 are recessedslots104 and106, respectively, for receivinggears110 and110′ of mid-shaft gear assembly108 (FIG. 2). Thegears110 and110′ are preferably configured to provide mating contact with thegear74 and to produce a desired, overall gear train ratio within thecentrifuge20. In this regard, thegears110 and110′ are preferably selected to have a similar configuration (e.g., size, tooth number, and the like) as thegear74, such as a spiral gear design. As illustrated inFIGS. 2 and 14mid-shaft gear assembly108 comprises a pair ofgears110 and110 engaged withgears74 and131. While the construction of gears and gear combinations is well known to one skilled in the mechanical arts, a brief description is disclosed briefly herein.
FIG. 10 illustrates an exploded view depicting the assembly ofgear110, andFIG. 11 is a perspective view of thegear110 ofFIG. 10 as it appears assembled.Gear110′ is constructed in the same manner.Gear111 is locked ontomid-gear shaft112 usingkey stock114 andexternal retaining ring116.Ball bearing118 is then attached tomid gear shaft112 using aflat washer120 andcap screw122. Recessedslots104 and106 oflower case shell32 then receiveball bearing118 and118′ (not shown). In an alternateembodiment ball bearing118 can be replaced by bushings (not shown). When assembled, gears110 and110′ make contact with the lower gear74 (seeFIGS. 2 and 14) to provide contact surfaces for transferring a force from thestationary gear74 to thegears110 and110′ to cause thegears110 and110′ to rotate at a predetermined rate that creates a desired output rotation rate for the drivenrotor assembly200. Therotor assembly200 is driven by thedrive shaft assembly28 which is rotated by thedrive motor24 at an input rotation rate or speed, and in a preferred embodiment, thedrive shaft assembly28 through the use of thegears110 and110′ is configured to rotate therotor assembly200 at an output rotation rate that is twice the input rotation rate (i.e., the ratio of the output rotation rate to the input rotation rate is 2:1). This ratio is achieved in the illustrated embodiment by locking thegears110 and110′ located within thedrive shaft assembly28 to rotate about the centrifuge center axis, A, with thelower case shell32 which is rotated by thedrive motor24. Thegears110 and110′ also contact thestationary gear74 which forces thegears110,110′ to rotate about their rotation axes which are traverse to the centrifuge center axis, A, and as illustrated, the rotation axes of thegears110,110′ coincide. By rotating with thelower case shell32 and rotating about the gear rotation axes, thegears110,110′ are able to provide the desired input to output rotation rate of 2:1 to therotor assembly200.
In this regard, gears110 and110′ andtube guide102 are locked into position by attachingtop bearing assembly124 tolower case assembly30. Top bearing assembly124 (as shown inFIG. 12) comprisestop case shell126,ball bearing128, and anupper bearing130.Top case shell126, as best seen inFIGS. 12 and 13, comprises anupper surface132, alower lip134 and a central oraxial bore136 there through.Upper surface132 slightly overhangsaxial bore136 resulting in ashoulder138 having a lower surface140 (shown inFIG. 13).Lower lip134 is a reverse image ofupper lip100 on lower case shell32 (shown inFIG. 5).
Upper bearing assembly130 (FIG. 12) comprises anupper surface133 and alower surface135 wherein theupper surface133 has a means for receiving arotor202. On the lower surface135 a concentrically positionedcolumn137 protrudes radially outward perpendicular tolower surface135.Upper bearing assembly130 further comprises an axially positioned bore139 that traversescolumn137 andupper surface133 and receivesupper gear insert131.Upper gear insert131 also contains an axial bore142 and thus when positioned concentrically withincolumn137axial bores139 and142 allow forumbilical cable228 to travel throughupper bearing assembly130 oftop case shell126 down to cable guide102 (shown inFIG. 14). As discussed previously with respect tolower bearing assembly66,upper gear insert131 may be any suitable gear design for receiving an input rotation rate from a mating or contacting gear, such as thegears110,110′ of themid-shaft gear assembly108, with a size and tooth number selected to provide a desired gear train or speed ratio when combined with contacting gears. For example,gear insert131 may be configured as a straight or spiral bevel gear, a helical gear, a worm gear, a hypoid gear, and the like. In a preferred embodiment,gear131 is a spiral gear to provide a smooth tooth action at the operational speeds of thecentrifugal processing system10.Gear insert131 is preferably retained withincolumn137 by use of at least one and preferably two spring pins (not shown); however, other assembly techniques may be used to position and retain thegear insert131 within thecolumn137 and such techniques are considered within the breadth of this disclosure. For example,gear insert131 may be held incolumn137 by a number of other methods, such as, but not limited to being press fit or frictionally fit or alternativelygear insert131 and the upper bearing assembly may be molded from a unitary body.
Upper bearing assembly130 is then inserted intoaxial bore136 oftop case shell126 so that thelower surface135 sits flush withupper surface132 oftop case shell126.Ball bearing128 is then inserted into the annular space created between the outer diameter ofcolumn137 and theinner side wall141 oftop case shell126 thereby securingupper bearing assembly130 into place.
Referring now toFIG. 13,lower lip134 is contoured to mate withprotrusions88,90,92 and94 extending fromlower case shell32. Specifically, the outer diameter oflower lip134 matches the outer diameter of the upper end ofmain body40 oflower case shell32 and recesses144 and148 receive and retainprotrusions88 and92 respectively, whilerecesses146 and150 receive and retainprotrusions94 and88, respectively. Holes are placed through each recess and each protrusion so that when assembled, fasteners152 (shown inFIG. 12) can be inserted through the holes thereby fastening thetop bearing assembly124 to thelower case assembly30.
Positioned betweenrecesses144 and146 and betweenrecesses148 and150 are recessedslots104′ and106′, respectively, for receivinggears110 and110′ of mid-shaft gear assembly108 (FIGS. 2 and 14). Thegears110 and110′ are preferably configured to provide mating contact with thegear insert131 and to produce a desired, overall gear train ratio within thecentrifuge20. In this regard, thegears110 and110′ are preferably selected to have a similar configuration (e.g., size, tooth number, and the like) as thegear131, such as a spiral gear design. Furthermore recessedslots96′ and98′ exist betweenrecesses144 and150 and betweenrecesses146 and148, respectively. When gears110 and110′ are assembled as shown inFIG. 14, recessedslots96 and96′ from thelower case shell32 andtop case shell126, respectively,form port154, and recessedslots98 and98′form port156 thereby allowing theumbilical cable228 to exitcentrifuge20 through eitherport154 or156. Described above is one method of assembling thecentrifugal processing system10 of the present invention; however, those skilled in the art will appreciate that thelower case assembly30 and upper bearing assembly can be joined in number of ways that allow the four gears to be properly aligned with respect to one another.
In the above manner, thecentrifugal processing system10 provides a compact, portable device useful for separating blood and other fluids in an effective manner without binding or kinking fluid feed lines, cables, and the like entering and exiting thecentrifuge20. The compactness of thecentrifugal processing system10 is furthered by the use of the entirely contained and interior gear train described above that comprises, at least in part,gear74, gears110 and110′, andgear insert131 of theupper bearing130. Thegear insert131 of theupper bearing130 is preferably selected to provide a contact surface(s) with thegears110 and110′ that transfers the rotation rate of thegears110 and110′ and consequently fromgear74 and to thegear insert131 of theupper bearing130. In one preferred embodiment, thegear insert131 of theupper bearing130 is a spiral gear rigidly mounted within theupper bearing130 to rotate therotor assembly200 and having a design similar to that of thespiral gear74, i.e., same or similar face advance, circular pitch, spiral angle, and the like. During operation, thegear74 remains stationary as thelower case shell32 is rotated about the centrifuge axis, A, at an input rotation rate, such as a rotation rate chosen from the range of 0 rpm to 5000 rpm. Thegears110,110′ are rotated both about the centrifuge axis, A, with theshell32 and by contact with thestationary gear74. The spiral gears110,110′ contact thegear insert131 of theupper bearing130 causing thegear insert131 and connectedupper bearing130 to rotate at an output rotation rate that differs, i.e., is higher, than the input rotation rate.
Although a number of gear ratios or train ratios (i.e., input rotation rate/output rotation rate) may be utilized to practice the invention, one embodiment of the invention provides for a gear train ratio of 1:2, where the combination and configuration of thegear74, gears110,110′, andgear131 of theupper bearing130 are selected to achieve this gear train ratio. Uniquely, the rotation of thegears110,110′ positively affects the achieved gear train ratio to allow, in one embodiment, the use of four similarly designed gears which lowers manufacturing costs while achieving the increase from input to output rotation speeds. Similarly, as will be understood by those skilled in the mechanical arts, numerous combinations of gears in differing number, size, and configuration that provides this ratio (or other selected ratios) may be utilized to practice the invention and such combinations are considered part of this disclosure. For example, although twogears110,110′ are shown in themid-shaft gear assembly108 to distribute transmission forces and provide balance within the operating centrifuge, more (or less) gears may be used to transmit the rotation ofgear74 to the gear of theupper bearing130. Also, just as the number, size, and configuration of the internal gears may be varied from the exemplary illustration ofFIGS. 1-14, the material used to fabricate thegear74, thegears110,110′, and thegear insert131 may be any suitable gear material known in the art.
Another feature of the illustratedcentrifugal processing system10 that advantageously contributes to compactness is the side-mounteddrive motor24. As illustrated inFIGS. 1 and 2, thedrive motor24 is mounted on thestationary base12 of theenclosure11 adjacent thecentrifuge20. Thedrive motor24 may be selected from a number of motors, such as a standard electric motor, useful for developing a desired rotation rate in thecentrifuge20 of thecentrifugal processing system10. Thedrive motor24 may be manually operated or, as in a preferred embodiment, a motor controller may be provided that can be automatically operated by a controller of thecentrifugal processing system10 to govern operation of the drive motor24 (as will be discussed in detail with reference to the automated embodiment of the invention). As illustrated inFIG. 1, adrive belt26 may be used to rotate the drive shaft assembly28 (and, therefore, the rotor assembly200). In this embodiment, thedrive belt26 preferably has internal teeth (although teeth are not required to utilize a drive belt) selected to mate with the external teeth of thetiming belt ring46 of thelower case assembly30 portion of thedrive shaft assembly28. The invention is not limited to the use of adrive belt26, which may be replaced with a drive chain, an external gear driven by themotor24, and any other suitable drive mechanisms. When operated at a particular rotation rate, thedrive motor24 rotates thedrive shaft assembly28 at nearly the same rotation rate (i.e., the input rotation rate). A singlespeed drive motor24 may be utilized or in some embodiments, a multi and/orvariable speed motor24 may be provided to provide a range of input rotation rates that may be selected by the operator or by a controller to obtain a desired output rotation rate (i.e., a rotation rate for therotor assembly200 and includedcentrifuge bag226.
The present invention generally includes an apparatus and methods for the separation of a predetermined fraction(s) from a fluid medium utilizing the principles of centrifugation. Although the principles of the present invention may be utilized in a plurality of applications, one embodiment of this invention comprises isolating predetermined fraction(s) (e.g., platelet rich plasma or platelet poor plasma) from anticoagulated whole blood. The platelet rich plasma may be used, for example, in the preparation of platelet concentrate or gel, and more particularly may be used to prepare autologous platelet gel during surgery using blood drawn from the patient before or during surgery.
Thecentrifuge20 has been discussed above and demonstrates the compact and portable aspects of the present invention. To complete the device of the present invention a fluid collection device, also referred to as a bowl orrotor202 is attached to theupper surface133 of theupper bearing assembly130 as shown inFIGS. 1 and 2.Rotor202 is preferably mounted permanently toupper bearing assembly130, however,rotor202 may also be capable of being removed.Rotor202 comprises a rotor base204 (shown inFIG. 15) having a lowerannular groove212, and arotor cover206 having an upperannular groove214. As shown inFIGS. 17 and 18 the annularinterior chamber216 ofrotor202 is defined by upper and lowerannular grooves212 and214. The lower annular212 receives acentrifuge bag226 for containing the fluid medium to be centrifuged.Centrifuge bag226 is connected to supply and receivingcontainers398,400, respectively, viaumbilical cable228 which is preferably, but not limited to a dual lumen. There may be instances where a certain technique requires multiple outlet or inlet ports and consequentlyumbilical cable228 of the present invention may comprise multiple lumens.Umbilical cable228 according to the preferred embodiment comprisesinlet lumen230 andoutlet lumen232 such that a fluid medium may be provided to and removed from thecentrifuge bag226 during rotation of thecentrifuge rotor202.
One embodiment ofcentrifuge rotor202 is more particularly illustrated inFIGS. 15,16,17 and18.FIG. 15 is a perspective view ofrotor base204, andFIG. 16, is a perspective view ofrotor cover206.FIG. 17 is a cross-sectional side view ofrotor202 taken alongview lines17 inFIG. 1, andFIG. 18 is a cross-sectional side view ofrotor202 taken alongview lines18 inFIG. 1. As illustrated inFIG. 15,rotor base204 comprises raisedannular rim208 and raisedcolumn218 that is axially disposed inbase204. Raisedcolumn218 further has agroove222 extending across the diameter ofcolumn218.Annular groove212 is defined by raisedannular rim208 and raisedcolumn218. The height ofrim208 is equal to the height ofcolumn218.Rotor cover206 shown inFIG. 16 comprises raisedannular rim210 and raisedcolumn220 which is axially disposed inrotor cover206. Raisedcolumn220 further has agroove224 extending across the diameter ofcolumn220.Annular groove214 is defined byrim210 andcolumn220. The height ofrim210 is equal to the height ofcolumn220.
Generally, whencentrifuge rotor202 is to be assembled for use, a flexible centrifuge bag such as a doughnut-shaped centrifuge bag226 (FIGS. 19 and 20) having acenter core242 is placed inrotor base204 such thatcenter column218 extends through thecore242 ofcentrifuge bag226 and thecentrifuge bag226 lies inannular groove212.Rotor cover206 is superimposed onrotor base204 such thatgrooves222 and224 are aligned, as illustrated inFIGS. 17 and 18. Whenrotor cover204 is secured torotor base206 by appropriate screws, fasteners, or the like (not shown), rims208 and210 are in complete contact with each other such thatannular groove212 andannular groove214 define rotorinterior chamber216. In one embodiment,columns218 and220 are in complete contact with each other. Alternatively, theinner perimeter240 ofcentrifuge bag226 is secured betweencolumns218 and220 such thatcolumns218 and220 do not completely physically contact each other.
With the above description of one embodiment of the centrifuge in mind, another preferred embodiment of a centrifuge for use in thecentrifugal processing system10 will be described. Referring toFIGS. 19-22, a preferred embodiment of acentrifuge640 is illustrated that utilizes a uniquely arranged internal pulley system to obtain a desired input to output drive ratio (such as 2:1, as discussed above) rather than an internal gear assembly. Thecentrifuge640 utilizes the side-mounted motor24 (shown inFIG. 1) throughdrive belt26 to obtain the desired rotation rate at the rotor portion of the centrifuge.
Referring first toFIG. 19, thecentrifuge640 includes a rotor base644 (or top plate) with a recessedsurface648 for receiving and supporting a centrifuge bag during the operation of thecentrifuge640. Therotor base644 is rigidly mounted with fasteners (e.g., pins, screws, and the like) to a separately rotatable portion (i.e., atop pulley698 discussed with reference toFIGS. 20 and 21) of alower case shell660. Acable port656 is provided centrally in therotor base644 to provide a path for a centrifuge tube or umbilical cable that is to be fluidically connected to a centrifuge bag positioned on the recessedsurface648 of therotor base644. It is important during operation of thecentrifuge640 to minimize and control contact and binding of the umbilical cable and moving paths (such as drive belts and pulleys). In this regard, thelower case shell660 includes aside cable port662 for the umbilical cable to enter thecentrifuge640, which, significantly, theside cable port662 is located betweenidler pulleys666,668 to provide a spacing between any inserted tube or cable and the moving drive components of thecentrifuge640.
