US 3074402 A
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dfiidAhZ Patented Jan. 22, 1%63 3,tl74,4t)2 Ell/9G2) HANDLENG EQUILPMENT tjyrus R. Brennan, Evanston, EL, assignor to Baxter Laboratories, lno, Morton Grove, Ill, a corporation of Delaware Filed flan. 4, 1969, Ser. No. 169 9 Claims. (Cl. 128-214) This invention relates to blood handling equipment and, more particularly, to equipment utilized during the separation of the plasma component of blood.
Plasma constitutes about 4555% of whole blood, the remainder being the red cells. The red cells carry the identifying characteristics of a particular blood, so that whole blood can only be administered to a patient selectively. On the other hand, plasma is universally acceptable and is widely used to make up blood loss in injury, surgery, etc. Whole blood can only be stored, even under refrigeration, for a period less than about one month because of the deterioration of the red cells hemolysis. On the other hand, plasma does not so deteriorate, so the available life of plasma is considerably longer. The beneficial use of plasma also offers an excellent salvage for outdated blood.
In the past, blood has been collected for storage in rigid glass bottles. After a time, the heavier red cells separated from the plasma and, if desired, it was possible to cleanly draw off the plasma. In most cases, this was done by aspirating equipment in which an evacuated container was connected to the blood storage bottle through the use of a tube and needle set. The blood bottle was vented to the atmosphere, and the blood bottle needle inserted below the plasma level. The atmospheric pressure operated to force the plasma through the tube and needle set into the low pressure vessel. It was possible to obtain a fairly clean-cut separation between the plasma and red cells because of the stability of the interface made possible through the rigid glass blood storage bottle. However, the transfer was delicate, since inadvertent withdrawal of the blood bottle needle from the plasma would permit air to short-circuit into the plasma collection vessel and break the vacuum.
With the advent of flexible blood collection containers, more commonly referred to as blood bags, there has arisen a problem in the separation of the plasma from the red cells. There is no longer present the stabilized interface between the tWo components, since the bag walls automatically collapse as some liquid is Withdrawn. This may result in an upset of the interface and a wasteful mixing of portions of the red cells and plasma at the interface-resulting in the loss of valuable plasma. Here, it is to be appreciated that the plasma separated from the red cells must be substantially free therefrom to be useful as a blood supplement. Even though the red cells administered as part of plasma may be of the proper character, if unduly hernolyzed, they can prove deleterious to the recipient.
It is a principal object of this invention to provide a novel apparatus for the separation of plasma from whole blood when the blood is stored in flexible containers. Another object is to provide a plasma-handling device that is eifective to stabilize the interface developed between layers of plasma and red cells so as to effect a clean-cut separation of plasma from the red cells and in maximum quantity. Still another object is to provide a unique device for pressurizing a flexible blood container. Other objects and advantages of this invention can be seen as this specification proceeds.
The invention, in an illustrative embodiment, will be explained in conjunction with the accompanying drawing, in which- FIG. 1 is a perspective view of equipment utilized in the separation of plasma from whole blood contained within a flexible storage container and which embodies teachings of this invention;
FIG. 2 is a fragmentary top plan view of a portion of the apparatus seen in MG. 1, with different operative positions of the apparatus illustrated in dashed line;
FIG. 3 is an elevational view of the apparatus seen in PEG. 2;
FIG. 4 is an elevational view of the pressure-applying member of the apparatus seen in FIG. 1 and in an intermediate stage of fabrication; and
P16. 5 is an enlarged fragmentary cross-sectional view, taken along the line 5--5 of FIG. 2.
In the illustration given, the numeral it} designates generally a blood collection and storage container of the flexible-walled type. The container to is illustrated and described in greater detail in the copending application of Harrison and Broman, Serial No. 772,951, filed November 10, 1958, and reference may be had to that application for additional details of construction not found herein.
The container It} is constructed of a thermoplastic material such as polyvinyl chloride, with the various wall portions united by heat-sealing. This material is fairly transparent and is hemorepellent. The shape of the container 10, when liquid-filled, is much like that of a rectangular solid, in that a discrete end wall exists iirom which side walls upstand. The upper end wall ltla is equipped with a series of flow fittings. In the ordinary operation, blood is introduced into the container 1% through the fitting 11 which is equipped with a resilient closure 12 adapted to reseal itself after being pierced by a delivery cannula (not sh wn). The delivery cannula is provided as part of a donor or collection set and communicates at its other end via a length of tubing with the arm of the donor. In the illustration given, the fitting M has already been used for the purpose of filling the container It? with blood, and the donor set discarded.
