INCREASED YIELD CONTINUOUS FLOW BLOOD COMPONENT COLLECTION SYSTEMS
FIELD OF THE INVENTION:
This application generally relates to systems and methods which enable the collection and separation of whole blood into its therapeutic components. This application also generally relates to whole blood collection and separation systems and methods which enable the storage of whole blood and its various therapeutic components for the maximum allowable periods. This application also generally relates to continuous flow extracorporeal blood processing systems and methods.
BACKGROUND AND OBJECTS OF THE INVENTION;
Instead of routinely providing infusions of whole blood to a patient, the present medical concensus is that care of a patient is improved by providing only the therapeutic components of whole blood which are required to treat the specific disease. This procedure is generally referred to as blood component therapy.
Because of the acceptance of blood component therapy by the medical community, the demand for therapeutic components of whole blood has been ever-increasing. Likewise, the demand for safe and effective systems and methods for collecting, separating, and storing the therapeutic components of whole blood has grown accordingly.
For example, the use of human platelets to treat thrombocytopenia has dramatically increased over the past ten years. The use of fresh frozen plasma, which contains virtually all of the blood's clotting factors, in the treatment of patients with diseased livers is also widespread. There are numerous other plasma-based fractions, such as albumin, protein fraction, gamma globulin, and AHF (Clotting Factor VIII), all of which have recognized specific therapeutic purposes. Likewise, red blood cells are commonly used to treat chronic anemia.
One desirable feature for a blood collection and separation system and method is its capability to maximize, to the greatest extent possible, the yield of clinically proven blood components during a single collection procedure. The importance of this feature
stems in large part from the traditionally limited number of donors who regularly provide red cells and/or plasma-based components of whole blood.
The importance of this feature also stems from the periodic nature of blood collection procedures themselves. In the United States, for example, a collection from an individual donor of one unit of whole blood (approximately 450 milliliters) for separation into its various components can be undertaken only once every 8 weeks if the donor's red cells are retained for storage*. If the red cells are returned to the donor and only the plasma-based fractions are retained (such as during plasmapheresis or plateletpheresis) , the collection procedure can usually be repeated more often, i.e., twice in a seven day period. However, even then, in the United States, there"are limits placed upon the total plasma volume which can be collected from a donor during a single procedure. Presently, the maximum allowable plasma volume limit per procedure (exclusive of anticoagulant) is approximately 720 milliliters of plasma for donors weighing less than 175 pounds and approximately 875 milliliters of plasma for donors weighing 175 pounds or more. The importance of this feature also stems from the relatively large doses of certain components required to achieve the desired therapeutic effect. For example, a single therapeutic dose of platelets is typically approximately 35 to 45 x 10 platelets. This is about eight times the number of
platelets which can be collected from one unit of whole blood. In other words, the equivalent of eight units of whole blood is required to meet the needs of a single patient in need of platelets. Systems which serve to maximize the component yield for each procedure can help to offset these factors which together limit the supply of blood available for therapeutic purposes.
Another, although very closely related, desirable feature for a blood collection and separation system and method is its ability to be used in combination with a "continuous flow" extracorporeal blood processing procedure. In such a procedure, whole blood from a donor is continuously circulated through the separation system, with a portion of the components being collected (or "harvested"), and the remainder being returned to the donor. Blood deprivation to the donor at any given moment during the procedure is thus minimized. As a result, significantly larger total volumes of whole blood can be processed in a continuous flow procedure than in a single unit batch collection procedure. This results in larger yields of plasma-based fractions. For example, in a single unit batch collection procedure, approximately 5 x 10 platelets can be harvested; in a continuous flow procedure, upwards to 60 x 10 platelets can be collected. The advantage of utilizing a continuous flow system is apparent. Another desirable feature for a blood collection and separation system and method is its capability of yielding components which are suited
for storage for prolonged periods. This feature, which also helps to offset the limited supply of available whole blood, is closely related to the degree of sterility that given blood collection system can assure.
For example, in the United States, whole blood and components which are collected and processed in a nonsterile, or "open", system, whether it be a single unit or a continuous flow procedure, must be transfused within twenty-four (24) hours of collection. On the other hand, in" the United States, whole blood and red cells which are collected in a sterile, or "closed", system, whether a single unit or continuous flow procedure, may be stored for upwards to thirty-five days, depending upon the type of anticoagulant and storage medium used. Similarly, in the United States, platelets which are collected in a sterile, or "closed", system may be stored for upwards to five days, and possibly longer, depending upon the ability of the storage container to maintain proper storage conditions.
In the United States, Federal Regulations [Title 21 C.F.R. §640.16(b)] define a "closed" blood collection system as one in which the initially sterile blood collection and transfer containers are integrally attached to each other and not open to communication with the atmosphere. Furthermore, to remain a "closed" blood collection system in the United States, the system cannot be "entered" in a non-sterile fashion after blood collection. By United States standards, an entry into a blood collection system which presents the probability of
non-sterility which exceeds one in a million (i.e., greater than 10- ) constitutes a "non-sterile" entry. A non-sterile entry "opens" a heretofore "closed" system and dictates the significantly shortened storage periods for the blood and components collected and processed within the system.