Idler shaft or pins664 are mounted and supported within thelower case shell660 to allow thepins664 to physically support thepulleys666,668. The idler pulleys666,668 are mounted on thepins664 by bearings to freely rotate about the central axis of thepins664 during operation of thecentrifuge640. The idler pulleys666,668 are included to facilitate translation of the drive or motive force provided or imparted by thedrive belt26 to thelower case shell660 to therotor base644, as will be discussed in more detail with reference toFIGS. 20 and 21, and to physically support theinternal drive belt670 within thecentrifuge640. Thedrive belt26 is driven by the side-mounted motor24 (shown inFIG. 1) and contacts thelower case shell660 to force thelower case shell660 to rotate about its central axis. Thelower case shell660 is in turn mounted on the base674 in a manner that allows thelower case shell660 to freely rotate on the base674 as thedrive belt26 is driven by the side-mountedmotor26. Thebase674 is mounted to a stationary base12 (shown inFIG. 1) such that thebase674 is substantially rigid and does not rotate with thelower case shell660.
Referring now toFIGS. 20-22, thecentrifuge640 is shown with a cutaway view to more readily facilitate the discussion of the use of the internal pulley assembly to obtain a desired output to input ratio, such as two to one. As shown, the base674′ includesvibration isolators676 fabricated of a vibration absorbing material such as rubber, plastic, and the like through which thebase674 is mounted relatively rigidly to the stationary base12 (ofFIG. 1). Thedrive belt26 from the side-mounted motor24 (ofFIG. 1) contacts (frictionally or with the use of teeth and the like as previously discussed) adrive pulley680, which is rigidly mounted to thelower case shell660. As thedrive belt26 is driven by themotor24, thelower case shell660 throughdrive pulley680 rotates about its center axis (which corresponds to the center axis of the centrifuge640). This rotation rate of thelower case shell660 can be thought of as the input rotation rate or speed.
To obtain a desired, higher rotation rate at therotor base644, thelower case shell660 is mounted on, the base to freely rotate about the centrifuge center axis withbearings690 that mate with thebase674. Thebearings690 are held in place between thebottom pulley692 and thebase674, and thebottom pulley692 is rigidly attached (with bolts or the like) to the base674 to remain stationary while thelower case shell660 rotates. The illustratedbearings690 are two-piece bearings which allow thelower case shell660 to rotate on thebase674. Aninternal drive belt670 is provided and inserted through thelower case shell660 to contact the outer surfaces of thebottom pulley692. Thebelt670 preferably is installed with an adequate tension to tightly mate with thebottom pulley692 such that frictional forces cause thebelt670 to rotate around thestationary bottom pulley692. This frictional mating can be enhanced using standard rubber belts or belts with teeth (and of course, other drive devices such as chains and the like may be substituted for the belt670).
Theinternal drive belt670 passes temporarily outside thecentrifuge640 to contact the outer surfaces of theidler pulleys666 and668. Thesepulleys666,668 do not impart further motion to thebelt670 but rotate freely on pins664. The idler pulleys666,668 are included to allow the rotation about the centrifuge center axis bylower case shell660 to be translated to another pulley (i.e., top pulley698) that rotates about the same axis. To this end, the idler pulleys666,668 provide non-rigid (or rotatable) support that assists in allowing thebelt670 to be twisted without binding and then fed back into an upper portion of the lower case assembly660 (as shown clearly inFIGS. 20 and 21). As theinternal drive belt670 is fed into thelower case assembly660, thebelt670 contacts the outer surfaces of atop pulley698.
During operation of thecentrifuge640, the movement of theinternal drive belt670 causes thetop pulley698 to rotate about the centrifuge center axis. The idler pulleys666 and668 by the nature of their placement and orientation within thecentrifuge640 relative to thepulleys692 and698 cause therotor base644 to rotate in the same direction as thelower case shell660. Significantly, thetop pulley698 rotated about the centrifuge center axis at twice the input rotation rate because it is mounted to thelower case shell660 via bearings694 (preferably, a two piece bearing similar tobearings690 but other bearing configurations can be used) which are mounted to thecenter shaft686 of thelower case shell660 to frictionally contact an inner surface of thetop pulley698. Since theinternal drive belt670 is rotating about thebottom pulley692 and the idler pulleys666,668 are rotating about the centrifuge central axis bydrive belt26, thetop pulley698 is turned about the centrifuge central axis in the same direction as thelower case shell660 but at twice the rate.
In other words, the drive force of thedrive belt26 and theinternal drive belt670 are combined by the components of thecentrifuge640 to create the output rotation rate. While a number of output to input drive ratios may be utilized, as discussed previously, a 2:1 ratio is generally preferable, and thecentrifuge640 is preferably configured such that the second, faster rotation rate of thetop pulley698 is substantially twice that of thelower case shell660. The use of aninternal drive belt670 in combination with two pulleys rotating about the same axis and the structural support for the pulleys within a rotating housing results in a centrifuge that is very compact and that operates effectively at a 2:1 drive ratio with relatively low noise levels (which is desirable in many medical settings).
The 2:1 drive ratio obtained in thetop pulley698 is in turn passed on to therotor base644 by rigidly attaching therotor base644 to thetop pulley698 withfasteners652. Hence, a centrifuge bag placed on the recessedsurface648 of therotor base644 is rotated at a rate twice that of theumbilical cable228 that is fed intolower case shell660, which effectively controls binding as discussed above. The bearing694 (one or more pieces) wrap around theentire center shaft686 of thelower case shell660. To provide a path for theumbilical cord228 to pass through thecentrifuge640 to the rotor base644 (which during operation will be enclosed with a rotor top or cover as shown inFIG. 1), therotor base644 includes thecable port656 and thecenter shaft686 is configured to be hollow to form a center cable guide. This allows anumbilical cable228 to be fed basically parallel to the centrifuge center axis to the centrifuge bag (not shown). Thelower case shell660 includes theside cable port662 to provide for initial access to thecentrifuge640 and also includes the side cable guide (or tunnel)684 to guide thecable228 through thelower case shell660 to the hollow portion of thecenter shaft686. Theside port662 and theside cable guide684 are positioned substantially centrally between the twoidler pulleys666,668 to position the cable228 a distance away from theinternal drive belt670 to minimize potential binding and wear.
Thecentrifuge640 illustrated inFIGS. 19-22 utilizes two-piece bearings for both the bottom andtop pulleys692 and698, respectively, and to provide a path for the umbilical cable228 a central “blind” pathway (viaside cable guide684, the hollow center of thecenter shaft686, andcable ports656,662) was provided in thecentrifuge640. While effective, this “blind” pathway can in practice present binding problems as the relativelystiff cable228 is fed or pushed through the pathway. To address this issue, analternate centrifuge embodiment700 is provided and illustrated inFIGS. 23 and 24. In this embodiment, the upper portions of thecentrifuge700 include a guide slot between theidler pulleys666,668 that enables anumbilical cable228 to be fed into thecentrifuge700 from the top with the no components to block the view of the operator inserting thecable228.
To allow a guide slot to be provided, the contiguousupper bearing694 in thecentrifuge640 are replaced with bearing members that have at least one gap or separation that is at least slightly larger than the outer diameter of thecable228. A number of bearing members may be utilized to provide this cable entry gap and are included in the breadth of this disclosure. As illustrated, thecentrifuge700 includes arotor base702 that is rigidly fastened withfasteners704 to the top pulley698 (not shown) to rotate with this pulley at the output rate (e.g., twice the input rate) and to receive and support a centrifuge bag on recessedsurface716. Therotor base702 further includes thecable port718 which is useful for aligning the center of the bag andcable228 with the center of thecentrifuge700.
To allow ready insertion of thecable228 in thecentrifuge700, therotor base702 further includes acable guide slot712 which as illustrated is a groove or opening in therotor base702 that allows thecable228 to be inserted downward through thecentrifuge700 toward theside cable guide724 of thelower case shell720. Thelower case shell720 also includes acable guide slot722 cut through to the top of theside cable guide724. Again, theguide slots712 and724 are both located in a portion of thecentrifuge700 that is between theidler pulleys666,668 to position an insertedcable228 from contacting and binding with theinternal drive belt670, which basically wraps around 180 degrees of the top pulley orlower case shell720.
As shown inFIG. 23, the bearingmembers706 are spaced apart and preferably, at least one of these spaces or gaps is large enough to pass through thecable228 to the center shaft of thelower case shell720. As illustrated, four cam followers are utilized for the bearingmembers706, although a different number may be employed. Thecam followers706 are connected to the top pulley to enable the top pulley to rotate and are connected, also, to the center shaft of thelower case shell720 to rotate with thelower case shell720. Thecam followers706 ride in abearing groove710 cut in thelower case shell720. To provide an unobstructed path for thecable228, thecable guide slots712 and722 are positioned between the twocam followers706 adjacent the idler pulleys666,668, and preferably theguide slots712,722 are positioned substantially centrally between thepulleys666,668. Theguide slots712,722 are positioned between thesecam followers706 to position thecable228 on the opposite side of thecentrifuge700 as the contact surfaces between theinternal drive belt670 and the top pulley698 (shown inFIG. 20-22). In this manner, the use of separated bearingmembers706 in combination with a pair ofcable guide slots712,722 allows an operator to readily install theumbilical cable228 without having to blindly go through the inside of the drive system and minimizes binding or other insertion difficulties.
One embodiment of disposable,flexible centrifuge bag226 is more particularly illustrated inFIGS. 25 and 26. The bag is an integral two stage self-balancing disposable design. Thedisposable centrifuge bag226 has a substantially flat, toroidal- or doughnut-shaped configuration having outer andinner perimeters238 and240, respectively, and comprises radially extending upper andlower sheets234,236 formed from a substantially flexible material. The upper andlower sheets234,236 are superimposed and completely sealed together atouter perimeter238 by a heat weld, rf (radio frequency) weld or other comparable method of adhering two surfaces.Inner perimeter240 definescore242 ofbag226. In one embodiment of the invention,centrifuge bag226 further comprises aninlet tube248 sandwiched between upper andlower sheets234,236 and extending from the center ofcore242 defined byinner perimeter240 to theouter perimeter238 and anoutlet tube250 sandwiched between upper andlower sheets234,236 and extending from the center of the core242 to theouter perimeter238. When upper andlower sheets234,236 are sealed together atinner perimeter240, inlet andoutlet tubes248,250 are thereby sealed therebetween. Inlet andoutlet tubes248,250 are each in fluid communication with the interior ofcentrifuge bag226 and the environment outsidecentrifuge bag226. The length ofoutlet tube250 is shorter than the length ofinlet tube248.
In one embodiment of this invention,outlet tube250 is a straight tube as shown inFIG. 31. Alternatively,outlet tube250 includes abent fitting252 fluidly connected to the distal end of outlet tube250 (FIGS. 25 and 26). Thebent fitting252 may be of any number of configurations, although preferably bent fitting252 is shaped in the form of a “T”, “curved T”, a “J”, or an “L”, as illustrated inFIGS. 27,28,29 and30, respectively. Alternatively,outlet tube250 andbent fitting252 may be one contiguous molded unit rather than two connected pieces. Preferably,bent fitting252 is in the shape of a “T” or a “curved T” as illustrated inFIGS. 27 and 28, respectively. The “T” or “curved T” design ofbent fitting252 ensures that the desired blood component (fraction) will be removed from the sides of thebent fitting252, rather than from a, fraction located above or below the bent fitting, as discussed below in detail.
When thecentrifuge bag226 is positioned in theannular groove212 of thecentrifuge rotor202 as described above, it is critical that inlet andoutlet tubes248,250 are seated ingroove222. Further, whenrotor cover206 is positioned over and removably secured to thecentrifuge base204, it is important that inlet andoutlet tubes248,250 are also seated ingroove224. Seating inlet andoutlet tubes248,250 ingrooves222,224 ensures thatcentrifuge rotor202 is held in a fixed position betweenrotor base204 androtor cover206 such that thecentrifuge bag226 andcentrifuge rotor202 rotate together. That is, the fixed position ofcentrifuge bag226 ensures thatcentrifuge bag226 will not rotate independently ofcentrifuge bag226 during centrifugation.
Inlet andoutlet tubes248,250 are fluidly connected at their proximal ends toumbilical cable228, which in this particular embodiment is a dual lumen tubing connectingcentrifuge bag226 to source and receivingcontainers398,400, respectively, for the introduction and removal of components from thecentrifuge bag226 during centrifugation (seeFIG. 17).Dual lumen tubing228 comprisesinlet lumen230, which connectsinlet tube248 ofcentrifuge bag226 withsource container398, andoutlet lumen232, which connectsoutlet tube250centrifuge bag226 with receivingcontainer400. In one embodiment, the inlet andoutlet tubes248,250 are adapted at their proximal ends for inserting into the inlet andoutlet lumens230 and232, respectively. Alternatively, connecting means254 are inserted into the proximal ends of inlet andoutlet tubes248,250 for connecting the tubes to the inlet andoutlet lumens230,232 as illustrated inFIG. 26.
In operation, one end ofumbilical cable228 must be secured torotor assembly200 to prevent itself from becoming twisted during rotation ofrotor assembly200 by the coaxial half-speed rotation ofdrive shaft assembly28, which imparts a like rotation with respect to therotor202 axis and consequently to theumbilical cable228 that is directed throughcable guide102. That is, ifrotor assembly200 is considered as having completed a first rotation of 360° and driveshaft assembly28 as having completed a 180° half-rotation in the same direction, theumbilical cable228 will be subjected to a 180° twist in one direction about its axis. Continued rotation ofrotor assembly200 in the same direction for an additional 360° and driveshaft assembly28 for an additional 180° in the same direction will result inumbilical cable228 being twisted 180° in the opposite direction, returningumbilical cable228 to its original untwisted condition. Thus,umbilical cable228 is subjected to a continuous flexture or bending during operation of thecentrifugal processing system10 of the present invention but is never completely rotated or twisted about its own axis.
An alternative embodiment of a disposable centrifuge bag of this invention, shown inFIG. 35 comprises two or more inlet tubes and/or two or more outlet tubes, wherein the tubes are fluidly connected to a multiple lumen tubing.
Thedisposable centrifuge bag226 is formed from a transparent, substantially flexible material, including but not limited to, polyvinyl chloride, polyethylene, polyurethane, ethylene vinyl acetate and combinations of the above or other flexible materials. Based upon the flexibility of thecentrifuge bag226, the profile of theflexible centrifuge bag226, shown inFIGS. 25 and 26, is determined at least in part by the amount of fluid contained therein. The profile ofcentrifuge bag226 is further defined by the interior configuration of the centrifuge rotor, as discussed below in detail. The ability to manipulate the profile ofcentrifuge bag226 based on the interior configuration of the centrifuge rotor is utilized at least in part to maximize the volume of fluid medium that can be contained incentrifuge bag226 during centrifugation, as will be discussed below.
The fluid or medium to be centrifuged may be contained within source container300. For example, when thecentrifuge20 of this invention is used to prepare an autologous platelet gel, the fluid (i.e., whole blood), may be withdrawn from the patient during or prior to surgery intosource container398 containing an anticoagulant. The anticoagulated whole blood is introduced tocentrifuge bag226 throughinlet tube248 viainlet lumen230 after thecentrifuge bag226 has been positioned in thecentrifuge rotor202 and rotation thereof is initiated. As discussed above, securingcentrifuge bag226 incentrifuge base204 ingrooves222,224 holds thecentrifuge bag226 in a fixed position therebetween, such that thecentrifuge bag226 cannot move independently of thecentrifuge rotor202, and therefore thecentrifuge bag226 androtor assembly200 rotate concurrently at the same rate of rotation. Rotation of thecentrifuge rotor202 directs the heavier density constituents of the anticoagulated whole blood within thecentrifuge bag226 toward theouter perimeter238 of thebag226, while the lighter density constituents remain closer to an inner region, as illustrated inFIG. 32. More specifically, as illustrated inFIG. 32, when the fluid medium being separated is whole blood, the whole blood is separated withincentrifuge bag226 into a red blood cell fraction (256), a white blood cell fraction (258), a platelet rich plasma fraction (260), and a platelet poor plasma fraction (262). As will be appreciated by those of skill in the art, whole blood fractions, red blood cells and plasma are differently colored, and consequently the separation of the fractions can be easily detected by the operator. At an appropriate time during centrifuging, suction or other drawing means may be applied to the interior ofcentrifuge bag226 viaoutlet lumen232 to remove the desired fraction from thecentrifuge bag226. In a further embodiment,centrifuge cover206 may further contain concentric index lines to assist the operator in viewing the positions ofoutlet tube250 to the RBC plasma interface. Based on the speeds and times the location of the WBC and platelets can be varied with respect to the interface between the red blood cells and plasma. For example, if the rpm is held low (approximately 1,000-1,700, preferably 1,500) the plasma and platelets will separate from the RBC layer, as the rpm's are increased (1,400-1,700) the platelets will separate out of the plasma and reside at the plasma to RBC interface in greater concentrations. With increased speeds, the WBC's reside deeper into the RBC pack.
