IE903834A1 - Apparatus and method for collecting and freezing blood¹plasma - Google Patents

Description

APPARATUS AND METHOD FOR COLLECTING AND FREEZING BLOOD PLASMA The present invention relates to an apparatus and method for storing and freezing a liquid. More particularly, the present invention relates to an apparatus and method for collecting, storing, freezing and removing a frozen liquid from a plastic container, wherein the liquid is generally blood plasma .

This invention is concerned with a modification of the disclosure of Irish patent application no. 3647/89.

This earlier application claims a method for collecting and freezing plasma comprising: providing a container comprising: a pair of substantially flat flexible opposing sidewalls, which sidewalls are substantially adjacent when the container is in an unfilled condition so as to provide an empty lay-flat configuration; said sidewalls being peripherally sealed together to define an interior compartment; means for accessing said interior compartment; collecting a quantity of plasma in said container; shaping the filled container into a configuration whereby said sidewalls converge toward said one end of said container; and; freezing the filled container while maintaining the container in said configuration.

The earlier application also claims a container having a frozen plug therein, wherein made according to the above method.

The disclosure of the earlier application includes a multiple container collection apparatus (10) comprising a donor bag (12), a platelet bag (14) and a plasma bag (16). The plasma bag has side seams which converge towards one end of the container, in the lay-flat configuration of the container. The platelet bag (14) has a similar construction, but the donor bag (12) has substantially parallel side seams.

The present invention provides a method for collecting and freezing plasma, comprising a pair of substantially flat flexible opposing sidewalls, which sidewalls are substantially adjacent when the container is in an unfilled condition so as to provide an empty lay-flat configuration; said sidewalls being peripherally sealed together to define an interior compartment; means for accessing said interior compartment wherein the peripheral seal defines a pair of substantially parallel side seals between said one end and the opposite end of the container, in the empty lay-flat configuration of the container; collecting a quantity of plasma in said container; shaping the filled container into a configuration whereby said sidewalls converge toward said one end of said container; and freezing the filled container while maintaining the container in said configuration .

Reference is now made to the accompanying drawings, wherein: Figure 1 is a plan view of an interconnected, sealed, multiple bag blood collection system; Figure 2 is a cross-sectional view of a blood plasma bag, taken along line 2-2 of Fig. 1; Figure 3 is a perspective view of a plasma-filled bag being inserted into a form for freezing in accordance with the method of the present invention; Figure 3A is a top view of the form of Fig. 3 in the closed Figure 3A is a position; Figure 3B is a Figure 3C is , cover shown in the ι Figure 4 is a Fig. 3 in assembled side; Figure 5 is a Figure 3B is a front elevation view of the form of Fig.3; Figure 3C is a side view of the form of Fig. 3, with the Figure 4 is a cross-sectional view of the bag and form of Figure 5 is a perspective view of a wedge-shaped bag of frozen plasma, produced according to the present invention; Figure 6 is a side view of the bag being cut open; and Figure 7 is a side view of the bag after it has been cut open, showing the frozen plasma slug being expelled.

Referring to Fig.l, there is shown an interconnected, sealed multiple blood bag collection system 10 including a donor bag 12, a platelet bag 14 and a plasma bag 16. For receiving whole blood into the donor bag, the system 10 includes blood collection tubing 18 which communicates with the interior of the donor bag 12 through port 20. The tubing 18 blood collection needle 22, shown with its includes a blood sampling port 24, all construction. For transferring blood components another, the system 10 may also include tubing 26, which extends from a second port 28 of the donor bag to a Y-fitting 30. Additional tubing segments 32 and 34 extend from the Y-fitting 34 to the plasma and platelet bags 14 and 16, respectively.

In brief, the system 10 may be used with blood collection and fractionation as follows. After whole blood is collected in the donor bag 12, the donor bag 12 and its contents are centrifuged at 1100 x g to separate the whole blood into two layers: a lower layer of packed red cells and an upper layer of platelet-containing plasma. The donor bag is then manually manipulated as by squeezing to express the platelet rich plasma into platelet bag 14. For isolating the platelet and plasma bags until access is required, a valve means such as a frangible cannula 36 may be provided in the outlet from the donor bag 12. More particularly, the frangible cannula 36 may be of the design depicted in U.S. Patent Nos. 4,181,140 or 4,299,247, and openable by external manipulation of the tubing 26 to fracture the cannula and allow flow through tube 26.