With the foregoing considerations in mind, one of the principal objects of this invention is to provide a blood component collection system and method which maximizes, to the greatest extent possible, the yield of blood components obtained during a collection procedure in a manner which also assures the maximum allowable storage period for each of the components collected. Another one of the principal objects of this invention is to provide the blood component collection system as just described which is capable of being used in the context of a continuous flow procedure. * in addition to the foregoing considerations, yet another desirable feature for a blood collection and separation system and method is that it constitutes a compact and easily handled system which can be efficiently manufactured, stored, and utilized by the operator.
With this in mind, it is another one of the principal objects of this invention is to provide a blood component collection system which is formed of two or more initially separate, closed subsystems
which are compact and easily handled and which can be sequentially joined together without compromising the sterile integrity of any of the subsystems or the formed system as a whole.
SUMMARY OF THE INVENTION;
To achieve these and other objects, the invention provides an increased yield blood component collection system which maximizes, to the greatest extent possible, the yield of blood components obtained during a continuous flow extracorporeal blood collection procedure in a manner which also assures the maximum permissible storage period for each of the components collected.
The system which embodies the features of the invention comprises first and second centrifugation containers, each of which is suited for placement within the centrifugal separation chamber of an extracorporeal blood separation device. The system further includes first and second transfer containers in which some of the components separated within the centrifugal containers can be collected for storage.
The system also includes conduit means for establishing a plurality of fluid paths which are closed from communication with the atmosphere and which integrally interconnect the heretofore described parts of the system.
More particularly, the conduit means includes first branch means operative for introducing whole blood from a donor into the first centrifugation container for separation into first
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and second components (for example, red cells and platelet-rich plasma). The conduit means also includes second branch means operative for returning the first component (e.g., the red cells) from the first centrifugation container to the donor.
The conduit means further includes third branch means communicating with the first centrifugation container and the second centrifugation container. The second component (e.g., the platelet-rich plasma) is transferred through the third branch means into the second centrifugation container.. There, the second component is further separated into third and fourth components (for example, platelets and platelet-poor plasma).
The conduit means additionally includes fourth branch means communicating with the second centrifugation container and the first transfer container. The fourth branch means is operative for transferring the third component (e.g., the platelets) into the first transfer container. Fifth branch means also communicates with the second centrifugation container and the second transfer container for transferring the fourth component (e.g., the platelet-poor plasma) into the second transfer container. Sixth branch means is also provided for diverting the fourth component away from the second transfer container for return to the donor. In one embodiment, the system further includes a third transfer container. In this arrangement, the conduit means includes seventh branch means communicating with the second branch
means and the third transfer container for diverting the first component (e.g., the red cells) from the donor and into the third transfer container.
In one embodiment, the system also includes a source of sterile anticoagulant solution and a source of sterile saline solution. In this embodiment, the conduit means includes additional branch means for introducing these sterile solutions into the system. The system enables the collection, during a single continuous flow procedure, of upwards to about 60 x 10 platelets (suspended in about 200 milliliters of plasma); upwards*to about 500 milliliters of platelet-poor plasma; and (optionally) upwards to about 250 milliliters of packed red cells. The total volume amount which can be collected by the* system during a given procedure will ultimately depend upon the physiology of the donor and the maximum allowable total volumes permitted by governing regulations.
Because the system, once sterilized, constitutes a closed system, all of the components which are collected are suited for the maximum allowable storage periods. To further enhance the storage of the collected components, in one embodiment, each transfer container is imparted with a predetermined physical characteristic which is beneficial to long-term storage of the blood component therein transferred.
For example, the transfer container which receives the platelets preferably has a physical characteristic of improved gas transmission
characteristics which has a demonstrated beneficial effect upon platelet viability. Likewise, the transfer container which receives the platelet-poor plasma is preferably made of material having relatively high low-temperature strength to facilitate freezing of the plasma for prolonged storage periods. Similarly, the transfer container which receives the red cells is preferably made of a material known to suppress hemolysis in red cells during long term storage. Alternately, this container includes a red dell storage and nutrient solution known to achieve the same result.
In one embodiment of the system, all or some of the containers associated with the system comprise physically separate entities which can be selectively joined to form the system without comprising the sterile integrity of any of the containers or the formed system as a whole.
Other features and advantages of the invention will be pointed out in, or will be apparent from, the specification and claims, as will obvious modification of the embodiments shown in the drawings.
DESCRIPTION OF THE DRAWINGS;
Fig. 1 is a functional diagrammatic view of an increased yield blood component collection system which embodies various of the features of the invention;
Fig. 2 is a perspective view of a continuous flow extracorporeal blood processing device, with portions broken away and in section, with which the collection system shown in Fig. 1 can be associated;
Fig. 3 is a plan view of one embodiment of the increased yield collection system shown in Fig. 1 in combination with the processing device shown in Fig. 2; Fig. 4 is a plan view, partially in functional diagrammatic form, of another embodiment of the increased yield collection system shown in Fig. 1;
Fig. 5 is an enlarged view of a portion of the increased yield collection system shown in Fig. 4;
Fig. 6 is a further erilarged view, with portions broken away and in section, of a portion of the system shown in Fig. 5, showing the connector means associated with the system in an uncoupled relationship;
Fig. 7 is an enlarged view, with portions broken away and in section, of the connector means shown in Fig. 6 in a coupled relationship and being exposed to a radiant energy-induced melting apparatus to open a fluid path therethrough; and
Fig. 8 is an enlarged view, with portions broken away and in section, of the connector means shown in Fig. 7 after the fluid path has been opened therethrough.