With further regard tobent fittings252, in one embodiment a bent fitting is fluidly connected to the distal end ofoutlet tube250. Whilebent fitting252 is shown inFIG. 32 as having a “T” shape (FIG. 27), this is for illustrative purposes only. Thus, it will be appreciated thatbent fitting252 as shown inFIG. 32 could have a number of other configurations, such as those shown inFIGS. 25-31. The design ofbent fitting252 ensures that the desired component is withdrawn (e.g., the platelet rich plasma fraction260) with less risk of contamination from withdrawing a portion of theadjacent fraction258. Thus, in one embodiment, the desired fraction is withdrawn when its position overlaps with the position ofbent fitting252. Alternatively, theinlet tube248 may be first used to draw off the redblood cell fraction256, and when it is desirable to remove the predetermined fraction from thecentrifuge bag226, the predetermined fraction is drawn throughbent fitting252 andoutlet tube250 and directed to receivingcontainer400 viaoutlet lumen232.
With continued reference toFIG. 32, as the separation of the fluid medium is initiated by centrifugation, substantially annular regions having constituents of a particular density or range of densities begin to form. For purposes of illustration, the separation of whole blood will be discussed, and as shown inFIG. 32 four regions are represented, each of which contains a particular type of constituent of a given density or range of densities. Moreover, it should be appreciated that there may be a given distribution of densities across each of the regions such that the regions may not be sharply defined. Consequently, in practice the regions may be wider (e.g., a larger radial extent) and encompass a range of densities of constituents.
In the example ofFIG. 32, thefirst region256 is the outermost of the four regions and contains red blood cells. Thesecond region258 contains white blood cells, which have a lower density than that of the red blood cells. Thethird region260 contains the platelet rich plasma fraction, and theinnermost region262 contains the least dense platelet poor plasma fraction. In one embodiment, it may be desired to harvest the platelet rich plasma fraction inregion260. In order to remove the platelet rich plasma fraction from thecentrifuge bag226, vacuum or suction is provided viaoutlet lumen232 to thecentrifuge bag226 to remove a desired portion ofregion260. A portion of thefraction260 that is in the area of thebent fitting252 is drawn throughbent fitting252 and into an appropriate one of the collection containers400 (FIG. 17).
More specifically,FIGS. 33-39 illustrate one method of this invention for the separation of whole blood components, which is a dynamic process.FIG. 33 shows one portion of thecentrifuge bag226, illustrating the separation of the whole blood components after infusion of an aliquot of whole blood intocentrifuge bag226 and centrifugation for approximately 60 seconds to 10 minutes at a rate of rotation between 0 and 5,000 rpms. It will be understood by those of skill in the art that faster speeds of rotation will separate the blood in a shorter prior of time.
FIG. 33 shows the four separated whole blood fractions, with the denser fractions closer toouter perimeter238, and the less dense fractions closer to inner-perimeter240. While it is well-known that hematocrits (i.e., the volume of blood, expressed as a percentage, that consists of red blood cells) will vary among individuals, ranging from approximately 29%-68%, such variations are easily adjusted for as a result of the novel design ofcentrifuge bag226 and consequently will not affect the isolation of any of the desired fractions as discussed below in detail. Thus, for illustrative purposes, it will be assumed that centrifugation of an initial infusion of an aliquot of anticoagulated whole blood will give the profile shown inFIG. 33. In one embodiment, it is desired to harvest the plateletrich plasma fraction260. This may be achieved by performing a batch separation process or a continuous separation process as described below.
In one embodiment of a batch separation process of this invention for harvesting the plateletrich plasma fraction260,centrifuge bag226 has a design as shown inFIG. 32 whereinbent fitting252 positioned approximately in the area where a plateletrich plasma fraction260 is typically found after centrifugation of an aliquot of whole blood. This approximation is simplified by the placement of concentric indicator lines205,207, and209, (not shown) in the upper surface ofrotor cover206, wherein the concentric lines205,207 and209 correspond approximately with the edges ofregions260,258, and256, respectively. Alternative, concentric lines similar to205,207 and209 may be directly imprinted onto the surface ofcentrifuge bag226.
After centrifugation of an aliquot of blood contained incentrifuge bag226, a substantial portion of the plateletrich plasma fraction260 is withdrawn fromcentrifuge bag226 throughbent fitting252 whilecentrifuge rotor202 is still spinning. As the volume of the plateletrich plasma fraction260 is reduced upon withdrawal, theinnermost fraction262 naturally moves in the direction of theouter perimeter238 due to centrifugal force, as shown inFIG. 34. The withdrawal of plateletrich plasma fraction260 is terminated at a point where the plateletpoor plasma fraction262 is close tobent fitting252 and before any significant portion of plateletpoor plasma fraction262 could be withdrawn throughbent fitting252, as shown inFIG. 34. This point can be determined either visually by the operator by volume, or by a sensor, as described below in detail. After withdrawal of the desired plateletrich plasma fraction260,inlet lumen230 is disconnected from the wholeblood source container398 and connected to a disposal container, after which the remaining fluid incentrifuge bag226 is evacuated throughinlet tube248 and directed to the disposal container. The inlet lumen is then reconnected to the whole blood source container, and the above-described batch process is repeated as many times as required until the necessary quantity of the desired fraction is isolated.
Alternatively, the above-described process can be performed as a continuous process wherein the step of disconnecting theinlet lumen230 from thewhole blood source398 can be avoided. The continuous process separation of whole blood may be achieve by using adisposable centrifuge bag226′ as illustrated inFIGS. 35-39 comprising aninlet tube248 and threeoutlet tubes245,247 and250, wherein the tubes are connected to an umbilical cable comprising four lumens. More specifically, a disposable centrifuge bag for use in a continuous separation of whole blood comprisesinlet tube248 connected via an inlet lumen to a whole blood source container, afirst outlet tube250 connected to a first outlet lumen that is in turn connected to a platelet rich plasma receiving container, asecond outlet tube245 connected via a second outlet lumen to either a red blood cell receiving container or a waste container and athird outlet tube247 connected via a third outlet lumen to a platelet poor plasma receiving container. In the continuous separation process, after withdrawal of the portion of platelet rich plasma or other cellular components as described above with reference toFIGS. 33 and 34. Centrifuge bag has the capacity to receive an additional volume (aliquot) of whole blood. Consequently, as shown inFIG. 35 infusion of an aliquot of whole blood is reinitiated throughfirst inlet tube248 with continued centrifugation until the capacity of thecentrifuge bag226′ is reached. As a result of the additional volume of blood, the profile of the blood fractions incentrifuge bag226′ will approximately assume the profile shown inFIG. 35. As can be seen inFIG. 35, the additional volume of blood results in a shift of the location of the blood fractions, such that the plateletrich plasma fraction260 has shifted back into the area of thebent fitting252, and the plateletpoor plasma fraction262 has shifted back towards theinner perimeter240 and away from the vicinity of thebent fitting252. Additional plateletrich plasma260 can now be removed fromcentrifuge bag226′ throughoutlet tube250 as shown inFIG. 35.
As described above, removal of an additional volume of the plateletrich plasma fraction260 results in a shift in the location of the plateletpoor plasma fraction262 closer to theouter perimeter238 and consequently closer to the vicinity ofbent fitting252, as shown inFIG. 36, at which point removal of platelet rich plasma is again temporarily terminated.
Additional infusions of whole blood aliquots tocentrifuge bag262′ and removal of platelet rich plasma (by shifting the position of the plateletrich plasma fraction260 relative to the position of the bent fitting252) as described above may be repeated a number of times. Eventually, however, the continued infusion of whole blood followed by removal of only the platelet rich plasma fraction will necessarily result in a gradual increase in the volumes (and consequently the widths) of the remainingblood fractions256,258 and260 incentrifuge bag226′. In particular, the volume, and therefore the width, of the redblood cell fraction256 will increase to the extent that the other fractions are pushed closer to the inner perimeter240 (FIG. 37). As shown inFIG. 37, the increased volume of red blood cells now present incentrifuge bag226′ shifts the location of the fractions towards theinner perimeter240 such that the whiteblood cell fraction260 is now, in the vicinity of thebent fitting252 as opposed to the desired plateletrich plasma fraction262.
The novel design ofcentrifuge bag226′ advantageously provides means for shifting the fractions back to the desired locations when the situation shown inFIG. 37 arises. That is,second outlet tube245 serves as an inlet conduit for introduction of whole blood aliquots intocentrifuge bag226′, also serves the function of withdrawing fractions that are located close to theouter perimeter238. This is achieved in part by attaching the second outlet lumen to either a red blood cell receiving container or a waste container having a suction means (e.g., syringe, pump, etc.) As shown inFIG. 38,second outlet tube245, having its distal end close toouter perimeter238, can be operated to withdraw a substantial volume of the redblood cell fraction256, which in turn shifts the location of the remainingfractions258,260,262. The withdrawal of the redblood cell fraction256 may be monitored visually by the operator, or by other means such as a sensor. Alternatively, the positions of the fractions may be shifted by withdrawing the plateletpoor plasma fraction262 throughthird outlet tube247, which is connected via a third outlet lumen to a platelet poor plasma receiving container.
FIG. 37 shows that, after withdrawal of a portion of the redblood cell fraction256, thecentrifuge bag226′ again has the capacity to receive an additional volume of whole blood for centrifugation. An additional infusion of an aliquot of whole blood throughinlet tube248 into thecentrifuge bag226′ ofFIG. 37 and centrifugation will produce the profile illustrated inFIG. 39. The above-described steps may be repeated as needed until the desired amount of platelet rich plasma has been harvested. All of the above-described steps occur while thecentrifuge rotor202 is spinning.
The above-described continuous separation method was illustrated in terms of performing the whole blood infusion step and the platelet rich plasma harvesting step sequentially. An alternative embodiment involves performing the infusion and harvesting steps substantially simultaneously, that is, the platelet rich plasma fraction is withdrawn at approximately the same time as an additional aliquot of whole blood is being added to the bag. This alternate embodiment requires that the centrifuge rotor spin at a rate that results in almost immediate separation of the blood components upon infusion of an aliquot of whole blood.
As stated previously, all of the above-described steps may be monitored either visually by the operator by volume, or by a sensor. If the steps are to be visually monitored,centrifuge cover206 may further include one or more concentric indicator circles205,207,209 (shown inFIGS. 17 and 18) which may be spaced from the center ofcover206 at distances approximately equal to the outer edges ofregions260,258256, respectively, to aid the operator in visualizing the positions of these regions with respect to252.
FIGS. 33-39 illustrate one embodiment of how the design ofcentrifuge bags226 and226′ permit the general locations of the various blood fractions to be shifted to allow for continuous harvesting of a desired blood fraction without the risk of contaminating the harvested blood fraction, and further allow for continual on-line harvesting of a large volume (10 to 5 L's) of blood using a small, portable centrifuge device comprising a 10 cc to 200 cc capacitydisposable centrifuge bags226 and226′.
For example, the design ofcentrifuge bag226 havinginlet tube248 andoutlet tube250 means that the desired component or fraction will be withdrawn fromcentrifuge bag226 only throughoutlet tube250, while the addition of whole blood aliquots or the removal of other components (e.g., red blood cell fraction256) will proceed only through dualfunctional inlet tube248. In this respect, the harvested fraction (e.g., platelet rich plasma fraction260) is never withdrawn throughinlet tube248 which was previously exposed to other fluid media (e.g., whole blood or red blood cells). Thus, the design ofcentrifuge bag226 offers a significant advantage over conventional centrifuge containers comprising only one tube which serves to both introduce the fluid medium to the container and to withdraw the harvested fraction from the container.
Furthermore, because of its unique design the use ofcentrifuge bags226 and226′ are independent of composition of the whole blood to be centrifuged. For example, as stated above, hematocrits (i.e., the percent volume of blood occupied by red blood cells) vary from individual to individual, and consequently the profile illustrated inFIG. 32 will vary from individual to individual. That is, the width of redblood cell fraction256 may be wider or narrower, which in turn will result in the plateletrich plasma fraction260 being positioned further away in either direction frombent fitting252. However, as discussed above in detail with particular reference toFIGS. 33-34, the design ofcentrifuge bags226 and226′ allow the location of the desired fraction to be shifted until it is in the region ofbent fitting252. Such shifting can be brought about, for example usingcentrifuge bag226, by withdrawing the red blood cell fraction throughinlet tube248, or by adding whole blood aliquots throughinlet tube248.
An alternative embodiment of a disposable,flexible centrifuge bag270 is illustrated inFIG. 40. Thedisposable centrifuge bag270 has a substantially flat, toroidal- or doughnut-shaped configuration having outer andinner perimeters271 and272, respectively, and comprises radially extending upper and lower sheets273,274 formed from a substantially flexible material. The upper and lower sheets273,274 are superimposed and completely sealed together atouter perimeter271 by an rf weld, heat weld or other comparable method of adhering two surfaces.Inner perimeter272 definescore275 ofcentrifuge bag270. In one embodiment of the invention,centrifuge bag270 further comprisesinlet tube276 sandwiched between upper and lower sheets273,274 and radially extending from the center ofcore275 to theouter perimeter271, andoutlet tube278 sandwiched between upper and lower sheets273,274 and extending across the diameter ofcore275 and having first and second distal ends280,281. When upper and lower sheets273,274 are sealed together atinner perimeter272, inlet andoutlet tubes276,278 are thereby sealed therebetween. Inlet andoutlet tubes276,278 are each in fluid communication with the interior ofcentrifuge bag270 and the environment outsidecentrifuge bag270.Inlet tube276 andoutlet tube278 are fluidly connected to umbilical cable228 (not shown), which in this particular embodiment is a dual lumen tubing.Inlet tube276 is fluidly connected at its proximal end toumbilical cable228, preferably by an L-shaped connector (not shown), andoutlet tube278 is fluidly connected at its center toumbilical cable228 via a T-shaped connector (not shown).
Thedisposable centrifuge bag270 is formed from a transparent, substantially flexible material, including but not limited to, polyvinyl chloride, polyethylene, polyurethane, ethylene vinyl acetate and combinations of the above or other flexible materials.
Upper and lower sheets273,274 ofcentrifuge bag270 are further sealed at two portions between the outer perimeter and the inner perimeter. That is,centrifuge bag270 further comprises a first C-shapedseal282 located between the outer andinner perimeters271,272 and having an first concave indentation or well283 on the concave side of C-shapedseal282, and a second C-shapedseal284 located between the outer andinner perimeters271,272 and having an second concave indentation or well285 on the concave side of C-shapedseal284. First and second C-shapedseals282 and284 are formed by sealing portions of upper and lower sheets273,274 together by methods known in the art for sealing two surfaces, including but not limited to rf or heat welding.Ends288 and289 of first C-shapedseal282 are bent inward towards theinner core275, and likewise ends290 and291 of second C-shapedseal284 are bent inward towards theinner core275. First and second C-shapedseals282,284 have their concave sides facing each other such that the first andsecond indentations283,285 are diametrically opposed to each other. That is, whencentrifuge bag270 is viewed from the top as inFIG. 40, first and second C-shapedseals282,284 are mirror images of each other. First and second C-shapedseals282,284 together define anouter chamber292 between theouter perimeter271 and first and second C-shapedseals282,284, wherein theouter chamber292 has a toroidal configuration and serves as a first processing compartment. First and second C-shapedseals282,284 together further define aninner chamber293 between first and second C-shapedseals282,284 andinner perimeter272, wherein theinner chamber293 has a toroidal configuration and serves as a second processing compartment. The first and second C-shapedseals282,284 are positioned such that ends288 and290 are directly opposite and spaced apart from each other to define afirst channel286 therebetween, and such that ends289 and291 are directly opposite and spaced apart from each other to define asecond channel287 therebetween, wherein the first andsecond channels286,287 are diametrically opposed and provide fluid communication between thefirst processing compartment292 and thesecond processing compartment293.Inlet tube276 extends through eitherchannel286 orchannel287, and the first and second distal ends280,281 ofoutlet tube278 extend into first andsecond indentations283,285, respectively.