The end wall Illa is also equipped with a delivery fitting 13 which, when whole blood is to be administered, provies the place for connection of an administration set (not shown). The conventional administration set also includes a flexible tube equipped with needles at the ends thereof for the purpose of establishing communication between the interior of container to and the vascular system of the intended recipient.
Where, however, it is desired to separate plasma from the whole blood, either for the purpose of salvaging outdated whole blood or for the purpose of securing plasma from still useful blood, a third fitting 14 is employed. This fitting, like fitting 11, is equipped with a self-sealing closure through which the needle 15 of a plasma aspiration set generally designated 15 is inserted.
The set 16, at the other end of the flexible tubing 17, includes a flask needle '18 which is inserted through the stopper 19 of a plasma collection vessel 29. The stopper 19 of the vessel 29 is vented by means of an airway cannula 21 so that atmospheric pressure exists Within the vessel 2-9. The stopper closure 19, where pierced by the needle 18 and the cannula 2a is of a character adapted to reseal itself, so that the plasma in container 2% can be stored without possibility of contamination by contact with air-borne microorganisms, or the like.
Still referring to FIG. 1, it is to be seen that the generally box-shaped container 18 is encircled by a perimetric body generally designated by the numeral .22 and which provides the means for pressurizing the container 10 so as to force the plasma therefrom and into the vessel 29.
Now referring to FIG. 2, it is seen that the body 22 includes an inner wall 23 and an outer wall 24 on each r a o of the four sides of the container in, these walls shown also in dotted line to indicate their positions when the body 22 is distended. When a pressurized fluid such a air is introduced between these walls, the walls are urged apart and into the configurations designated 23a and 24a in FIG. 2. The elevational aspect of the inner wall 23 can be appreciated from a consideration of BIG. 3, wherein the dashed lines designated 23a, 23b and 230 represent successive inflated positions of wall 23.
For the purpose of inflating the member 22, a check valve-equipped squeeze bulb 25 may be provided'which is coupled by means of a tube 26 to a flow port 27. The flow port 27 is installed in an edge portion of the member 22 and communicates between the inner and outer walls 23 and 24, respectively. In the preferred construction, the member 22 utilizes a heat sealable plastic material such as polyvinyl chloride, and the fitting 27 is constructed of like material so that a rigid, air-tight assembly is readily achieved. a
In the fabrication of the mem er 22, two or more sheets of thermoplastic material, each having a generally rectangular configuration, are assembled in face-toface, superposed relation to provide a blank of the genend outline seen in FIG. 4 and which is designated 22a. The wall-forming sheets are then perimetrica lly united to form a closed envelope, one of the edges being interrupted in its union to provide a place for the insertion of the fitting 27. The shorter edge portions of the edge 22a, as illustrated, are brought together and united to.
form a seam 22bsee FIG. 2. Intermediate the edges 28 and 29 so brought together and united, the walls 23 and 24 making up the blank or envelope 22a are united together along a series of spaced lines 29, 30 and 31 (see FIG. 4). The structure thus developed provides a boxlike, open-ended configuration which serves as an inflatable cuff for the container 10. The unions, along the lines 29, 3t and 31 are interrupted so as to provide communication between the tour chambers 32, 33, 34 and 35 and thereby equalize the pressure in each of these chambers, each chamber abutting against a side wall of the generally rectangular container 19. I have found that additional advantages accrue from employing three or more sheets a in making up the walls 23 and 24, the outer center Wall 24- comprising at least two sheets. This results in a stifier outer wall 24 so that distention produced by internally pressurizing the body preferentially occurs in the wall 23 and thus inward-1y of the body 22 rather than outwardly.
The walls 23 and 24 have a height approximately that of the container 10, and when expanded to the condition shown in dotted line in FIG. 3, serve to divide the internal volume of the con-t ainer into two approximately equal parts. Thus, the inwardly-distended walls of the container restrict the interface and permit the achievement or a clean cut separation of the plasma and red cells.
Thus, the inflatable cufl provides an effective device for the separation of the red cells and plasma, ordinary blood comprising about 55% red cells and 45% plasma. The inward distention of the walls of the cult at about the center of the height of the container means that there is an eiiective separation between the cells and plasma.
in the employment of containers such as that designated by the numeral 10in the drawing, there is also a worthwhile application of the cuff for the purpose of accelerating the outflow of whole blood during the course of administration thereof to a human patient. 'In this environment, the cult is especially desirable since it permits the application of a gentle but steady pressure on the whole blood, which has been found effective in elimi- V While, in the foregoing specification, l have set forth a detailed description of an embodiment of the invention for the purpose of explanation thereof, many variations in the details herein given may be seen by those skilled in the art without departing from the spirit and scope of the invention.