Following transfer of the platelet-rich plasma, the tube 26 may be sealed and severed. In a two-bag system, platelet-rich plasma in the platelet bag 14 could be frozen, as described below. In a three bag system, as shown at 10, additional steps may be carried out. For example, it may be desirable to add a preservative to the red blood cells remaining in the donor bag 12. In a three bag blood collection system, such as is'shown at 10, the plasma bag 16 may contain a quantity of red blood cell preservation fluid, such as ADSOL Preservation solution, manufactured by Fenwal Laboratories Division of Baxter Healthcare, Inc. of Deerfield, Illinois, U.S.A., 60015, or its equivalent.

The red blood cell preservation solution in the plasma bag 16 can be manually expressed into the tube 34 through a valve means 3 8 and into the donor bag 12. The valve means 38 may be similar in configuration to the frangible cannula 36. The tube 2 6 is then sealed and cut, and donor bag 12 is stored and used as needed.

Once the platelet rich plasma has been transferred to the platelet bag 14 and the donor bag is severed, the platelet bag 14 is then centrifuged to make a lower layer of platelet concentrate and an upper layer of platelet-poor plasma. The platelet-poor plasma is transferred via the tube 32, the connector 30 and the tube 34 into the now empty plasma bag 16. Tubes 32 and 34 are then sealed, and the two bags 14 and 16 are severed for their various uses.

As best seen in Figs. 1 and 2, the plasma bag 16 comprises a pair of substantially flat, flexible, opposing sidewalls 40, 42, preferably made of a vinyl material such as polyvinyl chloride, although other materials may also be used without departing from the present invention. The sidewalls 40 and 42 are substantially adjacent when the bag 16 is in an unfilled condition, so that the bag 16 is in a lay-flat configuration when empty. This lay-flat configuration provides an easily packaged blood collection system 10, which takes up little storage space before use.

The sidewalls 40 and 42 of the plasma bag 16 are sealed together around the entire periphery at side seams 44 and 46, bottom seam 48, and top seam 50, to define an interior compartment. The seams can be of any conventional sealing method appropriate to the material chosen. For bags made of vinyl material such as polyvinyl chloride, the sidewalls may simply be heat sealed together along the edge seams.

The side seams 44 and 46 of the plasma bag 16 are substantially parallel between the top seam 50 and the bottom seam 48.

The plasma bag 16 has in this embodiment a capacity of approximately 300 ml. In the preferred embodiment, however, the plasma bag 16 will not be filled in its entirety. Instead, it will be filled to approximately 250 ml. with approximately 30-35 cc of air. The air space allows for expansion while the contents are freezing. Furthermore, and importantly, after the contents are frozen, the air space permits a cutting means to cut the top off of the transfer bag without contacting the contents, as will be discussed below.

In this embodiment, the plasma bag 16 is provided with two plastic port tubes 52, 54 for accessing the interior, as is well known in the art. The port tubes 52 and 54 are sealed adhesively or thermally between the sidewalls 40 and 42. As best seen in Fig. 2, the port tubes 52 and 54 contain an intermediate, frangible membrane 56 which seals the port tubes 5 2 and 54 until such time as the seal is manually broken. The port tubes 52 and 54 are covered by port protectors, such as peel-apart tabs 58, which normally seal the port tubes 52 and 54 and keep them sterile, until access to the interior of bag 16 is required for infusion, for example.

The platelet-poor plasma in plasma bag 16 may be used for a subsequent infusion or processed into other blood fractions. In any event, it is typically frozen to increase its useful life. In accordance with the present invention, the plasma bag 16 is preferably placed into a form as shown generally at 60, for freezing. The form 60 shapes the container to provide a configuration which is more conducive for extraction of the frozen plasma, and which is less likely to cause plasma-trapping tucks and folds in the frozen transfer bag.

Turning now to Figs. 3 to 3C, the form 6 0 is shown. As best seen in Fig. 3, the form 60 has a cover portion 62 hinged at 64 to a back portion 66. The cover 62 is pivotal in relation to the back 6 6 between a first or open position, as seen in Figs. 3 and 3c, and a second or closed position, as seen in Figs. 3a and 3b. In the open position the form 60 can receive one or more plasma bags 16 between the cover 62 and the back 66. In the closed position, the form 60 encloses the plasma bag 16, and the form 60 engages the sidewalls and presses them into a Vshape.

An L-shaped latch 68 is provided in order to hold the cover 62 and the back 66 together during the molding and freezing process. The latch 68 is pivotally mounted at hinge' 70 and movable to a latched position as seen in Figs. 3a, 3b and 4, where it engages over the top edge of the back portion 66.