Centrifuge bag270 is removably secured betweenrotor base204 androtor cover206 ofrotor202 in a manner as described above so thatcentrifuge bag270 is held in a fixed position relative torotor base204 androtor cover206 during rotation of thecentrifuge rotor202. As will be appreciated by those of skill in the art, alternative embodiments of rotor base204 (FIG. 15) and rotor cover206 (FIG. 16) will be required to accommodate the design ofcentrifuge bag270. Thus, an alternate embodiment ofrotor base204 comprises raisedcolumn218 comprising first and second grooves which are perpendicular to each other and extend the diameter of the raisedbase column218, such that whenrotor202 is assembled,inlet tube276 andoutlet tube278 ofcentrifuge bag270 are seated in the first and second grooves, respectively, of raisedbase column218. Similarly, an alternate embodiment ofcover206 comprises raisedcolumn220 comprising first and second grooves which are perpendicular to each other and extend the diameter of the raisedcover column220, such that whenrotor202 is assembled,inlet tube276 andoutlet tube278 are further seated in the first and second grooves, respectively, of raisedcover column220.
As stated above, inlet andoutlet tubes276,278 are fluidly connected toumbilical cable228, which in this particular embodiment is a dual lumen tubing connectingcentrifuge bag270 to source and receivingcontainers398,400, respectively, for the introduction of the fluid to be centrifuged inbag270 and for the removal of one or more of the separated components from thecentrifuge bag270 during rotation of thecentrifuge20.Dual lumen tubing228 comprisesinlet lumen230, which connectsinlet tube276 withsource container398, andoutlet lumen232, which connectsoutlet tube278 with receivingcontainer400.
The fluid or medium to be centrifuged usingcentrifuge bag270 may be contained withinsource container398. For example, when thecentrifuge20 of this invention is used to prepare an autologous platelet gel, the fluid (i.e., whole blood), may be withdrawn from the patient during or prior to surgery intosource container398 containing an anticoagulant. The anticoagulated whole blood is introduced tocentrifuge bag270 throughinlet tube276 viainlet lumen230 after thecentrifuge bag270 has been positioned in thecentrifuge rotor202 and rotation thereof is initiated.
Centrifuge bag270 may be used for the separation and isolation of one or more components dissolved or suspended in a variety of fluid media, including, but not limited to, the separation of cellular components from biological fluids. For example,centrifuge bag270 is useful for the concentration and removal of platelets from whole blood. Therefore, the following description of the separation of platelets from whole blood usingcentrifuge bag270 is merely for purposes of illustration and is not meant to be limiting of the use ofbag270. The separation of a fluid medium such as whole blood incentrifuge bag270 may be considered to be a two-stage separation process. The first stage of the separation of platelets from whole blood involves separation of a platelet suspension from the red blood cells. The platelet suspension is typically plasma rich in platelets, and it is commonly referred to as platelet-rich plasma (PRP). However, as used herein; the term “platelet suspension” is not limited to PRP in the technical sense, but is intended to encompass any suspension in which platelets are present in concentrations greater than that in whole blood, and can include suspensions that carry other blood components in addition to platelets. The second stage of the separation comprises separating platelets from the platelet suspension to produce a platelet concentrate. As used herein, the term. “platelet concentrate” is intended to encompass a volume of platelets that results after a “platelet suspension” undergoes a subsequent separation step that reduces the fluid volume of the platelet suspension. The platelet concentrate may be a concentrate that is depleted of white blood cells and red blood cells.
With reference toFIG. 41, stage one of a whole blood separation process usingcentrifuge bag270 begins with the introduction of an aliquot of whole blood intocentrifuge bag270 viainlet tube276 during rotation of thecentrifuge20. As the aliquot of whole blood entersouter chamber292 ofcentrifuge bag270, it quickly separates radially under the influence of centrifugal force into various fractions withinouter chamber292 based on the densities of the components of the whole blood, including an outermost fraction containing the red blood cells which pack along theouter perimeter271 ofcentrifuge bag270, and an inner fraction comprising the platelet suspension. The platelet suspension after centrifugation of the first aliquot of whole blood is represented inFIG. 41 byring294. Continued infusion of whole blood into thefirst processing compartment292 adds an additional volume of red blood cells and consequently pushes the platelet suspension inward as represented byring295. Additional infusions of whole blood will continue to push the platelet suspension further inward, as represented byrings296 and297 until thefirst processing compartment292 is substantially filled with red blood cells (the remainder of the volume being plasma) such that the platelet suspension is pushed throughchannels286 and287 intosecond processing compartment293. As discussed above, theends288,289 and290,291 of C-shapedseals282,284, respectively, bend inward, which both helps to funnel the platelet suspension throughchannels286,287 and to minimize the amount of red blood cells that pass throughchannels286,287. The point at which the red blood cells are near the entrance ofchannels286,287 may be monitored either visually or by a sensor, as described below in detail. At this point the infusion of additional aliquots of whole blood is terminated, and the second stage of the two-stage separation process begins.
During stage two of the separation process, the platelet suspension which was pushed throughchannels286,287 into thesecond processing compartment293 flow under the influence of centrifugal force towards positions within thesecond processing compartment293 that have the greatest radial distances, that is, towardsconcave wells283,285, where the platelets, being the higher density component of the platelet suspension, begin to collect and pack. The platelets can then be withdrawn fromconcave wells283,285 throughoutlet tube278. In the above-described two-stage process for the separation of a platelet suspension from whole blood, the first and second C-shapedseals282,284 thus serve as physical barriers between the red blood cells and the platelets to facilitate the separation and collection of platelets from whole blood. First and secondconcave wells283,285 act as reservoirs for containing the platelets as they are separated from the platelet suspension in the second stage of the separation process.
After withdrawal of the platelets from thewells283 and285,inlet lumen230 is disconnected from the whole blood source container, after which the remaining components incentrifuge bag270 are evacuated throughinlet tube276 by applying suction toinlet lumen230 and are directed to a disposable container. Theinlet lumen230 is then reconnected to the whole blood source container, and the above-described batch process is repeated as many times as required until the desired quantity of platelets has been harvested.
An alternative embodiment of a disposable, flexible centrifuge bag having inner C-shaped seals is illustrated inFIG. 42 ascentrifuge bag320.Disposable centrifuge bag320 has a substantially flat, toroidal- or doughnut-shaped configuration having outer andinner perimeters322 and324, respectively, and comprises radially extending upper andlower sheets323,325 formed from a substantially flexible material. The upper andlower sheets323,325 are superimposed and completely sealed together atouter perimeter322 by an rf weld, heat weld or other comparable method of adhering-two surfaces.Inner perimeter324 definescore327 ofbag320.
Upper andlower sheets323,325 ofcentrifuge bag320 are further sealed at two portions between the outer perimeter and the inner perimeter. That is,centrifuge bag320 further comprises a first C-shapedseal326 located between the inner andouter perimeters322,324, and a second C-shaped seal328 located between the inner andouter perimeters322,324. The first and second C-shapedseals326,328 have their concave sides facing each other such that whencentrifuge bag320 is viewed from the top as inFIG. 36, first and second C-shapedseals326 and328 are mirror images of each other. First and second C-shapedseals326,328 together define anouter compartment348 between theouter perimeter322 and first and second C-shapedseals326 and328, wherein theouter compartment348 has a toroidal configuration. First and second C-shaped seals further define ancompartment350 between first and second C-shapedseals326,328 andinner perimeter324, wherein theinner compartment350 has a doughnut shaped configuration. The ends330 and332 of first C-shapedseal326 are slightly curved inward towards theinner core327, and likewise ends334 and336 of second C-shaped seal328 are slightly curved inward towards theinner core327. The first and second C-shapedseals326 and328 are positioned such that ends330 and334 of first and second C-shapedseals326,328, respectively, are directly opposite and spaced apart from each other, thereby definingfirst channel335 therebetween, and such that ends332 and336 of first andsecond seals326 and328, respectively, are directly opposite and spaced apart from each other, thereby definingsecond channel337 therebetween, wherein the first andsecond channels335 and337 are diametrically opposed. First andsecond channels335 and337 provide fluid communication between the outer and inner compartments.
Centrifuge bag320 further comprises aninlet port340, in thelower sheet325 for introducing fluid intoouter compartment348. Preferably theinlet port340 is spaced 90 degrees fromchannel335 however it could also be positioned at an angle greater or less than 90 degrees fromchannel335.Centrifuge bag320 further comprises first andsecond outlet ports344,346 inlower sheet325 and positioned withinchannels335 and337 for withdrawing a fluid compartment fromcentrifuge bag320.
In a preferred embodiment,centrifuge bag320 comprisesinlet tube338 secured to the outside surface ofupper sheet323 orlower sheet325 and radially extending from the center ofcore327 towards theouter perimeter322, whereininlet tube338 is fluidly connected at its distal end toinlet port340.Inlet port340 fluidly connectsinlet tube338 with theouter chamber348 ofcentrifuge bag320.Inlet tube338 is fluidly connected at its proximal end toumbilical cable228, preferably by an L-shaped connector (not shown). Further, in a preferredembodiment centrifuge bag320 comprisesoutlet tube342 secured to the outside surface ofupper sheet323 orlower sheet325 and extending across the diameter ofcore327, wherein one end ofoutlet tube342 is fluidly connected tofirst outlet port344 and the other end ofoutlet tube342 is fluidly connected tosecond outlet port346. Outlet tube is fluidly connected at its center toumbilical cable228 via a T-shaped connector (not shown).
In an alternative embodiment of this invention,centrifuge bag320 comprisesinlet tube338 sandwiched between upper andlower sheets323,325 and extending radially from the center ofcore327 towardsouter perimeter322, wherein inlet tube328 is fluidly connected at its distal end toinlet port340, andoutlet tube342 sandwiched between upper andlower sheets323,325 and extending across the diameter ofcore327, wherein one end ofoutlet tube342 is fluidly connected tooutlet port344 and the other end ofoutlet tube342 is fluidly connected tooutlet port346. When upper andlower sheets323,325 are sealed together atinner perimeter324, inlet andoutlet tubes338,342 are thereby sealed therebetween.Inlet tube338 andoutlet tube342 are fluidly connected to umbilical cable228 (not shown), which in this particular embodiment is a dual lumen tubing.
Centrifuge bag320 is removably secured betweenrotor base204 androtor cover206 ofrotor202 in a manner as described above so thatcentrifuge bag320 is held in a fixed position relative torotor base204 androtor cover206 during rotation of thecentrifuge rotor202. As will be appreciated by those of skill in the art, alternative embodiments of rotor base204 (FIG. 15) and rotor cover206 (FIG. 16) as discussed above with respect tocentrifuge bag270 will be required to accommodate the design of centrifuge bag370.
Centrifuge bag370 may be used for the separation and isolation of one or more components dissolved or suspended in a variety of fluid media, including, but not limited to, the separation of cellular components from biological fluids. For example, centrifuge bag370 is useful for the concentration and removal of platelets from whole blood. Therefore, the following description of the separation of platelets from whole blood usingcentrifuge bag320′ is merely for purposes of illustration and is not meant to be limiting of the use ofbag320. The separation of a fluid medium such as whole blood incentrifuge bag320 may be considered to be a one-stage separation process. With reference toFIG. 36, centrifugation of whole blood begins with the introduction of an aliquot of whole blood intocentrifuge bag320 throughinlet port340 viainlet tube338 during rotation of thecentrifuge20.Inlet tube338 is fluidly connected viainlet lumen230 ofumbilical cable228 to an anticoagulated whole blood source. As the aliquot of whole blood enters theouter chamber348 ofcentrifuge bag320, it quickly separates radially withinouter chamber348 into various fractions based on the densities of the components of the whole blood, including an outermost fraction containing the red blood cells which pack along theouter perimeter322 ofcentrifuge bag320, and inner fractions containing the platelets and plasma. Continued infusion of whole blood adds an additional volume of red blood cells and consequently pushes the fraction containing platelets inward. Additional infusions of whole blood will continue to push the platelet-containing fraction further inward until thechamber348 is substantially filled with red blood cells (the remainder of the volume being plasma), such that the platelet-containing fraction is pushed intochannels335,337 and into the vicinity ofoutlet ports344,346. As discussed above, the ends of C-shapedseals326,328 curve slightly inward, which both helps to funnel the platelet-containing fraction intochannels335,337, and to minimize the amount of red blood cells that flow intochannels335,337. The point at which the red blood cells are near the entrance ofchannels335,337 may be monitored either visually or by a sensor, as described below in detail. As the platelet-containing fraction enters the vicinity ofoutlet ports344,346, the infusion of whole blood is terminated, and suction or other drawing means is applied tooutlet tube342 to withdraw the platelet-containing fraction throughoutlet ports344,346.
After withdrawal of substantial portion of the platelet rich plasma,inlet lumen230 is disconnected from the whole blood source container and connected to a disposal container, after which the remaining components incentrifuge bag320 are evacuated through inlet port34 by applying suction toinlet tube276 and are directed to a disposal container. Theinlet lumen230 is then reconnected to the whole blood source container, and the above-described process is repeated as many times as required until the desired quantity of platelets has been harvested.
As can be appreciated, it may be desirable to maximize the surface area of separated fraction to be harvested, since this maximizes the amount of the fraction which may be collected without increasing the potential for introducing impurities into the separation (e.g., adjacent, lighter density components may begin moving into the region of the fraction being harvested), and without increasing the size of the centrifuge to an undesirable degree.
In order to maximize the amount of the desired component (e.g., platelet rich plasma, white blood cells, or platelet poor plasma) which may be harvested, one embodiment of a centrifuge container of this invention for the separation of components in a fluid medium (e.g., whole blood), shown inFIGS. 45-52, is designed to position the desired component (e.g., platelet rich plasma) the platelet rich plasma at a region within the fixed centrifuge container or centrifuge bag so that the desired fraction has a maximum horizontal surface area (i.e., width). Thus, another embodiment of this invention comprises acentrifuge container500 shown inFIG. 45.FIG. 45 is a side cross-sectional view of arigid container500 comprising a rigid,annular body510 having anaxial core600 that is closed at thetop end610 and opened at thebottom end620.Rigid container500 further comprises aninterior collection chamber580 for receiving and holding the fluid medium to be centrifuged and having anouter perimeter585 and aninner perimeter590. The side, cross-sectional profile ofchamber580 is generally an off-centered “figure eight” or “dumbbell” shape, as shown inFIG. 46. As used herein, “figure eight” or “dumbbell” shaped means that the height of section A is approximately equal to the height of section C, and the heights of sections A and C are greater that the height of section B. Furthermore, as used herein, “off-center” means that the width W1from the center of section B toouter perimeter585 is less than the width W2from the center of section B toinner perimeter590 as shown inFIGS. 45 and 46.
Rigid container500 further comprisesinlet channel550 extending radially fromcore600 to a point near theouter perimeter585 and is fluidly connected at its distal end with the outer area ofchamber580.Rigid container500 further comprisesoutlet channel554 extending radially fromcore600 to the more central portion of chamber580 (i.e., the narrow portion or “neck” of the figure eight cross-section) and is fluidly connected at its distal end withchamber580. While the inlet andoutlet channels550,554 are shown inFIG. 45 as being fluidly connected to the top end ofchamber580, the present invention also includes embodiments wherein bothchannels550,554 are in fluid communication with the bottom end ofchamber580, or whereinchannel550 is in fluid communication with the top end ofchamber580 andchannel554 is in fluid communication with the bottom end ofchamber580, or vice versa. Inlet andoutlet channels550,554 are fluidly connected todual lumen tubing228 having aninlet lumen230 and anoutlet lumen232.Rigid container500 is removably secured to theupper surface133 ofupper bearing assembly130 with appropriate screws, fasteners or the like (not shown).Inlet lumen230 may be connected to a source for fluid-medium, andoutlet lumen232 may be connected to a suction means for withdrawing the desired fraction from thechamber580.