1 in combination, a flexible blood storage container which attains the shape of a rectangular solid when' liquid-filled, said solid having a discrete end'wall'as well as side walls upstanding therefrom, discharge conduit means connected to said container, an inflatable cuff for said container comprising inner and outer walls united together along opposite parallel edges, and a flow fitting in said cult for introducing pressurized fluid between said walls, said cuff being disposed about said side walls and when inflatedto compress a central portion of said container to divide the interior container volume into volumes containing plasma and red cells, respectively.
2. The apparatus of claim 1 in which a plasma colleclection vessel is connected to said conduit means, said vessel being equipped with vent means establishing atmospheric pressure therein.
3. In combination, a flexible blood collection and storage container having discrete end walls as well as side walls extending therebetween, said container adapted 4. The structure of claim 3 in which said body comprises inner and outer walls arranged in face-to-fiace relation, the pressurized fluid being eflective'to urge said walls apart and thereby partially collapse said container.
5. The structure of claim 4 in which said inner' and outer walls are united together along spaced lines to provide said chambers, some of the unions between walls being interrupted to provide said equalizing means.
6. The structure of claim 3 in which said body comprises a plurality of generally rectangular sheet-s arranged in face-todace, superposed relation and perimetrically united together, said sheets being additionally united together along spaced interrupted lines parallel to a pair of opposite edges of said superposed sheets, said pair of opposite edges being united together to provide an open ended box-like structure, and 1a flow port communicating with the space between said sheets and being positioned in one of the edges of said superposed'sheets other than saidpair of opposite edges.
7. in combination with a flexible blood storage container adapted to be compressed intermediate its. length to divide the interior space into approximately equal volumes, said container being equipped with an end wall, a plurality oi side walls upstanding therefrom with the side wall-s extending generally. lengthwise of the container, a liquid exit fitting in Said end wall, means connecting said fitting to a plasma collection vessel, a hollow open-ended member disposed perimetric-ally about said container and in'contact with each of said sidewalls, said member having flexible inner and outer walls united together along spaced lines to provide an inflation chamber effective to provide intermediate compression of said container, and means for internally pressurizing said chamber;
8. The improvement in the separation of the plasma phase from the blood cells phase of whole blood contained in a rectangular when liquid-filled flexible container which comprises placing said container within a perimetric pressure member, said member comprising a perimertic body constructed of a plurality of sheets of heat-sealable thermoplastic material, each of said sheets bein united together along zhe edges thereof with a pair of opposite edges united together to provide the perimetric shape, said sheets being additionally united together along interrupted lines to provide a generally box shaped member with a plurality of communicating chambers, and means for internally pressurizing said body to inflate the same, internally pressurizing said body to infiate the same and distend the walls of the rectangular container inwardly thus resulting in a reduction in the cross-sectional area of the container at the interface point of the plasma and blood cell phases so as to facilitate the removal of the maximum amount of plasma without removal of blood cells.
9. A pressure device for facilitating the separation of plasma from blood in a flexible blood container, comprising a perimetric body constructed of an outer and an inner member of heat-sealable thermoplastic material, each of said members being rectangular and arranged in :face-to-face superposed relation, said members being united together along the edges thereof with a pair of opposite edges united together to provide a perimetric shape, said members being additionally united together along interrupted lines to provide a generally box-shaped device with a plurality of communicating chambers, said outer member which forms the outer Wall of said device being of a stiffer nature than said inner member, whereby the distention produced by internally pressun'zing said device preferentially occurs inwardly rather than outwardly.
References Cited in the file of this patent UNITED STATES PATENTS 1,457,496 Butler June 5, 1923 2,597,715 Erik-son May 20, 1952 2,766,907 Wallace Oct. 16, 1956 2,847,007 Fox Aug. 12, 1958 2,943,859 Koski July 5, 1960 OTHER REFERENCES Walter et al.: A Closed Gravity Technique for the Preservation of Whole Blood in ACD Solution Utilizing Plastic Equipmen from Surgery, Gynecology and Obstetrics, Volume 94, #6, June 1952, pp. 687-692. (Copy in Division 55.)