Before explaining the embodiments of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components as set forth in the following description or as illustrated in the accompanying drawings. The invention is capable of other embodiment and of being
practiced or carried out in various ways. Furthermore, it is to be understood that the phraseology and terminology employed herein is for the purpose of description and should not be regarded as limiting.
DESCRIPTION OF THE PREFERRED EMBODIMENT;
An increased yield blood component collection system 10 is shown in Fig. 1. The system 10 is particularly designed for use in combination with an extracorporeal blood processing device 12 having a centrifugal separation chamber 14, both of which are shown schematically in Fig. 1.
The system 10 includes first and second containers, respectively 20 and 22. Each of the containers 20 and 22 is made of a material suited to withstand high speed centrifugation. Each container 20 and 22 is thus suited for placement within the separation chamber 14 of the device 12.
To retain certain blood components for storage, the system 10 includes two and, optionally, three transfer containers, respectively 26, 28, and 30.
To establish fluid communication between the various elements of the system 10, the system 10 includes conduit means 34. The conduit means 34 establishes a plurality of fluid paths, each of which is closed from communication with the atmosphere. Because of this, the system 10, once sterilized, constitutes a closed system as measured by applicable United States standards.
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More particularly, and still referring principally to Fig. 1, the conduit means 34 includes first branch means 36 which communicates at one end with the first centrifugal container 20. The first branch means 36 communicates at its other end with a phlebotomy needle 16. The first branch means 36 is thus operative for introducing whole blood drawn from the donor 18 into the first centrifugation container 20. The whole blood which is introduced into the container 20 is subjected to a, centrifugal force field developed within the chamber 14. As will be described in greater detail later herein, because of differences in densities, first and second components of the whole blood separate and congregate within the container 20 in different zones radially spaced from the rotational axis 24 of the chamber 14,
The conduit means 34 further includes second branch means 38 which communicates at one end with the first centrifugal container 20. The second branch means 38 communicates at its other end with another phlebotomy needle 32. The second branch means 38 is operative for returning to the donor a selected one of the components which has been separated within the first container 20.
Each phlebotomy needle 16 and 32 may be integrally connected with the associated branch conduit means 36 and 38 and be normally sealed from communication from the atmosphere by a conventional needle cover or sheath (not shown) which is removed at time of venipuncture.
Alternately, each branch conduit means 36 and 38 can include a convention needle adaptor (such as those provided in FENWAL® Blood Recipient Sets, sold by Fenwal Laboratories, a division of Travenol
5 Laboratories, Inc., Deerfield, Illinois). The needle adaptor receives the needles 36 and 38 prior to venipuncture.
While individual phlebotomy needles 16 and
32 are shown in Fig. 1, it should be appreciated that
10 the first and second branch means 36 and 38 could each communicate with a single, multiple lumen needle of conventional construction (not shown) .
! The conduit means 34 also includes third
! branch means 40 which extends between the first
15 centrifugation container 20 and the second centrifugation container 22. The third branch means t
I 40 is operative for transferring the remaining i j separated component from the first centrifugation container 20 into the second centrifugation container i 20 22. In the second container 22, this component is
! further separated as a result of centrifugation into a third component and a fourth component.
The conduit means 34 includes fourth branch means 42 which extends between the second centrifugal
25 container 22 and the first transfer container 26.
The fourth branch means 42 is operative for transferring the third component from the second centrifugal container 22 into the first transfer container 26.
30 Similarily, fifth branch means 44 is provided between the second centrifugation container
22 and the second transfer container 28. The fifth
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branch means 44 is operative for transferring the fourth component from the second container 22 into the second transfer container 28.
The conduit means 34 also includes sixth branch means 46 which extends between the fifth branch means 44 and the second branch means 38. The sixth branch means 46 is operative for diverting all or a portion of the fourth component carried by the fourth branch means 44 away from the second transfer container 28 for return to the donor, when desired.
The system' 10 can optionally include a third transfer container 30. In this arrangement, the conduit means further includes seventh branch means 48 which extends between the second branch means 38 and the third transfer container 30. The seventh branch means 48 is operative for diverting a portion of the first component carried by the second branch means 38 away from the donor and into the third transfer container 30, if retention of this component is desired.
In the illustrated and preferred embodiment, the system 10 also includes a source 50 of sterile anticoagulant solution and a source 52 of sterile saline solution. in this arrangement, the conduit means 34 includes eighth branch means 54 which is operative for introducing the anticoagulant solution into the system to prevent the donor's blood from clotting during the course of the procedure. in this arrangement, the conduit means 34 further includes ninth branch means, designated 56a and 56b in Fig. 1, which is operative for introducing
saline into the system 10 to purge air from the system 10 prior to the procedure and to wash components from the system 10 after the procedure. In the particular preferred arrangement shown in Fig. 1, the saline enters the system 10 via the branch conduit means 56a, which communicates with the first branch means 36. The saline is ultimately returned, or vented, to the saline source 52 via the branch conduit means 56b, which communicates with the second branch means 38.