The configuration ofchamber580 is specifically designed to maximize the collection of platelet rich plasma by centrifugation of anticoagulated whole blood. More particularly, the shape ofchamber580 increases the width of the platelet rich plasma fraction when viewed from the top and decreases the depth of the platelet rich plasma fraction when viewed from the side, thus allowing the withdrawal of a greater amount of platelet rich plasma. This unique design can be better explained by comparingFIGS. 44 and 47.FIG. 44 shows a side profile of arigid centrifuge container500 as shown inFIG. 43, having a generally oval profile and containing whole blood that has been separated into four fractions by centrifugation. InFIG. 44, width W3indicates the relative horizontal width of the platelet rich plasma fraction to be harvested, and D1indicates the relative depth of the platelet rich plasma fraction.FIG. 47 shows a side profile ofrigid centrifuge container580 of this invention having the above-described off-centered figure eight shape and containing whole blood that has been separated into four fractions by centrifugation. InFIG. 47, width W4indicates the relative horizontal width of the plateletrich plasma fraction260 to be harvested, and D2indicates the relative depth of the plateletrich plasma fraction260. Width W4is necessarily wider than width W3inFIG. 44. Thus it can be easily appreciated that upon withdrawal of the plateletrich plasma fraction260 from the oval shaped container shown inFIG. 44, plateletpoor plasma fraction262 will shift closer to theoutlet tube554 relatively quickly. In contrast the dumbbell shaped profile ofchamber580 shown inFIG. 47 significantly increases the width W4while decreasing the average depth D2, and therefore a greater portion of the plateletrich plasma fraction260 can be withdrawn with greater accuracy before the plateletpoor plasma fraction262 reaches theoutlet tube554.
In an embodiment where the platelet rich plasma is to be collected one could designchamber580 as follows. The configuration ofchamber580, that is, the relative heights A, B, and C as shown inFIG. 46, will be determined based on the typical location of the plateletrich plasma fraction260 after centrifugation of whole blood. For example, in arigid centrifuge container500 as illustrated inFIG. 45, havingchamber580 with a 30 ml capacity and a radius of approximately 65 mm measured from its rotational axis to theedge630, the platelet rich plasma will collect inchamber580 at a region at a radial position ranging from about 35 to about 60 mm from the axis. In this region of thechamber580, as illustrated inFIG. 46, thechamber580 has a height of about 10 mm such that the horizontal surface area “B” of this region, illustrated inFIG. 46, is about 4 mm2. Consequently, it can be appreciated that because of the unique configuration ofchamber580, the surface area of the plateletrich plasma fraction260 as illustrated inFIG. 47 may be maximized without undesirably increasing the overall size of therigid centrifuge container500. It will be appreciated by those skilled in the art that various geometric designs may be utilized depending on the fluid medium being centrifuged and the cellular fraction to be collected. The process for harvesting platelets from whole blood usingrigid container500 may be achieved in a manner similar to that described forbag226
Rigid centrifuge container500 may be made from any number of rigid, transparent materials that are capable of withstanding typical sterilization conditions, including but not limited to acrylic resins, polycarbonate, or any clear thermal plastic. Preferablyrigid container500 is made of a cost-effective material that is relatively inexpensive to dispose of.
An alternate embodiment of a centrifuge rotor of this invention for holdingflexible centrifuge bag226 is illustrated inFIGS. 48-52. Generally and referring toFIGS. 48 and 49, thecentrifuge rotor755 is defined by a rotor base760 (FIGS. 48,50 and52) having alower channel780, and a rotor cover770 (FIGS. 49 and 51) having anupper channel782. The annular interior chamber784 (FIG. 48) ofrotor755 is defined by lower andupper channels780,782, and has a generally off-centered figure eight side cross-sectional configuration specifically designed to maximize the collection of platelet rich plasma by centrifugation of anticoagulated whole blood, as discussed below in detail.
As illustrated inFIGS. 51 and 52,rotor base760 comprises raisedannular rim775 and raisedcolumn786 which is axially disposed in the interior ofrotor base760. Raisedcolumn786 further has a groove790 (FIG. 52) extending the diameter ofcolumn786. The height ofrim775 is equal to the height ofcolumn786. As illustrated inFIG. 51,rotor cover770 comprises raisedannular rim777 and raisedcolumn788 which is axially disposed in the interior ofcover770. Raisedcolumn788 further has a groove792 (FIG. 52) extending the diameter ofcolumn788. The height ofrim777 is equal to the height ofcolumn788.Rotor base760 androtor cover770 are preferably made from any number of rigid transparent materials including, but not limited to acrylic resins, polycarbonate, or any clear thermal plastic.
Whencentrifuge rotor755 is to be assembled for use, flexible, doughnut-shapedcentrifuge bag226 having acenter core242 is placed inrotor base760 such thatcenter column786 preferably, but not necessarily, extends through the core ofcentrifuge bag226, and inlet andoutlet tubes248,250 ofbag226 are seated ingroove790.Rotor cover770 is superimposed onrotor base760 such thatgrooves790 and792 are aligned and further so that inlet andoutlet tubes248,250 are seated ingroove792. In one embodiment, whencover770 is appropriately secured to base760 (e.g., with screws, clamps, or the like), rims775 and777 are in complete contact with each other, andcolumns786 and788 are preferably in complete contact with each other, thereby creating chamber784 (FIG. 48). Alternatively whencover770 is secured to base760 as described, the inner perimeter ofbag226 is secured betweencolumns786 and788 such that the columns do not physically contact each other.
When the generally flat,flexible centrifuge bag226 is contained withinchamber784 prior to the infusion of a fluid medium (e.g., whole blood), it will not fill the entire volume ofchamber784 but rather will have a radially extending, flat shape ascentrifuge rotor755 is spinning. However, after a sufficient volume of the fluid medium (e.g., whole blood) has been introduced intoflexible bag226 throughinlet tube248 such thatbag226 is substantially completely filled, it will be appreciated that filledcentrifuge bag226 will conform to the shape ofchamber784 and consequently will have a off-centered figure eight shaped cross-section.
The off-centered figure eight configuration of thechamber784 is of approximately the same configuration as therigid bag500. Therefore, for the same reasons, the shape of chamber784 (and consequently the shape of filled bag226), will assume an off-centered figure eight shape wherein the width of the platelet rich plasma fraction is greatly increased relative to the width of a filled bag having an elliptical cross-sectional shape (see, for example,FIGS. 46 and 47).
As discussed above, a number of methods may be utilized to gauge the harvesting of the desired fraction (such as, but not limited to, platelet rich plasma) from the centrifuge bag. For instance, the separation of platelet rich plasma fraction may be indicated by visual observation of a concentric ring containing the platelet rich plasma (which will be a less colored fraction) and an outer red-colored concentric ring containing the red blood cells. In this case, when such fraction(s) have been separated, the platelet rich plasma may be withdrawn fromcentrifuge bag226 bybent fitting160 to direct the platelet rich plasma to the appropriate collector.
As an alternative to the foregoing, sensors may be incorporated as discussed in detail below to detect the presence of the platelet rich plasma fraction.
Based upon the foregoing, it can be appreciated that thecentrifugal processing system10 and the centrifuge rotors and bags of this invention have a plurality of features which are suited to harvesting platelet rich plasma, white blood cells, platelet poor plasma or red blood cells from a patient's whole blood in accordance with each of the aspects of the present invention. For example, as discussed above, hematocrits (the volume of blood occupied by red blood cells, expressed as a percentage) vary from individual to individual. Thus, depending on the amount of red blood cells present in a particular sample, the exact radial location of various blood components within the centrifuge bag after centrifugation will also vary. The centrifuge bags of this invention overcome this issue by having an inlet tube capable of not only introducing whole blood into the centrifuge bag, but also capable of withdrawing some of all of the red blood cell fraction as needed to shift the location of the fraction to be harvested into the area of the outlet tube. Such features are presented incentrifuge bags226,270,320 and500. Yet another embodiment of the centrifuge bags of this invention which overcomes problems with varying hematocrits iscentrifuge bag226′ having multiple outlet tubes.
Additionally, thecentrifugal processing system10 effectively provides a closed system which enhances the potential for maintaining a desired degree of sterility associated with the entire procedure since materials can thus be both provided to and removed from the centrifuge bag during rotation of the centrifuge via, for instance, a dual lumen tubing connected to a fluid source (e.g., anticoagulated whole blood withdrawn from a patient before or during surgery) and collection containers (i.e., for the preparation of a platelet gel), without interrupting the process, and thus without significant exposure of the materials to environmental conditions.
Moreover, the portable size of thecentrifugal processing system10 in combination with the above-described features of shifting the separated fractions and maximizing the surface area of the harvested fraction allows for increased processing capabilities autologous platelet gel over larger, conventional centrifuges
The on-line harvesting capabilities of thecentrifugal processing system10 allows for continuous, dynamic separation and collection of platelet rich plasma, white blood cells, red blood cells and platelet poor plasma, by adjusting the input and removal of fluid medium and separated fractions as described above. Further, the orientation of the flexible and rigid centrifuge bags of this invention and of the contents therein (e.g., being generally radially extending) is not significantly modified in the transformation from separation to harvesting of the various constituents. Moreover, vortexing throughout the contents of the centrifuge bags of this invention is reduced or eliminated since thecentrifugal processing system10 does not have to be decelerated or stopped for addition of fluid medium or removal of the various fractions therefrom.
Further, the general orientation of the flexible and rigid centrifuge bags of the invention (e.g., substantially horizontal) is maintained during removal of the desired whole blood fraction similar to the orientation of the centrifuge bags assumed during centrifugation to further assist in maintaining the degree of separation provided by centrifugation. Consequently, the potential is reduced for disturbing the fractions to the degree where the separation achieved is adversely affected.
Although the present invention has been described with regard to the separation of whole blood components, it will be appreciated that the methods and apparatus described herein may be used in the separation components of other fluid media, including, but not limited to whole blood with density gradient media; cellular components, or sub-sets of the four whole blood components previously defined.
While blood separation and materials handling may be manually controlled, as discussed above, a further embodiment of the present invention provides for the automation of at least portions of the separation and material handling processes. Referring toFIG. 53, an automated centrifugal processing system800 is illustrated that is generally configured to provide automated control over the steps of inputting blood, separating desired components, and outputting the separated components. The following discussion of the processing system800 provides examples of separating platelets in a blood sample, but the processing system800 provides features that would be useful for separating other components or fractions from blood or other fluids. These other uses for the processing system800 are considered within the breadth of this disclosure. Similarly, the specific components discussed for use in the processing system800 are provided for illustration purposes and not as limitations, with alternative devices being readily apparent to those skilled in the medical device arts.
In the embodiment illustrated inFIG. 53, the processing system800 includes ablood source802 connected with afluid line804 to aninlet pump810. Avalve806, such as a solenoid-operated valve or a one-way check valve, is provided in thefluid line804 to allow control of flow to and from theblood source802 during operation of theinlet pump810. Theinlet pump810 is operable to pump blood from theblood source802 through thefluid line818 to acentrifuge20. Once all or a select portion of the blood in theblood source802 have been pumped to a blood reservoir824 of the centrifuge820 theinlet pump810 is turned off and theblood source802 isolated withvalve806. Theinlet pump810 may be operated at later times to provide additional blood during the operation of the processing system800 (such as during or after the removal of a separated component).
Thecentrifuge20 preferably includes a flexible centrifuge bag, for example226,226′,270, or320, positioned within therotor202 for collecting the input blood, or alternativelyrotor202 may be a rigid container having an off centered figure eight shaped chamber, which may collect blood directly as discussed previously. Thus, while the embodiment described below illustrates acentrifuge having bag226, it is to be understood that the alternative centrifuge bags disclosed herein may be used in a similar manner. Thecentrifuge20 as discussed above has an internalmid-shaft gear assembly108 that provides the motive force to rotate therotor assembly200, and particularly therotor202, at a rotation rate that is adequate to create centrifugal forces that act to separate the various constituents or components of the blood in therotor202. Thedrive assembly822 may comprise a number of devices useful for generating the motive force, such as an electric motor with a drive shaft connected to internal drive components of thecentrifuge20. In a preferred embodiment, thedrive assembly822 comprises an electric motor that drives a belt attached to an exterior portion of thecentrifuge20 and more particularly to thetiming belt ring44. To obtain adequate separation, the rotation rate is typically between about 0 RPM and 5000 RPM, and in one embodiment of the invention, is maintained between about 0 RPM and 5000 RPM.
As discussed in detail previously, components of particular densities assume radial positions or belts at differing distances from the central axis A of therotor202. For example, the heavier red blood cells typically separate in an outer region while lower density platelets separate into a region more proximal to the central axis of therotor202. Between each of these component regions, there is an interface at which the fluid density measurably changes from a higher to a lower density (i.e., as density is measured from an outer to an inner region), and this density interface is used in some embodiments of the centrifugal processing system800 to identify the location of component regions (as will be discussed in more detail below). In a preferred embodiment, thedrive assembly822 continues to operate to rotate thecentrifuge20 to retain the separation of the components throughout the operation of the centrifugal processing system800.
Once blood separation has been achieved within therotor202, the outlet pump830 is operated to pump select components from therotor202 throughoutlet lumen828. As discussed previously, in relation to the features of the disposableblood centrifuge bag226, the centrifuge bag held within therotor202 preferably is configured to allow the selective removal of a separated blood component, such as platelets located in a platelet rich plasma region, by the positioning of an outlet lumen232 a radial distance from the central axis of thecentrifuge bag226. Preferably, this radial distance or radial location for the outlet lumen is selected to coincide with the radial location of the desired, separated component or the anticipated location of the separated component. In this manner, the outlet pump830 only (or substantially only) removes a particular component (such as platelets into container400) existing at that radial distance. Once all or a desired quantity of the particular component is removed from thecentrifuge bag226, operation of the outlet pump830 is stopped, and a new separation process can be initiated. Alternatively, in a preferred embodiment, additional blood is pumped into the centrifuge by226 by further operating theinlet pump810 after or concurrent with operation of the outlet pump830.
A concern with fixing the radial distance or location of the outlet port is that each blood sample may have varying levels or quantities of different components. Thus, upon separation, the radial distance or location of a particular component or component region within thecentrifuge bag226 varies, at least slightly, with each different blood sample. Additionally, because of the varying levels of components, the size of the component region also varies and the amount that can be pumped out of thecentrifuge bag226 by the outlet pump830 without inclusion of other components varies with each blood sample. Further, the position of the component region will vary in embodiments of the separation system800 in which additional blood is added after or during the removal of blood by the outlet pump830.
To address the varying location of a particular separated component, the centrifugal processing system800 preferably is configured to adjust the location of a separated component to substantially align the radial location of the separated component with the radial location of the outlet port. For example, the centrifugal processing system800 may be utilized to collect platelets from a blood sample. In this example, the centrifugal processing system800 preferably includes a redblood cell collector812 connected to theinlet pump810 viafluid line814 having an isolation valve816 (e.g., a solenoid-operated valve or one-way check valve). Alternatively, the pump or syringe may also act as the valve. Theinlet pump810 is configured to selectively pump fluids in two directions, to and away from the centrifuge820 throughfluid line818, and in this regard, may be a reversible-direction peristaltic pump or other two-directional pump. Similarly, although shown schematically with twofluid lines804 and814, a single fluid line may be utilized as an inlet and an outlet line to practice the invention.