When contained within the form 60, plasma bag 16 and thus the liquid inside are formed into a wedge-shape. The sides 72 and 74 of the form are triangular converging from a top side 76 of the form 60 preferably continuously down towards the hinge 64 as shown in Fig. 3c.

After a filled plasma bag 16 is placed within the form 60, the form is suspended by hangers 78 and 80 within a blast In the preferred embodiment, the freezer unit (not shown), hangers are oppositely extending configurations of hangers will work, this purpose are well-known in the art.

Figure 4 shows a cross-sectional view of the form 6 0 and plasma bag 16 cut away to show the liquid inside, during the freezing process. An air space 82 is left at the top of the plasma bag 16 when it is filled with liquid, to facilitate opening of the plasma bag 16 at the manufacturing site, discussed below in connection with Figure 6, and to permit expansion of the liquid during the freezing process.

To promote freezing, the form 60 is constructed of a thermally conductive material, such as stainless steel, aluminium or the like. Furthermore, the cover 62 and the back 66 of the form 60 are ventilated with perforation holes 84 to promote cold air circulation and thus freezing. The perforations 84 are an evenly spaced matrix, with the number of perforations depending on the size, application, desired freezing time and the like. rods, although other Blast freezer units for After freezing, the frozen plasma bag 16 will have substantially the conformation seen in Fig. 5. If the contents of the plasma bag 16 are to be removed from the transfer bag in the frozen state, for example, for further processing, the plasma bag 16 must be opened. To accomplish this, the top of the plasma bag 16 is completely removed, as by a knife 86 illustrated in Fig. 6. The removal process may be manual or automatic. In either case, the presence of the air space 82 in the top of the plasma bag 16 allows the top to be removed without contacting the frozen plasma.

The surface of the plasma bag 16 is then, warmed by quickly heating the surface with warm water, steam, or electro-magnetic radiation, as is known in the art. This warming releases the frozen plasma slug from container wall, and the frozen plasma slug 88 can be simply and quickly removed in a single piece by inverting the bag, as shown in Figure 7. The removal process may be manual or automatic. For example, the frozen slug 88 could also be forced out by two counter rotating rollers or other devices, as shown in U.S. Patent No. 4,253,458, Figure 4 and corresponding text.

Claims (14)

1. -, CLAIMS »< 1. A method for collecting and freezing plasma, comprising a pair of substantially flat flexible opposing sidewalls, which sidewalls are substantially adjacent when the container is in an unfilled condition so as to provide an empty lay-flat configuration; said sidewalls being peripherally sealed together to define an interior compartment; means for accessing said interior compartment wherein the peripheral seal defines a pair / of substantially parallel side seals between said one end and < the opposite end of the container, in the empty lay-flat configuration of the container; collecting a quantity of plasma > in said container; shaping the filled container into a ' configuration whereby said sidewalls converge toward said one < end of said container; and freezing the filled container while s maintaining the container in said configuration.

2. A method in accordance with Claim 1 wherein the step of shaping includes placing said container between a pair of converging walls, defining a V-shape with the sidewalls engaging the converging walls so that the sidewalls are pressed into a ν'shape .

3. A method in accordance with Claim 1 or 2, further .: comprising the step of placing the shaped container in a t freezer.

4. A method in accordance with Claim 1, 2 or 3 further comprising thawing the outer layer of said frozen plasma.

5. A method in accordance with any preceding claim wherein the method further comprises removing the other end of said container.

6. A method in accordance with Claim 5 wherein said removing step comprises cutting said other end of said container without contacting the frozen plasma.

7. A method in accordance with Claim 5 or 6, wherein the method further comprises expelling said frozen plasma out said cut end .

8. A method according to Claim 1 for collecting and freezing plasma, substantially as hereinbefore described.

9. A container having a frozen plasma slug therein, when made according to the method of Claim 1, 2, or 3.

10. A container according to Claim 9, whose sidewalls are made from polyvinyl chloride.

11. A container in accordance with Claim 9 or 10 wherein said means for accessing said interior compartment further comprises at least one tubular inlet at the other end.

12. A container in accordance with Claim 11 further comprising flexible tubing communicating with said tubular inlet.

13. A container in accordance with one one of Claims 9 to 12, wherein said plasma is substantially free of platelets.

14. A container in accordance with any one of Claims 9 to 13, wherein said quantity of plasma is sufficiently smaller than the volume of said interior compartment to allow an unfilled space at said other end whereby said other end may be removed without contacting said plasma.