In an alternate arrangement (not shown), the return branch conduit means 56b could be eliminated, and the priming volume of saline could be vented directly through the return phlebotomy needle 32. in another alternate arrangement, the return branch conduit means 56b could be eliminated, and a saline collection container 53 (shown in phantom lines in Fig. 1) could communicate with the second branch means 38 via an auxiliary branch conduit means 57 (also shown in phantom lines in Fig. 1). The priming volume of saline would thus be collected in the container 53.
To control and direct the flow of whole blood and its components in the system 10, valve means 58 is provided inline with the first; second; fourth; fifth; sixth; seventh; eighth; ninth; and (in the one alternate embodiment) the auxiliary branch means, respectively 36; 38; 42; 44; 46; 48; 54; 56a and b; and 57. The valve means 58 can be variously constructed. For example, the valve means 58 can
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take the form of a manually operable clamping mechanism, such as a roller clamp or a hemostat. Alternately, all or some of the valve means 58 can be electrically actuated valves interconnected with the control circuitry of the processing device 12.
The system 10 as heretofore described is capable of collecting the maximum allowable volumes of up to three therapeutic components. Furthermore, and significantly, because the system 10 as a whole constitutes, after sterilization, a closed system (as judged by applicable standards"in the United States), the maximum permissable storage time is obtained for each of the components collected.
To further enhance the storage of the components collected by the system 10, at least a portion of each of the transfer containers 26, 28, and 30 is purposely imparted with a predetermined physical characteristic which is beneficial to the intended storage function of the container 26, 28, and 30. This aspect will be described in greater detail later herein.
To effectively use the system 10 for its intended increased yield purposes, the processing device 12 is one which is capable of processing blood in a continuous flow through the system 10 without compromising the closed, sterile integrity of the system 10. An example of such a device is found in Cullis et al, U.S. Patents 4,146,172 and 4,185,629. An example of a commercially available device with which the system 10 is particularly well-suited for
use is the CS-3000® Blood Cell Separator, which is manufactured and sold by Fenwal Laboratories. This particular processing device 12 is generally shown in Fig. 2. 5 The system 10 shown in Fig. 3 is adapted for a close operative interface with the device 12 shown in Fig. 2 and is constructed generally along the lines disclosed in co-pending DeVries, U.S. Patent Application 100,975 (filed December 6, 1979), ° entitled MONITOR AND FLUID CIRCUIT ASSEMBLY, which is a continuation of DeVries,^ U.S. Patent Application 843,223 (filed October 18, 1977), now abandoned.
In the system 10' shown in Fig. 3, the conduit means 34 takes the form of a plurality of 5 flexible branch conduits, preferably made of a plasticized polyvinyl chloride material. These conduits will be identified by the same reference numerals as the corresponding branch conduit means in Fig. 1. As best shown in Fig. 3, the branches of the conduit means 34 are supported by a compact housing 60. Means 62 is provided on the sidewalls 64 of the housing 60 for supporting certain branches of the conduit means 34 within the confines of the housing 60, while supporting selected ones of these branches in predetermined looped, or arcuate, configurations which are outwardly bowed from one of the sidewalls 64 and which are resiliently biased toward an upright, freestanding position generally perpendicular to the one sidewall 64. As can be seen
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in Figs. 2 and 3, this looped configuration enables the desired close operative interface between the system 10 and the peristaltic pump rotors 66 and 68 associated with the processing device 12. Also in this arrangement, the housing 60 includes various monitoring devices 76, 78, 90, 92, . and 96 (see, in particular, Fig. 3) which are adapted to operatively interface with associated sensing mechanisms on the processing device 12 to monitor the flow of components through the system 10.
Furthermore, in the illustrated arrangement, the portions of the conduit means 34 which communicate with the first and second centrifugation containers 20 and 22 are combined in an umbilicus 70. According to the principles discussed in Adams, U.S. Patent RE 29,738, this umbilicus 70 is rotated at a speed o'ne half the speed of the containers 20 and 22. Twisting of the umbilicus 70 between portions of the systems 10 located inside and outside the chamber 14 is thereby avoided, and fluid communication through the umbilicus 70 is continuously maintained without the use of rotating seals. The sterile closed integrity of the system 10 is thus not compromised. it should be appreciated that the system 10 can be readily adapted for use with a device employing a rotating seal arrangement or the like, • provided that the rotating seal arrangement or its equivalent does not compromise the sterile integrity of the system 10.
Reference is now made to the particular arrangement of the conduit means 34 in the embodiment shown in Figs. 2 and 3.
The first branch conduit 36 includes an adaptor 17 which operatively connects with the inlet phlebotomy needle 1.6. The conduit 36 extends into and through the housing 60, and thence through the umbilicus 70. The conduit 36 is integrally connected to an inlet port 72 on the first centrifugation container 20 via an inline air trap 74.
A portion 37 of the first branch conduit 36 extends outwardly of the housing 60 in the freestanding looped configuration heretofore described. This enables the desired operative interface with only the pump 66 carried by the device 12. Operation of this pump 66 introduces whole blood drawn from the donor into the first centrifugation container 20.
As can be seen in Fig. 3, within the housing 60, the first branch conduit 36 flows through an occluded vein sensor 76. The sensor 76 detects an interruption or restriction of blood flow from the donor, such as may occur as a result of a collapsed vein, a blood clot, or a crimp in the conduit 36. Within the housing 60, the first branch conduit 36 also flows through a blocked line sensor 78. The sensor 78 detects a blockage caused by either a crimp or air in the conduit 36.