Operation of theinlet pump810 to remove fluid from thecentrifuge bag226 is useful to align the radial location of the desired separated component with theoutlet tube250 andinlet tube248 of thecentrifuge bag226. When it is desired to align platelets or platelet rich plasma with theoutlet tube250, theinlet tube248 connected to lumen232 and230, respectively,inlet tube248 is preferably at a greater radial distance than theoutlet tube250. When suction is applied to theinlet lumen230 byinlet pump810, red blood cells are pumped out of thecentrifuge bag226 and into the redblood cell collector812. As red blood cells are removed, the separated platelets (i.e., the desired component region) move radially outward to a new location within thecentrifuge bag226. Theinlet pump810 is operated until the radial distance of the separated platelets or platelet region from the central axis is increased to coincide with the radial distance or location of theoutlet tube250 of thecentrifuge bag226. Once substantial alignment of the desired component region and theoutlet tube250 is achieved, the outlet pump830 is operated to remove all or a select quantity of the components in the aligned component region.
To provide automation features of the invention, the centrifugal processing system800 includes acontroller850 for monitoring and controlling operation of theinlet pump810, thecentrifuge20, thedrive assembly822, and the outlet pump830. Numerous control devices may be utilized within the centrifugal processing system800 to effectively monitor and control automated operations. In one embodiment, thecontroller850 comprises a computer with a central processing unit (CPU) with a digital signal processor, memory, an input/output (I/O) interface for receiving input and feedback signals and for transmitting control signals, and software or programming applications for processing input signals and generating control signals (with or without signal conditioners and/or amplifiers). Thecontroller850 is communicatively linked to the devices of the centrifugal processing system800 withsignal lines860,862,864,866, and868 which may include signal conditioning devices and other devices to provide for proper communications between thecontroller850 and the components of the centrifugal processing system800.
Once blood is supplied to theblood source container802, the operator pushes the start button and thecontroller850 transmits a control signal oversignal line864 to thedrive assembly822, which may include a motor controller, to begin rotating thecentrifuge20 to cause the components of the blood incentrifuge bag226 to separate into radially-positioned regions (such as platelet rich plasma regions). After initiation of the centrifuge spinning or concurrently with operation of thedrive assembly822, thecontroller850 generates a control signal oversignal line860 to theinlet pump810 to begin pumping blood from theblood source container802 to thecentrifuge bag226 of thecentrifuge20. In some embodiments of the processing system800, thedrive assembly822 is operable at more than one speed or over a range of speeds. Additionally, even with a single speed drive shaft the rotation rate achieved at thecentrifuge20 may vary. To address this issue, the processing system800 may include avelocity detector858 that at least periodically detects movement of thecentrifuge bag226 portion of thecentrifuge20 and transmits a feedback signal oversignal line866 to thecontroller850. Thecontroller850 processes the received signal to calculate the rotation rate of thecentrifuge20, and if applicable, transmits a control signal to thedrive assembly822 to increase or decrease its operating speed to obtain a desired rotation rate at thecentrifuge bag226.
To determine when separation of the components in thecentrifuge bag226 is achieved, the processing system800 may be calibrated to account for variations in thecentrifuge20 and drive assembly822 configuration to determine a minimum rotation time to obtain a desired level of component separation. In this embodiment, thecontroller850 preferably includes atimer mechanism856 that operates to measure the period of time that thecentrifuge20 has been rotated by the drive assembly822 (such as by beginning measuring from the transmission of the control signal by thecontroller850 to the drive assembly822). When the measured rotation time equals the calibrated rotation time for aparticular centrifuge20 and drive assembly822 configuration, thetiming mechanism856 informs thecontroller850 that separation has been achieved in thecentrifuge bag226. At this point, thecontroller850 operates to transmit control signal oversignal line860 to theinput pump810 to cease operation and to the outlet pump830 oversignal line868 to initiate operation to pump a separated component in the component region adjacent the outlet port oflumen232 ofcentrifuge bag226 throughfluid line828. In another embodiment where rotation time is utilized bycontroller850, the velocity feedback signal from thevelocity detector858 is utilized by thecontroller850 to adjust the rotation time as necessary to obtain the desired level of component separation. For example, the centrifugal processing system800 can be calibrated for a number of rotation rates and the corresponding minimum rotation times can be stored in a look up table for retrieval by thecontroller850 based on a calculated rotation rate. Rotational rates may be varied either manually or automatically to optimize cellular component position and or concentration.
Because the location of component separation regions varies during separation operations, a preferred embodiment of the centrifugal processing system800 includes asensor assembly840 to monitor the separation of components within the centrifuge bag and to transmit feedback signals overline862 to thecontroller850. As will be understood by those skilled in the art, numerous sensor devices exist for detecting the presence of certain components in a fluid, and specifically a blood, sample. Many of these devices comprise a source of radiant energy, such as infrared, laser, or incandescent light, and a compatible radiant energy-sensitive detector that reacts to the received energy by generating an electric signal. Briefly, these radiant energy devices are useful because the detected signal varies in a measurable fashion with variances in the density of the material through which beams of the radiant energy are passed. According to the invention, thesensor assembly840 may comprise any of these well-known types of radiant energy source and detector devices and other sensor devices useful for measuring the existence of constituents of fluids such as blood.
The source and the detector of thesensor assembly840 are preferably located within the centrifugal processing system800 to allow monitoring of thecentrifuge bag226 and, particularly, to identify the presence of a particular blood component in a radial position coinciding with the radial position of the outlet port of thecentrifuge bag226. In one embodiment, the radiation beams from the source are transmitted through a “window” in thecentrifuge bag226 that has a radial location that at least partially overlaps the radial location of the outlet port. During operation of the centrifugal processing system800, the feedback signals from the detector of thesensor assembly840 allow thecontroller850 to identify when a density interface has entered the window. This may occur for a number of reasons. The change in density may occur when red blood cells are being removed by operation of theinlet pump810 to remove fluid from thecentrifuge bag226 via theinlet tube248. The change in density may also occur when a denser component is being added to thecentrifuge bag226 causing the particular blood component to be pushed radially inward. In the centrifugation of whole blood, this occurs when additional blood is added by operation of theinput pump810 and red blood cells collect in a region radially outward from the platelet region.
To account for differing movement of the density interface, the window of the radiation source may be alternatively positioned radially inward from the location of theoutlet tube250 of thecentrifuge bag226. By positioning the window inward from theoutlet tube250, thecontroller850 can identify when the outlet pump830 has nearly removed all of the particular component of the monitored region and/or when theinlet pump810 has removed a quantity of denser components causing the monitored region to move radially outward. Thecontroller850 can then operate to send control signals to turn off the outlet pump830 or the inlet pump810 (as appropriate) to minimize the amount of undesired components (lower density components) that enter theoutlet tube250. Alternatively, thesensor assembly840 may have two radiation sources and detectors, and the second window of thesensor assembly840 may be located a distance radially outward from theoutlet tube250. With two sensing windows, thesensor assembly840 is operable to provide thecontroller850 information about a density interface moving radially inward toward the outlet tube250 (such as when red blood cells are added). In response, thecontroller850 can generate a control signal to theinlet pump810 to operate to pump the denser components, such as red blood cells, out of thecentrifuge bag226. Two sensing windows also allow thecontroller850 to detect a density interface moving outward, which allows thecontroller850 to shut off the outlet pump830 (and/or theinlet pump810 to stop evacuating processes) and/or to start theinlet pump810 to add additional blood.
To further clarify operation of the processing system800,FIG. 54 is provided which illustrates the timing and relationship of control signals generated by thecontroller850 and the receipt of feedback signals from thesensor assembly840. In this embodiment, the radiation detector of thesensor assembly840 is positioned adjacent outlet tube (inlet to the outlet pump830) in thecentrifuge bag226 to sense density changes in the fluid flowing past theoutlet tube250. As illustrated, operation of the processing system800 begins at time to, with theinlet pump810, the outlet pump830, and thecentrifuge drive assembly822 all being off or not operating. At time t1, thecontroller850 operates in response to operator input or upon sensing theblood source802 is adequately filled (sensor not shown) to generate a control signal online864 to begin operating thecentrifuge drive assembly822 to rotate thecentrifuge bag226. In some embodiments, this control signal overline864 also contains rotation rate information to initially set the operating speed of thedrive assembly822. Concurrently or at a selected delay time, thecontroller850 generates a control signal online860 to start theinlet pump810 in a configuration to pump fluid to thecentrifuge bag226 overfluid line818. Thesensor assembly840 provides an initial density feedback signal to thecontroller850 online862, which thecontroller850 can process to determine an initial or unseparated density adjacent the outlet tube. Alternatively, thecontroller850 may be configured to request a feedback signal from thesensor assembly840 after a set delay period (as measured by the timer mechanism856) to allow separation of the components being pumped into the centrifuge bag226 (such as the calibrated, minimum rotation time discussed above) into regions.
At time t2, thecontroller850 functions to align the region having the desired density, such as a region comprising a higher density of platelets, adjacent the detector of the sensor assembly840 (i.e., adjacent the outlet tube). To achieve alignment, thecontroller850 transmits a control signal overline860 to theinlet pump810 to stop pumping fluid to thecentrifuge bag226, to reverse pumping directions including shuttingvalve806 andopening valve816, and to begin pumping components having a higher density then the particular, desired component from thecentrifuge bag226 to thecollector812. For example, when thecentrifugal processing system10 is operated to separate and collect platelets or platelet rich plasma, theinlet pump810 at time, t2, is operated to pump out the red blood cell fraction by applying suction at theinlet tube248 to thecentrifuge bag226. At time t3, the density of the fluid adjacent theoutlet tube250 begins to change as denser components are removed by theinlet pump810, and the sensor feedback signal being transmitted to thecontroller850 changes in magnitude. The sensor feedback signal continues to change in magnitude (either becoming stronger or weaker depending on the particular sensor utilized and the material being collected) until at time t4, when thecontroller850 processes the feedback signal and determines that the density of the adjacent fluids is within a desired range. This transition can also be thought of as detecting when an interface between two regions of differing densities passes by the location of the detector of thesensor assembly840.
With the region of the desired, separated component aligned with theoutlet tube250, thecontroller850 operates at time t4, to send a control signal overline860 to stop operations of theinlet pump810. Also, at time t4, or at any time thereafter, thecontroller850 generates a control signal overline868 to begin operation the outlet pump830 to apply suction at theoutlet tube250 of thecentrifuge bag226 to remove the desired component, such as the platelet rich plasma fraction, from thecentrifuge bag226. At time t5, the sensor feedback signal again begins to change in magnitude as the density of the fluid near theoutlet tube250 begins to change, such as when platelet poor plasma begins to enter the sampling window of thesensor assembly840. At time t6, the density of the fluid adjacent theoutlet tube250 and, hence, in the sampling window is outside of a desired density range (e.g., the fluid has less than a predetermined percentage of platelets or other desired fluid component). In response, thecontroller850 transmits a control signal online868 to halt operations of the outlet pump830. Of course, thecontroller850 can be operated to transmit the signal to the outlet pump830 at any time prior to time t6, such as at a time after time t5, when the density of the adjacent fluid begins to change but prior to time t6or based on volume removed. Thecontroller850 can then operate any time after time t6, to halt operation of thecentrifuge drive assembly822. Further, as discussed above, operations of the separation centrifugal processing system800 can be repeated with theinlet pump810 being operated to add additional fluid, e.g., blood, after time tr. Alternatively, theinlet pump810 and the outlet pump830 may be operated concurrently to add an additional volume of blood with a corresponding new amount of the component being collected after time t4, to extend the period of time between detection of the interface at time t4and the detection of an out of range density at time t6.
In the above discussion of the automated processing system800, asensor assembly840 was shown inFIG. 53 schematically, and it was noted that the location of a radiant energy source and a detector may be any location within the processing system800 useful for obtaining an accurate measurement of separating blood components within thecentrifuge bag226. For example, the source and detector can be both positioned within thecentrifuge20 at a location adjacent thecentrifuge bag226. In this embodiment, problems may arise with providing proper signal and power line connections to the source and sensor and with accounting for the rotation of the centrifuge and portions of thesensor assembly840. Hence, one preferred embodiment of the processing system800 provides for an externally positionedsensor assembly840 including source and detector to simplify the structure of thecentrifuge20 while still providing effective density determinations of fluids within the blood reservoir.
FIG. 55 illustrates a general side view of the relevant components of this external sensor embodiment of the centrifugal processing system800. Generally, thecentrifuge20 comprises arotor extension portion880 and adrive portion881, which is connected to the drive assembly822 (connection not shown). Both thecentrifuge20 and therotor extension portion880 rotate about a central or rotation axis, caxis, of thecentrifuge20. As discussed in more detail with respect to the internal gearing features of thecentrifuge20, thedrive portion881 spins in a ratio of 2 to 1 (or other suitable ratio) relative to thereservoir extension portion880 to control twisting of inlet and outlet fluid lines to therotor extension portion880. The internal gearing features of thecentrifuge20 also enable thecentrifuge20 to effectively obtain rotation rates that force the separation of components with differing densities while limiting the risk that denser components, such as red blood cells, will become too tightly packed during separation forming a solid, dense material that is more difficult to pump or remove from thecentrifuge20.
Referring again toFIG. 55, therotor extension portion880 is shown located on the upper end of thecentrifuge20 and includes acentrifuge bag226 or other receptacle. Preferably, therotor extension portion880 is fabricated from a transparent or partially transparent material, such as any of a number of plastics, to allow sensing of fluid densities. Therotor extension portion880 extends a distance, dover, beyond the outer edge of thecentrifuge20 as measured radially outward from the central axis, caxis. The distance, dover; is preferably selected such that the desired component, such as the platelet rich plasma fraction, to be collected readily separates into a region at a point within thecentrifuge bag226 that also extends outward from thecentrifuge20. In this regard, therotor extension portion880 is also configured so that thecentrifuge bag226 extends within therotor extension portion880 to a point near the outer circumference of therotor extension portion880. The distance, dover, selected for extending therotor extension portion880 is preferably selected to facilitate alignment process (discussed above) and to control the need for operating theinput pump810 to remove denser components. In one embodiment, the distance, dover, is selected such that during separation of a typical blood sample center of the platelet rich region is about one half the extension distance, dover, from the circumferential edge of thecentrifuge20.
Thesensor assembly840 is entirely external to thecentrifuge20 as shown inFIG. 55. Thesensor assembly840 includes asource882 for emittingbeams884 of radiant energy into and through therotor extension portion880 and the includedcentrifuge bag226. Again, as discussed previously, theradiant energy source882 may be nearly any source of radiant energy (such as incandescent light, a strobe light, an infrared light, laser and the like) useful in a fluid density sensor and the particular type of detector or energy used is not as important as the external location of thesource882. Thesensor assembly840 further includes adetector886 that receives orsenses beams888 that have passed through thecentrifuge bag226 and have impinged upon thedetector886. Thedetector886 is selected to be compatible with thesource882 and to transmit a feedback signal in response sensing the energy beams888. The detector886 (in combination with thecontroller850 and its processing capacities) is useful for detecting the density of fluids in thecentrifuge bag226 between thesource882 and thedetector886. Particularly, thesensor assembly840 is useful for identifying changes in fluid density and interfaces between fluids with differing densities. For example, the interface between a region containing separated red blood cells and a region containing the platelet rich plasma fraction, and the interface between the platelet rich plasma region and a platelet-poor plasma region.
With some source and detector configurations, a sampling window is created rather than a single sampling point (although a single sampling point configuration is useful as part of the invention as creating a window defined by a single radial distance). The sampling window is defined by an outer radial distance, dOUT, from the central axis, caxisand an inner radial distance, dIN. As may be appreciated, for many source and detector configurations the size of the sampling window may be rather small approximating a point and may, of course vary in cross-sectional shape (e.g., circular, square, rectangular, and the like). As discussed previously, it is preferable that thesensor assembly840 be positioned relative to thereservoir extension portion880 and thecentrifuge bag226 such that the sampling window created by thesource882 anddetector886 at least partially overlaps the radial position of the region created during separation processes containing a component of particular density, such as platelets. This may be a calibrated position determined through calibration processes of thecentrifuge20 in which a number of blood (or other fluid) samples are fully separated and radial distances to a particular region are measured. The determined or calibrated position can then be utilized as a initial, fixed location for thesensor assembly840 with thesource882 anddetector886 being positioned relative to therotor extension portion880 such that the sampling window overlaps the anticipated position of the selected separation region. Of course, each sample may vary in content of various components which may cause this initial alignment to be inaccurate and operations of the centrifugal processing system800 may cause misalignment or movement of regions. Hence, alignment processes discussed above preferably are utilized in addition to the initial positioning of the sampling window created by thesensor assembly840.
In an alternate embodiment, thesensor assembly840 is not in a fixed position within the separation system800 and can be positioned during separation operations. For example, thesensor assembly840 may be mounted on a base which can be slid radially inward toward thecentrifuge20 and radially outward away from thecentrifuge20 to vary the distances, dINand dOUT. This sliding movement is useful for providing access to thecentrifuge bag226, such as to insert and remove a disposable bag. During operation, thesensor assembly840 would initially be pushed outward from thecentrifuge20 until a new bag was inserted into thecentrifuge bag226. Thesensor assembly840 could then be slid inward (or otherwise moved inward) to a calibrated position. Alternatively, the centrifugal processing system800 could be operated for a period of time to achieve partial or full separation (based on a timed period or simple visual observation) and then thesensor assembly840 slid inward to a position that the operator of the centrifugal processing system800 visually approximates as aligning the sampling window with a desired region of separated components (such as the platelet rich plasma region). The effectiveness of such alignment could then readily be verified by operating thesensor assembly840 to detect the density of the fluids in thecentrifuge bag226 and a calculated density (or other information) could be output or displayed by thecontroller850. This alternate embodiment provides a readily maintainable centrifugal processing system800 while providing the benefits of a fixedposition sensor assembly840 and added benefits of allowing easy relative positioning to obtain or at least approximate a desired sample window and separation region alignment.
In some situations, it may be preferable to not have arotor extension portion880 or to modify therotor extension portion880 and thesensor assembly840 such that the extension is not significant to monitoring the separation within the blood reservoir orcentrifuge bag226. Two alternative embodiments or arrangements are illustrated inFIGS. 56 and 57 that provide the advantages of an external sensor assembly840 (such as an external radiation source and detector). With these further embodiments provided, numerous other expansions of the discussed use of an external sensor will become apparent to those skilled in the arts and are considered within the breadth of this invention.
Referring toFIG. 56, arotor202 is illustrated that has no extending portion (although some extension may be utilized) and contains thecentrifuge bag226. Again, therotor202 andcentrifuge bag226 are preferably fabricated from plastics or other materials that allow radiation to pass through to detect changes in densities or other properties of fluid samples within thecentrifuge bag226. In this embodiment of thesensor assembly840, theradiation source882 and thedetector886 are not positioned on opposing sides of therotor202. Instead, a reflector885 (such as a mirror and the like) is positioned within thedrive portion881 of the centrifuge to receive the radiation beams884 from theradiation source882 and direct them through theportion880 andcentrifuge bag226. Thedetector886 is positioned within thesensor assembly840 and relative to thecentrifuge20 to receive the deflected or reflectedbeams888 that have passed through the fluid sample in thecentrifuge bag226. In this manner, the sampling window within thecentrifuge bag226 can be selected to align with the anticipated location of the fraction that is to be collected upon separation. In a preferred embodiment, the sampling window at least partially overlaps with the location of the outlet tube of the blood reservoir orcentrifuge bag226.
In one embodiment, the drive portion is fabricated from a non-transparent material and a path for thebeams884 from theradiation source884 to thereflector885 is provided. The path in one preferred embodiment is an opening or hole such asport154 or156 (FIG. 14) in the side of thedrive portion881 that creates a path or tunnel through which thebeams884 travel unimpeded. Of course, the opening may be replaced with a path of transparent material to allow the beams to travel to thereflector885 while also providing a protective cover for the internals of thedrive portion881. A path is also provided downstream of thereflector885 to allow thebeams884 to travel through thedrive portion881 internals without or with minimal degradation. Again, the path may be an opening or tunnel through the drive portion leading to theportion202 or be a path created with transparent materials. Thebeams884 in these tunnel path embodiments enter thedrive portion881 one time per revolution of thedrive portion881, which provides an acceptable rate of sampling. Alternatively, areflector885 may readily be provided that extends circumferentially about the center axis of thedrive portion881 to provide a sampling rate equivalent to the rate ofbeam884 transmission. Of course, the positions of theradiation source882 and thedetector886 may be reversed and the angle of thereflector885 and transmission of thebeams884 may be altered from those shown to practice the invention.
A further embodiment of anexternal sensor assembly840 is provided inFIG. 57. In this embodiment, theradiation source882 also acts as a radiation detector so there is no need for a separate detector. In this more compact external sensor configuration, the radiation source anddetector882 transmitsbeams884 into therotating drive portion881 through or over the path in thedrive portion881. Thereflector885 reflects thebeams884 toward therotor202 and thecentrifuge bag226 to create a sampling window within thecentrifuge bag226 in which density changes may be monitored. After passing through thecentrifuge bag226 and included fluid sample, thebeams888 strike asecond reflector887 that is positioned within therotor202 to reflect thebeams888 back over the same or substantially the same path through thecentrifuge bag226 to again strike thereflector885. Thereflector885 directs thebeams888 out of thedrive portion881 and back to the radiation source anddetector882 which, in response to the impingingbeams888, transmits a feedback signal to thecontroller850 for further processing.
In one embodiment, thebeams884 enter the drivingportion881 once during every revolution of the drivingportion881. Theportion880 is preferably rotating twice for every rotation of the drivingportion881, as discussed in detail above, and hence, thesecond reflector887 is aligned to receive thebeams888 only on every other rotation of the drivingportion881. Alternatively, a pair ofreflectors887 may be positioned in therotor202 such that thebeams888 may be received and reflected back through thecentrifuge bag226 once for every rotation of the drivingportion881. In yet a further embodiment, thereflector885 andsecond reflector887 may expand partially or fully about the center axis of the centrifuge20 (with corresponding openings and/or transparent paths in the driving portion881) to provide a higher sampling rate.
According to an important feature of the invention, temperature control features are provided in an alternate embodiment of the automatedprocessing system invention900, as illustrated inFIG. 58. Providing temperature controls within theprocessing system900 can take many forms such as controlling the temperature of input fluid samples from theblood source802, monitoring and controlling the temperature of fluids in thecentrifuge bag226 to facilitate separation processes, and controlling the operating temperature of temperature sensitive components of theprocessing system900. These components include but are not limited to, red blood cells, white blood cells, plasma, platelet rich plasma or any of these components mixed with other drugs, proteins or compounds. In a preferred embodiment of the invention, a temperature control system is included in theprocessing system900 to heat components removed from thecentrifuge bag226 by the outlet pump830 to a desired temperature range. For example, when theprocessing system900 is utilized in the creation of autologous platelet gel, adispenser assembly902 is included in theprocessing system900 and includes chambers or syringes for collecting and processing platelet rich plasma drawn from thecentrifuge20. As part of the gel creation process, it is typically desirable to activate the platelets in the harvested platelet rich plasma fraction prior to the use of the gel (e.g., delivery to a patient). The temperature control system is useful in this regard for raising, and for then maintaining, the temperature of the platelets in the dispenser assembly to a predetermined activation temperature range. In one embodiment of the gel creation process, the activation temperature range is 25° C. to 50° C. and preferably 37° C. to 40° C., but it will be understood that differing temperature ranges may readily be utilized to practice the invention depending on the desired activation levels and particular products being processed or created with theprocessing system900.
Referring toFIG. 58, the temperature control system of theprocessing system900 includes atemperature controller904 that is communicatively linked to thecontroller850 withfeedback signal line906. Thecontroller850 may be utilized to initially set operating temperature ranges (e.g., an activation temperature range) and communicate these settings overfeedback signal line906 to thetemperature controller904. Alternatively, thetemperature controller904 may include input/output (I/O) devices for accepting the operating temperature ranges from an operator or these ranges may be preset as part of the initial fabrication and assembly of theprocessing system900. Thetemperature controller904 may comprise an electronic control circuit allowing linear, proportional, or other control over temperatures and heater elements and the like. In a preferred embodiment, thetemperature controller904 includes a microprocessor for calculating sensed temperatures, memory for storing temperature and control algorithms and programs, and I/O portions for receiving feedback signals from thermo sensors and for generating and transmitting control signals to various temperature control devices (e.g., resistive heat elements, fan rotors, and other devices well-known to those skilled in the heating and cooling arts).
As illustrated, atemperature sensor908 comprising one or more temperature sensing elements is provided to sense the temperature of thedispenser assembly902 and to provide a corresponding temperature feedback signal to thetemperature controller904 over signal line910 (such as an electric signal proportional to sensed temperature changes). Thetemperature sensor908 may be any temperature sensitive device useful for sensing temperature and, in response, generating a feedback signal useful by thetemperature controller904, such as a thermistor, thermocouple, and the like. In a preferred embodiment, thetemperature sensor908 is positioned within thedispenser assembly902 to be in heat transferring or heat sensing contact with the syringes or other chambers containing the separated product which is to be activated. In this manner, thetemperature controller904 is able to better monitor whether the temperature of the relevant chambers within thedispenser assembly902 is within the desired activation temperature range.
To maintain the chambers of thedispenser assembly902 within a temperature range, aheater element913 is included in the temperature control system and is selectively operable by thetemperature controller904 such as by operation of a power source based on signals received from thetemperature sensor908. Theheater element913 may comprise any number of devices useful for heating an object such as the chambers of thedispenser assembly902, such as a fluid heat exchanger with tubing in heat exchange contact with the chambers. In a preferred example, but not as a limitation, electrical resistance-type heaters comprising coils, plates, and the like are utilized as part of theheater element913. Preferably, in this embodiment, the resistive portions of theheater element913 would be formed into a shape that conforms to the shape of the exterior portion of the chambers of thedispenser assembly902 to provide efficient heat transfer but preferably also allow for insertion and removal of the chambers of thedispenser assembly902. During operation of theseparation system900, thetemperature controller904 is configured to receive an operating temperature range, to receive and process temperature feedback signals from thetemperature sensor908, and in response, to selectively operate theheater element913 to first raise the temperature of the chambers of thedispenser assembly902 to a temperature within the operating temperature range and to second maintain the sensed temperature within the operating range.
For example, a desired operating range for activating a gel or manipulating other cellular components and their reactions onto themselves or with agents may be provided as a set point temperature (or desired activation temperature) with a tolerance provided on either side of this set point temperature. Thetemperature controller904, in this example, may operate theheater element913 to raise the temperature of the chambers of thedispenser assembly902 to a temperature above the set point temperature but below the upper tolerance temperature at which point theheater element913 may be shut off by thetemperature controller904. When the temperature sensed by thetemperature sensor908 drops below the set point temperature but above the lower tolerance temperature, thetemperature controller904 operates theheater element913 to again raise the sensed temperature to above the set point temperature but below the upper tolerance temperature. In this manner, thetemperature controller904 effectively maintains the temperature of the chambers in thedispenser assembly902 within a desired activation temperature range (which, of course, may be a very small range that approximates a single set temperature). In one embodiment, the temperature controller is or operates as a proportional integral derivative (PID) temperature controller to provide enhanced temperature control with smaller peaks and abrupt changes in the temperature produced by theheater element913. Additionally, thetemperature controller904 may include visual indicators (such as LEDs) to indicate when the sensed temperature is within a set operating range and/or audio alarms to indicate when the sensed temperature is outside the set operating range.
In another embodiment, theheater element913 is configured to operate at more than one setting such that it may be operated throughout operation of theprocessing system900 and is not shut off. For example, theheater element913 may have a lower setting designed to maintain the chambers of thedispenser assembly902 at the lower end of the operating range (e.g., acceptable activation temperature range) with higher settings that provide heating that brings the chambers up to higher temperatures within the set operating range. In another embodiment, theheater element913 is configured to heat up at selectable rates (e.g., change in temperature per unit of time) to enhance the activation or other processing of separated liquids in thedispenser assembly902. This feature provides thetemperature controller904 with control over the heating rate provided by theheater element913.
As discussed previously, the invention provides features that combine to provide a compact separation system that is particularly adapted for onsite or field use in hospitals and similar environments where space is limited.FIG. 59 illustrates one preferred arrangement of thecentrifugal processing system900 ofFIG. 58 that provides a compact profile or footprint while facilitating the inclusion of a temperature control system. Anenclosure916 is included as part of the temperature control system to provide structural support and protection for the components of the temperature control system. Theenclosure916 may be fabricated from a number of structural materials, such as plastic. Theenclosure916 supports aheater housing918 that is configured to allow insertion and removal of the chambers and other elements of thedispenser assembly902. Theheater housing918 has a wall that contains the heater element913 (not shown inFIG. 59) which is connected viacontrol line914 to thetemperature controller904. The temperature sensor908 (not shown inFIG. 59) is also positioned within theheater housing918, and as discussed with reference toFIG. 58, is positioned relative to the chambers of thedispenser assembly902 to sense the temperature of the chambers, and the contained fluid, during operation of thesystem900. A temperature feedback signal is transmitted by thetemperature sensor908 overline910 totemperature controller904, which responds by selectively operating theheater element913 to maintain the temperature within theheater housing918 within a selected operating range.
Because theseparation system900 includes temperature sensitive components, such as thecontroller850, the temperature control system preferably is configured to monitor and control the temperature within theenclosure916. As illustrated, atemperature sensor920 is included to sense the ambient temperature within theenclosure916 and to transmit a feedback signal overline922 totemperature controller904. Anair inlet930, such as a louver, is provided in theenclosure916 to allow air, AIN, to be drawn into and through theenclosure916 to remove heated air and maintain the temperature within theenclosure916 at an acceptable ambient temperature. To circulate the cooling air, afan934 is provided to pull the air, AIN, into theenclosure916 and to discharge hotter air, AOUT, out of theenclosure916. Thefan934 is selectively operable by thetemperature controller904 via control signals overline938. The size or rating of thefan934 may vary in embodiments of the invention and is preferably selected based on the volume of theenclosure916, the components positioned within the enclosure916 (e.g., the quantity of heat generated by theseparation system900 components), the desired ambient temperature for theenclosure916, and other cooling design factors.
In an alternate embodiment of the present invention adispenser902, as shown inFIG. 60, is provided, for manipulating the cellular fraction which has been isolated and collected viaoutlet lumen232. In general, the present invention relates to adispenser902 which allows for a manual or automated manipulation of a two-phase method for forming anautologous platelet gel970 composition wherein all of the blood components for theplatelet gel970 are derived from a patient to whom theplatelet gel970 will be applied.
The methods of the present invention for preparing anautologous platelet gel970 composition, discussed in further detail below, are represented in the flow diagrams depicted inFIGS. 61-63. As discussed previously, the methods of the present invention begins by forming anticoagulated whole blood396 which is achieved by collecting a patient'swhole blood394 in asource container398 having an anticoagulation agent; such as sodium citrate (citrate) or heparin. Preferably, thewhole blood394 is collected and mixed with a 3.8% solution of sodium citrate (referred to herein as “citrate collection medium”) specifically in a 9:1 ratio of blood to citrate collection-medium. A 3.8% solution of sodium citrate is prepared by adding 3.8 grams of sodium citrate per 100 ml of water. While a 3.8% sodium citrate collection medium is that which is frequently used to collect and preserve blood, the person skilled in this art will recognize that the ratio of sodium citrate to whole blood could be in the range of about 10.9-12.9% mMol final concentration.
First, as discussed in detail previously and depicted inFIG. 61, plateletrich plasma260 and/or plateletpoor plasma262 are formed by centrifuging a quantity of anticoagulated whole blood396 that was previously drawn from the patient. The plateletrich plasma260 is first drawn from thecentrifuge bag226 and intocollection chamber400.Collection chamber400 is preferably a syringe, but any container that will not contact activate the collected fraction is acceptable. The plateletrich plasma260 can be pumped via outlet pump803 (FIG. 53) into acollection chamber400 or the desired fraction can be drawn directly intodispenser902.