Both sensors 76 and 78 cooperate with sensing circuitry (not shown) carried by the device
12 to sound alarms and shut down the device 12 should detection of the undesirable conditions occur.
The first centrifugation container 20 includes a first outlet port 80 at the center thereof. This port 80 communicates with a zone 82 in which platelet-rich plasma of the donor's whole blood will congregate during centrifugation of the first container 20 within the chamber 14.
The container 20 also includes diametrically spaced second and third outlet ports 84 and 86. These ports 84 and 86 communicate with a zone 88 in which red blood cells of the donor's whole blood congregate during centrifugation.
The second branch conduit 38 is integrally connected with each of the second and third outlet ports 84 and 86 of the first container 20. The second branch conduit 38 extends through the umbilicus 70, into and through the housing 60, and thence to the return phlebotomy needle 32. Like the first branch conduit 36, the second branch conduit 38 includes an adaptor 33 which receives the needle 32. As can be seen in Fig. 3, within the housing
60, the second branch conduit 38 flows through a return line sensor 90 and a bubble trap 92.
The return line sensor 90 senses both positive and negative pressure alarm conditions. A high positive pressure indicates an obstruction in the branch conduit 38 or needle 32. A negative pressure indicates a leak.
The bubble trap 92 senses the presence of air bubbles.
Both the return line sensor 90 and bubble trap 92 cooperated with sensing circuitry (not shown) carried by the device 12 to sound alarms and shut down the device 12 should detection of the undesirable conditions occur.
The second branch conduit 38 is thus operative for carrying red cells from the zone 88 of the first container 20 back to the donor.
The third branch conduit 40 is integrally connected with the first outlet port 80 of the first centrifugation container 20. The conduit 40 extends through the umbilicus 70, into and through the housing 60, and thence ba'ck through the umbilicus 70 to an inlet port 94 of the second centrifugation container 22.
A portion 41 of the third branch conduit 40 extends in the heretofore described looped freestanding configuration. This portion 41 is spaced a predetermined distance from the looped portion 37 of the first branch conduit 36. The looped portion 41 of the third branch conduit 40 thus fits over only the pump 68 carried by the device 12.
The third branch conduit 40 is thus operative for carrying platelet-rich plasma from the zone 82 of the first container 20 info the second container 22 in response to operation of the pump 68.
Within the housing 60, the third branch conduit 40 flows through an interface detector 96. The detector 96 senses the presence of red blood cells in the third branch conduit 40. If red cells appear, this indicates that the interface 87 (see Fig. 3) between the red cells and platelet-rich
plasma in the first container 20 has been reached. This, in turn, indicates that all of the platelet-rich plasma has been removed from the container 20. As is shown in Fig. 3, during centrifugation of the second collection container 22 within the chamber 14, the platelets which are carried in the platelet-rich plasma separate and congregate in a zone 98 in the bottom region of the container 22. The remaining component, called platelet-poor, or fresh, plasma, congregates in a zone 100 in the upper region of the container 22. A port 102 communicates with the upper zone 100 of 'the second collection container 22. In this arrangement, the fourth branch conduit 42 is integrally connected with the port 102 of the second centrifugal container 22. The conduit 42 extends, via the umbilicus 70, to an inlet port 104 on the first transfer container 26, to which the conduit 42 is integrally connected.
The fifth branch conduit 44 extends in common with the fourth branch conduit 42 from the outlet port 102 of the second container 22 and through the umbilicus 70. For this reason, the common extension of the conduit is identified by the numerals 42/44 in Fig. 3. The fifth branch conduit 44 then diverges from the fourth branch conduit 42 to integrally connect with an inlet port 106 on the second transfer container 28. By virtue of this arrangement, after the desired volume of platelet-poor plasma has been transferred, via the fifth branch conduit 44 into the
second transfer container 28, the remaining platelets (suspended in plasma) can be transferred from the bottom zone 98 of the second centrifugation container 22 through the fourth branch conduit 42 into the first transfer container 26.
The sixth branch conduit 46 integrally joins the fifth branch passage 44. The sixth branch conduit 46 extends from this junction into the housing 60, where it joins the heretofore described second branch conduit 38 upstream of the return line sensor 90 and bubble trap 92.
The sixth branch conduit 46 therefore serves, when desired, to divert the collection of platelet-poor plasma away from the second transfer container 28 to the return phlebotomy needle 32, via the return line sensor 90 and bubble trap 92. During the return to the donor, the platelet-poor plasma will mix with the red cells which are being returned via the second branch conduit 38. The source 50 of anticoagulant solution includes a bag 108 made of a plasticized polyvinyl chloride material or the like which contains the sterile anticoagulant. A suitable overwrap 110 is provided to prevent evaporation to the saline from the bag 108 during storage.
The eighth branch conduit 54 is integrally connected with the bag 108 and extends (via a drip chamber 112) into and through the housing 60 and connects with the inlet phlebotomy needle 17. As can be best seen in Fig. 3, a portion 55 of the eighth branch conduit 54 is looped concentrically with the looped portion 37 of the
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first branch conduit 36 for joint operative interface with the pump 66. By varying the interior diameter of the eighth branch conduit portion 55 relative to the interior diameter of the first branch conduit portion 37, the desired fluid flow ratios can be achieved.