In the preferred embodiment, depicted inFIG. 62 according toroute951, the plateletrich plasma260, incentrifuge bag226, is divided into two portions and stored invessels952 and960. The first portion is approximately ¼ to ½ of the total volume of plateletrich plasma260 and is utilized in phase-one to prepare the thrombin, while the second portion of plateletrich plasma260 is utilized in phase-twovessel960. Once the plateletrich plasma260 or alternatively the platelet poor plasma262 (shown inFIG. 61) is obtained, the preferred methods to obtain thrombin and then produce the platelet gel compositions in an expedited manner, that is, in less than three minutes, are detailed diagrammatically inroutes951 or981, shown inFIGS. 62 and 63, respectively and discussed in detail below. If, however, a longer clotting time, that is, in a range of two to eight minutes, is desirous the method to obtain the platelet gel composition of the present invention can proceed along theroutes971 and987, which are also detailed diagrammatically inFIGS. 63 and 63, respectively and discussed in detail below.
Phase-one according to the preferred embodiment (FIG. 62) begins by restoring the clot-forming process. To accomplish this, an agent (restoration agent) capable of reversing the effects of the anticoagulation agent is added back into the first portion of the plateletrich plasma260 stored invessel952. Preferably, the restoration agent can bevessel952 itself or the restoration agent is contained withinvessel952 prior to the introduction of plateletrich plasma260; however, the restoration agent may also be introduced later. It is furthermore preferable that the contact activator be a material such as but not limited toglass wool953 or silica, aluminum, diatomaceous earth, kaolin, etc., or non-wettable surfaces such as plastic, siliconized glass, etc. Chemical activators, such as kaolin, can also be used to speed up the clotting time; however, their subsequent removal would also be necessary. In the preferred embodiment, a plastic syringe is the preferred container used to collect the desired fraction. In the presently preferred embodiment of the invention, the reversal of the anticoagulant is accomplished using calcium chloride. However, any substance which is known or found to be functionally equivalent to calcium chloride, such as, calcium gluconate or calcium carbonate, in restoring the coagulation activity of citrated blood may be used in the practice of the present invention. Thus, although calcium chloride is the presently preferred calcium salt for use in the invention, any calcium salt which functions in a similar manner to calcium chloride may be used in the invention. Similarly, although many blood coagulation reactions are currently believed to require calcium ions as cofactors, any substance which is known or subsequently found to be functionally equivalent to calcium in facilitating these coagulation reactions may be used, either individually or in combination with calcium, in the practice of the present invention. If the anticoagulation agent used was heparin, then heparinase or any other suitable anticoagulant reversing compound would be used to reverse the effect of the anticoagulation agent. The concentration of the restoration agent used to reverse the anticoagulation will depend in part, upon the concentration of the anticoagulation agent in the plateletrich plasma260 and the stoichiometry of the chelating and coagulation reactions. However, the concentration of the restoration agent used to reverse the anticoagulation must be sufficient to achieve clot formation.
Upon restoration of the plateletrich plasma260 as shown inFIG. 62, aclot954 will naturally form. The resultingclot954 is then triturated by squeezing theclot954 throughglass wool953 which serves not only as a contact activator but also as a filter, thus expressingthrombin955. Alternatively, or in addition afilter958 having a large micron pore size thereby allowing the removal of clot debris and any activator or solids that are present.Filter958 is positioned at theoutlet956 ofvessel952. In the preferred embodiment, thethrombin955 is then mixed with the second portion of platelet rich plasma (PRP)260 contained withinvessel960 to form theplatelet gel composition970 of the present invention in less than three minutes and in quantities sufficient for clinical use.
Other additives can be added to the above-described process to increase the concentration of thrombin formed by the intrinsic pathway or the extrinsic pathway.
As discussed in detail above, restoring the clotting cascade function of citrated plasma by addition of calcium chloride and exposure to an activating agent such as glass wool can generate autologous thrombin. The yield of autologous thrombin by this method however, may be low due to incomplete conversion of prothrombin and the inactivation of generated thrombin by fibrin and antithrombin III. The addition of modifying-agents, such as epsilon aminocaproic acid, to the plasma may improve the yield by reducing the amount of thrombin neutralization. The greatest improvement in thrombin yield, however, will be achieved by providing a thromboplastic material upon which the necessary clotting factors will assemble to maximize the rate of prothrombin conversion. The activated platelet membrane provides such a stimulant surface and also enriches the necessary factor V activity by secreting additional factor V during platelet degranulation. The addition of exogenous lipoprotein and/or thromboplastic material to the plasma environment may also serve to maximize the thrombin generation by activation of both intrinsic and extrinsic clotting cascades. Additional amplification of autologous thrombin generation may also be attained by pretreatment of PRP and/or PPP to block or remove both antithrombin-If and fibrinogen prior to conversion of prothrombin to thrombin. Such modification may be attained by use of appropriate adsorptive agents, antibodies or precipitating reagents.
In an alternative embodiment,thrombin955 is mixed with the plateletpoor plasma262 of phase-two thereby forming the autologousplatelet gel composition972 of the present invention in less than three minutes.
A third embodiment of the present invention,route971, shown inFIG. 62, contemplates collecting the original quantity of platelet rich plasma (PRP)260 derived from the anticoagulated whole blood396 in a container, having a wettable surface, such as glass. The plateletrich plasma260 is then recalcified and theplatelet gel composition974 forms. The desiredplatelet gel composition974 will require approximately two to eight minutes to form as opposed to less than a three minute formation as was described in the preferred embodiment.
In the fourth embodiment depicted diagrammatically byroute981 inFIG. 63, the plateletpoor plasma262, rather then the plateletrich plasma260, is divided into two portions, as discussed previously in the preferred embodiment. The first portion, used in phase-one, which is approximately ¼ to ½ the original volume is stored in avessel952 having a wettable surface, then the restoration agent, preferably calcium chloride, is added directly to the plateletpoor plasma262. Surface activation of the restored plateletpoor plasma262 occurs as result of the vessel's surface and/or theglass wool953 or other surface or chemical activators and aclot962 thus forms. The resultingclot962 is triturated, as described previously, and thethrombin955 is collected.Thrombin955 is then mixed with the plateletrich plasma260 of phase-two thereby forming the plateletgel sealant composition973.
In the fifth embodiment,thrombin955 is mixed with the plateletpoor plasma262 of phase-two thereby forming theplatelet gel composition975 in less than three minutes.
The sixth embodiment followsroute987, shown inFIG. 63 wherein the original quantity of plateletpoor plasma262 is collected in a container having a wettable surface, such as glass. The plateletpoor plasma262 is then recalcified and the platelet gel composition forms.
The tensile strength of the platelet gel compositions of the present invention can be effected by the addition of calcium ions. Consequently, if a stronger bioadhesive sealant composition is desired using the methods discussed above and disclosed inroutes951 and981, inFIGS. 62 and 62, respectively, more calcium ions may be added at the time the serum is introduced into the plateletrich plasma260 or the plateletpoor plasma262. Alternatively, if the method of preparing the platelet gel compositions followsroutes971 and987, depicted inFIGS. 62 and 63, respectively, then calcium ions may be introduced directly into the plateletrich plasma260 or the plateletpoor plasma262 and theplatelet gel compositions974 and976, respectively, will form.
As discussed in further detail below, the time period necessary for the formation of the platelet gel composition of the present invention is dependent on the quantity of serum added. A 1:4, 1:2 and 3:4 ratio of serum to platelet rich plasma or platelet poor plasma results in the formation of the platelet gel composition in approximately 90, 55 and 30 seconds, respectively. Furthermore, due to the fact that thrombin is autocatalytic, it is important that the serum be used within five hours of preparation, preferably within two hours and ideally immediately. Alternatively, the serum can be chilled or frozen indefinitely.
The platelet gel compositions of this invention may be used for sealing a surgical wound by applying to the wound a suitable amount platelet rich plasma or platelet poor plasma. Moreover, due to the fact that the platelet gel compositions of the present invention have been prepared solely from blood components derived from the patient that is to receive the platelet gel there is a zero probability of introducing a new blood transmitted disease to the patient. The methods of the present invention may be further modified so that the formed platelet gel composition functions not only as a haemostatic agent, but also as an adjunct to wound healing and as a matrix for delivery of drugs and proteins with other biologic activities. For example, it is well known that fibrin glue has a great affinity to bind bone fragments which is useful in bone reconstruction, as in plastic surgery or the repair of major bone breaks. Consequently, in keeping with the autologous nature of the platelet gel composition of the present invention autologous bone from a patient can be ground or made into powder or the like, and mixed into the platelet rich plasma obtained in phase-two of the methods of the present invention. Autologous thrombin is then mixed in with the platelet rich plasma and bone fragments in an amount sufficient to allow the resulting gel to be applied to the desired locale where it congeals. Other materials that may be utilized are, but not limited to, gelatin collagen, degradable polymers, hyaluronic acid, carbohydrates and starches.
In instances where the desired platelet gel composition of the present invention is to further function as a delivery device of drugs and proteins with other biologic activities the method of the present invention may be modified as follows. Prior to adding the thrombin, obtained in phase-one, to the platelet rich plasma of phase-two a wide variety of drugs and proteins with other biologic activities may be added to the platelet rich plasma of phase-two. Examples of the agents to be added to the platelet rich plasma prior to the addition of the serum include, but are not limited to, analgesic compounds, such as Lidocaine, antibacterial compounds, including bactericidal and bacteriostatic compounds, antibiotics (e.g., adriamycin, erythromycin, gentimycin, penicillin, tobramycin), antifungal compounds, anti-inflammatories, antiparasitic compounds, antiviral compounds, anticancer compounds, such as paclitaxol enzymes, enzyme inhibitors, glycoproteins, growth factors (e.g. lymphokines, cytokines), hormones, steroids, glucocorticosteroids, immunomodulators, immunoglobulins, minerals, neuroleptics, proteins, peptides, lipoproteins, tumoricidal compounds, tumorstatic compounds, toxins and vitamins (e.g., Vitamin A, Vitamin E, Vitamin B, Vitamin C, Vitamin D, or derivatives thereof). It is also envisioned that selected fragments, portions, derivatives, or analogues of some or all of the above may be used.
A number of different medical apparatuses and testing methods exist for measuring and determining coagulation and coagulation-related activities of blood. These apparatuses and methods can be used to assist in determining the optimal formulation of activator, that is, thrombin, calcium and plasma necessary to form the platelet gel composition of the present invention. Some of the more successful techniques of evaluating blood clotting and coagulation are the plunger techniques illustrated by U.S. Pat. Nos. 4,599,219 to Cooper et al., 4,752,449 to Jackson et al., and 5,174,961 to Smith, all of which are assigned to the assignee of the present invention, and all of which are incorporated herein by reference.
Automated apparatuses employing, the plunger technique for measuring and detecting coagulation and coagulation-related activities generally comprise a plunger sensor cartridge or cartridges and a microprocessor controlled apparatus into which the cartridge is inserted. The apparatus acts upon the cartridge and the blood sample placed therein to induce and detect the coagulation-related event. The cartridge includes a plurality of test cells, each of which is defined by a tube-like member having an upper reaction chamber where a plunger assembly is located and where the analytical test is, carried out, and a reagent chamber which contains a reagent or reagents. For an activated clotting time (ACT) test, for example, the reagents include an activation reagent to activate coagulation of the blood. A plug member seals the bottom of a reagent chamber. When the test commences, the contents of the reagent chamber are forced into the reaction chamber to be mixed with the sample of fluid, usually human blood or its components. An actuator, which is a part of the apparatus, lifts the plunger assembly and lowers it, thereby reciprocating the plunger assembly through the pool of fluid in the reaction chamber. The plunger assembly descends by the force of gravity, resisted by a property of the fluid in the reaction chamber, such as its viscosity. When the property of the sample changes in a predetermined manner as a result of the onset or occurrence of a coagulation-related activity, the descent rate of the plunger assembly there through is changed. Upon a sufficient change in the descent rate, the coagulation-related activity is detected and indicated by the apparatus.
Using the methods discussed above; cartridges were assembled with serum obtained from either platelet rich plasma or platelet poor plasma, and CaCl2in the reagent chambers. Clotting time tests were performed by the automated process with either platelet rich plasma (PRP) or platelet poor plasma (PPP) dispersed into the reaction chambers of the cartridges. In the first experiment, the results of which are represented inFIG. 64, the amount of serum, the type of plasma from which the serum was derived, and the type of plasma the serum was mixed with were tested to determine the shortest clotting times. The ratios of serum to platelet rich plasma or platelet poor plasma that were studied included 1:4, 1:2, and 3:4. In the second set of experiments, the results of which are represented inFIGS. 66 and 67, the actual gel time for the platelet gel of the present invention was compared to the clotting time in the cartridge, wherein there is a 0, 36, or 60 minute delay of adding the serum from its generation. The third set of experiments, the results of which are represented inFIGS. 68 and 69, studied the effect of calcium addition on actual gel time versus clotting time in the cartridge. The final set of experiments, the results of which are represented inFIG. 65, studied the effect of adding calcium on clotting times.
Although clotting times varied among donors, comparisons of clotting times for individual donors show significant effects of the serum to plasma ratio and the calcium concentration. For all donors, the shortest clotting times occurred for the 3:4 ratio, with clotting times that were 47% shorter than those for the 1:4 ratio. Although the difference in clotting times for the 3:4 ratio and the 1:2 ratio was not statistically significant, the clotting times were consistently shorter using the 3:4 ratio for all donors. These results demonstrate that clotting times may be shortened by increasing the serum to platelet rich plasma ratio. Similarly, clotting times were significantly affected by the amount of calcium added, with the shortest clotting times obtained when no calcium was added, suggesting that the serum contained levels, of calcium that were sufficient to recalcify the citrated platelet rich plasma. Preliminary results from the scale-up experiments suggest that experimental clotting times in the cartridges correlate with actual gel times.
The invention is further illustrated by the following non-limited examples. All scientific and technical terms have the meanings as understood by one with ordinary skill in the art. The specific examples which follow illustrate the methods in which the bioadhesive sealant compositions of the present invention may be prepared in a clinical setting and are not to be construed as limiting the invention in sphere or scope. The methods may be adapted to variation in order to produce compositions embraced by this invention but not specifically disclosed. Further, variations of the methods to produce the same compositions in somewhat different fashion will be evident to one skilled in the art.
The examples herein are meant to exemplify the various aspects of carrying out the invention and are not intended to limit the invention in any way.
6 cc's of platelet rich plasma are drawn into receivingchamber961 and 3 cc's per PRP or PPP are drawn into receivingchamber957 which further contains 0.33 cc's of 10% calcium chloride and glass wool. Clotting of the contents will occur in two to eight minutes in receivingchamber957. The clot is then squeezed throughoptional filter958 and the serum, produced therefrom, is added to the platelet rich plasma contained in receivingchamber961 by either mixing or spraying the two components. The platelet rich plasma and the serum will gel within approximately three minutes.
The application of the gel using the syringe-type devices902 as described above maybe less than desirable for may applications. Consequently, in an alternate embodiment the inactive blood component and thrombin can be mixed and/or injected into a mold having a desired geometric shape. The mold may be constructed of a material having a wettable surface, such as, but not limited to plastic. In particular, platelet gel of the present invention may be used to temporarily fill, cavities such as but not limited to holes left in the gum from tooth extraction and/or holes left in tissue or bone as a result of injury or surgical procedures. The present invention provides a simpler way of introducing platelet gel for specific uses, by providing that the platelet gel be pre-shaped or molded into a beneficial shape prior to being inserted into a cavity. In the case of tooth extraction the platelet gel may be shaped so as to achieve a basic conical shape. Other shapes such as, but not limited to rods, and rectangles are contemplated by this invention. The ability to cause the gel to be more, or less, solid and thus malleable may be achieved during the activation sequence of the gel formation.
The foregoing description is considered as illustrative only of the principles of the invention. Furthermore, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and processes shown as described above. Accordingly, all suitable modifications and equivalents may be resorted to falling within the scope of the invention as defined by the claims which follow.
The foregoing description is considered as illustrative only of the principles of the invention. The words “comprise,” “comprising,” “include,” “including,” and “includes” when used in this specification and in the following claims are intended to specify the presence of one or more stated features, integers, components, or steps, but they do not preclude the presence or addition of one or more other features, integers, components, steps, or groups thereof. Furthermore, since a number of modifications and changes will readily will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and process shown described above. Accordingly, all suitable modifications and equivalents may be resorted to falling within the scope of the invention as defined by the claims which follow.