The source 52 of sterile saline likewise includes a bag 114 having a suitable overwrap 116. The ninth branch conduit 56a and 56b is integrally connected with the bag 114. The outlet portion 56a of the ninth branch conduit proceeds via a drip chamber 118 to join the conduit 36 upstream of the occluded vein sensor 76, and "thus communicate with the inlet phlebotomy needle 16. The return portion 56b proceeds via a drip chamber 120 to join the bubble trap 92.
As before explained, saline enters the system 10 via the portion 56a and is returned, or vented, to the bag 114 via the portion 56b. The integral connection between the overwrapped anticoagulant and saline bags 108 and 114 and their associated branch conduits may be variously made. • In the illustrated embodiment, a port block assembly 122 is used, such as the one described in Boggs et el, U.S. Patent Application Serial No. 282,894, filed July 13, 1981.
The seventh branch conduit 48 is integrally ■connected with a port 107 of the third transfer container 30 and the second branch conduit 38 upstream of the return phlebotomy needle 33.
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The desired fluid flow distribution through the first, second, fourth, fifth, sixth, eighth, and ninth branch conduits (respectively, 36; 38; 42; 44; 46; 54; and 56a and b) is controlled by motor-driven clamps 124 associated with and controlled by the device 12 in sequence with the desired separation procedure. Additional external, manually operated roller clamps 126 are also provided at the locations shown in.Fig. 3. In an alternate arrangement, the roller clamps 126 could replace all or .some of the motor-driven clamps 124. r
It can be seen that, by coordinating the clamping arrangement, the desired fluid flow patterns through the system 10 can be established. More particularly, after the system 10 shown in Fig. 3 has been suitable primed with saline from the bag 114, the operator can establish a fluid flow pattern to collect whole blood from the donor (via the first branch conduit 36) in the first centrifugation container 20. During centrifugation of the container 20, platelet-rich plasma separates from the red cells in the first centrifugal container 20. The platelet-rich plasma can be transferred (via the third branch conduit 40) from the zone 82 into the second centrifugation container 22. At the same time, the fluid flow pattern can enable the red cells in the zone.88 to be returned to the donor via the second branch conduit 38.
As centrifugation continues, the platelets can be collected in the bottom zone 98 of the second centrifugation container 22. Platelet-poor plasma collects in the upper zone 100 and can be returned to
the donor via the fluid path established collectively by the fourth, sixth, and second branch conduits 42, 46, and 38.
When the desired concentration of platelets has collected in the bottom zone 98 of the second container 22 (approximately 30 x 10 to 60 x 10 platelets in approximately 200 milliliters of plasma), the operator can change the fluid flow pattern to collect platelet-poor plasma in the second transfer container 28, up to the allowable maximum volume (i.e., 500 milliliters', if approximately 100 to 200 milliliters of platelet concentration volume are collected) .
If desired, the fluid flow pattern can be changed so that approximately 200 to 250 milliliters of red cells can also be diverted at this time via the seventh branch conduit 48 into the third transfer container 30.
The total volume amount of components which can be collected in the system 10 during a given procedure will depend upon the physiology of the donor and the maximum allowable total volumes permitted by governing regulations.
After the platelet-poor plasma has been collected in the second transfer container 28, the platelet concentration which remains in the second centrifugal container 22 can then be manually expressed or otherwise pumped into the first transfer container 26.
To withstand the centrifugal forces developed in the chamber 14, the first and second centrifugation containers 20 and 22 are preferably made of a rugged plasticized polyvinyl chloride material.
To maximize the allowable storage time available, the first transfer container 26, into which platelet concentrate is transferred during the procedure, preferably has a gas transfer characteristic beneficial to prolonged platelet storage. More particularly, the first transfer container 26 would preferably have a gas transfer characteristic which excee'ds that of polyvinyl chloride plasticized with di-2-ethylhexylphthalate (DEHP).
For example, the first transfer container 26 can include a polyolefin-type container which is disclosed in Gajewski et al, U.S. Patent 4,140,162, or a polyvinyl chloride container which has been plasticized with tri-2-ethylhexyl trimellitate
(TEHTM), as disclosed in Warner et al, U.S. Patent 4,280,497.
Alternately, or in addition, the second transfer container 28 can include a platelet storage media which is suited for maintaining platelet viability during storage.
Likewise, the second transfer container 28, into which platelet-poor plasma is transferred during the procedure, is preferably made of a material having a relatively high low-temperature strength to withstand freezing of the platelet-poor plasma during storage.
Candidate materials for this purpose include various polyolefin materials, such as low density polyethylene and copolymers of polyethylene and polypropylene, including those containing a major amount of polypropylene.
To enhance the storage of the red cells which may be collected in the third transfer container 30, the third transfer container 30 is preferably made of a material which is known to suppress hemolysis in red cells during storage, such as polyvinyl chloride plasticized with DEHP.
Alternately, or in addition, the transfer container 30 can include an isotonic red cell storage solution which is suited for suppressing hemolysis during storage. Such a solution could include ingredients such as saline, adenine, mannitol, and glucose, such as the solution disclosed in Grode et al, U.S. Patent 4,267,269, or in Grode et al, U.S. Patent Application No. , filed May 11, 1982) and entitled RED CELL STORAGE SOLUTION AND METHOD.
Use of the system 10 permits, during a single continuous-flow procedure, the collection of the maximum allowable amounts of virtually all of the therapeutic plasma-based components, and (optionally) a unit of red cells. Because the system 10 comprises a closed system as judged by United States standards, all of the collected components are suited for storage for the maximum allowable period.
If the operator does not collect the optional unit of red cells, the above-described procedure can be repeated generally twice a week. If the red cells are collected, the procedure can be repeated generally once every eight weeks.
Attention is now directed to the blood collection system 11 shown in Fig. 4. This system 11 shares many of the same features associated with the system 10 shown in Fig. 3. Common components are assigned the same reference numerals as in Fig. 3.
Like the system 10 shown in Fig. 3, the system 11 includes the first and second centrifugation containers 20 and 22, as well as the first, second, and third transfer containers 26, 28, and 30. As in the system 10, all or some of the containers 26, 28, and 30 can be imparted with characteristics beneficial to their storage functions. Conduit means 34 also serves to interconnect the various elements of the system 11 in a manner which closes the system 11 from communication with the atmosphere.
The system 11, like the system 10, is adapted for close operative interface with the device 12 shown in Fig. 2. Unlike the system 10 shown in Fig. 3, however, in which the containers 26, 28, 30, 108, and 114 are all integrally connected to the system 10, in Fig. 4, all or, as desired, some of the transfer containers 26, 28, and 30 and saline and anticoagulant containers 108 and 114 can constitute normally physically separate entities from the rest of the system 11.
In this arrangement, each physically separate container 26, 28, 30, 108, and 114 preferably includes a tear-away protective overwrap 127 which is removed at the time of use. The overwrap 127 also preferably prevents evaporation of the fluids in the saline and anticoagulant containers 108 and 114 during storage.
In this arrangement, the system 11 further includes means 128 for selectively establishing a fluid path between each of the normally separate containers and the remainder of the system 10 in a manner which does not compromise the sterile closed integrity of the containers or of the system as a whole. More particularly, the means 128 includes normally closed first and second connector means 130 and 132. The first connector means 130 communicates with each of the normally separate containers 26, 28, 39, 108, and 114 and is carried within the confines of the tear-away overwrap 127 prior to use. The second connector means 132 communicates with each of the corresponding branch conduits, respectively 42, 44, 48, 54, and 54a and b.
As can best be seen in Figs. 5 through 8, each connector means 130 and 132 includes means 134 for selectively mechanically coupling the associated pairs of the first and second connector means 130 and ■ 132 together with a portion 136 of each in facing contact. The facing portions 136 include means 138 operative for melting to form a fluid path through the joined pairs of the connector means 130 and 132, thereby opening fluid communication between the
container and the associated branch conduit, but only in response to exposure to an energy source efficient in itself to effectively sterilize the means 138 as they melt. This constitutes an active sterilization
5 step which occurs simultaneously with the formation of the fluid path.
Furthermore, during the act of melting, the means 138 are preferably operative for fusing together to form a hermetic seal about the periphery
10 of the fluid path. The resulting connection is thus internally sterile and closed from communication with the atmosphere. i The connector means 130 and 132 may be j
! variously constructed and employ different means of
J 15 operation. However, to meet the desired increased-yield objectives of the system 10, the j connector means 130 and 132 each must meet certain
! operative requirements.
1 More particularly, each connector means 130 i 20 and 132 must (1) normally close the associated j portion of the system 10 from communication with the atmosphere; (2) be opened only in conjunction with an active sterilization step which serves to sterilize the regions adjacent to the fluid path as the fluid 25 path is formed; and (3) be capable of hermetically sealing the fluid path at the time it is formed. It has been determined that the sterile connector generally described in Granzow et al U.S.
Patents 4,157,723 and 4,265,280 meets all of the 30 above criteria and, for this reason, such a connector is shown in the illustrated embodiment.
The construction and operation of such a connector can be best seen in Figs. 5 through 8. More particularly, each connector means 130 and 132 includes a housing 140 which defines a hollow interior 142 which communicates with its associated part of the system 10. The heretofore described meltable means 138 associated with the facing portions 136 of the connector means 130 or 132 takes the form of meltable wall means, each of which normally seals or closes the associated interior 142 from communication with the atmospher .
The housing 140 further includes a tubular conduit portion 144 which co_nmunicates with the interior 142 and which serves to interconnect the first connector means 130 with the end of a tubing 146 integrally attached to the associated container and the second connector means 132 with the end of the associated branch conduit.
While the connector means 130 and 132 may be variously attached to the end of the tubing 146 or with the branch conduits, in the illustrated embodiment, a hermetic, friction fit between the tubular conduit portion 144 is envisioned. An elastic band 147, such as made from a latex material, preferably encircles the outer periphery of the junction to assure a fluid tight, hermetic fit between the tubular portion 144 and the respective tubings 146 or branch conduits.
To normally prevent fluid flow communication with the interior 142 of the connector means 130 in this arrangement, an inline valve member 148 (shown in phantom lines in Fig. 5) may be provided. Such an
arrangement is particularly desirable in association with the fluid-filled anticoagulant and saline containers 108 and 114.
While the valve member 148 may be variously constructed, in the illustrated embodiment, it takes the form of an inline frangible valve member 148, such as one disclosed in Bayham et al, U.S. Patents No. 4,181,140 and 4,294,247.
Alternately, the frangible valve member 148 can form an integral part of the connector housing 140, as is shown in Granzow et al, U.S. Patent 4,265,280.
In the illustrated embodiment, the wall means 138 is fabricated from a radiant energy absorbing material. It is thus operative for melting in response to exposure to a source of radiant energy. Furthermore, the material from which the wall means 138 is constructed is purposefully preselected so that it melts only at temperatures which result in the rapid destruction of any bacterial contaminant on the surface of the material (i.e., over 200°C). To permit the transmission of radiant energy through the housing 140 to the meltable wall means 138, the housing 140 is made of a material which does not absorb the particular type of radiant energy selected.
In the preferred embodiment, the wall means 138 is made of a material fabricated from poly(4-methyl-l-pentene), which is sold under the trademark TPX by Mitsui Chemical Company. This material has a crystalline melting point of approximately 235βC, and is further discussed in
Boggs et al U.S. Patent 4,325,417. The material of the wall means 138 is colored black so as to absorb infrared radiation. The housing 140 is made of a clear TPX material which is generally transparent to the passage of infrared radiation.
As can be best seen in Fig. 5, the connecting means 134 takes the form of mating bayonet-type coupling mechanisms, which serve to interlock the connector means 130 and 132 together with their radiant energy absorbing wall means 138 in facing contact (see Fig. 7). * When exposed to a light-induced melting apparatus 150, which, in the illustrated embodiment, cons'ists of an incandescent quartz lamp 151 focused on the opaque, light-absorbing wall means 138, the radiant energy absorbing wall means 138 melt and fuse together, as can be seen xn Fig. 8. In the process of melting, the wall means 138 form a hermetically sealed opening 152 which establishes through the connector means 130 and 132 a fluid path which is at once sterile and closed to communication with the atmosphere.
As the following Example demonstrates, the utilization of the illustrated connector means 130 and 132 assures a probability of non-sterility which exceeds 10- .
EXAMPLE A methanol suspension of 1.5 x 10 Bacillus subtilis var niger (globiguii) spores per milliliter was prepared. This organism was chosen because of its high resistance to dry heat (see Angelotti, et al, "Influence of Spore Masture Content
on the Dry Heat Resistance of Bacillus subtilis var niger", Appl. Microbiol., v 16 (5); 735-745, 1968). Eighty (80) uncoupled sterilized connector members (i.e., forty (40) pairs) identical to the connector means 130 and 132 shown in Figs. 5 through 8, were inoculated with 0.01 milliliter of the B^ subtilis var niger (globiguii) suspension. This constituted exposure of the associated wall means 138 of each connector member 130 and 132 to approximately one million (i.e., 10 ) spores of the organisms. Forty (40) of the. inoculated uncoupled connectors were each attached to empty, sterile containers. The other forty (40) were each attached to containers containing a sterile microbiological growth medium (soybean casien digest (SCD) broth). These inoculated pairs of connector members will hereafter'be referred to as the Test Connectors.
Sixteen (16) additional uncoupled and sterilized connector members (i.e., eight (8) pairs) were inoculated only with methanol. Eight (8) of the connectors were each attached to empty, sterile containers, and eight (8) were each attached to sterile containers containing the SCD broth. These will hereafter be referred to as Negative Control Connectors.
The Test Connectors were coupled together, forming forty (40) connections between the empty containers and the SCD broth containers. The noninoculated Negative Control Connectors were also coupled together, forming eight (8) connections between the empty containers and the SCD broth containers. Each connection was placed within the
light-induced melting apparatus 90 as heretofore described to fuse the membranes together and open a fluid path. The medium was then passed through the connections.
5 Eight (8) additional and already fused connector members were inoculated as Positive
Controls. Two of these connections were inoculated with a theoretical challenge of 10 B_ subtilis var niger (globigii) spores per connection; two were
4 10 inoculated with a theoretical challenge of 10 spores per connection; two were inoculated with a
2 theoretxcal challenge of 10 spores per connection; i and two were x.noculated wxth a theoretxcal challenge
* I of 101 spores per connectxon. Medium was the
I 15 flushed through the fluid path of these Positive
Control Connectors. t
1 All units were incubated at approximately
I 32° to 37°C for up to seven days. After incubation, all turbid broths were subcultured to SCD agar and < 20 incubated for 18 to 24 hours at approximately 32° to
I 37°C. The subcultures were examined for the presence j of orange colonies, which is characteristic of the indicator organism.
Upon examination of the forty (40) Test 25 Connections, no turbid broths were observed. All eight (8) Negative Controls also remained negative during incubation.
All eight (8) Positive Controls demonstrated growth of the indicator organism at all inoculum 30 levels.
The system 11 shown in Fig. 4 comprises a series of initially separate subasse blies which can be easily manufactured, packaged, sterilized, shipped, and stored. The system 11 so provided gives the operator the flexibility to conveniently tailor the configuration of the system 11 to meet the collection objectives of the particular procedure. These significant benefits are achieved without a substantial probability of non-sterility to the system.
The systems 10 and 11, each of which embodies the features of the invention, permit the maximum yields and the maximum storage times permissible for the collected components. Various of the features of the invention are set forth in the following claims.
CMPl